2018-09-14 11:57:57 -06:00
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// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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var x [2]bool
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var x8 [2]uint8
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var x16 [2]uint16
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var x32 [2]uint32
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var x64 [2]uint64
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func compMem1() int {
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// amd64:`CMPB\t"".x\+1\(SB\), [$]0`
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if x[1] {
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return 1
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}
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// amd64:`CMPB\t"".x8\+1\(SB\), [$]7`
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if x8[1] == 7 {
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return 1
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}
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// amd64:`CMPW\t"".x16\+2\(SB\), [$]7`
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if x16[1] == 7 {
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return 1
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}
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// amd64:`CMPL\t"".x32\+4\(SB\), [$]7`
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if x32[1] == 7 {
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return 1
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}
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// amd64:`CMPQ\t"".x64\+8\(SB\), [$]7`
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if x64[1] == 7 {
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return 1
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}
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return 0
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}
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//go:noinline
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func f(x int) bool {
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return false
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}
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//go:noinline
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func f8(x int) int8 {
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return 0
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}
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//go:noinline
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func f16(x int) int16 {
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return 0
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}
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//go:noinline
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func f32(x int) int32 {
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return 0
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}
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//go:noinline
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func f64(x int) int64 {
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return 0
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}
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func compMem2() int {
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// amd64:`CMPB\t8\(SP\), [$]0`
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if f(3) {
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return 1
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}
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// amd64:`CMPB\t8\(SP\), [$]7`
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if f8(3) == 7 {
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return 1
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}
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// amd64:`CMPW\t8\(SP\), [$]7`
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if f16(3) == 7 {
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return 1
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}
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// amd64:`CMPL\t8\(SP\), [$]7`
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if f32(3) == 7 {
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return 1
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}
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// amd64:`CMPQ\t8\(SP\), [$]7`
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if f64(3) == 7 {
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return 1
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}
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return 0
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}
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2018-10-26 11:52:59 -06:00
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func compMem3(x, y *int) (int, bool) {
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// We can do comparisons of a register with memory even if
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// the register is used subsequently.
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r := *x
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// amd64:`CMPQ\t\(`
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// 386:`CMPL\t\(`
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return r, r < *y
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}
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2020-01-30 11:17:01 -07:00
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// The following functions test that indexed load/store operations get generated.
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func idxInt8(x, y []int8, i int) {
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var t int8
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// amd64: `MOVBL[SZ]X\t1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\), [A-Z]+[0-9]*`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVBL[SZ]X\t1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\), [A-Z]+[0-9]*`
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2020-01-30 11:17:01 -07:00
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t = x[i+1]
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// amd64: `MOVB\t[A-Z]+[0-9]*, 1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\)`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVB\t[A-Z]+[0-9]*, 1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\)`
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2020-01-30 11:17:01 -07:00
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y[i+1] = t
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// amd64: `MOVB\t[$]77, 1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\)`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVB\t[$]77, 1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\)`
