14 Commits

Author SHA1 Message Date
Aaron Ballman
84a3aadf0f Diagnose use of VLAs in C++ by default
Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 13:10:03 -04:00
Aaron Ballman
f5043f46c0 Revert "Diagnose use of VLAs in C++ by default"
This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm.org/buildbot/#/builders/164/builds/45262
2023-10-20 10:00:18 -04:00
Aaron Ballman
7339c0f782 Diagnose use of VLAs in C++ by default
Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 09:50:21 -04:00
Matt Arsenault
25bc999d1f Intrinsics: Add type overload to stacksave and stackstore
This allows use with non-0 address space stacks. llvm_ptr_ty should
never be used. This could use some more percolation up through mlir,
but this is enough to fix existing tests.

https://reviews.llvm.org/D156666
2023-08-09 18:33:11 -04:00
Sergei Barannikov
8be4bd16ca [clang] Convert remaining OpenMP tests to opaque pointers
Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D150733
2023-05-17 23:27:43 +03:00
Itay Bookstein
782c59a4ee [OpenMP] Prefix outlined and reduction func names with original func's name
This patch prefixes omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722
2023-04-19 23:00:26 +03:00
Itay Bookstein
6fdd13e0ec Revert "[OpenMP] Prefix outlined and reduction func names with original func's name"
This reverts commit 029bfc311d4d7d3cd90be81bb08c046848796d02.
2023-04-19 19:08:49 +03:00
Itay Bookstein
029bfc311d [OpenMP] Prefix outlined and reduction func names with original func's name
This patch attempts to prefix omp outlined helpers and reduction funcs
with the original function's name.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D140722
2023-04-19 19:05:21 +03:00
Dhruva Chakrabarti
839ac62c50 Revert "[OpenMP] Codegen aggregate for outlined function captures"
This reverts commit 7539e9cf811e590d9f12ae39673ca789e26386b4.
2022-09-15 03:08:46 +00:00
Giorgis Georgakoudis
7539e9cf81 [OpenMP] Codegen aggregate for outlined function captures
Parallel regions are outlined as functions with capture variables explicitly generated as distinct parameters in the function's argument list. That complicates the fork_call interface in the OpenMP runtime: (1) the fork_call is variadic since there is a variable number of arguments to forward to the outlined function, (2) wrapping/unwrapping arguments happens in the OpenMP runtime, which is sub-optimal, has been a source of ABI bugs, and has a hardcoded limit (16) in the number of arguments, (3)  forwarded arguments must cast to pointer types, which complicates debugging. This patch avoids those issues by aggregating captured arguments in a struct to pass to the fork_call.

Reviewed By: jdoerfert, jhuber6, ABataev

Differential Revision: https://reviews.llvm.org/D102107
2022-09-15 00:54:05 +00:00
Nicolai Hähnle
1ddc51d89d Inliner: don't mark call sites as 'nounwind' if that would be redundant
When F calls G calls H, G is nounwind, and G is inlined into F, then the
inlined call-site to H should be effectively nounwind so as not to lose
information during inlining.

If H itself is nounwind (which often happens when H is an intrinsic), we
no longer mark the callsite explicitly as nounwind. Previously, there
were cases where the inlined call-site of H differs from a pre-existing
call-site of H in F *only* in the explicitly added nounwind attribute,
thus preventing common subexpression elimination.

v2:
- just check CI->doesNotThrow

v3 (resubmit after revert at 344378808778c61d5599f4e0ac783ef7e6f8ed05):
- update Clang tests

Differential Revision: https://reviews.llvm.org/D129860
2022-07-20 14:17:23 +02:00
Nicolai Hähnle
3d2256cc75 Revert "Update some more tests with update_cc_test_checks.py"
This reverts commit 9fb33d52b045b6cc97f2f56fe5cd23b41de86ffe.

Buildbots are showing a number of regressions that don't reproduce
locally. Needs more investigating.
2022-07-19 16:39:57 +02:00
Nicolai Hähnle
9fb33d52b0 Update some more tests with update_cc_test_checks.py 2022-07-19 16:18:35 +02:00
Ritanya B Bharadwaj
8322fe200d Adding support for target in_reduction
Implementing target in_reduction by wrapping target task with host task with in_reduction and if clause. This is in compliance with OpenMP 5.0 section: 2.19.5.6.
So, this

```
  for (int i=0; i<N; i++) {
    res = res+i
  }
```

will become

```

   #pragma omp task in_reduction(+:res) if(0)
   #pragma omp target map(res)
   for (int i=0; i<N; i++) {
     res = res+i
   }
```

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D125669
2022-06-27 10:36:46 -05:00