5 Commits

Author SHA1 Message Date
Thurston Dang
9c0606a08b
Reapply "[ubsan] Connect -fsanitize-skip-hot-cutoff to LowerAllowCheckPass<cutoffs>" (#125032) (#125037)
This reverts commit 928cad49beec0120686478f502899222e836b545 i.e.,
relands dccd27112722109d2e2f03e8da9ce8690f06e11b, with a fix to avoid
use-after-scope by changing the lambda to capture by value.
2025-01-30 09:37:16 -08:00
Thurston Dang
928cad49be
Revert "[ubsan] Connect -fsanitize-skip-hot-cutoff to LowerAllowCheckPass<cutoffs>" (#125032)
Reverts llvm/llvm-project#124857 due to buildbot breakage
(https://lab.llvm.org/buildbot/#/builders/46/builds/11310)
2025-01-29 22:03:05 -08:00
Thurston Dang
dccd271127
[ubsan] Connect -fsanitize-skip-hot-cutoff to LowerAllowCheckPass<cutoffs> (#124857)
This adds the plumbing between -fsanitize-skip-hot-cutoff (introduced in
https://github.com/llvm/llvm-project/pull/121619) and
LowerAllowCheckPass<cutoffs> (introduced in
https://github.com/llvm/llvm-project/pull/124211).
    
The net effect is that -fsanitize-skip-hot-cutoff now combines the
functionality of -ubsan-guard-checks and
-lower-allow-check-percentile-cutoff (though this patch does not remove
those yet), and generalizes the latter to allow per-sanitizer cutoffs.
    
Note: this patch replaces Intrinsic::allow_ubsan_check's
SanitizerHandler parameter with SanitizerOrdinal; this is necessary
because the hot cutoffs are specified in terms of SanitizerOrdinal
(e.g., null, alignment), not SanitizerHandler (e.g., TypeMismatch).
Likewise, CodeGenFunction::EmitCheck is changed to emit
allow_ubsan_check() for each individual check.

---------

Co-authored-by: Vitaly Buka <vitalybuka@gmail.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>
2025-01-29 21:03:26 -08:00
Vitaly Buka
7787328dd6
[ubsan] Improve lowering of @llvm.allow.ubsan.check (#119013)
This fix the case, when single hot inlined callsite, prevent
checks for all other. This helps to reduce number of removed checks up
to 50% (deppedes on `cutoff-hot` value) .

`ScalarOptimizerLateEPCallback` was happening during
CGSCC walk, after each inlining, but this is effectively
after inlining.

Example, order in comments:

```
static void overflow() {
  // 1. Inline get/set if possible
  // 2. Simplify
  // 3. LowerAllowCheckPass
  set(get() + get());
}

void test() {
  // 4. Inline
  // 5. Nothing for LowerAllowCheckPass
  overflow();
}
```

With this patch it will look like:
```
static void overflow() {
  // 1. Inline get/set if possible
  // 2. Simplify
  set(get() + get());
}

void test() {
  // 3. Inline
  // 4. Simplify
  overflow();
}

// Later, after inliner CGSCC walk complete:
// 5. LowerAllowCheckPass for `overflow`
// 6. LowerAllowCheckPass for `test`
```
2024-12-07 16:12:58 -08:00
Vitaly Buka
66f9448b4b
[NFC][ubsan] Pre-commit test with missed optimization (#119012) 2024-12-07 14:50:19 -08:00