all: update to version 0.25.0

CHANGELOG.md

@@ -1,3 +1,58 @@
+0.25.0
+---
+
+* **command line**
+  - change to ignore PortReset failures
+* **compiler**
+  - `compiler`: darwin/arm64 is aarch64, not arm
+  - `compiler`: don't clobber X18 and FP registers on darwin/arm64
+  - `compiler`: fix issue with methods on generic structs
+  - `compiler`: do not try to build generic functions
+  - `compiler`: fix type names for generic named structs
+  - `compiler`: fix multiple defined function issue for generic functions
+  - `compiler`: implement `unsafe.Alignof` and `unsafe.Sizeof` for generic code
+* **standard library**
+  - `machine`: add DTR and RTS to Serialer interface
+  - `machine`: reorder pin definitions to improve pin list on tinygo.org
+  - `machine/usb`: add support for MIDI
+  - `machine/usb`: adjust buffer alignment (samd21, samd51, nrf52840)
+  - `machine/usb/midi`: add `NoteOn`, `NoteOff`, and `SendCC` methods
+  - `machine/usb/midi`: add definition of MIDI note number
+  - `runtime`: add benchmarks for memhash
+  - `runtime`: add support for printing slices via print/println
+* **targets**
+  - `avr`: fix some apparent mistake in atmega1280/atmega2560 pin constants
+  - `esp32`: provide hardware pin constants
+  - `esp32`: fix WDT reset on the MCH2022 badge
+  - `esp32`: optimize SPI transmit
+  - `esp32c3`: provide hardware pin constants
+  - `esp8266`: provide hardware pin constants like `GPIO2`
+  - `nrf51`: define and use `P0_xx` constants
+  - `nrf52840`, `samd21`, `samd51`: unify bootloader entry process
+  - `nrf52840`, `samd21`, `samd51`: change usbSetup and sendZlp to public
+  - `nrf52840`, `samd21`, `samd51`: refactor handleStandardSetup and initEndpoint
+  - `nrf52840`, `samd21`, `samd51`: improve usb-device initialization
+  - `nrf52840`, `samd21`, `samd51`: move usbcdc to machine/usb/cdc
+  - `rp2040`: add usb serial vendor/product ID
+  - `rp2040`: add support for usb
+  - `rp2040`: change default for serial to usb
+  - `rp2040`: add support for `machine.EnterBootloader`
+  - `rp2040`: turn off pullup/down when input type is not specified
+  - `rp2040`: make picoprobe default openocd interface
+  - `samd51`: add support for `DAC1`
+  - `samd51`: improve TRNG
+  - `wasm`: stub `runtime.buffered`, `runtime.getchar`
+  - `wasi`: make leveldb runtime hash the default
+* **boards**
+  - add Challenger RP2040 LoRa
+  - add MCH2022 badge
+  - add XIAO RP2040
+  - `clue`: remove pins `D21`..`D28`
+  - `feather-rp2040`, `macropad-rp2040`: fix qspi-flash settings
+  - `xiao-ble`: add support for flash-1200-bps-reset
+  - `gopherbot`, `gopherbot2`: add these aliases to simplify for newer users
+
+
 0.24.0
 ---
 

builder/build.go

@@ -1228,15 +1228,10 @@ func determineStackSizes(mod llvm.Module, executable string) ([]string, map[stri
 	// Goroutines need to be started and finished and take up some stack space
 	// that way. This can be measured by measuing the stack size of
 	// tinygo_startTask.
-	var baseStackSize uint64
-	var baseStackSizeType stacksize.SizeType
-	var baseStackSizeFailedAt *stacksize.CallNode
-	if len(gowrappers) != 0 {
-		if numFuncs := len(functions["tinygo_startTask"]); numFuncs != 1 {
-			return nil, nil, fmt.Errorf("expected exactly one definition of tinygo_startTask, got %d", numFuncs)
-		}
-		baseStackSize, baseStackSizeType, baseStackSizeFailedAt = functions["tinygo_startTask"][0].StackSize()
+	if numFuncs := len(functions["tinygo_startTask"]); numFuncs != 1 {
+		return nil, nil, fmt.Errorf("expected exactly one definition of tinygo_startTask, got %d", numFuncs)
 	}
+	baseStackSize, baseStackSizeType, baseStackSizeFailedAt := functions["tinygo_startTask"][0].StackSize()
 
 	sizes := make(map[string]functionStackSize)
 
