set __NO_MATH_ERRNO__ if -fno-math-errno

This causes modern glibc to unset math_errhandling MATH_ERRNO. gcc 12
also sets some other macros, but most of them are associated with
flags ignored by clang, so without library examples, it is difficult to
determine whether they should be set. I think setting this one macro is
OK for now.

diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 629f991..ec40170 100644 (file)
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1039,6 +1039,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
 
   Builder.defineMacro("__USER_LABEL_PREFIX__", TI.getUserLabelPrefix());
 
+  if (!LangOpts.MathErrno)
+    Builder.defineMacro("__NO_MATH_ERRNO__");
+
   if (LangOpts.FastMath || LangOpts.FiniteMathOnly)
     Builder.defineMacro("__FINITE_MATH_ONLY__", "1");
   else

diff --git a/clang/test/Preprocessor/init-aarch64.c b/clang/test/Preprocessor/init-aarch64.c
index 3b6f4dd..8787d24 100644 (file)
--- a/clang/test/Preprocessor/init-aarch64.c
+++ b/clang/test/Preprocessor/init-aarch64.c
@@ -192,6 +192,7 @@
 // AARCH64-NEXT: #define __LONG_MAX__ 9223372036854775807L
 // AARCH64-NEXT: #define __LP64__ 1
 // AARCH64-NEXT: #define __NO_INLINE__ 1
+// AARCH64-NEXT: #define __NO_MATH_ERRNO__ 1
 // AARCH64-NEXT: #define __OBJC_BOOL_IS_BOOL 0
 // AARCH64-NEXT: #define __OPENCL_MEMORY_SCOPE_ALL_SVM_DEVICES 3
 // AARCH64-NEXT: #define __OPENCL_MEMORY_SCOPE_DEVICE 2

diff --git a/clang/test/Preprocessor/init.c b/clang/test/Preprocessor/init.c
index 7d83841..45d4941 100644 (file)
--- a/clang/test/Preprocessor/init.c
+++ b/clang/test/Preprocessor/init.c
@@ -1691,6 +1691,7 @@
 // WEBASSEMBLY64-NEXT:#define __LONG_MAX__ 9223372036854775807L
 // WEBASSEMBLY64-NEXT:#define __LP64__ 1
 // WEBASSEMBLY-NEXT:#define __NO_INLINE__ 1
+// WEBASSEMBLY-NEXT:#define __NO_MATH_ERRNO__ 1
 // WEBASSEMBLY-NEXT:#define __OBJC_BOOL_IS_BOOL 0
 // WEBASSEMBLY-NEXT:#define __OPENCL_MEMORY_SCOPE_ALL_SVM_DEVICES 3
 // WEBASSEMBLY-NEXT:#define __OPENCL_MEMORY_SCOPE_DEVICE 2

diff --git a/clang/test/Preprocessor/predefined-macros.c b/clang/test/Preprocessor/predefined-macros.c
index 2304eb8..0b67cbe 100644 (file)
--- a/clang/test/Preprocessor/predefined-macros.c
+++ b/clang/test/Preprocessor/predefined-macros.c
@@ -60,6 +60,15 @@
 // RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-FAST-MATH
 // CHECK-FAST-MATH: #define __FAST_MATH__ 1
 // CHECK-FAST-MATH: #define __FINITE_MATH_ONLY__ 1
+// CHECK-FAST-MATH: #define __NO_MATH_ERRNO__ 1
+//
+// RUN: %clang_cc1 %s -E -dM -fmath-errno -o - \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-MATH-ERRNO
+// CHECK-MATH-ERRNO-NOT: __NO_MATH_ERRNO__
+//
+// RUN: %clang %s -E -dM -fno-math-errno -o - \
+// RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-NO-MATH-ERRNO
+// CHECK-NO-MATH-ERRNO: #define __NO_MATH_ERRNO__ 1
 //
 // RUN: %clang_cc1 %s -E -dM -ffinite-math-only -o - \
 // RUN:   | FileCheck -match-full-lines %s --check-prefix=CHECK-FINITE-MATH-ONLY