targets/gba: implement interrupt handler

Make it clearer where the stack is located.

.circleci/config.yml

@@ -18,7 +18,6 @@ commands:
             wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key|sudo apt-key add -
             sudo apt-get update
             sudo apt-get install \
-                python3 \
                 llvm<<parameters.llvm>>-dev \
                 clang<<parameters.llvm>> \
                 libclang<<parameters.llvm>>-dev \
@@ -67,7 +66,7 @@ commands:
       - run: go install .
       - run: go test -v ./cgo ./compileopts ./interp ./transform .
       - run: make gen-device -j4
-      - run: make smoketest RISCV=0
+      - run: make smoketest
       - save_cache:
           key: go-cache-v2-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_BUILD_NUM }}
           paths:
@@ -83,7 +82,6 @@ commands:
           name: "Install apt dependencies"
           command: |
             sudo apt-get install \
-                python3 \
                 gcc-arm-linux-gnueabihf \
                 binutils-arm-none-eabi \
                 libc6-dev-armel-cross \
@@ -122,12 +120,6 @@ commands:
           key: llvm-build-9-linux-v0-assert
           paths:
             llvm-build
-      - run:
-          name: "Create LLVM symlinks"
-          command: |
-            ln -s $PWD/llvm-build/bin/clang-9 /go/bin/clang-9
-            ln -s $PWD/llvm-build/bin/ld.lld  /go/bin/ld.lld-9
-            ln -s $PWD/llvm-build/bin/wasm-ld /go/bin/wasm-ld-9
       - run: make ASSERT=1
       - run:
           name: "Test TinyGo"
@@ -139,7 +131,7 @@ commands:
             - ~/.cache/tinygo
             - /go/pkg/mod
       - run: make gen-device -j4
-      - run: make smoketest TINYGO=build/tinygo RISCV=0
+      - run: make smoketest TINYGO=build/tinygo
   build-linux:
     steps:
       - checkout
@@ -148,7 +140,6 @@ commands:
           name: "Install apt dependencies"
           command: |
             sudo apt-get install \
-                python3 \
                 gcc-arm-linux-gnueabihf \
                 binutils-arm-none-eabi \
                 libc6-dev-armel-cross \
@@ -187,12 +178,6 @@ commands:
           key: llvm-build-9-linux-v0
           paths:
             llvm-build
-      - run:
-          name: "Create LLVM symlinks"
-          command: |
-            ln -s $PWD/llvm-build/bin/clang-9 /go/bin/clang-9
-            ln -s $PWD/llvm-build/bin/ld.lld  /go/bin/ld.lld-9
-            ln -s $PWD/llvm-build/bin/wasm-ld /go/bin/wasm-ld-9
       - run:
           name: "Test TinyGo"
           command: make test
@@ -216,11 +201,6 @@ commands:
             tar -C ~/lib -xf /tmp/tinygo.linux-amd64.tar.gz
             ln -s ~/lib/tinygo/bin/tinygo /go/bin/tinygo
             tinygo version
-      - run:
-          name: "Download SiFive GNU toolchain"
-          command: |
-            curl -O https://static.dev.sifive.com/dev-tools/riscv64-unknown-elf-gcc-8.2.0-2019.05.3-x86_64-linux-ubuntu14.tar.gz
-            sudo tar -C /usr/local --strip-components=1 -xf riscv64-unknown-elf-gcc-8.2.0-2019.05.3-x86_64-linux-ubuntu14.tar.gz
       - run: make smoketest
   build-macos:
     steps:
@@ -264,10 +244,6 @@ commands:
           key: llvm-build-9-macos-v0
           paths:
             llvm-build
-      - run:
-          name: "Create LLVM symlinks"
-          command: |
-            ln -s $PWD/llvm-build/bin/clang-9 /usr/local/bin/clang-9
       - run:
           name: "Test TinyGo"
           command: make test

CHANGELOG.md

@@ -1,3 +1,29 @@
+0.11.0
+---
+* **command line**
+  - add support for QEMU in `gdb` subcommand
+  - use builtin Clang when building statically, dropping the clang-9 dependency
+  - search for default serial port on both macOS and Linux
+  - windows: support `tinygo flash` directly by using win32 wmi
+* **compiler**
+  - add location information to the IR checker
+  - make reflection sidetables constant globals
+  - improve error locations in goroutine lowering
+  - interp: improve support for maps with string keys
+  - interp: add runtime fallback for mapassign operations
+* **standard library**
+  - `machine`: add support for `SPI.Tx()` on play.tinygo.org
+  - `machine`: rename `CPU_FREQUENCY` to `CPUFrequency()`
+* **targets**
+  - `adafruit-pybadge`: add Adafruit Pybadge
+  - `arduino-nano33`: allow simulation on play.tinygo.org
+  - `arduino-nano33`: fix default SPI pin numbers to be D13/D11/D12
+  - `circuitplay-express`: allow simulation on play.tinygo.org
+  - `hifive1-qemu`: add target for testing RISC-V bare metal in QEMU
+  - `riscv`: fix heap corruption due to changes in LLVM 9
+  - `riscv`: add support for compiler-rt
+  - `qemu`: rename to `cortex-m-qemu`
+
 0.10.0
 ---
 * **command line**

CODE-OF-CONDUCT.md

@@ -0,0 +1,76 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to make participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies within all project spaces, and it also applies when
+an individual is representing the project or its community in public spaces.
+Examples of representing a project or community include using an official
+project e-mail address, posting via an official social media account, or acting
+as an appointed representative at an online or offline event. Representation of
+a project may be further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at [conduct@tinygo.org](mailto:conduct@tinygo.org). All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see
+https://www.contributor-covenant.org/faq

Dockerfile

@@ -41,9 +41,8 @@ COPY --from=tinygo-base /tinygo/lib /tinygo/lib
 
 RUN cd /tinygo/ && \
     apt-get update && \
-    apt-get install -y apt-utils python3 make binutils-avr gcc-avr avr-libc && \
+    apt-get install -y apt-utils make binutils-avr gcc-avr avr-libc && \
     make gen-device-avr && \
-    apt-get remove -y python3 && \
     apt-get autoremove -y && \
     apt-get clean
 
@@ -59,11 +58,8 @@ COPY --from=tinygo-base /tinygo/lib /tinygo/lib
 
 RUN cd /tinygo/ && \
     apt-get update && \
-    apt-get install -y apt-utils python3 make clang-9 && \
+    apt-get install -y apt-utils make clang-9 && \
-    make gen-device-nrf && make gen-device-stm32 && \
+    make gen-device-nrf && make gen-device-stm32
-    apt-get remove -y python3 && \
-    apt-get autoremove -y && \
-    apt-get clean
 
 # tinygo-all stage installs the needed dependencies to compile TinyGo programs for all platforms.
 FROM tinygo-wasm AS tinygo-all
@@ -74,10 +70,7 @@ COPY --from=tinygo-base /tinygo/lib /tinygo/lib
 
 RUN cd /tinygo/ && \
     apt-get update && \
-    apt-get install -y apt-utils python3 make clang-9 binutils-avr gcc-avr avr-libc && \
+    apt-get install -y apt-utils make clang-9 binutils-avr gcc-avr avr-libc && \
-    make gen-device && \
+    make gen-device
-    apt-get remove -y python3 && \
-    apt-get autoremove -y && \
-    apt-get clean
 
 CMD ["tinygo"]

LICENSE

@@ -3,6 +3,9 @@ Copyright (c) 2018-2019 TinyGo Authors. All rights reserved.
 TinyGo includes portions of the Go standard library.
 Copyright (c) 2009-2019 The Go Authors. All rights reserved.
 
+TinyGo includes portions of LLVM, which is under the Apache License v2.0 with
+LLVM Exceptions. See https://llvm.org/LICENSE.txt for license information.
+
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:

Makefile

@@ -14,9 +14,6 @@ export GOROOT = $(shell $(GO) env GOROOT)
 # md5sum binary
 MD5SUM = md5sum
 
-# Python binary
-PYTHON ?= python
-
 # tinygo binary for tests
 TINYGO ?= tinygo
 
@@ -34,7 +31,7 @@ endif
 
 .PHONY: all tinygo test $(LLVM_BUILDDIR) llvm-source clean fmt gen-device gen-device-nrf gen-device-avr
 
-LLVM_COMPONENTS = all-targets analysis asmparser asmprinter bitreader bitwriter codegen core coroutines debuginfodwarf executionengine instrumentation interpreter ipo irreader linker lto mc mcjit objcarcopts option profiledata scalaropts support target
+LLVM_COMPONENTS = all-targets analysis asmparser asmprinter bitreader bitwriter codegen core coroutines coverage debuginfodwarf executionengine instrumentation interpreter ipo irreader linker lto mc mcjit objcarcopts option profiledata scalaropts support target
 
 ifeq ($(OS),Windows_NT)
     EXE = .exe
@@ -65,6 +62,11 @@ $(LIBCLANG_PATH): $(LIBCLANG_FILES)
 else ifeq ($(shell uname -s),Darwin)
     MD5SUM = md5
     LIBCLANG_PATH = $(abspath $(LLVM_BUILDDIR))/lib/libclang.a
+else ifeq ($(shell uname -s),FreeBSD)
+    MD5SUM = md5
+    LIBCLANG_PATH = $(abspath $(LLVM_BUILDDIR))/lib/libclang.a
+    START_GROUP = -Wl,--start-group
+    END_GROUP = -Wl,--end-group
 else
     LIBCLANG_PATH = $(abspath $(LLVM_BUILDDIR))/lib/libclang.a
     START_GROUP = -Wl,--start-group
@@ -78,7 +80,7 @@ LLD_LIBS = $(START_GROUP) -llldCOFF -llldCommon -llldCore -llldDriver -llldELF -
 
 # For static linking.
 ifneq ("$(wildcard $(LLVM_BUILDDIR)/bin/llvm-config*)","")
-    CGO_CPPFLAGS=$(shell $(LLVM_BUILDDIR)/bin/llvm-config --cppflags) -I$(abspath $(CLANG_SRC))/include -I$(abspath $(LLD_SRC))/include
+    CGO_CPPFLAGS=$(shell $(LLVM_BUILDDIR)/bin/llvm-config --cppflags) -I$(abspath $(LLVM_BUILDDIR))/tools/clang/include -I$(abspath $(CLANG_SRC))/include -I$(abspath $(LLD_SRC))/include
     CGO_CXXFLAGS=-std=c++11
     CGO_LDFLAGS+=$(LIBCLANG_PATH) -std=c++11 -L$(abspath $(LLVM_BUILDDIR)/lib) $(CLANG_LIBS) $(LLD_LIBS) $(shell $(LLVM_BUILDDIR)/bin/llvm-config --ldflags --libs --system-libs $(LLVM_COMPONENTS)) -lstdc++ $(CGO_LDFLAGS_EXTRA)
 endif
@@ -97,24 +99,28 @@ fmt-check:
 gen-device: gen-device-avr gen-device-nrf gen-device-sam gen-device-sifive gen-device-stm32
 
 gen-device-avr:
-	$(PYTHON) ./tools/gen-device-avr.py lib/avr/packs/atmega src/device/avr/
+	$(GO) build -o ./build/gen-device-avr ./tools/gen-device-avr/
-	$(PYTHON) ./tools/gen-device-avr.py lib/avr/packs/tiny src/device/avr/
+	./build/gen-device-avr lib/avr/packs/atmega src/device/avr/
-	GO111MODULE=off $(GO) fmt ./src/device/avr
+	./build/gen-device-avr lib/avr/packs/tiny src/device/avr/
+	@GO111MODULE=off $(GO) fmt ./src/device/avr
 
-gen-device-nrf:
+build/gen-device-svd: ./tools/gen-device-svd/*.go
-	$(PYTHON) ./tools/gen-device-svd.py lib/nrfx/mdk/ src/device/nrf/ --source=https://github.com/NordicSemiconductor/nrfx/tree/master/mdk
+	$(GO) build -o $@ ./tools/gen-device-svd/
+
+gen-device-nrf: build/gen-device-svd
+	./build/gen-device-svd -source=https://github.com/NordicSemiconductor/nrfx/tree/master/mdk lib/nrfx/mdk/ src/device/nrf/
 	GO111MODULE=off $(GO) fmt ./src/device/nrf
 
-gen-device-sam:
+gen-device-sam: build/gen-device-svd
-	$(PYTHON) ./tools/gen-device-svd.py lib/cmsis-svd/data/Atmel/ src/device/sam/ --source=https://github.com/posborne/cmsis-svd/tree/master/data/Atmel
+	./build/gen-device-svd -source=https://github.com/posborne/cmsis-svd/tree/master/data/Atmel lib/cmsis-svd/data/Atmel/ src/device/sam/
 	GO111MODULE=off $(GO) fmt ./src/device/sam
 
-gen-device-sifive:
+gen-device-sifive: build/gen-device-svd
-	$(PYTHON) ./tools/gen-device-svd.py lib/cmsis-svd/data/SiFive-Community/ src/device/sifive/ --source=https://github.com/posborne/cmsis-svd/tree/master/data/SiFive-Community
+	./build/gen-device-svd -source=https://github.com/posborne/cmsis-svd/tree/master/data/SiFive-Community lib/cmsis-svd/data/SiFive-Community/ src/device/sifive/
 	GO111MODULE=off $(GO) fmt ./src/device/sifive
 
-gen-device-stm32:
+gen-device-stm32: build/gen-device-svd
-	$(PYTHON) ./tools/gen-device-svd.py lib/cmsis-svd/data/STMicro/ src/device/stm32/ --source=https://github.com/posborne/cmsis-svd/tree/master/data/STMicro
+	./build/gen-device-svd -source=https://github.com/posborne/cmsis-svd/tree/master/data/STMicro lib/cmsis-svd/data/STMicro/ src/device/stm32/
 	GO111MODULE=off $(GO) fmt ./src/device/stm32
 
 
@@ -187,6 +193,8 @@ smoketest:
 	@$(MD5SUM) test.wasm
 	$(TINYGO) build             -o test.wasm -tags=pca10056             examples/blinky2
 	@$(MD5SUM) test.wasm
+	$(TINYGO) build             -o test.wasm -tags=circuitplay_express  examples/blinky1
+	@$(MD5SUM) test.wasm
 	# test all targets/boards
 	$(TINYGO) build -size short -o test.hex -target=pca10040-s132v6     examples/blinky1
 	@$(MD5SUM) test.hex
@@ -226,6 +234,8 @@ smoketest:
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=feather-m4          examples/blinky1
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=pybadge             examples/blinky1
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=metro-m4-airlift    examples/blinky1
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=nucleo-f103rb       examples/blinky1
@@ -242,10 +252,8 @@ ifneq ($(AVR), 0)
 	$(TINYGO) build -size short -o test.hex -target=digispark           examples/blinky1
 	@$(MD5SUM) test.hex
 endif
-ifneq ($(RISCV), 0)
 	$(TINYGO) build -size short -o test.hex -target=hifive1b            examples/blinky1
 	@$(MD5SUM) test.hex
-endif
 	$(TINYGO) build             -o wasm.wasm -target=wasm               examples/wasm/export
 	$(TINYGO) build             -o wasm.wasm -target=wasm               examples/wasm/main
 

README.md

@@ -51,6 +51,7 @@ The following 22 microcontroller boards are currently supported:
 * [Adafruit ItsyBitsy M0](https://www.adafruit.com/product/3727)
 * [Adafruit ItsyBitsy M4](https://www.adafruit.com/product/3800)
 * [Adafruit Metro M4 Express Airlift](https://www.adafruit.com/product/4000)
+* [Adafruit PyBadge](https://www.adafruit.com/product/4200)
 * [Adafruit Trinket M0](https://www.adafruit.com/product/3500)
 * [Arduino Nano33 IoT](https://store.arduino.cc/nano-33-iot)
 * [Arduino Uno](https://store.arduino.cc/arduino-uno-rev3)
@@ -62,6 +63,7 @@ The following 22 microcontroller boards are currently supported:
 * [Nordic Semiconductor PCA10040](https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF52-DK)
 * [Nordic Semiconductor PCA10056](https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-DK)
 * [Phytec reel board](https://www.phytec.eu/product-eu/internet-of-things/reelboard/)
+* [PineTime DevKit](https://www.pine64.org/pinetime/)
 * [SiFIve HiFive1](https://www.sifive.com/boards/hifive1)
 * [ST Micro "Nucleo F103RB"](https://www.st.com/en/evaluation-tools/nucleo-f103rb.html)
 * [ST Micro STM32F103XX "Bluepill"](http://wiki.stm32duino.com/index.php?title=Blue_Pill)
@@ -125,3 +127,5 @@ The original reasoning was: if [Python](https://micropython.org/) can run on mic
 ## License
 
 This project is licensed under the BSD 3-clause license, just like the [Go project](https://golang.org/LICENSE) itself.
+
+Some code has been copied from the LLVM project and is therefore licensed under [a variant of the Apache 2.0 license](http://releases.llvm.org/9.0.0/LICENSE.TXT). This has been clearly indicated in the header of these files.

azure-pipelines.yml

@@ -6,7 +6,7 @@ trigger:
 
 jobs:
 - job: Build
-  timeoutInMinutes: 180
+  timeoutInMinutes: 240 # 4h
   pool:
     vmImage: 'VS2017-Win2016'
   steps:
@@ -71,4 +71,4 @@ jobs:
         script: |
           export PATH="/c/Go1.13/bin:$PATH:./llvm-build/bin:/c/Program Files/qemu"
           unset GOROOT
-          make smoketest TINYGO=build/tinygo AVR=0 RISCV=0
+          make smoketest TINYGO=build/tinygo AVR=0

builder/build.go

@@ -33,10 +33,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 	// Compile Go code to IR.
 	errs := c.Compile(pkgName)
 	if len(errs) != 0 {
-		if len(errs) == 1 {
+		return newMultiError(errs)
-			return errs[0]
-		}
-		return &MultiError{errs}
 	}
 	if config.Options.PrintIR {
 		fmt.Println("; Generated LLVM IR:")
@@ -72,22 +69,23 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 
 	// Optimization levels here are roughly the same as Clang, but probably not
 	// exactly.
+	errs = nil
 	switch config.Options.Opt {
 	case "none:", "0":
-		err = c.Optimize(0, 0, 0) // -O0
+		errs = c.Optimize(0, 0, 0) // -O0
 	case "1":
-		err = c.Optimize(1, 0, 0) // -O1
+		errs = c.Optimize(1, 0, 0) // -O1
 	case "2":
-		err = c.Optimize(2, 0, 225) // -O2
+		errs = c.Optimize(2, 0, 225) // -O2
 	case "s":
-		err = c.Optimize(2, 1, 225) // -Os
+		errs = c.Optimize(2, 1, 225) // -Os
 	case "z":
-		err = c.Optimize(2, 2, 5) // -Oz, default
+		errs = c.Optimize(2, 2, 5) // -Oz, default
 	default:
-		err = errors.New("unknown optimization level: -opt=" + config.Options.Opt)
+		errs = []error{errors.New("unknown optimization level: -opt=" + config.Options.Opt)}
 	}
-	if err != nil {
+	if len(errs) > 0 {
-		return err
+		return newMultiError(errs)
 	}
 	if err := c.Verify(); err != nil {
 		return errors.New("verification failure after LLVM optimization passes")
@@ -154,11 +152,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 		for i, path := range config.ExtraFiles() {
 			abspath := filepath.Join(root, path)
 			outpath := filepath.Join(dir, "extra-"+strconv.Itoa(i)+"-"+filepath.Base(path)+".o")
-			cmdNames := []string{config.Target.Compiler}
+			err := runCCompiler(config.Target.Compiler, append(config.CFlags(), "-c", "-o", outpath, abspath)...)
-			if names, ok := commands[config.Target.Compiler]; ok {
-				cmdNames = names
-			}
-			err := execCommand(cmdNames, append(config.CFlags(), "-c", "-o", outpath, abspath)...)
 			if err != nil {
 				return &commandError{"failed to build", path, err}
 			}
@@ -170,11 +164,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 			for _, file := range pkg.CFiles {
 				path := filepath.Join(pkg.Package.Dir, file)
 				outpath := filepath.Join(dir, "pkg"+strconv.Itoa(i)+"-"+file+".o")
-				cmdNames := []string{config.Target.Compiler}
+				err := runCCompiler(config.Target.Compiler, append(config.CFlags(), "-c", "-o", outpath, path)...)
-				if names, ok := commands[config.Target.Compiler]; ok {
-					cmdNames = names
-				}
-				err := execCommand(cmdNames, append(config.CFlags(), "-c", "-o", outpath, path)...)
 				if err != nil {
 					return &commandError{"failed to build", path, err}
 				}

builder/builtins.go

@@ -236,7 +236,11 @@ func CompileBuiltins(target string, callback func(path string) error) error {
 		// Note: -fdebug-prefix-map is necessary to make the output archive
 		// reproducible. Otherwise the temporary directory is stored in the
 		// archive itself, which varies each run.
-		err := execCommand(commands["clang"], "-c", "-Oz", "-g", "-Werror", "-Wall", "-std=c11", "-fshort-enums", "-nostdlibinc", "-ffunction-sections", "-fdata-sections", "--target="+target, "-fdebug-prefix-map="+dir+"="+remapDir, "-o", objpath, srcpath)
+		args := []string{"-c", "-Oz", "-g", "-Werror", "-Wall", "-std=c11", "-fshort-enums", "-nostdlibinc", "-ffunction-sections", "-fdata-sections", "-Wno-macro-redefined", "--target=" + target, "-fdebug-prefix-map=" + dir + "=" + remapDir}
+		if strings.HasPrefix(target, "riscv32-") {
+			args = append(args, "-march=rv32imac", "-mabi=ilp32", "-fforce-enable-int128")
+		}
+		err := runCCompiler("clang", append(args, "-o", objpath, srcpath)...)
 		if err != nil {
 			return &commandError{"failed to build", srcpath, err}
 		}