@@ -1308,11 +1303,6 @@ func modifyStackSizes(executable string, stackSizeLoads []string, stackSizes map
 	if err != nil {
 		return err
 	}
-	if data == nil {
-		// The .tinygo_stacksizes section doesn't exist, so assume this
-		// modification isn't needed.
-		return nil
-	}
 
 	if len(stackSizeLoads)*4 != len(data) {
 		// Note: while AVR should use 2 byte stack sizes, even 64-bit platforms

builder/elfpatch.go

@@ -15,7 +15,7 @@ func getElfSectionData(executable string, sectionName string) ([]byte, elf.FileH
 
 	section := elfFile.Section(sectionName)
 	if section == nil {
-		return nil, elf.FileHeader{}, nil
+		return nil, elf.FileHeader{}, fmt.Errorf("could not find %s section", sectionName)
 	}
 
 	data, err := section.Data()

compiler/compiler.go

@@ -1039,9 +1039,17 @@ func (b *builder) createFunctionStart() {
 		b.addError(b.fn.Pos(), errValue)
 		return
 	}
+
 	b.addStandardDefinedAttributes(b.llvmFn)
 	if !b.info.exported {
-		b.llvmFn.SetVisibility(llvm.HiddenVisibility)
+		// Do not set visibility for local linkage (internal or private).
+		// Otherwise a "local linkage requires default visibility"
+		// assertion error in llvm-project/llvm/include/llvm/IR/GlobalValue.h:236
+		// is thrown.
+		if b.llvmFn.Linkage() != llvm.InternalLinkage &&
+			b.llvmFn.Linkage() != llvm.PrivateLinkage {
+			b.llvmFn.SetVisibility(llvm.HiddenVisibility)
+		}
 		b.llvmFn.SetUnnamedAddr(true)
 	}
 	if b.info.section != "" {
@@ -1265,6 +1273,7 @@ func (b *builder) createFunction() {
 	// Create anonymous functions (closures etc.).
 	for _, sub := range b.fn.AnonFuncs {
 		b := newBuilder(b.compilerContext, b.Builder, sub)
+		b.llvmFn.SetLinkage(llvm.InternalLinkage)
 		b.createFunction()
 	}
 }

compiler/testdata/basic.ll

@@ -196,7 +196,7 @@ entry:
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.foo$1"(%main.kv.0* dereferenceable_or_null(1) %b, i8* %context) unnamed_addr #1 {
+define internal void @"main.foo$1"(%main.kv.0* dereferenceable_or_null(1) %b, i8* %context) unnamed_addr #1 {
 entry:
   ret void
 }

compiler/testdata/defer-cortex-m-qemu.ll

@@ -115,7 +115,7 @@ declare i8* @llvm.stacksave() #2
 declare void @runtime.setupDeferFrame(%runtime.deferFrame* dereferenceable_or_null(24), i8*, i8*) #0
 
 ; Function Attrs: nounwind
-define hidden void @"main.deferSimple$1"(i8* %context) unnamed_addr #1 {
+define internal void @"main.deferSimple$1"(i8* %context) unnamed_addr #1 {
 entry:
   call void @runtime.printint32(i32 3, i8* undef) #3
   ret void
@@ -246,14 +246,14 @@ rundefers.end9:                                   ; preds = %rundefers.loophead1
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.deferMultiple$1"(i8* %context) unnamed_addr #1 {
+define internal void @"main.deferMultiple$1"(i8* %context) unnamed_addr #1 {
 entry:
   call void @runtime.printint32(i32 3, i8* undef) #3
   ret void
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.deferMultiple$2"(i8* %context) unnamed_addr #1 {
+define internal void @"main.deferMultiple$2"(i8* %context) unnamed_addr #1 {
 entry:
   call void @runtime.printint32(i32 5, i8* undef) #3
   ret void

