This reverts commit http://go.dev/cl//484859
Reason for revert: causes linker errors in a number of google-internal tests.
Change-Id: I322252f784a46d2b1d447ebcdca86ce14bc0cc91
Reviewed-on: https://go-review.googlesource.com/c/go/+/485755
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[This is a roll-forward of CL 479095, which was reverted due to a bad
interaction between inlining and escape analysis, then later fixed
fist with an attempt in CL 482355, then again in 484859 .]
Currently, when the inliner is determining if a function is
inlineable, it descends into the bodies of closures constructed by
that function. This has several unfortunate consequences:
- If the closure contains a disallowed operation (e.g., a defer), then
the outer function can't be inlined. It makes sense that the
*closure* can't be inlined in this case, but it doesn't make sense
to punish the function that constructs the closure.
- The hairiness of the closure counts against the inlining budget of
the outer function. Since we currently copy the closure body when
inlining the outer function, this makes sense from the perspective
of export data size and binary size, but ultimately doesn't make
much sense from the perspective of what should be inlineable.
- Since the inliner walks into every closure created by an outer
function in addition to starting a walk at every closure, this adds
an n^2 factor to inlinability analysis.
This CL simply drops this behavior.
In std, this makes 57 more functions inlinable, and disallows inlining
for 10 (due to the basic instability of our bottom-up inlining
approach), for an net increase of 47 inlinable functions (+0.6%).
This will help significantly with the performance of the functions to
be added for #56102, which have a somewhat complicated nesting of
closures with a performance-critical fast path.
The downside of this seems to be a potential increase in export data
and text size, but the practical impact of this seems to be
negligible:
│ before │ after │
│ bytes │ bytes vs base │
Go/binary 15.12Mi ± 0% 15.14Mi ± 0% +0.16% (n=1)
Go/text 5.220Mi ± 0% 5.237Mi ± 0% +0.32% (n=1)
Compile/binary 22.92Mi ± 0% 22.94Mi ± 0% +0.07% (n=1)
Compile/text 8.428Mi ± 0% 8.435Mi ± 0% +0.08% (n=1)
Updates #56102.
Change-Id: I6e938d596992ffb473cf51e7e598f372ce08deb0
Reviewed-on: https://go-review.googlesource.com/c/go/+/484860
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This patch generalizes the code in the inliner that marks unreferenced
hidden closure functions as dead. Rather than doing the marking on the
fly (previous approach), this new approach does a single pass at the
end of inlining, which catches more dead functions.
Fixes#59638.
Updates #59404.
Updates #59547.
Change-Id: I54fd63e9e37c9123b08a3e7def7d1989919bba91
Reviewed-on: https://go-review.googlesource.com/c/go/+/484859
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CL 399694 added constant-fold switch early in compilation. So function:
func f() string {
switch intSize {
case 32:
return "32"
case 64:
return "64"
default:
panic("unreachable")
}
}
will be constant-fold to:
func f() string {
switch intSize {
case 64:
return "64"
}
}
When this function get inlined, there is a check whether we can delay
declaring the result parameter until the "return" statement. For the
original function, we can't delay the result, because there's more than
one return statement. However, the constant-fold one can, because
there's on one return statement in the body now. The result parameter
~R0 ends up declaring inside the switch statement scope.
Now, when walking the switch statement, it's re-written into if-else
statement. Without typecheck.EvalConst, the if condition "if 64 == 64"
is passed as-is to the ssa generation pass. Because "64 == 64" is not a
constant, the ssagen creates normal blocks for branching the results.
This confuses the liveness analysis, because ~R0 is only live inside the
if block. With typecheck.EvalConst, "64 == 64" is evaluated to "true",
so ssagen can branch the result without emitting conditional blocks.
Instead, the constant-fold can be re-written as:
switch {
case true:
// Body
}
So it does not depend on the delay results check during inlining. Adding
a test, which will fail when typecheck.EvalConst is removed, so we can
do the cleanup without breaking things.
Change-Id: I638730bb147140de84260653741431b807ff2f15
Reviewed-on: https://go-review.googlesource.com/c/go/+/484316
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Static init inliner is using typecheck.EvalConst to handle string
concatenation expressions. But static init inliner may reveal constant
expressions after substitution, and the compiler needs to evaluate those
expressions in non-constant semantic. Using typecheck.EvalConst, which
always evaluates expressions in constant semantic, is not the right
choice.
