Issue 11383043: code review 11383043: cmd/8g: Make clearfat non-interleaved with pointer calc...

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Issue 11383043: code review 11383043: cmd/8g: Make clearfat non-interleaved with pointer calc... (Closed)

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Created:
10 years, 9 months ago by DMorsing

Modified:
10 years, 9 months ago

Reviewers:
rsc

CC:
golang-dev, rsc

Visibility:
Public.

Description

cmd/8g: Make clearfat non-interleaved with pointer calculations. clearfat (used to zero initialize structures) will use AX for x86 block ops. If we write to AX while calculating the dest pointer, we will fill the structure with incorrect values. Since 64-bit arithmetic uses AX to synthesize a 64-bit register, getting an adress by indexing with 64-bit ops can clobber the register. Fixes issue 5820.

Patch Set 1 #

Patch Set 2 : diff -r f3170d09181d https://code.google.com/p/go/ #

Patch Set 3 : diff -r f3170d09181d https://code.google.com/p/go/ #

Patch Set 4 : diff -r 28a2612c7ff1 https://code.google.com/p/go/ #

Created: 10 years, 9 months ago

Download [raw] [tar.bz2]

		Unified diffs	Side-by-side diffs	Delta from patch set	Stats (+19 lines, -1 line)			Patch
	M	src/cmd/8g/ggen.c	View	1	1 chunk	+1 line, -1 line	0 comments	Download
	A	test/fixedbugs/issue5820.go	View	1	1 chunk	+18 lines, -0 lines	0 comments	Download

Messages

Total messages: 3

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DMorsing

Hello golang-dev@googlegroups.com, I'd like you to review this change to https://code.google.com/p/go/

10 years, 9 months ago (2013-07-16 20:53:37 UTC) #1

DMorsing

10 years, 9 months ago (2013-07-17 09:04:38 UTC) #3

*** Submitted as https://code.google.com/p/go/source/detail?r=dc24634de6c5 ***

cmd/8g: Make clearfat non-interleaved with pointer calculations.

clearfat (used to zero initialize structures) will use AX for x86 block ops. If
we write to AX while calculating the dest pointer, we will fill the structure
with incorrect values.
Since 64-bit arithmetic uses AX to synthesize a 64-bit register, getting an
adress by indexing with 64-bit ops can clobber the register.

Fixes issue 5820.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/11383043

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