compiler/testdata/goroutine-cortex-m-qemu-tasks.ll

@@ -51,7 +51,7 @@ entry:
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.inlineFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
+define internal void @"main.inlineFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
 entry:
   ret void
 }
@@ -84,7 +84,7 @@ entry:
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.closureFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
+define internal void @"main.closureFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
 entry:
   %unpack.ptr = bitcast i8* %context to i32*
   store i32 7, i32* %unpack.ptr, align 4

compiler/testdata/goroutine-wasm-asyncify.ll

@@ -53,7 +53,7 @@ entry:
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.inlineFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
+define internal void @"main.inlineFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
 entry:
   ret void
 }
@@ -90,7 +90,7 @@ entry:
 }
 
 ; Function Attrs: nounwind
-define hidden void @"main.closureFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
+define internal void @"main.closureFunctionGoroutine$1"(i32 %x, i8* %context) unnamed_addr #1 {
 entry:
   %unpack.ptr = bitcast i8* %context to i32*
   store i32 7, i32* %unpack.ptr, align 4

goenv/version.go

@@ -12,7 +12,7 @@ import (
 
 // Version of TinyGo.
 // Update this value before release of new version of software.
-const Version = "0.25.0-dev"
+const Version = "0.25.0"
 
 var (
 	// This variable is set at build time using -ldflags parameters.

src/internal/task/task_asyncify.go

@@ -99,9 +99,9 @@ func Pause() {
 //export tinygo_unwind
 func (*stackState) unwind()
 
-// Switch to this task until it pauses or completes.
+// Resume the task until it pauses or completes.
 // This may only be called from the scheduler.
-func (t *Task) Switch() {
+func (t *Task) Resume() {
 	// The current task must be saved and restored because this can nest on WASM with JS.
 	prevTask := currentTask
 	t.gcData.swap()
@@ -121,3 +121,9 @@ func (t *Task) Switch() {
 
 //export tinygo_rewind
 func (*state) rewind()
+
+// OnSystemStack returns whether the caller is running on the system stack.
+func OnSystemStack() bool {
+	// If there is not an active goroutine, then this must be running on the system stack.
+	return Current() == nil
+}

src/internal/task/task_none.go

@@ -28,12 +28,12 @@ func start(fn uintptr, args unsafe.Pointer, stackSize uintptr) {
 
 type state struct{}
 
-func (t *Task) Switch() {
+func (t *Task) Resume() {
 	runtimePanic("scheduler is disabled")
 }
 
-// MainTask returns whether the caller is running in the main goroutine.
-func MainTask() bool {
+// OnSystemStack returns whether the caller is running on the system stack.
+func OnSystemStack() bool {
 	// This scheduler does not do any stack switching.
 	return true
 }

src/internal/task/task_stack.go

@@ -27,12 +27,8 @@ type state struct {
 	canaryPtr *uintptr
 }
 
-// The task struct for the main goroutine.
-var mainTask Task
-
-// currentTask is the current running task. The default value is the main
-// goroutine.
-var currentTask = &mainTask
+// currentTask is the current running task, or nil if currently in the scheduler.
+var currentTask *Task
 
 // Current returns the current active task.
 func Current() *Task {
@@ -40,36 +36,29 @@ func Current() *Task {
 }
 
 // Pause suspends the current task and returns to the scheduler.
-// This function may only be called when running on a goroutine stack, not when in an interrupt.
+// This function may only be called when running on a goroutine stack, not when running on the system stack or in an interrupt.
 func Pause() {
 	// Check whether the canary (the lowest address of the stack) is still
 	// valid. If it is not, a stack overflow has occured.
-	if currentTask.state.canaryPtr != nil && *currentTask.state.canaryPtr != stackCanary {
+	if *currentTask.state.canaryPtr != stackCanary {
 		runtimePanic("goroutine stack overflow")
 	}
-	scheduler()
+	currentTask.state.pause()
 }
 
-//go:linkname scheduler runtime.scheduler
-func scheduler()
-
 //export tinygo_pause
 func pause() {
 	Pause()
 }
 