For safety, this CL fold the logic to handle string concatenation to
static init inliner, so there won't be regression in handling constant
expressions in non-constant semantic. And also, future CL can simplify
typecheck.EvalConst logic.
Updates #58293
Updates #58339Fixes#58439
Change-Id: I74068d99c245938e576afe9460cbd2b39677bbff
Reviewed-on: https://go-review.googlesource.com/c/go/+/466277
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(This is a retry of CL 462035 which was reverted at 474976.
The only change from that CL is the aix fix SRODATA->SNOPTRDATA
at inittask.go:141)
As described here:
https://github.com/golang/go/issues/31636#issuecomment-493271830
"Find the lexically earliest package that is not initialized yet,
but has had all its dependencies initialized, initialize that package,
and repeat."
Simplify the runtime a bit, by just computing the ordering required
in the linker and giving a list to the runtime.
Update #31636Fixes#57411
RELNOTE=yes
Change-Id: I28c09451d6aa677d7394c179d23c2c02c503fc56
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This reverts commit http://go.dev/cl/c/482356.
Reason for revert: Reverting this change again, since it is causing additional failures in google-internal testing.
Change-Id: I9234946f62e5bb18c2f873a65e8b298d04af0809
Reviewed-on: https://go-review.googlesource.com/c/go/+/484735
Reviewed-by: Florian Zenker <floriank@google.com>
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Range statement will mutate the key and value, so we should treat them as reassigned.
Fixes#59572
Change-Id: I9c6b67d938760a0c6a1d9739f2737c67af4a3a10
Reviewed-on: https://go-review.googlesource.com/c/go/+/483855
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Fixes#58141
Co-authored-by: Richard Musiol <neelance@gmail.com>
Co-authored-by: Achille Roussel <achille.roussel@gmail.com>
Co-authored-by: Julien Fabre <ju.pryz@gmail.com>
Co-authored-by: Evan Phoenix <evan@phx.io>
Change-Id: I49b66946acc90fdf09ed9223096bfec9a1e5b923
Reviewed-on: https://go-review.googlesource.com/c/go/+/479627
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For now, only apply the rule if either of arguments are constants. That
would catch a lot of real user code, without slowing down the compiler
with code generated for string comparison (experience in CL 410336).
Updates #57959Fixes#45928
Change-Id: Ie2e830d6d0d71cda3947818b22c2775bd94f7971
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So iterators that are in progress can know entries have been deleted and
terminate the iterator properly.
Update #55002
Update #56351Fixes#59411
Change-Id: I924f16a00fe4ed6564f730a677348a6011d3fb67
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Use the type of the store for the byteswap, not the type of the
store's value argument.
Normally when we're storing a 16-bit value, the value being stored is
also typed as 16 bits. But sometimes it is typed as something smaller,
usually because it is the result of an upcast from a smaller value,
and that upcast needs no instructions.
If the type of the store's arg is thinner than the type being stored,
and the byteswap'd value uses that thinner type, and the byteswap'd
value needs to be spilled & restored, that spill/restore happens using
the thinner type, which causes us to lose some of the top bits of the
value.
Fixes#59367
Change-Id: If6ce1e8a76f18bf8e9d79871b6caa438bc3cce4d
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[This is a roll-forward of CL 479095, which was reverted due to a bad
interaction between inlining and escape analysis since fixed in CL 482355.]
Currently, when the inliner is determining if a function is
inlineable, it descends into the bodies of closures constructed by
that function. This has several unfortunate consequences:
- If the closure contains a disallowed operation (e.g., a defer), then
the outer function can't be inlined. It makes sense that the
*closure* can't be inlined in this case, but it doesn't make sense
to punish the function that constructs the closure.
- The hairiness of the closure counts against the inlining budget of
the outer function. Since we currently copy the closure body when
inlining the outer function, this makes sense from the perspective
of export data size and binary size, but ultimately doesn't make
much sense from the perspective of what should be inlineable.
- Since the inliner walks into every closure created by an outer
function in addition to starting a walk at every closure, this adds
an n^2 factor to inlinability analysis.
This CL simply drops this behavior.
In std, this makes 57 more functions inlinable, and disallows inlining
for 10 (due to the basic instability of our bottom-up inlining
approach), for an net increase of 47 inlinable functions (+0.6%).
