go-llvm: expose intrinsic lookup and callbr builders

ir.go

@@ -118,6 +118,24 @@ func llvmValueRefs(values []Value) (*C.LLVMValueRef, C.unsigned) {
 	return pt, ptlen
 }
 
+func llvmTypeRefs(types []Type) (*C.LLVMTypeRef, C.size_t) {
+	var pt *C.LLVMTypeRef
+	ptlen := C.size_t(len(types))
+	if ptlen > 0 {
+		pt = llvmTypeRefPtr(&types[0])
+	}
+	return pt, ptlen
+}
+
+func llvmBasicBlockRefs(blocks []BasicBlock) (*C.LLVMBasicBlockRef, C.unsigned) {
+	var pt *C.LLVMBasicBlockRef
+	ptlen := C.unsigned(len(blocks))
+	if ptlen > 0 {
+		pt = llvmBasicBlockRefPtr(&blocks[0])
+	}
+	return pt, ptlen
+}
+
 func llvmMetadataRefs(mds []Metadata) (*C.LLVMMetadataRef, C.unsigned) {
 	var pt *C.LLVMMetadataRef
 	ptlen := C.unsigned(len(mds))
@@ -1075,6 +1093,19 @@ func NextFunction(v Value) (rv Value)      { rv.C = C.LLVMGetNextFunction(v.C);
 func PrevFunction(v Value) (rv Value)      { rv.C = C.LLVMGetPreviousFunction(v.C); return }
 func (v Value) EraseFromParentAsFunction() { C.LLVMDeleteFunction(v.C) }
 func (v Value) IntrinsicID() int           { return int(C.LLVMGetIntrinsicID(v.C)) }
+
+func LookupIntrinsicID(name string) uint {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	return uint(C.LLVMLookupIntrinsicID(cname, C.size_t(len(name))))
+}
+
+func GetIntrinsicDeclaration(m Module, id uint, overloadTypes []Type) (v Value) {
+	types, ntypes := llvmTypeRefs(overloadTypes)
+	v.C = C.LLVMGetIntrinsicDeclaration(m.C, C.unsigned(id), types, ntypes)
+	return
+}
+
 func (v Value) FunctionCallConv() CallConv {
 	return CallConv(C.LLVMCallConv(C.LLVMGetFunctionCallConv(v.C)))
 }
@@ -1371,6 +1402,15 @@ func (b Builder) CreateIndirectBr(addr Value, numDests int) (rv Value) {
 	rv.C = C.LLVMBuildIndirectBr(b.C, addr.C, C.unsigned(numDests))
 	return
 }
+func (b Builder) CreateCallBr(t Type, fn Value, args []Value, defaultDest BasicBlock, indirectDests []BasicBlock, name string) (rv Value) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+	dests, ndests := llvmBasicBlockRefs(indirectDests)
+	callArgs, nargs := llvmValueRefs(args)
+	rv.C = C.LLVMBuildCallBr(b.C, t.C, fn.C, defaultDest.C, dests, ndests,
+		callArgs, nargs, nil, 0, cname)
+	return
+}
 func (b Builder) CreateInvoke(t Type, fn Value, args []Value, then, catch BasicBlock, name string) (rv Value) {
 	cname := C.CString(name)
 	defer C.free(unsafe.Pointer(cname))

ir_test.go

@@ -18,6 +18,40 @@ import (
 	"testing"
 )
 
+func TestCreateCallBrIntrinsic(t *testing.T) {
+	ctx := NewContext()
+	defer ctx.Dispose()
+	mod := ctx.NewModule("callbr-intrinsic")
+	defer mod.Dispose()
+	b := ctx.NewBuilder()
+	defer b.Dispose()
+
+	intrinsicID := LookupIntrinsicID("llvm.go.defer.edge")
+	if intrinsicID == 0 {
+		t.Fatal("llvm.go.defer.edge intrinsic is unavailable")
+	}
+	deferEdge := GetIntrinsicDeclaration(mod, intrinsicID, nil)
+	fn := AddFunction(mod, "f", FunctionType(ctx.VoidType(), nil, false))
+	entry := ctx.AddBasicBlock(fn, "entry")
+	normal := ctx.AddBasicBlock(fn, "normal")
+	recover := ctx.AddBasicBlock(fn, "recover")
+
+	b.SetInsertPointAtEnd(entry)
+	b.CreateCallBr(deferEdge.GlobalValueType(), deferEdge, nil, normal, []BasicBlock{recover}, "")
+	b.SetInsertPointAtEnd(normal)
+	b.CreateRetVoid()
+	b.SetInsertPointAtEnd(recover)
+	b.CreateRetVoid()
+
+	if err := VerifyModule(mod, ReturnStatusAction); err != nil {
+		t.Fatalf("module verification failed: %v\n%s", err, mod.String())
+	}
+	if got := mod.String(); !strings.Contains(got, "callbr void @llvm.go.defer.edge()") ||
+		!strings.Contains(got, "to label %normal [label %recover]") {
+		t.Fatalf("module does not contain defer callbr:\n%s", got)
+	}
+}
+
 func TestReplaceIncomingBlock(t *testing.T) {
 	ctx := NewContext()
 	defer ctx.Dispose()