-// Switch to the given task until it pauses or completes.
+// Resume the task until it pauses or completes.
 // This may only be called from the scheduler.
-func (t *Task) Switch() {
-	current := currentTask
-	if current == t {
-		// Nothing to switch to: we're already in this task.
-		return
-	}
+func (t *Task) Resume() {
 	currentTask = t
 	t.gcData.swap()
-	t.state.switchTo(current)
+	t.state.resume()
 	t.gcData.swap()
+	currentTask = nil
 }
 
 // initialize the state and prepare to call the specified function with the specified argument bundle.
@@ -114,8 +103,8 @@ func start(fn uintptr, args unsafe.Pointer, stackSize uintptr) {
 	runqueuePushBack(t)
 }
 
-// MainTask returns whether the caller is running in the main goroutine.
-func MainTask() bool {
+// OnSystemStack returns whether the caller is running on the system stack.
+func OnSystemStack() bool {
 	// If there is not an active goroutine, then this must be running on the system stack.
-	return currentTask == &mainTask
+	return Current() == nil
 }

src/internal/task/task_stack_386.S

@@ -20,8 +20,11 @@ tinygo_startTask:
     // Branch to the "goroutine start" function.
     calll *%ebx
 
-    // After return, exit this goroutine.
-    calll tinygo_pause
+    // Rebalance the stack (to undo the above push).
+    addl $4, %esp
+
+    // After return, exit this goroutine. This is a tail call.
+    jmp tinygo_pause
     .cfi_endproc
 
 .global tinygo_swapTask

src/internal/task/task_stack_386.go

@@ -5,6 +5,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_386.S that relies on the exact
 // layout of this struct.
@@ -44,12 +46,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.esi = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_amd64.S

@@ -28,11 +28,11 @@ tinygo_startTask:
     // Branch to the "goroutine start" function.
     callq *%r12
 
-    // After return, exit this goroutine.
+    // After return, exit this goroutine. This is a tail call.
     #ifdef __MACH__
-    callq _tinygo_pause
+    jmp _tinygo_pause
     #else
-    callq tinygo_pause
+    jmp tinygo_pause
     #endif
     .cfi_endproc
 

src/internal/task/task_stack_amd64.go

@@ -5,6 +5,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_amd64.S that relies on the exact
 // layout of this struct.
@@ -43,12 +45,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.r13 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_amd64_windows.S

@@ -17,8 +17,8 @@ tinygo_startTask:
     // Branch to the "goroutine start" function.
     callq *%r12
 
-    // After return, exit this goroutine.
-    callq tinygo_pause
+    // After return, exit this goroutine. This is a tail call.
+    jmp tinygo_pause
 
 .global tinygo_swapTask
 .section .text.tinygo_swapTask,"ax"

src/internal/task/task_stack_amd64_windows.go

@@ -8,6 +8,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_amd64_windows.S that relies on
 // the exact layout of this struct.
@@ -48,12 +50,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.r13 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_arm.go

@@ -5,6 +5,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_arm.S that relies on the exact
 // layout of this struct.
@@ -43,12 +45,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.r5 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_arm64.go

@@ -5,6 +5,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_arm64.S that relies on the exact
 // layout of this struct.
@@ -46,12 +48,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.x20 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_avr.S

@@ -1,3 +1,9 @@
+.section .bss.tinygo_systemStack
+.global tinygo_systemStack
+.type   tinygo_systemStack, %object
+tinygo_systemStack:
+    .short 0
+
 .section .text.tinygo_startTask
 .global  tinygo_startTask
 .type    tinygo_startTask, %function

src/internal/task/task_stack_avr.go

@@ -5,6 +5,9 @@ package task
 
 import "unsafe"
 
+//go:extern tinygo_systemStack
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_avr.S that relies on the exact
 // layout of this struct.
@@ -48,12 +51,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.r4r5 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_baremetal.go

