recover

c/c.go

@@ -103,6 +103,11 @@ func Qsort(base Pointer, count, elem uintptr, compar func(a, b Pointer) Int)
 
 // -----------------------------------------------------------------------------
 
+//go:linkname Atoi C.atoi
+func Atoi(s *Char) Int
+
+// -----------------------------------------------------------------------------
+
 //go:linkname Printf C.printf
 func Printf(format *Char, __llgo_va_list ...any) Int
 
@@ -171,6 +176,3 @@ func GetoptLong(argc Int, argv **Char, optstring *Char, longopts *Option, longin
 func GetoptLongOnly(argc Int, argv **Char, optstring *Char, longopts *Option, longindex *Int) Int
 
 // -----------------------------------------------------------------------------
-
-//go:linkname Atoi C.atoi
-func Atoi(s *Char) Int

cl/_testgo/defer3/in.go

@@ -20,4 +20,5 @@ func main() {
 		return
 	}
 	fail()
+	println("unreachable")
 }

cl/_testgo/defer4/in.go

@@ -0,0 +1,29 @@
+package main
+
+func f(s string) bool {
+	return len(s) > 2
+}
+
+func fail() {
+	defer println("bye")
+	defer func() {
+		if e := recover(); e != nil {
+			println("recover:", e.(string))
+		}
+	}()
+	panic("panic message")
+}
+
+func main() {
+	defer func() {
+		println("hi")
+	}()
+	if s := "hello"; f(s) {
+		defer println(s)
+	} else {
+		defer println("world")
+		return
+	}
+	fail()
+	println("reachable")
+}

cl/_testgo/defer4/out.ll

@@ -0,0 +1 @@
+;

cl/compile.go

@@ -555,7 +555,11 @@ func isPhi(i ssa.Instruction) bool {
 }
 
 func (p *context) compilePhis(b llssa.Builder, block *ssa.BasicBlock) int {
-	ret := p.fn.Block(block.Index)
+	fn := p.fn
+	ret := fn.Block(block.Index)
+	if block.Comment == "recover" { // set recover block
+		fn.SetRecover(ret)
+	}
 	b.SetBlockEx(ret, llssa.AtEnd, false)
 	if ninstr := len(block.Instrs); ninstr > 0 {
 		if isPhi(block.Instrs[0]) {

internal/runtime/z_rt.go

@@ -34,10 +34,21 @@ type Defer struct {
 	Rund unsafe.Pointer // block address after RunDefers
 }
 
+// Recover recovers a panic.
+func Recover() (ret any) {
+	ptr := excepKey.Get()
+	if ptr != nil {
+		excepKey.Set(nil)
+		ret = *(*any)(ptr)
+		c.Free(ptr)
+	}
+	return
+}
+
 // Panic panics with a value.
-func Panic(v Eface) {
+func Panic(v any) {
 	ptr := c.Malloc(unsafe.Sizeof(v))
-	*(*Eface)(ptr) = v
+	*(*any)(ptr) = v
 	excepKey.Set(ptr)
 
 	Rethrow((*Defer)(c.GoDeferData()))
@@ -45,13 +56,14 @@ func Panic(v Eface) {
 
 // Rethrow rethrows a panic.
 func Rethrow(link *Defer) {
-	if link == nil {
-		ptr := excepKey.Get()
-		TracePanic(*(*Eface)(ptr))
-		c.Free(ptr)
-		c.Exit(2)
-	} else {
-		c.Siglongjmp(link.Addr, 1)
+	if ptr := excepKey.Get(); ptr != nil {
+		if link == nil {
+			TracePanic(*(*Eface)(ptr))
+			c.Free(ptr)
+			c.Exit(2)
+		} else {
+			c.Siglongjmp(link.Addr, 1)
+		}
 	}
 }
 

ssa/decl.go

@@ -179,6 +179,7 @@ type aFunction struct {
 	blks []BasicBlock
 
 	defer_ *aDefer
+	recov  BasicBlock
 
 	params   []Type
 	freeVars Expr
@@ -329,4 +330,9 @@ func (p Function) Block(idx int) BasicBlock {
 	return p.blks[idx]
 }
 
+// SetRecover sets the recover block for the function.
+func (p Function) SetRecover(blk BasicBlock) {
+	p.recov = blk
+}
+
 // -----------------------------------------------------------------------------

ssa/eh.go

@@ -22,6 +22,7 @@ import "C"
 import (
 	"go/token"
 	"go/types"
+	"log"
 	"unsafe"
 
 	"github.com/goplus/llvm"
@@ -174,7 +175,7 @@ func (b Builder) getDefer(kind DoAction) *aDefer {
 
 		b.SetBlockEx(rethrowBlk, AtEnd, false) // rethrow
 		b.Call(b.Pkg.rtFunc("Rethrow"), link)
-		b.Unreachable() // TODO: func supports noreturn attribute
+		b.Jump(self.recov)
 
 		if kind == DeferAlways {
 			b.SetBlockEx(next, AtEnd, false)
@@ -266,16 +267,14 @@ func (b Builder) Unreachable() {
 	b.impl.CreateUnreachable()
 }
 
-/*
 // Recover emits a recover instruction.
-func (b Builder) Recover() (v Expr) {
+func (b Builder) Recover() Expr {
 	if debugInstr {
 		log.Println("Recover")
 	}
-	prog := b.Prog
-	return prog.Zero(prog.Any())
+	// TODO(xsw): recover can't be a function call in Go
+	return b.Call(b.Pkg.rtFunc("Recover"))
 }
-*/
 
 // Panic emits a panic instruction.
 func (b Builder) Panic(v Expr) {

ssa/expr.go

@@ -898,8 +898,8 @@ func (b Builder) BuiltinCall(fn string, args ...Expr) (ret Expr) {
 				}
 			}
 		}
-	//case "recover":
-	//	return b.Recover()
+	case "recover":
+		return b.Recover()
 	case "print", "println":
 		return b.PrintEx(fn == "println", args...)
 	}