languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-10-14 03:43:28 +00:00
Code Issues Packages Projects Releases Wiki Activity

cmd/6g, cmd/8g: fix, test byte-sized magic multiply

Browse source 
Credit to Rémy for finding and writing test case.

Fixes #8325.

LGTM=r
R=golang-codereviews, r
CC=dave, golang-codereviews, iant, remyoudompheng
https://golang.org/cl/124950043
This commit is contained in:
Russ Cox 2014-08-11 15:24:36 -04:00
parent eae9fee3bf
commit 5b63ce4e19
5 changed files with 43 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
src/cmd/6g/ggen.c
View file

@ -943,7 +943,7 @@ cgen_hmul(Node *nl, Node *nr, Node *res)
if(t->width == 1) {
// byte multiply behaves differently.
nodreg(&ax, t, D_AH);
nodreg(&dx, t, D_DL);
nodreg(&dx, t, D_DX);
gmove(&ax, &dx);
}
nodreg(&dx, t, D_DX);

5
src/cmd/6g/peep.c
View file

@ -838,6 +838,11 @@ copyu(Prog *p, Adr *v, Adr *s)
static int
copyas(Adr *a, Adr *v)
{
if(D_AL <= a->type && a->type <= D_R15B)
fatal("use of byte register");
if(D_AL <= v->type && v->type <= D_R15B)
fatal("use of byte register");
if(a->type != v->type)
return 0;
if(regtyp(v))

2
src/cmd/8g/ggen.c
View file

@ -991,7 +991,7 @@ cgen_hmul(Node *nl, Node *nr, Node *res)
if(t->width == 1) {
// byte multiply behaves differently.
nodreg(&ax, t, D_AH);
nodreg(&dx, t, D_DL);
nodreg(&dx, t, D_DX);
gmove(&ax, &dx);
}
nodreg(&dx, t, D_DX);

5
src/cmd/8g/peep.c
View file

@ -636,6 +636,11 @@ copyu(Prog *p, Adr *v, Adr *s)
static int
copyas(Adr *a, Adr *v)
{
if(D_AL <= a->type && a->type <= D_R15B)
fatal("use of byte register");
if(D_AL <= v->type && v->type <= D_R15B)
fatal("use of byte register");
if(a->type != v->type)
return 0;
if(regtyp(v))

31
test/fixedbugs/issue8325.go Normal file
View file

@ -0,0 +1,31 @@
// run
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Issue 8325: corrupted byte operations during optimization
// pass.
package main
const alphanum = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
func main() {
var bytes = []byte{10, 20, 30, 40, 50}
for i, b := range bytes {
bytes[i] = alphanum[b%byte(len(alphanum))]
}
for _, b := range bytes {
switch {
case '0' <= b && b <= '9',
'A' <= b && b <= 'Z':
default:
println("found a bad character", string(b))
panic("BUG")
}
}
}