tools: process SVD files in parallel

This speeds up the generation of SVD files, for example as part of a package build (where parallelism may not be desired, or tools should auto-detect the number of threads to use).
2026-07-28 07:38:41 +00:00 · 2023-10-04 15:24:09 +02:00
84 changed files with 488 additions and 1510 deletions
@@ -5,7 +5,7 @@ commands:
    steps:
      - run:
          name: "Pull submodules"
-          command: git submodule update --init --recursive
+          command: git submodule update --init
  llvm-source-linux:
    steps:
      - restore_cache:
@@ -55,7 +55,7 @@ commands:
      - run:
          name: "Install apt dependencies"
          command: |
-            echo 'deb https://apt.llvm.org/bullseye/ llvm-toolchain-bullseye-<<parameters.llvm>> main' > /etc/apt/sources.list.d/llvm.list
+            echo 'deb https://apt.llvm.org/buster/ llvm-toolchain-buster-<<parameters.llvm>> main' > /etc/apt/sources.list.d/llvm.list
            wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
            apt-get update
            apt-get install --no-install-recommends -y \
@@ -69,8 +69,8 @@ commands:
      - build-binaryen-linux
      - restore_cache:
          keys:
-            - go-cache-v4-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
-            - go-cache-v4-{{ checksum "go.mod" }}
+            - go-cache-v3-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_PREVIOUS_BUILD_NUM }}
+            - go-cache-v3-{{ checksum "go.mod" }}
      - llvm-source-linux
      - run: go install -tags=llvm<<parameters.llvm>> .
      - restore_cache:
@@ -89,10 +89,10 @@ commands:
              # formatting of generated files.
              name: Check Go code formatting
              command: make fmt-check
-      - run: make gen-device -j4
+      - run: make gen-device
      - run: make smoketest XTENSA=0
      - save_cache:
-          key: go-cache-v4-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_BUILD_NUM }}
+          key: go-cache-v3-{{ checksum "go.mod" }}-{{ .Environment.CIRCLE_BUILD_NUM }}
          paths:
            - ~/.cache/go-build
            - /go/pkg/mod
@@ -100,18 +100,11 @@ commands:
 jobs:
  test-llvm15-go118:
    docker:
-      - image: golang:1.18-bullseye
+      - image: golang:1.18-buster
    steps:
      - test-linux:
          llvm: "15"
    resource_class: large
-  test-llvm17-go121:
-    docker:
-      - image: golang:1.21-bullseye
-    steps:
-      - test-linux:
-          llvm: "17"
-    resource_class: large

 workflows:
  test-all:
@@ -119,5 +112,3 @@ workflows:
      # This tests our lowest supported versions of Go and LLVM, to make sure at
      # least the smoke tests still pass.
      - test-llvm15-go118
-      # This tests the upcoming LLVM 17 support.
-      - test-llvm17-go121
@@ -88,7 +88,7 @@ jobs:
        if: steps.cache-wasi-libc.outputs.cache-hit != 'true'
        run: make wasi-libc
      - name: make gen-device
-        run: make -j3 gen-device
+        run: make gen-device
      - name: Test TinyGo
        shell: bash
        run: make test GOTESTFLAGS="-short"
@@ -116,21 +116,11 @@ jobs:
  test-macos-homebrew:
    name: homebrew-install
    runs-on: macos-latest
-    strategy:
-      matrix:
-        version: [16, 17]
    steps:
-      - name: Update Homebrew
-        run: brew update
-      - name: Fix Python symlinks
-        run: |
-          # Github runners have broken symlinks, so relink
-          # see: https://github.com/actions/setup-python/issues/577
-          brew unlink python
-          brew link --overwrite python
      - name: Install LLVM
+        shell: bash
        run: |
-          HOMEBREW_NO_AUTO_UPDATE=1 brew install llvm@${{ matrix.version }}
+          HOMEBREW_NO_AUTO_UPDATE=1 brew install llvm@16
      - name: Checkout
        uses: actions/checkout@v3
      - name: Install Go
@@ -138,13 +128,7 @@ jobs:
        with:
          go-version: '1.21'
          cache: true
-      - name: Build TinyGo (LLVM ${{ matrix.version }})
-        run: go install -tags=llvm${{ matrix.version }}
-      - name: Check binary
-        run: tinygo version
-      - name: Build TinyGo (default LLVM)
-        if: matrix.version == 16
+      - name: Build TinyGo
        run: go install
      - name: Check binary
-        if: matrix.version == 16
        run: tinygo version
@@ -140,8 +140,8 @@ jobs:
      - name: Install wasmtime
        run: |
          mkdir -p $HOME/.wasmtime $HOME/.wasmtime/bin
-          curl https://github.com/bytecodealliance/wasmtime/releases/download/v14.0.4/wasmtime-v14.0.4-x86_64-linux.tar.xz -o wasmtime-v14.0.4-x86_64-linux.tar.xz -SfL
-          tar -C $HOME/.wasmtime/bin --wildcards -xf wasmtime-v14.0.4-x86_64-linux.tar.xz --strip-components=1 wasmtime-v14.0.4-x86_64-linux/*
+          curl https://github.com/bytecodealliance/wasmtime/releases/download/v5.0.0/wasmtime-v5.0.0-x86_64-linux.tar.xz -o wasmtime-v5.0.0-x86_64-linux.tar.xz -SfL
+          tar -C $HOME/.wasmtime/bin --wildcards -xf wasmtime-v5.0.0-x86_64-linux.tar.xz --strip-components=1 wasmtime-v5.0.0-x86_64-linux/*
          echo "$HOME/.wasmtime/bin" >> $GITHUB_PATH
      - name: Download release artifact
        uses: actions/download-artifact@v3
@@ -187,8 +187,8 @@ jobs:
      - name: Install wasmtime
        run: |
          mkdir -p $HOME/.wasmtime $HOME/.wasmtime/bin
-          curl -L https://github.com/bytecodealliance/wasmtime/releases/download/v14.0.4/wasmtime-v14.0.4-x86_64-linux.tar.xz -o wasmtime-v14.0.4-x86_64-linux.tar.xz -SfL
-          tar -C $HOME/.wasmtime/bin --wildcards -xf wasmtime-v14.0.4-x86_64-linux.tar.xz --strip-components=1 wasmtime-v14.0.4-x86_64-linux/*
+          curl -L https://github.com/bytecodealliance/wasmtime/releases/download/v5.0.0/wasmtime-v5.0.0-x86_64-linux.tar.xz -o wasmtime-v5.0.0-x86_64-linux.tar.xz -SfL
+          tar -C $HOME/.wasmtime/bin --wildcards -xf wasmtime-v5.0.0-x86_64-linux.tar.xz --strip-components=1 wasmtime-v5.0.0-x86_64-linux/*
          echo "$HOME/.wasmtime/bin" >> $GITHUB_PATH
      - name: Restore LLVM source cache
        uses: actions/cache/restore@v3
@@ -255,7 +255,7 @@ jobs:
      - name: Build wasi-libc
        if: steps.cache-wasi-libc.outputs.cache-hit != 'true'
        run: make wasi-libc
-      - run: make gen-device -j4
+      - run: make gen-device
      - name: Test TinyGo
        run: make ASSERT=1 test
      - name: Build TinyGo
@@ -356,13 +356,13 @@ jobs:
        uses: actions/cache@v3
        id: cache-binaryen
        with:
-          key: binaryen-linux-${{ matrix.goarch }}-v3
+          key: binaryen-linux-${{ matrix.goarch }}-v1
          path: build/wasm-opt
      - name: Build Binaryen
        if: steps.cache-binaryen.outputs.cache-hit != 'true'
        run: |
          sudo apt-get install --no-install-recommends ninja-build
-          git submodule update --init --recursive lib/binaryen
+          git submodule update --init lib/binaryen
          make CROSS=${{ matrix.toolchain }} binaryen
      - name: Install fpm
        run: |
@@ -1,43 +0,0 @@
-name: Nix
-
-on:
-  pull_request:
-  push:
-    branches:
-      - dev
-      - release
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  nix-test:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v3
-      - name: Pull musl
-        run: |
-            git submodule update --init lib/musl
-      - name: Restore LLVM source cache
-        uses: actions/cache/restore@v3
-        id: cache-llvm-source
-        with:
-          key: llvm-source-16-linux-nix-v1
-          path: |
-            llvm-project/compiler-rt
-      - name: Download LLVM source
-        if: steps.cache-llvm-source.outputs.cache-hit != 'true'
-        run: make llvm-source
-      - name: Save LLVM source cache
-        uses: actions/cache/save@v3
-        if: steps.cache-llvm-source.outputs.cache-hit != 'true'
-        with:
-          key: ${{ steps.cache-llvm-source.outputs.cache-primary-key }}
-          path: |
-            llvm-project/compiler-rt
-      - uses: cachix/install-nix-action@v22
-      - name: Test
-        run: |
-          nix develop --ignore-environment --keep HOME --command bash -c "go install && ~/go/bin/tinygo version && ~/go/bin/tinygo build -o test ./testdata/cgo"
@@ -49,7 +49,7 @@ jobs:
          path: |
            ~/.cache/go-build
            ~/go/pkg/mod
-      - run: make gen-device -j4
+      - run: make gen-device
      - name: Download drivers repo
        run: git clone https://github.com/tinygo-org/drivers.git
      - name: Save HEAD
@@ -96,9 +96,9 @@ jobs:
        run: make wasi-libc
      - name: Install wasmtime
        run: |
-          scoop install wasmtime@14.0.4
+          scoop install wasmtime
      - name: make gen-device
-        run: make -j3 gen-device
+        run: make gen-device
      - name: Test TinyGo
        shell: bash
        run: make test GOTESTFLAGS="-short"
@@ -203,7 +203,7 @@ jobs:
      - name: Install Dependencies
        shell: bash
        run: |
-          scoop install binaryen && scoop install wasmtime@14.0.4
+          scoop install binaryen wasmtime
      - name: Checkout
        uses: actions/checkout@v3
      - name: Install Go
@@ -85,7 +85,7 @@ Now that we have a working static build, it's time to make a release tarball:

 If you did not clone the repository with the `--recursive` option, you will get errors until you initialize the project submodules:

-    git submodule update --init --recursive
+    git submodule update --init

 The release tarball is stored in build/release.tar.gz, and can be extracted with
 the following command (for example in ~/lib):
@@ -10,7 +10,7 @@ LLD_SRC ?= $(LLVM_PROJECTDIR)/lld

 # Try to autodetect LLVM build tools.
 # Versions are listed here in descending priority order.
-LLVM_VERSIONS = 17 16 15
+LLVM_VERSIONS = 16 15
 errifempty = $(if $(1),$(1),$(error $(2)))
 detect = $(shell which $(call errifempty,$(firstword $(foreach p,$(2),$(shell command -v $(p) 2> /dev/null && echo $(p)))),failed to locate $(1) at any of: $(2)))
 toolSearchPathsVersion = $(1)-$(2)
@@ -32,6 +32,9 @@ export GOROOT = $(shell $(GO) env GOROOT)
 # Flags to pass to go test.
 GOTESTFLAGS ?=

+# md5sum binary
+MD5SUM = md5sum
+
 # tinygo binary for tests
 TINYGO ?= $(call detect,tinygo,tinygo $(CURDIR)/build/tinygo)

@@ -127,14 +130,14 @@ ifeq ($(OS),Windows_NT)
    USE_SYSTEM_BINARYEN ?= 1

 else ifeq ($(shell uname -s),Darwin)
-    MD5SUM ?= md5
+    MD5SUM = md5

    CGO_LDFLAGS += -lxar

    USE_SYSTEM_BINARYEN ?= 1

 else ifeq ($(shell uname -s),FreeBSD)
-    MD5SUM ?= md5
+    MD5SUM = md5
    START_GROUP = -Wl,--start-group
    END_GROUP = -Wl,--end-group
 else
@@ -142,9 +145,6 @@ else
    END_GROUP = -Wl,--end-group
 endif

-# md5sum binary default, can be overridden by an environment variable
-MD5SUM ?= md5sum
-
 # Libraries that should be linked in for the statically linked Clang.
 CLANG_LIB_NAMES = clangAnalysis clangAST clangASTMatchers clangBasic clangCodeGen clangCrossTU clangDriver clangDynamicASTMatchers clangEdit clangExtractAPI clangFormat clangFrontend clangFrontendTool clangHandleCXX clangHandleLLVM clangIndex clangLex clangParse clangRewrite clangRewriteFrontend clangSema clangSerialization clangSupport clangTooling clangToolingASTDiff clangToolingCore clangToolingInclusions
 CLANG_LIBS = $(START_GROUP) $(addprefix -l,$(CLANG_LIB_NAMES)) $(END_GROUP) -lstdc++
@@ -190,7 +190,7 @@ gen-device: gen-device-stm32
 endif

 gen-device-avr:
-	@if [ ! -e lib/avr/README.md ]; then echo "Submodules have not been downloaded. Please download them using:\n  git submodule update --init --recursive"; exit 1; fi
+	@if [ ! -e lib/avr/README.md ]; then echo "Submodules have not been downloaded. Please download them using:\n  git submodule update --init"; exit 1; fi
 	$(GO) build -o ./build/gen-device-avr ./tools/gen-device-avr/
 	./build/gen-device-avr lib/avr/packs/atmega src/device/avr/
 	./build/gen-device-avr lib/avr/packs/tiny src/device/avr/
@@ -264,8 +264,8 @@ endif
 .PHONY: wasi-libc
 wasi-libc: lib/wasi-libc/sysroot/lib/wasm32-wasi/libc.a
 lib/wasi-libc/sysroot/lib/wasm32-wasi/libc.a:
-	@if [ ! -e lib/wasi-libc/Makefile ]; then echo "Submodules have not been downloaded. Please download them using:\n  git submodule update --init --recursive"; exit 1; fi
-	cd lib/wasi-libc && $(MAKE) -j4 EXTRA_CFLAGS="-O2 -g -DNDEBUG -mnontrapping-fptoint -msign-ext" MALLOC_IMPL=none CC="$(CLANG)" AR=$(LLVM_AR) NM=$(LLVM_NM)
+	@if [ ! -e lib/wasi-libc/Makefile ]; then echo "Submodules have not been downloaded. Please download them using:\n  git submodule update --init"; exit 1; fi
+	cd lib/wasi-libc && $(MAKE) -j4 EXTRA_CFLAGS="-O2 -g -DNDEBUG -mnontrapping-fptoint -msign-ext" MALLOC_IMPL=none CC=$(CLANG) AR=$(LLVM_AR) NM=$(LLVM_NM)

 # Check for Node.js used during WASM tests.
 NODEJS_VERSION := $(word 1,$(subst ., ,$(shell node -v | cut -c 2-)))
@@ -506,8 +506,6 @@ smoketest:
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=feather-rp2040      examples/watchdog
 	@$(MD5SUM) test.hex
-	$(TINYGO) build -size short -o test.hex -target=feather-rp2040      examples/device-id
-	@$(MD5SUM) test.hex
 	# test simulated boards on play.tinygo.org
 ifneq ($(WASM), 0)
 	$(TINYGO) build -size short -o test.wasm -tags=arduino              examples/blinky1
@@ -880,7 +878,7 @@ deb:
 	@mkdir -p build/release-deb/usr/local/lib
 	cp -ar build/release/tinygo build/release-deb/usr/local/lib/tinygo
 	ln -sf ../lib/tinygo/bin/tinygo build/release-deb/usr/local/bin/tinygo
-	fpm -f -s dir -t deb -n tinygo -a $(DEB_ARCH) -v $(shell grep "const version = " goenv/version.go | awk '{print $$NF}') -m '@tinygo-org' --description='TinyGo is a Go compiler for small places.' --license='BSD 3-Clause' --url=https://tinygo.org/ --deb-changelog CHANGELOG.md -p build/release.deb -C ./build/release-deb
+	fpm -f -s dir -t deb -n tinygo -a $(DEB_ARCH) -v $(shell grep "const Version = " goenv/version.go | awk '{print $$NF}') -m '@tinygo-org' --description='TinyGo is a Go compiler for small places.' --license='BSD 3-Clause' --url=https://tinygo.org/ --deb-changelog CHANGELOG.md -p build/release.deb -C ./build/release-deb

 ifneq ($(RELEASEONLY), 1)
 release: build/release
@@ -1,6 +1,6 @@
 # TinyGo - Go compiler for small places

-[![Linux](https://github.com/tinygo-org/tinygo/actions/workflows/linux.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/linux.yml) [![macOS](https://github.com/tinygo-org/tinygo/actions/workflows/build-macos.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/build-macos.yml) [![Windows](https://github.com/tinygo-org/tinygo/actions/workflows/windows.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/windows.yml) [![Docker](https://github.com/tinygo-org/tinygo/actions/workflows/docker.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/docker.yml) [![Nix](https://github.com/tinygo-org/tinygo/actions/workflows/nix.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/nix.yml) [![CircleCI](https://circleci.com/gh/tinygo-org/tinygo/tree/dev.svg?style=svg)](https://circleci.com/gh/tinygo-org/tinygo/tree/dev)
+[![Linux](https://github.com/tinygo-org/tinygo/actions/workflows/linux.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/linux.yml) [![macOS](https://github.com/tinygo-org/tinygo/actions/workflows/build-macos.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/build-macos.yml) [![Windows](https://github.com/tinygo-org/tinygo/actions/workflows/windows.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/windows.yml) [![Docker](https://github.com/tinygo-org/tinygo/actions/workflows/docker.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/tinygo/actions/workflows/docker.yml) [![CircleCI](https://circleci.com/gh/tinygo-org/tinygo/tree/dev.svg?style=svg)](https://circleci.com/gh/tinygo-org/tinygo/tree/dev)

 TinyGo is a Go compiler intended for use in small places such as microcontrollers, WebAssembly (wasm/wasi), and command-line tools.