builder/cc1as.cpp

@@ -0,0 +1,504 @@
+// +build byollvm
+
+//===-- cc1as.cpp - Clang Assembler  --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the entry point to the clang -cc1as functionality, which implements
+// the direct interface to the LLVM MC based assembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/Diagnostic.h"
+#include "clang/Basic/DiagnosticOptions.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "clang/Frontend/Utils.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/MC/MCParser/MCTargetAsmParser.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCTargetOptions.h"
+#include "llvm/Option/Arg.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Option/OptTable.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/Timer.h"
+#include "llvm/Support/raw_ostream.h"
+#include <memory>
+#include <system_error>
+using namespace clang;
+using namespace clang::driver;
+using namespace clang::driver::options;
+using namespace llvm;
+using namespace llvm::opt;
+
+#include "cc1as.h"
+
+bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
+                                         ArrayRef<const char *> Argv,
+                                         DiagnosticsEngine &Diags) {
+  bool Success = true;
+
+  // Parse the arguments.
+  std::unique_ptr<OptTable> OptTbl(createDriverOptTable());
+
+  const unsigned IncludedFlagsBitmask = options::CC1AsOption;
+  unsigned MissingArgIndex, MissingArgCount;
+  InputArgList Args = OptTbl->ParseArgs(Argv, MissingArgIndex, MissingArgCount,
+                                        IncludedFlagsBitmask);
+
+  // Check for missing argument error.
+  if (MissingArgCount) {
+    Diags.Report(diag::err_drv_missing_argument)
+        << Args.getArgString(MissingArgIndex) << MissingArgCount;
+    Success = false;
+  }
+
+  // Issue errors on unknown arguments.
+  for (const Arg *A : Args.filtered(OPT_UNKNOWN)) {
+    auto ArgString = A->getAsString(Args);
+    std::string Nearest;
+    if (OptTbl->findNearest(ArgString, Nearest, IncludedFlagsBitmask) > 1)
+      Diags.Report(diag::err_drv_unknown_argument) << ArgString;
+    else
+      Diags.Report(diag::err_drv_unknown_argument_with_suggestion)
+          << ArgString << Nearest;
+    Success = false;
+  }
+
+  // Construct the invocation.
+
+  // Target Options
+  Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
+  Opts.CPU = Args.getLastArgValue(OPT_target_cpu);
+  Opts.Features = Args.getAllArgValues(OPT_target_feature);
+
+  // Use the default target triple if unspecified.
+  if (Opts.Triple.empty())
+    Opts.Triple = llvm::sys::getDefaultTargetTriple();
+
+  // Language Options
+  Opts.IncludePaths = Args.getAllArgValues(OPT_I);
+  Opts.NoInitialTextSection = Args.hasArg(OPT_n);
+  Opts.SaveTemporaryLabels = Args.hasArg(OPT_msave_temp_labels);
+  // Any DebugInfoKind implies GenDwarfForAssembly.
+  Opts.GenDwarfForAssembly = Args.hasArg(OPT_debug_info_kind_EQ);
+
+  if (const Arg *A = Args.getLastArg(OPT_compress_debug_sections,
+                                     OPT_compress_debug_sections_EQ)) {
+    if (A->getOption().getID() == OPT_compress_debug_sections) {
+      // TODO: be more clever about the compression type auto-detection
+      Opts.CompressDebugSections = llvm::DebugCompressionType::GNU;
+    } else {
+      Opts.CompressDebugSections =
+          llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())
+              .Case("none", llvm::DebugCompressionType::None)
+              .Case("zlib", llvm::DebugCompressionType::Z)
+              .Case("zlib-gnu", llvm::DebugCompressionType::GNU)
+              .Default(llvm::DebugCompressionType::None);
+    }
+  }
+
+  Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
+  Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
+  Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
+  Opts.DwarfDebugProducer = Args.getLastArgValue(OPT_dwarf_debug_producer);
+  Opts.DebugCompilationDir = Args.getLastArgValue(OPT_fdebug_compilation_dir);
+  Opts.MainFileName = Args.getLastArgValue(OPT_main_file_name);
+
+  for (const auto &Arg : Args.getAllArgValues(OPT_fdebug_prefix_map_EQ))
+    Opts.DebugPrefixMap.insert(StringRef(Arg).split('='));
+
+  // Frontend Options
+  if (Args.hasArg(OPT_INPUT)) {
+    bool First = true;
+    for (const Arg *A : Args.filtered(OPT_INPUT)) {
+      if (First) {
+        Opts.InputFile = A->getValue();
+        First = false;
+      } else {
+        Diags.Report(diag::err_drv_unknown_argument) << A->getAsString(Args);
+        Success = false;
+      }
+    }
+  }
+  Opts.LLVMArgs = Args.getAllArgValues(OPT_mllvm);
+  Opts.OutputPath = Args.getLastArgValue(OPT_o);
+  Opts.SplitDwarfOutput = Args.getLastArgValue(OPT_split_dwarf_output);
+  if (Arg *A = Args.getLastArg(OPT_filetype)) {
+    StringRef Name = A->getValue();
+    unsigned OutputType = StringSwitch<unsigned>(Name)
+      .Case("asm", FT_Asm)
+      .Case("null", FT_Null)
+      .Case("obj", FT_Obj)
+      .Default(~0U);
+    if (OutputType == ~0U) {
+      Diags.Report(diag::err_drv_invalid_value) << A->getAsString(Args) << Name;
+      Success = false;
+    } else
+      Opts.OutputType = FileType(OutputType);
+  }
+  Opts.ShowHelp = Args.hasArg(OPT_help);
+  Opts.ShowVersion = Args.hasArg(OPT_version);
+
+  // Transliterate Options
+  Opts.OutputAsmVariant =
+      getLastArgIntValue(Args, OPT_output_asm_variant, 0, Diags);
+  Opts.ShowEncoding = Args.hasArg(OPT_show_encoding);
+  Opts.ShowInst = Args.hasArg(OPT_show_inst);
+
+  // Assemble Options
+  Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);
+  Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
+  Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
+  Opts.RelocationModel = Args.getLastArgValue(OPT_mrelocation_model, "pic");
+  Opts.TargetABI = Args.getLastArgValue(OPT_target_abi);
+  Opts.IncrementalLinkerCompatible =
+      Args.hasArg(OPT_mincremental_linker_compatible);
+  Opts.SymbolDefs = Args.getAllArgValues(OPT_defsym);
+
+  // EmbedBitcode Option. If -fembed-bitcode is enabled, set the flag.
+  // EmbedBitcode behaves the same for all embed options for assembly files.
+  if (auto *A = Args.getLastArg(OPT_fembed_bitcode_EQ)) {
+    Opts.EmbedBitcode = llvm::StringSwitch<unsigned>(A->getValue())
+                            .Case("all", 1)
+                            .Case("bitcode", 1)
+                            .Case("marker", 1)
+                            .Default(0);
+  }
+
+  return Success;
+}
+
+static std::unique_ptr<raw_fd_ostream>
+getOutputStream(StringRef Path, DiagnosticsEngine &Diags, bool Binary) {
+  // Make sure that the Out file gets unlinked from the disk if we get a
+  // SIGINT.
+  if (Path != "-")
+    sys::RemoveFileOnSignal(Path);
+
+  std::error_code EC;
+  auto Out = llvm::make_unique<raw_fd_ostream>(
+      Path, EC, (Binary ? sys::fs::F_None : sys::fs::F_Text));
+  if (EC) {
+    Diags.Report(diag::err_fe_unable_to_open_output) << Path << EC.message();
+    return nullptr;
+  }
+
+  return Out;
+}
+
+bool ExecuteAssembler(AssemblerInvocation &Opts, DiagnosticsEngine &Diags) {
+  // Get the target specific parser.
+  std::string Error;
+  const Target *TheTarget = TargetRegistry::lookupTarget(Opts.Triple, Error);
+  if (!TheTarget)
+    return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
+
+  ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
+      MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
+
+  if (std::error_code EC = Buffer.getError()) {
+    Error = EC.message();
+    return Diags.Report(diag::err_fe_error_reading) << Opts.InputFile;
+  }
+
+  SourceMgr SrcMgr;
+
+  // Tell SrcMgr about this buffer, which is what the parser will pick up.
+  unsigned BufferIndex = SrcMgr.AddNewSourceBuffer(std::move(*Buffer), SMLoc());
+
+  // Record the location of the include directories so that the lexer can find
+  // it later.
+  SrcMgr.setIncludeDirs(Opts.IncludePaths);
+
+  std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(Opts.Triple));
+  assert(MRI && "Unable to create target register info!");
+
+  std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, Opts.Triple));
+  assert(MAI && "Unable to create target asm info!");
+
+  // Ensure MCAsmInfo initialization occurs before any use, otherwise sections
+  // may be created with a combination of default and explicit settings.
+  MAI->setCompressDebugSections(Opts.CompressDebugSections);
+
+  MAI->setRelaxELFRelocations(Opts.RelaxELFRelocations);
+
+  bool IsBinary = Opts.OutputType == AssemblerInvocation::FT_Obj;
+  if (Opts.OutputPath.empty())
+    Opts.OutputPath = "-";
+  std::unique_ptr<raw_fd_ostream> FDOS =
+      getOutputStream(Opts.OutputPath, Diags, IsBinary);
+  if (!FDOS)
+    return true;
+  std::unique_ptr<raw_fd_ostream> DwoOS;
+  if (!Opts.SplitDwarfOutput.empty())
+    DwoOS = getOutputStream(Opts.SplitDwarfOutput, Diags, IsBinary);
+
+  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
+  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
+  std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
+
+  MCContext Ctx(MAI.get(), MRI.get(), MOFI.get(), &SrcMgr);
+
+  bool PIC = false;
+  if (Opts.RelocationModel == "static") {
+    PIC = false;
+  } else if (Opts.RelocationModel == "pic") {
+    PIC = true;
+  } else {
+    assert(Opts.RelocationModel == "dynamic-no-pic" &&
+           "Invalid PIC model!");
+    PIC = false;
+  }
+
+  MOFI->InitMCObjectFileInfo(Triple(Opts.Triple), PIC, Ctx);
+  if (Opts.SaveTemporaryLabels)
+    Ctx.setAllowTemporaryLabels(false);
+  if (Opts.GenDwarfForAssembly)
+    Ctx.setGenDwarfForAssembly(true);
+  if (!Opts.DwarfDebugFlags.empty())
+    Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
+  if (!Opts.DwarfDebugProducer.empty())
+    Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));
+  if (!Opts.DebugCompilationDir.empty())
+    Ctx.setCompilationDir(Opts.DebugCompilationDir);
+  else {
+    // If no compilation dir is set, try to use the current directory.
+    SmallString<128> CWD;
+    if (!sys::fs::current_path(CWD))
+      Ctx.setCompilationDir(CWD);
+  }
+  if (!Opts.DebugPrefixMap.empty())
+    for (const auto &KV : Opts.DebugPrefixMap)
+      Ctx.addDebugPrefixMapEntry(KV.first, KV.second);
+  if (!Opts.MainFileName.empty())
+    Ctx.setMainFileName(StringRef(Opts.MainFileName));
+  Ctx.setDwarfVersion(Opts.DwarfVersion);
+  if (Opts.GenDwarfForAssembly)
+    Ctx.setGenDwarfRootFile(Opts.InputFile,
+                            SrcMgr.getMemoryBuffer(BufferIndex)->getBuffer());
+
+  // Build up the feature string from the target feature list.
+  std::string FS;
+  if (!Opts.Features.empty()) {
+    FS = Opts.Features[0];
+    for (unsigned i = 1, e = Opts.Features.size(); i != e; ++i)
+      FS += "," + Opts.Features[i];
+  }
+
+  std::unique_ptr<MCStreamer> Str;
+
+  std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
+  std::unique_ptr<MCSubtargetInfo> STI(
+      TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
+
+  raw_pwrite_stream *Out = FDOS.get();
+  std::unique_ptr<buffer_ostream> BOS;
+
+  MCTargetOptions MCOptions;
+  MCOptions.ABIName = Opts.TargetABI;
+
+  // FIXME: There is a bit of code duplication with addPassesToEmitFile.
+  if (Opts.OutputType == AssemblerInvocation::FT_Asm) {
+    MCInstPrinter *IP = TheTarget->createMCInstPrinter(
+        llvm::Triple(Opts.Triple), Opts.OutputAsmVariant, *MAI, *MCII, *MRI);
+
+    std::unique_ptr<MCCodeEmitter> CE;
+    if (Opts.ShowEncoding)
+      CE.reset(TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
+    std::unique_ptr<MCAsmBackend> MAB(
+        TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
+
+    auto FOut = llvm::make_unique<formatted_raw_ostream>(*Out);
+    Str.reset(TheTarget->createAsmStreamer(
+        Ctx, std::move(FOut), /*asmverbose*/ true,
+        /*useDwarfDirectory*/ true, IP, std::move(CE), std::move(MAB),
+        Opts.ShowInst));
+  } else if (Opts.OutputType == AssemblerInvocation::FT_Null) {
+    Str.reset(createNullStreamer(Ctx));
+  } else {
+    assert(Opts.OutputType == AssemblerInvocation::FT_Obj &&
+           "Invalid file type!");
+    if (!FDOS->supportsSeeking()) {
+      BOS = make_unique<buffer_ostream>(*FDOS);
+      Out = BOS.get();
+    }
+
+    std::unique_ptr<MCCodeEmitter> CE(
+        TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
+    std::unique_ptr<MCAsmBackend> MAB(
+        TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions));
+    std::unique_ptr<MCObjectWriter> OW =
+        DwoOS ? MAB->createDwoObjectWriter(*Out, *DwoOS)
+              : MAB->createObjectWriter(*Out);
+
+    Triple T(Opts.Triple);
+    Str.reset(TheTarget->createMCObjectStreamer(
+        T, Ctx, std::move(MAB), std::move(OW), std::move(CE), *STI,
+        Opts.RelaxAll, Opts.IncrementalLinkerCompatible,
+        /*DWARFMustBeAtTheEnd*/ true));
+    Str.get()->InitSections(Opts.NoExecStack);
+  }
+
+  // When -fembed-bitcode is passed to clang_as, a 1-byte marker
+  // is emitted in __LLVM,__asm section if the object file is MachO format.
+  if (Opts.EmbedBitcode && Ctx.getObjectFileInfo()->getObjectFileType() ==
+                               MCObjectFileInfo::IsMachO) {
+    MCSection *AsmLabel = Ctx.getMachOSection(
+        "__LLVM", "__asm", MachO::S_REGULAR, 4, SectionKind::getReadOnly());
+    Str.get()->SwitchSection(AsmLabel);
+    Str.get()->EmitZeros(1);
+  }
+
+  // Assembly to object compilation should leverage assembly info.
+  Str->setUseAssemblerInfoForParsing(true);
+
+  bool Failed = false;
+
+  std::unique_ptr<MCAsmParser> Parser(
+      createMCAsmParser(SrcMgr, Ctx, *Str.get(), *MAI));
+
+  // FIXME: init MCTargetOptions from sanitizer flags here.
+  std::unique_ptr<MCTargetAsmParser> TAP(
+      TheTarget->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
+  if (!TAP)
+    Failed = Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
+
+  // Set values for symbols, if any.
+  for (auto &S : Opts.SymbolDefs) {
+    auto Pair = StringRef(S).split('=');
+    auto Sym = Pair.first;
+    auto Val = Pair.second;
+    int64_t Value;
+    // We have already error checked this in the driver.
+    Val.getAsInteger(0, Value);
+    Ctx.setSymbolValue(Parser->getStreamer(), Sym, Value);
+  }
+
+  if (!Failed) {
+    Parser->setTargetParser(*TAP.get());
+    Failed = Parser->Run(Opts.NoInitialTextSection);
+  }
+
+  // Close Streamer first.
+  // It might have a reference to the output stream.
+  Str.reset();
+  // Close the output stream early.
+  BOS.reset();
+  FDOS.reset();
+
+  // Delete output file if there were errors.
+  if (Failed) {
+    if (Opts.OutputPath != "-")
+      sys::fs::remove(Opts.OutputPath);
+    if (!Opts.SplitDwarfOutput.empty() && Opts.SplitDwarfOutput != "-")
+      sys::fs::remove(Opts.SplitDwarfOutput);
+  }
+
+  return Failed;
+}
+
+static void LLVMErrorHandler(void *UserData, const std::string &Message,
+                             bool GenCrashDiag) {
+  DiagnosticsEngine &Diags = *static_cast<DiagnosticsEngine*>(UserData);
+
+  Diags.Report(diag::err_fe_error_backend) << Message;
+
+  // We cannot recover from llvm errors.
+  exit(1);
+}
+
+int cc1as_main(ArrayRef<const char *> Argv, const char *Argv0, void *MainAddr) {
+  // Initialize targets and assembly printers/parsers.
+  InitializeAllTargetInfos();
+  InitializeAllTargetMCs();
+  InitializeAllAsmParsers();
+
+  // Construct our diagnostic client.
+  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
+  TextDiagnosticPrinter *DiagClient
+    = new TextDiagnosticPrinter(errs(), &*DiagOpts);
+  DiagClient->setPrefix("clang -cc1as");
+  IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+  DiagnosticsEngine Diags(DiagID, &*DiagOpts, DiagClient);
+
+  // Set an error handler, so that any LLVM backend diagnostics go through our
+  // error handler.
+  ScopedFatalErrorHandler FatalErrorHandler
+    (LLVMErrorHandler, static_cast<void*>(&Diags));
+
+  // Parse the arguments.
+  AssemblerInvocation Asm;
+  if (!AssemblerInvocation::CreateFromArgs(Asm, Argv, Diags))
+    return 1;
+
+  if (Asm.ShowHelp) {
+    std::unique_ptr<OptTable> Opts(driver::createDriverOptTable());
+    Opts->PrintHelp(llvm::outs(), "clang -cc1as [options] file...",
+                    "Clang Integrated Assembler",
+                    /*Include=*/driver::options::CC1AsOption, /*Exclude=*/0,
+                    /*ShowAllAliases=*/false);
+    return 0;
+  }
+
+  // Honor -version.
+  //
+  // FIXME: Use a better -version message?
+  if (Asm.ShowVersion) {
+    llvm::cl::PrintVersionMessage();
+    return 0;
+  }
+
+  // Honor -mllvm.
+  //
+  // FIXME: Remove this, one day.
+  if (!Asm.LLVMArgs.empty()) {
+    unsigned NumArgs = Asm.LLVMArgs.size();
+    auto Args = llvm::make_unique<const char*[]>(NumArgs + 2);
+    Args[0] = "clang (LLVM option parsing)";
+    for (unsigned i = 0; i != NumArgs; ++i)
+      Args[i + 1] = Asm.LLVMArgs[i].c_str();
+    Args[NumArgs + 1] = nullptr;
+    llvm::cl::ParseCommandLineOptions(NumArgs + 1, Args.get());
+  }
+
+  // Execute the invocation, unless there were parsing errors.
+  bool Failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
+
+  // If any timers were active but haven't been destroyed yet, print their
+  // results now.
+  TimerGroup::printAll(errs());
+
+  return !!Failed;
+}

builder/cc1as.h

@@ -0,0 +1,120 @@
+//===-- cc1as.h - Clang Assembler  ----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This is the entry point to the clang -cc1as functionality, which implements
+// the direct interface to the LLVM MC based assembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/ArrayRef.h"
+
+/// Helper class for representing a single invocation of the assembler.
+struct AssemblerInvocation {
+  /// @name Target Options
+  /// @{
+
+  /// The name of the target triple to assemble for.
+  std::string Triple;
+
+  /// If given, the name of the target CPU to determine which instructions
+  /// are legal.
+  std::string CPU;
+
+  /// The list of target specific features to enable or disable -- this should
+  /// be a list of strings starting with '+' or '-'.
+  std::vector<std::string> Features;
+
+  /// The list of symbol definitions.
+  std::vector<std::string> SymbolDefs;
+
+  /// @}
+  /// @name Language Options
+  /// @{
+
+  std::vector<std::string> IncludePaths;
+  unsigned NoInitialTextSection : 1;
+  unsigned SaveTemporaryLabels : 1;
+  unsigned GenDwarfForAssembly : 1;
+  unsigned RelaxELFRelocations : 1;
+  unsigned DwarfVersion;
+  std::string DwarfDebugFlags;
+  std::string DwarfDebugProducer;
+  std::string DebugCompilationDir;
+  std::map<const std::string, const std::string> DebugPrefixMap;
+  llvm::DebugCompressionType CompressDebugSections =
+      llvm::DebugCompressionType::None;
+  std::string MainFileName;
+  std::string SplitDwarfOutput;
+
+  /// @}
+  /// @name Frontend Options
+  /// @{
+
+  std::string InputFile;
+  std::vector<std::string> LLVMArgs;
+  std::string OutputPath;
+  enum FileType {
+    FT_Asm,  ///< Assembly (.s) output, transliterate mode.
+    FT_Null, ///< No output, for timing purposes.
+    FT_Obj   ///< Object file output.
+  };
+  FileType OutputType;
+  unsigned ShowHelp : 1;
+  unsigned ShowVersion : 1;
+
+  /// @}
+  /// @name Transliterate Options
+  /// @{
+
+  unsigned OutputAsmVariant;
+  unsigned ShowEncoding : 1;
+  unsigned ShowInst : 1;
+
+  /// @}
+  /// @name Assembler Options
+  /// @{
+
+  unsigned RelaxAll : 1;
+  unsigned NoExecStack : 1;
+  unsigned FatalWarnings : 1;
+  unsigned IncrementalLinkerCompatible : 1;
+  unsigned EmbedBitcode : 1;
+
+  /// The name of the relocation model to use.
+  std::string RelocationModel;
+
+  /// The ABI targeted by the backend. Specified using -target-abi. Empty
+  /// otherwise.
+  std::string TargetABI;
+
+  /// @}
+
+public:
+  AssemblerInvocation() {
+    Triple = "";
+    NoInitialTextSection = 0;
+    InputFile = "-";
+    OutputPath = "-";
+    OutputType = FT_Asm;
+    OutputAsmVariant = 0;
+    ShowInst = 0;
+    ShowEncoding = 0;
+    RelaxAll = 0;
+    NoExecStack = 0;
+    FatalWarnings = 0;
+    IncrementalLinkerCompatible = 0;
+    DwarfVersion = 0;
+    EmbedBitcode = 0;
+  }
+
+  static bool CreateFromArgs(AssemblerInvocation &Res,
+                             ArrayRef<const char *> Argv,
+                             DiagnosticsEngine &Diags);
+};
+
+bool ExecuteAssembler(AssemblerInvocation &Opts, DiagnosticsEngine &Diags);

builder/clang.cpp

@@ -0,0 +1,97 @@
+// +build byollvm
+
+#include <clang/Basic/DiagnosticOptions.h>
+#include <clang/CodeGen/CodeGenAction.h>
+#include <clang/Driver/Compilation.h>
+#include <clang/Driver/Driver.h>
+#include <clang/Frontend/CompilerInstance.h>
+#include <clang/Frontend/CompilerInvocation.h>
+#include <clang/Frontend/FrontendDiagnostic.h>
+#include <clang/Frontend/TextDiagnosticPrinter.h>
+#include <clang/FrontendTool/Utils.h>
+#include <llvm/ADT/IntrusiveRefCntPtr.h>
+#include <llvm/Option/Option.h>
+
+using namespace llvm;
+using namespace clang;
+
+#include "cc1as.h"
+
+// This file provides C wrappers for the builtin tools cc1 and cc1as
+// provided by Clang, and calls them as the driver would call them.
+
+extern "C" {
+
+bool tinygo_clang_driver(int argc, char **argv) {
+	std::vector<const char*> args(argv, argv + argc);
+
+	// The compiler invocation needs a DiagnosticsEngine so it can report problems
+	llvm::IntrusiveRefCntPtr<clang::DiagnosticOptions> DiagOpts = new clang::DiagnosticOptions();
+	clang::TextDiagnosticPrinter DiagnosticPrinter(llvm::errs(), &*DiagOpts);
+	clang::DiagnosticsEngine Diags(llvm::IntrusiveRefCntPtr<clang::DiagnosticIDs>(new clang::DiagnosticIDs()), &*DiagOpts, &DiagnosticPrinter, false);
+
+	// Create the clang driver
+	clang::driver::Driver TheDriver(args[0], llvm::sys::getDefaultTargetTriple(), Diags);
+
+	// Create the set of actions to perform
+	std::unique_ptr<clang::driver::Compilation> C(TheDriver.BuildCompilation(args));
+	if (!C) {
+		return false;
+	}
+	const clang::driver::JobList &Jobs = C->getJobs();
+
+	// There may be more than one job, for example for .S files
+	// (preprocessor + assembler).
+	for (auto Cmd : Jobs) {
+		// Select the tool: cc1 or cc1as.
+		const llvm::opt::ArgStringList &CCArgs = Cmd.getArguments();
+
+		if (strcmp(*CCArgs.data(), "-cc1") == 0) {
+			// This is the C frontend.
+			// Initialize a compiler invocation object from the clang (-cc1) arguments.
+			std::unique_ptr<clang::CompilerInstance> Clang(new clang::CompilerInstance());
+			bool success = clang::CompilerInvocation::CreateFromArgs(
+					Clang->getInvocation(),
+					const_cast<const char **>(CCArgs.data()),
+					const_cast<const char **>(CCArgs.data()) + CCArgs.size(),
+					Diags);
+			if (!success) {
+				return false;
+			}
+
+			// Create the actual diagnostics engine.
+			Clang->createDiagnostics();
+			if (!Clang->hasDiagnostics()) {
+				return false;
+			}
+
+			// Execute the frontend actions.
+			success = ExecuteCompilerInvocation(Clang.get());
+			if (!success) {
+				return false;
+			}
+
+		} else if (strcmp(*CCArgs.data(), "-cc1as") == 0) {
+			// This is the assembler frontend. Parse the arguments.
+			AssemblerInvocation Asm;
+			if (!AssemblerInvocation::CreateFromArgs(Asm, llvm::ArrayRef<const char*>(CCArgs).slice(1), Diags))
+				return false;
+
+			// Execute the invocation, unless there were parsing errors.
+			bool failed = Diags.hasErrorOccurred() || ExecuteAssembler(Asm, Diags);
+			if (failed) {
+				return false;
+			}
+
+		} else {
+			// Unknown tool, print the tool and exit.
+			fprintf(stderr, "unknown tool: %s\n", *CCArgs.data());
+			return false;
+		}
+	}
+
+	// Commands executed successfully.
+	return true;
+}
+
+} // extern "C"