@@ -1,12 +0,0 @@
-//go:build scheduler.tasks && baremetal
-// +build scheduler.tasks,baremetal
-
-package task
-
-//go:extern _stack_bottom
-var _stack_bottom uintptr
-
-func init() {
-	mainTask.state.canaryPtr = &_stack_bottom
-	*mainTask.state.canaryPtr = stackCanary
-}

src/internal/task/task_stack_cortexm.S

@@ -30,10 +30,10 @@ tinygo_startTask:
     .cfi_endproc
 .size tinygo_startTask, .-tinygo_startTask
 
-.section .text.tinygo_switchToMain
-.global  tinygo_switchToMain
-.type    tinygo_switchToMain, %function
-tinygo_switchToMain:
+.section .text.tinygo_switchToScheduler
+.global  tinygo_switchToScheduler
+.type    tinygo_switchToScheduler, %function
+tinygo_switchToScheduler:
     .cfi_startproc
     // r0 = sp *uintptr
 
@@ -43,9 +43,9 @@ tinygo_switchToMain:
     subs r1, #36
     str r1, [r0]
 
-    b tinygo_swapTaskInternal
+    b tinygo_swapTask
     .cfi_endproc
-.size tinygo_switchToMain, .-tinygo_switchToMain
+.size tinygo_switchToScheduler, .-tinygo_switchToScheduler
 
 .section .text.tinygo_switchToTask
 .global  tinygo_switchToTask
@@ -55,17 +55,17 @@ tinygo_switchToTask:
     // r0 = sp uintptr
 
     // Currently on the scheduler stack (SP=MSP). We'll have to update the PSP,
-    // and then we can invoke swapTaskInternal.
+    // and then we can invoke swapTask.
     msr PSP, r0
 
-    b.n tinygo_swapTaskInternal
+    b.n tinygo_swapTask
     .cfi_endproc
 .size tinygo_switchToTask, .-tinygo_switchToTask
 
-.section .text.tinygo_swapTaskInternal
-.global  tinygo_swapTaskInternal
-.type    tinygo_swapTaskInternal, %function
-tinygo_swapTaskInternal:
+.section .text.tinygo_swapTask
+.global  tinygo_swapTask
+.type    tinygo_swapTask, %function
+tinygo_swapTask:
     .cfi_startproc
     // This function stores the current register state to the stack, switches to
     // the other stack (MSP/PSP), and loads the register state from the other
@@ -77,15 +77,15 @@ tinygo_swapTaskInternal:
     // used directly. Only very few operations work on them, such as mov. That's
     // why the higher register values are first stored in the temporary register
     // r3 when loading/storing them.
-    // It is possible to reduce the swapTaskInternal by two instructions (~2
-    // cycles) on Cortex-M0 by reordering the layout of the pushed registers
-    // from {r4-r11, lr} to {r8-r11, r4-r8, lr}. However, that also requires a
-    // change on the Go side (depending on thumb1/thumb2!) and so is not really
-    // worth the complexity.
+    // It is possible to reduce the swapTask by two instructions (~2 cycles) on
+    // Cortex-M0 by reordering the layout of the pushed registers from {r4-r11,
+    // lr} to {r8-r11, r4-r8, lr}. However, that also requires a change on the
+    // Go side (depending on thumb1/thumb2!) and so is not really worth the
+    // complexity.
 
     // Store state to old task. It saves the lr instead of the pc, because that
     // will be the pc after returning back to the old task (in a different
-    // invocation of swapTaskInternal).
+    // invocation of swapTask).
     #if defined(__thumb2__)
     push {r4-r11, lr}
     .cfi_def_cfa_offset 9*4
@@ -108,63 +108,6 @@ tinygo_swapTaskInternal:
     msr  CONTROL, r0 // store CONTROL register
     isb              // required to flush the pipeline
 