@@ -114,30 +114,6 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		cacheDir = tmpdir
 	}

-	// Create default global values.
-	globalValues := map[string]map[string]string{
-		"runtime": {
-			"buildVersion": goenv.Version(),
-		},
-		"testing": {},
-	}
-	if config.TestConfig.CompileTestBinary {
-		// The testing.testBinary is set to "1" when in a test.
-		// This is needed for testing.Testing() to work correctly.
-		globalValues["testing"]["testBinary"] = "1"
-	}
-
-	// Copy over explicitly set global values, like
-	// -ldflags="-X main.Version="1.0"
-	for pkgPath, vals := range config.Options.GlobalValues {
-		if _, ok := globalValues[pkgPath]; !ok {
-			globalValues[pkgPath] = map[string]string{}
-		}
-		for k, v := range vals {
-			globalValues[pkgPath][k] = v
-		}
-	}
-
 	// Check for a libc dependency.
 	// As a side effect, this also creates the headers for the given libc, if
 	// the libc needs them.
@@ -192,7 +168,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		CodeModel:       config.CodeModel(),
 		RelocationModel: config.RelocationModel(),
 		SizeLevel:       sizeLevel,
-		TinyGoVersion:   goenv.Version(),
+		TinyGoVersion:   goenv.Version,

 		Scheduler:          config.Scheduler(),
 		AutomaticStackSize: config.AutomaticStackSize(),
@@ -211,7 +187,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 	defer machine.Dispose()

 	// Load entire program AST into memory.
-	lprogram, err := loader.Load(config, pkgName, types.Config{
+	lprogram, err := loader.Load(config, pkgName, config.ClangHeaders, types.Config{
 		Sizes: compiler.Sizes(machine),
 	})
 	if err != nil {
@@ -240,12 +216,34 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 	var packageJobs []*compileJob
 	packageActionIDJobs := make(map[string]*compileJob)

+	if config.Options.GlobalValues == nil {
+		config.Options.GlobalValues = make(map[string]map[string]string)
+	}
+	if config.Options.GlobalValues["runtime"]["buildVersion"] == "" {
+		version := goenv.Version
+		if strings.HasSuffix(goenv.Version, "-dev") && goenv.GitSha1 != "" {
+			version += "-" + goenv.GitSha1
+		}
+		if config.Options.GlobalValues["runtime"] == nil {
+			config.Options.GlobalValues["runtime"] = make(map[string]string)
+		}
+		config.Options.GlobalValues["runtime"]["buildVersion"] = version
+	}
+	if config.TestConfig.CompileTestBinary {
+		// The testing.testBinary is set to "1" when in a test.
+		// This is needed for testing.Testing() to work correctly.
+		if config.Options.GlobalValues["testing"] == nil {
+			config.Options.GlobalValues["testing"] = make(map[string]string)
+		}
+		config.Options.GlobalValues["testing"]["testBinary"] = "1"
+	}
+
 	var embedFileObjects []*compileJob
 	for _, pkg := range lprogram.Sorted() {
 		pkg := pkg // necessary to avoid a race condition

 		var undefinedGlobals []string
-		for name := range globalValues[pkg.Pkg.Path()] {
+		for name := range config.Options.GlobalValues[pkg.Pkg.Path()] {
 			undefinedGlobals = append(undefinedGlobals, name)
 		}
 		sort.Strings(undefinedGlobals)
@@ -573,7 +571,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe

 			// Run all optimization passes, which are much more effective now
 			// that the optimizer can see the whole program at once.
-			err := optimizeProgram(mod, config, globalValues)
+			err := optimizeProgram(mod, config)
 			if err != nil {
 				return err
 			}
@@ -662,7 +660,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		job := &compileJob{
 			description: "compile extra file " + path,
 			run: func(job *compileJob) error {
-				result, err := compileAndCacheCFile(abspath, tmpdir, config.CFlags(false), config.Options.PrintCommands)
+				result, err := compileAndCacheCFile(abspath, tmpdir, config.CFlags(), config.Options.PrintCommands)
 				job.result = result
 				return err
 			},
@@ -1042,7 +1040,7 @@ func createEmbedObjectFile(data, hexSum, sourceFile, sourceDir, tmpdir string, c
 // optimizeProgram runs a series of optimizations and transformations that are
 // needed to convert a program to its final form. Some transformations are not
 // optional and must be run as the compiler expects them to run.
-func optimizeProgram(mod llvm.Module, config *compileopts.Config, globalValues map[string]map[string]string) error {
+func optimizeProgram(mod llvm.Module, config *compileopts.Config) error {
 	err := interp.Run(mod, config.Options.InterpTimeout, config.DumpSSA())
 	if err != nil {
 		return err
@@ -1061,7 +1059,7 @@ func optimizeProgram(mod llvm.Module, config *compileopts.Config, globalValues m
 	}

 	// Insert values from -ldflags="-X ..." into the IR.
-	err = setGlobalValues(mod, globalValues)
+	err = setGlobalValues(mod, config.Options.GlobalValues)
 	if err != nil {
 		return err
 	}
@@ -8,6 +8,7 @@ import (
 	"testing"

 	"github.com/tinygo-org/tinygo/compileopts"
+	"github.com/tinygo-org/tinygo/goenv"
 	"tinygo.org/x/go-llvm"
 )

@@ -73,6 +74,7 @@ func TestClangAttributes(t *testing.T) {

 func testClangAttributes(t *testing.T, options *compileopts.Options) {
 	testDir := t.TempDir()
+	clangHeaderPath := getClangHeaderPath(goenv.Get("TINYGOROOT"))

 	ctx := llvm.NewContext()
 	defer ctx.Dispose()
@@ -82,8 +84,9 @@ func testClangAttributes(t *testing.T, options *compileopts.Options) {
 		t.Fatalf("could not load target: %s", err)
 	}
 	config := compileopts.Config{
-		Options: options,
-		Target:  target,
+		Options:      options,
+		Target:       target,
+		ClangHeaders: clangHeaderPath,
 	}

 	// Create a very simple C input file.
@@ -95,7 +98,7 @@ func testClangAttributes(t *testing.T, options *compileopts.Options) {

 	// Compile this file using Clang.
 	outpath := filepath.Join(testDir, "test.bc")
-	flags := append([]string{"-c", "-emit-llvm", "-o", outpath, srcpath}, config.CFlags(false)...)
+	flags := append([]string{"-c", "-emit-llvm", "-o", outpath, srcpath}, config.CFlags()...)
 	if config.GOOS() == "darwin" {
 		// Silence some warnings that happen when testing GOOS=darwin on
 		// something other than MacOS.
@@ -77,15 +77,6 @@ func ReadBuildID() ([]byte, error) {
 			}
 			return raw[4:], nil
 		}
-
-		// Normally we would have found a build ID by now. But not on Nix,
-		// unfortunately, because Nix adds -no_uuid for some reason:
-		// https://github.com/NixOS/nixpkgs/issues/178366
-		// Fall back to the same implementation that we use for Windows.
-		id, err := readRawGoBuildID(f, 32*1024)
-		if len(id) != 0 || err != nil {
-			return id, err
-		}
 	default:
 		// On other platforms (such as Windows) there isn't such a convenient
 		// build ID. Luckily, Go does have an equivalent of the build ID, which
@@ -97,31 +88,16 @@ func ReadBuildID() ([]byte, error) {
 		// directly. Luckily the build ID is always at the start of the file.
 		// For details, see:
 		// https://github.com/golang/go/blob/master/src/cmd/internal/buildid/buildid.go
-		id, err := readRawGoBuildID(f, 4096)
-		if len(id) != 0 || err != nil {
-			return id, err
+		fileStart := make([]byte, 4096)
+		_, err := io.ReadFull(f, fileStart)
+		index := bytes.Index(fileStart, []byte("\xff Go build ID: \""))
+		if index < 0 || index > len(fileStart)-103 {
+			return nil, fmt.Errorf("could not find build id in %s", err)
+		}
+		buf := fileStart[index : index+103]
+		if bytes.HasPrefix(buf, []byte("\xff Go build ID: \"")) && bytes.HasSuffix(buf, []byte("\"\n \xff")) {
+			return buf[len("\xff Go build ID: \"") : len(buf)-1], nil
 		}
 	}
-	return nil, fmt.Errorf("could not find build ID in %v", executable)
-}
-
-// The Go toolchain stores a build ID in the binary that we can use, as a
-// fallback if binary file specific build IDs can't be obtained.
-// This function reads that build ID from the binary.
-func readRawGoBuildID(f *os.File, prefixSize int) ([]byte, error) {
-	fileStart := make([]byte, prefixSize)
-	_, err := io.ReadFull(f, fileStart)
-	if err != nil {
-		return nil, fmt.Errorf("could not read build id from %s: %v", f.Name(), err)
-	}
-	index := bytes.Index(fileStart, []byte("\xff Go build ID: \""))
-	if index < 0 || index > len(fileStart)-103 {
-		return nil, fmt.Errorf("could not find build id in %s", f.Name())
-	}
-	buf := fileStart[index : index+103]
-	if bytes.HasPrefix(buf, []byte("\xff Go build ID: \"")) && bytes.HasSuffix(buf, []byte("\"\n \xff")) {
-		return buf[len("\xff Go build ID: \"") : len(buf)-1], nil
-	}
-
-	return nil, nil
+	return nil, fmt.Errorf("could not find build ID in %s", executable)
 }
@@ -33,10 +33,13 @@ func NewConfig(options *compileopts.Options) (*compileopts.Config, error) {
 		return nil, fmt.Errorf("requires go version 1.18 through 1.21, got go%d.%d", major, minor)
 	}

+	clangHeaderPath := getClangHeaderPath(goenv.Get("TINYGOROOT"))
+
 	return &compileopts.Config{
 		Options:        options,
 		Target:         spec,
 		GoMinorVersion: minor,
+		ClangHeaders:   clangHeaderPath,
 		TestConfig:     options.TestConfig,
 	}, nil
 }
@@ -0,0 +1,105 @@
+package builder
+
+import (
+	"errors"
+	"io/fs"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+
+	"tinygo.org/x/go-llvm"
+)
+
+// getClangHeaderPath returns the path to the built-in Clang headers. It tries
+// multiple locations, which should make it find the directory when installed in
+// various ways.
+func getClangHeaderPath(TINYGOROOT string) string {
+	// Check whether we're running from the source directory.
+	path := filepath.Join(TINYGOROOT, "llvm-project", "clang", "lib", "Headers")
+	if _, err := os.Stat(path); !errors.Is(err, fs.ErrNotExist) {
+		return path
+	}
+
+	// Check whether we're running from the installation directory.
+	path = filepath.Join(TINYGOROOT, "lib", "clang", "include")
+	if _, err := os.Stat(path); !errors.Is(err, fs.ErrNotExist) {
+		return path
+	}
+
+	// It looks like we are built with a system-installed LLVM. Do a last
+	// attempt: try to use Clang headers relative to the clang binary.
+	llvmMajor := strings.Split(llvm.Version, ".")[0]
+	for _, cmdName := range commands["clang"] {
+		binpath, err := exec.LookPath(cmdName)
+		if err == nil {
+			// This should be the command that will also be used by
+			// execCommand. To avoid inconsistencies, make sure we use the
+			// headers relative to this command.
+			binpath, err = filepath.EvalSymlinks(binpath)
+			if err != nil {
+				// Unexpected.
+				return ""
+			}
+			// Example executable:
+			//     /usr/lib/llvm-9/bin/clang
+			// Example include path:
+			//     /usr/lib/llvm-9/lib64/clang/9.0.1/include/
+			llvmRoot := filepath.Dir(filepath.Dir(binpath))
+			clangVersionRoot := filepath.Join(llvmRoot, "lib64", "clang")
+			dirs64, err64 := ioutil.ReadDir(clangVersionRoot)
+			// Example include path:
+			//     /usr/lib/llvm-9/lib/clang/9.0.1/include/
+			clangVersionRoot = filepath.Join(llvmRoot, "lib", "clang")
+			dirs32, err32 := ioutil.ReadDir(clangVersionRoot)
+			if err64 != nil && err32 != nil {
+				// Unexpected.
+				continue
+			}
+			dirnames := make([]string, len(dirs64)+len(dirs32))
+			dirCount := 0
+			for _, d := range dirs32 {
+				name := d.Name()
+				if name == llvmMajor || strings.HasPrefix(name, llvmMajor+".") {
+					dirnames[dirCount] = filepath.Join(llvmRoot, "lib", "clang", name)
+					dirCount++
+				}
+			}
+			for _, d := range dirs64 {
+				name := d.Name()
+				if name == llvmMajor || strings.HasPrefix(name, llvmMajor+".") {
+					dirnames[dirCount] = filepath.Join(llvmRoot, "lib64", "clang", name)
+					dirCount++
+				}
+			}
+			sort.Strings(dirnames)
+			// Check for the highest version first.
+			for i := dirCount - 1; i >= 0; i-- {
+				path := filepath.Join(dirnames[i], "include")
+				_, err := os.Stat(filepath.Join(path, "stdint.h"))
+				if err == nil {
+					return path
+				}
+			}
+		}
+	}
+
+	// On Arch Linux, the clang executable is stored in /usr/bin rather than being symlinked from there.
+	// Search directly in /usr/lib for clang.
+	if matches, err := filepath.Glob("/usr/lib/clang/" + llvmMajor + ".*.*"); err == nil {
+		// Check for the highest version first.
+		sort.Strings(matches)
+		for i := len(matches) - 1; i >= 0; i-- {
+			path := filepath.Join(matches[i], "include")
+			_, err := os.Stat(filepath.Join(path, "stdint.h"))
+			if err == nil {
+				return path
+			}
+		}
+	}
+
+	// Could not find it.
+	return ""
+}
@@ -143,10 +143,6 @@ func (l *Library) load(config *compileopts.Config, tmpdir string) (job *compileJ
 	// reproducible. Otherwise the temporary directory is stored in the archive
 	// itself, which varies each run.
 	args := append(l.cflags(target, headerPath), "-c", "-Oz", "-gdwarf-4", "-ffunction-sections", "-fdata-sections", "-Wno-macro-redefined", "--target="+target, "-fdebug-prefix-map="+dir+"="+remapDir)
-	resourceDir := goenv.ClangResourceDir(false)
-	if resourceDir != "" {
-		args = append(args, "-resource-dir="+resourceDir)
-	}
 	cpu := config.CPU()
 	if cpu != "" {
 		// X86 has deprecated the -mcpu flag, so we need to use -march instead.
@@ -3,7 +3,6 @@ package builder
 import (
 	"os"
 	"path/filepath"
-	"strings"