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2020-01-30 11:17:01 -07:00
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x[i+1] = 77
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}
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func idxInt16(x, y []int16, i int) {
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var t int16
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// amd64: `MOVWL[SZ]X\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\), [A-Z]+[0-9]*`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVWL[SZ]X\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\), [A-Z]+[0-9]*`
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2020-01-30 11:17:01 -07:00
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t = x[i+1]
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// amd64: `MOVW\t[A-Z]+[0-9]*, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\)`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVW\t[A-Z]+[0-9]*, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\)`
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2020-01-30 11:17:01 -07:00
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y[i+1] = t
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// amd64: `MOVWL[SZ]X\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\), [A-Z]+[0-9]*`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVWL[SZ]X\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\), [A-Z]+[0-9]*`
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2020-01-30 11:17:01 -07:00
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t = x[16*i+1]
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// amd64: `MOVW\t[A-Z]+[0-9]*, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
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// 386: `MOVW\t[A-Z]+[0-9]*, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\)`
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2020-01-30 11:17:01 -07:00
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y[16*i+1] = t
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// amd64: `MOVW\t[$]77, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\)`
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cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVW\t[$]77, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
x[i+1] = 77
|
|
|
|
// amd64: `MOVW\t[$]77, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVW\t[$]77, 2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
x[16*i+1] = 77
|
|
|
|
}
|
|
|
|
|
|
|
|
func idxInt32(x, y []int32, i int) {
|
|
|
|
var t int32
|
|
|
|
// amd64: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[i+1]
|
|
|
|
// amd64: `MOVL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[i+1] = t
|
|
|
|
// amd64: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
t = x[2*i+1]
|
|
|
|
// amd64: `MOVL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
y[2*i+1] = t
|
|
|
|
// amd64: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), [A-Z]+[0-9]*`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[16*i+1]
|
|
|
|
// amd64: `MOVL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[16*i+1] = t
|
|
|
|
// amd64: `MOVL\t[$]77, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t[$]77, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
x[i+1] = 77
|
|
|
|
// amd64: `MOVL\t[$]77, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `MOVL\t[$]77, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
x[16*i+1] = 77
|
|
|
|
}
|
|
|
|
|
|
|
|
func idxInt64(x, y []int64, i int) {
|
|
|
|
var t int64
|
|
|
|
// amd64: `MOVQ\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
t = x[i+1]
|
|
|
|
// amd64: `MOVQ\t[A-Z]+[0-9]*, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
y[i+1] = t
|
|
|
|
// amd64: `MOVQ\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\), [A-Z]+[0-9]*`
|
|
|
|
t = x[16*i+1]
|
|
|
|
// amd64: `MOVQ\t[A-Z]+[0-9]*, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\)`
|
|
|
|
y[16*i+1] = t
|
|
|
|
// amd64: `MOVQ\t[$]77, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+1] = 77
|
|
|
|
// amd64: `MOVQ\t[$]77, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\)`
|
|
|
|
x[16*i+1] = 77
|
|
|
|
}
|
|
|
|
|
|
|
|
func idxFloat32(x, y []float32, i int) {
|
|
|
|
var t float32
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSS\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
|
|
|
// 386/sse2: `MOVSS\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[i+1]
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSS\tX[0-9]+, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
|
|
|
// 386/sse2: `MOVSS\tX[0-9]+, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[i+1] = t
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSS\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), X[0-9]+`
|
|
|
|
// 386/sse2: `MOVSS\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), X[0-9]+`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[16*i+1]
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSS\tX[0-9]+, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
|
|
|
// 386/sse2: `MOVSS\tX[0-9]+, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[16*i+1] = t
|
|
|
|
}
|
|
|
|
|
|
|
|
func idxFloat64(x, y []float64, i int) {
|
|
|
|
var t float64
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSD\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
|
|
|
// 386/sse2: `MOVSD\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[i+1]
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSD\tX[0-9]+, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
// 386/sse2: `MOVSD\tX[0-9]+, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[i+1] = t
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSD\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\), X[0-9]+`
|
|
|
|
// 386/sse2: `MOVSD\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\), X[0-9]+`
|
2020-01-30 11:17:01 -07:00
|
|
|
t = x[16*i+1]
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// amd64: `MOVSD\tX[0-9]+, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\)`
|
|
|
|
// 386/sse2: `MOVSD\tX[0-9]+, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\)`
|
2020-01-30 11:17:01 -07:00
|
|
|
y[16*i+1] = t
|
|
|
|
}
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
|
2020-04-11 23:15:58 -06:00
|
|
|
func idxLoadPlusOp32(x []int32, i int) int32 {
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s := x[0]
|
|
|
|
// 386: `ADDL\t4\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
2020-04-11 23:15:58 -06:00
|
|
|
// amd64: `ADDL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s += x[i+1]
|
|
|
|
// 386: `SUBL\t8\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
2020-04-11 23:15:58 -06:00
|
|
|
// amd64: `SUBL\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s -= x[i+2]
|
|
|
|
// 386: `IMULL\t12\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
|
|
|
s *= x[i+3]
|
|
|
|
// 386: `ANDL\t16\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
2020-04-11 23:15:58 -06:00
|
|
|