-    // Load state from new task and branch to the previous position in the
-    // program.
-    #if defined(__thumb2__)
-    pop {r4-r11, pc}
-    #else
-    pop {r4-r7}
-    .cfi_def_cfa_offset 5*9
-    pop {r0-r3}
-    .cfi_def_cfa_offset 1*9
-    mov r8, r0
-    mov r9, r1
-    mov r10, r2
-    mov r11, r3
-    pop {pc}
-    #endif
-    .cfi_endproc
-.size tinygo_swapTaskInternal, .-tinygo_swapTaskInternal
-
-
-.section .text.tinygo_swapTask
-.global  tinygo_swapTask
-.type    tinygo_swapTask, %function
-tinygo_swapTask:
-    .cfi_startproc
-    // This function is like tinygo_swapTaskInternal but only switches the stack
-    // pointer without touching the SPSEL bit (to switch between MSP and PSP).
-    // Therefore, it is used to switch between two tasks that are not the main
-    // goroutine.
-
-    // Store state to old task. It saves the lr instead of the pc, because that
-    // will be the pc after returning back to the old task (in a different
-    // invocation of swapTask).
-    #if defined(__thumb2__)
-    push {r4-r11, lr}
-    .cfi_def_cfa_offset 9*4
-    #else
-    mov r0, r8
-    mov r1, r9
-    mov r2, r10
-    mov r3, r11
-    push {r0-r3, lr}
-    .cfi_def_cfa_offset 5*4
-    push {r4-r7}
-    .cfi_def_cfa_offset 9*4
-    #endif
-
-    // Save the current stack pointer in oldStack.
-    #if defined(__thumb2__)
-    str sp, [r1]
-    #else
-    mov r2, sp
-    str r2, [r1]
-    #endif
-
-    // Switch to the new stack pointer.
-    mov sp, r0
-
     // Load state from new task and branch to the previous position in the
     // program.
     #if defined(__thumb2__)

src/internal/task/task_stack_cortexm.go

@@ -52,23 +52,19 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.r5 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	// This code is probably more complex than it needs to be.
-	// TODO: simplify this, ideally to a single function call.
-	if s == &mainTask.state {
-		switchToMain(&current.state.sp)
-	} else if current == &mainTask {
-		switchToTask(s.sp)
-	} else {
-		swapTask(s.sp, &current.state.sp)
-	}
+func (s *state) resume() {
+	switchToTask(s.sp)
 }
 
 //export tinygo_switchToTask
 func switchToTask(uintptr)
 
-//export tinygo_switchToMain
-func switchToMain(*uintptr)
+//export tinygo_switchToScheduler
+func switchToScheduler(*uintptr)
+
+func (s *state) pause() {
+	switchToScheduler(&s.sp)
+}
 
 // SystemStack returns the system stack pointer. On Cortex-M, it is always
 // available.

src/internal/task/task_stack_esp32.go

@@ -16,6 +16,8 @@ import (
 	"unsafe"
 )
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_esp8266.S that relies on the
 // exact layout of this struct.
@@ -58,12 +60,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.a2 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_esp8266.go

@@ -17,6 +17,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see task_stack_esp8266.S that relies on the
 // exact layout of this struct.
@@ -52,12 +54,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.a13 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/internal/task/task_stack_tinygoriscv.go

@@ -5,6 +5,8 @@ package task
 
 import "unsafe"
 
+var systemStack uintptr
+
 // calleeSavedRegs is the list of registers that must be saved and restored when
 // switching between tasks. Also see scheduler_riscv.S that relies on the
 // exact layout of this struct.
@@ -48,12 +50,18 @@ func (s *state) archInit(r *calleeSavedRegs, fn uintptr, args unsafe.Pointer) {
 	r.s1 = uintptr(args)
 }
 
-func (s *state) switchTo(current *Task) {
-	swapTask(s.sp, &current.state.sp)
+func (s *state) resume() {
+	swapTask(s.sp, &systemStack)
+}
+
+func (s *state) pause() {
+	newStack := systemStack
+	systemStack = 0
+	swapTask(newStack, &s.sp)
 }
 
 // SystemStack returns the system stack pointer when called from a task stack.
 // When called from the system stack, it returns 0.
 func SystemStack() uintptr {
-	return mainTask.state.sp
+	return systemStack
 }

src/runtime/gc_stack_raw.go

@@ -14,7 +14,7 @@ func markStack() {
 	// Scan the current stack, and all current registers.
 	scanCurrentStack()
 