 	"github.com/tinygo-org/tinygo/goenv"
 )
@@ -42,23 +41,91 @@ var Picolibc = Library{
 	},
 	sourceDir: func() string { return filepath.Join(goenv.Get("TINYGOROOT"), "lib/picolibc/newlib") },
 	librarySources: func(target string) ([]string, error) {
-		sources := append([]string(nil), picolibcSources...)
-		if !strings.HasPrefix(target, "avr") {
-			// Small chips without long jumps can't compile many files (printf,
-			// pow, etc). Therefore exclude those source files for those chips.
-			// Unfortunately it's difficult to exclude only some chips, so this
-			// excludes those files on all AVR chips for now.
-			// More information:
-			// https://github.com/llvm/llvm-project/issues/67042
-			sources = append(sources, picolibcSourcesLarge...)
-		}
-		return sources, nil
+		return picolibcSources, nil
 	},
 }

 var picolibcSources = []string{
 	"../../picolibc-stdio.c",

+	// srcs_tinystdio
+	"libc/tinystdio/asprintf.c",
+	"libc/tinystdio/bufio.c",
+	"libc/tinystdio/clearerr.c",
+	"libc/tinystdio/ecvt_r.c",
+	"libc/tinystdio/ecvt.c",
+	"libc/tinystdio/ecvtf_r.c",
+	"libc/tinystdio/ecvtf.c",
+	"libc/tinystdio/fcvt.c",
+	"libc/tinystdio/fcvt_r.c",
+	"libc/tinystdio/fcvtf.c",
+	"libc/tinystdio/fcvtf_r.c",
+	"libc/tinystdio/gcvt.c",
+	"libc/tinystdio/gcvtf.c",
+	"libc/tinystdio/fclose.c",
+	"libc/tinystdio/fdevopen.c",
+	"libc/tinystdio/feof.c",
+	"libc/tinystdio/ferror.c",
+	"libc/tinystdio/fflush.c",
+	"libc/tinystdio/fgetc.c",
+	"libc/tinystdio/fgets.c",
+	"libc/tinystdio/fileno.c",
+	"libc/tinystdio/filestrget.c",
+	"libc/tinystdio/filestrput.c",
+	"libc/tinystdio/filestrputalloc.c",
+	"libc/tinystdio/fmemopen.c",
+	"libc/tinystdio/fprintf.c",
+	"libc/tinystdio/fputc.c",
+	"libc/tinystdio/fputs.c",
+	"libc/tinystdio/fread.c",
+	//"libc/tinystdio/freopen.c", // crashes with AVR, see: https://github.com/picolibc/picolibc/pull/369
+	"libc/tinystdio/fscanf.c",
+	"libc/tinystdio/fseek.c",
+	"libc/tinystdio/fseeko.c",
+	"libc/tinystdio/ftell.c",
+	"libc/tinystdio/ftello.c",
+	"libc/tinystdio/fwrite.c",
+	"libc/tinystdio/getchar.c",
+	"libc/tinystdio/gets.c",
+	"libc/tinystdio/matchcaseprefix.c",
+	"libc/tinystdio/mktemp.c",
+	"libc/tinystdio/perror.c",
+	"libc/tinystdio/printf.c",
+	"libc/tinystdio/putchar.c",
+	"libc/tinystdio/puts.c",
+	"libc/tinystdio/rewind.c",
+	"libc/tinystdio/scanf.c",
+	"libc/tinystdio/setbuf.c",
+	"libc/tinystdio/setbuffer.c",
+	"libc/tinystdio/setlinebuf.c",
+	"libc/tinystdio/setvbuf.c",
+	"libc/tinystdio/snprintf.c",
+	"libc/tinystdio/sprintf.c",
+	"libc/tinystdio/snprintfd.c",
+	"libc/tinystdio/snprintff.c",
+	"libc/tinystdio/sprintff.c",
+	"libc/tinystdio/sprintfd.c",
+	"libc/tinystdio/sscanf.c",
+	"libc/tinystdio/strfromf.c",
+	"libc/tinystdio/strfromd.c",
+	"libc/tinystdio/strtof.c",
+	"libc/tinystdio/strtof_l.c",
+	"libc/tinystdio/strtod.c",
+	"libc/tinystdio/strtod_l.c",
+	"libc/tinystdio/ungetc.c",
+	"libc/tinystdio/vasprintf.c",
+	"libc/tinystdio/vfiprintf.c",
+	"libc/tinystdio/vfprintf.c",
+	"libc/tinystdio/vfprintff.c",
+	"libc/tinystdio/vfscanf.c",
+	"libc/tinystdio/vfiscanf.c",
+	"libc/tinystdio/vfscanff.c",
+	"libc/tinystdio/vprintf.c",
+	"libc/tinystdio/vscanf.c",
+	"libc/tinystdio/vsscanf.c",
+	"libc/tinystdio/vsnprintf.c",
+	"libc/tinystdio/vsprintf.c",
+
 	"libc/string/bcmp.c",
 	"libc/string/bcopy.c",
 	"libc/string/bzero.c",
@@ -162,87 +229,6 @@ var picolibcSources = []string{
 	"libc/string/wmempcpy.c",
 	"libc/string/wmemset.c",
 	"libc/string/xpg_strerror_r.c",
-}
-
-// Parts of picolibc that are too large for small AVRs.
-var picolibcSourcesLarge = []string{
-	// srcs_tinystdio
-	"libc/tinystdio/asprintf.c",
-	"libc/tinystdio/bufio.c",
-	"libc/tinystdio/clearerr.c",
-	"libc/tinystdio/ecvt_r.c",
-	"libc/tinystdio/ecvt.c",
-	"libc/tinystdio/ecvtf_r.c",
-	"libc/tinystdio/ecvtf.c",
-	"libc/tinystdio/fcvt.c",
-	"libc/tinystdio/fcvt_r.c",
-	"libc/tinystdio/fcvtf.c",
-	"libc/tinystdio/fcvtf_r.c",
-	"libc/tinystdio/gcvt.c",
-	"libc/tinystdio/gcvtf.c",
-	"libc/tinystdio/fclose.c",
-	"libc/tinystdio/fdevopen.c",
-	"libc/tinystdio/feof.c",
-	"libc/tinystdio/ferror.c",
-	"libc/tinystdio/fflush.c",
-	"libc/tinystdio/fgetc.c",
-	"libc/tinystdio/fgets.c",
-	"libc/tinystdio/fileno.c",
-	"libc/tinystdio/filestrget.c",
-	"libc/tinystdio/filestrput.c",
-	"libc/tinystdio/filestrputalloc.c",
-	"libc/tinystdio/fmemopen.c",
-	"libc/tinystdio/fprintf.c",
-	"libc/tinystdio/fputc.c",
-	"libc/tinystdio/fputs.c",
-	"libc/tinystdio/fread.c",
-	//"libc/tinystdio/freopen.c", // crashes with AVR, see: https://github.com/picolibc/picolibc/pull/369
-	"libc/tinystdio/fscanf.c",
-	"libc/tinystdio/fseek.c",
-	"libc/tinystdio/fseeko.c",
-	"libc/tinystdio/ftell.c",
-	"libc/tinystdio/ftello.c",
-	"libc/tinystdio/fwrite.c",
-	"libc/tinystdio/getchar.c",
-	"libc/tinystdio/gets.c",
-	"libc/tinystdio/matchcaseprefix.c",
-	"libc/tinystdio/mktemp.c",
-	"libc/tinystdio/perror.c",
-	"libc/tinystdio/printf.c",
-	"libc/tinystdio/putchar.c",
-	"libc/tinystdio/puts.c",
-	"libc/tinystdio/rewind.c",
-	"libc/tinystdio/scanf.c",
-	"libc/tinystdio/setbuf.c",
-	"libc/tinystdio/setbuffer.c",
-	"libc/tinystdio/setlinebuf.c",
-	"libc/tinystdio/setvbuf.c",
-	"libc/tinystdio/snprintf.c",
-	"libc/tinystdio/sprintf.c",
-	"libc/tinystdio/snprintfd.c",
-	"libc/tinystdio/snprintff.c",
-	"libc/tinystdio/sprintff.c",
-	"libc/tinystdio/sprintfd.c",
-	"libc/tinystdio/sscanf.c",
-	"libc/tinystdio/strfromf.c",
-	"libc/tinystdio/strfromd.c",
-	"libc/tinystdio/strtof.c",
-	"libc/tinystdio/strtof_l.c",
-	"libc/tinystdio/strtod.c",
-	"libc/tinystdio/strtod_l.c",
-	"libc/tinystdio/ungetc.c",
-	"libc/tinystdio/vasprintf.c",
-	"libc/tinystdio/vfiprintf.c",
-	"libc/tinystdio/vfprintf.c",
-	"libc/tinystdio/vfprintff.c",
-	"libc/tinystdio/vfscanf.c",
-	"libc/tinystdio/vfiscanf.c",
-	"libc/tinystdio/vfscanff.c",
-	"libc/tinystdio/vprintf.c",
-	"libc/tinystdio/vscanf.c",
-	"libc/tinystdio/vsscanf.c",
-	"libc/tinystdio/vsnprintf.c",
-	"libc/tinystdio/vsprintf.c",

 	"libm/common/sf_finite.c",
 	"libm/common/sf_copysign.c",
@@ -1,6 +1,7 @@
 package builder

 import (
+	"errors"
 	"os"
 	"os/exec"

@@ -11,6 +12,11 @@ import (
 func runCCompiler(flags ...string) error {
 	if hasBuiltinTools {
 		// 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)
 		cmd := exec.Command(os.Args[0], append([]string{"clang"}, flags...)...)
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
@@ -165,7 +165,7 @@ func GoBytes(ptr unsafe.Pointer, length C.int) []byte {
 // functions), the CFLAGS and LDFLAGS found in #cgo lines, and a map of file
 // hashes of the accessed C header files. If there is one or more error, it
 // returns these in the []error slice but still modifies the AST.
-func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cflags []string) (*ast.File, []string, []string, []string, map[string][]byte, []error) {
+func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cflags []string, clangHeaders string) (*ast.File, []string, []string, []string, map[string][]byte, []error) {
 	p := &cgoPackage{
 		currentDir:      dir,
 		importPath:      importPath,
@@ -292,6 +292,9 @@ func Process(files []*ast.File, dir, importPath string, fset *token.FileSet, cfl
 	// have better alternatives anyway.
 	cflagsForCGo := append([]string{"-D_FORTIFY_SOURCE=0"}, cflags...)
 	cflagsForCGo = append(cflagsForCGo, p.cflags...)
+	if clangHeaders != "" {
+		cflagsForCGo = append(cflagsForCGo, "-isystem", clangHeaders)
+	}

 	// Retrieve types such as C.int, C.longlong, etc from C.
 	p.newCGoFile(nil, -1).readNames(builtinAliasTypedefs, cflagsForCGo, "", func(names map[string]clangCursor) {
@@ -55,7 +55,7 @@ func TestCGo(t *testing.T) {
 			}

 			// Process the AST with CGo.
-			cgoAST, _, _, _, _, cgoErrors := Process([]*ast.File{f}, "testdata", "main", fset, cflags)
+			cgoAST, _, _, _, _, cgoErrors := Process([]*ast.File{f}, "testdata", "main", fset, cflags, "")

 			// Check the AST for type errors.
 			var typecheckErrors []error
@@ -8,8 +8,8 @@ package cgo
 #cgo darwin,arm64 CFLAGS:  -I/opt/homebrew/opt/llvm@15/include
 #cgo freebsd      CFLAGS:  -I/usr/local/llvm15/include
 #cgo linux        LDFLAGS: -L/usr/lib/llvm-15/lib -lclang
-#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@15/lib -lclang
-#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@15/lib -lclang
+#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@15/lib -lclang -lffi
+#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@15/lib -lclang -lffi
 #cgo freebsd      LDFLAGS: -L/usr/local/llvm15/lib -lclang
 */
 import "C"
@@ -1,8 +1,8 @@
-//go:build !byollvm && !llvm15 && !llvm17
+//go:build !byollvm && !llvm15

 package cgo

-// As of 2023-05-05, there is a packaging issue with LLVM 16 on Debian:
+// As of 2023-05-05, there is a packaging issue on Debian:
 // https://github.com/llvm/llvm-project/issues/62199
 // A workaround is to fix this locally, using something like this:
 //
@@ -14,8 +14,8 @@ package cgo
 #cgo darwin,arm64 CFLAGS:  -I/opt/homebrew/opt/llvm@16/include
 #cgo freebsd      CFLAGS:  -I/usr/local/llvm16/include
 #cgo linux        LDFLAGS: -L/usr/lib/llvm-16/lib -lclang
-#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@16/lib -lclang
-#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@16/lib -lclang
+#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@16/lib -lclang -lffi
+#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@16/lib -lclang -lffi
 #cgo freebsd      LDFLAGS: -L/usr/local/llvm16/lib -lclang
 */
 import "C"
@@ -1,15 +0,0 @@
-//go:build !byollvm && llvm17
-
-package cgo
-
-/*
-#cgo linux        CFLAGS:  -I/usr/include/llvm-17 -I/usr/include/llvm-c-17 -I/usr/lib/llvm-17/include
-#cgo darwin,amd64 CFLAGS:  -I/usr/local/opt/llvm@17/include
-#cgo darwin,arm64 CFLAGS:  -I/opt/homebrew/opt/llvm@17/include
-#cgo freebsd      CFLAGS:  -I/usr/local/llvm17/include
-#cgo linux        LDFLAGS: -L/usr/lib/llvm-17/lib -lclang
-#cgo darwin,amd64 LDFLAGS: -L/usr/local/opt/llvm@17/lib -lclang
-#cgo darwin,arm64 LDFLAGS: -L/opt/homebrew/opt/llvm@17/lib -lclang
-#cgo freebsd      LDFLAGS: -L/usr/local/llvm17/lib -lclang
-*/
-import "C"
@@ -19,6 +19,7 @@ type Config struct {
 	Options        *Options
 	Target         *TargetSpec
 	GoMinorVersion int
+	ClangHeaders   string // Clang built-in header include path
 	TestConfig     TestConfig
 }

