From 95a7aeb19222c24f73133a4a64ee263ac39a80a2 Mon Sep 17 00:00:00 2001
From: Josh Bleecher Snyder <josharian@gmail.com>
Date: Fri, 20 Jun 2014 16:52:48 -0700
Subject: [PATCH] go.tools/cmd/vet: don't panic on commented-out asm

Really two fixes: Don't panic on bad instructions and don't complain about commented out instructions.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/110070044
---
 cmd/vet/asmdecl.go      | 5 ++++-
 cmd/vet/testdata/asm1.s | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/cmd/vet/asmdecl.go b/cmd/vet/asmdecl.go
index c32ed993..37259f47 100644
--- a/cmd/vet/asmdecl.go
+++ b/cmd/vet/asmdecl.go
@@ -423,7 +423,10 @@ func (f *File) asmParseDecl(decl *ast.FuncDecl) map[string]*asmFunc {
 func asmCheckVar(badf func(string, ...interface{}), fn *asmFunc, line, expr string, off int, v *asmVar) {
 	m := asmOpcode.FindStringSubmatch(line)
 	if m == nil {
-		badf("cannot find assembly opcode")
+		if !strings.HasPrefix(strings.TrimSpace(line), "//") {
+			badf("cannot find assembly opcode")
+		}
+		return
 	}
 
 	// Determine operand sizes from instruction.
diff --git a/cmd/vet/testdata/asm1.s b/cmd/vet/testdata/asm1.s
index 8cd9eeab..071ce3c5 100644
--- a/cmd/vet/testdata/asm1.s
+++ b/cmd/vet/testdata/asm1.s
@@ -7,6 +7,7 @@
 
 TEXT ·arg1(SB),0,$0-2
 	MOVB	x+0(FP), AX
+	// MOVB x+0(FP), AX // commented out instructions used to panic
 	MOVB	y+1(FP), BX
 	MOVW	x+0(FP), AX // ERROR "\[amd64\] invalid MOVW of x\+0\(FP\); int8 is 1-byte value"
 	MOVW	y+1(FP), AX // ERROR "invalid MOVW of y\+1\(FP\); uint8 is 1-byte value"