compiler: support all kinds of deferred builtins

This change extends defer support to all supported builitin functions.
Not all of them make sense (such as len, cap, real, imag, etc) but this
change for example adds support for `defer(delete(m, key))` which is
used in the Go 1.15 encoding/json package.

Author: aykevl

compiler/channel.go

@@ -79,8 +79,7 @@ func (b *builder) createChanRecv(unop *ssa.UnOp) llvm.Value {
 }
 
 // createChanClose closes the given channel.
-func (b *builder) createChanClose(param ssa.Value) {
-	ch := b.getValue(param)
+func (b *builder) createChanClose(ch llvm.Value) {
 	b.createRuntimeCall("chanClose", []llvm.Value{ch}, "")
 }
 

compiler/compiler.go

@@ -130,7 +130,9 @@ func newBuilder(c *compilerContext, irbuilder llvm.Builder, f *ir.Function) *bui
 }
 
 type deferBuiltin struct {
-	funcName string
+	callName string
+	pos      token.Pos
+	argTypes []types.Type
 	callback int
 }
 
@@ -1196,11 +1198,11 @@ func (b *builder) createInstruction(instr ssa.Instruction) {
 
 // createBuiltin lowers a builtin Go function (append, close, delete, etc.) to
 // LLVM IR. It uses runtime calls for some builtins.
-func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos) (llvm.Value, error) {
+func (b *builder) createBuiltin(argTypes []types.Type, argValues []llvm.Value, callName string, pos token.Pos) (llvm.Value, error) {
 	switch callName {
 	case "append":
-		src := b.getValue(args[0])
-		elems := b.getValue(args[1])
+		src := argValues[0]
+		elems := argValues[1]
 		srcBuf := b.CreateExtractValue(src, 0, "append.srcBuf")
 		srcPtr := b.CreateBitCast(srcBuf, b.i8ptrType, "append.srcPtr")
 		srcLen := b.CreateExtractValue(src, 1, "append.srcLen")
@@ -1221,9 +1223,9 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		newSlice = b.CreateInsertValue(newSlice, newCap, 2, "")
 		return newSlice, nil
 	case "cap":
-		value := b.getValue(args[0])
+		value := argValues[0]
 		var llvmCap llvm.Value
-		switch args[0].Type().(type) {
+		switch argTypes[0].(type) {
 		case *types.Chan:
 			llvmCap = b.createRuntimeCall("chanCap", []llvm.Value{value}, "cap")
 		case *types.Slice:
@@ -1236,12 +1238,12 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		}
 		return llvmCap, nil
 	case "close":
-		b.createChanClose(args[0])
+		b.createChanClose(argValues[0])
 		return llvm.Value{}, nil
 	case "complex":
-		r := b.getValue(args[0])
-		i := b.getValue(args[1])
-		t := args[0].Type().Underlying().(*types.Basic)
+		r := argValues[0]
+		i := argValues[1]
+		t := argTypes[0].Underlying().(*types.Basic)
 		var cplx llvm.Value
 		switch t.Kind() {
 		case types.Float32:
@@ -1255,8 +1257,8 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		cplx = b.CreateInsertValue(cplx, i, 1, "")
 		return cplx, nil
 	case "copy":
-		dst := b.getValue(args[0])
-		src := b.getValue(args[1])
+		dst := argValues[0]
+		src := argValues[1]
 		dstLen := b.CreateExtractValue(dst, 1, "copy.dstLen")
 		srcLen := b.CreateExtractValue(src, 1, "copy.srcLen")
 		dstBuf := b.CreateExtractValue(dst, 0, "copy.dstArray")
@@ -1267,16 +1269,16 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		elemSize := llvm.ConstInt(b.uintptrType, b.targetData.TypeAllocSize(elemType), false)
