feat: implement llgo.stackSave

_demo/c/stacksave/stacksave_amd64.go

@@ -0,0 +1,22 @@
+//go:build amd64
+
+package main
+
+import (
+	"unsafe"
+	_ "unsafe"
+)
+
+//go:linkname getsp llgo.stackSave
+func getsp() unsafe.Pointer
+
+//go:linkname asmFull llgo.asm
+func asmFull(instruction string, regs map[string]any) uintptr { return 0 }
+
+func main() {
+	sp := asmFull("movq %rsp, {}", nil)
+
+	if sp != uintptr(getsp()) {
+		panic("invalid stack pointer")
+	}
+}

_demo/c/stacksave/stacksave_arm64.go

@@ -0,0 +1,22 @@
+//go:build arm64
+
+package main
+
+import (
+	"unsafe"
+	_ "unsafe"
+)
+
+//go:linkname getsp llgo.stackSave
+func getsp() unsafe.Pointer
+
+//go:linkname asmFull llgo.asm
+func asmFull(instruction string, regs map[string]any) uintptr { return 0 }
+
+func main() {
+	sp := asmFull("mov {}, sp", nil)
+
+	if sp != uintptr(getsp()) {
+		panic("invalid stack pointer")
+	}
+}

cl/_testrt/stacksave/in.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"unsafe"
+	_ "unsafe"
+)
+
+//go:linkname getsp llgo.stackSave
+func getsp() unsafe.Pointer
+
+func main() {
+	sp := getsp()
+	println(sp)
+}

cl/_testrt/stacksave/out.ll

@@ -0,0 +1,34 @@
+; ModuleID = 'github.com/goplus/llgo/cl/_testrt/stacksave'
+source_filename = "github.com/goplus/llgo/cl/_testrt/stacksave"
+
+@"github.com/goplus/llgo/cl/_testrt/stacksave.init$guard" = global i1 false, align 1
+
+define void @"github.com/goplus/llgo/cl/_testrt/stacksave.init"() {
+_llgo_0:
+  %0 = load i1, ptr @"github.com/goplus/llgo/cl/_testrt/stacksave.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"github.com/goplus/llgo/cl/_testrt/stacksave.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define void @"github.com/goplus/llgo/cl/_testrt/stacksave.main"() {
+_llgo_0:
+  %0 = call ptr @llvm.stacksave()
+  call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintPointer"(ptr %0)
+  call void @"github.com/goplus/llgo/runtime/internal/runtime.PrintByte"(i8 10)
+  ret void
+}
+
+; Function Attrs: nocallback nofree nosync nounwind willreturn
+declare ptr @llvm.stacksave() #0
+
+declare void @"github.com/goplus/llgo/runtime/internal/runtime.PrintPointer"(ptr)
+
+declare void @"github.com/goplus/llgo/runtime/internal/runtime.PrintByte"(i8)
+
+attributes #0 = { nocallback nofree nosync nounwind willreturn }

cl/import.go

@@ -503,7 +503,8 @@ const (
 	llgoCgoCheckPointer = llgoCgoBase + 0x6
 	llgoCgoCgocall      = llgoCgoBase + 0x7
 
-	llgoAsm = llgoInstrBase + 0x40
+	llgoAsm       = llgoInstrBase + 0x40
+	llgoStackSave = llgoInstrBase + 0x41
 
 	llgoAtomicOpLast = llgoAtomicOpBase + int(llssa.OpUMin)
 )

cl/instr.go

@@ -425,7 +425,8 @@ var llgoInstrs = map[string]int{
 	"_cgoCheckPointer":     llgoCgoCheckPointer,
 	"_cgo_runtime_cgocall": llgoCgoCgocall,
 
-	"asm": llgoAsm,
+	"asm":       llgoAsm,
+	"stackSave": llgoStackSave,
 }
 
 // funcOf returns a function by name and set ftype = goFunc, cFunc, etc.
@@ -601,6 +602,8 @@ func (p *context) call(b llssa.Builder, act llssa.DoAction, call *ssa.CallCommon
 			ret = p.sigsetjmp(b, args)
 		case llgoSiglongjmp:
 			p.siglongjmp(b, args)
+		case llgoStackSave:
+			ret = b.StackSave()
 		case llgoSigjmpbuf: // func sigjmpbuf()
 			ret = b.AllocaSigjmpBuf()
 		case llgoDeferData: // func deferData() *Defer

ssa/eh.go

@@ -91,13 +91,29 @@ func (p Program) tySiglongjmp() *types.Signature {
 	return p.sigljmpTy
 }
 
+// func() unsafe.Pointer
+func (p Program) tyStacksave() *types.Signature {
+	if p.stackSaveTy == nil {
+		paramPtr := types.NewParam(token.NoPos, nil, "", p.VoidPtr().raw.Type)
+		params := types.NewTuple(paramPtr)
+		p.stackSaveTy = types.NewSignatureType(nil, nil, nil, nil, params, false)
+	}
+	return p.stackSaveTy
+}
+
 func (b Builder) AllocaSigjmpBuf() Expr {
 	prog := b.Prog
 	n := unsafe.Sizeof(sigjmpbuf{})
 	size := prog.IntVal(uint64(n), prog.Uintptr())
 	return b.Alloca(size)
 }
 
+// declare ptr @llvm.stacksave.p0()
+func (b Builder) StackSave() Expr {
+	fn := b.Pkg.cFunc("llvm.stacksave", b.Prog.tyStacksave())
+	return b.InlineCall(fn)
+}
+
 func (b Builder) Sigsetjmp(jb, savemask Expr) Expr {
 	if b.Prog.target.GOARCH == "wasm" {
 		return b.Setjmp(jb)

ssa/package.go

@@ -195,6 +195,7 @@ type aProgram struct {
 	mallocTy       *types.Signature
 	freeTy         *types.Signature
 	memsetInlineTy *types.Signature
+	stackSaveTy    *types.Signature
 
 	createKeyTy *types.Signature
 	getSpecTy   *types.Signature