@@ -258,39 +259,24 @@ func (c *Config) DefaultBinaryExtension() string {

 // CFlags returns the flags to pass to the C compiler. This is necessary for CGo
 // preprocessing.
-func (c *Config) CFlags(libclang bool) []string {
+func (c *Config) CFlags() []string {
 	var cflags []string
 	for _, flag := range c.Target.CFlags {
 		cflags = append(cflags, strings.ReplaceAll(flag, "{root}", goenv.Get("TINYGOROOT")))
 	}
-	resourceDir := goenv.ClangResourceDir(libclang)
-	if resourceDir != "" {
-		// The resource directory contains the built-in clang headers like
-		// stdbool.h, stdint.h, float.h, etc.
-		// It is left empty if we're using an external compiler (that already
-		// knows these headers).
-		cflags = append(cflags,
-			"-resource-dir="+resourceDir,
-		)
-		if strings.HasPrefix(c.Triple(), "xtensa") {
-			// workaround needed in LLVM 16, see: https://github.com/espressif/llvm-project/issues/83
-			cflags = append(cflags, "-isystem", filepath.Join(resourceDir, "include"))
-		}
-	}
 	switch c.Target.Libc {
 	case "darwin-libSystem":
 		root := goenv.Get("TINYGOROOT")
 		cflags = append(cflags,
-			"-nostdlibinc",
-			"-isystem", filepath.Join(root, "lib/macos-minimal-sdk/src/usr/include"),
+			"--sysroot="+filepath.Join(root, "lib/macos-minimal-sdk/src"),
 		)
 	case "picolibc":
 		root := goenv.Get("TINYGOROOT")
 		picolibcDir := filepath.Join(root, "lib", "picolibc", "newlib", "libc")
 		path, _ := c.LibcPath("picolibc")
 		cflags = append(cflags,
-			"-nostdlibinc",
-			"-isystem", filepath.Join(path, "include"),
+			"--sysroot="+path,
+			"-isystem", filepath.Join(path, "include"), // necessary for Xtensa
 			"-isystem", filepath.Join(picolibcDir, "include"),
 			"-isystem", filepath.Join(picolibcDir, "tinystdio"),
 		)
@@ -311,8 +297,7 @@ func (c *Config) CFlags(libclang bool) []string {
 		root := goenv.Get("TINYGOROOT")
 		path, _ := c.LibcPath("mingw-w64")
 		cflags = append(cflags,
-			"-nostdlibinc",
-			"-isystem", filepath.Join(path, "include"),
+			"--sysroot="+path,
 			"-isystem", filepath.Join(root, "lib", "mingw-w64", "mingw-w64-headers", "crt"),
 			"-isystem", filepath.Join(root, "lib", "mingw-w64", "mingw-w64-headers", "defaults", "include"),
 			"-D_UCRT",
@@ -246,43 +246,6 @@ func LoadTarget(options *Options) (*TargetSpec, error) {
 	return spec, nil
 }

-// GetTargetSpecs retrieves target specifications from the TINYGOROOT targets
-// directory.  Only valid target JSON files are considered, and the function
-// returns a map of target names to their respective TargetSpec.
-func GetTargetSpecs() (map[string]*TargetSpec, error) {
-	dir := filepath.Join(goenv.Get("TINYGOROOT"), "targets")
-	entries, err := os.ReadDir(dir)
-	if err != nil {
-		return nil, fmt.Errorf("could not list targets: %w", err)
-	}
-
-	maps := map[string]*TargetSpec{}
-	for _, entry := range entries {
-		entryInfo, err := entry.Info()
-		if err != nil {
-			return nil, fmt.Errorf("could not get entry info: %w", err)
-		}
-		if !entryInfo.Mode().IsRegular() || !strings.HasSuffix(entry.Name(), ".json") {
-			// Only inspect JSON files.
-			continue
-		}
-		path := filepath.Join(dir, entry.Name())
-		spec, err := LoadTarget(&Options{Target: path})
-		if err != nil {
-			return nil, fmt.Errorf("could not list target: %w", err)
-		}
-		if spec.FlashMethod == "" && spec.FlashCommand == "" && spec.Emulator == "" {
-			// This doesn't look like a regular target file, but rather like
-			// a parent target (such as targets/cortex-m.json).
-			continue
-		}
-		name := entry.Name()
-		name = name[:len(name)-5]
-		maps[name] = spec
-	}
-	return maps, nil
-}
-
 func defaultTarget(goos, goarch, triple string) (*TargetSpec, error) {
 	// No target spec available. Use the default one, useful on most systems
 	// with a regular OS.
@@ -381,12 +344,12 @@ func defaultTarget(goos, goarch, triple string) (*TargetSpec, error) {
 		spec.Linker = "wasm-ld"
 		spec.RTLib = "compiler-rt"
 		spec.Libc = "wasi-libc"
-		spec.DefaultStackSize = 1024 * 64 // 64kB
+		spec.DefaultStackSize = 1024 * 32 // 32kB
 		spec.LDFlags = append(spec.LDFlags,
 			"--stack-first",
 			"--no-demangle",
 		)
-		spec.Emulator = "wasmtime --dir={tmpDir}::/tmp {}"
+		spec.Emulator = "wasmtime --mapdir=/tmp::{tmpDir} {}"
 		spec.ExtraFiles = append(spec.ExtraFiles,
 			"src/runtime/asm_tinygowasm.S",
 			"src/internal/task/task_asyncify_wasm.S",
@@ -243,7 +243,7 @@ func testCompilePackage(t *testing.T, options *compileopts.Options, file string)
 	defer machine.Dispose()

 	// Load entire program AST into memory.
-	lprogram, err := loader.Load(config, "./testdata/"+file, types.Config{
+	lprogram, err := loader.Load(config, "./testdata/"+file, config.ClangHeaders, types.Config{
 		Sizes: Sizes(machine),
 	})
 	if err != nil {
@@ -21,7 +21,7 @@ entry:
 ; Function Attrs: nounwind
 define hidden void @main.regularFunctionGoroutine(ptr %context) unnamed_addr #2 {
 entry:
-  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.regularFunction$gowrapper" to i32), ptr nonnull inttoptr (i32 5 to ptr), i32 65536, ptr undef) #9
+  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.regularFunction$gowrapper" to i32), ptr nonnull inttoptr (i32 5 to ptr), i32 32768, ptr undef) #9
  ret void
 }

@@ -43,7 +43,7 @@ declare void @"internal/task.start"(i32, ptr, i32, ptr) #1
 ; Function Attrs: nounwind
 define hidden void @main.inlineFunctionGoroutine(ptr %context) unnamed_addr #2 {
 entry:
-  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.inlineFunctionGoroutine$1$gowrapper" to i32), ptr nonnull inttoptr (i32 5 to ptr), i32 65536, ptr undef) #9
+  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.inlineFunctionGoroutine$1$gowrapper" to i32), ptr nonnull inttoptr (i32 5 to ptr), i32 32768, ptr undef) #9
  ret void
 }

@@ -76,7 +76,7 @@ entry:
  store i32 5, ptr %0, align 4
  %1 = getelementptr inbounds { i32, ptr }, ptr %0, i32 0, i32 1
  store ptr %n, ptr %1, align 4
-  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.closureFunctionGoroutine$1$gowrapper" to i32), ptr nonnull %0, i32 65536, ptr undef) #9
+  call void @"internal/task.start"(i32 ptrtoint (ptr @"main.closureFunctionGoroutine$1$gowrapper" to i32), ptr nonnull %0, i32 32768, ptr undef) #9
  %2 = load i32, ptr %n, align 4
  call void @runtime.printint32(i32 %2, ptr undef) #9
  ret void
@@ -113,7 +113,7 @@ entry:
  store ptr %fn.context, ptr %1, align 4
  %2 = getelementptr inbounds { i32, ptr, ptr }, ptr %0, i32 0, i32 2
  store ptr %fn.funcptr, ptr %2, align 4
-  call void @"internal/task.start"(i32 ptrtoint (ptr @main.funcGoroutine.gowrapper to i32), ptr nonnull %0, i32 65536, ptr undef) #9
+  call void @"internal/task.start"(i32 ptrtoint (ptr @main.funcGoroutine.gowrapper to i32), ptr nonnull %0, i32 32768, ptr undef) #9
  ret void
 }

@@ -167,7 +167,7 @@ entry:
  store i32 4, ptr %.repack1, align 4
  %2 = getelementptr inbounds { ptr, %runtime._string, ptr }, ptr %0, i32 0, i32 2
  store ptr %itf.typecode, ptr %2, align 4
-  call void @"internal/task.start"(i32 ptrtoint (ptr @"interface:{Print:func:{basic:string}{}}.Print$invoke$gowrapper" to i32), ptr nonnull %0, i32 65536, ptr undef) #9
+  call void @"internal/task.start"(i32 ptrtoint (ptr @"interface:{Print:func:{basic:string}{}}.Print$invoke$gowrapper" to i32), ptr nonnull %0, i32 32768, ptr undef) #9
  ret void
 }

@@ -1,60 +0,0 @@
-{
-  "nodes": {
-    "flake-utils": {
-      "inputs": {
-        "systems": "systems"
-      },
-      "locked": {
-        "lastModified": 1694529238,
-        "narHash": "sha256-zsNZZGTGnMOf9YpHKJqMSsa0dXbfmxeoJ7xHlrt+xmY=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "ff7b65b44d01cf9ba6a71320833626af21126384",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1696983906,
-        "narHash": "sha256-L7GyeErguS7Pg4h8nK0wGlcUTbfUMDu+HMf1UcyP72k=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "bd1cde45c77891214131cbbea5b1203e485a9d51",
-        "type": "github"
-      },
-      "original": {
-        "id": "nixpkgs",
-        "ref": "nixos-23.05",
-        "type": "indirect"
-      }
-    },
-    "root": {
-      "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs"
-      }
-    },
-    "systems": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
-    }
-  },
-  "root": "root",
-  "version": 7
-}
@@ -1,85 +0,0 @@
-# A Nix flake file, mainly intended for developing TinyGo.
-# You can download Nix here, for use on your Linux or macOS system:
-#   https://nixos.org/download.html
-# After you have installed Nix, you can enter the development environment as
-# follows:
-#
-#   nix develop
-#
-# This drops you into a bash shell, where you can install TinyGo simply using
-# the following command:
-#
-#   go install
-#
-# That's all! Assuming you've set up your $PATH correctly, you can now use the
-# tinygo command as usual:
-#
-#   tinygo version
-#
-# But you'll need a bit more to make TinyGo actually able to compile code:
-#
-#   make llvm-source                        # fetch compiler-rt
-#   git submodule update --init --recursive # fetch lots of other libraries and SVD files
-#   make gen-device -j4                     # build src/device/*/*.go files
-#   make wasi-libc                          # build support for wasi/wasm
-#
-# With this, you should have an environment that can compile anything - except
-# for the Xtensa architecture (ESP8266/ESP32) because support for that lives in
-# a separate LLVM fork.
-#
-# You can also do many other things from this environment. Building and flashing
-# should work as you're used to: it's not a VM or container so there are no
-# access restrictions and you're running in the same host environment - just
-# with a slightly different set of tools available.
-{
-  inputs = {
-    # Use a recent stable release, but fix the version to make it reproducible.
-    # This version should be updated from time to time.
-    nixpkgs.url = "nixpkgs/nixos-23.05";
-    flake-utils.url = "github:numtide/flake-utils";
-  };
-  outputs = { self, nixpkgs, flake-utils }:
-    flake-utils.lib.eachDefaultSystem (system:
-      let
-        pkgs = nixpkgs.legacyPackages.${system};
-      in
-      with pkgs;
-      {
-        devShells.default = mkShell {
-          buildInputs = [
-            # These dependencies are required for building tinygo (go install).
-            go
-            llvmPackages_16.llvm
-            llvmPackages_16.libclang
-            # Additional dependencies needed at runtime, for building and/or
-            # flashing.
-            llvmPackages_16.lld
-            avrdude
-            binaryen
-            # Additional dependencies needed for on-chip debugging.
-            # These tools are rather big (especially GDB) and not frequently
-            # used, so are commented out. On-chip debugging is still possible if
-            # these tools are available in the host environment.
-            #gdb
-            #openocd
-          ];
-          shellHook= ''
-            # Configure CLANG, LLVM_AR, and LLVM_NM for `make wasi-libc`.
-            # Without setting these explicitly, Homebrew versions might be used
-            # or the default `ar` and `nm` tools might be used (which don't
-            # support wasi).
-            export CLANG="clang-16 -resource-dir ${llvmPackages_16.clang.cc.lib}/lib/clang/16"
-            export LLVM_AR=llvm-ar
-            export LLVM_NM=llvm-nm
-
-            # Make `make smoketest` work (the default is `md5`, while Nix only
-            # has `md5sum`).
-            export MD5SUM=md5sum
-
-            # Ugly hack to make the Clang resources directory available.
-            export GOFLAGS="\"-ldflags=-X github.com/tinygo-org/tinygo/goenv.clangResourceDir=${llvmPackages_16.clang.cc.lib}/lib/clang/16"\"
-          '';
-        };
-      }
-    );
-}
@@ -18,7 +18,7 @@ require (
 	golang.org/x/sys v0.11.0
 	golang.org/x/tools v0.12.0
 	gopkg.in/yaml.v2 v2.4.0
-	tinygo.org/x/go-llvm v0.0.0-20231014233752-75a8a9fe6f74
+	tinygo.org/x/go-llvm v0.0.0-20230920233244-32ed56c6be9c
 )

 require (
@@ -65,5 +65,5 @@ gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
-tinygo.org/x/go-llvm v0.0.0-20231014233752-75a8a9fe6f74 h1:tW8XhLI9gUZLL+2pG0HYb5dc6bpMj1aqtESpizXPnMY=
-tinygo.org/x/go-llvm v0.0.0-20231014233752-75a8a9fe6f74/go.mod h1:GFbusT2VTA4I+l4j80b17KFK+6whv69Wtny5U+T8RR0=
+tinygo.org/x/go-llvm v0.0.0-20230920233244-32ed56c6be9c h1:rS8mAFqf0CfxPCbtfsI3bWL4jkb0TBYA1wx7tY1nu28=
+tinygo.org/x/go-llvm v0.0.0-20230920233244-32ed56c6be9c/go.mod h1:GFbusT2VTA4I+l4j80b17KFK+6whv69Wtny5U+T8RR0=
@@ -14,8 +14,6 @@ import (
 	"runtime"
 	"strings"
 	"sync"
-
-	"tinygo.org/x/go-llvm"
 )

 // Keys is a slice of all available environment variable keys.
@@ -35,20 +33,11 @@ func init() {
 	}
 }

-// Set to true if we're linking statically against LLVM.
-var hasBuiltinTools = false
-
 // TINYGOROOT is the path to the final location for checking tinygo files. If
 // unset (by a -X ldflag), then sourceDir() will fallback to the original build
 // directory.
 var TINYGOROOT string