builder/commands.go

@@ -34,6 +34,12 @@ func init() {
 		commands["ld.lld"] = append(commands["ld.lld"], "lld", "C:\\Program Files\\LLVM\\bin\\lld.exe")
 		commands["wasm-ld"] = append(commands["wasm-ld"], "C:\\Program Files\\LLVM\\bin\\wasm-ld.exe")
 	}
+	// Add the path to the llvm90 installed from ports
+	if runtime.GOOS == "freebsd" {
+		commands["clang"] = append(commands["clang"], "/usr/local/llvm90/bin/clang-9")
+		commands["ld.lld"] = append(commands["ld.lld"], "/usr/local/llvm90/bin/ld.lld")
+		commands["wasm-ld"] = append(commands["wasm-ld"], "/usr/local/llvm90/bin/wasm-ld")
+	}
 }
 
 func execCommand(cmdNames []string, args ...string) error {

builder/compiler-builtin.go

@@ -0,0 +1,60 @@
+// +build byollvm
+
+package builder
+
+import (
+	"errors"
+	"os"
+	"os/exec"
+	"unsafe"
+
+	"github.com/tinygo-org/tinygo/goenv"
+)
+
+/*
+#cgo CXXFLAGS: -fno-rtti
+#include <stdbool.h>
+#include <stdlib.h>
+bool tinygo_clang_driver(int argc, char **argv);
+*/
+import "C"
+
+// runCCompiler invokes a C compiler with the given arguments.
+//
+// This version invokes the built-in Clang when trying to run the Clang compiler.
+func runCCompiler(command string, flags ...string) error {
+	switch command {
+	case "clang":
+		// Compile this with the internal Clang compiler.
+		headerPath := getClangHeaderPath(goenv.Get("TINYGOROOT"))
+		if headerPath == "" {
+			return errors.New("could not locate Clang headers")
+		}
+		flags = append(flags, "-I"+headerPath)
+		flags = append([]string{"tinygo:" + command}, flags...)
+		var cflag *C.char
+		buf := C.calloc(C.size_t(len(flags)), C.size_t(unsafe.Sizeof(cflag)))
+		cflags := (*[1 << 10]*C.char)(unsafe.Pointer(buf))[:len(flags):len(flags)]
+		for i, flag := range flags {
+			cflag := C.CString(flag)
+			cflags[i] = cflag
+			defer C.free(unsafe.Pointer(cflag))
+		}
+		ok := C.tinygo_clang_driver(C.int(len(flags)), (**C.char)(buf))
+		if !ok {
+			return errors.New("failed to compile using built-in clang")
+		}
+		return nil
+	default:
+		// Running some other compiler. Maybe it has been defined in the
+		// commands map (unlikely).
+		if cmdNames, ok := commands[command]; ok {
+			return execCommand(cmdNames, flags...)
+		}
+		// Alternatively, run the compiler directly.
+		cmd := exec.Command(command, flags...)
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		return cmd.Run()
+	}
+}

builder/compiler-external.go

@@ -0,0 +1,24 @@
+// +build !byollvm
+
+package builder
+
+// This file provides a way to a C compiler as an external command. See also:
+// clang-external.go
+
+import (
+	"os"
+	"os/exec"
+)
+
+// runCCompiler invokes a C compiler with the given arguments.
+//
+// This version always runs the compiler as an external command.
+func runCCompiler(command string, flags ...string) error {
+	if cmdNames, ok := commands[command]; ok {
+		return execCommand(cmdNames, flags...)
+	}
+	cmd := exec.Command(command, flags...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	return cmd.Run()
+}

builder/env.go

@@ -71,7 +71,7 @@ func GorootVersionString(goroot string) (string, error) {
 // various ways.
 func getClangHeaderPath(TINYGOROOT string) string {
 	// Check whether we're running from the source directory.
-	path := filepath.Join(TINYGOROOT, "llvm", "tools", "clang", "lib", "Headers")
+	path := filepath.Join(TINYGOROOT, "llvm-project", "clang", "lib", "Headers")
 	if _, err := os.Stat(path); !os.IsNotExist(err) {
 		return path
 	}

builder/error.go

@@ -12,6 +12,20 @@ func (e *MultiError) Error() string {
 	return e.Errs[0].Error()
 }
 
+// newMultiError returns a *MultiError if there is more than one error, or
+// returns that error directly when there is only one. Passing an empty slice
+// will lead to a panic.
+func newMultiError(errs []error) error {
+	switch len(errs) {
+	case 0:
+		panic("attempted to create empty MultiError")
+	case 1:
+		return errs[0]
+	default:
+		return &MultiError{errs}
+	}
+}
+
 // commandError is an error type to wrap os/exec.Command errors. This provides
 // some more information regarding what went wrong while running a command.
 type commandError struct {

cgo/cgo_test.go

@@ -22,11 +22,9 @@ var flagUpdate = flag.Bool("update", false, "Update images based on test output.
 func TestCGo(t *testing.T) {
 	var cflags = []string{"--target=armv6m-none-eabi"}
 
-	for _, name := range []string{"basic", "errors", "types", "flags"} {
+	for _, name := range []string{"basic", "errors", "types", "flags", "const"} {
 		name := name // avoid a race condition
 		t.Run(name, func(t *testing.T) {
-			t.Parallel()
-
 			// Read the AST in memory.
 			path := filepath.Join("testdata", name+".go")
 			fset := token.NewFileSet()

cgo/const.go

@@ -52,6 +52,13 @@ func parseConstExpr(t *tokenizer) (ast.Expr, *scanner.Error) {
 		}
 		t.Next()
 		return expr, nil
+	case token.IDENT:
+		expr := &ast.Ident{
+			NamePos: t.pos,
+			Name:    "C." + t.value,
+		}
+		t.Next()
+		return expr, nil
 	case token.EOF:
 		return nil, &scanner.Error{
 			Pos: t.fset.Position(t.pos),
@@ -133,8 +140,10 @@ func (t *tokenizer) Next() {
 				if c == '.' {
 					hasDot = true
 				}
-				if (c >= '0' && c <= '9') || c == '.' || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') {
+				if c >= '0' && c <= '9' || c == '.' || c == '_' || c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' {
 					tokenLen = i + 1
+				} else {
+					break
 				}
 			}
 			t.value = t.buf[:tokenLen]
@@ -150,6 +159,21 @@ func (t *tokenizer) Next() {
 				t.value = strings.TrimRight(t.value, "uUlL")
 			}
 			return
+		case c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z' || c == '_':
+			// Identifier. Find all remaining tokens that are part of this
+			// identifier.
+			tokenLen := len(t.buf)
+			for i, c := range t.buf {
+				if c >= '0' && c <= '9' || c >= 'A' && c <= 'Z' || c >= 'a' && c <= 'z' || c == '_' {
+					tokenLen = i + 1
+				} else {
+					break
+				}
+			}
+			t.value = t.buf[:tokenLen]
+			t.buf = t.buf[tokenLen:]
+			t.token = token.IDENT
+			return
 		case c == '"':
 			// String constant. Find the first '"' character that is not
 			// preceded by a backslash.

cgo/const_test.go

@@ -21,7 +21,7 @@ func TestParseConst(t *testing.T) {
 		{`5)`, `error: 1:2: unexpected token )`},
 		{"  \t)", `error: 1:4: unexpected token )`},
 		{`5.8f`, `5.8`},
-		{`foo`, `error: 1:1: unexpected token ILLEGAL`}, // identifiers unimplemented
+		{`foo`, `C.foo`},
 		{``, `error: 1:1: empty constant`}, // empty constants not allowed in Go
 		{`"foo"`, `"foo"`},
 		{`"a\\n"`, `"a\\n"`},
@@ -30,6 +30,7 @@ func TestParseConst(t *testing.T) {
 		{`'a'`, `'a'`},
 		{`0b10`, `0b10`},
 		{`0x1234_5678`, `0x1234_5678`},
+		{`5 5`, `error: 1:3: unexpected token INT`}, // test for a bugfix
 	} {
 		fset := token.NewFileSet()
 		startPos := fset.AddFile("", -1, 1000).Pos(0)

cgo/libclang_config.go

@@ -5,7 +5,9 @@ package cgo
 /*
 #cgo linux  CFLAGS: -I/usr/lib/llvm-9/include
 #cgo darwin CFLAGS: -I/usr/local/opt/llvm@9/include
+#cgo freebsd CFLAGS: -I/usr/local/llvm90/include
 #cgo linux  LDFLAGS: -L/usr/lib/llvm-9/lib -lclang
 #cgo darwin LDFLAGS: -L/usr/local/opt/llvm@9/lib -lclang -lffi
+#cgo freebsd LDFLAGS: -L/usr/local/llvm90/lib -lclang
 */
 import "C"

cgo/testdata/const.go

@@ -0,0 +1,12 @@
+package main
+
+/*
+#define foo 3
+#define bar foo
+*/
+import "C"
+
+const (
+	Foo = C.foo
+	Bar = C.bar
+)

cgo/testdata/const.out.go

@@ -0,0 +1,29 @@
+package main
+
+import "unsafe"
+
+var _ unsafe.Pointer
+
+const C.bar = C.foo
+const C.foo = 3
+
+type C.int16_t = int16
+type C.int32_t = int32
+type C.int64_t = int64
+type C.int8_t = int8
+type C.uint16_t = uint16
+type C.uint32_t = uint32
+type C.uint64_t = uint64
+type C.uint8_t = uint8
+type C.uintptr_t = uintptr
+type C.char uint8
+type C.int int32
+type C.long int32
+type C.longlong int64
+type C.schar int8
+type C.short int16
+type C.uchar uint8
+type C.uint uint32
+type C.ulong uint32
+type C.ulonglong uint64
+type C.ushort uint16

compiler/check.go

@@ -98,76 +98,75 @@ func (c *Compiler) checkValue(v llvm.Value, types map[llvm.Type]struct{}, specia
 func (c *Compiler) checkInstruction(inst llvm.Value, types map[llvm.Type]struct{}, specials map[llvm.TypeKind]llvm.Type) error {
 	// check value properties
 	if err := c.checkValue(inst, types, specials); err != nil {
-		return fmt.Errorf("failed to validate value of instruction %q: %s", inst.Name(), err.Error())
+		return errorAt(inst, err.Error())
 	}
 
 	// check operands
 	for i := 0; i < inst.OperandsCount(); i++ {
 		if err := c.checkValue(inst.Operand(i), types, specials); err != nil {
-			return fmt.Errorf("failed to validate argument %d of instruction %q: %s", i, inst.Name(), err.Error())
+			return errorAt(inst, fmt.Sprintf("failed to validate operand %d of instruction %q: %s", i, inst.Name(), err.Error()))
 		}
 	}
 
 	return nil
 }
 
-func (c *Compiler) checkBasicBlock(bb llvm.BasicBlock, types map[llvm.Type]struct{}, specials map[llvm.TypeKind]llvm.Type) error {
+func (c *Compiler) checkBasicBlock(bb llvm.BasicBlock, types map[llvm.Type]struct{}, specials map[llvm.TypeKind]llvm.Type) []error {
 	// check basic block value and type
+	var errs []error
 	if err := c.checkValue(bb.AsValue(), types, specials); err != nil {
-		return fmt.Errorf("failed to validate value of basic block %s: %s", bb.AsValue().Name(), err.Error())
+		errs = append(errs, errorAt(bb.Parent(), fmt.Sprintf("failed to validate value of basic block %s: %v", bb.AsValue().Name(), err)))
 	}
 
 	// check instructions
 	for inst := bb.FirstInstruction(); !inst.IsNil(); inst = llvm.NextInstruction(inst) {
 		if err := c.checkInstruction(inst, types, specials); err != nil {
-			return fmt.Errorf("failed to validate basic block %q: %s", bb.AsValue().Name(), err.Error())
+			errs = append(errs, err)
 		}
 	}
 
-	return nil
+	return errs
 }
 
-func (c *Compiler) checkFunction(fn llvm.Value, types map[llvm.Type]struct{}, specials map[llvm.TypeKind]llvm.Type) error {
+func (c *Compiler) checkFunction(fn llvm.Value, types map[llvm.Type]struct{}, specials map[llvm.TypeKind]llvm.Type) []error {
 	// check function value and type
+	var errs []error
 	if err := c.checkValue(fn, types, specials); err != nil {
-		return fmt.Errorf("failed to validate value of function %s: %s", fn.Name(), err.Error())
+		errs = append(errs, fmt.Errorf("failed to validate value of function %s: %s", fn.Name(), err.Error()))
 	}
 
 	// check basic blocks
 	for bb := fn.FirstBasicBlock(); !bb.IsNil(); bb = llvm.NextBasicBlock(bb) {
-		if err := c.checkBasicBlock(bb, types, specials); err != nil {
+		errs = append(errs, c.checkBasicBlock(bb, types, specials)...)
-			return fmt.Errorf("failed to validate basic block of function %s: %s", fn.Name(), err.Error())
-		}
 	}
 
-	return nil
+	return errs
 }
 
-func (c *Compiler) checkModule() error {
+func (c *Compiler) checkModule() []error {
 	// check for any context mismatches
+	var errs []error
 	switch {
 	case c.mod.Context() == c.ctx:
 		// this is correct
 	case c.mod.Context() == llvm.GlobalContext():
 		// somewhere we accidentally used the global context instead of a real context
-		return errors.New("module uses global context")
+		errs = append(errs, errors.New("module uses global context"))
 	default:
 		// we used some other context by accident
-		return fmt.Errorf("module uses context %v instead of the main context %v", c.mod.Context(), c.ctx)
+		errs = append(errs, fmt.Errorf("module uses context %v instead of the main context %v", c.mod.Context(), c.ctx))
 	}
 
 	types := map[llvm.Type]struct{}{}
 	specials := map[llvm.TypeKind]llvm.Type{}
 	for fn := c.mod.FirstFunction(); !fn.IsNil(); fn = llvm.NextFunction(fn) {
-		if err := c.checkFunction(fn, types, specials); err != nil {
+		errs = append(errs, c.checkFunction(fn, types, specials)...)
-			return err
-		}
 	}
 	for g := c.mod.FirstGlobal(); !g.IsNil(); g = llvm.NextGlobal(g) {
 		if err := c.checkValue(g, types, specials); err != nil {
-			return fmt.Errorf("failed to verify global %s of module: %s", g.Name(), err.Error())
+			errs = append(errs, fmt.Errorf("failed to verify global %s of module: %s", g.Name(), err.Error()))
 		}
 	}
 
-	return nil
+	return errs
 }

compiler/compiler.go

@@ -217,7 +217,7 @@ func (c *Compiler) Compile(mainPath string) []error {
 				path = path[len(tinygoPath+"/src/"):]
 			}
 			switch path {
-			case "machine", "os", "reflect", "runtime", "runtime/volatile", "sync", "testing", "internal/reflectlite":
+			case "machine", "os", "reflect", "runtime", "runtime/interrupt", "runtime/volatile", "sync", "testing", "internal/reflectlite":
 				return path
 			default:
 				if strings.HasPrefix(path, "device/") || strings.HasPrefix(path, "examples/") {
@@ -251,13 +251,17 @@ func (c *Compiler) Compile(mainPath string) []error {
 			return []error{err}
 		}
 	} else {
-		_, err = lprogram.Import(mainPath, wd)
+		_, err = lprogram.Import(mainPath, wd, token.Position{
+			Filename: "build command-line-arguments",
+		})
 		if err != nil {
 			return []error{err}
 		}
 	}
 
-	_, err = lprogram.Import("runtime", "")
+	_, err = lprogram.Import("runtime", "", token.Position{
+		Filename: "build default import",
+	})
 	if err != nil {
 		return []error{err}
 	}
@@ -767,14 +771,6 @@ func (c *Compiler) attachDebugInfo(f *ir.Function) llvm.Metadata {
 }
 
 func (c *Compiler) attachDebugInfoRaw(f *ir.Function, llvmFn llvm.Value, suffix, filename string, line int) llvm.Metadata {
-	if _, ok := c.difiles[filename]; !ok {
-		dir, file := filepath.Split(filename)
-		if dir != "" {
-			dir = dir[:len(dir)-1]
-		}
-		c.difiles[filename] = c.dibuilder.CreateFile(file, dir)
-	}
-
 	// Debug info for this function.
 	diparams := make([]llvm.Metadata, 0, len(f.Params))
 	for _, param := range f.Params {
@@ -788,7 +784,7 @@ func (c *Compiler) attachDebugInfoRaw(f *ir.Function, llvmFn llvm.Value, suffix,
 	difunc := c.dibuilder.CreateFunction(c.difiles[filename], llvm.DIFunction{
 		Name:         f.RelString(nil) + suffix,
 		LinkageName:  f.LinkName() + suffix,
-		File:         c.difiles[filename],
+		File:         c.getDIFile(filename),
 		Line:         line,
 		Type:         diFuncType,
 		LocalToUnit:  true,
@@ -801,21 +797,37 @@ func (c *Compiler) attachDebugInfoRaw(f *ir.Function, llvmFn llvm.Value, suffix,
 	return difunc
 }
 
+// getDIFile returns a DIFile metadata node for the given filename. It tries to
+// use one that was already created, otherwise it falls back to creating a new
+// one.
+func (c *Compiler) getDIFile(filename string) llvm.Metadata {
+	if _, ok := c.difiles[filename]; !ok {
+		dir, file := filepath.Split(filename)
+		if dir != "" {
+			dir = dir[:len(dir)-1]
+		}
+		c.difiles[filename] = c.dibuilder.CreateFile(file, dir)
+	}
+	return c.difiles[filename]
+}
+
 func (c *Compiler) parseFunc(frame *Frame) {
 	if c.DumpSSA() {
 		fmt.Printf("\nfunc %s:\n", frame.fn.Function)
 	}
 	if !frame.fn.LLVMFn.IsDeclaration() {
-		c.addError(frame.fn.Pos(), "function is already defined:"+frame.fn.LLVMFn.Name())
+		errValue := frame.fn.LLVMFn.Name() + " redeclared in this program"
+		fnPos := getPosition(frame.fn.LLVMFn)
+		if fnPos.IsValid() {
+			errValue += "\n\tprevious declaration at " + fnPos.String()
+		}
+		c.addError(frame.fn.Pos(), errValue)
 		return
 	}
 	if !frame.fn.IsExported() {
 		frame.fn.LLVMFn.SetLinkage(llvm.InternalLinkage)
 		frame.fn.LLVMFn.SetUnnamedAddr(true)
 	}
-	if frame.fn.IsInterrupt() && strings.HasPrefix(c.Triple(), "avr") {
-		frame.fn.LLVMFn.SetFunctionCallConv(85) // CallingConv::AVR_SIGNAL
-	}
 
 	// Some functions have a pragma controlling the inlining level.
 	switch frame.fn.Inline() {
@@ -1297,6 +1309,8 @@ func (c *Compiler) parseCall(frame *Frame, instr *ssa.CallCommon) (llvm.Value, e
 			return c.emitVolatileLoad(frame, instr)
 		case strings.HasPrefix(name, "runtime/volatile.Store"):
 			return c.emitVolatileStore(frame, instr)
+		case name == "runtime/interrupt.New" && len(fn.Blocks) == 0:
+			return c.emitInterruptGlobal(frame, instr)
 		}
 
 		targetFunc := c.ir.GetFunction(fn)

compiler/defer.go

@@ -14,6 +14,7 @@ package compiler
 //     frames.
 
 import (
+	"github.com/tinygo-org/tinygo/compiler/llvmutil"
 	"github.com/tinygo-org/tinygo/ir"
 	"golang.org/x/tools/go/ssa"
 	"tinygo.org/x/go-llvm"
@@ -34,6 +35,40 @@ func (c *Compiler) deferInitFunc(frame *Frame) {
 	c.builder.CreateStore(llvm.ConstPointerNull(deferType), frame.deferPtr)
 }
 
+// isInLoop checks if there is a path from a basic block to itself.
+func isInLoop(start *ssa.BasicBlock) bool {
+	// Use a breadth-first search to scan backwards through the block graph.
+	queue := []*ssa.BasicBlock{start}
+	checked := map[*ssa.BasicBlock]struct{}{}
+
+	for len(queue) > 0 {
+		// pop a block off of the queue
+		block := queue[len(queue)-1]
+		queue = queue[:len(queue)-1]
+
+		// Search through predecessors.
+		// Searching backwards means that this is pretty fast when the block is close to the start of the function.
+		// Defers are often placed near the start of the function.
+		for _, pred := range block.Preds {
+			if pred == start {
+				// cycle found
+				return true
+			}
+
+			if _, ok := checked[pred]; ok {
+				// block already checked
+				continue
+			}
+
+			// add to queue and checked map
+			queue = append(queue, pred)
+			checked[pred] = struct{}{}
+		}
+	}
+
+	return false
+}
+
 // emitDefer emits a single defer instruction, to be run when this function
 // returns.
 func (c *Compiler) emitDefer(frame *Frame, instr *ssa.Defer) {
@@ -127,12 +162,22 @@ func (c *Compiler) emitDefer(frame *Frame, instr *ssa.Defer) {
 		deferFrame = c.builder.CreateInsertValue(deferFrame, value, i, "")
 	}
 
-	// Put this struct in an alloca.
+	// Put this struct in an allocation.
-	alloca := c.builder.CreateAlloca(deferFrameType, "defer.alloca")
+	var alloca llvm.Value
-	c.builder.CreateStore(deferFrame, alloca)
+	if !isInLoop(instr.Block()) {
+		// This can safely use a stack allocation.
+		alloca = llvmutil.CreateEntryBlockAlloca(c.builder, deferFrameType, "defer.alloca")
+	} else {
+		// This may be hit a variable number of times, so use a heap allocation.
+		size := c.targetData.TypeAllocSize(deferFrameType)
+		sizeValue := llvm.ConstInt(c.uintptrType, size, false)
+		allocCall := c.createRuntimeCall("alloc", []llvm.Value{sizeValue}, "defer.alloc.call")
+		alloca = c.builder.CreateBitCast(allocCall, llvm.PointerType(deferFrameType, 0), "defer.alloc")
+	}
 	if c.NeedsStackObjects() {
 		c.trackPointer(alloca)
 	}
+	c.builder.CreateStore(deferFrame, alloca)
 
