The timerpMask optimization updates a mask of Ps (potentially)
containing timers in pidleget / pidleput. For correctness, it depends on
the assumption that new timers can only be added to a P's own heap.

addtimer violates this assumption if it is preempted after computing pp.
That G may then run on a different P, but adding a timer to the original
P's heap.

Avoid this by disabling preemption while pp is in use.

Other uses of doaddtimer should be OK:

* moveTimers: always moves to the current P's heap
* modtimer, cleantimers, addAdjustedTimers, runtimer: does not add net
  new timers to the heap while locked

For #44868
Fixes #44869

Change-Id: I4a5d080865e854931d0a3a09a51ca36879101d72
Reviewed-on: https://go-review.googlesource.com/c/go/+/300610
Trust: Michael Pratt <[email protected]>
Run-TryBot: Michael Pratt <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
TryBot-Result: Go Bot <[email protected]>
(cherry picked from commit aa26687)
Reviewed-on: https://go-review.googlesource.com/c/go/+/300611

…o help install'

Fixes #44860

Change-Id: I5a12c6437a91ce59307483ffcc70e084edc32197
Reviewed-on: https://go-review.googlesource.com/c/go/+/301329
Trust: Jay Conrod <[email protected]>
Run-TryBot: Jay Conrod <[email protected]>
Reviewed-by: Bryan C. Mills <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
TryBot-Result: Go Bot <[email protected]>
(cherry picked from commit 86bbf4b)
Reviewed-on: https://go-review.googlesource.com/c/go/+/301429

…ing it

parent's helperNames has not been set when frameSkip called, moving
helperNames initilazing to frameSkip.

For #44887
Fixes #44888

Change-Id: I5107c5951033e5e47d1ac441eac3ba5344a7bdc0
GitHub-Last-Rev: 44b90b2
GitHub-Pull-Request: #45071
Reviewed-on: https://go-review.googlesource.com/c/go/+/302469
Trust: Cherry Zhang <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Go Bot <[email protected]>
(cherry picked from commit 6704843)
Reviewed-on: https://go-review.googlesource.com/c/go/+/303189
Trust: Ian Lance Taylor <[email protected]>
Reviewed-by: Emmanuel Odeke <[email protected]>

…from missing ziphash file

Previously, if an extracted module directory existed in the module
cache, but the corresponding ziphash file did not, if the sum was
missing from go.sum, we would not verify the sum. This caused 'go get'
not to write missing sums. 'go build' in readonly mode (now the
default) checks for missing sums and doesn't attempt to fetch modules
that can't be verified against go.sum.

With this change, when requesting the module directory with
modfetch.DownloadDir, if the ziphash file is missing, the go command
will re-hash the zip without downloading or re-extracting it again.

Note that the go command creates the ziphash file before the module
directory, but another program could remove it separately, and it
might not be present after a crash.

Fixes #44812

Change-Id: I64551e048a3ba17d069de1ec123d5b8b2757543c
Reviewed-on: https://go-review.googlesource.com/c/go/+/298352
Trust: Jay Conrod <[email protected]>
Run-TryBot: Jay Conrod <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Bryan C. Mills <[email protected]>
(cherry picked from commit 302a400)
Reviewed-on: https://go-review.googlesource.com/c/go/+/298851

…table static tmps

Static tmps are private to a package, but with plugins a package
can be shared among multiple DSOs. They need to have a consistent
view of the static tmps, especially for writable ones. So export
them. (Read-only static tmps have the same values anyway, so it
doesn't matter. Also Mach-O doesn't support dynamically exporting
read-only symbols anyway.)

Updates #44956.
Fixes #45030.