This will help significantly with the performance of the functions to
be added for #56102, which have a somewhat complicated nesting of
closures with a performance-critical fast path.
The downside of this seems to be a potential increase in export data
and text size, but the practical impact of this seems to be
negligible:
│ before │ after │
│ bytes │ bytes vs base │
Go/binary 15.12Mi ± 0% 15.14Mi ± 0% +0.16% (n=1)
Go/text 5.220Mi ± 0% 5.237Mi ± 0% +0.32% (n=1)
Compile/binary 22.92Mi ± 0% 22.94Mi ± 0% +0.07% (n=1)
Compile/text 8.428Mi ± 0% 8.435Mi ± 0% +0.08% (n=1)
Updates #56102.
Change-Id: I1f4fc96c71609c8feb59fecdb92b69ba7e3b5b41
Reviewed-on: https://go-review.googlesource.com/c/go/+/482356
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When a closure is inlined, it may contain other hidden closures, which
the inliner will duplicate, rendering the original nested closures as
unreachable. Because they are unreachable, they don't get processed in
escape analysis, meaning that go/defer statements don't get rewritten,
which can then in turn trigger errors in walk. This patch looks for
nested hidden closures and marks them as dead, so that they can be
skipped later on in the compilation flow. NB: if during escape
analysis we rediscover a hidden closure (due to an explicit reference)
that was previously marked dead, revive it at that point.
Fixes#59404.
Change-Id: I76db1e9cf1ee38bd1147aeae823f916dbbbf081b
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Currently, the prove pass can get knowledge from some specific logic
operators only before the CFG is explored, which means that the bounds
information of the branch will be ignored.
This CL updates the facts table by the logic operators in every
branch. Combined with the branch information, this will be helpful for
BCE in some circumstances.
Fixes#57243
Change-Id: I0bd164f1b47804ccfc37879abe9788740b016fd5
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Unified IR already records the correct type for them.
Fixes#59378
Change-Id: I275c45b48f67bde55c8e2079d60b5868d0acde7f
Reviewed-on: https://go-review.googlesource.com/c/go/+/481555
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Casting to a *uintptr is not ok if there isn't at least 8 bytes of
data backing that pointer (on 64-bit archs).
So although we end up making a slice of 0 length with that pointer,
the cast itself doesn't know that.
Instead, bail early if the result is going to be 0 length.
Fixes#59334
Change-Id: Id3c0e09d341d838835c0382cccfb0f71dc3dc7e6
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Currently, when the inliner is determining if a function is
inlineable, it descends into the bodies of closures constructed by
that function. This has several unfortunate consequences:
- If the closure contains a disallowed operation (e.g., a defer), then
the outer function can't be inlined. It makes sense that the
*closure* can't be inlined in this case, but it doesn't make sense
to punish the function that constructs the closure.
- The hairiness of the closure counts against the inlining budget of
the outer function. Since we currently copy the closure body when
inlining the outer function, this makes sense from the perspective
of export data size and binary size, but ultimately doesn't make
much sense from the perspective of what should be inlineable.
- Since the inliner walks into every closure created by an outer
function in addition to starting a walk at every closure, this adds
an n^2 factor to inlinability analysis.
This CL simply drops this behavior.
In std, this makes 57 more functions inlinable, and disallows inlining
for 10 (due to the basic instability of our bottom-up inlining
approach), for an net increase of 47 inlinable functions (+0.6%).
This will help significantly with the performance of the functions to
be added for #56102, which have a somewhat complicated nesting of
closures with a performance-critical fast path.
The downside of this seems to be a potential increase in export data
and text size, but the practical impact of this seems to be
negligible:
│ before │ after │
│ bytes │ bytes vs base │
Go/binary 15.12Mi ± 0% 15.14Mi ± 0% +0.16% (n=1)
Go/text 5.220Mi ± 0% 5.237Mi ± 0% +0.32% (n=1)
Compile/binary 22.92Mi ± 0% 22.94Mi ± 0% +0.07% (n=1)
Compile/text 8.428Mi ± 0% 8.435Mi ± 0% +0.08% (n=1)
Change-Id: Ie9e38104fed5689a94c368288653fd7cb4b7a35e
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The cast is proceeded by a bounds check. If the bounds check passes
then we know the pointer in the slice is non-nil.
... except casts to pointers of 0-sized arrays. They are strange, as
the bounds check can pass for a nil input.