 	// Push it on top of the linked list by replacing deferPtr.
 	allocaCast := c.builder.CreateBitCast(alloca, next.Type(), "defer.alloca.cast")

compiler/errors.go

@@ -1,8 +1,12 @@
 package compiler
 
 import (
+	"go/scanner"
 	"go/token"
 	"go/types"
+	"path/filepath"
+
+	"tinygo.org/x/go-llvm"
 )
 
 func (c *Compiler) makeError(pos token.Pos, msg string) types.Error {
@@ -16,3 +20,42 @@ func (c *Compiler) makeError(pos token.Pos, msg string) types.Error {
 func (c *Compiler) addError(pos token.Pos, msg string) {
 	c.diagnostics = append(c.diagnostics, c.makeError(pos, msg))
 }
+
+// errorAt returns an error value at the location of the instruction.
+// The location information may not be complete as it depends on debug
+// information in the IR.
+func errorAt(inst llvm.Value, msg string) scanner.Error {
+	return scanner.Error{
+		Pos: getPosition(inst),
+		Msg: msg,
+	}
+}
+
+// getPosition returns the position information for the given value, as far as
+// it is available.
+func getPosition(val llvm.Value) token.Position {
+	if !val.IsAInstruction().IsNil() {
+		loc := val.InstructionDebugLoc()
+		if loc.IsNil() {
+			return token.Position{}
+		}
+		file := loc.LocationScope().ScopeFile()
+		return token.Position{
+			Filename: filepath.Join(file.FileDirectory(), file.FileFilename()),
+			Line:     int(loc.LocationLine()),
+			Column:   int(loc.LocationColumn()),
+		}
+	} else if !val.IsAFunction().IsNil() {
+		loc := val.Subprogram()
+		if loc.IsNil() {
+			return token.Position{}
+		}
+		file := loc.ScopeFile()
+		return token.Position{
+			Filename: filepath.Join(file.FileDirectory(), file.FileFilename()),
+			Line:     int(loc.SubprogramLine()),
+		}
+	} else {
+		return token.Position{}
+	}
+}

compiler/goroutine-lowering.go

@@ -104,7 +104,6 @@ package compiler
 // scheduler, which runs in the background scheduling all coroutines.
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 
@@ -283,7 +282,7 @@ func (c *Compiler) markAsyncFunctions() (needsScheduler bool, err error) {
 			if use.IsConstant() && use.Opcode() == llvm.PtrToInt {
 				for _, call := range getUses(use) {
 					if call.IsACallInst().IsNil() || call.CalledValue().Name() != "runtime.makeGoroutine" {
-						return false, errors.New("async function " + f.Name() + " incorrectly used in ptrtoint, expected runtime.makeGoroutine")
+						return false, errorAt(call, "async function incorrectly used in ptrtoint, expected runtime.makeGoroutine")
 					}
 				}
 				// This is a go statement. Do not mark the parent as async, as
@@ -303,12 +302,19 @@ func (c *Compiler) markAsyncFunctions() (needsScheduler bool, err error) {
 				// Not a call instruction. Maybe a store to a global? In any
 				// case, this requires support for async calls across function
 				// pointers which is not yet supported.
-				return false, errors.New("async function " + f.Name() + " used as function pointer")
+				at := use
+				if use.IsAInstruction().IsNil() {
+					// The use might not be an instruction (for example, in the
+					// case of a const bitcast). Fall back to reporting the
+					// location of the function instead.
+					at = f
+				}
+				return false, errorAt(at, "async function "+f.Name()+" used as function pointer")
 			}
 			parent := use.InstructionParent().Parent()
 			for i := 0; i < use.OperandsCount()-1; i++ {
 				if use.Operand(i) == f {
-					return false, errors.New("async function " + f.Name() + " used as function pointer in " + parent.Name())
+					return false, errorAt(use, "async function "+f.Name()+" used as function pointer")
 				}
 			}
 			worklist = append(worklist, parent)
@@ -805,7 +811,7 @@ func (c *Compiler) markAsyncFunctions() (needsScheduler bool, err error) {
 				llvm.ConstNull(c.ctx.TokenType()),
 				llvm.ConstInt(c.ctx.Int1Type(), 0, false),
 			}, "")
-			wakeup := c.splitBasicBlock(inst, llvm.NextBasicBlock(c.builder.GetInsertBlock()), "task.wakeup")
+			wakeup := llvmutil.SplitBasicBlock(c.builder, inst, llvm.NextBasicBlock(c.builder.GetInsertBlock()), "task.wakeup")
 			c.builder.SetInsertPointBefore(inst)
 			sw := c.builder.CreateSwitch(continuePoint, frame.suspendBlock, 2)
 			sw.AddCase(llvm.ConstInt(c.ctx.Int8Type(), 0, false), wakeup)
@@ -906,12 +912,12 @@ func (c *Compiler) lowerMakeGoroutineCalls(sched bool) error {
 		origFunc := ptrtointIn.Operand(0)
 		uses := getUses(goroutine)
 		if len(uses) != 1 || uses[0].IsAIntToPtrInst().IsNil() {
-			return errors.New("expected exactly 1 inttoptr use of runtime.makeGoroutine")
+			return errorAt(makeGoroutine, "expected exactly 1 inttoptr use of runtime.makeGoroutine")
 		}
 		inttoptrOut := uses[0]
 		uses = getUses(inttoptrOut)
 		if len(uses) != 1 || uses[0].IsACallInst().IsNil() {
-			return errors.New("expected exactly 1 call use of runtime.makeGoroutine bitcast")
+			return errorAt(inttoptrOut, "expected exactly 1 call use of runtime.makeGoroutine bitcast")
 		}
 		realCall := uses[0]
 

compiler/interface.go

@@ -279,14 +279,14 @@ func (c *Compiler) getInterfaceMethodSet(typ *types.Named) llvm.Value {
 		return llvm.ConstGEP(global, []llvm.Value{zero, zero})
 	}
 
-	// Every method is a *i16 reference indicating the signature of this method.
+	// Every method is a *i8 reference indicating the signature of this method.
 	methods := make([]llvm.Value, typ.Underlying().(*types.Interface).NumMethods())
 	for i := range methods {
 		method := typ.Underlying().(*types.Interface).Method(i)
 		methods[i] = c.getMethodSignature(method)
 	}
 
-	value := llvm.ConstArray(methods[0].Type(), methods)
+	value := llvm.ConstArray(c.i8ptrType, methods)
 	global = llvm.AddGlobal(c.mod, value.Type(), typ.String()+"$interface")
 	global.SetInitializer(value)
 	global.SetGlobalConstant(true)
@@ -295,7 +295,7 @@ func (c *Compiler) getInterfaceMethodSet(typ *types.Named) llvm.Value {
 }
 
 // getMethodSignature returns a global variable which is a reference to an
-// external *i16 indicating the indicating the signature of this method. It is
+// external *i8 indicating the indicating the signature of this method. It is
 // used during the interface lowering pass.
 func (c *Compiler) getMethodSignature(method *types.Func) llvm.Value {
 	signature := ir.MethodSignature(method)

compiler/interrupt.go

@@ -0,0 +1,91 @@
+package compiler
+
+import (
+	"strconv"
+	"strings"
+
+	"golang.org/x/tools/go/ssa"
+	"tinygo.org/x/go-llvm"
+)
+
+// emitInterruptGlobal creates a new runtime/interrupt.Interrupt struct that
+// will be lowered to a real interrupt during interrupt lowering.
+//
+// This two-stage approach allows unused interrupts to be optimized away if
+// necessary.
+func (c *Compiler) emitInterruptGlobal(frame *Frame, instr *ssa.CallCommon) (llvm.Value, error) {
+	// Get the interrupt number, which must be a compile-time constant.
+	id, ok := instr.Args[0].(*ssa.Const)
+	if !ok {
+		return llvm.Value{}, c.makeError(instr.Pos(), "interrupt ID is not a constant")
+	}
+
+	// Get the func value, which also must be a compile time constant.
+	// Note that bound functions are allowed if the function has a pointer
+	// receiver and is a global. This is rather strict but still allows for
+	// idiomatic Go code.
+	funcValue := c.getValue(frame, instr.Args[1])
+	if funcValue.IsAConstant().IsNil() {
+		// Try to determine the cause of the non-constantness for a nice error
+		// message.
+		switch instr.Args[1].(type) {
+		case *ssa.MakeClosure:
+			// This may also be a bound method.
+			return llvm.Value{}, c.makeError(instr.Pos(), "closures are not supported in interrupt.New")
+		}
+		// Fall back to a generic error.
+		return llvm.Value{}, c.makeError(instr.Pos(), "interrupt function must be constant")
+	}
+
+	// Create a new global of type runtime/interrupt.handle. Globals of this
+	// type are lowered in the interrupt lowering pass.
+	globalType := c.ir.Program.ImportedPackage("runtime/interrupt").Type("handle").Type()
+	globalLLVMType := c.getLLVMType(globalType)
+	globalName := "runtime/interrupt.$interrupt" + strconv.FormatInt(id.Int64(), 10)
+	if global := c.mod.NamedGlobal(globalName); !global.IsNil() {
+		return llvm.Value{}, c.makeError(instr.Pos(), "interrupt redeclared in this program")
+	}
+	global := llvm.AddGlobal(c.mod, globalLLVMType, globalName)
+	global.SetLinkage(llvm.PrivateLinkage)
+	global.SetGlobalConstant(true)
+	initializer := llvm.ConstNull(globalLLVMType)
+	initializer = llvm.ConstInsertValue(initializer, funcValue, []uint32{0})
+	initializer = llvm.ConstInsertValue(initializer, llvm.ConstInt(c.intType, uint64(id.Int64()), true), []uint32{1, 0})
+	global.SetInitializer(initializer)
+
+	// Add debug info to the interrupt global.
+	if c.Debug() {
+		pos := c.ir.Program.Fset.Position(instr.Pos())
+		diglobal := c.dibuilder.CreateGlobalVariableExpression(c.difiles[pos.Filename], llvm.DIGlobalVariableExpression{
+			Name:        "interrupt" + strconv.FormatInt(id.Int64(), 10),
+			LinkageName: globalName,
+			File:        c.getDIFile(pos.Filename),
+			Line:        pos.Line,
+			Type:        c.getDIType(globalType),
+			Expr:        c.dibuilder.CreateExpression(nil),
+			LocalToUnit: false,
+		})
+		global.AddMetadata(0, diglobal)
+	}
+
+	// Create the runtime/interrupt.Interrupt type. It is a struct with a single
+	// member of type int.
+	num := llvm.ConstPtrToInt(global, c.intType)
+	interrupt := llvm.ConstNamedStruct(c.mod.GetTypeByName("runtime/interrupt.Interrupt"), []llvm.Value{num})
+
+	// Add dummy "use" call for AVR, because interrupts may be used even though
+	// they are never referenced again. This is unlike Cortex-M or the RISC-V
+	// PLIC where each interrupt must be enabled using the interrupt number, and
+	// thus keeps the Interrupt object alive.
+	// This call is removed during interrupt lowering.
+	if strings.HasPrefix(c.Triple(), "avr") {
+		useFn := c.mod.NamedFunction("runtime/interrupt.use")
+		if useFn.IsNil() {
+			useFnType := llvm.FunctionType(c.ctx.VoidType(), []llvm.Type{interrupt.Type()}, false)
+			useFn = llvm.AddFunction(c.mod, "runtime/interrupt.use", useFnType)
+		}
+		c.builder.CreateCall(useFn, []llvm.Value{interrupt}, "")
+	}
+
+	return interrupt, nil
+}

compiler/llvm.go

@@ -52,78 +52,6 @@ func (c *Compiler) emitPointerUnpack(ptr llvm.Value, valueTypes []llvm.Type) []l
 	return llvmutil.EmitPointerUnpack(c.builder, c.mod, ptr, valueTypes)
 }
 
-// splitBasicBlock splits a LLVM basic block into two parts. All instructions
-// after afterInst are moved into a new basic block (created right after the
-// current one) with the given name.
-func (c *Compiler) splitBasicBlock(afterInst llvm.Value, insertAfter llvm.BasicBlock, name string) llvm.BasicBlock {
-	oldBlock := afterInst.InstructionParent()
-	newBlock := c.ctx.InsertBasicBlock(insertAfter, name)
-	var nextInstructions []llvm.Value // values to move
-
-	// Collect to-be-moved instructions.
-	inst := afterInst
-	for {
-		inst = llvm.NextInstruction(inst)
-		if inst.IsNil() {
-			break
-		}
-		nextInstructions = append(nextInstructions, inst)
-	}
-
-	// Move instructions.
-	c.builder.SetInsertPointAtEnd(newBlock)
-	for _, inst := range nextInstructions {
-		inst.RemoveFromParentAsInstruction()
-		c.builder.Insert(inst)
-	}
-
-	// Find PHI nodes to update.
-	var phiNodes []llvm.Value // PHI nodes to update
-	for bb := insertAfter.Parent().FirstBasicBlock(); !bb.IsNil(); bb = llvm.NextBasicBlock(bb) {
-		for inst := bb.FirstInstruction(); !inst.IsNil(); inst = llvm.NextInstruction(inst) {
-			if inst.IsAPHINode().IsNil() {
-				continue
-			}
-			needsUpdate := false
-			incomingCount := inst.IncomingCount()
-			for i := 0; i < incomingCount; i++ {
-				if inst.IncomingBlock(i) == oldBlock {
-					needsUpdate = true
-					break
-				}
-			}
-			if !needsUpdate {
-				// PHI node has no incoming edge from the old block.
-				continue
-			}
-			phiNodes = append(phiNodes, inst)
-		}
-	}
-
-	// Update PHI nodes.
-	for _, phi := range phiNodes {
-		c.builder.SetInsertPointBefore(phi)
-		newPhi := c.builder.CreatePHI(phi.Type(), "")
-		incomingCount := phi.IncomingCount()
-		incomingVals := make([]llvm.Value, incomingCount)
-		incomingBlocks := make([]llvm.BasicBlock, incomingCount)
-		for i := 0; i < incomingCount; i++ {
-			value := phi.IncomingValue(i)
-			block := phi.IncomingBlock(i)
-			if block == oldBlock {
-				block = newBlock
-			}
-			incomingVals[i] = value
-			incomingBlocks[i] = block
-		}
-		newPhi.AddIncoming(incomingVals, incomingBlocks)
-		phi.ReplaceAllUsesWith(newPhi)
-		phi.EraseFromParentAsInstruction()
-	}
-
-	return newBlock
-}
-
 // makeGlobalArray creates a new LLVM global with the given name and integers as
 // contents, and returns the global.
 // Note that it is left with the default linkage etc., you should set

compiler/llvmutil/llvm.go

@@ -94,3 +94,75 @@ func getLifetimeEndFunc(mod llvm.Module) llvm.Value {
 	}
 	return fn
 }
+
+// SplitBasicBlock splits a LLVM basic block into two parts. All instructions
+// after afterInst are moved into a new basic block (created right after the
+// current one) with the given name.
+func SplitBasicBlock(builder llvm.Builder, afterInst llvm.Value, insertAfter llvm.BasicBlock, name string) llvm.BasicBlock {
+	oldBlock := afterInst.InstructionParent()
+	newBlock := afterInst.Type().Context().InsertBasicBlock(insertAfter, name)
+	var nextInstructions []llvm.Value // values to move
+
+	// Collect to-be-moved instructions.
+	inst := afterInst
+	for {
+		inst = llvm.NextInstruction(inst)
+		if inst.IsNil() {
+			break
+		}
+		nextInstructions = append(nextInstructions, inst)
+	}
+
+	// Move instructions.
+	builder.SetInsertPointAtEnd(newBlock)
+	for _, inst := range nextInstructions {
+		inst.RemoveFromParentAsInstruction()
+		builder.Insert(inst)
+	}
+
+	// Find PHI nodes to update.
+	var phiNodes []llvm.Value // PHI nodes to update
+	for bb := insertAfter.Parent().FirstBasicBlock(); !bb.IsNil(); bb = llvm.NextBasicBlock(bb) {
+		for inst := bb.FirstInstruction(); !inst.IsNil(); inst = llvm.NextInstruction(inst) {
+			if inst.IsAPHINode().IsNil() {
+				continue
+			}
+			needsUpdate := false
+			incomingCount := inst.IncomingCount()
+			for i := 0; i < incomingCount; i++ {
+				if inst.IncomingBlock(i) == oldBlock {
+					needsUpdate = true
+					break
+				}
+			}
+			if !needsUpdate {
+				// PHI node has no incoming edge from the old block.
+				continue
+			}
+			phiNodes = append(phiNodes, inst)
+		}
+	}
+
+	// Update PHI nodes.
+	for _, phi := range phiNodes {
+		builder.SetInsertPointBefore(phi)
+		newPhi := builder.CreatePHI(phi.Type(), "")
+		incomingCount := phi.IncomingCount()
+		incomingVals := make([]llvm.Value, incomingCount)
+		incomingBlocks := make([]llvm.BasicBlock, incomingCount)
+		for i := 0; i < incomingCount; i++ {
+			value := phi.IncomingValue(i)
+			block := phi.IncomingBlock(i)
+			if block == oldBlock {
+				block = newBlock
+			}
+			incomingVals[i] = value
+			incomingBlocks[i] = block
+		}
+		newPhi.AddIncoming(incomingVals, incomingBlocks)
+		phi.ReplaceAllUsesWith(newPhi)
+		phi.EraseFromParentAsInstruction()
+	}
+
+	return newBlock
+}

compiler/optimizer.go

@@ -9,7 +9,7 @@ import (
 
 // Run the LLVM optimizer over the module.
 // The inliner can be disabled (if necessary) by passing 0 to the inlinerThreshold.
-func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) error {
+func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) []error {
 	builder := llvm.NewPassManagerBuilder()
 	defer builder.Dispose()
 	builder.SetOptLevel(optLevel)
@@ -25,9 +25,9 @@ func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) erro
 
 	// run a check of all of our code
 	if c.VerifyIR() {
-		err := c.checkModule()
+		errs := c.checkModule()
-		if err != nil {
+		if errs != nil {
-			return err
+			return errs
 		}
 	}
 
@@ -45,6 +45,7 @@ func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) erro
 		// Run some preparatory passes for the Go optimizer.
 		goPasses := llvm.NewPassManager()
 		defer goPasses.Dispose()
+		goPasses.AddGlobalDCEPass()
 		goPasses.AddGlobalOptimizerPass()
 		goPasses.AddConstantPropagationPass()
 		goPasses.AddAggressiveDCEPass()
@@ -56,7 +57,15 @@ func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) erro
 		transform.OptimizeStringToBytes(c.mod)
 		transform.OptimizeAllocs(c.mod)
 		transform.LowerInterfaces(c.mod)
-		c.LowerFuncValues()
+
+		errs := transform.LowerInterruptRegistrations(c.mod)
+		if len(errs) > 0 {
+			return errs
+		}
+
+		if c.funcImplementation() == funcValueSwitch {
+			transform.LowerFuncValues(c.mod)
+		}
 
 		// After interfaces are lowered, there are many more opportunities for
 		// interprocedural optimizations. To get them to work, function
@@ -85,24 +94,30 @@ func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) erro
 
 		err := c.LowerGoroutines()
 		if err != nil {
-			return err
+			return []error{err}
 		}
 	} else {
 		// Must be run at any optimization level.
 		transform.LowerInterfaces(c.mod)
-		c.LowerFuncValues()
+		if c.funcImplementation() == funcValueSwitch {
+			transform.LowerFuncValues(c.mod)
+		}
 		err := c.LowerGoroutines()
 		if err != nil {
-			return err
+			return []error{err}
+		}
+		errs := transform.LowerInterruptRegistrations(c.mod)
+		if len(errs) > 0 {
+			return errs
 		}
 	}
 	if c.VerifyIR() {
-		if err := c.checkModule(); err != nil {
+		if errs := c.checkModule(); errs != nil {
-			return err
+			return errs
 		}
 	}
 	if err := c.Verify(); err != nil {
-		return errors.New("optimizations caused a verification failure")
+		return []error{errors.New("optimizations caused a verification failure")}
 	}
 
 	if sizeLevel >= 2 {
@@ -141,7 +156,7 @@ func (c *Compiler) Optimize(optLevel, sizeLevel int, inlinerThreshold uint) erro
 	hasGCPass = transform.MakeGCStackSlots(c.mod) || hasGCPass
 	if hasGCPass {
 		if err := c.Verify(); err != nil {
-			return errors.New("GC pass caused a verification failure")
+			return []error{errors.New("GC pass caused a verification failure")}
 		}
 	}
 

compiler/sizes.go

@@ -110,6 +110,9 @@ func (s *StdSizes) Sizeof(T types.Type) int64 {
 		if k == types.UnsafePointer {
 			return s.PtrSize
 		}
+		if k == types.Invalid {
+			return 0 // only relevant when there is a type error somewhere
+		}
 		panic("unknown basic type: " + t.String())
 	case *types.Array:
 		n := t.Len()

compiler/symbol.go

@@ -60,16 +60,46 @@ func (c *Compiler) getGlobal(g *ssa.Global) llvm.Value {
 	info := c.getGlobalInfo(g)
 	llvmGlobal := c.mod.NamedGlobal(info.linkName)
 	if llvmGlobal.IsNil() {
-		llvmType := c.getLLVMType(g.Type().(*types.Pointer).Elem())
+		typ := g.Type().(*types.Pointer).Elem()
+		llvmType := c.getLLVMType(typ)
 		llvmGlobal = llvm.AddGlobal(c.mod, llvmType, info.linkName)
 		if !info.extern {
 			llvmGlobal.SetInitializer(llvm.ConstNull(llvmType))
 			llvmGlobal.SetLinkage(llvm.InternalLinkage)
 		}
+
+		// Set alignment from the //go:align comment.
+		var alignInBits uint32
+		if info.align < 0 || info.align&(info.align-1) != 0 {
+			// Check for power-of-two (or 0).
+			// See: https://stackoverflow.com/a/108360
+			c.addError(g.Pos(), "global variable alignment must be a positive power of two")
+		} else {
+			// Set the alignment only when it is a power of two.
+			alignInBits = uint32(info.align) ^ uint32(info.align-1)
 			if info.align > c.targetData.ABITypeAlignment(llvmType) {
 				llvmGlobal.SetAlignment(info.align)
 			}
 		}
+
+		if c.Debug() {
+			// Add debug info.
+			// TODO: this should be done for every global in the program, not just
+			// the ones that are referenced from some code.
+			pos := c.ir.Program.Fset.Position(g.Pos())
+			diglobal := c.dibuilder.CreateGlobalVariableExpression(c.difiles[pos.Filename], llvm.DIGlobalVariableExpression{
+				Name:        g.RelString(nil),
+				LinkageName: info.linkName,
+				File:        c.getDIFile(pos.Filename),
+				Line:        pos.Line,
+				Type:        c.getDIType(typ),
+				LocalToUnit: false,
+				Expr:        c.dibuilder.CreateExpression(nil),
+				AlignInBits: alignInBits,
+			})
+			llvmGlobal.AddMetadata(0, diglobal)
+		}
+	}
 	return llvmGlobal
 }
 

compiler/syscall.go

@@ -152,7 +152,7 @@ func (c *Compiler) emitSyscall(frame *Frame, call *ssa.CallCommon) (llvm.Value,
 		return llvm.Value{}, c.makeError(call.Pos(), "unknown GOOS/GOARCH for syscall: "+c.GOOS()+"/"+c.GOARCH())
 	}
 	switch c.GOOS() {
-	case "linux":
+	case "linux", "freebsd":
 		// Return values: r0, r1 uintptr, err Errno
 		// Pseudocode:
 		//     var err uintptr

go.mod

@@ -10,5 +10,5 @@ require (
 	go.bug.st/serial.v1 v0.0.0-20180827123349-5f7892a7bb45
 	golang.org/x/sys v0.0.0-20191010194322-b09406accb47 // indirect
 	golang.org/x/tools v0.0.0-20190227180812-8dcc6e70cdef
-	tinygo.org/x/go-llvm v0.0.0-20191124211856-b2db3df3f257
+	tinygo.org/x/go-llvm v0.0.0-20200104190746-1ff21df33566
 )

