compiler: add support for the `go` keyword on interface methods

This is a feature that was long missing, but because of the previous
refactor, it is now trivial to implement.

compiler/goroutine.go

@@ -79,7 +79,15 @@ func (b *builder) createGo(instr *ssa.Go) {
 		}
 		b.createBuiltin(argTypes, argValues, builtin.Name(), instr.Pos())
 		return
-	} else if !instr.Call.IsInvoke() {
+	} else if instr.Call.IsInvoke() {
+		// This is a method call on an interface value.
+		itf := b.getValue(instr.Call.Value)
+		itfTypeCode := b.CreateExtractValue(itf, 0, "")
+		itfValue := b.CreateExtractValue(itf, 1, "")
+		funcPtr = b.getInvokeFunction(&instr.Call)
+		params = append([]llvm.Value{itfValue}, params...) // start with receiver
+		params = append(params, itfTypeCode)               // end with typecode
+	} else {
 		// This is a function pointer.
 		// At the moment, two extra params are passed to the newly started
 		// goroutine:
@@ -99,9 +107,6 @@ func (b *builder) createGo(instr *ssa.Go) {
 			panic("unknown scheduler type")
 		}
 		prefix = b.fn.RelString(nil)
-	} else {
-		b.addError(instr.Pos(), "todo: go on interface call")
-		return
 	}
 
 	paramBundle := b.emitPointerPack(params)

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

@@ -9,6 +9,8 @@ target triple = "armv7m-unknown-unknown-eabi"
 %"internal/task.state" = type { i32, i32* }
 %runtime.chanSelectState = type { %runtime.channel*, i8* }
 
+@"main.startInterfaceMethod$string" = internal unnamed_addr constant [4 x i8] c"test", align 1
+
 declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*)
 
 ; Function Attrs: nounwind
@@ -158,8 +160,50 @@ entry:
 
 declare void @runtime.chanClose(%runtime.channel* dereferenceable_or_null(32), i8*, i8*)
 
+; Function Attrs: nounwind
+define hidden void @main.startInterfaceMethod(i32 %itf.typecode, i8* %itf.value, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %0 = call i8* @runtime.alloc(i32 16, i8* undef, i8* null) #0
+  %1 = bitcast i8* %0 to i8**
+  store i8* %itf.value, i8** %1, align 4
+  %2 = getelementptr inbounds i8, i8* %0, i32 4
+  %.repack = bitcast i8* %2 to i8**
+  store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @"main.startInterfaceMethod$string", i32 0, i32 0), i8** %.repack, align 4
+  %.repack1 = getelementptr inbounds i8, i8* %0, i32 8
+  %3 = bitcast i8* %.repack1 to i32*
+  store i32 4, i32* %3, align 4
+  %4 = getelementptr inbounds i8, i8* %0, i32 12
+  %5 = bitcast i8* %4 to i32*
+  store i32 %itf.typecode, i32* %5, align 4
+  %stacksize = call i32 @"internal/task.getGoroutineStackSize"(i32 ptrtoint (void (i8*)* @"interface:{Print:func:{basic:string}{}}.Print$invoke$gowrapper" to i32), i8* undef, i8* undef) #0
+  call void @"internal/task.start"(i32 ptrtoint (void (i8*)* @"interface:{Print:func:{basic:string}{}}.Print$invoke$gowrapper" to i32), i8* nonnull %0, i32 %stacksize, i8* undef, i8* null) #0
+  ret void
+}
+
+declare void @"interface:{Print:func:{basic:string}{}}.Print$invoke"(i8*, i8*, i32, i32, i8*, i8*) #5
+
+; Function Attrs: nounwind
+define linkonce_odr void @"interface:{Print:func:{basic:string}{}}.Print$invoke$gowrapper"(i8* %0) unnamed_addr #6 {
+entry:
+  %1 = bitcast i8* %0 to i8**
+  %2 = load i8*, i8** %1, align 4
+  %3 = getelementptr inbounds i8, i8* %0, i32 4
+  %4 = bitcast i8* %3 to i8**
+  %5 = load i8*, i8** %4, align 4
+  %6 = getelementptr inbounds i8, i8* %0, i32 8
+  %7 = bitcast i8* %6 to i32*
+  %8 = load i32, i32* %7, align 4
+  %9 = getelementptr inbounds i8, i8* %0, i32 12
+  %10 = bitcast i8* %9 to i32*
+  %11 = load i32, i32* %10, align 4
+  call void @"interface:{Print:func:{basic:string}{}}.Print$invoke"(i8* %2, i8* %5, i32 %8, i32 %11, i8* undef, i8* undef) #0
+  ret void
+}
+
 attributes #0 = { nounwind }
 attributes #1 = { nounwind "tinygo-gowrapper"="main.regularFunction" }
 attributes #2 = { nounwind "tinygo-gowrapper"="main.inlineFunctionGoroutine$1" }
 attributes #3 = { nounwind "tinygo-gowrapper"="main.closureFunctionGoroutine$1" }
 attributes #4 = { nounwind "tinygo-gowrapper" }
+attributes #5 = { "tinygo-invoke"="reflect/methods.Print(string)" "tinygo-methods"="reflect/methods.Print(string)" }
+attributes #6 = { nounwind "tinygo-gowrapper"="interface:{Print:func:{basic:string}{}}.Print$invoke" }