Change-Id: Ic01cf4a82d59fbe3071d4b271c94efca9cafaec1
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Change the Checker.use/useLHS functions to report if all "used"
expressions evaluated without error. Use that information to
control whether to report an assignment mismatch error or not.
This will reduce the number of errors reported per assignment,
where the assignment mismatch is only one of the errors.
Change-Id: Ia0fc3203253b002e4e1d5759d8d5644999af6884
Reviewed-on: https://go-review.googlesource.com/c/go/+/478756
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For #55242
Change-Id: I092b1881623ea997b178d038c0afd10cd5bca937
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unsafe.SliceData can return pointers which are nil. That function gets
lowered to the SSA OpSlicePtr, which the compiler assumes is non-nil.
This used to be the case as OpSlicePtr was only used in situations
where the bounds check already passed. But with unsafe.SliceData that
is no longer the case.
There are situations where we know it is nil. Use Bounded() to
indicate that.
I looked through all the uses of OSPTR and added SetBounded where it
made sense. Most OSPTR results are passed directly to runtime calls
(e.g. memmove), so even if we know they are non-nil that info isn't
helpful.
Fixes#59293
Change-Id: I437a15330db48e0082acfb1f89caf8c56723fc51
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As with changes in prior CLs, we don't suppress legitimate
"declared but not used" errors anymore simply because the
respective variables are used in incorrect assignments,
unrelated to the variables in question.
Adjust several (ancient) tests accordingly.
Change-Id: I5826393264d9d8085c64777a330d4efeb735dd2d
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This CL re-introduces useLHS because we don't want to suppress
correct "declared but not used" errors for variables that only
appear on the LHS of an assignment (using Checker.use would mark
them as used).
This CL also adjusts a couple of places where types2 differed
from go/types (and suppressed valid "declared and not used"
errors). Now those errors are surfaced. Adjusted a handful of
tests accordingly.
Change-Id: Ia555139a05049887aeeec9e5221b1f41432c1a57
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Don't say "array length must be integer" if it is in fact an integer.
Fixes#59209
Change-Id: If60b93a0418f5837ac334412d3838eec25eeb855
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In the Sizes API, recognize an overflow (to a negative value) as a
consequence of an oversize value, and specify as such in the API.
Adjust the various size computations to take overflow into account.
Recognize a negative size or offset as an error and report it rather
than panicking.
Use the same protocol for results provided by the default (StdSizes)
and external Sizes implementations.
Add a new error code TypeTooLarge for the new errors.
Fixes#59190.
Fixes#59207.
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Under the right conditions we can optimize cmp comparisons to cmn
comparisons, such as:
func foo(a, b int) int {
var c int
if a + b < 0 {
c = 1
}
return c
}
Previously it's compiled as:
ADD R1, R0, R1
CMP $0, R1
CSET LT, R0
With this CL it's compiled as:
CMN R1, R0
CSET MI, R0
Here we need to pay attention to the overflow situation of a+b, the MI
flag means N==1, which doesn't honor the overflow flag V, its value
depends only on the sign of the result. So it has the same semantic of
the Go code, so it's correct.
Similarly, this CL also optimizes the case of >= comparison
using the PL conditional flag.
Change-Id: I47179faba5b30cca84ea69bafa2ad5241bf6dfba
Reviewed-on: https://go-review.googlesource.com/c/go/+/476116
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For #59169
Change-Id: Id72ad9fe8b6e1d7cf64f972520ae8858f70c025a
Reviewed-on: https://go-review.googlesource.com/c/go/+/478217
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Auto-Submit: Ian Lance Taylor <iant@golang.org>
Add the following common local transformations
(t + x) - (t + y) == x - y
(t + x) - (y + t) == x - y
(x + t) - (y + t) == x - y
(x + t) - (t + y) == x - y
(x - t) + (t + y) == x + y
(x - t) + (y + t) == x + y
The compiler itself matches such patterns many times. This also aligns with other popular compilers.
Fixes#59111
Change-Id: Ibdfdb414782f8fcaa20b84ac5d43d0d9ae2c7b60
GitHub-Last-Rev: 1aad82e62e
GitHub-Pull-Request: golang/go#59119
Reviewed-on: https://go-review.googlesource.com/c/go/+/477555
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
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This CL add support for instrinsifying the TrialingZeros{8,32,64}
functions for 386 architecture. We need handle the case when the input
is 0, which could lead to undefined output from the BSFL instruction.