Change-Id: I921e25b7ab73cd5d5347800eccdb7931e3448779
Reviewed-on: https://go-review.googlesource.com/c/go/+/301793
Trust: Cherry Zhang <[email protected]>
Run-TryBot: Cherry Zhang <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
(cherry picked from commit de012bc095359e1b552d4ea6fb6b2995f3ab04f5)
Reviewed-on: https://go-review.googlesource.com/c/go/+/302449

…dent packages

Currently, in the trampoline generation pass we expect packages
are laid out in dependency order, so a cross-package jump always
has a known target address so we can check if a trampoline is
needed. With linknames, there can be cycles in the package
dependency graph, making this algorithm no longer work. For them,
as the target address is unkown we conservatively generate a
trampoline. This may generate unnecessary trampolines (if the
packages turn out laid together), but package cycles are extremely
rare so this is fine.

Updates #44639.
Fixes #44640.

Change-Id: I2dc2998edacbda27d726fc79452313a21d07787a
Reviewed-on: https://go-review.googlesource.com/c/go/+/292490
Trust: Cherry Zhang <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>
(cherry picked from commit 098504c)
Reviewed-on: https://go-review.googlesource.com/c/go/+/296909
Run-TryBot: Cherry Zhang <[email protected]>
TryBot-Result: Go Bot <[email protected]>

…un.bat, run.rc

We used to clear GOPATH in all the build scripts.
Clearing GOPATH is misleading at best, since you just end up
with the default GOPATH (%USERPROFILE%\go on Windows).
Unless that's your GOROOT, in which case you end up with a
fatal error from the go command (#43938).

run.bash changed to setting GOPATH=/dev/null, which has no
clear analogue on Windows.

run.rc still clears GOPATH.

Change them all to set GOPATH to a non-existent directory
/nonexist-gopath or c:\nonexist-gopath.

For #45238.
Fixes #45240.

Change-Id: I51edd66d37ff6a891b0d0541d91ecba97fbbb03d
Reviewed-on: https://go-review.googlesource.com/c/go/+/288818
Trust: Russ Cox <[email protected]>
Trust: Jason A. Donenfeld <[email protected]>
Reviewed-by: Cherry Zhang <[email protected]>
Reviewed-by: Alex Brainman <[email protected]>
Reviewed-by: Jason A. Donenfeld <[email protected]>
(cherry picked from commit bb6efb9)
Reviewed-on: https://go-review.googlesource.com/c/go/+/304772
Run-TryBot: Dmitri Shuralyov <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Alexander Rakoczy <[email protected]>
Reviewed-by: Carlos Amedee <[email protected]>
Trust: Carlos Amedee <[email protected]>

…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 <[email protected]>
Run-TryBot: Bryan C. Mills <[email protected]>
Reviewed-by: Jay Conrod <[email protected]>
TryBot-Result: Go Bot <[email protected]>
(cherry picked from commit d33e219)
Reviewed-on: https://go-review.googlesource.com/c/go/+/300153

…n 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 <[email protected]>
Trust: Josh Bleecher Snyder <[email protected]>
Run-TryBot: Keith Randall <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Josh Bleecher Snyder <[email protected]>
(cherry picked from commit 771c57e)
Reviewed-on: https://go-review.googlesource.com/c/go/+/304530

…ames.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 <[email protected]>
Run-TryBot: Michael Pratt <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Cherry Zhang <[email protected]>
(cherry picked from commit e4a4161)
Reviewed-on: https://go-review.googlesource.com/c/go/+/305889

…MD64

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: ab94ede
GitHub-Pull-Request: #45242
Reviewed-on: https://go-review.googlesource.com/c/go/+/305069
Trust: Emmanuel Odeke <[email protected]>
Run-TryBot: Emmanuel Odeke <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Keith Randall <[email protected]>

Change-Id: Iace7cfec757a6d0bac25f729be5ecb2ae3b59d74
Reviewed-on: https://go-review.googlesource.com/c/go/+/306569
Run-TryBot: Dmitri Shuralyov <[email protected]>
Run-TryBot: Carlos Amedee <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: David Chase <[email protected]>
TryBot-Result: Go Bot <[email protected]>