go.sum

@@ -30,3 +30,7 @@ tinygo.org/x/go-llvm v0.0.0-20191113125529-bad6d01809e8 h1:9Bfvso+tTVQg16UzOA614
 tinygo.org/x/go-llvm v0.0.0-20191113125529-bad6d01809e8/go.mod h1:fv1F0BSNpxMfCL0zF3M4OPFbgYHnhtB6ST0HvUtu/LE=
 tinygo.org/x/go-llvm v0.0.0-20191124211856-b2db3df3f257 h1:o8VDylrMN7gWemBMu8rEyuogKPhcLTdx5KrUAp9macc=
 tinygo.org/x/go-llvm v0.0.0-20191124211856-b2db3df3f257/go.mod h1:fv1F0BSNpxMfCL0zF3M4OPFbgYHnhtB6ST0HvUtu/LE=
+tinygo.org/x/go-llvm v0.0.0-20191215173731-ad71f3d24aae h1:s8J5EyxCkHxXB08UI3gk9W9IS/ekizRvSX+PfZxnAB0=
+tinygo.org/x/go-llvm v0.0.0-20191215173731-ad71f3d24aae/go.mod h1:fv1F0BSNpxMfCL0zF3M4OPFbgYHnhtB6ST0HvUtu/LE=
+tinygo.org/x/go-llvm v0.0.0-20200104190746-1ff21df33566 h1:a4y30bTf7U0zDA75v2PTL+XQ2OzJetj19gK8XwQpUNY=
+tinygo.org/x/go-llvm v0.0.0-20200104190746-1ff21df33566/go.mod h1:fv1F0BSNpxMfCL0zF3M4OPFbgYHnhtB6ST0HvUtu/LE=

interp/frame.go

@@ -278,24 +278,49 @@ func (fr *frame) evalBasicBlock(bb, incoming llvm.BasicBlock, indent string) (re
 				}
 			case callee.Name() == "runtime.hashmapStringSet":
 				// set a string key in the map
-				m, ok := fr.getLocal(inst.Operand(0)).(*MapValue)
-				if !ok {
-					return nil, nil, fr.errorAt(inst, "could not update map with string key")
-				}
-				// "key" is a Go string value, which in the TinyGo calling convention is split up
-				// into separate pointer and length parameters.
 				keyBuf := fr.getLocal(inst.Operand(1)).(*LocalValue)
 				keyLen := fr.getLocal(inst.Operand(2)).(*LocalValue)
 				valPtr := fr.getLocal(inst.Operand(3)).(*LocalValue)
+				m, ok := fr.getLocal(inst.Operand(0)).(*MapValue)
+				if !ok || !keyBuf.IsConstant() || !keyLen.IsConstant() || !valPtr.IsConstant() {
+					// The mapassign operation could not be done at compile
+					// time. Do it at runtime instead.
+					m := fr.getLocal(inst.Operand(0)).Value()
+					fr.markDirty(m)
+					llvmParams := []llvm.Value{
+						m,                                    // *runtime.hashmap
+						fr.getLocal(inst.Operand(1)).Value(), // key.ptr
+						fr.getLocal(inst.Operand(2)).Value(), // key.len
+						fr.getLocal(inst.Operand(3)).Value(), // value (unsafe.Pointer)
+						fr.getLocal(inst.Operand(4)).Value(), // context
+						fr.getLocal(inst.Operand(5)).Value(), // parentHandle
+					}
+					fr.builder.CreateCall(callee, llvmParams, "")
+					continue
+				}
+				// "key" is a Go string value, which in the TinyGo calling convention is split up
+				// into separate pointer and length parameters.
 				m.PutString(keyBuf, keyLen, valPtr)
 			case callee.Name() == "runtime.hashmapBinarySet":
 				// set a binary (int etc.) key in the map
-				m, ok := fr.getLocal(inst.Operand(0)).(*MapValue)
-				if !ok {
-					return nil, nil, fr.errorAt(inst, "could not update map")
-				}
 				keyBuf := fr.getLocal(inst.Operand(1)).(*LocalValue)
 				valPtr := fr.getLocal(inst.Operand(2)).(*LocalValue)
+				m, ok := fr.getLocal(inst.Operand(0)).(*MapValue)
+				if !ok || !keyBuf.IsConstant() || !valPtr.IsConstant() {
+					// The mapassign operation could not be done at compile
+					// time. Do it at runtime instead.
+					m := fr.getLocal(inst.Operand(0)).Value()
+					fr.markDirty(m)
+					llvmParams := []llvm.Value{
+						m,                                    // *runtime.hashmap
+						fr.getLocal(inst.Operand(1)).Value(), // key
+						fr.getLocal(inst.Operand(2)).Value(), // value
+						fr.getLocal(inst.Operand(3)).Value(), // context
+						fr.getLocal(inst.Operand(4)).Value(), // parentHandle
+					}
+					fr.builder.CreateCall(callee, llvmParams, "")
+					continue
+				}
 				m.PutBinary(keyBuf, valPtr)
 			case callee.Name() == "runtime.stringConcat":
 				// adding two strings together
@@ -433,6 +458,8 @@ func (fr *frame) evalBasicBlock(bb, incoming llvm.BasicBlock, indent string) (re
 				fr.locals[inst] = &LocalValue{fr.Eval, llvm.ConstInt(fr.Mod.Context().Int64Type(), 0, false)}
 			case callee.Name() == "llvm.dbg.value":
 				// do nothing
+			case strings.HasPrefix(callee.Name(), "llvm.lifetime."):
+				// do nothing
 			case callee.Name() == "runtime.trackPointer":
 				// do nothing
 			case strings.HasPrefix(callee.Name(), "runtime.print") || callee.Name() == "runtime._panic":

interp/interp_test.go

@@ -14,6 +14,7 @@ func TestInterp(t *testing.T) {
 		"basic",
 		"slice-copy",
 		"consteval",
+		"map",
 	} {
 		name := name // make tc local to this closure
 		t.Run(name, func(t *testing.T) {

interp/scan.go

@@ -1,6 +1,8 @@
 package interp
 
 import (
+	"strings"
+
 	"tinygo.org/x/go-llvm"
 )
 
@@ -39,22 +41,25 @@ type sideEffectResult struct {
 // returns whether this function has side effects and if it does, which globals
 // it mentions anywhere in this function or any called functions.
 func (e *evalPackage) hasSideEffects(fn llvm.Value) (*sideEffectResult, error) {
-	switch fn.Name() {
+	name := fn.Name()
-	case "runtime.alloc":
+	switch {
+	case name == "runtime.alloc":
 		// Cannot be scanned but can be interpreted.
 		return &sideEffectResult{severity: sideEffectNone}, nil
-	case "runtime.nanotime":
+	case name == "runtime.nanotime":
 		// Fixed value at compile time.
 		return &sideEffectResult{severity: sideEffectNone}, nil
-	case "runtime._panic":
+	case name == "runtime._panic":
 		return &sideEffectResult{severity: sideEffectLimited}, nil
-	case "runtime.interfaceImplements":
+	case name == "runtime.interfaceImplements":
 		return &sideEffectResult{severity: sideEffectNone}, nil
-	case "runtime.sliceCopy":
+	case name == "runtime.sliceCopy":
 		return &sideEffectResult{severity: sideEffectNone}, nil
-	case "runtime.trackPointer":
+	case name == "runtime.trackPointer":
 		return &sideEffectResult{severity: sideEffectNone}, nil
-	case "llvm.dbg.value":
+	case name == "llvm.dbg.value":
+		return &sideEffectResult{severity: sideEffectNone}, nil
+	case strings.HasPrefix(name, "llvm.lifetime."):
 		return &sideEffectResult{severity: sideEffectNone}, nil
 	}
 	if fn.IsDeclaration() {

interp/testdata/map.ll

@@ -0,0 +1,76 @@
+target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv6m-none-eabi"
+
+%runtime._string = type { i8*, i32 }
+%runtime.hashmap = type { %runtime.hashmap*, i8*, i32, i8, i8, i8 }
+
+@main.m = global %runtime.hashmap* null
+@main.binaryMap = global %runtime.hashmap* null
+@main.stringMap = global %runtime.hashmap* null
+@main.init.string = internal unnamed_addr constant [7 x i8] c"CONNECT"
+
+declare %runtime.hashmap* @runtime.hashmapMake(i8, i8, i32, i8* %context, i8* %parentHandle)
+declare void @runtime.hashmapBinarySet(%runtime.hashmap*, i8*, i8*, i8* %context, i8* %parentHandle)
+declare void @runtime.hashmapStringSet(%runtime.hashmap*, i8*, i32, i8*, i8* %context, i8* %parentHandle)
+declare void @llvm.lifetime.end.p0i8(i64, i8*)
+declare void @llvm.lifetime.start.p0i8(i64, i8*)
+
+define void @runtime.initAll() unnamed_addr {
+entry:
+  call void @main.init(i8* undef, i8* null)
+  ret void
+}
+
+define internal void @main.init(i8* %context, i8* %parentHandle) unnamed_addr {
+entry:
+; Test that hashmap optimizations generally work (even with lifetimes).
+  %hashmap.key = alloca i8
+  %hashmap.value = alloca %runtime._string
+  %0 = call %runtime.hashmap* @runtime.hashmapMake(i8 1, i8 8, i32 1, i8* undef, i8* null)
+  %hashmap.value.bitcast = bitcast %runtime._string* %hashmap.value to i8*
+  call void @llvm.lifetime.start.p0i8(i64 8, i8* %hashmap.value.bitcast)
+  store %runtime._string { i8* getelementptr inbounds ([7 x i8], [7 x i8]* @main.init.string, i32 0, i32 0), i32 7 }, %runtime._string* %hashmap.value
+  call void @llvm.lifetime.start.p0i8(i64 1, i8* %hashmap.key)
+  store i8 1, i8* %hashmap.key
+  call void @runtime.hashmapBinarySet(%runtime.hashmap* %0, i8* %hashmap.key, i8* %hashmap.value.bitcast, i8* undef, i8* null)
+  call void @llvm.lifetime.end.p0i8(i64 1, i8* %hashmap.key)
+  call void @llvm.lifetime.end.p0i8(i64 8, i8* %hashmap.value.bitcast)
+  store %runtime.hashmap* %0, %runtime.hashmap** @main.m
+
+  ; Other tests, that can be done in a separate function.
+  call void @main.testNonConstantBinarySet()
+  call void @main.testNonConstantStringSet()
+  ret void
+}
+
+; Test that a map loaded from a global can still be used for mapassign
+; operations (with binary keys).
+define internal void @main.testNonConstantBinarySet() {
+  %hashmap.key = alloca i8
+  %hashmap.value = alloca i8
+  ; Create hashmap from global. This breaks the normal hashmapBinarySet
+  ; optimization, to test the fallback.
+  %map.new = call %runtime.hashmap* @runtime.hashmapMake(i8 1, i8 1, i32 1, i8* undef, i8* null)
+  store %runtime.hashmap* %map.new, %runtime.hashmap** @main.binaryMap
+  %map = load %runtime.hashmap*, %runtime.hashmap** @main.binaryMap
+  ; Do the binary set to the newly loaded map.
+  store i8 1, i8* %hashmap.key
+  store i8 2, i8* %hashmap.value
+  call void @runtime.hashmapBinarySet(%runtime.hashmap* %map, i8* %hashmap.key, i8* %hashmap.value, i8* undef, i8* null)
+  ret void
+}
+
+; Test that a map loaded from a global can still be used for mapassign
+; operations (with string keys).
+define internal void @main.testNonConstantStringSet() {
+  %hashmap.value = alloca i8
+  ; Create hashmap from global. This breaks the normal hashmapStringSet
+  ; optimization, to test the fallback.
+  %map.new = call %runtime.hashmap* @runtime.hashmapMake(i8 8, i8 1, i32 1, i8* undef, i8* null)
+  store %runtime.hashmap* %map.new, %runtime.hashmap** @main.stringMap
+  %map = load %runtime.hashmap*, %runtime.hashmap** @main.stringMap
+  ; Do the string set to the newly loaded map.
+  store i8 2, i8* %hashmap.value
+  call void @runtime.hashmapStringSet(%runtime.hashmap* %map, i8* getelementptr inbounds ([7 x i8], [7 x i8]* @main.init.string, i32 0, i32 0), i32 7, i8* %hashmap.value, i8* undef, i8* null)
+  ret void
+}

interp/testdata/map.out.ll

@@ -0,0 +1,28 @@
+target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "armv6m-none-eabi"
+
+%runtime.hashmap = type { %runtime.hashmap*, i8*, i32, i8, i8, i8 }
+%runtime._string = type { i8*, i32 }
+
+@main.m = local_unnamed_addr global %runtime.hashmap* @"main$map"
+@main.binaryMap = local_unnamed_addr global %runtime.hashmap* @"main$map.4"
+@main.stringMap = local_unnamed_addr global %runtime.hashmap* @"main$map.6"
+@main.init.string = internal unnamed_addr constant [7 x i8] c"CONNECT"
+@"main$mapbucket" = internal unnamed_addr global { [8 x i8], i8*, [8 x i8], [8 x %runtime._string] } { [8 x i8] c"\04\00\00\00\00\00\00\00", i8* null, [8 x i8] c"\01\00\00\00\00\00\00\00", [8 x %runtime._string] [%runtime._string { i8* getelementptr inbounds ([7 x i8], [7 x i8]* @main.init.string, i32 0, i32 0), i32 7 }, %runtime._string zeroinitializer, %runtime._string zeroinitializer, %runtime._string zeroinitializer, %runtime._string zeroinitializer, %runtime._string zeroinitializer, %runtime._string zeroinitializer, %runtime._string zeroinitializer] }
+@"main$map" = internal unnamed_addr global %runtime.hashmap { %runtime.hashmap* null, i8* getelementptr inbounds ({ [8 x i8], i8*, [8 x i8], [8 x %runtime._string] }, { [8 x i8], i8*, [8 x i8], [8 x %runtime._string] }* @"main$mapbucket", i32 0, i32 0, i32 0), i32 1, i8 1, i8 8, i8 0 }
+@"main$alloca.2" = internal global i8 1
+@"main$alloca.3" = internal global i8 2
+@"main$map.4" = internal unnamed_addr global %runtime.hashmap { %runtime.hashmap* null, i8* null, i32 0, i8 1, i8 1, i8 0 }
+@"main$alloca.5" = internal global i8 2
+@"main$map.6" = internal unnamed_addr global %runtime.hashmap { %runtime.hashmap* null, i8* null, i32 0, i8 8, i8 1, i8 0 }
+
+declare void @runtime.hashmapBinarySet(%runtime.hashmap*, i8*, i8*, i8*, i8*) local_unnamed_addr
+
+declare void @runtime.hashmapStringSet(%runtime.hashmap*, i8*, i32, i8*, i8*, i8*) local_unnamed_addr
+
+define void @runtime.initAll() unnamed_addr {
+entry:
+  call void @runtime.hashmapBinarySet(%runtime.hashmap* @"main$map.4", i8* @"main$alloca.2", i8* @"main$alloca.3", i8* undef, i8* null)
+  call void @runtime.hashmapStringSet(%runtime.hashmap* @"main$map.6", i8* getelementptr inbounds ([7 x i8], [7 x i8]* @main.init.string, i32 0, i32 0), i32 7, i8* @"main$alloca.5", i8* undef, i8* null)
+  ret void
+}

interp/values.go

@@ -367,11 +367,13 @@ func (v *MapValue) PutBinary(keyPtr, valPtr *LocalValue) {
 		}
 	}
 
+	if !keyPtr.Underlying.IsAConstantExpr().IsNil() {
 		if keyPtr.Underlying.Opcode() == llvm.BitCast {
 			keyPtr = &LocalValue{v.Eval, keyPtr.Underlying.Operand(0)}
 		} else if keyPtr.Underlying.Opcode() == llvm.GetElementPtr {
 			keyPtr = &LocalValue{v.Eval, keyPtr.Underlying.Operand(0)}
 		}
+	}
 	key := keyPtr.Load()
 	if v.KeyType.IsNil() {
 		v.KeyType = key.Type()

ir/ir.go

@@ -29,11 +29,10 @@ type Function struct {
 	*ssa.Function
 	LLVMFn   llvm.Value
 	module   string     // go:wasm-module
-	linkName  string     // go:linkname, go:export, go:interrupt
+	linkName string     // go:linkname, go:export
 	exported bool       // go:export
 	nobounds bool       // go:nobounds
 	flag     bool       // used by dead code elimination
-	interrupt bool       // go:interrupt
 	inline   InlineType // go:inline
 }
 
@@ -243,18 +242,6 @@ func (f *Function) parsePragmas() {
 				f.inline = InlineHint
 			case "//go:noinline":
 				f.inline = InlineNone
-			case "//go:interrupt":
-				if len(parts) != 2 {
-					continue
-				}
-				name := parts[1]
-				if strings.HasSuffix(name, "_vect") {
-					// AVR vector naming
-					name = "__vector_" + name[:len(name)-5]
-				}
-				f.linkName = name
-				f.exported = true
-				f.interrupt = true
 			case "//go:linkname":
 				if len(parts) != 3 || parts[1] != f.Name() {
 					continue
@@ -288,14 +275,6 @@ func (f *Function) IsExported() bool {
 	return f.exported || f.CName() != ""
 }
 
-// Return true for functions annotated with //go:interrupt. The function name is
-// already customized in LinkName() to hook up in the interrupt vector.
-//
-// On some platforms (like AVR), interrupts need a special compiler flag.
-func (f *Function) IsInterrupt() bool {
-	return f.interrupt
-}
-
 // Return the inline directive of this function.
 func (f *Function) Inline() InlineType {
 	return f.inline

loader/loader.go

@@ -6,6 +6,7 @@ import (
 	"go/ast"
 	"go/build"
 	"go/parser"
+	"go/scanner"
 	"go/token"
 	"go/types"
 	"os"
@@ -46,7 +47,7 @@ type Package struct {
 
 // Import loads the given package relative to srcDir (for the vendor directory).
 // It only loads the current package without recursion.
-func (p *Program) Import(path, srcDir string) (*Package, error) {
+func (p *Program) Import(path, srcDir string, pos token.Position) (*Package, error) {
 	if p.Packages == nil {
 		p.Packages = make(map[string]*Package)
 	}
@@ -59,7 +60,10 @@ func (p *Program) Import(path, srcDir string) (*Package, error) {
 	}
 	buildPkg, err := ctx.Import(path, srcDir, build.ImportComment)
 	if err != nil {
-		return nil, err
+		return nil, scanner.Error{
+			Pos: pos,
+			Msg: err.Error(), // TODO: define a new error type that will wrap the inner error
+		}
 	}
 	if existingPkg, ok := p.Packages[buildPkg.ImportPath]; ok {
 		// Already imported, or at least started the import.
@@ -467,7 +471,14 @@ func (p *Package) importRecursively(includeTests bool) error {
 		if _, ok := p.Imports[to]; ok {
 			continue
 		}
-		importedPkg, err := p.Program.Import(to, p.Package.Dir)
+		// Find error location.
+		var pos token.Position
+		if len(p.Package.ImportPos[to]) > 0 {
+			pos = p.Package.ImportPos[to][0]
+		} else {
+			pos = token.Position{Filename: p.Package.ImportPath}
+		}
+		importedPkg, err := p.Program.Import(to, p.Package.Dir, pos)
 		if err != nil {
 			if err, ok := err.(*ImportCycleError); ok {
 				err.Packages = append([]string{p.ImportPath}, err.Packages...)

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"errors"
 	"flag"
 	"fmt"
@@ -144,6 +145,14 @@ func Test(pkgName string, options *compileopts.Options) error {
 
 // Flash builds and flashes the built binary to the given serial port.
 func Flash(pkgName, port string, options *compileopts.Options) error {
+	if port == "" {
+		var err error
+		port, err = getDefaultPort()
+		if err != nil {
+			return err
+		}
+	}
+
 	config, err := builder.NewConfig(options)
 	if err != nil {
 		return err
@@ -201,7 +210,18 @@ func Flash(pkgName, port string, options *compileopts.Options) error {
 			flashCmd = strings.Replace(flashCmd, "{port}", port, -1)
 
 			// Execute the command.
-			cmd := exec.Command("/bin/sh", "-c", flashCmd)
+			var cmd *exec.Cmd
+			switch runtime.GOOS {
+			case "windows":
+				command := strings.Split(flashCmd, " ")
+				if len(command) < 2 {
+					return errors.New("invalid flash command")
+				}
+				cmd = exec.Command(command[0], command[1:]...)
+			default:
+				cmd = exec.Command("/bin/sh", "-c", flashCmd)
+			}
+
 			cmd.Stdout = os.Stdout
 			cmd.Stderr = os.Stderr
 			cmd.Dir = goenv.Get("TINYGOROOT")
@@ -254,7 +274,7 @@ func Flash(pkgName, port string, options *compileopts.Options) error {
 //
 // Note: this command is expected to execute just before exiting, as it
 // modifies global state.
-func FlashGDB(pkgName, port string, ocdOutput bool, options *compileopts.Options) error {
+func FlashGDB(pkgName string, ocdOutput bool, options *compileopts.Options) error {
 	config, err := builder.NewConfig(options)
 	if err != nil {
 		return err
@@ -268,12 +288,13 @@ func FlashGDB(pkgName, port string, ocdOutput bool, options *compileopts.Options
 		gdbInterface, openocdInterface := config.Programmer()
 		switch gdbInterface {
 		case "msd", "command", "":
-			if gdbInterface == "" {
-				gdbInterface = "command"
-			}
 			if openocdInterface != "" && config.Target.OpenOCDTarget != "" {
 				gdbInterface = "openocd"
 			}
+			if len(config.Target.Emulator) != 0 {
+				// Assume QEMU as an emulator.
+				gdbInterface = "qemu"
+			}
 		}
 
 		// Run the GDB server, if necessary.
@@ -303,6 +324,26 @@ func FlashGDB(pkgName, port string, ocdOutput bool, options *compileopts.Options
 			// Make sure the daemon doesn't receive Ctrl-C that is intended for
 			// GDB (to break the currently executing program).
 			setCommandAsDaemon(daemon)
+			// Start now, and kill it on exit.
+			daemon.Start()
+			defer func() {
+				daemon.Process.Signal(os.Interrupt)
+				// Maybe we should send a .Kill() after x seconds?
+				daemon.Wait()
+			}()
+		case "qemu":
+			gdbCommands = append(gdbCommands, "target remote :1234")
+
+			// Run in an emulator.
+			args := append(config.Target.Emulator[1:], tmppath, "-s", "-S")
+			daemon := exec.Command(config.Target.Emulator[0], args...)
+			daemon.Stdout = os.Stdout
+			daemon.Stderr = os.Stderr
+
+			// Make sure the daemon doesn't receive Ctrl-C that is intended for
+			// GDB (to break the currently executing program).
+			setCommandAsDaemon(daemon)
+
 			// Start now, and kill it on exit.
 			daemon.Start()
 			defer func() {
@@ -401,9 +442,18 @@ func touchSerialPortAt1200bps(port string) error {
 
 func flashUF2UsingMSD(volume, tmppath string) error {
 	// find standard UF2 info path
-	infoPath := "/media/*/" + volume + "/INFO_UF2.TXT"
+	var infoPath string
-	if runtime.GOOS == "darwin" {
+	switch runtime.GOOS {
+	case "linux", "freebsd":
+		infoPath = "/media/*/" + volume + "/INFO_UF2.TXT"
+	case "darwin":
 		infoPath = "/Volumes/" + volume + "/INFO_UF2.TXT"
+	case "windows":
+		path, err := windowsFindUSBDrive(volume)
+		if err != nil {
+			return err
+		}
+		infoPath = path + "/INFO_UF2.TXT"
 	}
 
 	d, err := filepath.Glob(infoPath)
@@ -419,9 +469,18 @@ func flashUF2UsingMSD(volume, tmppath string) error {
 
 func flashHexUsingMSD(volume, tmppath string) error {
 	// find expected volume path
-	destPath := "/media/*/" + volume
+	var destPath string
-	if runtime.GOOS == "darwin" {
+	switch runtime.GOOS {
+	case "linux", "freebsd":
+		destPath = "/media/*/" + volume
+	case "darwin":
 		destPath = "/Volumes/" + volume
+	case "windows":
+		path, err := windowsFindUSBDrive(volume)
+		if err != nil {
+			return err
+		}
+		destPath = path + "/"
 	}
 
 	d, err := filepath.Glob(destPath)
@@ -435,6 +494,29 @@ func flashHexUsingMSD(volume, tmppath string) error {
 	return moveFile(tmppath, d[0]+"/flash.hex")
 }
 