Next CL will remove the assembly code in runtime/internal/sys package.
Change-Id: Ic168edf68e81bf69a536102100fdd3f56f0f4a1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/475735
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
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Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
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This patch changes the relative order of "CanInline" and "InlineCalls"
operations within the inliner for clumps of functions corresponding to
strongly connected components in the call graph. This helps increase
the amount of inlining within SCCs, particularly in Go's runtime
package, which has a couple of very large SCCs.
For a given SCC of the form { fn1, fn2, ... fnk }, the inliner would
(prior to this point) walk through the list of functions and for each
function first compute inlinability ("CanInline") and then perform
inlining ("InlineCalls"). This meant that if there was an inlinable
call from fn3 to fn4 (for example), this call would never be inlined,
since at the point fn3 was visited, we would not have computed
inlinability for fn4.
We now do inlinability analysis for all functions in an SCC first,
then do actual inlining for everything. This results in 47 additional
inlines in the Go runtime package (a fairly modest increase
percentage-wise of 0.6%).
Updates #58905.
Change-Id: I48dbb1ca16f0b12f256d9eeba8cf7f3e6dd853cd
Reviewed-on: https://go-review.googlesource.com/c/go/+/474955
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This reverts commit ce2a609909.
aka CL 462035
Reason for revert: this CL is causing some problems in some internal Google programs.
Change-Id: I4476b8d8d2c3d7b5703d1d85c93baebb4b4e5d26
Reviewed-on: https://go-review.googlesource.com/c/go/+/474976
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This issue has been fixed with unified IR, so just add a test.
Update #53087
Change-Id: I965d9f27529fa6b7c89e2921c65e5a100daeb9fe
Reviewed-on: https://go-review.googlesource.com/c/go/+/410197
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
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On ARM64, in -dynlink mode (building a shared library or a plugin),
accessing global variable is made using the GOT. Currently, the
GOT accessing instruction sequence our assembler generates doesn't
handle large offset well, so we don't fold the offset into loads
and stores in the compiler. Currently, the rewrite rules are
guarded with the -shared flag. However, the GOT access
instructions are only generated in the -dynlink mode (which
implies -shared, but not the other direction).
CL 445535 attempted to remove the guard althgether. But that
causes build failure for -dynlink mode for the reason above. This
CL changes it to guard specifically on -dynlink mode, allowing
the optimization in more cases (-shared but not -dynlink build
modes).
Updates #58826.
Change-Id: I1391db6a33e8d0455a304e7cae7fcfdeb49bfdab
Reviewed-on: https://go-review.googlesource.com/c/go/+/473999
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Adds:
GOEXPERIMENT=loopvar (expected way of invoking)
-d=loopvar={-1,0,1,2,11,12} (for per-package control and/or logging)
-d=loopvarhash=... (for hash debugging)
loopvar=11,12 are for testing, benchmarking, and debugging.
If enabled,for loops of the form `for x,y := range thing`, if x and/or
y are addressed or captured by a closure, are transformed by renaming
x/y to a temporary and prepending an assignment to the body of the
loop x := tmp_x. This changes the loop semantics by making each
iteration's instance of x be distinct from the others (currently they
are all aliased, and when this matters, it is almost always a bug).
3-range with captured iteration variables are also transformed,
though it is a more complex transformation.
"Optimized" to do a simpler transformation for
3-clause for where the increment is empty.
(Prior optimization of address-taking under Return disabled, because
it was incorrect; returns can have loops for children. Restored in
a later CL.)
Includes support for -d=loopvarhash=<binary string> intended for use
with hash search and GOCOMPILEDEBUG=loopvarhash=<binary string>
(use `gossahash -e loopvarhash command-that-fails`).
Minor feature upgrades to hash-triggered features; clients can specify
that file-position hashes use only the most-inline position, and/or that
they use only the basenames of source files (not the full directory path).
Most-inlined is the right choice for debugging loop-iteration change
once the semantics are linked to the package across inlining; basename-only
makes it tractable to write tests (which, otherwise, depend on the full
pathname of the source file and thus vary).
Updates #57969.
Change-Id: I180a51a3f8d4173f6210c861f10de23de8a1b1db
Reviewed-on: https://go-review.googlesource.com/c/go/+/411904
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As described here:
https://github.com/golang/go/issues/31636#issuecomment-493271830
"Find the lexically earliest package that is not initialized yet,
but has had all its dependencies initialized, initialize that package,
and repeat."