-// If a particular Clang resource dir must always be used and TinyGo can't
-// figure out the directory using heuristics, this global can be set using a
-// linker flag.
-// This is needed for Nix.
-var clangResourceDir string
-
 // Variables read from a `go env` command invocation.
 var goEnvVars struct {
 	GOPATH    string
@@ -295,95 +284,3 @@ func isSourceDir(root string) bool {
 	_, err = os.Stat(filepath.Join(root, "src/device/arm/arm.go"))
 	return err == nil
 }
-
-// ClangResourceDir returns the clang resource dir if available. This is the
-// -resource-dir flag. If it isn't available, an empty string is returned and
-// -resource-dir should be left unset.
-// The libclang flag must be set if the resource dir is read for use by
-// libclang.
-// In that case, the resource dir is always returned (even when linking
-// dynamically against LLVM) because libclang always needs this directory.
-func ClangResourceDir(libclang bool) string {
-	if clangResourceDir != "" {
-		// The resource dir is forced to a particular value at build time.
-		// This is needed on Nix for example, where Clang and libclang don't
-		// know their own resource dir.
-		// Also see:
-		// https://discourse.nixos.org/t/why-is-the-clang-resource-dir-split-in-a-separate-package/34114
-		return clangResourceDir
-	}
-
-	if !hasBuiltinTools && !libclang {
-		// Using external tools, so the resource dir doesn't need to be
-		// specified. Clang knows where to find it.
-		return ""
-	}
-
-	// Check whether we're running from a TinyGo release directory.
-	// This is the case for release binaries on GitHub.
-	root := Get("TINYGOROOT")
-	releaseHeaderDir := filepath.Join(root, "lib", "clang")
-	if _, err := os.Stat(releaseHeaderDir); !errors.Is(err, fs.ErrNotExist) {
-		return releaseHeaderDir
-	}
-
-	if hasBuiltinTools {
-		// We are statically linked to LLVM.
-		// Check whether we're running from the source directory.
-		// This typically happens when TinyGo was built using `make` as part of
-		// development.
-		llvmMajor := strings.Split(llvm.Version, ".")[0]
-		buildResourceDir := filepath.Join(root, "llvm-build", "lib", "clang", llvmMajor)
-		if _, err := os.Stat(buildResourceDir); !errors.Is(err, fs.ErrNotExist) {
-			return buildResourceDir
-		}
-	} else {
-		// We use external tools, either when installed using `go install` or
-		// when packaged in a Linux distribution (Linux distros typically prefer
-		// dynamic linking).
-		// Try to detect the system clang resources directory.
-		resourceDir := findSystemClangResources(root)
-		if resourceDir != "" {
-			return resourceDir
-		}
-	}
-
-	// Resource directory not found.
-	return ""
-}
-
-// Find the Clang resource dir on this particular system.
-// Return the empty string when they aren't found.
-func findSystemClangResources(TINYGOROOT string) string {
-	llvmMajor := strings.Split(llvm.Version, ".")[0]
-
-	switch runtime.GOOS {
-	case "linux", "android":
-		// Header files are typically stored in /usr/lib/clang/<version>/include.
-		// Tested on Fedora 39, Debian 12, and Arch Linux.
-		path := filepath.Join("/usr/lib/clang", llvmMajor)
-		_, err := os.Stat(filepath.Join(path, "include", "stdint.h"))
-		if err == nil {
-			return path
-		}
-	case "darwin":
-		// This assumes a Homebrew installation, like in builder/commands.go.
-		var prefix string
-		switch runtime.GOARCH {
-		case "amd64":
-			prefix = "/usr/local/opt/llvm@" + llvmMajor
-		case "arm64":
-			prefix = "/opt/homebrew/opt/llvm@" + llvmMajor
-		default:
-			return "" // very unlikely for now
-		}
-		path := fmt.Sprintf("%s/lib/clang/%s", prefix, llvmMajor)
-		_, err := os.Stat(path + "/include/stdint.h")
-		if err == nil {
-			return path
-		}
-	}
-
-	// Could not find it.
-	return ""
-}
@@ -1,7 +0,0 @@
-//go:build byollvm
-
-package goenv
-
-func init() {
-	hasBuiltinTools = true
-}
@@ -9,7 +9,7 @@ import (

 // Version of TinyGo.
 // Update this value before release of new version of software.
-const version = "0.31.0-dev"
+const Version = "0.30.0"

 var (
 	// This variable is set at build time using -ldflags parameters.
@@ -17,16 +17,6 @@ var (
 	GitSha1 string
 )

-// Return TinyGo version, either in the form 0.30.0 or as a development version
-// (like 0.30.0-dev-abcd012).
-func Version() string {
-	v := version
-	if strings.HasSuffix(version, "-dev") && GitSha1 != "" {
-		v += "-" + GitSha1
-	}
-	return v
-}
-
 // GetGorootVersion returns the major and minor version for a given GOROOT path.
 // If the goroot cannot be determined, (0, 0) is returned.
 func GetGorootVersion() (major, minor int, err error) {
@@ -1,4 +1,4 @@
 #!/bin/bash
 # Docker hub does a recursive clone, then checks the branch out,
 # so when a PR adds a submodule (or updates it), it fails.
-git submodule update --init --recursive
+git submodule update --init
@@ -18,6 +18,7 @@ import (
 	"errors"
 	"io"
 	"io/fs"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -156,7 +157,7 @@ func listGorootMergeLinks(goroot, tinygoroot string, overrides map[string]bool)

 		// Add files from TinyGo.
 		tinygoDir := filepath.Join(tinygoSrc, dir)
-		tinygoEntries, err := os.ReadDir(tinygoDir)
+		tinygoEntries, err := ioutil.ReadDir(tinygoDir)
 		if err != nil {
 			return nil, err
 		}
@@ -176,7 +177,7 @@ func listGorootMergeLinks(goroot, tinygoroot string, overrides map[string]bool)
 		// Add all directories from $GOROOT that are not part of the TinyGo
 		// overrides.
 		goDir := filepath.Join(goSrc, dir)
-		goEntries, err := os.ReadDir(goDir)
+		goEntries, err := ioutil.ReadDir(goDir)
 		if err != nil {
 			return nil, err
 		}
@@ -29,10 +29,11 @@ import (

 // Program holds all packages and some metadata about the program as a whole.
 type Program struct {
-	config      *compileopts.Config
-	typeChecker types.Config
-	goroot      string // synthetic GOROOT
-	workingDir  string
+	config       *compileopts.Config
+	clangHeaders string
+	typeChecker  types.Config
+	goroot       string // synthetic GOROOT
+	workingDir   string

 	Packages map[string]*Package
 	sorted   []*Package
@@ -102,7 +103,7 @@ type EmbedFile struct {
 // Load loads the given package with all dependencies (including the runtime
 // package). Call .Parse() afterwards to parse all Go files (including CGo
 // processing, if necessary).
-func Load(config *compileopts.Config, inputPkg string, typeChecker types.Config) (*Program, error) {
+func Load(config *compileopts.Config, inputPkg string, clangHeaders string, typeChecker types.Config) (*Program, error) {
 	goroot, err := GetCachedGoroot(config)
 	if err != nil {
 		return nil, err
@@ -117,12 +118,13 @@ func Load(config *compileopts.Config, inputPkg string, typeChecker types.Config)
 		}
 	}
 	p := &Program{
-		config:      config,
-		typeChecker: typeChecker,
-		goroot:      goroot,
-		workingDir:  wd,
-		Packages:    make(map[string]*Package),
-		fset:        token.NewFileSet(),
+		config:       config,
+		clangHeaders: clangHeaders,
+		typeChecker:  typeChecker,
+		goroot:       goroot,
+		workingDir:   wd,
+		Packages:     make(map[string]*Package),
+		fset:         token.NewFileSet(),
 	}

 	// List the dependencies of this package, in raw JSON format.
@@ -436,9 +438,9 @@ func (p *Package) parseFiles() ([]*ast.File, error) {
 	// to call cgo.Process in that case as it will only cause issues.
 	if len(p.CgoFiles) != 0 && len(files) != 0 {
 		var initialCFlags []string
-		initialCFlags = append(initialCFlags, p.program.config.CFlags(true)...)
+		initialCFlags = append(initialCFlags, p.program.config.CFlags()...)
 		initialCFlags = append(initialCFlags, "-I"+p.Dir)
-		generated, headerCode, cflags, ldflags, accessedFiles, errs := cgo.Process(files, p.program.workingDir, p.ImportPath, p.program.fset, initialCFlags)
+		generated, headerCode, cflags, ldflags, accessedFiles, errs := cgo.Process(files, p.program.workingDir, p.ImportPath, p.program.fset, initialCFlags, p.program.clangHeaders)
 		p.CFlags = append(initialCFlags, cflags...)
 		p.CGoHeaders = headerCode
 		for path, hash := range accessedFiles {
@@ -11,6 +11,7 @@ import (
 	"go/scanner"
 	"go/types"
 	"io"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -797,7 +798,7 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 			needsEnvInVars = true
 		}
 	}
-	var args, emuArgs, env []string
+	var args, env []string
 	var extraCmdEnv []string
 	if needsEnvInVars {
 		runtimeGlobals := make(map[string]string)
@@ -820,14 +821,13 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 	} else if config.EmulatorName() == "wasmtime" {
 		// Wasmtime needs some special flags to pass environment variables
 		// and allow reading from the current directory.
-		emuArgs = append(emuArgs, "--dir=.")
+		args = append(args, "--dir=.")
 		for _, v := range environmentVars {
-			emuArgs = append(emuArgs, "--env", v)
+			args = append(args, "--env", v)
 		}
 		if len(cmdArgs) != 0 {
-			// Use of '--' argument no longer necessary as of Wasmtime v14:
-			// https://github.com/bytecodealliance/wasmtime/pull/6946
-			// args = append(args, "--")
+			// mark end of wasmtime arguments and start of program ones: --
+			args = append(args, "--")
 			args = append(args, cmdArgs...)
 		}

@@ -877,7 +877,7 @@ func buildAndRun(pkgName string, config *compileopts.Config, stdout io.Writer, c
 			return result, err
 		}
 		name = emulator[0]
-		emuArgs = append(emuArgs, emulator[1:]...)
+		emuArgs := append([]string(nil), emulator[1:]...)
 		args = append(emuArgs, args...)
 	}
 	var cmd *exec.Cmd
@@ -1212,10 +1212,15 @@ func getBMPPorts() (gdbPort, uartPort string, err error) {
 }

 func usage(command string) {
+	version := goenv.Version
+	if strings.HasSuffix(version, "-dev") && goenv.GitSha1 != "" {
+		version += "-" + goenv.GitSha1
+	}
+
 	switch command {
 	default:
 		fmt.Fprintln(os.Stderr, "TinyGo is a Go compiler for small places.")
-		fmt.Fprintln(os.Stderr, "version:", goenv.Version())
+		fmt.Fprintln(os.Stderr, "version:", version)
 		fmt.Fprintf(os.Stderr, "usage: %s <command> [arguments]\n", os.Args[0])
 		fmt.Fprintln(os.Stderr, "\ncommands:")
 		fmt.Fprintln(os.Stderr, "  build:   compile packages and dependencies")
@@ -1437,7 +1442,6 @@ func main() {
 	llvmFeatures := flag.String("llvm-features", "", "comma separated LLVM features to enable")
 	cpuprofile := flag.String("cpuprofile", "", "cpuprofile output")
 	monitor := flag.Bool("monitor", false, "enable serial monitor")
-	info := flag.Bool("info", false, "print information")
 	baudrate := flag.Int("baudrate", 115200, "baudrate of serial monitor")

 	// Internal flags, that are only intended for TinyGo development.
@@ -1733,29 +1737,35 @@ func main() {
 			os.Exit(1)
 		}
 	case "monitor":
-		if *info {
-			serialPortInfo, err := ListSerialPorts()
-			handleCompilerError(err)
-			for _, s := range serialPortInfo {
-				fmt.Printf("%s %4s %4s %s\n", s.Name, s.VID, s.PID, s.Target)
-			}
-		} else {
-			err := Monitor("", *port, options)
-			handleCompilerError(err)
-		}
+		err := Monitor("", *port, options)
+		handleCompilerError(err)
 	case "targets":
-		specs, err := compileopts.GetTargetSpecs()
+		dir := filepath.Join(goenv.Get("TINYGOROOT"), "targets")
+		entries, err := ioutil.ReadDir(dir)
 		if err != nil {
 			fmt.Fprintln(os.Stderr, "could not list targets:", err)
 			os.Exit(1)
 			return
 		}
-		names := []string{}
-		for key := range specs {
-			names = append(names, key)
-		}
-		sort.Strings(names)
-		for _, name := range names {
+		for _, entry := range entries {
+			if !entry.Mode().IsRegular() || !strings.HasSuffix(entry.Name(), ".json") {
+				// Only inspect JSON files.
+				continue
+			}
+			path := filepath.Join(dir, entry.Name())
+			spec, err := compileopts.LoadTarget(&compileopts.Options{Target: path})
+			if err != nil {
+				fmt.Fprintln(os.Stderr, "could not list target:", err)
+				os.Exit(1)
+				return
+			}
+			if spec.FlashMethod == "" && spec.FlashCommand == "" && spec.Emulator == "" {
+				// This doesn't look like a regular target file, but rather like
+				// a parent target (such as targets/cortex-m.json).
+				continue
+			}
+			name := entry.Name()
+			name = name[:len(name)-5]
 			fmt.Println(name)
 		}
 	case "info":
@@ -1864,7 +1874,11 @@ func main() {
 		if s, err := goenv.GorootVersionString(); err == nil {
 			goversion = s
 		}
-		fmt.Printf("tinygo version %s %s/%s (using go version %s and LLVM version %s)\n", goenv.Version(), runtime.GOOS, runtime.GOARCH, goversion, llvm.Version)
+		version := goenv.Version
+		if strings.HasSuffix(goenv.Version, "-dev") && goenv.GitSha1 != "" {
+			version += "-" + goenv.GitSha1
+		}
+		fmt.Printf("tinygo version %s %s/%s (using go version %s and LLVM version %s)\n", version, runtime.GOOS, runtime.GOARCH, goversion, llvm.Version)
 	case "env":
 		if flag.NArg() == 0 {
 			// Show all environment variables.
@@ -13,15 +13,12 @@ import (
 	"os/signal"
 	"regexp"
 	"strconv"
-	"strings"
 	"time"

 	"github.com/mattn/go-tty"
 	"github.com/tinygo-org/tinygo/builder"
 	"github.com/tinygo-org/tinygo/compileopts"
-
 	"go.bug.st/serial"
-	"go.bug.st/serial/enumerator"
 )

 // Monitor connects to the given port and reads/writes the serial port.
@@ -131,59 +128,6 @@ func Monitor(executable, port string, options *compileopts.Options) error {
 	return <-errCh
 }

-// SerialPortInfo is a structure that holds information about the port and its
-// associated TargetSpec.
-type SerialPortInfo struct {
-	Name   string
-	IsUSB  bool
-	VID    string
-	PID    string
-	Target string
-	Spec   *compileopts.TargetSpec
-}
-
-// ListSerialPort returns serial port information and any detected TinyGo
-// target.
-func ListSerialPorts() ([]SerialPortInfo, error) {
-	maps, err := compileopts.GetTargetSpecs()
-	if err != nil {
-		return nil, err
-	}
-
-	portsList, err := enumerator.GetDetailedPortsList()
-	if err != nil {
-		return nil, err
-	}
-
-	serialPortInfo := []SerialPortInfo{}
-	for _, p := range portsList {
-		info := SerialPortInfo{
-			Name:  p.Name,
-			IsUSB: p.IsUSB,
-			VID:   p.VID,
-			PID:   p.PID,
-		}
-		vid := strings.ToLower(p.VID)
-		pid := strings.ToLower(p.PID)
-		for k, v := range maps {
-			usbInterfaces := v.SerialPort
-			for _, s := range usbInterfaces {
-				parts := strings.Split(s, ":")
-				if len(parts) != 2 {
-					continue
-				}
-				if vid == strings.ToLower(parts[0]) && pid == strings.ToLower(parts[1]) {
-					info.Target = k
-					info.Spec = v
-				}
-			}
-		}
-		serialPortInfo = append(serialPortInfo, info)
-	}
-
-	return serialPortInfo, nil
-}
-
 var addressMatch = regexp.MustCompile(`^panic: runtime error at 0x([0-9a-f]+): `)

 // Extract the address from the "panic: runtime error at" message.
@@ -1,21 +0,0 @@
-package main
-
-import (
-	"encoding/hex"
-	"machine"
-	"time"
-)
-
-func main() {
-	time.Sleep(2 * time.Second)
-
-	// For efficiency, it's best to get the device ID once and cache it
-	// (e.g. on RP2040 XIP flash and interrupts disabled for period of
-	// retrieving the hardware ID from ROM chip)
-	id := machine.DeviceID()
-
-	for {
-		println("Device ID:", hex.EncodeToString(id))
-		time.Sleep(1 * time.Second)
-	}
-}
@@ -24,9 +24,7 @@ func main() {

