cl: c.Func (llgo.funcAddr); demo: cppintf (how to use c++ interface)

_demo/cppintf/cppintf.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"github.com/goplus/llgo/_demo/cppintf/foo"
+	"github.com/goplus/llgo/c"
+)
+
+type Bar struct {
+	foo.Callback
+	a int
+	b float64
+}
+
+func NewBar(a int, b float64) *Bar {
+	return &Bar{
+		Callback: foo.Callback{
+			Vptr: &foo.CallbackVtbl{
+				ValA: c.Func((*Bar).getA),
+				ValB: c.Func((*Bar).getB),
+			},
+		},
+		a: a, b: b,
+	}
+}
+
+func (p *Bar) getA() int {
+	return p.a
+}
+
+func (p *Bar) getB() float64 {
+	return p.b
+}
+
+func main() {
+	bar := NewBar(1, 2.0)
+	foo.F(&bar.Callback)
+}

_demo/cppintf/foo/bar/bar.cpp

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#define interface struct
+
+interface ICallback {
+	virtual int valA() = 0;
+	virtual double valB() = 0;
+};
+
+extern "C" void f(ICallback* cb) {
+	printf("Hello %d, %lf!\n", cb->valA(), cb->valB());
+}

_demo/cppintf/foo/foo.go

@@ -0,0 +1,22 @@
+package foo
+
+import (
+	"unsafe"
+)
+
+const (
+	LLGoFiles   = "bar/bar.cpp"
+	LLGoPackage = "link"
+)
+
+type Callback struct {
+	Vptr *CallbackVtbl
+}
+
+type CallbackVtbl struct {
+	ValA unsafe.Pointer
+	ValB unsafe.Pointer
+}
+
+//go:linkname F C.f
+func F(cb *Callback)

c/c.go

@@ -48,6 +48,9 @@ type integer interface {
 //go:linkname Str llgo.cstr
 func Str(string) *Char
 
+//go:linkname Func llgo.funcAddr
+func Func(any) Pointer
+
 // llgo:link Advance llgo.advance
 func Advance[PtrT any, I integer](ptr PtrT, offset I) PtrT { return ptr }
 

cl/_testlibc/complex/in.go

@@ -1,10 +1,12 @@
 package main
 
 import (
+	"github.com/goplus/llgo/c"
 	"github.com/goplus/llgo/c/math/cmplx"
 )
 
-func f(c, z complex64) {
+func f(c, z complex64, addr c.Pointer) {
+	println("addr:", addr)
 	println("abs(3+4i):", cmplx.Absf(c))
 	println("real(3+4i):", real(z))
 	println("imag(3+4i):", imag(z))
@@ -14,6 +16,6 @@ func main() {
 	re := float32(3.0)
 	im := float32(4.0)
 	z := complex64(3 + 4i)
-	c := complex(re, im)
+	x := complex(re, im)
-	f(c, z)
+	f(x, z, c.Func(f))
 }

cl/_testlibc/complex/out.ll

@@ -4,49 +4,60 @@ source_filename = "main"
 %"github.com/goplus/llgo/internal/runtime.String" = type { ptr, i64 }
 
 @"main.init$guard" = global i1 false, align 1
-@0 = private unnamed_addr constant [10 x i8] c"abs(3+4i):", align 1
+@0 = private unnamed_addr constant [5 x i8] c"addr:", align 1
-@1 = private unnamed_addr constant [11 x i8] c"real(3+4i):", align 1
+@1 = private unnamed_addr constant [10 x i8] c"abs(3+4i):", align 1
-@2 = private unnamed_addr constant [11 x i8] c"imag(3+4i):", align 1
+@2 = private unnamed_addr constant [11 x i8] c"real(3+4i):", align 1
+@3 = private unnamed_addr constant [11 x i8] c"imag(3+4i):", align 1
 @__llgo_argc = global i32 0, align 4
 @__llgo_argv = global ptr null, align 8
 
-define void @main.f({ float, float } %0, { float, float } %1) {
+define void @main.f({ float, float } %0, { float, float } %1, ptr %2) {
 _llgo_0:
-  %2 = call float @cabsf({ float, float } %0)
   %3 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
   %4 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %3, i32 0, i32 0
   store ptr @0, ptr %4, align 8
   %5 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %3, i32 0, i32 1
-  store i64 10, ptr %5, align 4
+  store i64 5, ptr %5, align 4
   %6 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %3, align 8
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %6)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
-  %7 = fpext float %2 to double
+  call void @"github.com/goplus/llgo/internal/runtime.PrintPointer"(ptr %2)
-  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %7)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
-  %8 = extractvalue { float, float } %1, 0
+  %7 = call float @cabsf({ float, float } %0)
-  %9 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %8 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %9, i32 0, i32 0
+  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %8, i32 0, i32 0
-  store ptr @1, ptr %10, align 8
+  store ptr @1, ptr %9, align 8
-  %11 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %9, i32 0, i32 1
+  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %8, i32 0, i32 1
-  store i64 11, ptr %11, align 4
+  store i64 10, ptr %10, align 4
-  %12 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %9, align 8
+  %11 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %8, align 8
-  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %12)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %11)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
-  %13 = fpext float %8 to double
+  %12 = fpext float %7 to double
-  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %13)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %12)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
-  %14 = extractvalue { float, float } %1, 1
+  %13 = extractvalue { float, float } %1, 0
-  %15 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %14 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
-  %16 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %15, i32 0, i32 0
+  %15 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %14, i32 0, i32 0
-  store ptr @2, ptr %16, align 8
+  store ptr @2, ptr %15, align 8
-  %17 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %15, i32 0, i32 1
+  %16 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %14, i32 0, i32 1
-  store i64 11, ptr %17, align 4
+  store i64 11, ptr %16, align 4
-  %18 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %15, align 8
+  %17 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %14, align 8
-  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %18)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %17)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
-  %19 = fpext float %14 to double
+  %18 = fpext float %13 to double
-  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %19)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %18)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  %19 = extractvalue { float, float } %1, 1
+  %20 = alloca %"github.com/goplus/llgo/internal/runtime.String", align 8
+  %21 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %20, i32 0, i32 0
+  store ptr @3, ptr %21, align 8
+  %22 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.String", ptr %20, i32 0, i32 1
+  store i64 11, ptr %22, align 4
+  %23 = load %"github.com/goplus/llgo/internal/runtime.String", ptr %20, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %23)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 32)
+  %24 = fpext float %19 to double
+  call void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double %24)
   call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
   ret void
 }
@@ -76,16 +87,18 @@ _llgo_0:
   %4 = getelementptr inbounds { float, float }, ptr %2, i32 0, i32 1
   store float 4.000000e+00, ptr %4, align 4
   %5 = load { float, float }, ptr %2, align 4
-  call void @main.f({ float, float } %5, { float, float } { float 3.000000e+00, float 4.000000e+00 })
+  call void @main.f({ float, float } %5, { float, float } { float 3.000000e+00, float 4.000000e+00 }, ptr @main.f)
   ret i32 0
 }
 