Simplify the runtime a bit, by just computing the ordering required
in the linker and giving a list to the runtime.
Update #31636Fixes#57411
RELNOTE=yes
Change-Id: I1e4d3878ebe6e8953527aedb730824971d722cac
Reviewed-on: https://go-review.googlesource.com/c/go/+/462035
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A 0-sized no-op shouldn't prevent us from detecting that the first
instruction is from an inlined callee.
Update #58300
Change-Id: Ic5f6ed108c54a32c05e9b2264b516f2cc17e4619
Reviewed-on: https://go-review.googlesource.com/c/go/+/467977
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The assertion here was to make sure the newly constructed and
typechecked expression selected the same receiver-qualified method,
but in the case of anonymous receiver types we can actually end up
with separate types.Field instances corresponding to each types.Type
instance. In that case, the assertion spuriously failed.
The fix here is to relax and assertion and just compare the method's
name and type (including receiver type).
Fixes#58563.
Change-Id: I67d51ddb020e6ed52671473c93fc08f283a40886
Reviewed-on: https://go-review.googlesource.com/c/go/+/471676
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On Arm64, all 32-bit instructions will ignore the upper 32 bits and
clear them to zero for the result. No need to do an unsign extend before
a 32 bit op.
This CL removes the redundant unsign extension only for the existing
32-bit opcodes, and also omits the sign extension when the upper bit of
the result can be predicted.
Fixes#42162
Change-Id: I61e6670bfb8982572430e67a4fa61134a3ea240a
CustomizedGitHooks: yes
Reviewed-on: https://go-review.googlesource.com/c/go/+/427454
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Eric Fang <eric.fang@arm.com>
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As motivated on the issue, we want to move the functionality of the
run.go program to happen via a normal go test. Each .go test case in
the GOROOT/test directory gets a subtest, and cmd/go's support for
parallel test execution replaces run.go's own implementation thereof.
The goal of this change is to have fairly minimal and readable diff
while making an atomic changeover. The working directory is modified
during the test execution to be GOROOT/test as it was with run.go,
and most of the test struct and its run method are kept unchanged.
The next CL in the stack applies further simplifications and cleanups
that become viable.
There's no noticeable difference in test execution time: it takes around
60-80 seconds both before and after on my machine. Test caching, which
the previous runner lacked, can shorten the time significantly.
For #37486.
Fixes#56844.
Change-Id: I209619dc9d90e7529624e49c01efeadfbeb5c9ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/463276
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When inlining functions that contain function literals, we need to be
careful about position information. The OCLOSURE node should use the
inline-adjusted position, but the ODCLFUNC and its body should use the
original positions.
However, the same problem can arise with certain generic constructs,
which require the compiler to synthesize function literals to insert
dictionary arguments.
go.dev/cl/425395 fixed the issue with user-written function literals
in a somewhat kludgy way; this CL extends the same solution to
synthetic function literals.
This is all quite subtle and the solutions aren't terribly robust, so
longer term it's probably desirable to revisit how we track inlining
context for positions. But for now, this seems to be the least bad
solution, esp. for backporting to 1.20.
Updates #54625.
Fixes#58513.
Change-Id: Icc43a70dbb11a0e665cbc9e6a64ef274ad8253d1
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Some integer comparisons with 1 and -1 can be rewritten as comparisons
with 0. For example, x < 1 is equivalent to x <= 0. This is an
advantageous transformation on riscv64 because comparisons with zero
do not require a constant to be loaded into a register. Other
architectures will likely benefit too and the transformation is
relatively benign on architectures that do not benefit.
Change-Id: I2ce9821dd7605a660eb71d76e83a61f9bae1bf25
Reviewed-on: https://go-review.googlesource.com/c/go/+/350831
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For go/defer calls like "defer f(x, y)", the compiler rewrites it to:
x1, y1 := x, y
defer func() { f(x1, y1) }()
However, if "f" needs runtime type information, the "RType" field will
refer to the outer ".dict" param, causing wrong liveness analysis.
To fix this, if "f" refers to outer ".dict", the dict param will be
copied to an autotmp, and "f" will refer to this autotmp instead.
Fixes#58341
Change-Id: I238b6e75441442b5540d39bc818205398e80c94d
Reviewed-on: https://go-review.googlesource.com/c/go/+/466035
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