 	// Schedule and enable recurring interrupt.
 	// The callback function is executed in the context of an interrupt handler,
-	// so regular restrictions for this sort of code apply: no blocking, no memory allocation, etc.
-	// Please check the online documentation for the details about interrupts:
-	// https://tinygo.org/docs/concepts/compiler-internals/interrupts/
+	// so regular restructions for this sort of code apply: no blocking, no memory allocation, etc.
 	delay := time.Minute + 12*time.Second
 	machine.RTC.SetInterrupt(uint32(delay.Seconds()), true, func() { println("Peekaboo!") })

@@ -1,17 +0,0 @@
-//go:build rp2040 || nrf || sam
-
-package machine
-
-// DeviceID returns an identifier that is unique within
-// a particular chipset.
-//
-// The identity is one burnt into the MCU itself, or the
-// flash chip at time of manufacture.
-//
-// It's possible that two different vendors may allocate
-// the same DeviceID, so callers should take this into
-// account if needing to generate a globally unique id.
-//
-// The length of the hardware ID is vendor-specific, but
-// 8 bytes (64 bits) and 16 bytes (128 bits) are common.
-var _ = (func() []byte)(DeviceID)
@@ -1,4 +1,4 @@
-//go:build atmega || nrf || sam || stm32 || fe310 || k210 || rp2040 || mimxrt1062
+//go:build atmega || nrf || sam || stm32 || fe310 || k210 || rp2040

 package machine

@@ -6,17 +6,6 @@ import (
 	"errors"
 )

-// If you are getting a compile error on this line please check to see you've
-// correctly implemented the methods on the I2C type. They must match
-// the i2cController interface method signatures type to type perfectly.
-// If not implementing the I2C type please remove your target from the build tags
-// at the top of this file.
-var _ interface { // 2
-	Configure(config I2CConfig) error
-	Tx(addr uint16, w, r []byte) error
-	SetBaudRate(br uint32) error
-} = (*I2C)(nil)
-
 // TWI_FREQ is the I2C bus speed. Normally either 100 kHz, or 400 kHz for high-speed bus.
 //
 // Deprecated: use 100 * machine.KHz or 400 * machine.KHz instead.
@@ -36,7 +25,6 @@ var (
 	errI2CBusError           = errors.New("I2C bus error")
 	errI2COverflow           = errors.New("I2C receive buffer overflow")
 	errI2COverread           = errors.New("I2C transmit buffer overflow")
-	errI2CNotImplemented     = errors.New("I2C operation not yet implemented")
 )

 // I2CTargetEvent reflects events on the I2C bus
@@ -31,11 +31,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	// Activate internal pullups for twi.
 	avr.PORTC.SetBits((avr.DIDR0_ADC4D | avr.DIDR0_ADC5D))

-	return i2c.SetBaudRate(config.Frequency)
-}
-
-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
 	// Initialize twi prescaler and bit rate.
 	avr.TWSR.SetBits((avr.TWSR_TWPS0 | avr.TWSR_TWPS1))

@@ -43,7 +38,7 @@ func (i2c *I2C) SetBaudRate(br uint32) error {
 	// SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR))
 	// NOTE: TWBR should be 10 or higher for controller mode.
 	// It is 72 for a 16mhz board with 100kHz TWI
-	avr.TWBR.Set(uint8(((CPUFrequency() / br) - 16) / 2))
+	avr.TWBR.Set(uint8(((CPUFrequency() / config.Frequency) - 16) / 2))

 	// Enable twi module.
 	avr.TWCR.Set(avr.TWCR_TWEN)
@@ -1,31 +0,0 @@
-//go:build sam
-
-package machine
-
-import (
-	"runtime/volatile"
-	"unsafe"
-)
-
-var deviceID [16]byte
-
-// DeviceID returns an identifier that is unique within
-// a particular chipset.
-//
-// The identity is one burnt into the MCU itself, or the
-// flash chip at time of manufacture.
-//
-// It's possible that two different vendors may allocate
-// the same DeviceID, so callers should take this into
-// account if needing to generate a globally unique id.
-//
-// The length of the hardware ID is vendor-specific, but
-// 8 bytes (64 bits) and 16 bytes (128 bits) are common.
-func DeviceID() []byte {
-	for i := 0; i < len(deviceID); i++ {
-		word := (*volatile.Register32)(unsafe.Pointer(deviceIDAddr[i/4])).Get()
-		deviceID[i] = byte(word >> ((i % 4) * 8))
-	}
-
-	return deviceID[:]
-}
@@ -18,9 +18,6 @@ import (

 const deviceName = sam.Device

-// DS40001882F, Section 10.3.3: Serial Number
-var deviceIDAddr = []uintptr{0x0080A00C, 0x0080A040, 0x0080A044, 0x0080A048}
-
 const (
 	PinAnalog    PinMode = 1
 	PinSERCOM    PinMode = 2
@@ -735,13 +732,12 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
+// SetBaudRate sets the communication speed for the I2C.
+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 := CPUFrequency()/(2*br) - 5 - (((CPUFrequency() / 1000000) * riseTimeNanoseconds) / (2 * 1000))
 	i2c.Bus.BAUD.Set(baud)
-	return nil
 }

 // Tx does a single I2C transaction at the specified address.
@@ -18,9 +18,6 @@ import (

 const deviceName = sam.Device

-// DS60001507, Section 9.6: Serial Number
-var deviceIDAddr = []uintptr{0x008061FC, 0x00806010, 0x00806014, 0x00806018}
-
 func CPUFrequency() uint32 {
 	return 120000000
 }
@@ -683,56 +680,6 @@ func (p Pin) getPinGrouping() (uint8, uint8) {
 	return group, pin_in_group
 }

-// Static DMA channel allocation.
-// If there are a lot of DMA using peripherals, we might need to switch to
-// dynamic allocation instead.
-const (
-	dmaChannelSERCOM0 = iota
-	dmaChannelSERCOM1
-	dmaChannelSERCOM2
-	dmaChannelSERCOM3
-	dmaChannelSERCOM4
-	dmaChannelSERCOM5
-	dmaChannelSERCOM6
-	dmaChannelSERCOM7
-	dmaNumChannels
-)
-
-// DMA descriptor structure. This structure is defined by the hardware, and is
-// described by "22.9 Register Summary - SRAM" in the datasheet.
-type dmaDescriptor struct {
-	btctrl   uint16
-	btcnt    uint16
-	srcaddr  unsafe.Pointer
-	dstaddr  unsafe.Pointer
-	descaddr unsafe.Pointer
-}
-
-//go:align 16
-var dmaDescriptorSection [dmaNumChannels]dmaDescriptor
-
-//go:align 16
-var dmaDescriptorWritebackSection [dmaNumChannels]dmaDescriptor
-
-// Enable and configure the DMAC peripheral if it hasn't been enabled already.
-func enableDMAC() {
-	if !sam.DMAC.CTRL.HasBits(sam.DMAC_CTRL_DMAENABLE) {
-		// Init DMAC.
-		// First configure the clocks, then configure the DMA descriptors. Those
-		// descriptors must live in SRAM and must be aligned on a 16-byte
-		// boundary.
-		// Some examples:
-		// http://www.lucadavidian.com/2018/03/08/wifi-controlled-neo-pixels-strips/
-		// https://svn.larosterna.com/oss/trunk/arduino/zerotimer/zerodma.cpp
-		sam.MCLK.AHBMASK.SetBits(sam.MCLK_AHBMASK_DMAC_)
-		sam.DMAC.BASEADDR.Set(uint32(uintptr(unsafe.Pointer(&dmaDescriptorSection))))
-		sam.DMAC.WRBADDR.Set(uint32(uintptr(unsafe.Pointer(&dmaDescriptorWritebackSection))))
-
-		// Enable peripheral with all priorities.
-		sam.DMAC.CTRL.SetBits(sam.DMAC_CTRL_DMAENABLE | sam.DMAC_CTRL_LVLEN0 | sam.DMAC_CTRL_LVLEN1 | sam.DMAC_CTRL_LVLEN2 | sam.DMAC_CTRL_LVLEN3)
-	}
-}
-
 // InitADC initializes the ADC.
 func InitADC() {
 	// ADC Bias Calibration
@@ -1281,13 +1228,12 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
+// SetBaudRate sets the communication speed for the I2C.
+func (i2c *I2C) SetBaudRate(br uint32) {
 	// Synchronous arithmetic baudrate, via Adafruit SAMD51 implementation:
 	// sercom->I2CM.BAUD.bit.BAUD = SERCOM_FREQ_REF / ( 2 * baudrate) - 1 ;
 	baud := SERCOM_FREQ_REF/(2*br) - 1
 	i2c.Bus.BAUD.Set(baud)
-	return nil
 }

 // Tx does a single I2C transaction at the specified address.
@@ -1702,101 +1648,6 @@ func (spi SPI) txrx(tx, rx []byte) {
 	rx[len(rx)-1] = byte(spi.Bus.DATA.Get())
 }

-// Channel to be used for SPI transfers.
-// These channels are currently statically allocated.
-func (spi SPI) dmaTxChannel() uint8 {
-	return dmaChannelSERCOM0 + spi.SERCOM
-}
-
-// IsAsync returns whether the SPI supports async operation (usually DMA).
-//
-// It returns true on the SAM D5x chips.
-func (spi SPI) IsAsync() bool {
-	return true
-}
-
-// Start a transfer in the background.
-//
-// After this, another StartTx() or Wait() must be called. The provided byte
-// slices (tx and rx) may only be accessed again after Wait() was called.
-func (s SPI) StartTx(tx, rx []byte) error {
-	// Check whether we support doing this transfer using DMA.
-	if len(rx) != 0 {
-		return s.Tx(tx, rx)
-	}
-	if len(tx) == 0 {
-		return nil // nothing to send/receive
-	}
-	if len(tx) != int(uint16(len(tx))) {
-		// The transfer size is a 16-bit field.
-		// TODO: chain multiple transfers in some way when encountering these
-		// large buffer sizes. They're not currently implemented because
-		// transferring 64kB of data is less commonly done.
-		return s.Tx(tx, rx)
-	}
-
-	// Enable DMAC (if not already enabled).
-	enableDMAC()
-
-	// Wait until a possible previous transfer has been completed.
-	s.Wait()
-
-	// Configure the DMA channel, if it hasn't been configured already.
-	dstaddr := unsafe.Pointer(&s.Bus.DATA.Reg)
-	if dmaDescriptorSection[s.dmaTxChannel()].dstaddr != dstaddr {
-		// Configure channel descriptor.
-		dmaDescriptorSection[s.dmaTxChannel()] = dmaDescriptor{
-			btctrl: (1 << 0) | // VALID: Descriptor Valid
-				(0 << 3) | // BLOCKACT=NOACT: Block Action
-				(1 << 10) | // SRCINC: Source Address Increment Enable
-				(0 << 11) | // DSTINC: Destination Address Increment Enable
-				(1 << 12) | // STEPSEL=SRC: Step Selection
-				(0 << 13), // STEPSIZE=X1: Address Increment Step Size
-			dstaddr: dstaddr,
-		}
-
-		// Reset channel.
-		sam.DMAC.CHANNEL[s.dmaTxChannel()].CHCTRLA.ClearBits(sam.DMAC_CHANNEL_CHCTRLA_ENABLE)
-		sam.DMAC.CHANNEL[s.dmaTxChannel()].CHCTRLA.SetBits(sam.DMAC_CHANNEL_CHCTRLA_SWRST)
-
-		// Configure channel.
-		sam.DMAC.CHANNEL[s.dmaTxChannel()].CHPRILVL.Set(0)
-		sam.DMAC.CHANNEL[s.dmaTxChannel()].CHCTRLA.Set((sam.DMAC_CHANNEL_CHCTRLA_TRIGACT_BURST << sam.DMAC_CHANNEL_CHCTRLA_TRIGACT_Pos) |
-			(s.triggerSource() << sam.DMAC_CHANNEL_CHCTRLA_TRIGSRC_Pos) |
-			(sam.DMAC_CHANNEL_CHCTRLA_BURSTLEN_SINGLE << sam.DMAC_CHANNEL_CHCTRLA_BURSTLEN_Pos))
-	}
-
-	// For some reason, you have to provide the address just past the end of the
-	// array instead of the address of the array.
-	descriptor := &dmaDescriptorSection[s.dmaTxChannel()]
-	descriptor.srcaddr = unsafe.Pointer(uintptr(unsafe.Pointer(&tx[0])) + uintptr(len(tx)))
-	descriptor.btcnt = uint16(len(tx)) // beat count
-
-	// Start the transfer.
-	sam.DMAC.CHANNEL[s.dmaTxChannel()].CHCTRLA.SetBits(sam.DMAC_CHANNEL_CHCTRLA_ENABLE)
-
-	return nil
-}
-
-// Wait until all active transactions (started by StartTx) have finished. The
-// buffers provided in StartTx will be available after this method returns.
-func (spi SPI) Wait() error {
-	// Wait until the previous SPI transfer completed.
-	// This is basically the same thing as in SPI.tx.
-
-	// TODO: maybe block (and sleep) until the transfer has completed?
-
-	for !spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_TXC) {
-	}
-
-	// read to clear RXC register
-	for spi.Bus.INTFLAG.HasBits(sam.SERCOM_SPIM_INTFLAG_RXC) {
-		spi.Bus.DATA.Get()
-	}
-
-	return nil
-}
-
 // The QSPI peripheral on ATSAMD51 is only available on the following pins
 const (
 	QSPI_SCK   = PB10
@@ -62,27 +62,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has three TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -62,27 +62,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0B
-	case sam.SERCOM4_SPIM:
-		return 0x0D
-	case sam.SERCOM5_SPIM:
-		return 0x0F
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -62,27 +62,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -76,31 +76,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	case sam.SERCOM6_SPIM:
-		return 0x10
-	case sam.SERCOM7_SPIM:
-		return 0x12
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -76,31 +76,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	case sam.SERCOM6_SPIM:
-		return 0x10
-	case sam.SERCOM7_SPIM:
-		return 0x12
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -62,27 +62,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -76,31 +76,6 @@ func setSERCOMClockGenerator(sercom uint8, gclk uint32) {
 	}
 }

-// DMA trigger source
-func (spi SPI) triggerSource() (tx uint32) {
-	// See TRIGSRC field of CHCTRLA register for description of these constants.
-	switch spi.Bus {
-	case sam.SERCOM0_SPIM:
-		return 0x05
-	case sam.SERCOM1_SPIM:
-		return 0x07
-	case sam.SERCOM2_SPIM:
-		return 0x09
-	case sam.SERCOM3_SPIM:
-		return 0x0A
-	case sam.SERCOM4_SPIM:
-		return 0x0C
-	case sam.SERCOM5_SPIM:
-		return 0x0E
-	case sam.SERCOM6_SPIM:
-		return 0x10
-	case sam.SERCOM7_SPIM:
-		return 0x12
-	default:
-		return 0 // should be unreachable
-	}
-}
-
 // This chip has five TCC peripherals, which have PWM as one feature.
 var (
 	TCC0 = (*TCC)(sam.TCC0)
@@ -229,10 +229,9 @@ type I2CConfig struct {
 	SDA       Pin
 }

-var i2cClockFrequency uint32 = 32000000
-
 // Configure is intended to setup the I2C interface.
 func (i2c *I2C) Configure(config I2CConfig) error {
+	var i2cClockFrequency uint32 = 32000000
 	if config.Frequency == 0 {
 		config.Frequency = 100 * KHz
 	}
@@ -242,17 +241,7 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 		config.SCL = I2C0_SCL_PIN
 	}

-	i2c.SetBaudRate(config.Frequency)
-
-	config.SDA.Configure(PinConfig{Mode: PinI2C})
-	config.SCL.Configure(PinConfig{Mode: PinI2C})
-
-	return nil
-}
-
-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	var prescaler = i2cClockFrequency/(5*br) - 1
+	var prescaler = i2cClockFrequency/(5*config.Frequency) - 1

