Commit Graph

10 Commits

Author SHA1 Message Date
Fangrui Song dbc96b518b Revert "[CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition"
This reverts commit 789a46f2d7.

Accidentally committed.
2020-02-03 10:09:39 -08:00
Fangrui Song 789a46f2d7 [CodeGenModule] Assume dso_local for -fpic -fno-semantic-interposition
Summary:
Clang -fpic defaults to -fno-semantic-interposition (GCC -fpic defaults
to -fsemantic-interposition).
Users need to specify -fsemantic-interposition to get semantic
interposition behavior.

Semantic interposition is currently a best-effort feature. There may
still be some cases where it is not handled well.

Reviewers: peter.smith, rnk, serge-sans-paille, sfertile, jfb, jdoerfert

Subscribers: dschuff, jyknight, dylanmckay, nemanjai, jvesely, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, arphaman, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D73865
2020-02-03 09:52:48 -08:00
Hans Wennborg a9e5d2f35d Re-commit r357452 (take 3): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"
Third time's the charm.

This was reverted in r363220 due to being suspected of an internal benchmark
regression and a test failure, none of which turned out to be caused by this.

llvm-svn: 363529
2019-06-17 07:47:28 +00:00
David L. Jones c73fadaa84 Revert r361811: 'Re-commit r357452 (take 2): "SimplifyCFG SinkCommonCodeFromPredecessors ...'
We have observed some failures with internal builds with this revision.

- Performance regressions:
  - llvm's SingleSource/Misc evalloop shows performance regressions (although these may be red herrings).
  - Benchmarks for Abseil's SwissTable.
- Correctness:
  - Failures for particular libicu tests when building the Google AppEngine SDK (for PHP).

hwennborg has already been notified, and is aware of reproducer failures.

llvm-svn: 363220
2019-06-13 02:04:45 +00:00
Hans Wennborg d936e40575 Re-commit r357452 (take 2): "SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"
This was reverted in r360086 as it was supected of causing mysterious test
failures internally. However, it was never concluded that this patch was the
root cause.

> The code was previously checking that candidates for sinking had exactly
> one use or were a store instruction (which can't have uses). This meant
> we could sink call instructions only if they had a use.
>
> That limitation seemed a bit arbitrary, so this patch changes it to
> "instruction has zero or one use" which seems more natural and removes
> the need to special-case stores.
>
> Differential revision: https://reviews.llvm.org/D59936

llvm-svn: 361811
2019-05-28 12:19:38 +00:00
Jordan Rupprecht 8f14e7cacf Revert "Re-commit r357452: SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)"
This reverts r357452 (git commit 21eb771dcb).

This was causing strange optimization-related test failures on an internal test. Will followup with more details offline.

llvm-svn: 360086
2019-05-06 21:55:05 +00:00
Hans Wennborg 21eb771dcb Re-commit r357452: SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)
The original commit caused false positives from AddressSanitizer's
use-after-scope checks, which have now been fixed in r358478.

> The code was previously checking that candidates for sinking had exactly
> one use or were a store instruction (which can't have uses). This meant
> we could sink call instructions only if they had a use.
>
> That limitation seemed a bit arbitrary, so this patch changes it to
> "instruction has zero or one use" which seems more natural and removes
> the need to special-case stores.
>
> Differential revision: https://reviews.llvm.org/D59936

llvm-svn: 358483
2019-04-16 12:13:25 +00:00
David L. Jones 8b8a02175a Revert r357452 - 'SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)'
This revision causes tests to fail under ASAN. Since the cause of the failures
is not clear (could be ASAN, could be a Clang bug, could be a bug in this
revision), the safest course of action seems to be to revert while investigating.

llvm-svn: 357667
2019-04-04 02:27:57 +00:00
Hans Wennborg b669fea42f SimplifyCFG SinkCommonCodeFromPredecessors: Also sink function calls without used results (PR41259)
The code was previously checking that candidates for sinking had exactly
one use or were a store instruction (which can't have uses). This meant
we could sink call instructions only if they had a use.

That limitation seemed a bit arbitrary, so this patch changes it to
"instruction has zero or one use" which seems more natural and removes
the need to special-case stores.

Differential revision: https://reviews.llvm.org/D59936

llvm-svn: 357452
2019-04-02 08:01:38 +00:00
George Burgess IV 003be7cbf4 [CodeGen] Emit lifetime.ends in both EH and non-EH blocks
Before this, we'd only emit lifetime.ends for these temps in
non-exceptional paths. This potentially made our stack larger than it
needed to be for any code that follows an EH cleanup. e.g. in

```
struct Foo { char cs[32]; };

void escape(void *);

struct Bar { ~Bar() { char cs[64]; escape(cs); } };

Foo getFoo();

void baz() {
  Bar b;
  getFoo();
}
```

baz() would require 96 bytes of stack, since the temporary from getFoo()
only had a lifetime.end on the non-exceptional path.

This also makes us keep hold of the Value* returned by
EmitLifetimeStart, so we don't have to remake it later.

llvm-svn: 326988
2018-03-08 05:32:30 +00:00