-	if !task.MainTask() {
+	if !task.OnSystemStack() {
 		// Mark system stack.
 		markRoots(getSystemStackPointer(), stackTop)
 	}
@@ -28,7 +28,7 @@ func scanstack(sp uintptr) {
 	// Mark current stack.
 	// This function is called by scanCurrentStack, after pushing all registers onto the stack.
 	// Callee-saved registers have been pushed onto stack by tinygo_localscan, so this will scan them too.
-	if task.MainTask() {
+	if task.OnSystemStack() {
 		// This is the system stack.
 		// Scan all words on the stack.
 		markRoots(sp, stackTop)

src/runtime/runtime_tinygowasm.go

@@ -49,6 +49,16 @@ func putchar(c byte) {
 	}
 }
 
+func getchar() byte {
+	// dummy, TODO
+	return 0
+}
+
+func buffered() int {
+	// dummy, TODO
+	return 0
+}
+
 //go:linkname now time.now
 func now() (sec int64, nsec int32, mono int64) {
 	mono = nanotime()

src/runtime/scheduler.go

@@ -112,7 +112,9 @@ func addSleepTask(t *task.Task, duration timeUnit) {
 	*q = t
 }
 
+// Run the scheduler until all tasks have finished.
 func scheduler() {
+	// Main scheduler loop.
 	var now timeUnit
 	for !schedulerDone {
 		scheduleLog("")
@@ -162,11 +164,7 @@ func scheduler() {
 
 		// Run the given task.
 		scheduleLogTask("  run:", t)
-		t.Switch()
-		if GOARCH != "wasm" {
-			// Don't return when using Asyncify.
-			return
-		}
+		t.Resume()
 	}
 }
 
@@ -183,7 +181,7 @@ func minSched() {
 		}
 
 		scheduleLogTask("  run:", t)
-		t.Switch()
+		t.Resume()
 	}
 	scheduleLog("stop nested scheduler")
 }

src/runtime/scheduler_any.go

@@ -1,5 +1,5 @@
-//go:build scheduler.asyncify
-// +build scheduler.asyncify
+//go:build !scheduler.none
+// +build !scheduler.none
 
 package runtime
 

src/runtime/scheduler_tasks.go

@@ -16,27 +16,3 @@ func getSystemStackPointer() uintptr {
 	}
 	return sp
 }
-
-// Pause the current task for a given time.
-//
-//go:linkname sleep time.Sleep
-func sleep(duration int64) {
-	if duration <= 0 {
-		return
-	}
-
-	addSleepTask(task.Current(), nanosecondsToTicks(duration))
-	task.Pause()
-}
-
-// run is called by the program entry point to execute the go program.
-// The main goroutine runs on the system stack, so initAll and callMain can be
-// called directly.
-func run() {
-	initHeap()
-	initAll()
-	callMain()
-	schedulerDone = true
-}
-
-const hasScheduler = true

targets/arm.ld

@@ -27,7 +27,6 @@ SECTIONS
     .stack (NOLOAD) :
     {
         . = ALIGN(4);
-        _stack_bottom = .;
         . += _stack_size;
         _stack_top = .;
     } >RAM

targets/avr.ld

@@ -19,7 +19,6 @@ SECTIONS
 
     .stack (NOLOAD) :
     {
-        _stack_bottom = .;
         . += _stack_size;
         _stack_top = .;
     } >RAM

targets/esp32.ld

@@ -41,7 +41,6 @@ SECTIONS
     .stack (NOLOAD) :
     {
         . = ALIGN(16);
-        _stack_bottom = .;
         . += _stack_size;
         _stack_top = .;
     } >DRAM

targets/esp32c3.ld

@@ -70,7 +70,6 @@ SECTIONS
     .stack (NOLOAD) :
     {
         . = ALIGN(16);
-        _stack_bottom = .;
         . += _stack_size;
         _stack_top = .;
     } >DRAM

targets/esp8266.ld

@@ -67,11 +67,6 @@ _heap_end = ORIGIN(DRAM) + LENGTH(DRAM);
  */
 _stack_top = 0x40000000;
 