 	// disable controller before setting the prescale registers
 	i2c.Bus.CTR.ClearBits(sifive.I2C_CTR_EN)
@@ -264,6 +253,9 @@ func (i2c *I2C) SetBaudRate(br uint32) error {
 	// enable controller
 	i2c.Bus.CTR.SetBits(sifive.I2C_CTR_EN)

+	config.SDA.Configure(PinConfig{Mode: PinI2C})
+	config.SCL.Configure(PinConfig{Mode: PinI2C})
+
 	return nil
 }

@@ -57,9 +57,8 @@ type SPIConfig struct {
 	Mode      uint8
 }

-func (spi SPI) Configure(config SPIConfig) error {
+func (spi SPI) Configure(config SPIConfig) {
 	spiConfigure(spi.Bus, config.SCK, config.SDO, config.SDI)
-	return nil
 }

 // Transfer writes/reads a single byte using the SPI interface.
@@ -108,12 +107,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the I2C frequency.
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	i2cSetBaudRate(i2c.Bus, br)
-	return nil
-}
-
 // Tx does a single I2C transaction at the specified address.
 func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
 	i2cTransfer(i2c.Bus, &w[0], len(w), &r[0], len(r))
@@ -124,9 +117,6 @@ func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
 //export __tinygo_i2c_configure
 func i2cConfigure(bus uint8, scl Pin, sda Pin)

-//export __tinygo_i2c_set_baud_rate
-func i2cSetBaudRate(bus uint8, br uint32)
-
 //export __tinygo_i2c_transfer
 func i2cTransfer(bus uint8, w *byte, wlen int, r *byte, rlen int) int

@@ -563,19 +563,7 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 		config.SCL.SetFPIOAFunction(FUNC_I2C2_SCLK)
 	}

-	i2c.SetBaudRate(config.Frequency)
-
-	i2c.Bus.INTR_MASK.Set(0)
-	i2c.Bus.DMA_CR.Set(0x03)
-	i2c.Bus.DMA_RDLR.Set(0)
-	i2c.Bus.DMA_TDLR.Set(0x4)
-
-	return nil
-}
-
-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	div := CPUFrequency() / br / 16
+	div := CPUFrequency() / config.Frequency / 16

 	// Disable controller before setting the prescale register.
 	i2c.Bus.ENABLE.Set(0)
@@ -586,6 +574,11 @@ func (i2c *I2C) SetBaudRate(br uint32) error {
 	i2c.Bus.SS_SCL_HCNT.Set(uint32(div))
 	i2c.Bus.SS_SCL_LCNT.Set(uint32(div))

+	i2c.Bus.INTR_MASK.Set(0)
+	i2c.Bus.DMA_CR.Set(0x03)
+	i2c.Bus.DMA_RDLR.Set(0)
+	i2c.Bus.DMA_TDLR.Set(0x4)
+
 	return nil
 }

@@ -6,6 +6,19 @@ package machine

 import (
 	"device/nxp"
+	"errors"
+)
+
+var (
+	errI2CWriteTimeout       = errors.New("I2C timeout during write")
+	errI2CReadTimeout        = errors.New("I2C timeout during read")
+	errI2CBusReadyTimeout    = errors.New("I2C timeout on bus ready")
+	errI2CSignalStartTimeout = errors.New("I2C timeout on signal start")
+	errI2CSignalReadTimeout  = errors.New("I2C timeout on signal read")
+	errI2CSignalStopTimeout  = errors.New("I2C timeout on signal stop")
+	errI2CAckExpected        = errors.New("I2C error: expected ACK not NACK")
+	errI2CBusError           = errors.New("I2C bus error")
+	errI2CNotConfigured      = errors.New("I2C interface is not yet configured")
 )

 // I2CConfig is used to store config info for I2C.
@@ -137,7 +150,7 @@ func (i2c *I2C) setPins(c I2CConfig) (sda, scl Pin) {
 }

 // Configure is intended to setup an I2C interface for transmit/receive.
-func (i2c *I2C) Configure(config I2CConfig) error {
+func (i2c *I2C) Configure(config I2CConfig) {
 	// init pins
 	sda, scl := i2c.setPins(config)

@@ -156,14 +169,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {

 	// reset clock and registers, and enable LPI2C module interface
 	i2c.reset(freq)
-
-	return nil
-}
-
-// SetBaudRate sets the communication speed for I2C.
-func (i2c I2C) SetBaudRate(br uint32) error {
-	// TODO: implement
-	return errI2CNotImplemented
 }

 func (i2c I2C) Tx(addr uint16, w, r []byte) error {
@@ -207,13 +212,13 @@ func (i2c I2C) Tx(addr uint16, w, r []byte) error {
 	return nil
 }

-// WriteRegisterEx transmits first the register and then the data to the
+// WriteRegister transmits first the register and then the data to the
 // peripheral device.
 //
 // Many I2C-compatible devices are organized in terms of registers. This method
 // is a shortcut to easily write to such registers. Also, it only works for
 // devices with 7-bit addresses, which is the vast majority.
-func (i2c I2C) WriteRegisterEx(address uint8, register uint8, data []byte) error {
+func (i2c I2C) WriteRegister(address uint8, register uint8, data []byte) error {
 	option := transferOption{
 		flags:          transferDefault,  // transfer options bit mask (0 = normal transfer)
 		peripheral:     uint16(address),  // 7-bit peripheral address
@@ -227,13 +232,13 @@ func (i2c I2C) WriteRegisterEx(address uint8, register uint8, data []byte) error
 	return nil
 }

-// ReadRegisterEx transmits the register, restarts the connection as a read
+// ReadRegister transmits the register, restarts the connection as a read
 // operation, and reads the response.
 //
 // Many I2C-compatible devices are organized in terms of registers. This method
 // is a shortcut to easily read such registers. Also, it only works for devices
 // with 7-bit addresses, which is the vast majority.
-func (i2c I2C) ReadRegisterEx(address uint8, register uint8, data []byte) error {
+func (i2c I2C) ReadRegister(address uint8, register uint8, data []byte) error {
 	option := transferOption{
 		flags:          transferDefault,  // transfer options bit mask (0 = normal transfer)
 		peripheral:     uint16(address),  // 7-bit peripheral address
@@ -555,7 +560,7 @@ func (i2c *I2C) controllerReceive(rxBuffer []byte) resultFlag {
 	return result
 }

-// controllerTransmit performs a polling transmit transfer on the I2C bus.
+// controllerReceive performs a polling transmit transfer on the I2C bus.
 func (i2c *I2C) controllerTransmit(txBuffer []byte) resultFlag {
 	txSize := len(txBuffer)
 	for txSize > 0 {
@@ -68,7 +68,7 @@ var (
 )

 // Configure is intended to setup an SPI interface for transmit/receive.
-func (spi *SPI) Configure(config SPIConfig) error {
+func (spi *SPI) Configure(config SPIConfig) {

 	const defaultSpiFreq = 4000000 // 4 MHz

@@ -132,8 +132,6 @@ func (spi *SPI) Configure(config SPIConfig) error {
 	spi.Bus.CR.Set(nxp.LPSPI_CR_MEN)

 	spi.configured = true
-
-	return nil
 }

 // Transfer writes/reads a single byte using the SPI interface.
@@ -12,34 +12,6 @@ import (

 const deviceName = nrf.Device

-var deviceID [8]byte
-
-// DeviceID returns an identifier that is unique within
-// a particular chipset.
-//
-// The identity is one burnt into the MCU itself, or the
-// flash chip at time of manufacture.
-//
-// It's possible that two different vendors may allocate
-// the same DeviceID, so callers should take this into
-// account if needing to generate a globally unique id.
-//
-// The length of the hardware ID is vendor-specific, but
-// 8 bytes (64 bits) is common.
-func DeviceID() []byte {
-	words := make([]uint32, 2)
-	words[0] = nrf.FICR.DEVICEID[0].Get()
-	words[1] = nrf.FICR.DEVICEID[1].Get()
-
-	for i := 0; i < 8; i++ {
-		shift := (i % 4) * 8
-		w := i / 4
-		deviceID[i] = byte(words[w] >> shift)
-	}
-
-	return deviceID[:]
-}
-
 const (
 	PinInput         PinMode = (nrf.GPIO_PIN_CNF_DIR_Input << nrf.GPIO_PIN_CNF_DIR_Pos) | (nrf.GPIO_PIN_CNF_INPUT_Connect << nrf.GPIO_PIN_CNF_INPUT_Pos)
 	PinInputPullup   PinMode = PinInput | (nrf.GPIO_PIN_CNF_PULL_Pullup << nrf.GPIO_PIN_CNF_PULL_Pos)
@@ -274,8 +246,13 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	i2c.setPins(config.SCL, config.SDA)

 	i2c.mode = config.Mode
+
 	if i2c.mode == I2CModeController {
-		i2c.SetBaudRate(config.Frequency)
+		if config.Frequency >= 400*KHz {
+			i2c.Bus.FREQUENCY.Set(nrf.TWI_FREQUENCY_FREQUENCY_K400)
+		} else {
+			i2c.Bus.FREQUENCY.Set(nrf.TWI_FREQUENCY_FREQUENCY_K100)
+		}

 		i2c.enableAsController()
 	} else {
@@ -285,23 +262,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the I2C frequency. It has the side effect of also
-// enabling the I2C hardware if disabled beforehand.
-//
-//go:inline
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	switch {
-	case br >= 400*KHz:
-		i2c.Bus.SetFREQUENCY(nrf.TWI_FREQUENCY_FREQUENCY_K400)
-	case br >= 250*KHz:
-		i2c.Bus.SetFREQUENCY(nrf.TWI_FREQUENCY_FREQUENCY_K250)
-	default:
-		i2c.Bus.SetFREQUENCY(nrf.TWI_FREQUENCY_FREQUENCY_K100)
-	}
-
-	return nil
-}
-
 // signalStop sends a stop signal to the I2C peripheral and waits for confirmation.
 func (i2c *I2C) signalStop() error {
 	tries := 0
@@ -49,7 +49,7 @@ type SPIConfig struct {
 }

 // Configure is intended to setup the SPI interface.
-func (spi SPI) Configure(config SPIConfig) error {
+func (spi SPI) Configure(config SPIConfig) {
 	// Disable bus to configure it
 	spi.Bus.ENABLE.Set(nrf.SPI_ENABLE_ENABLE_Disabled)

@@ -117,8 +117,6 @@ func (spi SPI) Configure(config SPIConfig) error {

 	// Re-enable bus now that it is configured.
 	spi.Bus.ENABLE.Set(nrf.SPI_ENABLE_ENABLE_Enabled)
-
-	return nil
 }

 // Transfer writes/reads a single byte using the SPI interface.
@@ -197,7 +197,7 @@ type SPIConfig struct {
 }

 // Configure is intended to setup the SPI interface.
-func (spi SPI) Configure(config SPIConfig) error {
+func (spi SPI) Configure(config SPIConfig) {
 	// Disable bus to configure it
 	spi.Bus.ENABLE.Set(nrf.SPIM_ENABLE_ENABLE_Disabled)

@@ -265,8 +265,6 @@ func (spi SPI) Configure(config SPIConfig) error {

 	// Re-enable bus now that it is configured.
 	spi.Bus.ENABLE.Set(nrf.SPIM_ENABLE_ENABLE_Enabled)
-
-	return nil
 }

 // Transfer writes/reads a single byte using the SPI interface.
@@ -13,32 +13,6 @@ func EnterBootloader() {
 	enterBootloader()
 }

-// 13 = 1 + FLASH_RUID_DUMMY_BYTES(4) + FLASH_RUID_DATA_BYTES(8)
-var deviceIDBuf [13]byte
-
-// DeviceID returns an identifier that is unique within
-// a particular chipset.
-//
-// The identity is one burnt into the MCU itself, or the
-// flash chip at time of manufacture.
-//
-// It's possible that two different vendors may allocate
-// the same DeviceID, so callers should take this into
-// account if needing to generate a globally unique id.
-//
-// The length of the hardware ID is vendor-specific, but
-// 8 bytes (64 bits) is common.
-func DeviceID() []byte {
-	deviceIDBuf[0] = 0x4b // FLASH_RUID_CMD
-
-	err := doFlashCommand(deviceIDBuf[:], deviceIDBuf[:])
-	if err != nil {
-		panic(err)
-	}
-
-	return deviceIDBuf[5:13]
-}
-
 // compile-time check for ensuring we fulfill BlockDevice interface
 var _ BlockDevice = flashBlockDevice{}

@@ -93,33 +93,6 @@ static ram_func void flash_enable_xip_via_boot2() {
 	((void (*)(void))boot2_copyout+1)();
 }

-#define IO_QSPI_BASE 0x40018000
-#define IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_BITS         0x00000300
-#define IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_MSB          9
-#define IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_LSB          8
-#define IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_VALUE_LOW    0x2
-#define IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_VALUE_HIGH   0x3
-
-#define XIP_SSI_BASE 0x18000000
-#define ssi_hw ((ssi_hw_t *)XIP_SSI_BASE)
-#define SSI_SR_OFFSET      0x00000028
-#define SSI_DR0_OFFSET     0x00000060
-#define SSI_SR_TFNF_BITS   0x00000002
-#define SSI_SR_RFNE_BITS   0x00000008
-
-void ram_func flash_cs_force(bool high) {
-    uint32_t field_val = high ?
-        IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_VALUE_HIGH :
-        IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_VALUE_LOW;
-
-	// &ioqspi_hw->io[1].ctrl
-	uint32_t *addr = (uint32_t*)(IO_QSPI_BASE + (1 * 8) + 4);
-
-	*addr = ((*addr) & !IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_BITS)
-		| (field_val << IO_QSPI_GPIO_QSPI_SS_CTRL_OUTOVER_LSB);
-
-}
-
 // See https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2_common/hardware_flash/flash.c#L86
 void ram_func flash_range_write(uint32_t offset, const uint8_t *data, size_t count)
 {
@@ -159,42 +132,6 @@ void ram_func flash_erase_blocks(uint32_t offset, size_t count)
 	flash_enable_xip_via_boot2();
 }

-void ram_func flash_do_cmd(const uint8_t *txbuf, uint8_t *rxbuf, size_t count) {
-	flash_connect_internal_fn flash_connect_internal_func = (flash_connect_internal_fn) rom_func_lookup(ROM_FUNC_CONNECT_INTERNAL_FLASH);
-	flash_exit_xip_fn flash_exit_xip_func = (flash_exit_xip_fn) rom_func_lookup(ROM_FUNC_FLASH_EXIT_XIP);
-	flash_flush_cache_fn flash_flush_cache_func = (flash_flush_cache_fn) rom_func_lookup(ROM_FUNC_FLASH_FLUSH_CACHE);
-
-	flash_init_boot2_copyout();
-
-	__compiler_memory_barrier();
-
-	flash_connect_internal_func();
-	flash_exit_xip_func();
-
-	flash_cs_force(0);
-	size_t tx_remaining = count;
-	size_t rx_remaining = count;
-	// We may be interrupted -- don't want FIFO to overflow if we're distracted.
-	const size_t max_in_flight = 16 - 2;
-	while (tx_remaining || rx_remaining) {
-		uint32_t flags = *(uint32_t*)(XIP_SSI_BASE + SSI_SR_OFFSET);
-		bool can_put = !!(flags & SSI_SR_TFNF_BITS);
-		bool can_get = !!(flags & SSI_SR_RFNE_BITS);
-		if (can_put && tx_remaining && rx_remaining - tx_remaining < max_in_flight) {
-			*(uint32_t*)(XIP_SSI_BASE + SSI_DR0_OFFSET) = *txbuf++;
-			--tx_remaining;
-		}
-		if (can_get && rx_remaining) {
-			*rxbuf++ = (uint8_t)*(uint32_t*)(XIP_SSI_BASE + SSI_DR0_OFFSET);
-			--rx_remaining;
-		}
-	}
-	flash_cs_force(1);
-
-	flash_flush_cache_func();
-	flash_enable_xip_via_boot2();
-}
-
 */
 import "C"