// amd64: `ANDL\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s &= x[i+4]
|
|
|
|
// 386: `ORL\t20\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
2020-04-11 23:15:58 -06:00
|
|
|
// amd64: `ORL\t20\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s |= x[i+5]
|
|
|
|
// 386: `XORL\t24\([A-Z]+\)\([A-Z]+\*4\), [A-Z]+`
|
2020-04-11 23:15:58 -06:00
|
|
|
// amd64: `XORL\t24\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
s ^= x[i+6]
|
|
|
|
return s
|
|
|
|
}
|
|
|
|
|
2020-04-11 23:15:58 -06:00
|
|
|
func idxLoadPlusOp64(x []int64, i int) int64 {
|
|
|
|
s := x[0]
|
|
|
|
// amd64: `ADDQ\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
s += x[i+1]
|
|
|
|
// amd64: `SUBQ\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
s -= x[i+2]
|
|
|
|
// amd64: `ANDQ\t24\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
s &= x[i+3]
|
|
|
|
// amd64: `ORQ\t32\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
s |= x[i+4]
|
|
|
|
// amd64: `XORQ\t40\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
|
|
|
s ^= x[i+5]
|
|
|
|
return s
|
|
|
|
}
|
|
|
|
|
2020-04-13 10:59:20 -06:00
|
|
|
func idxStorePlusOp32(x []int32, i int, v int32) {
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
// 386: `ADDL\t[A-Z]+, 4\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ADDL\t[A-Z]+[0-9]*, 4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+1] += v
|
|
|
|
// 386: `SUBL\t[A-Z]+, 8\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `SUBL\t[A-Z]+[0-9]*, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+2] -= v
|
|
|
|
// 386: `ANDL\t[A-Z]+, 12\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ANDL\t[A-Z]+[0-9]*, 12\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+3] &= v
|
|
|
|
// 386: `ORL\t[A-Z]+, 16\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ORL\t[A-Z]+[0-9]*, 16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+4] |= v
|
|
|
|
// 386: `XORL\t[A-Z]+, 20\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `XORL\t[A-Z]+[0-9]*, 20\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+5] ^= v
|
|
|
|
|
|
|
|
// 386: `ADDL\t[$]77, 24\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ADDL\t[$]77, 24\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+6] += 77
|
|
|
|
// 386: `ANDL\t[$]77, 28\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ANDL\t[$]77, 28\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+7] &= 77
|
|
|
|
// 386: `ORL\t[$]77, 32\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `ORL\t[$]77, 32\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+8] |= 77
|
|
|
|
// 386: `XORL\t[$]77, 36\([A-Z]+\)\([A-Z]+\*4\)`
|
2020-04-13 10:59:20 -06:00
|
|
|
// amd64: `XORL\t[$]77, 36\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\)`
|
|
|
|
x[i+9] ^= 77
|
|
|
|
}
|
|
|
|
|
|
|
|
func idxStorePlusOp64(x []int64, i int, v int64) {
|
|
|
|
// amd64: `ADDQ\t[A-Z]+[0-9]*, 8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+1] += v
|
|
|
|
// amd64: `SUBQ\t[A-Z]+[0-9]*, 16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+2] -= v
|
|
|
|
// amd64: `ANDQ\t[A-Z]+[0-9]*, 24\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+3] &= v
|
|
|
|
// amd64: `ORQ\t[A-Z]+[0-9]*, 32\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+4] |= v
|
|
|
|
// amd64: `XORQ\t[A-Z]+[0-9]*, 40\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+5] ^= v
|
|
|
|
|
|
|
|
// amd64: `ADDQ\t[$]77, 48\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+6] += 77
|
|
|
|
// amd64: `ANDQ\t[$]77, 56\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+7] &= 77
|
|
|
|
// amd64: `ORQ\t[$]77, 64\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
|
|
|
x[i+8] |= 77
|
|
|
|
// amd64: `XORQ\t[$]77, 72\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\)`
|
cmd/compile: convert 386 port to use addressing modes pass (take 2)
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-03-24 14:39:44 -06:00
|
|
|
x[i+9] ^= 77
|
|
|
|
}
|
2020-03-19 18:48:42 -06:00
|
|
|
|
|
|
|
func idxCompare(i int) int {
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVBLZX\t1\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x8[i+1] < x8[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVWLZX\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x16[i+1] < x16[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVWLZX\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x16[16*i+1] < x16[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x32[i+1] < x32[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVL\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x32[16*i+1] < x32[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVQ\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x64[i+1] < x64[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVQ\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x64[16*i+1] < x64[0] {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVBLZX\t2\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*1\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x8[i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVWLZX\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*2\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x16[i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVWLZX\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[12]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x16[16*i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVL\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x32[i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVL\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[14]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x32[16*i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVQ\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x64[i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
2020-04-13 10:49:59 -06:00
|
|
|
// amd64: `MOVQ\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*[18]\), [A-Z]+[0-9]*`
|
2020-03-19 18:48:42 -06:00
|
|
|
if x64[16*i+2] < 77 {
|
|
|
|
return 0
|
|
|
|
}
|
|
|
|
return 1
|
|
|
|
}
|
2020-07-27 10:45:21 -06:00
|
|
|
|
|
|
|
func idxFloatOps(a []float64, b []float32, i int) (float64, float32) {
|
|
|
|
c := float64(7)
|
|
|
|
// amd64: `ADDSD\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
|
|
|
c += a[i+1]
|
|
|
|
// amd64: `SUBSD\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
|
|
|
c -= a[i+2]
|
|
|
|
// amd64: `MULSD\t24\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
|
|
|
c *= a[i+3]
|
|
|
|
// amd64: `DIVSD\t32\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*8\), X[0-9]+`
|
|
|
|
c /= a[i+4]
|
|
|
|
|
|
|
|
d := float32(8)
|
|
|
|
// amd64: `ADDSS\t4\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
|
|
|
d += b[i+1]
|
|
|
|
// amd64: `SUBSS\t8\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
|
|
|
d -= b[i+2]
|
|
|
|
// amd64: `MULSS\t12\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
|
|
|
d *= b[i+3]
|
|
|
|
// amd64: `DIVSS\t16\([A-Z]+[0-9]*\)\([A-Z]+[0-9]*\*4\), X[0-9]+`
|
|
|
|
d /= b[i+4]
|
|
|
|
return c, d
|
|
|
|
}
|