-declare float @cabsf({ float, float })
-
 declare void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String")
 
 declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
 
+declare void @"github.com/goplus/llgo/internal/runtime.PrintPointer"(ptr)
+
+declare float @cabsf({ float, float })
+
 declare void @"github.com/goplus/llgo/internal/runtime.PrintFloat"(double)
 
 declare void @"github.com/goplus/llgo/internal/runtime.init"()

cl/builtin_test.go

@@ -139,6 +139,7 @@ func TestErrBuiltin(t *testing.T) {
 	test("allocaCStr", func(ctx *context) { ctx.allocaCStr(nil, nil) })
 	test("string", func(ctx *context) { ctx.string(nil, nil) })
 	test("stringData", func(ctx *context) { ctx.stringData(nil, nil) })
+	test("funcAddr", func(ctx *context) { ctx.funcAddr(nil, nil) })
 	test("sigsetjmp", func(ctx *context) { ctx.sigsetjmp(nil, nil) })
 	test("siglongjmp", func(ctx *context) { ctx.siglongjmp(nil, nil) })
 	test("cstr(NoArgs)", func(ctx *context) { cstr(nil, nil) })

cl/compile.go

@@ -524,12 +524,19 @@ func (p *context) compileInstrOrValue(b llssa.Builder, iv instrOrValue, asValue
 		ret = b.Slice(x, low, high, max)
 	case *ssa.MakeInterface:
 		if refs := *v.Referrers(); len(refs) == 1 {
-			if ref, ok := refs[0].(*ssa.Store); ok {
+			switch ref := refs[0].(type) {
+			case *ssa.Store:
 				if va, ok := ref.Addr.(*ssa.IndexAddr); ok {
 					if _, ok = p.isVArgs(va.X); ok { // varargs: this is a varargs store
 						return
 					}
 				}
+			case *ssa.Call:
+				if fn, ok := ref.Call.Value.(*ssa.Function); ok {
+					if _, _, ftype := p.funcOf(fn); ftype == llgoFuncAddr { // llgo.funcAddr
+						return
+					}
+				}
 			}
 		}
 		t := p.prog.Type(v.Type(), llssa.InGo)

cl/import.go

@@ -384,6 +384,7 @@ const (
 	llgoDeferData   = llgoInstrBase + 6
 	llgoStringData  = llgoInstrBase + 7
 	llgoString      = llgoInstrBase + 8
+	llgoFuncAddr    = llgoInstrBase + 9
 
 	llgoSigjmpbuf  = llgoInstrBase + 0xa
 	llgoSigsetjmp  = llgoInstrBase + 0xb

cl/instr.go

@@ -94,6 +94,20 @@ func (p *context) stringData(b llssa.Builder, args []ssa.Value) (ret llssa.Expr)
 	panic("stringData(s string): invalid arguments")
 }
 
+// func funcAddr(fn any) unsafe.Pointer
+func (p *context) funcAddr(b llssa.Builder, args []ssa.Value) llssa.Expr {
+	if len(args) == 1 {
+		if fn, ok := args[0].(*ssa.MakeInterface); ok {
+			if fnDecl, ok := fn.X.(*ssa.Function); ok {
+				if aFn, _, _ := p.compileFunction(fnDecl); aFn != nil {
+					return aFn.Expr
+				}
+			}
+		}
+	}
+	panic("funcAddr(<func>): invalid arguments")
+}
+
 func (p *context) sigsetjmp(b llssa.Builder, args []ssa.Value) (ret llssa.Expr) {
 	if len(args) == 2 {
 		jb := p.compileValue(b, args[0])
@@ -160,6 +174,7 @@ var llgoInstrs = map[string]int{
 	"allocaCStr":  llgoAllocaCStr,
 	"string":      llgoString,
 	"stringData":  llgoStringData,
+	"funcAddr":    llgoFuncAddr,
 	"pyList":      llgoPyList,
 	"sigjmpbuf":   llgoSigjmpbuf,
 	"sigsetjmp":   llgoSigsetjmp,
@@ -327,6 +342,8 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			ret = b.AllocaSigjmpBuf()
 		case llgoDeferData: // func deferData() *Defer
 			ret = b.DeferData()
+		case llgoFuncAddr:
+			ret = p.funcAddr(b, args)
 		case llgoUnreachable: // func unreachable()
 			b.Unreachable()
 		default: