From: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Date: Thu, 22 Dec 2022 20:37:43 +0000 (+0700)
Subject: cmd/compile: emit ODCL node for autotmp during RewriteNonNameCall
X-Git-Tag: go1.21rc1~1079
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=e539461e34b1c5163220f9910b2c0360fb9f21e4;p=gostls13.git

cmd/compile: emit ODCL node for autotmp during RewriteNonNameCall

For f()() call, the compiler rewrite it roughly to:

	autotmp := f()
	autotmp()

However, if f() were inlined, escape analysis will confuse about the
lifetime of autotmp, leading to bad escaping decision.

This CL fixes this issue by rewriting f()() to:

	var autotmp
	autotmp = f()
	autotmp()

This problem also happens with Unified IR, until CL 421821 land.

Fixes #57434

Change-Id: I159a7e4c93bbc172f0eae60e7d40fc64ba70b236
Reviewed-on: https://go-review.googlesource.com/c/go/+/459295
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Cuong Manh Le <cuong.manhle.vn@gmail.com>
---

diff --git a/src/cmd/compile/internal/typecheck/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
index 29bc61db60..e160265d49 100644
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -889,7 +889,7 @@ func RewriteNonNameCall(n *ir.CallExpr) {
 
 	tmp := Temp((*np).Type())
 	as := ir.NewAssignStmt(base.Pos, tmp, *np)
-	as.Def = true
+	as.PtrInit().Append(Stmt(ir.NewDecl(n.Pos(), ir.ODCL, tmp)))
 	*np = tmp
 
 	if static {