Commit Graph

3 Commits

Author SHA1 Message Date
Aaron Ballman e765e0bc8e Use functions with prototypes when appropriate; NFC
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,

  void func();

becomes

  void func(void);

This is the first batch of tests being updated (there are a significant
number of other tests left to be updated).
2022-02-03 16:42:27 -05:00
Kai Luo 6ea2431d3f [clang][compiler-rt][atomics] Add `__c11_atomic_fetch_nand` builtin and support `__atomic_fetch_nand` libcall
Add `__c11_atomic_fetch_nand` builtin to language extensions and support `__atomic_fetch_nand` libcall in compiler-rt.

Reviewed By: theraven

Differential Revision: https://reviews.llvm.org/D112400
2021-10-28 02:18:43 +00:00
JF Bastien e77b48b078 Implement -Watomic-implicit-seq-cst
Summary:
_Atomic and __sync_* operations are implicitly sequentially-consistent. Some
codebases want to force explicit usage of memory order instead. This warning
allows them to know where implicit sequentially-consistent memory order is used.
The warning isn't on by default because _Atomic was purposefully designed to
have seq_cst as the default: the idea was that it's the right thing to use most
of the time. This warning allows developers who disagree to enforce explicit
usage instead.

A follow-up patch will take care of C++'s std::atomic. It'll be different enough
from this patch that I think it should be separate: for C++ the atomic
operations all have a memory order parameter (or two), but it's defaulted. I
believe this warning should trigger when the default is used, but not when
seq_cst is used explicitly (or implicitly as the failure order for cmpxchg).

<rdar://problem/28172966>

Reviewers: rjmccall

Subscribers: dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51084

llvm-svn: 341860
2018-09-10 20:42:56 +00:00