-/* This is the stack bottom according to this forum post:
- * https://bbs.espressif.com/viewtopic.php?t=8879#p19038
- */
-_stack_bottom = 0x3fffeb2c;
-
 /* Functions normally provided by a libc.
  * Source:
  * https://github.com/espressif/ESP8266_NONOS_SDK/blob/master/ld/eagle.rom.addr.v6.ld

targets/maixbit.ld

@@ -57,7 +57,6 @@ SECTIONS
 }
 
 PROVIDE(_stack_top = ORIGIN(RAM) + LENGTH(RAM));
-_stack_bottom = _stack_top - _stack_size;
 
 /* For the memory allocator. */
 _heap_start = _ebss;

targets/mimxrt1062-teensy40.ld

@@ -59,7 +59,6 @@ SECTIONS
   .stack (NOLOAD) : {
 
     . = ALIGN(8);
-    _stack_bottom = .;
     . += _stack_size;
     _stack_top = .;
 

targets/riscv.ld

@@ -19,7 +19,6 @@ SECTIONS
     .stack (NOLOAD) :
     {
         . = ALIGN(16);
-        _stack_bottom = .;
         . += _stack_size;
         _stack_top = .;
     } >RAM

testdata/generics.go

@@ -1,11 +1,19 @@
 package main
 
+import (
+	"github.com/tinygo-org/tinygo/testdata/generics/testa"
+	"github.com/tinygo-org/tinygo/testdata/generics/testb"
+)
+
 func main() {
 	println("add:", Add(3, 5))
 	println("add:", Add(int8(3), 5))
 
 	var c C[int]
 	c.F() // issue 2951
+
+	testa.Test()
+	testb.Test()
 }
 
 type Integer interface {

testdata/generics.txt

@@ -1,2 +1,6 @@
 add: 8
 add: 8
+value: 101
+value: 101
+value: 501
+value: 501

testdata/generics/testa/testa.go

@@ -0,0 +1,20 @@
+package testa
+
+import (
+	"github.com/tinygo-org/tinygo/testdata/generics/value"
+)
+
+func Test() {
+	v := value.New(1)
+	vm := value.Map(v, Plus100)
+	vm.Get(callback, callback)
+}
+
+func callback(v int) {
+	println("value:", v)
+}
+
+// Plus100 is a `Transform` that adds 100 to `value`.
+func Plus100(value int) int {
+	return value + 100
+}

testdata/generics/testb/testb.go

@@ -0,0 +1,20 @@
+package testb
+
+import (
+	"github.com/tinygo-org/tinygo/testdata/generics/value"
+)
+
+func Test() {
+	v := value.New(1)
+	vm := value.Map(v, Plus500)
+	vm.Get(callback, callback)
+}
+
+func callback(v int) {
+	println("value:", v)
+}
+
+// Plus500 is a `Transform` that adds 500 to `value`.
+func Plus500(value int) int {
+	return value + 500
+}

testdata/generics/value/value.go

@@ -0,0 +1,53 @@
+package value
+
+type (
+	Value[T any] interface {
+		Get(Callback[T], Callback[T])
+	}
+
+	Callback[T any] func(T)
+
+	Transform[S any, D any] func(S) D
+)
+
+func New[T any](v T) Value[T] {
+	return &value[T]{
+		v: v,
+	}
+}
+
+type value[T any] struct {
+	v T
+}
+
+func (v *value[T]) Get(fn1, fn2 Callback[T]) {
+	// For example purposes.
+	// Normally would be asynchronous callback.
+	fn1(v.v)
+	fn2(v.v)
+}
+
+func Map[S, D any](v Value[S], tx Transform[S, D]) Value[D] {
+	return &mapper[S, D]{
+		v:  v,
+		tx: tx,
+	}
+}
+
+type mapper[S, D any] struct {
+	v  Value[S]
+	tx Transform[S, D]
+}
+
+func (m *mapper[S, D]) Get(fn1, fn2 Callback[D]) {
+	// two callbacks are passed to generate more than
+	// one anonymous function symbol name.
+	m.v.Get(func(v S) {
+		// anonymous function inside of anonymous function.
+		func() {
+			fn1(m.tx(v))
+		}()
+	}, func(v S) {
+		fn2(m.tx(v))
+	})
+}