+func windowsFindUSBDrive(volume string) (string, error) {
+	cmd := exec.Command("wmic",
+		"PATH", "Win32_LogicalDisk", "WHERE", "VolumeName = '"+volume+"'",
+		"get", "DeviceID,VolumeName,FileSystem,DriveType")
+
+	var out bytes.Buffer
+	cmd.Stdout = &out
+	err := cmd.Run()
+	if err != nil {
+		return "", err
+	}
+
+	for _, line := range strings.Split(out.String(), "\n") {
+		words := strings.Fields(line)
+		if len(words) >= 3 {
+			if words[1] == "2" && words[2] == "FAT" {
+				return words[0], nil
+			}
+		}
+	}
+	return "", errors.New("unable to locate a USB device to be flashed")
+}
+
 // parseSize converts a human-readable size (with k/m/g suffix) into a plain
 // number.
 func parseSize(s string) (int64, error) {
@@ -459,6 +541,56 @@ func parseSize(s string) (int64, error) {
 	return n, err
 }
 
+// getDefaultPort returns the default serial port depending on the operating system.
+// Currently only supports macOS and Linux.
+func getDefaultPort() (port string, err error) {
+	var portPath string
+	switch runtime.GOOS {
+	case "darwin":
+		portPath = "/dev/cu.usb*"
+	case "linux":
+		portPath = "/dev/ttyACM*"
+	case "freebsd":
+		portPath = "/dev/cuaU*"
+	case "windows":
+		cmd := exec.Command("wmic",
+			"PATH", "Win32_SerialPort", "WHERE", "Caption LIKE 'USB Serial%'", "GET", "DeviceID")
+
+		var out bytes.Buffer
+		cmd.Stdout = &out
+		err := cmd.Run()
+		if err != nil {
+			return "", err
+		}
+
+		if out.String() == "No Instance(s) Available." {
+			return "", errors.New("unable to locate a USB device to be flashed")
+		}
+
+		for _, line := range strings.Split(out.String(), "\n") {
+			words := strings.Fields(line)
+			if len(words) == 1 {
+				if strings.Contains(words[0], "COM") {
+					return words[0], nil
+				}
+			}
+		}
+		return "", errors.New("unable to locate a USB device to be flashed")
+	default:
+		return "", errors.New("unable to search for a default USB device to be flashed on this OS")
+	}
+
+	d, err := filepath.Glob(portPath)
+	if err != nil {
+		return "", err
+	}
+	if d == nil {
+		return "", errors.New("unable to locate a USB device to be flashed")
+	}
+
+	return d[0], nil
+}
+
 func usage() {
 	fmt.Fprintln(os.Stderr, "TinyGo is a Go compiler for small places.")
 	fmt.Fprintln(os.Stderr, "version:", version)
@@ -526,7 +658,7 @@ func main() {
 	printSize := flag.String("size", "", "print sizes (none, short, full)")
 	nodebug := flag.Bool("no-debug", false, "disable DWARF debug symbol generation")
 	ocdOutput := flag.Bool("ocd-output", false, "print OCD daemon output during debug")
-	port := flag.String("port", "/dev/ttyACM0", "flash port")
+	port := flag.String("port", "", "flash port")
 	programmer := flag.String("programmer", "", "which hardware programmer to use")
 	cFlags := flag.String("cflags", "", "additional cflags for compiler")
 	ldFlags := flag.String("ldflags", "", "additional ldflags for linker")
@@ -629,7 +761,7 @@ func main() {
 				usage()
 				os.Exit(1)
 			}
-			err := FlashGDB(flag.Arg(0), *port, *ocdOutput, options)
+			err := FlashGDB(flag.Arg(0), *ocdOutput, options)
 			handleCompilerError(err)
 		}
 	case "run":

main_test.go

@@ -12,7 +12,9 @@ import (
 	"path/filepath"
 	"runtime"
 	"sort"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/tinygo-org/tinygo/compileopts"
 	"github.com/tinygo-org/tinygo/loader"
@@ -50,7 +52,7 @@ func TestCompiler(t *testing.T) {
 	}
 
 	t.Run("EmulatedCortexM3", func(t *testing.T) {
-		runPlatTests("qemu", matches, t)
+		runPlatTests("cortex-m-qemu", matches, t)
 	})
 
 	if runtime.GOOS == "linux" {
@@ -67,6 +69,8 @@ func TestCompiler(t *testing.T) {
 }
 
 func runPlatTests(target string, matches []string, t *testing.T) {
+	t.Parallel()
+
 	for _, path := range matches {
 		switch {
 		case target == "wasm":
@@ -76,7 +80,7 @@ func runPlatTests(target string, matches []string, t *testing.T) {
 			}
 		case target == "":
 			// run all tests on host
-		case target == "qemu":
+		case target == "cortex-m-qemu":
 			// all tests are supported
 		default:
 			// cross-compilation of cgo is not yet supported
@@ -86,22 +90,32 @@ func runPlatTests(target string, matches []string, t *testing.T) {
 		}
 
 		t.Run(filepath.Base(path), func(t *testing.T) {
+			t.Parallel()
+
 			runTest(path, target, t)
 		})
 	}
 }
 
+// Due to some problems with LLD, we cannot run links in parallel, or in parallel with compiles.
+// Therefore, we put a lock around builds and run everything else in parallel.
+var buildLock sync.Mutex
+
+// runBuild is a thread-safe wrapper around Build.
+func runBuild(src, out string, opts *compileopts.Options) error {
+	buildLock.Lock()
+	defer buildLock.Unlock()
+
+	return Build(src, out, opts)
+}
+
 func runTest(path, target string, t *testing.T) {
 	// Get the expected output for this test.
 	txtpath := path[:len(path)-3] + ".txt"
 	if path[len(path)-1] == os.PathSeparator {
 		txtpath = path + "out.txt"
 	}
-	f, err := os.Open(txtpath)
+	expected, err := ioutil.ReadFile(txtpath)
-	if err != nil {
-		t.Fatal("could not open expected output file:", err)
-	}
-	expected, err := ioutil.ReadAll(f)
 	if err != nil {
 		t.Fatal("could not read expected output file:", err)
 	}
@@ -130,7 +144,7 @@ func runTest(path, target string, t *testing.T) {
 		WasmAbi:    "js",
 	}
 	binary := filepath.Join(tmpdir, "test")
-	err = Build("./"+path, binary, config)
+	err = runBuild("./"+path, binary, config)
 	if err != nil {
 		if errLoader, ok := err.(loader.Errors); ok {
 			for _, err := range errLoader.Errs {
@@ -144,7 +158,9 @@ func runTest(path, target string, t *testing.T) {
 	}
 
 	// Run the test.
+	runComplete := make(chan struct{})
 	var cmd *exec.Cmd
+	ranTooLong := false
 	if target == "" {
 		cmd = exec.Command(binary)
 	} else {
@@ -160,13 +176,35 @@ func runTest(path, target string, t *testing.T) {
 	}
 	stdout := &bytes.Buffer{}
 	cmd.Stdout = stdout
-	if target != "" {
 	cmd.Stderr = os.Stderr
+	err = cmd.Start()
+	if err != nil {
+		t.Fatal("failed to start:", err)
 	}
-	err = cmd.Run()
+	go func() {
+		// Terminate the process if it runs too long.
+		timer := time.NewTimer(1 * time.Second)
+		select {
+		case <-runComplete:
+			timer.Stop()
+		case <-timer.C:
+			ranTooLong = true
+			if runtime.GOOS == "windows" {
+				cmd.Process.Signal(os.Kill) // Windows doesn't support SIGINT.
+			} else {
+				cmd.Process.Signal(os.Interrupt)
+			}
+		}
+	}()
+	err = cmd.Wait()
 	if _, ok := err.(*exec.ExitError); ok && target != "" {
 		err = nil // workaround for QEMU
 	}
+	close(runComplete)
+
+	if ranTooLong {
+		stdout.WriteString("--- test ran too long, terminating...\n")
+	}
 
 	// putchar() prints CRLF, convert it to LF.
 	actual := bytes.Replace(stdout.Bytes(), []byte{'\r', '\n'}, []byte{'\n'}, -1)

src/device/riscv/start.S

@@ -3,11 +3,10 @@
 .type _start,@function
 
 _start:
-    // Workaround for missing support of the la pseudo-instruction in Clang 8:
+    // Load the stack pointer.
-    // https://reviews.llvm.org/D55325
+    la sp,      _stack_top
-    lui sp,      %hi(_stack_top)
+    // Load the globals pointer. The program will load pointers relative to this
-    addi sp, sp, %lo(_stack_top)
+    // register, so it must be set to the right value on startup.
-    // see https://gnu-mcu-eclipse.github.io/arch/riscv/programmer/#the-gp-global-pointer-register
+    // See: https://gnu-mcu-eclipse.github.io/arch/riscv/programmer/#the-gp-global-pointer-register
-    lui gp,      %hi(__global_pointer$)
+    la gp,      __global_pointer$
-    addi gp, gp, %lo(__global_pointer$)
     call main

src/device/stm32/stm32f103xx-bitfields.go

@@ -1,5 +1,5 @@
 // Hand created file. DO NOT DELETE.
-// STM32F103XX bitfield definitions that are not auto-generated by gen-device-svd.py
+// STM32F103XX bitfield definitions that are not auto-generated by gen-device-svd.go
 
 // +build stm32,stm32f103xx
 

src/examples/systick/systick.go

@@ -9,7 +9,7 @@ func main() {
 	machine.LED.Configure(machine.PinConfig{Mode: machine.PinOutput})
 
 	// timer fires 10 times per second
-	arm.SetupSystemTimer(machine.CPU_FREQUENCY / 10)
+	arm.SetupSystemTimer(machine.CPUFrequency() / 10)
 
 	for {
 	}

src/machine/board_arduino.go

@@ -2,7 +2,10 @@
 
 package machine
 
-const CPU_FREQUENCY = 16000000
+// Return the current CPU frequency in hertz.
+func CPUFrequency() uint32 {
+	return 16000000
+}
 
 // LED on the Arduino
 const LED Pin = 13

src/machine/board_arduino_nano33.go

@@ -1,4 +1,4 @@
-// +build sam,atsamd21,arduino_nano33
+// +build arduino_nano33
 
 // This contains the pin mappings for the Arduino Nano33 IoT board.
 //
@@ -6,8 +6,6 @@
 //
 package machine
 
-import "device/sam"
-
 // used to reset into bootloader
 const RESET_MAGIC_VALUE = 0x07738135
 
@@ -54,69 +52,23 @@ const (
 	USBCDC_DP_PIN Pin = PA25
 )
 
-// UART1 on the Arduino Nano 33 connects to the onboard NINA-W102 WiFi chip.
-var (
-	UART1 = UART{
-		Buffer: NewRingBuffer(),
-		Bus:    sam.SERCOM5_USART,
-		SERCOM: 5,
-	}
-)
-
 // UART1 pins
 const (
 	UART_TX_PIN Pin = PA22
 	UART_RX_PIN Pin = PA23
 )
 
-//go:export SERCOM5_IRQHandler
-func handleUART1() {
-	defaultUART1Handler()
-}
-
-// UART2 on the Arduino Nano 33 connects to the normal TX/RX pins.
-var (
-	UART2 = UART{
-		Buffer: NewRingBuffer(),
-		Bus:    sam.SERCOM3_USART,
-		SERCOM: 3,
-	}
-)
-
-//go:export SERCOM3_IRQHandler
-func handleUART2() {
-	// should reset IRQ
-	UART2.Receive(byte((UART2.Bus.DATA.Get() & 0xFF)))
-	UART2.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
-}
-
 // I2C pins
 const (
 	SDA_PIN Pin = A4 // SDA: SERCOM4/PAD[1]
 	SCL_PIN Pin = A5 // SCL: SERCOM4/PAD[1]
 )
 
-// I2C on the Arduino Nano 33.
-var (
-	I2C0 = I2C{
-		Bus:    sam.SERCOM4_I2CM,
-		SERCOM: 4,
-	}
-)
-
 // SPI pins
 const (
-	SPI0_SCK_PIN  Pin = A2 // SCK: SERCOM0/PAD[3]
+	SPI0_SCK_PIN  Pin = D13 // SCK: SERCOM1/PAD[1]
-	SPI0_MOSI_PIN Pin = A3 // MOSI: SERCOM0/PAD[2]
+	SPI0_MOSI_PIN Pin = D11 // MOSI: SERCOM1/PAD[0]
-	SPI0_MISO_PIN Pin = A6 // MISO: SERCOM0/PAD[1]
+	SPI0_MISO_PIN Pin = D12 // MISO: SERCOM1/PAD[3]
-)
-
-// SPI on the Arduino Nano 33.
-var (
-	SPI0 = SPI{
-		Bus:    sam.SERCOM0_SPI,
-		SERCOM: 0,
-	}
 )
 
 // NINA-W102 Pins
@@ -132,23 +84,9 @@ const (
 	NINA_RX     Pin = PA23
 )
 
-// SPI1 is connected to the NINA-W102 chip on the Arduino Nano 33.
-var (
-	SPI1 = SPI{
-		Bus:    sam.SERCOM2_SPI,
-		SERCOM: 2,
-	}
-	NINA_SPI = SPI1
-)
-
 // I2S pins
 const (
 	I2S_SCK_PIN Pin = PA10
 	I2S_SD_PIN  Pin = PA08
 	I2S_WS_PIN      = NoPin // TODO: figure out what this is on Arduino Nano 33.
 )
-
-// I2S on the Arduino Nano 33.
-var (
-	I2S0 = I2S{Bus: sam.I2S}
-)

src/machine/board_arduino_nano33_baremetal.go

@@ -0,0 +1,62 @@
+// +build sam,atsamd21,arduino_nano33
+
+package machine
+
+import (
+	"device/sam"
+	"runtime/interrupt"
+)
+
+// UART1 on the Arduino Nano 33 connects to the onboard NINA-W102 WiFi chip.
+var (
+	UART1 = UART{
+		Buffer: NewRingBuffer(),
+		Bus:    sam.SERCOM3_USART,
+		SERCOM: 3,
+	}
+)
+
+// UART2 on the Arduino Nano 33 connects to the normal TX/RX pins.
+var (
+	UART2 = UART{
+		Buffer: NewRingBuffer(),
+		Bus:    sam.SERCOM5_USART,
+		SERCOM: 5,
+	}
+)
+
+func init() {
+	// Work around circular definitions.
+	UART1.interrupt = interrupt.New(sam.IRQ_SERCOM3, UART1.handleInterrupt)
+	UART2.interrupt = interrupt.New(sam.IRQ_SERCOM5, UART2.handleInterrupt)
+}
+
+// I2C on the Arduino Nano 33.
+var (
+	I2C0 = I2C{
+		Bus:    sam.SERCOM4_I2CM,
+		SERCOM: 4,
+	}
+)
+
+// SPI on the Arduino Nano 33.
+var (
+	SPI0 = SPI{
+		Bus:    sam.SERCOM1_SPI,
+		SERCOM: 1,
+	}
+)
+
+// SPI1 is connected to the NINA-W102 chip on the Arduino Nano 33.
+var (
+	SPI1 = SPI{
+		Bus:    sam.SERCOM2_SPI,
+		SERCOM: 2,
+	}
+	NINA_SPI = SPI1
+)
+
+// I2S on the Arduino Nano 33.
+var (
+	I2S0 = I2S{Bus: sam.I2S}
+)

src/machine/board_atsamd21.go

@@ -0,0 +1,76 @@
+// +build sam,atsamd21 arduino_nano33 circuitplay_express
+
+package machine
+
+// Return the current CPU frequency in hertz.
+func CPUFrequency() uint32 {
+	return 48000000
+}
+
+// Hardware pins
+const (
+	PA00 Pin = 0
+	PA01 Pin = 1
+	PA02 Pin = 2
+	PA03 Pin = 3
+	PA04 Pin = 4
+	PA05 Pin = 5
+	PA06 Pin = 6
+	PA07 Pin = 7
+	PA08 Pin = 8
+	PA09 Pin = 9
+	PA10 Pin = 10
+	PA11 Pin = 11
+	PA12 Pin = 12
+	PA13 Pin = 13
+	PA14 Pin = 14
+	PA15 Pin = 15
+	PA16 Pin = 16
+	PA17 Pin = 17
+	PA18 Pin = 18
+	PA19 Pin = 19
+	PA20 Pin = 20
+	PA21 Pin = 21
+	PA22 Pin = 22
+	PA23 Pin = 23
+	PA24 Pin = 24
+	PA25 Pin = 25
+	PA26 Pin = 26
+	PA27 Pin = 27
+	PA28 Pin = 28
+	PA29 Pin = 29
+	PA30 Pin = 30
+	PA31 Pin = 31
+	PB00 Pin = 32
+	PB01 Pin = 33
+	PB02 Pin = 34
+	PB03 Pin = 35
+	PB04 Pin = 36
+	PB05 Pin = 37
+	PB06 Pin = 38
+	PB07 Pin = 39
+	PB08 Pin = 40
+	PB09 Pin = 41
+	PB10 Pin = 42
+	PB11 Pin = 43
+	PB12 Pin = 44
+	PB13 Pin = 45
+	PB14 Pin = 46
+	PB15 Pin = 47
+	PB16 Pin = 48
+	PB17 Pin = 49
+	PB18 Pin = 50
+	PB19 Pin = 51
+	PB20 Pin = 52
+	PB21 Pin = 53
+	PB22 Pin = 54
+	PB23 Pin = 55
+	PB24 Pin = 56
+	PB25 Pin = 57
+	PB26 Pin = 58
+	PB27 Pin = 59
+	PB28 Pin = 60
+	PB29 Pin = 61
+	PB30 Pin = 62
+	PB31 Pin = 63
+)

src/machine/board_bluepill.go

@@ -2,7 +2,10 @@
 
 package machine
 
-import "device/stm32"
+import (
+	"device/stm32"
+	"runtime/interrupt"
+)
 
 // https://wiki.stm32duino.com/index.php?title=File:Bluepillpinout.gif
 const (
@@ -61,14 +64,12 @@ var (
 	UART0 = UART{
 		Buffer: NewRingBuffer(),
 		Bus:    stm32.USART1,
-		IRQVal: stm32.IRQ_USART1,
 	}
 	UART1 = &UART0
 )
 
-//go:export USART1_IRQHandler
+func init() {
-func handleUART1() {
+	UART0.interrupt = interrupt.New(stm32.IRQ_USART1, UART0.handleInterrupt)
-	UART1.Receive(byte((UART1.Bus.DR.Get() & 0xFF)))
 }
 
 // SPI pins

src/machine/board_circuitplay_express.go

@@ -1,9 +1,7 @@
-// +build sam,atsamd21,circuitplay_express
+// +build circuitplay_express
 
 package machine
 
-import "device/sam"
-
 // used to reset into bootloader
 const RESET_MAGIC_VALUE = 0xf01669ef
 
@@ -68,20 +66,6 @@ const (
 	UART_RX_PIN = PB09 // PORTB
 )
 
-// UART1 on the Circuit Playground Express.
-var (
-	UART1 = UART{
-		Buffer: NewRingBuffer(),
-		Bus:    sam.SERCOM4_USART,
-		SERCOM: 4,
-	}
-)
-
-//go:export SERCOM1_IRQHandler
-func handleUART1() {
-	defaultUART1Handler()
-}
-
 // I2C pins
 const (
 	SDA_PIN = PB02 // I2C0 external
@@ -91,20 +75,6 @@ const (
 	SCL1_PIN = PA01 // I2C1 internal
 )
 
-// I2C on the Circuit Playground Express.
-var (
-	// external device
-	I2C0 = I2C{
-		Bus:    sam.SERCOM5_I2CM,
-		SERCOM: 5,
-	}
-	// internal device
-	I2C1 = I2C{
-		Bus:    sam.SERCOM1_I2CM,
-		SERCOM: 1,
-	}
-)
-
 // SPI pins (internal flash)
 const (
 	SPI0_SCK_PIN  = PA21 // SCK: SERCOM3/PAD[3]
@@ -112,22 +82,9 @@ const (
 	SPI0_MISO_PIN = PA16 // MISO: SERCOM3/PAD[0]
 )
 
-// SPI on the Circuit Playground Express.
-var (
-	SPI0 = SPI{
-		Bus:    sam.SERCOM3_SPI,
-		SERCOM: 3,
-	}
-)
-
 // I2S pins
 const (
 	I2S_SCK_PIN = PA10
 	I2S_SD_PIN  = PA08
 	I2S_WS_PIN  = NoPin // no WS, instead uses SCK to sync
 )
-
-// I2S on the Circuit Playground Express.
-var (
-	I2S0 = I2S{Bus: sam.I2S}
-)

src/machine/board_circuitplay_express_baremetal.go

@@ -0,0 +1,48 @@
+// +build sam,atsamd21,circuitplay_express
+
+package machine
+
+import (
+	"device/sam"
+	"runtime/interrupt"
+)
+
+// UART1 on the Circuit Playground Express.
+var (
+	UART1 = UART{
+		Buffer: NewRingBuffer(),
+		Bus:    sam.SERCOM4_USART,
+		SERCOM: 4,
+	}
+)
+
+func init() {
+	UART1.interrupt = interrupt.New(sam.IRQ_SERCOM4, UART1.handleInterrupt)
+}
+
+// I2C on the Circuit Playground Express.
+var (
+	// external device
+	I2C0 = I2C{
+		Bus:    sam.SERCOM5_I2CM,
+		SERCOM: 5,
+	}
+	// internal device
+	I2C1 = I2C{
+		Bus:    sam.SERCOM1_I2CM,
+		SERCOM: 1,
+	}
+)
+
+// SPI on the Circuit Playground Express.
+var (
+	SPI0 = SPI{
+		Bus:    sam.SERCOM3_SPI,
+		SERCOM: 3,
+	}
+)
+
+// I2S on the Circuit Playground Express.
+var (
+	I2S0 = I2S{Bus: sam.I2S}
+)

src/machine/board_feather-m0.go

@@ -2,7 +2,10 @@
 
 package machine
 
-import "device/sam"
+import (
+	"device/sam"
+	"runtime/interrupt"
+)
 
 // used to reset into bootloader
 const RESET_MAGIC_VALUE = 0xf01669ef
@@ -60,9 +63,8 @@ var (
 	}
 )
 
-//go:export SERCOM1_IRQHandler
+func init() {
-func handleUART1() {
+	UART1.interrupt = interrupt.New(sam.IRQ_SERCOM1, UART1.handleInterrupt)
-	defaultUART1Handler()
 }
 
 // I2C pins

src/machine/board_itsybitsy-m0.go

@@ -4,6 +4,7 @@ package machine
 
 import (
 	"device/sam"
+	"runtime/interrupt"
 )
 
 // used to reset into bootloader
@@ -62,9 +63,8 @@ var (
 	}
 )
 
-//go:export SERCOM1_IRQHandler
+func init() {
-func handleUART1() {
+	UART1.interrupt = interrupt.New(sam.IRQ_SERCOM1, UART1.handleInterrupt)
-	defaultUART1Handler()
 }
 
 // I2C pins

src/machine/board_nucleof103rb.go

@@ -2,7 +2,10 @@
 
 package machine
 
-import "device/stm32"
+import (
+	"device/stm32"
+	"runtime/interrupt"
+)
 
 const (
 	PA0  = portA + 0
@@ -100,14 +103,12 @@ var (
 	UART0 = UART{
 		Buffer: NewRingBuffer(),
 		Bus:    stm32.USART2,
-		IRQVal: stm32.IRQ_USART2,
 	}
 	UART2 = &UART0
 )
 
-//go:export USART2_IRQHandler
+func init() {
-func handleUART2() {
+	UART0.interrupt = interrupt.New(stm32.IRQ_USART2, UART0.handleInterrupt)
-	UART2.Receive(byte((UART2.Bus.DR.Get() & 0xFF)))
 }
 