compiler/testdata/goroutine-wasm.ll

@@ -14,6 +14,7 @@ target triple = "wasm32-unknown-wasi"
 @"main.inlineFunctionGoroutine$pack" = private unnamed_addr constant { i32, i8* } { i32 5, i8* undef }
 @"reflect/types.funcid:func:{basic:int}{}" = external constant i8
 @"main.closureFunctionGoroutine$1$withSignature" = linkonce_odr constant %runtime.funcValueWithSignature { i32 ptrtoint (void (i32, i8*, i8*)* @"main.closureFunctionGoroutine$1" to i32), i8* @"reflect/types.funcid:func:{basic:int}{}" }
+@"main.startInterfaceMethod$string" = internal unnamed_addr constant [4 x i8] c"test", align 1
 
 declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*)
 
@@ -115,4 +116,26 @@ entry:
 
 declare void @runtime.chanClose(%runtime.channel* dereferenceable_or_null(32), i8*, i8*)
 
+; Function Attrs: nounwind
+define hidden void @main.startInterfaceMethod(i32 %itf.typecode, i8* %itf.value, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %0 = call i8* @runtime.alloc(i32 16, i8* undef, i8* null) #0
+  %1 = bitcast i8* %0 to i8**
+  store i8* %itf.value, i8** %1, align 4
+  %2 = getelementptr inbounds i8, i8* %0, i32 4
+  %.repack = bitcast i8* %2 to i8**
+  store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @"main.startInterfaceMethod$string", i32 0, i32 0), i8** %.repack, align 4
+  %.repack1 = getelementptr inbounds i8, i8* %0, i32 8
+  %3 = bitcast i8* %.repack1 to i32*
+  store i32 4, i32* %3, align 4
+  %4 = getelementptr inbounds i8, i8* %0, i32 12
+  %5 = bitcast i8* %4 to i32*
+  store i32 %itf.typecode, i32* %5, align 4
+  call void @"internal/task.start"(i32 ptrtoint (void (i8*, i8*, i32, i32, i8*, i8*)* @"interface:{Print:func:{basic:string}{}}.Print$invoke" to i32), i8* nonnull %0, i32 undef, i8* undef, i8* null) #0
+  ret void
+}
+
+declare void @"interface:{Print:func:{basic:string}{}}.Print$invoke"(i8*, i8*, i32, i32, i8*, i8*) #1
+
 attributes #0 = { nounwind }
+attributes #1 = { "tinygo-invoke"="reflect/methods.Print(string)" "tinygo-methods"="reflect/methods.Print(string)" }

compiler/testdata/goroutine.go

@@ -41,3 +41,11 @@ func closeBuiltinGoroutine(ch chan int) {
 }
 
 func regularFunction(x int)
+
+type simpleInterface interface {
+	Print(string)
+}
+
+func startInterfaceMethod(itf simpleInterface) {
+	go itf.Print("test")
+}

testdata/goroutines.go

@@ -75,6 +75,8 @@ func main() {
 
 	testGoOnBuiltins()
 
+	testGoOnInterface(Foo(0))
+
 	testCond()
 
 	testIssue1790()
@@ -203,6 +205,14 @@ func testCond() {
 
 var once sync.Once
 
+func testGoOnInterface(f Itf) {
+	go f.Nowait()
+	time.Sleep(time.Millisecond)
+	go f.Wait()
+	time.Sleep(time.Millisecond * 2)
+	println("done with 'go on interface'")
+}
+
 // This tests a fix for issue 1790:
 // https://github.com/tinygo-org/tinygo/issues/1790
 func testIssue1790() *int {
@@ -210,3 +220,20 @@ func testIssue1790() *int {
 	i := 0
 	return &i
 }
+
+type Itf interface {
+	Nowait()
+	Wait()
+}
+
+type Foo string
+
+func (f Foo) Nowait() {
+	println("called: Foo.Nowait")
+}
+
+func (f Foo) Wait() {
+	println("called: Foo.Wait")
+	time.Sleep(time.Microsecond)
+	println("  ...waited")
+}

testdata/goroutines.txt

@@ -20,3 +20,7 @@ acquired mutex from goroutine
 released mutex from goroutine
 re-acquired mutex
 done
+called: Foo.Nowait
+called: Foo.Wait
+  ...waited
+done with 'go on interface'