 		return b.createRuntimeCall("sliceCopy", []llvm.Value{dstBuf, srcBuf, dstLen, srcLen, elemSize}, "copy.n"), nil
 	case "delete":
-		m := b.getValue(args[0])
-		key := b.getValue(args[1])
-		return llvm.Value{}, b.createMapDelete(args[1].Type(), m, key, pos)
+		m := argValues[0]
+		key := argValues[1]
+		return llvm.Value{}, b.createMapDelete(argTypes[1], m, key, pos)
 	case "imag":
-		cplx := b.getValue(args[0])
+		cplx := argValues[0]
 		return b.CreateExtractValue(cplx, 1, "imag"), nil
 	case "len":
-		value := b.getValue(args[0])
+		value := argValues[0]
 		var llvmLen llvm.Value
-		switch args[0].Type().Underlying().(type) {
+		switch argTypes[0].Underlying().(type) {
 		case *types.Basic, *types.Slice:
 			// string or slice
 			llvmLen = b.CreateExtractValue(value, 1, "len")
@@ -1292,12 +1294,11 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		}
 		return llvmLen, nil
 	case "print", "println":
-		for i, arg := range args {
+		for i, value := range argValues {
 			if i >= 1 && callName == "println" {
 				b.createRuntimeCall("printspace", nil, "")
 			}
-			value := b.getValue(arg)
-			typ := arg.Type().Underlying()
+			typ := argTypes[i].Underlying()
 			switch typ := typ.(type) {
 			case *types.Basic:
 				switch typ.Kind() {
@@ -1349,13 +1350,13 @@ func (b *builder) createBuiltin(args []ssa.Value, callName string, pos token.Pos
 		}
 		return llvm.Value{}, nil // print() or println() returns void
 	case "real":
-		cplx := b.getValue(args[0])
+		cplx := argValues[0]
 		return b.CreateExtractValue(cplx, 0, "real"), nil
 	case "recover":
 		return b.createRuntimeCall("_recover", nil, ""), nil
 	case "ssa:wrapnilchk":
 		// TODO: do an actual nil check?
-		return b.getValue(args[0]), nil
+		return argValues[0], nil
 	default:
 		return llvm.Value{}, b.makeError(pos, "todo: builtin: "+callName)
 	}
@@ -1432,7 +1433,13 @@ func (b *builder) createFunctionCall(instr *ssa.CallCommon) (llvm.Value, error)
 		exported = targetFunc.IsExported()
 	} else if call, ok := instr.Value.(*ssa.Builtin); ok {
 		// Builtin function (append, close, delete, etc.).)
-		return b.createBuiltin(instr.Args, call.Name(), instr.Pos())
+		var argTypes []types.Type
+		var argValues []llvm.Value
+		for _, arg := range instr.Args {
+			argTypes = append(argTypes, arg.Type())
+			argValues = append(argValues, b.getValue(arg))
+		}
+		return b.createBuiltin(argTypes, argValues, call.Name(), instr.Pos())
 	} else {
 		// Function pointer.
 		value := b.getValue(instr.Value)

compiler/defer.go

@@ -155,19 +155,19 @@ func (b *builder) createDefer(instr *ssa.Defer) {
 		valueTypes = append(valueTypes, context.Type())
 
 	} else if builtin, ok := instr.Call.Value.(*ssa.Builtin); ok {
-		var funcName string
-		switch builtin.Name() {
-		case "close":
-			funcName = "chanClose"
-		default:
-			b.addError(instr.Pos(), "todo: Implement defer for "+builtin.Name())
-			return
+		var argTypes []types.Type
+		var argValues []llvm.Value
+		for _, arg := range instr.Call.Args {
+			argTypes = append(argTypes, arg.Type())
+			argValues = append(argValues, b.getValue(arg))
 		}
 