 // SPI pins

src/machine/board_pybadge.go

@@ -0,0 +1,150 @@
+// +build sam,atsamd51,pybadge
+
+package machine
+
+import "device/sam"
+
+// used to reset into bootloader
+const RESET_MAGIC_VALUE = 0xf01669ef
+
+// GPIO Pins
+const (
+	D0  = PB17 // UART0 RX/PWM available
+	D1  = PB16 // UART0 TX/PWM available
+	D2  = PB03
+	D3  = PB02
+	D4  = PA14 // PWM available
+	D5  = PA16 // PWM available
+	D6  = PA18 // PWM available
+	D7  = PB14
+	D8  = PA15 // built-in neopixel
+	D9  = PA19 // PWM available
+	D10 = PA20 // can be used for PWM or UART1 TX
+	D11 = PA21 // can be used for PWM or UART1 RX
+	D12 = PA22 // PWM available
+	D13 = PA23 // PWM available
+)
+
+// Analog pins
+const (
+	A0 = PA02 // ADC/AIN[0]
+	A1 = PA05 // ADC/AIN[2]
+	A2 = PB08 // ADC/AIN[3]
+	A3 = PB09 // ADC/AIN[4]
+	A4 = PA04 // ADC/AIN[5]
+	A5 = PA06 // ADC/AIN[6]
+	A6 = PB01 // ADC/AIN[12]/VMEAS
+	A7 = PB04 // ADC/AIN[6]/LIGHT
+	A8 = D2   // ADC/AIN[14]
+	A9 = D3   // ADC/AIN[15]
+)
+
+const (
+	LED       = D13
+	NEOPIXELS = D8
+
+	LIGHTSENSOR = A7
+
+	BUTTON_LATCH = PB00
+	BUTTON_OUT   = PB30
+	BUTTON_CLK   = PB31
+
+	TFT_DC   = PB05
+	TFT_CS   = PB07
+	TFT_RST  = PA00
+	TFT_LITE = PA01
+
+	SPEAKER_ENABLE = PA27
+
+	QSPI_SCK    = PB10
+	QSPI_CS     = PB11
+	QSPI_DATA_1 = PA08
+	QSPI_DATA_2 = PA09
+	QSPI_DATA_3 = PA10
+	QSPI_DATA_4 = PA11
+)
+
+const (
+	BUTTON_LEFT_MASK   = 1
+	BUTTON_UP_MASK     = 2
+	BUTTON_DOWN_MASK   = 4
+	BUTTON_RIGHT_MASK  = 8
+	BUTTON_SELECT_MASK = 16
+	BUTTON_START_MASK  = 32
+	BUTTON_A_MASK      = 64
+	BUTTON_B_MASK      = 128
+)
+
+// UART0 aka USBCDC pins
+const (
+	USBCDC_DM_PIN = PA24
+	USBCDC_DP_PIN = PA25
+)
+
+// UART1 pins
+const (
+	UART_TX_PIN = D1
+	UART_RX_PIN = D0
+)
+
+// UART1 var is on SERCOM3, defined in atsamd51.go
+
+// UART2 pins
+const (
+	UART2_TX_PIN = A4
+	UART2_RX_PIN = A5
+)
+
+// UART2 var is on SERCOM0, defined in atsamd51.go
+
+// I2C pins
+const (
+	SDA_PIN = PA12 // SDA: SERCOM2/PAD[0]
+	SCL_PIN = PA13 // SCL: SERCOM2/PAD[1]
+)
+
+// I2C on the ItsyBitsy M4.
+var (
+	I2C0 = I2C{Bus: sam.SERCOM2_I2CM,
+		SDA:     SDA_PIN,
+		SCL:     SCL_PIN,
+		PinMode: PinSERCOM}
+)
+
+// SPI pins
+const (
+	SPI0_SCK_PIN  = PA17 // SCK: SERCOM1/PAD[1]
+	SPI0_MOSI_PIN = PB23 // MOSI: SERCOM1/PAD[3]
+	SPI0_MISO_PIN = PB22 // MISO: SERCOM1/PAD[2]
+)
+
+// SPI on the PyBadge.
+var (
+	SPI0 = SPI{Bus: sam.SERCOM1_SPIM,
+		SCK:         SPI0_SCK_PIN,
+		MOSI:        SPI0_MOSI_PIN,
+		MISO:        SPI0_MISO_PIN,
+		DOpad:       spiTXPad3SCK1,
+		DIpad:       sercomRXPad2,
+		MISOPinMode: PinSERCOM,
+		MOSIPinMode: PinSERCOM,
+		SCKPinMode:  PinSERCOM,
+	}
+)
+
+// TFT SPI pins
+const (
+	SPI1_SCK_PIN  = PB13 // SCK: SERCOM4/PAD[1]
+	SPI1_MOSI_PIN = PB15 // MOSI: SERCOM4/PAD[3]
+)
+
+// TFT SPI on the PyBadge.
+var (
+	SPI1 = SPI{Bus: sam.SERCOM4_SPIM,
+		SCK:         SPI1_SCK_PIN,
+		MOSI:        SPI1_MOSI_PIN,
+		DOpad:       spiTXPad3SCK1,
+		MOSIPinMode: PinSERCOM,
+		SCKPinMode:  PinSERCOM,
+	}
+)

src/machine/board_trinket.go

@@ -2,7 +2,10 @@
 
 package machine
 
-import "device/sam"
+import (
+	"device/sam"
+	"runtime/interrupt"
+)
 
 // used to reset into bootloader
 const RESET_MAGIC_VALUE = 0xf01669ef
@@ -51,9 +54,8 @@ var (
 	}
 )
 
-//go:export SERCOM1_IRQHandler
+func init() {
-func handleUART1() {
+	UART1.interrupt = interrupt.New(sam.IRQ_SERCOM0, UART1.handleInterrupt)
-	defaultUART1Handler()
 }
 
 // SPI pins

src/machine/machine_atmega.go

@@ -4,6 +4,7 @@ package machine
 
 import (
 	"device/avr"
+	"runtime/interrupt"
 	"runtime/volatile"
 )
 
@@ -140,7 +141,7 @@ func (i2c I2C) Configure(config I2CConfig) {
 	// SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR))
 	// NOTE: TWBR should be 10 or higher for master mode.
 	// It is 72 for a 16mhz board with 100kHz TWI
-	avr.TWBR.Set(uint8(((CPU_FREQUENCY / config.Frequency) - 16) / 2))
+	avr.TWBR.Set(uint8(((CPUFrequency() / config.Frequency) - 16) / 2))
 
 	// Enable twi module.
 	avr.TWCR.Set(avr.TWCR_TWEN)
@@ -232,10 +233,22 @@ func (uart UART) Configure(config UARTConfig) {
 		config.BaudRate = 9600
 	}
 
+	// Register the UART interrupt.
+	interrupt.New(avr.IRQ_USART_RX, func(intr interrupt.Interrupt) {
+		// Read register to clear it.
+		data := avr.UDR0.Get()
+
+		// Ensure no error.
+		if !avr.UCSR0A.HasBits(avr.UCSR0A_FE0 | avr.UCSR0A_DOR0 | avr.UCSR0A_UPE0) {
+			// Put data from UDR register into buffer.
+			UART0.Receive(byte(data))
+		}
+	})
+
 	// Set baud rate based on prescale formula from
 	// https://www.microchip.com/webdoc/AVRLibcReferenceManual/FAQ_1faq_wrong_baud_rate.html
 	// ((F_CPU + UART_BAUD_RATE * 8L) / (UART_BAUD_RATE * 16L) - 1)
-	ps := ((CPU_FREQUENCY+config.BaudRate*8)/(config.BaudRate*16) - 1)
+	ps := ((CPUFrequency()+config.BaudRate*8)/(config.BaudRate*16) - 1)
 	avr.UBRR0H.Set(uint8(ps >> 8))
 	avr.UBRR0L.Set(uint8(ps & 0xff))
 
@@ -254,15 +267,3 @@ func (uart UART) WriteByte(c byte) error {
 	avr.UDR0.Set(c) // send char
 	return nil
 }
-
-//go:interrupt USART_RX_vect
-func handleUSART_RX() {
-	// Read register to clear it.
-	data := avr.UDR0.Get()
-
-	// Ensure no error.
-	if !avr.UCSR0A.HasBits(avr.UCSR0A_FE0 | avr.UCSR0A_DOR0 | avr.UCSR0A_UPE0) {
-		// Put data from UDR register into buffer.
-		UART0.Receive(byte(data))
-	}
-}

src/machine/machine_atsamd21.go

@@ -11,11 +11,10 @@ import (
 	"device/arm"
 	"device/sam"
 	"errors"
+	"runtime/interrupt"
 	"unsafe"
 )
 
-const CPU_FREQUENCY = 48000000
-
 type PinMode uint8
 
 const (
@@ -35,74 +34,6 @@ const (
 	PinInputPulldown PinMode = 12
 )
 
-// Hardware pins
-const (
-	PA00 Pin = 0
-	PA01 Pin = 1
-	PA02 Pin = 2
-	PA03 Pin = 3
-	PA04 Pin = 4
-	PA05 Pin = 5
-	PA06 Pin = 6
-	PA07 Pin = 7
-	PA08 Pin = 8
-	PA09 Pin = 9
-	PA10 Pin = 10
-	PA11 Pin = 11
-	PA12 Pin = 12
-	PA13 Pin = 13
-	PA14 Pin = 14
-	PA15 Pin = 15
-	PA16 Pin = 16
-	PA17 Pin = 17
-	PA18 Pin = 18
-	PA19 Pin = 19
-	PA20 Pin = 20
-	PA21 Pin = 21
-	PA22 Pin = 22
-	PA23 Pin = 23
-	PA24 Pin = 24
-	PA25 Pin = 25
-	PA26 Pin = 26
-	PA27 Pin = 27
-	PA28 Pin = 28
-	PA29 Pin = 29
-	PA30 Pin = 30
-	PA31 Pin = 31
-	PB00 Pin = 32
-	PB01 Pin = 33
-	PB02 Pin = 34
-	PB03 Pin = 35
-	PB04 Pin = 36
-	PB05 Pin = 37
-	PB06 Pin = 38
-	PB07 Pin = 39
-	PB08 Pin = 40
-	PB09 Pin = 41
-	PB10 Pin = 42
-	PB11 Pin = 43
-	PB12 Pin = 44
-	PB13 Pin = 45
-	PB14 Pin = 46
-	PB15 Pin = 47
-	PB16 Pin = 48
-	PB17 Pin = 49
-	PB18 Pin = 50
-	PB19 Pin = 51
-	PB20 Pin = 52
-	PB21 Pin = 53
-	PB22 Pin = 54
-	PB23 Pin = 55
-	PB24 Pin = 56
-	PB25 Pin = 57
-	PB26 Pin = 58
-	PB27 Pin = 59
-	PB28 Pin = 60
-	PB29 Pin = 61
-	PB30 Pin = 62
-	PB31 Pin = 63
-)
-
 const (
 	pinPadMapSERCOM0Pad0 byte = (0x10 << 1) | 0x00
 	pinPadMapSERCOM1Pad0 byte = (0x20 << 1) | 0x00
@@ -365,6 +296,7 @@ type UART struct {
 	Buffer    *RingBuffer
 	Bus       *sam.SERCOM_USART_Type
 	SERCOM    uint8
+	interrupt interrupt.Interrupt
 }
 
 var (
@@ -471,10 +403,7 @@ func (uart UART) Configure(config UARTConfig) error {
 	uart.Bus.INTENSET.Set(sam.SERCOM_USART_INTENSET_RXC)
 
 	// Enable RX IRQ.
-	// IRQ lines are in the same order as SERCOM instance numbers on SAMD21
+	uart.interrupt.Enable()
-	// chips, so the IRQ number can be trivially determined from the SERCOM
-	// number.
-	arm.EnableIRQ(sam.IRQ_SERCOM0 + uint32(uart.SERCOM))
 
 	return nil
 }
@@ -485,7 +414,7 @@ func (uart UART) SetBaudRate(br uint32) {
 	//   BAUD = fref / (sampleRateValue * fbaud)
 	// (multiply by 8, to calculate fractional piece)
 	// uint32_t baudTimes8 = (SystemCoreClock * 8) / (16 * baudrate);
-	baud := (CPU_FREQUENCY * 8) / (sampleRate16X * br)
+	baud := (CPUFrequency() * 8) / (sampleRate16X * br)
 
 	// sercom->USART.BAUD.FRAC.FP   = (baudTimes8 % 8);
 	// sercom->USART.BAUD.FRAC.BAUD = (baudTimes8 / 8);
@@ -502,11 +431,12 @@ func (uart UART) WriteByte(c byte) error {
 	return nil
 }
 
-// defaultUART1Handler handles the UART1 IRQ.
+// handleInterrupt should be called from the appropriate interrupt handler for
-func defaultUART1Handler() {
+// this UART instance.
+func (uart *UART) handleInterrupt(interrupt.Interrupt) {
 	// should reset IRQ
-	UART1.Receive(byte((UART1.Bus.DATA.Get() & 0xFF)))
+	uart.Receive(byte((uart.Bus.DATA.Get() & 0xFF)))
-	UART1.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
+	uart.Bus.INTFLAG.SetBits(sam.SERCOM_USART_INTFLAG_RXC)
 }
 
 // I2C on the SAMD21.
@@ -601,7 +531,7 @@ func (i2c I2C) Configure(config I2CConfig) error {
 func (i2c I2C) SetBaudRate(br uint32) {
 	// Synchronous arithmetic baudrate, via Arduino SAMD implementation:
 	// SystemCoreClock / ( 2 * baudrate) - 5 - (((SystemCoreClock / 1000000) * WIRE_RISE_TIME_NANOSECONDS) / (2 * 1000));
-	baud := CPU_FREQUENCY/(2*br) - 5 - (((CPU_FREQUENCY / 1000000) * riseTimeNanoseconds) / (2 * 1000))
+	baud := CPUFrequency()/(2*br) - 5 - (((CPUFrequency() / 1000000) * riseTimeNanoseconds) / (2 * 1000))
 	i2c.Bus.BAUD.Set(baud)
 }
 
@@ -793,7 +723,7 @@ func (i2s I2S) Configure(config I2SConfig) {
 	sam.PM.APBCMASK.SetBits(sam.PM_APBCMASK_I2S_)
 
 	// setting clock rate for sample.
-	division_factor := CPU_FREQUENCY / (config.AudioFrequency * uint32(config.DataFormat))
+	division_factor := CPUFrequency() / (config.AudioFrequency * uint32(config.DataFormat))
 
 	// Switch Generic Clock Generator 3 to DFLL48M.
 	sam.GCLK.GENDIV.Set((sam.GCLK_CLKCTRL_GEN_GCLK3 << sam.GCLK_GENDIV_ID_Pos) |
@@ -1113,7 +1043,7 @@ func (spi SPI) Configure(config SPIConfig) error {
 	}
 
 	// Set synch speed for SPI
-	baudRate := (CPU_FREQUENCY / (2 * config.Frequency)) - 1
+	baudRate := (CPUFrequency() / (2 * config.Frequency)) - 1
 	spi.Bus.BAUD.Set(uint8(baudRate))
 
 	// Enable SPI port.
@@ -1438,7 +1368,8 @@ func (usbcdc USBCDC) Configure(config UARTConfig) {
 	sam.USB_DEVICE.CTRLA.SetBits(sam.USB_DEVICE_CTRLA_ENABLE)
 
 	// enable IRQ
-	arm.EnableIRQ(sam.IRQ_USB)
+	intr := interrupt.New(sam.IRQ_USB, handleUSB)
+	intr.Enable()
 }
 
 func handlePadCalibration() {
@@ -1484,8 +1415,7 @@ func handlePadCalibration() {
 	sam.USB_DEVICE.PADCAL.SetBits(calibTrim << sam.USB_DEVICE_PADCAL_TRIM_Pos)
 }
 
-//go:export USB_IRQHandler
+func handleUSB(intr interrupt.Interrupt) {
-func handleUSB() {
 	// reset all interrupt flags
 	flags := sam.USB_DEVICE.INTFLAG.Get()
 	sam.USB_DEVICE.INTFLAG.Set(flags)

src/machine/machine_atsamd51.go

@@ -11,10 +11,13 @@ import (
 	"device/arm"
 	"device/sam"
 	"errors"
+	"runtime/interrupt"
 	"unsafe"
 )
 
-const CPU_FREQUENCY = 120000000
+func CPUFrequency() uint32 {
+	return 120000000
+}
 
 type PinMode uint8
 
@@ -1400,11 +1403,11 @@ func (usbcdc USBCDC) Configure(config UARTConfig) {
 	// enable USB
 	sam.USB_DEVICE.CTRLA.SetBits(sam.USB_DEVICE_CTRLA_ENABLE)
 
-	// enable IRQ
+	// enable IRQ at highest priority
-	arm.EnableIRQ(sam.IRQ_USB_OTHER)
+	interrupt.New(sam.IRQ_USB_OTHER, handleUSBIRQ).Enable()
-	arm.EnableIRQ(sam.IRQ_USB_SOF_HSOF)
+	interrupt.New(sam.IRQ_USB_SOF_HSOF, handleUSBIRQ).Enable()
-	arm.EnableIRQ(sam.IRQ_USB_TRCPT0)
+	interrupt.New(sam.IRQ_USB_TRCPT0, handleUSBIRQ).Enable()
-	arm.EnableIRQ(sam.IRQ_USB_TRCPT1)
+	interrupt.New(sam.IRQ_USB_TRCPT1, handleUSBIRQ).Enable()
 }
 
 func handlePadCalibration() {
@@ -1450,27 +1453,7 @@ func handlePadCalibration() {
 	sam.USB_DEVICE.PADCAL.SetBits(calibTrim << sam.USB_DEVICE_PADCAL_TRIM_Pos)
 }
 
-//go:export USB_OTHER_IRQHandler
+func handleUSBIRQ(interrupt.Interrupt) {
-func handleUSBOther() {
-	handleUSBIRQ()
-}
-
-//go:export USB_SOF_HSOF_IRQHandler
-func handleUSBSOFHSOF() {
-	handleUSBIRQ()
-}
-
-//go:export USB_TRCPT0_IRQHandler
-func handleUSBTRCPT0() {
-	handleUSBIRQ()
-}
-
-//go:export USB_TRCPT1_IRQHandler
-func handleUSBTRCPT1() {
-	handleUSBIRQ()
-}
-
-func handleUSBIRQ() {
 	// reset all interrupt flags
 	flags := sam.USB_DEVICE.INTFLAG.Get()
 	sam.USB_DEVICE.INTFLAG.Set(flags)

src/machine/machine_fe310.go

@@ -6,7 +6,9 @@ import (
 	"device/sifive"
 )
 
-const CPU_FREQUENCY = 16000000
+func CPUFrequency() uint32 {
+	return 16000000
+}
 
 type PinMode uint8
 
@@ -108,7 +110,7 @@ func (spi SPI) Configure(config SPIConfig) error {
 	}
 
 	// div = (SPI_CFG(dev)->f_sys / (2 * frequency)) - 1;
-	div := CPU_FREQUENCY/(2*config.Frequency) - 1
+	div := CPUFrequency()/(2*config.Frequency) - 1
 	spi.Bus.DIV.Set(div)
 
 	// set mode

src/machine/machine_nrf.go

@@ -3,9 +3,9 @@
 package machine
 
 import (
-	"device/arm"
 	"device/nrf"
 	"errors"
+	"runtime/interrupt"
 )
 
 var (
@@ -88,8 +88,11 @@ func (uart UART) Configure(config UARTConfig) {
 	nrf.UART0.INTENSET.Set(nrf.UART_INTENSET_RXDRDY_Msk)
 
 	// Enable RX IRQ.
-	arm.SetPriority(nrf.IRQ_UART0, 0xc0) // low priority
+	intr := interrupt.New(nrf.IRQ_UART0, func(intr interrupt.Interrupt) {
-	arm.EnableIRQ(nrf.IRQ_UART0)
+		UART0.handleInterrupt()
+	})
+	intr.SetPriority(0xc0) // low priority
+	intr.Enable()
 }
 
 // SetBaudRate sets the communication speed for the UART.

src/machine/machine_nrf51.go

@@ -6,7 +6,9 @@ import (
 	"device/nrf"
 )
 
-const CPU_FREQUENCY = 16000000
+func CPUFrequency() uint32 {
+	return 16000000
+}
 
 // Get peripheral and pin number for this GPIO pin.
 func (p Pin) getPortPin() (*nrf.GPIO_Type, uint32) {
@@ -18,11 +20,6 @@ func (uart UART) setPins(tx, rx Pin) {
 	nrf.UART0.PSELRXD.Set(uint32(rx))
 }
 
-//go:export UART0_IRQHandler
-func handleUART0() {
-	UART0.handleInterrupt()
-}
-
 func (i2c I2C) setPins(scl, sda Pin) {
 	i2c.Bus.PSELSCL.Set(uint32(scl))
 	i2c.Bus.PSELSDA.Set(uint32(sda))

src/machine/machine_nrf52.go

@@ -7,7 +7,9 @@ import (
 	"unsafe"
 )
 
-const CPU_FREQUENCY = 64000000
+func CPUFrequency() uint32 {
+	return 64000000
+}
 
 // Get peripheral and pin number for this GPIO pin.
 func (p Pin) getPortPin() (*nrf.GPIO_Type, uint32) {
@@ -19,11 +21,6 @@ func (uart UART) setPins(tx, rx Pin) {
 	nrf.UART0.PSELRXD.Set(uint32(rx))
 }
 
-//go:export UARTE0_UART0_IRQHandler
-func handleUART0() {
-	UART0.handleInterrupt()
-}
-
 func (i2c I2C) setPins(scl, sda Pin) {
 	i2c.Bus.PSELSCL.Set(uint32(scl))
 	i2c.Bus.PSELSDA.Set(uint32(sda))

src/machine/machine_nrf52840.go

@@ -7,7 +7,9 @@ import (
 	"unsafe"
 )
 
-const CPU_FREQUENCY = 64000000
+func CPUFrequency() uint32 {
+	return 64000000
+}
 
 // Get peripheral and pin number for this GPIO pin.
 func (p Pin) getPortPin() (*nrf.GPIO_Type, uint32) {
@@ -23,11 +25,6 @@ func (uart UART) setPins(tx, rx Pin) {
 	nrf.UART0.PSEL.RXD.Set(uint32(rx))
 }
 
-//go:export UARTE0_UART0_IRQHandler
-func handleUART0() {
-	UART0.handleInterrupt()
-}
-
 func (i2c I2C) setPins(scl, sda Pin) {
 	i2c.Bus.PSEL.SCL.Set(uint32(scl))
 	i2c.Bus.PSEL.SDA.Set(uint32(sda))

src/machine/machine_stm32f103xx.go

@@ -5,12 +5,14 @@ package machine
 // Peripheral abstraction layer for the stm32.
 
 import (
-	"device/arm"
 	"device/stm32"
 	"errors"
+	"runtime/interrupt"
 )
 
-const CPU_FREQUENCY = 72000000
+func CPUFrequency() uint32 {
+	return 72000000
+}
 
 const (
 	PinInput       PinMode = 0 // Input mode
@@ -111,7 +113,7 @@ func (p Pin) Get() bool {
 type UART struct {
 	Buffer    *RingBuffer
 	Bus       *stm32.USART_Type
-	IRQVal uint32
+	interrupt interrupt.Interrupt
 }
 
 // Configure the UART.
@@ -153,8 +155,8 @@ func (uart UART) Configure(config UARTConfig) {
 	uart.Bus.CR1.Set(stm32.USART_CR1_TE | stm32.USART_CR1_RE | stm32.USART_CR1_RXNEIE | stm32.USART_CR1_UE)
 
 	// Enable RX IRQ
-	arm.SetPriority(uart.IRQVal, 0xc0)
+	uart.interrupt.SetPriority(0xc0)
-	arm.EnableIRQ(uart.IRQVal)
+	uart.interrupt.Enable()
 }
 
