From 80a153dd5189d8bbc9d090f0ef0691c224d8b0a1 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Tue, 10 Sep 2013 14:53:41 -0400
Subject: [PATCH] cmd/6l, cmd/8l: fix MOVL MOVQ optab

The entry for LEAL/LEAQ in these optabs was listed as having
two data bytes in the y array. In fact they had and expect no data
bytes. However, the general loop expects to be able to look at at
least one data byte, to make sure it is not 0x0f. So give them each
a single data byte set to 0 (not 0x0f).

Since the MOV instructions have the largest optab cases, this
requires growing the size of the data array.

Clang found this bug because the general o->op[z] == 0x0f
test was using z == 22, which was out of bounds.

In practice the next byte in memory was probably not 0x0f
so it wasn't truly broken. But might as well be clean.

Update #5764

R=ken2
CC=golang-dev
https://golang.org/cl/13241050
---
 src/cmd/6l/l.h     |  2 +-
 src/cmd/6l/optab.c |  6 +++---
 src/cmd/8l/l.h     |  2 +-
 src/cmd/8l/optab.c | 17 ++++++++++++++---
 4 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h
index 265a6947e8..ecab867e43 100644
--- a/src/cmd/6l/l.h
+++ b/src/cmd/6l/l.h
@@ -193,7 +193,7 @@ struct	Optab
 	short	as;
 	uchar*	ytab;
 	uchar	prefix;
-	uchar	op[22];
+	uchar	op[23];
 };
 struct	Movtab
 {
diff --git a/src/cmd/6l/optab.c b/src/cmd/6l/optab.c
index c354967b98..46603ad451 100644
--- a/src/cmd/6l/optab.c
+++ b/src/cmd/6l/optab.c
@@ -913,7 +913,7 @@ Optab optab[] =
 	{ AMOVHLPS,	yxr,	Pm, 0x12 },
 	{ AMOVHPD,	yxmov,	Pe, 0x16,0x17 },
 	{ AMOVHPS,	yxmov,	Pm, 0x16,0x17 },
-	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0xb8,0xc7,(00),0x6e,0x7e,Pe,0x6e,Pe,0x7e },
+	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0xb8,0xc7,(00),0x6e,0x7e,Pe,0x6e,Pe,0x7e,0 },
 	{ AMOVLHPS,	yxr,	Pm, 0x16 },
 	{ AMOVLPD,	yxmov,	Pe, 0x12,0x13 },
 	{ AMOVLPS,	yxmov,	Pm, 0x12,0x13 },
@@ -925,7 +925,7 @@ Optab optab[] =
 	{ AMOVNTPD,	yxr_ml,	Pe, 0x2b },
 	{ AMOVNTPS,	yxr_ml,	Pm, 0x2b },
 	{ AMOVNTQ,	ymr_ml,	Pm, 0xe7 },
-	{ AMOVQ,	ymovq,	Pw, 0x89, 0x8b, 0x31, 0xc7,(00), 0xb8, 0xc7,(00), 0x6f, 0x7f, 0x6e, 0x7e, Pf2,0xd6, Pf3,0x7e, Pe,0xd6, Pe,0x6e, Pe,0x7e },
+	{ AMOVQ,	ymovq,	Pw, 0x89, 0x8b, 0x31, 0xc7,(00), 0xb8, 0xc7,(00), 0x6f, 0x7f, 0x6e, 0x7e, Pf2,0xd6, Pf3,0x7e, Pe,0xd6, Pe,0x6e, Pe,0x7e,0 },
 	{ AMOVQOZX,	ymrxr,	Pf3, 0xd6,0x7e },
 	{ AMOVSB,	ynone,	Pb, 0xa4 },
 	{ AMOVSD,	yxmov,	Pf2, 0x10,0x11 },
@@ -935,7 +935,7 @@ Optab optab[] =
 	{ AMOVSW,	ynone,	Pe, 0xa5 },
 	{ AMOVUPD,	yxmov,	Pe, 0x10,0x11 },
 	{ AMOVUPS,	yxmov,	Pm, 0x10,0x11 },
-	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0xb8,0xc7,(00) },
+	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0xb8,0xc7,(00),0 },
 	{ AMOVWLSX,	yml_rl,	Pm, 0xbf },
 	{ AMOVWLZX,	yml_rl,	Pm, 0xb7 },
 	{ AMOVWQSX,	yml_rl,	Pw, 0x0f,0xbf },
diff --git a/src/cmd/8l/l.h b/src/cmd/8l/l.h
index 2167ccb003..814aa14582 100644
--- a/src/cmd/8l/l.h
+++ b/src/cmd/8l/l.h
@@ -175,7 +175,7 @@ struct	Optab
 	short	as;
 	uchar*	ytab;
 	uchar	prefix;
-	uchar	op[12];
+	uchar	op[13];
 };
 
 enum
diff --git a/src/cmd/8l/optab.c b/src/cmd/8l/optab.c
index 78fe45238e..a4c40e8e37 100644
--- a/src/cmd/8l/optab.c
+++ b/src/cmd/8l/optab.c
@@ -152,6 +152,17 @@ uchar	ymovb[] =
 	Yi32,	Ymb,	Zibo_m,	2,
 	0
 };
+uchar	ymovw[] =
+{
+	Yrl,	Yml,	Zr_m,	1,
+	Yml,	Yrl,	Zm_r,	1,
+	Yi0,	Yrl,	Zclr,	1+2,
+//	Yi0,	Yml,	Zibo_m,	2,	// shorter but slower AND $0,dst
+	Yi32,	Yrl,	Zil_rp,	1,
+	Yi32,	Yml,	Zilo_m,	2,
+	Yiauto,	Yrl,	Zaut_r,	1,
+	0
+};
 uchar	ymovl[] =
 {
 	Yrl,	Yml,	Zr_m,	1,
@@ -162,7 +173,7 @@ uchar	ymovl[] =
 	Yi32,	Yml,	Zilo_m,	2,
 	Yml,	Yxr,	Zm_r_xm,	2,	// XMM MOVD (32 bit)
 	Yxr,	Yml,	Zr_m_xm,	2,	// XMM MOVD (32 bit)
-	Yiauto,	Yrl,	Zaut_r,	2,
+	Yiauto,	Yrl,	Zaut_r,	1,
 	0
 };
 uchar	ymovq[] =
@@ -592,8 +603,8 @@ Optab optab[] =
 	{ ALSLL,	yml_rl,	Pm, 0x03  },
 	{ ALSLW,	yml_rl,	Pq, 0x03  },
 	{ AMOVB,	ymovb,	Pb, 0x88,0x8a,0xb0,0xc6,(00) },
-	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),Pe,0x6e,Pe,0x7e },
-	{ AMOVW,	ymovl,	Pe, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00) },
+	{ AMOVL,	ymovl,	Px, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),Pe,0x6e,Pe,0x7e,0 },
+	{ AMOVW,	ymovw,	Pe, 0x89,0x8b,0x31,0x83,(04),0xb8,0xc7,(00),0 },
 	{ AMOVQ,	ymovq,	Pf3, 0x7e },
 	{ AMOVBLSX,	ymb_rl,	Pm, 0xbe },
 	{ AMOVBLZX,	ymb_rl,	Pm, 0xb6 },
-- 
2.50.0