[llvm-branch-commits] [clang] 7db2e33 - [Clang] Define `__SIG_ATOMIC_TYPE__` macro (#213934)

[Douglas Yung via llvm-branch-commits]

Author: Zeyi Xu
Date: 2026-08-06T00:46:27Z
New Revision: 7db2e3307ce6a8bcc0f20caa16e1fd031013281f

URL: https://github.com/llvm/llvm-project/commit/7db2e3307ce6a8bcc0f20caa16e1fd031013281f
DIFF: https://github.com/llvm/llvm-project/commit/7db2e3307ce6a8bcc0f20caa16e1fd031013281f.diff

LOG: [Clang] Define `__SIG_ATOMIC_TYPE__` macro (#213934)

Define `__SIG_ATOMIC_TYPE__` for compatibility with GCC.

This fixes `riscv32-netbsd` and `riscv64-netbsd` system headers that
define `sig_atomic_t` using this macro.

Reference:
https://gcc.gnu.org/onlinedocs/gcc-16.1.0/cpp/Common-Predefined-Macros.html

Follow up of #199678, Closes #213895

(cherry picked from commit c08ed4c1ab086aad6f22cfc499e74d92953045ae)

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.md
    clang/lib/Frontend/InitPreprocessor.cpp
    clang/test/Preprocessor/init-aarch64.c
    clang/test/Preprocessor/init-riscv.c
    clang/test/Preprocessor/init.c

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.md b/clang/docs/ReleaseNotes.md
index 937db9730a001..a75d666f67691 100644
--- a/clang/docs/ReleaseNotes.md
+++ b/clang/docs/ReleaseNotes.md
@@ -834,6 +834,7 @@ latest release, please see the [Clang Web Site](https://clang.llvm.org) or the
 - Fixed a crash in the constant evaluator when an ill-formed array new-expression whose bound could not be determined (e.g. `new int[]()`) was used in a constant expression. (#GH200139)
 - Fixed a case where function effect analysis (`nonblocking` etc.) did not visit a destructor invoked from a `delete` expression. (#GH184460)
 - Clang now defines the GCC-compatible predefined macros `__WCHAR_MIN__`, `__WINT_MIN__`, and `__SIG_ATOMIC_MIN__`. (#GH199678)
+- Clang now defines the GCC-compatible predefined macro `__SIG_ATOMIC_TYPE__`. (#GH213895)
 - Fix a crash in addUnsizedArray due assert not verifying we have a Base before doing checks on it. (#GH44212)
 - Fixed an assertion that could occur when rebuilding parenthesized list initialization expressions during template instantiation or AST transformation.
 

diff  --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 8b6ff844d0daa..65b065dc818f5 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1191,6 +1191,7 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   DefineFmt(LangOpts, "__SIZE", TI.getSizeType(), TI, Builder);
   DefineType("__WCHAR_TYPE__", TI.getWCharType(), Builder);
   DefineType("__WINT_TYPE__", TI.getWIntType(), Builder);
+  DefineType("__SIG_ATOMIC_TYPE__", TI.getSigAtomicType(), Builder);
   DefineTypeSizeAndWidth("__SIG_ATOMIC", TI.getSigAtomicType(), TI, Builder);
   DefineTypeMin("__SIG_ATOMIC", TI.getSigAtomicType(), TI, Builder);
   if (LangOpts.C23)

diff  --git a/clang/test/Preprocessor/init-aarch64.c b/clang/test/Preprocessor/init-aarch64.c
index 6796cb3bdd912..44b92ea2331b0 100644
--- a/clang/test/Preprocessor/init-aarch64.c
+++ b/clang/test/Preprocessor/init-aarch64.c
@@ -264,6 +264,7 @@
 // AARCH64-NEXT: #define __SHRT_WIDTH__ 16
 // AARCH64-NEXT: #define __SIG_ATOMIC_MAX__ 2147483647
 // AARCH64-NEXT: #define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
+// AARCH64-NEXT: #define __SIG_ATOMIC_TYPE__ int
 // AARCH64-NEXT: #define __SIG_ATOMIC_WIDTH__ 32
 // AARCH64-NEXT: #define __SIZEOF_DOUBLE__ 8
 // AARCH64-NEXT: #define __SIZEOF_FLOAT__ 4

diff  --git a/clang/test/Preprocessor/init-riscv.c b/clang/test/Preprocessor/init-riscv.c
index 00282e670a0f7..ad554e6948a87 100644
--- a/clang/test/Preprocessor/init-riscv.c
+++ b/clang/test/Preprocessor/init-riscv.c
@@ -14,5 +14,6 @@
 // RV64: #define __GCC_DESTRUCTIVE_SIZE 64
 
 // NETBSD: #define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
+// NETBSD: #define __SIG_ATOMIC_TYPE__ int
 // NETBSD: #define __WCHAR_MIN__ (-__WCHAR_MAX__ - 1)
 // NETBSD: #define __WINT_MIN__ 0U

diff  --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index 1d49af5c8d62f..29a8d234ece49 100644
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1950,9 +1950,11 @@
 // WEBASSEMBLY-NEXT:#define __SHRT_WIDTH__ 16
 // WEBASSEMBLY32-NEXT:#define __SIG_ATOMIC_MAX__ 2147483647L
 // WEBASSEMBLY32-NEXT:#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
+// WEBASSEMBLY32-NEXT:#define __SIG_ATOMIC_TYPE__ long int
 // WEBASSEMBLY32-NEXT:#define __SIG_ATOMIC_WIDTH__ 32
 // WEBASSEMBLY64-NEXT:#define __SIG_ATOMIC_MAX__ 9223372036854775807L
 // WEBASSEMBLY64-NEXT:#define __SIG_ATOMIC_MIN__ (-__SIG_ATOMIC_MAX__ - 1)
+// WEBASSEMBLY64-NEXT:#define __SIG_ATOMIC_TYPE__ long int
 // WEBASSEMBLY64-NEXT:#define __SIG_ATOMIC_WIDTH__ 64
 // WEBASSEMBLY-NEXT:#define __SIZEOF_DOUBLE__ 8
 // WEBASSEMBLY-NEXT:#define __SIZEOF_FLOAT__ 4