 // SetBaudRate sets the communication speed for the UART.
@@ -163,10 +165,10 @@ func (uart UART) SetBaudRate(br uint32) {
 	var divider uint32
 	if uart.Bus == stm32.USART1 {
 		// first divide by PCLK2 prescaler (div 1) and then desired baudrate
-		divider = CPU_FREQUENCY / br
+		divider = CPUFrequency() / br
 	} else {
 		// first divide by PCLK1 prescaler (div 2) and then desired baudrate
-		divider = CPU_FREQUENCY / 2 / br
+		divider = CPUFrequency() / 2 / br
 	}
 	uart.Bus.BRR.Set(divider)
 }
@@ -180,6 +182,12 @@ func (uart UART) WriteByte(c byte) error {
 	return nil
 }
 
+// handleInterrupt should be called from the appropriate interrupt handler for
+// this UART instance.
+func (uart *UART) handleInterrupt(interrupt.Interrupt) {
+	uart.Receive(byte((uart.Bus.DR.Get() & 0xFF)))
+}
+
 // SPI on the STM32.
 type SPI struct {
 	Bus *stm32.SPI_Type
@@ -360,7 +368,7 @@ func (i2c I2C) Configure(config I2CConfig) {
 	i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_PE)
 
 	// pclk1 clock speed is main frequency divided by PCLK1 prescaler (div 2)
-	pclk1 := uint32(CPU_FREQUENCY / 2)
+	pclk1 := CPUFrequency() / 2
 
 	// set freqency range to PCLK1 clock speed in MHz
 	// aka setting the value 36 means to use 36 MHz clock

src/machine/machine_stm32f407.go

@@ -5,11 +5,13 @@ package machine
 // Peripheral abstraction layer for the stm32.
 
 import (
-	"device/arm"
 	"device/stm32"
+	"runtime/interrupt"
 )
 
-const CPU_FREQUENCY = 168000000
+func CPUFrequency() uint32 {
+	return 168000000
+}
 
 const (
 	// Mode Flag
@@ -201,8 +203,11 @@ func (uart UART) Configure(config UARTConfig) {
 	stm32.USART2.CR1.Set(stm32.USART_CR1_TE | stm32.USART_CR1_RE | stm32.USART_CR1_RXNEIE | stm32.USART_CR1_UE)
 
 	// Enable RX IRQ.
-	arm.SetPriority(stm32.IRQ_USART2, 0xc0)
+	intr := interrupt.New(stm32.IRQ_USART2, func(interrupt.Interrupt) {
-	arm.EnableIRQ(stm32.IRQ_USART2)
+		UART1.Receive(byte((stm32.USART2.DR.Get() & 0xFF)))
+	})
+	intr.SetPriority(0xc0)
+	intr.Enable()
 }
 
 // WriteByte writes a byte of data to the UART.
@@ -213,8 +218,3 @@ func (uart UART) WriteByte(c byte) error {
 	}
 	return nil
 }
-
-//go:export USART2_IRQHandler
-func handleUSART2() {
-	UART1.Receive(byte((stm32.USART2.DR.Get() & 0xFF)))
-}

src/machine/spi.go

@@ -1,4 +1,4 @@
-// +build sam stm32,!stm32f407 fe310
+// +build !baremetal sam stm32,!stm32f407 fe310
 
 package machine
 

src/os/file_unix.go

@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal
+// +build darwin linux,!baremetal freebsd,!baremetal
 
 package os
 

src/runtime/interrupt/interrupt.go

@@ -0,0 +1,14 @@
+// Package interrupt provides access to hardware interrupts. It provides a way
+// to define interrupts and to enable/disable them.
+package interrupt
+
+// Interrupt provides direct access to hardware interrupts. You can configure
+// this interrupt through this interface.
+//
+// Do not use the zero value of an Interrupt object. Instead, call New to obtain
+// an interrupt handle.
+type Interrupt struct {
+	// Make this number unexported so it cannot be set directly. This provides
+	// some encapsulation.
+	num int
+}

src/runtime/interrupt/interrupt_cortexm.go

@@ -0,0 +1,23 @@
+// +build cortexm
+
+package interrupt
+
+import (
+	"device/arm"
+)
+
+// Enable enables this interrupt. Right after calling this function, the
+// interrupt may be invoked if it was already pending.
+func (irq Interrupt) Enable() {
+	arm.EnableIRQ(uint32(irq.num))
+}
+
+// SetPriority sets the interrupt priority for this interrupt. A lower number
+// means a higher priority. Additionally, most hardware doesn't implement all
+// priority bits (only the uppoer bits).
+//
+// Examples: 0xff (lowest priority), 0xc0 (low priority), 0x00 (highest possible
+// priority).
+func (irq Interrupt) SetPriority(priority uint8) {
+	arm.SetPriority(uint32(irq.num), uint32(priority))
+}

src/runtime/interrupt/interrupt_gameboyadvance.go

@@ -0,0 +1,59 @@
+// +build gameboyadvance
+
+package interrupt
+
+import (
+	"runtime/volatile"
+	"unsafe"
+)
+
+var handlers = [14]func(Interrupt){}
+
+const (
+	IRQ_VBLANK  = 0
+	IRQ_HBLANK  = 1
+	IRQ_VCOUNT  = 2
+	IRQ_TIMER0  = 3
+	IRQ_TIMER1  = 4
+	IRQ_TIMER2  = 5
+	IRQ_TIMER3  = 6
+	IRQ_COM     = 7
+	IRQ_DMA0    = 8
+	IRQ_DMA1    = 9
+	IRQ_DMA2    = 10
+	IRQ_DMA3    = 11
+	IRQ_KEYPAD  = 12
+	IRQ_GAMEPAK = 13
+)
+
+var (
+	regInterruptEnable = (*volatile.Register16)(unsafe.Pointer(uintptr(0x4000200)))
+	regInterruptRequestFlags = (*volatile.Register16)(unsafe.Pointer(uintptr(0x4000202)))
+	regInterruptMasterEnable = (*volatile.Register16)(unsafe.Pointer(uintptr(0x4000208)))
+)
+
+// New creates a new Interrupt object. Do not call it multiple times. If you do,
+// make sure the interrupt is disabled while you do so. The last call will set
+// the active interrupt handler.
+func New(id int, handler func(Interrupt)) Interrupt {
+	handlers[id] = handler
+	return Interrupt{id}
+}
+
+// Enable enables this interrupt. Right after calling this function, the
+// interrupt may be invoked if it was already pending.
+func (irq Interrupt) Enable() {
+	regInterruptEnable.SetBits(1 << irq.num)
+}
+
+//export handleInterrupt
+func handleInterrupt() {
+	flags := regInterruptRequestFlags.Get()
+	for i := range handlers {
+		if flags & (1 << i) != 0 {
+			irq := Interrupt{i}
+			regInterruptRequestFlags.Set(1 << i) // acknowledge interrupt
+			handlers[i](irq)
+		}
+	}
+}

src/runtime/interrupt/interrupt_vectored.go

@@ -0,0 +1,19 @@
+// +build avr riscv,baremetal cortexm
+
+package interrupt
+
+// New is a compiler intrinsic that creates a new Interrupt object. You may call
+// it only once, and must pass constant parameters to it. That means that the
+// interrupt ID must be a Go constant and that the handler must be a simple
+// function: closures are not supported.
+func New(id int, handler func(Interrupt)) Interrupt
+
+// Register is used to declare an interrupt. You should not normally call this
+// function: it is only for telling the compiler about the mapping between an
+// interrupt number and the interrupt handler name.
+func Register(id int, handlerName string) int
+
+type handle struct {
+	handler func(Interrupt)
+	Interrupt
+}

src/runtime/os_freebsd.go

@@ -0,0 +1,5 @@
+// +build freebsd
+
+package runtime
+
+const GOOS = "freebsd"

src/runtime/runtime_arm7tdmi.go

@@ -4,6 +4,7 @@ package runtime
 
 import (
 	"unsafe"
+	_ "runtime/interrupt" // make sure the interrupt handler is defined
 )
 
 type timeUnit int64

src/runtime/runtime_atsamd21.go

@@ -6,6 +6,7 @@ import (
 	"device/arm"
 	"device/sam"
 	"machine"
+	"runtime/interrupt"
 	"runtime/volatile"
 	"unsafe"
 )
@@ -214,8 +215,14 @@ func initRTC() {
 	sam.RTC_MODE0.CTRL.SetBits(sam.RTC_MODE0_CTRL_ENABLE)
 	waitForSync()
 
-	arm.SetPriority(sam.IRQ_RTC, 0xc0)
+	intr := interrupt.New(sam.IRQ_RTC, func(intr interrupt.Interrupt) {
-	arm.EnableIRQ(sam.IRQ_RTC)
+		// disable IRQ for CMP0 compare
+		sam.RTC_MODE0.INTFLAG.Set(sam.RTC_MODE0_INTENSET_CMP0)
+
+		timerWakeup.Set(1)
+	})
+	intr.SetPriority(0xc0)
+	intr.Enable()
 }
 
 func waitForSync() {
@@ -286,14 +293,6 @@ func timerSleep(ticks uint32) {
 	}
 }
 
-//go:export RTC_IRQHandler
-func handleRTC() {
-	// disable IRQ for CMP0 compare
-	sam.RTC_MODE0.INTFLAG.Set(sam.RTC_MODE0_INTENSET_CMP0)
-
-	timerWakeup.Set(1)
-}
-
 func initUSBClock() {
 	// Turn on clock for USB
 	sam.PM.APBBMASK.SetBits(sam.PM_APBBMASK_USB_)

src/runtime/runtime_cortexm_qemu.go

@@ -1,4 +1,4 @@
-// +build qemu
+// +build cortexm,qemu
 
 package runtime
 

src/runtime/runtime_fe310.go

@@ -9,7 +9,6 @@ import (
 	"machine"
 	"unsafe"
 
-	"device/riscv"
 	"device/sifive"
 )
 
@@ -82,34 +81,4 @@ func putchar(c byte) {
 	machine.UART0.WriteByte(c)
 }
 
-func ticks() timeUnit {
-	// Combining the low bits and the high bits yields a time span of over 270
-	// years without counter rollover.
-	highBits := sifive.RTC.RTCHI.Get()
-	for {
-		lowBits := sifive.RTC.RTCLO.Get()
-		newHighBits := sifive.RTC.RTCHI.Get()
-		if newHighBits == highBits {
-			// High bits stayed the same.
-			return timeUnit(lowBits) | (timeUnit(highBits) << 32)
-		}
-		// Retry, because there was a rollover in the low bits (happening every
-		// 1.5 days).
-		highBits = newHighBits
-	}
-}
-
 const asyncScheduler = false
-
-func sleepTicks(d timeUnit) {
-	target := ticks() + d
-	for ticks() < target {
-	}
-}
-
-func abort() {
-	// lock up forever
-	for {
-		riscv.Asm("wfi")
-	}
-}

src/runtime/runtime_fe310_baremetal.go

@@ -0,0 +1,39 @@
+// +build fe310,!qemu
+
+package runtime
+
+import (
+	"device/riscv"
+	"device/sifive"
+)
+
+func abort() {
+	// lock up forever
+	for {
+		riscv.Asm("wfi")
+	}
+}
+
+func ticks() timeUnit {
+	// Combining the low bits and the high bits yields a time span of over 270
+	// years without counter rollover.
+	highBits := sifive.RTC.RTCHI.Get()
+	for {
+		lowBits := sifive.RTC.RTCLO.Get()
+		newHighBits := sifive.RTC.RTCHI.Get()
+		if newHighBits == highBits {
+			// High bits stayed the same.
+			println("bits:", highBits, lowBits)
+			return timeUnit(lowBits) | (timeUnit(highBits) << 32)
+		}
+		// Retry, because there was a rollover in the low bits (happening every
+		// 1.5 days).
+		highBits = newHighBits
+	}
+}
+
+func sleepTicks(d timeUnit) {
+	target := ticks() + d
+	for ticks() < target {
+	}
+}

src/runtime/runtime_fe310_qemu.go

@@ -0,0 +1,28 @@
+// +build fe310,qemu
+
+package runtime
+
+import (
+	"runtime/volatile"
+	"unsafe"
+)
+
+// Special memory-mapped device to exit tests, created by SiFive.
+var testExit = (*volatile.Register32)(unsafe.Pointer(uintptr(0x100000)))
+
+var timestamp timeUnit
+
+func abort() {
+	// Signal a successful exit.
+	testExit.Set(0x5555)
+}
+
+func ticks() timeUnit {
+	return timestamp
+}
+
+func sleepTicks(d timeUnit) {
+	// Note: QEMU doesn't seem to support the RTC peripheral at the time of
+	// writing so just simulate sleeping here.
+	timestamp += d
+}

src/runtime/runtime_nrf.go

@@ -6,6 +6,7 @@ import (
 	"device/arm"
 	"device/nrf"
 	"machine"
+	"runtime/interrupt"
 	"runtime/volatile"
 )
 
@@ -43,8 +44,13 @@ func initLFCLK() {
 
 func initRTC() {
 	nrf.RTC1.TASKS_START.Set(1)
-	arm.SetPriority(nrf.IRQ_RTC1, 0xc0) // low priority
+	intr := interrupt.New(nrf.IRQ_RTC1, func(intr interrupt.Interrupt) {
-	arm.EnableIRQ(nrf.IRQ_RTC1)
+		nrf.RTC1.INTENCLR.Set(nrf.RTC_INTENSET_COMPARE0)
+		nrf.RTC1.EVENTS_COMPARE[0].Set(0)
+		rtc_wakeup.Set(1)
+	})
+	intr.SetPriority(0xc0) // low priority
+	intr.Enable()
 }
 
 func putchar(c byte) {
@@ -96,10 +102,3 @@ func rtc_sleep(ticks uint32) {
 		arm.Asm("wfi")
 	}
 }
-
-//go:export RTC1_IRQHandler
-func handleRTC1() {
-	nrf.RTC1.INTENCLR.Set(nrf.RTC_INTENSET_COMPARE0)
-	nrf.RTC1.EVENTS_COMPARE[0].Set(0)
-	rtc_wakeup.Set(1)
-}

src/runtime/runtime_stm32f103xx.go

@@ -6,6 +6,7 @@ import (
 	"device/arm"
 	"device/stm32"
 	"machine"
+	"runtime/interrupt"
 	"runtime/volatile"
 )
 
@@ -101,8 +102,9 @@ func initRTC() {
 func initTIM() {
 	stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM3EN)
 
-	arm.SetPriority(stm32.IRQ_TIM3, 0xc3)
+	intr := interrupt.New(stm32.IRQ_TIM3, handleTIM3)
-	arm.EnableIRQ(stm32.IRQ_TIM3)
+	intr.SetPriority(0xc3)
+	intr.Enable()
 }
 
 const asyncScheduler = false
@@ -163,7 +165,7 @@ func timerSleep(ticks uint32) {
 	// The current scaling only supports a range of 200 usec to 6553 msec.
 
 	// prescale counter down from 72mhz to 10khz aka 0.1 ms frequency.
-	stm32.TIM3.PSC.Set(machine.CPU_FREQUENCY/10000 - 1) // 7199
+	stm32.TIM3.PSC.Set(machine.CPUFrequency()/10000 - 1) // 7199
 
 	// Set duty aka duration.
 	// STM32 dividers use n-1, i.e. n counts from 0 to n-1.
@@ -186,8 +188,7 @@ func timerSleep(ticks uint32) {
 	}
 }
 
-//go:export TIM3_IRQHandler
+func handleTIM3(interrupt.Interrupt) {
-func handleTIM3() {
 	if stm32.TIM3.SR.HasBits(stm32.TIM_SR_UIF) {
 		// Disable the timer.
 		stm32.TIM3.CR1.ClearBits(stm32.TIM_CR1_CEN)

src/runtime/runtime_stm32f407.go

@@ -6,6 +6,7 @@ import (
 	"device/arm"
 	"device/stm32"
 	"machine"
+	"runtime/interrupt"
 	"runtime/volatile"
 )
 
@@ -121,8 +122,9 @@ var timerWakeup volatile.Register8
 func initTIM3() {
 	stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_TIM3EN)
 
-	arm.SetPriority(stm32.IRQ_TIM3, 0xc3)
+	intr := interrupt.New(stm32.IRQ_TIM3, handleTIM3)
-	arm.EnableIRQ(stm32.IRQ_TIM3)
+	intr.SetPriority(0xc3)
+	intr.Enable()
 }
 
 // Enable the TIM7 clock.(tick count)
@@ -139,8 +141,9 @@ func initTIM7() {
 	// Enable the timer.
 	stm32.TIM7.CR1.SetBits(stm32.TIM_CR1_CEN)
 
-	arm.SetPriority(stm32.IRQ_TIM7, 0xc1)
+	intr := interrupt.New(stm32.IRQ_TIM7, handleTIM7)
-	arm.EnableIRQ(stm32.IRQ_TIM7)
+	intr.SetPriority(0xc1)
+	intr.Enable()
 }
 
 const asyncScheduler = false
@@ -183,8 +186,7 @@ func timerSleep(ticks uint32) {
 	}
 }
 
-//go:export TIM3_IRQHandler
+func handleTIM3(interrupt.Interrupt) {
-func handleTIM3() {
 	if stm32.TIM3.SR.HasBits(stm32.TIM_SR_UIF) {
 		// Disable the timer.
 		stm32.TIM3.CR1.ClearBits(stm32.TIM_CR1_CEN)
@@ -197,8 +199,7 @@ func handleTIM3() {
 	}
 }
 
-//go:export TIM7_IRQHandler
+func handleTIM7(interrupt.Interrupt) {
-func handleTIM7() {
 	if stm32.TIM7.SR.HasBits(stm32.TIM_SR_UIF) {
 		// clear the update flag
 		stm32.TIM7.SR.ClearBits(stm32.TIM_SR_UIF)

src/runtime/runtime_unix.go

@@ -1,4 +1,4 @@
-// +build darwin linux,!baremetal
+// +build darwin linux,!baremetal freebsd,!baremetal
 
 package runtime
 

src/runtime/runtime_wasm.go

@@ -76,3 +76,17 @@ func memset(ptr unsafe.Pointer, c byte, size uintptr) unsafe.Pointer {
 	}
 	return ptr
 }
+
+// Implement memmove for LLVM and compiler-rt.
+//go:export memmove
+func libc_memmove(dst, src unsafe.Pointer, size uintptr) unsafe.Pointer {
+	memmove(dst, src, size)
+	return dst
+}
+
+// Implement memcpy for LLVM and compiler-rt.
+//go:export memcpy
+func libc_memcpy(dst, src unsafe.Pointer, size uintptr) unsafe.Pointer {
+	memcpy(dst, src, size)
+	return dst
+}

targets/cortex-m-qemu.json

@@ -8,7 +8,7 @@
 	],
 	"linkerscript": "targets/lm3s6965.ld",
 	"extra-files": [
-		"targets/qemu.s"
+		"targets/cortex-m-qemu.s"
 	],
 	"emulator": ["qemu-system-arm", "-machine", "lm3s6965evb", "-semihosting", "-nographic", "-kernel"]
 }

targets/cortex-m-qemu.s

@@ -1,5 +1,5 @@
 // Generic Cortex-M interrupt vector.
-// This vector is used by the QEMU target.
+// This vector is used by the Cortex-M QEMU target.
 
 .syntax unified
 

targets/gameboy-advance.ld

@@ -1,16 +1,17 @@
 OUTPUT_ARCH(arm)
 ENTRY(_start)
 
+/* Note: iwram is reduced by 96 bytes because the last part of that RAM
+ * (starting at 0x03007FA0) is used for interrupt handling.
+ */
 MEMORY {
     ewram   : ORIGIN = 0x02000000, LENGTH = 256K   /* on-board work RAM (2 wait states) */
-    iwram   : ORIGIN = 0x03000000, LENGTH = 32K  /* in-chip work RAM (faster) */
+    iwram   : ORIGIN = 0x03000000, LENGTH = 32K-96 /* in-chip work RAM (faster) */
     rom     : ORIGIN = 0x08000000, LENGTH = 32M    /* flash ROM */
 }
 
-__iwram_top = ORIGIN(iwram) + LENGTH(iwram);;
+__stack_size_irq = 1K;
-_stack_size = 3K;
+__stack_size_usr = 2K;
-__sp_irq    = _stack_top;
-__sp_usr    = _stack_top - 1K;
 
 SECTIONS
 {
@@ -35,8 +36,10 @@ SECTIONS
     .stack (NOLOAD) :
     {
         . = ALIGN(4);
-        . += _stack_size;
+        __sp_irq = .;
-        _stack_top = .;
+        . += __stack_size_irq;
+        __sp_usr = .;
+        . += __stack_size_usr;
     } >iwram
 
     /* Start address (in flash) of .data, used by startup code. */

targets/gameboy-advance.s

@@ -17,9 +17,7 @@ _start:
     .byte   0x00,0x00              // Checksum (80000BEh)
 
 start_vector:
-    mov     r0, #0x4000000                 // REG_BASE
+    // Configure stacks
-    str     r0, [r0, #0x208]
-
     mov     r0, #0x12                      // Switch to IRQ Mode
     msr     cpsr, r0
     ldr     sp, =__sp_irq                  // Set IRQ stack
@@ -27,7 +25,21 @@ start_vector:
     msr     cpsr, r0
     ldr     sp, =__sp_usr                  // Set user stack
 
+    // Configure interrupt handler
+    mov     r0, #0x4000000                 // REG_BASE
+    ldr     r1, =handleInterruptARM
+    str     r1, [r0, #-4]                  // actually storing to 0x03007FFC due to mirroring
+
+    // Enable interrupts
+    mov     r1, #1
+    str     r1, [r0, #0x208]               // 0x04000208 Interrupt Master Enable
+
     // Jump to user code (switching to Thumb mode)
     ldr     r3, =main
     bx      r3
 
+// Small interrupt handler that immediately jumps to a function defined in the
+// program (in Thumb) for further processing.
+handleInterruptARM:
+    ldr     r0, =handleInterrupt
+    bx      r0

targets/hifive1-qemu.json

@@ -0,0 +1,6 @@
+{
+	"inherits": ["fe310"],
+	"build-tags": ["hifive1b", "qemu"],
+	"linkerscript": "targets/hifive1-qemu.ld",
+	"emulator": ["qemu-system-riscv32", "-machine", "sifive_e", "-nographic", "-kernel"]
+}

targets/hifive1-qemu.ld

@@ -0,0 +1,13 @@
+
+/* memory map:
+ * https://github.com/sifive/freedom-e-sdk/blob/v201908-branch/bsp/sifive-hifive1/metal.default.lds
+ */
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x20400000, LENGTH = 0x1fc00000
+    RAM (xrw)       : ORIGIN = 0x80000000, LENGTH = 0x4000
+}
+
+_stack_size = 2K;
+
+INCLUDE "targets/riscv.ld"

targets/pybadge.json

@@ -0,0 +1,8 @@
+{
+    "inherits": ["atsamd51j19a"],
+    "build-tags": ["sam", "atsamd51j19a", "pybadge"],
+    "flash-1200-bps-reset": "true",
+    "flash-method": "msd",
+    "msd-volume-name": "PYBADGEBOOT",
+    "msd-firmware-name": "arcade.uf2"
+}

targets/riscv.json

@@ -4,9 +4,11 @@
 	"goarch": "arm",
 	"build-tags": ["tinygo.riscv", "baremetal", "linux", "arm"],
 	"gc": "conservative",
-	"compiler": "riscv64-unknown-elf-gcc",
+	"compiler": "clang",
-	"linker": "riscv64-unknown-elf-ld",
+	"linker": "ld.lld",
+	"rtlib": "compiler-rt",
 	"cflags": [
+		"--target=riscv32--none",
 		"-march=rv32imac",
 		"-mabi=ilp32",
 		"-Os",
@@ -21,5 +23,6 @@
 	],
 	"extra-files": [
 		"src/device/riscv/start.S"
-	]
+	],
+	"gdb": "riscv64-unknown-elf-gdb"
 }