@@ -202,19 +139,6 @@ func enterBootloader() {
 	C.reset_usb_boot(0, 0)
 }

-func doFlashCommand(tx []byte, rx []byte) error {
-	if len(tx) != len(rx) {
-		return errFlashInvalidWriteLength
-	}
-
-	C.flash_do_cmd(
-		(*C.uint8_t)(unsafe.Pointer(&tx[0])),
-		(*C.uint8_t)(unsafe.Pointer(&rx[0])),
-		C.ulong(len(tx)))
-
-	return nil
-}
-
 // Flash related code
 const memoryStart = C.XIP_BASE // memory start for purpose of erase

@@ -289,26 +289,7 @@ func (spi SPI) isBusy() bool {

 // tx writes buffer to SPI ignoring Rx.
 func (spi SPI) tx(tx []byte) error {
-	err := spi.StartTx(tx, nil)
-	if err != nil {
-		return err
-	}
-	return spi.Wait()
-}
-
-// IsAsync returns whether the SPI supports async operation (usually DMA).
-//
-// It returns true on the rp2040.
-func (spi SPI) IsAsync() bool {
-	return true
-}
-
-// Start a transfer in the background.
-//
-// After this, another StartTx() or Wait() must be called. The provided byte
-// slices (tx and rx) may only be accessed again after Wait() was called.
-func (spi SPI) StartTx(tx, rx []byte) error {
-	if len(tx) == 0 && len(rx) == 0 {
+	if len(tx) == 0 {
 		// We don't have to do anything.
 		// This avoids a panic in &tx[0] when len(tx) == 0.
 		return nil
@@ -325,15 +306,6 @@ func (spi SPI) StartTx(tx, rx []byte) error {
 		dreq = 18 // DREQ_SPI1_TX
 	}

-	// Wait for the previous transmission to complete.
-	for ch.CTRL_TRIG.Get()&rp.DMA_CH0_CTRL_TRIG_BUSY != 0 {
-	}
-
-	if len(rx) != 0 {
-		// Fallback. We don't support receiving data using DMA yet.
-		return spi.Tx(tx, rx)
-	}
-
 	// Configure the DMA peripheral as follows:
 	//   - set read address, write address, and number of transfer units (bytes)
 	//   - increment read address (in memory), don't increment write address (SSPDR)
@@ -347,19 +319,6 @@ func (spi SPI) StartTx(tx, rx []byte) error {
 		rp.DMA_CH0_CTRL_TRIG_DATA_SIZE_SIZE_BYTE<<rp.DMA_CH0_CTRL_TRIG_DATA_SIZE_Pos |
 		dreq<<rp.DMA_CH0_CTRL_TRIG_TREQ_SEL_Pos |
 		rp.DMA_CH0_CTRL_TRIG_EN)
-	return nil
-}
-
-// Wait until all active transactions (started by StartTx) have finished. The
-// buffers provided in StartTx will be available after this method returns.
-func (spi SPI) Wait() error {
-	// Pick the DMA channel reserved for this SPI peripheral.
-	var ch *dmaChannel
-	if spi.Bus == rp.SPI0 {
-		ch = &dmaChannels[spi0DMAChannel]
-	} else { // SPI1
-		ch = &dmaChannels[spi1DMAChannel]
-	}

 	// Wait until the transfer is complete.
 	// TODO: do this more efficiently:
@@ -2,12 +2,7 @@

 package machine

-import (
-	"device/stm32"
-
-	"runtime/volatile"
-	"unsafe"
-)
+import "device/stm32"

 const deviceName = stm32.Device

@@ -85,20 +80,3 @@ func (p Pin) PortMaskClear() (*uint32, uint32) {
 	pin := uint8(p) % 16
 	return &port.BSRR.Reg, 1 << (pin + 16)
 }
-
-var deviceID [12]byte
-
-// DeviceID returns an identifier that is unique within
-// a particular chipset.
-//
-// The identity is one burnt into the MCU itself.
-//
-// The length of the device ID for STM32 is 12 bytes (96 bits).
-func DeviceID() []byte {
-	for i := 0; i < len(deviceID); i++ {
-		word := (*volatile.Register32)(unsafe.Pointer(deviceIDAddr[i/4])).Get()
-		deviceID[i] = byte(word >> ((i % 4) * 8))
-	}
-
-	return deviceID[:]
-}
@@ -157,12 +157,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	// TODO: implement
-	return errI2CNotImplemented
-}
-
 func (i2c *I2C) Tx(addr uint16, w, r []byte) error {

 	if err := i2c.controllerTransmit(addr, w); nil != err {
@@ -84,12 +84,6 @@ func (i2c *I2C) Configure(config I2CConfig) error {
 	return nil
 }

-// SetBaudRate sets the communication speed for I2C.
-func (i2c *I2C) SetBaudRate(br uint32) error {
-	// TODO: implement
-	return errI2CNotImplemented
-}
-
 func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
 	if len(w) > 0 {
 		if err := i2c.controllerTransmit(addr, w); nil != err {
@@ -21,7 +21,7 @@ type SPIConfig struct {
 }

 // Configure is intended to setup the STM32 SPI1 interface.
-func (spi SPI) Configure(config SPIConfig) error {
+func (spi SPI) Configure(config SPIConfig) {

 	// -- CONFIGURING THE SPI IN MASTER MODE --
 	//
@@ -93,8 +93,6 @@ func (spi SPI) Configure(config SPIConfig) error {

 	// enable SPI
 	spi.Bus.CR1.SetBits(stm32.SPI_CR1_SPE)
-
-	return nil
 }

 // Transfer writes/reads a single byte using the SPI interface.
@@ -15,8 +15,6 @@ func CPUFrequency() uint32 {
 	return 72000000
 }

-var deviceIDAddr = []uintptr{0x1FFFF7E8, 0x1FFFF7EC, 0x1FFFF7F0}
-
 // Internal use: configured speed of the APB1 and APB2 timers, this should be kept
 // in sync with any changes to runtime package which configures the oscillators
 // and clock frequencies
@@ -14,8 +14,6 @@ import (
 	"unsafe"
 )

-var deviceIDAddr = []uintptr{0x1FFF7A10, 0x1FFF7A14, 0x1FFF7A18}
-
 const (
 	PA0  = portA + 0
 	PA1  = portA + 1
@@ -11,8 +11,6 @@ import (
 	"unsafe"
 )

-var deviceIDAddr = []uintptr{0x1FF0F420, 0x1FF0F424, 0x1FF0F428}
-
 // Alternative peripheral pin functions
 const (
 	AF0_SYSTEM                               = 0
@@ -13,8 +13,6 @@ func CPUFrequency() uint32 {
 	return 32000000
 }

-var deviceIDAddr = []uintptr{0x1FF80050, 0x1FF80054, 0x1FF80058}
-
 // Internal use: configured speed of the APB1 and APB2 timers, this should be kept
 // in sync with any changes to runtime package which configures the oscillators
 // and clock frequencies
@@ -13,8 +13,6 @@ import (

 // Peripheral abstraction layer for the stm32l4

-var deviceIDAddr = []uintptr{0x1FFF7590, 0x1FFF7594, 0x1FFF7598}
-
 const (
 	AF0_SYSTEM             = 0
 	AF1_TIM1_2_LPTIM1      = 1
@@ -11,8 +11,6 @@ import (
 	"unsafe"
 )

-var deviceIDAddr = []uintptr{0x0BFA0590, 0x0BFA0594, 0x0BFA0598}
-
 const (
 	AF0_SYSTEM                                = 0
 	AF1_TIM1_2_5_8_LPTIM1                     = 1
@@ -14,8 +14,6 @@ import (
 	"unsafe"
 )

-var deviceIDAddr = []uintptr{0x1FFF7590, 0x1FFF7594, 0x1FFF7598}
-
 const (
 	AF0_SYSTEM             = 0
 	AF1_TIM1_2_LPTIM1      = 1
@@ -1,29 +0,0 @@
-//go:build !baremetal || atmega || esp32 || fe310 || k210 || nrf || (nxp && !mk66f18) || atsamd21 || (stm32 && !stm32f7x2 && !stm32l5x2)
-
-package machine
-
-// This is a non-async implementation of the async SPI calls.
-// It is useful for devices that don't support DMA on SPI, or for which it
-// hasn't been implemented yet.
-
-// IsAsync returns whether the SPI supports async operation (usually DMA).
-//
-// This SPI does not support async operations.
-func (s SPI) IsAsync() bool {
-	return false
-}
-
-// Start a transfer in the background.
-//
-// Because this SPI implementation doesn't support async operation, it is an
-// alias for Tx.
-func (s SPI) StartTx(tx, rx []byte) error {
-	return s.Tx(tx, rx)
-}
-
-// Wait until all active transactions (started by StartTx) have finished.
-//
-// This is a no-op on this SPI implementation.
-func (s SPI) Wait() error {
-	return nil
-}
@@ -16,17 +16,3 @@ var (
 	ErrTxInvalidSliceSize      = errors.New("SPI write and read slices must be same size")
 	errSPIInvalidMachineConfig = errors.New("SPI port was not configured properly by the machine")
 )
-
-// If you are getting a compile error on this line please check to see you've
-// correctly implemented the methods on the SPI type. They must match
-// the interface method signatures type to type perfectly.
-// If not implementing the SPI type please remove your target from the build tags
-// at the top of this file.
-var _ interface { // 2
-	Configure(config SPIConfig) error
-	Tx(w, r []byte) error
-	Transfer(w byte) (byte, error)
-	IsAsync() bool
-	StartTx(tx, rx []byte) error
-	Wait() error
-} = (*SPI)(nil)
@@ -10,7 +10,8 @@ func Callers(skip int, pc []uintptr) int {
 var buildVersion string

 // Version returns the Tinygo tree's version string.
-// It is the same as goenv.Version().
+// It is the same as goenv.Version, or in case of a development build,
+// it will be the concatenation of goenv.Version and the git commit hash.
 func Version() string {
 	return buildVersion
 }
@@ -17,11 +17,11 @@
 //
 // | object type | size | bitstring | note
 // |-------------|------|-----------|------
-// | int         | 1    |   0       | no pointers in this object
-// | string      | 2    |  01       | {pointer, len} pair so there is one pointer
-// | []int       | 3    | 001       | {pointer, len, cap}
-// | [4]*int     | 1    |   1       | even though it contains 4 pointers, an array repeats so it can be stored with size=1
-// | [30]byte    | 1    |   0       | there are no pointers so the layout is very simple
+// | int         | 1    | 0         | no pointers in this object
+// | string      | 2    | 10        | {pointer, len} pair so there is one pointer
+// | []int       | 3    | 100       | {pointer, len, cap}
+// | [4]*int     | 1    | 1         | even though it contains 4 pointers, an array repeats so it can be stored with size=1
+// | [30]byte    | 1    | 0         | there are no pointers so the layout is very simple
 //
 // The garbage collector scans objects by starting at the first word value in
 // the object. If the least significant bit of the bitstring is clear, it is
@@ -9,7 +9,7 @@
 	"libc":          "wasi-libc",
 	"rtlib":         "compiler-rt",
 	"scheduler":     "asyncify",
-	"default-stack-size": 65536,
+	"default-stack-size": 32768,
 	"cflags": [
 		"-mbulk-memory",
 		"-mnontrapping-fptoint",
@@ -22,5 +22,5 @@
 	"extra-files": [
 		"src/runtime/asm_tinygowasm.S"
 	],
-	"emulator":      "wasmtime --dir={tmpDir}::/tmp {}"
+	"emulator":      "wasmtime --mapdir=/tmp::{tmpDir} {}"
 }
@@ -9,7 +9,7 @@
 	"libc":          "wasi-libc",
 	"rtlib":         "compiler-rt",
 	"scheduler":     "asyncify",
-	"default-stack-size": 65536,
+	"default-stack-size": 32768,
 	"cflags": [
 		"-mbulk-memory",
 		"-mnontrapping-fptoint",
@@ -10,9 +10,11 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"runtime"
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
 	"text/template"
 	"unicode"
 )
@@ -1441,6 +1443,31 @@ __isr_vector:
 	return w.Flush()
 }

+// Process a single SVD file, synchronously.
+func processFile(infile, outdir, sourceURL, interruptSystem string) error {
+	device, err := readSVD(infile, sourceURL)
+	if err != nil {
+		return fmt.Errorf("failed to read: %w", err)
+	}
+	err = writeGo(outdir, device, interruptSystem)
+	if err != nil {
+		return fmt.Errorf("failed to write Go file: %w", err)
+	}
+	switch interruptSystem {
+	case "software":
+		// Nothing to do.
+	case "hardware":
+		err = writeAsm(outdir, device)
+		if err != nil {
+			return fmt.Errorf("failed to write assembly file: %w", err)
+		}
+	default:
+		return fmt.Errorf("unknown interrupt system: %s", interruptSystem)
+	}
+	return nil
+}
+
+// Process an entire directory, in parallel.
 func generate(indir, outdir, sourceURL, interruptSystem string) error {
 	if _, err := os.Stat(indir); errors.Is(err, fs.ErrNotExist) {
 		fmt.Fprintln(os.Stderr, "cannot find input directory:", indir)
@@ -1448,35 +1475,52 @@ func generate(indir, outdir, sourceURL, interruptSystem string) error {
 	}
 	os.MkdirAll(outdir, 0777)

+	// Read list of SVD files to process.
 	infiles, err := filepath.Glob(filepath.Join(indir, "*.svd"))
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "could not read .svd files:", err)
 		os.Exit(1)
 	}
 	sort.Strings(infiles)
-	for _, infile := range infiles {
-		fmt.Println(infile)
-		device, err := readSVD(infile, sourceURL)
-		if err != nil {
-			return fmt.Errorf("failed to read: %w", err)
-		}
-		err = writeGo(outdir, device, interruptSystem)
-		if err != nil {
-			return fmt.Errorf("failed to write Go file: %w", err)
-		}
-		switch interruptSystem {
-		case "software":
-			// Nothing to do.
-		case "hardware":
-			err = writeAsm(outdir, device)
-			if err != nil {
-				return fmt.Errorf("failed to write assembly file: %w", err)
+
+	// Start worker goroutines.
+	var wg sync.WaitGroup
+	workChan := make(chan string)
+	errChan := make(chan error, 1)
+	for i := 0; i < runtime.NumCPU(); i++ {
+		go func() {
+			for infile := range workChan {
+				err := processFile(infile, outdir, sourceURL, interruptSystem)
+				if err != nil {
+					// Store error to errChan if no error was stored before.
+					select {
+					case errChan <- err:
+					default:
+					}
+				}
+				wg.Done()
 			}
-		default:
-			return fmt.Errorf("unknown interrupt system: %s", interruptSystem)
-		}
+		}()
+	}
+
+	// Submit all jobs to the goroutines.
+	wg.Add(len(infiles))
+	for _, filepath := range infiles {
+		fmt.Println(filepath)
+		workChan <- filepath
+	}
+	close(workChan)
+
+	// Wait until all workers have finished.
+	wg.Wait()
+
+	// Check for an error.
+	select {
+	case err := <-errChan:
+		return err
+	default:
+		return nil
 	}
-	return nil
 }

 func main() {
@@ -145,7 +145,7 @@ func compileGoFileForTesting(t *testing.T, filename string) llvm.Module {
 	defer machine.Dispose()

 	// Load entire program AST into memory.
-	lprogram, err := loader.Load(config, filename, types.Config{
+	lprogram, err := loader.Load(config, filename, config.ClangHeaders, types.Config{
 		Sizes: compiler.Sizes(machine),
 	})
 	if err != nil {