[libc] Move __LLVM_LIBC__ define to __llvm-libc-common.h #126877
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Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting __LLVM_LIBC__. Since __llvm-libc-common.h is included from all libc headers, defining __LLVM_LIBC__ there ensures that this define is available whenever any of the standard header is included.
petrhosek
requested review from
frobtech,
nickdesaulniers,
jhuber6,
lntue and
michaelrj-google
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@llvm/pr-subscribers-libc Author: Petr Hosek (petrhosek) ChangesRelying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting LLVM_LIBC. Since __llvm-libc-common.h is included from all libc headers, defining LLVM_LIBC there ensures that this define is available whenever any of the standard header is included. Full diff: https://github.com/llvm/llvm-project/pull/126877.diff 2 Files Affected:
diff --git a/libc/include/__llvm-libc-common.h b/libc/include/__llvm-libc-common.h
index d3f8a4e63268a..a0fa506c01ab8 100644
--- a/libc/include/__llvm-libc-common.h
+++ b/libc/include/__llvm-libc-common.h
@@ -9,6 +9,8 @@
#ifndef LLVM_LIBC_COMMON_H
#define LLVM_LIBC_COMMON_H
+#define __LLVM_LIBC__ 1
+
#ifdef __cplusplus
#undef __BEGIN_C_DECLS
diff --git a/libc/include/llvm-libc-macros/features-macros.h b/libc/include/llvm-libc-macros/features-macros.h
index 5bc87a68fc0ba..f87ae4ad12408 100644
--- a/libc/include/llvm-libc-macros/features-macros.h
+++ b/libc/include/llvm-libc-macros/features-macros.h
@@ -9,6 +9,4 @@
#ifndef LLVM_LIBC_MACROS_FEATURES_MACROS_H
#define LLVM_LIBC_MACROS_FEATURES_MACROS_H
-#define __LLVM_LIBC__ 1
-
#endif // LLVM_LIBC_MACROS_FEATURES_MACROS_H
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I'm okay with this, but including |
It will since |
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/cherry-pick b0d7820 |
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/pull-request #126960 |
flovent
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Feb 13, 2025
Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting __LLVM_LIBC__. Since __llvm-libc-common.h is included from all libc headers, defining __LLVM_LIBC__ there ensures that this define is available whenever any of the standard header is included.
| @@ -9,6 +9,4 @@ | |||
| #ifndef LLVM_LIBC_MACROS_FEATURES_MACROS_H | |||
| #define LLVM_LIBC_MACROS_FEATURES_MACROS_H | |||
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| #define __LLVM_LIBC__ 1 | |||
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perhaps we should have just deleted this file? It's literally only now empty header guards.
joaosaffran
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Feb 14, 2025
Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting __LLVM_LIBC__. Since __llvm-libc-common.h is included from all libc headers, defining __LLVM_LIBC__ there ensures that this define is available whenever any of the standard header is included.
redstar
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Feb 14, 2025
Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting __LLVM_LIBC__. Since __llvm-libc-common.h is included from all libc headers, defining __LLVM_LIBC__ there ensures that this define is available whenever any of the standard header is included. (cherry picked from commit b0d7820)
sivan-shani
pushed a commit
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that referenced
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Feb 24, 2025
Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting __LLVM_LIBC__. Since __llvm-libc-common.h is included from all libc headers, defining __LLVM_LIBC__ there ensures that this define is available whenever any of the standard header is included.
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Relying on features.h is problematic since codebases are free to have such a header on their search path, which breaks compilation. libc should instead provide a more standard way of getting LLVM_LIBC. Since __llvm-libc-common.h is included from all libc headers, defining LLVM_LIBC there ensures that this define is available whenever any of the standard header is included.