commit 9baddd3f21230c55f0ad2a10f5f20579dcf0a0bb [browse]
Author: Dmitri Shuralyov
Date: 2021-04-01 11:28:29 -04:00
[release-branch.go1.16] go1.16.3
Change-Id: Iace7cfec757a6d0bac25f729be5ecb2ae3b59d74
Reviewed-on: https://go-review.googlesource.com/c/go/+/306569
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
commit 96139f25993f3d8122e27a6fec877a4d4f69f83b [browse]
Author: Pat Gavlin
Date: 2021-03-26 14:46:37 Z
[release-branch.go1.16] cmd/compile: fix long RMW bit operations on AMD64
Under certain circumstances, the existing rules for bit operations can
produce code that writes beyond its intended bounds. For example,
consider the following code:
func repro(b []byte, addr, bit int32) {
_ = b[3]
v := uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 | 1<<(bit&31)
b[0] = byte(v)
b[1] = byte(v >> 8)
b[2] = byte(v >> 16)
b[3] = byte(v >> 24)
}
Roughly speaking:
1. The expression `1 << (bit & 31)` is rewritten into `(SHLL 1 bit)`
2. The expression `uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 |
uint32(b[3])<<24` is rewritten into `(MOVLload &b[0])`
3. The statements `b[0] = byte(v) ... b[3] = byte(v >> 24)` are
rewritten into `(MOVLstore &b[0], v)`
4. `(ORL (SHLL 1, bit) (MOVLload &b[0]))` is rewritten into
`(BTSL (MOVLload &b[0]) bit)`. This is a valid transformation because
the destination is a register: in this case, the bit offset is masked
by the number of bits in the destination register. This is identical
to the masking performed by `SHL`.
5. `(MOVLstore &b[0] (BTSL (MOVLload &b[0]) bit))` is rewritten into
`(BTSLmodify &b[0] bit)`. This is an invalid transformation because
the destination is memory: in this case, the bit offset is not
masked, and the chosen instruction may write outside its intended
32-bit location.
These changes fix the invalid rewrite performed in step (5) by
explicitly maksing the bit offset operand to `BT(S|R|C)(L|Q)modify`. In
the example above, the adjusted rules produce
`(BTSLmodify &b[0] (ANDLconst [31] bit))` in step (5).
These changes also add several new rules to rewrite bit sets, toggles,
and clears that are rooted at `(OR|XOR|AND)(L|Q)modify` operators into
appropriate `BT(S|R|C)(L|Q)modify` operators. These rules catch cases
where `MOV(L|Q)store ((OR|XOR|AND)(L|Q) ...)` is rewritten to
`(OR|XOR|AND)(L|Q)modify` before the `(OR|XOR|AND)(L|Q) ...` can be
rewritten to `BT(S|R|C)(L|Q) ...`.
Overall, compilecmp reports small improvements in code size on
darwin/amd64 when the changes to the compiler itself are exlcuded:
file before after Δ %
runtime.s 536464 536412 -52 -0.010%
bytes.s 32629 32593 -36 -0.110%
strings.s 44565 44529 -36 -0.081%
os/signal.s 7967 7959 -8 -0.100%
cmd/vendor/golang.org/x/sys/unix.s 81686 81678 -8 -0.010%
math/big.s 188235 188253 +18 +0.010%
cmd/link/internal/loader.s 89295 89056 -239 -0.268%
cmd/link/internal/ld.s 633551 633232 -319 -0.050%
cmd/link/internal/arm.s 18934 18928 -6 -0.032%
cmd/link/internal/arm64.s 31814 31801 -13 -0.041%
cmd/link/internal/riscv64.s 7347 7345 -2 -0.027%
cmd/compile/internal/ssa.s 4029173 4033066 +3893 +0.097%
total 21298280 21301472 +3192 +0.015%
Fixes #45253
Change-Id: I2e560548b515865129e1724e150e30540e9d29ce
GitHub-Last-Rev: ab94ede1d097f920a9d1d3da403c8e4a3d8f6d44
GitHub-Pull-Request: golang/go#45242
Reviewed-on: https://go-review.googlesource.com/c/go/+/305069
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
commit 887c0d890fd33a72cc1de6316252ba37649145cb [browse]
Author: Michael Pratt
Date: 2021-03-11 12:28:45 -05:00
[release-branch.go1.16] runtime: non-strict InlTreeIndex lookup in Frames.Next
When using cgo, some of the frames can be provided by cgoTraceback, a
cgo-provided function to generate C tracebacks. Unlike Go tracebacks,
cgoTraceback has no particular guarantees that it produces valid
tracebacks.
If one of the (invalid) frames happens to put the PC in the alignment
region at the end of a function (filled with int 3's on amd64), then
Frames.Next will find a valid funcInfo for the PC, but pcdatavalue will
panic because PCDATA doesn't cover this PC.
Tolerate this case by doing a non-strict PCDATA lookup. We'll still show
a bogus frame, but at least avoid throwing.
For #44971
Fixes #45303
Change-Id: I9eed728470d6f264179a7615bd19845c941db78c
Reviewed-on: https://go-review.googlesource.com/c/go/+/301369
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
(cherry picked from commit e4a4161f1f3157550846e1b6bd4fe83aae15778e)
Reviewed-on: https://go-review.googlesource.com/c/go/+/305889
commit 3a45c13094e2bf1ac1430ce6af8b8be80bf0938e [browse]
Author: Keith Randall
Date: 2021-03-23 14:48:47 -07:00
[release-branch.go1.16] cmd/compile: disable shortcircuit optimization for intertwined phi values
We need to be careful that when doing value graph surgery, we not
re-substitute a value that has already been substituted. That can lead
to confusing a previous iteration's value with the current iteration's
value.
The simple fix in this CL just aborts the optimization if it detects
intertwined phis (a phi which is the argument to another phi). It
might be possible to keep the optimization with a more complicated
CL, but:
1) This CL is clearly safe to backport.
2) There were no instances of this abort triggering in
all.bash, prior to the test introduced in this CL.
Fixes #45192
Change-Id: I2411dca03948653c053291f6829a76bec0c32330
Reviewed-on: https://go-review.googlesource.com/c/go/+/304251
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
(cherry picked from commit 771c57e68ed5ef2bbb0eafc0d48419f59d143932)
Reviewed-on: https://go-review.googlesource.com/c/go/+/304530
commit 2940614c63ed1351c47038db4ec613a37d1e72fd [browse]
Author: Bryan C. Mills
Date: 2021-03-09 17:23:04 -05:00
[release-branch.go1.16] cmd/go: allow '+' in package import paths in module mode
This change upgrades x/mod to pull in the fix from CL 300152.
Updates #44776.
Fixes #44885.
Change-Id: I273f41df2abfff76d91315b7f19fce851c8770d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/300176
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
(cherry picked from commit d33e2192a71c33a604af247161ba1d2c1969e4c7)
Reviewed-on: https://go-review.googlesource.com/c/go/+/300153
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