 		if _, ok := b.deferBuiltinFuncs[instr.Call.Value]; !ok {
 			b.deferBuiltinFuncs[instr.Call.Value] = deferBuiltin{
-				funcName,
-				len(b.allDeferFuncs),
+				callName: builtin.Name(),
+				pos:      builtin.Pos(),
+				argTypes: argTypes,
+				callback: len(b.allDeferFuncs),
 			}
 			b.allDeferFuncs = append(b.allDeferFuncs, instr.Call.Value)
 		}
@@ -176,10 +176,9 @@ func (b *builder) createDefer(instr *ssa.Defer) {
 		// Collect all values to be put in the struct (starting with
 		// runtime._defer fields).
 		values = []llvm.Value{callback, next}
-		for _, param := range instr.Call.Args {
-			llvmParam := b.getValue(param)
-			values = append(values, llvmParam)
-			valueTypes = append(valueTypes, llvmParam.Type())
+		for _, param := range argValues {
+			values = append(values, param)
+			valueTypes = append(valueTypes, param.Type())
 		}
 
 	} else {
@@ -426,15 +425,18 @@ func (b *builder) createRunDefers() {
 			deferFramePtr := b.CreateBitCast(deferData, llvm.PointerType(deferFrameType, 0), "deferFrame")
 
 			// Extract the params from the struct.
-			var forwardParams []llvm.Value
+			var argValues []llvm.Value
 			zero := llvm.ConstInt(b.ctx.Int32Type(), 0, false)
 			for i := 0; i < params.Len(); i++ {
 				gep := b.CreateInBoundsGEP(deferFramePtr, []llvm.Value{zero, llvm.ConstInt(b.ctx.Int32Type(), uint64(i+2), false)}, "gep")
 				forwardParam := b.CreateLoad(gep, "param")
-				forwardParams = append(forwardParams, forwardParam)
+				argValues = append(argValues, forwardParam)
 			}
 
-			b.createRuntimeCall(db.funcName, forwardParams, "")
+			_, err := b.createBuiltin(db.argTypes, argValues, db.callName, db.pos)
+			if err != nil {
+				b.diagnostics = append(b.diagnostics, err)
+			}
 		default:
 			panic("unknown deferred function type")
 		}

testdata/calls.go

@@ -72,7 +72,8 @@ func main() {
 	regression1033()
 
 	//Test deferred builtins
-	testDeferBuiltin()
+	testDeferBuiltinClose()
+	testDeferBuiltinDelete()
 }
 
 func runFunc(f func(int), arg int) {
@@ -121,13 +122,30 @@ func testMultiFuncVar() {
 	defer f(1)
 }
 
-func testDeferBuiltin() {
+func testDeferBuiltinClose() {
 	i := make(chan int)
-	defer close(i)
+	func() {
+		defer close(i)
+	}()
+	if n, ok := <-i; n != 0 || ok {
+		println("expected to read 0 from closed channel")
+	}
 }
 
-type dumb struct {
+func testDeferBuiltinDelete() {
+	m := map[int]int{3: 30, 5: 50}
+	func() {
+		defer delete(m, 3)
+		if m[3] != 30 {
+			println("expected m[3] to be 30")
+		}
+	}()
+	if m[3] != 0 {
+		println("expected m[3] to be 0")
+	}
+}
 
+type dumb struct {
 }
 
 func (*dumb) Value(key interface{}) interface{} {
@@ -144,17 +162,17 @@ func exportedDefer() {
 }
 
 func deferFunc() (int, func(int)) {
-	return 0, func(i int){println("...extracted defer func ", i)}
+	return 0, func(i int) { println("...extracted defer func ", i) }
 }
 
 func multiFuncDefer() func(int) {
 	i := 0
 
 	if i > 0 {
-		return func(i int){println("Should not have gotten here. i = ", i)}
+		return func(i int) { println("Should not have gotten here. i = ", i) }
 	}
 
-	return func(i int){println("Called the correct function. i = ", i)}
+	return func(i int) { println("Called the correct function. i = ", i) }
 }
 
 func testBound(f func() string) {