compiler: add support for recursive function types

compiler/compiler.go

@@ -23,7 +23,7 @@ import (
 // Version of the compiler pacakge. Must be incremented each time the compiler
 // package changes in a way that affects the generated LLVM module.
 // This version is independent of the TinyGo version number.
-const Version = 22 // last change: check for divide by zero
+const Version = 23 // last change: fix recursive function types
 
 func init() {
 	llvm.InitializeAllTargets()
@@ -76,6 +76,7 @@ type compilerContext struct {
 	targetData       llvm.TargetData
 	intType          llvm.Type
 	i8ptrType        llvm.Type // for convenience
+	rawVoidFuncType  llvm.Type // for convenience
 	funcPtrAddrSpace int
 	uintptrType      llvm.Type
 	program          *ssa.Program
@@ -121,6 +122,7 @@ func newCompilerContext(moduleName string, machine llvm.TargetMachine, config *C
 	dummyFuncType := llvm.FunctionType(c.ctx.VoidType(), nil, false)
 	dummyFunc := llvm.AddFunction(c.mod, "tinygo.dummy", dummyFuncType)
 	c.funcPtrAddrSpace = dummyFunc.Type().PointerAddressSpace()
+	c.rawVoidFuncType = dummyFunc.Type()
 	dummyFunc.EraseFromParentAsFunction()
 
 	return c

compiler/func.go

@@ -23,7 +23,7 @@ func (c *compilerContext) createFuncValue(builder llvm.Builder, funcPtr, context
 	switch c.FuncImplementation {
 	case "doubleword":
 		// Closure is: {context, function pointer}
-		funcValueScalar = funcPtr
+		funcValueScalar = llvm.ConstBitCast(funcPtr, c.rawVoidFuncType)
 	case "switch":
 		funcValueWithSignatureGlobalName := funcPtr.Name() + "$withSignature"
 		funcValueWithSignatureGlobal := c.mod.NamedGlobal(funcValueWithSignatureGlobalName)
@@ -78,11 +78,11 @@ func (b *builder) extractFuncContext(funcValue llvm.Value) llvm.Value {
 // value. This may be an expensive operation.
 func (b *builder) decodeFuncValue(funcValue llvm.Value, sig *types.Signature) (funcPtr, context llvm.Value) {
 	context = b.CreateExtractValue(funcValue, 0, "")
+	llvmSig := b.getRawFuncType(sig)
 	switch b.FuncImplementation {
 	case "doubleword":
-		funcPtr = b.CreateExtractValue(funcValue, 1, "")
+		funcPtr = b.CreateBitCast(b.CreateExtractValue(funcValue, 1, ""), llvmSig, "")
 	case "switch":
-		llvmSig := b.getRawFuncType(sig)
 		sigGlobal := b.getFuncSignatureID(sig)
 		funcPtr = b.createRuntimeCall("getFuncPtr", []llvm.Value{funcValue, sigGlobal}, "")
 		funcPtr = b.CreateIntToPtr(funcPtr, llvmSig, "")
@@ -96,8 +96,7 @@ func (b *builder) decodeFuncValue(funcValue llvm.Value, sig *types.Signature) (f
 func (c *compilerContext) getFuncType(typ *types.Signature) llvm.Type {
 	switch c.FuncImplementation {
 	case "doubleword":
-		rawPtr := c.getRawFuncType(typ)
-		return c.ctx.StructType([]llvm.Type{c.i8ptrType, rawPtr}, false)
+		return c.ctx.StructType([]llvm.Type{c.i8ptrType, c.rawVoidFuncType}, false)
 	case "switch":
 		return c.getLLVMRuntimeType("funcValue")
 	default:

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

@@ -103,7 +103,7 @@ entry:
 declare void @runtime.printint32(i32, i8*, i8*)
 
 ; Function Attrs: nounwind
-define hidden void @main.funcGoroutine(i8* %fn.context, void (i32, i8*, i8*)* %fn.funcptr, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+define hidden void @main.funcGoroutine(i8* %fn.context, void ()* %fn.funcptr, i8* %context, i8* %parentHandle) unnamed_addr #0 {
 entry:
   %0 = call i8* @runtime.alloc(i32 12, i8* undef, i8* null) #0
   %1 = bitcast i8* %0 to i32*
@@ -112,8 +112,8 @@ entry:
   %3 = bitcast i8* %2 to i8**
   store i8* %fn.context, i8** %3, align 4
   %4 = getelementptr inbounds i8, i8* %0, i32 8
-  %5 = bitcast i8* %4 to void (i32, i8*, i8*)**
-  store void (i32, i8*, i8*)* %fn.funcptr, void (i32, i8*, i8*)** %5, align 4
+  %5 = bitcast i8* %4 to void ()**
+  store void ()* %fn.funcptr, void ()** %5, align 4
   %stacksize = call i32 @"internal/task.getGoroutineStackSize"(i32 ptrtoint (void (i8*)* @main.funcGoroutine.gowrapper to i32), i8* undef, i8* undef) #0
   call void @"internal/task.start"(i32 ptrtoint (void (i8*)* @main.funcGoroutine.gowrapper to i32), i8* nonnull %0, i32 %stacksize, i8* undef, i8* null) #0
   ret void

testdata/calls.go

@@ -228,3 +228,7 @@ type issue1304 struct {
 func (x issue1304) call() {
 	// nothing to do
 }
+
+type recursiveFuncType func(recursiveFuncType)
+
+var recursiveFunction recursiveFuncType

transform/interrupt.go

@@ -66,7 +66,8 @@ func LowerInterrupts(mod llvm.Module, sizeLevel int) []error {
 	softwareVector := make(map[int64]llvm.Value)
 
 	ctx := mod.Context()
-	nullptr := llvm.ConstNull(llvm.PointerType(ctx.Int8Type(), 0))
+	i8ptrType := llvm.PointerType(ctx.Int8Type(), 0)
+	nullptr := llvm.ConstNull(i8ptrType)
 	builder := ctx.NewBuilder()
 	defer builder.Dispose()
 
@@ -236,6 +237,8 @@ func LowerInterrupts(mod llvm.Module, sizeLevel int) []error {
 			// Fill the function declaration with the forwarding call.
 			// In practice, the called function will often be inlined which avoids
 			// the extra indirection.
+			handlerFuncPtrType := llvm.PointerType(llvm.FunctionType(ctx.VoidType(), []llvm.Type{num.Type(), i8ptrType, i8ptrType}, false), handlerFuncPtr.Type().PointerAddressSpace())
+			handlerFuncPtr = llvm.ConstBitCast(handlerFuncPtr, handlerFuncPtrType)
 			builder.CreateCall(handlerFuncPtr, []llvm.Value{num, handlerContext, nullptr}, "")
 
 			// Replace all ptrtoint uses of the global with the interrupt constant.