From c670cdb968609d57dd490075cd3567402bba8eed Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Sun, 5 Nov 2023 23:22:56 +0000
Subject: [PATCH] [sanitizers] Do not define __has_feature in
 sanitizer/common_interface_defs.h (#66628)

Public headers intended for user code should not define `__has_feature`,
because this can break preprocessor checks done later in user code, e.g.
if they test `#ifdef __has_feature` to check for real support in the
compiler.

Replace the only use in the public header with a check for it being
supported before trying to use it. Define the fallback definition in the
internal headers, so that other internal sanitizer headers can continue
to use it as preferred.

This resolves a bug reported to GCC as https://gcc.gnu.org/PR109882
---
 compiler-rt/include/sanitizer/asan_interface.h        | 11 ++++++++++-
 compiler-rt/include/sanitizer/common_interface_defs.h |  5 -----
 .../lib/sanitizer_common/sanitizer_internal_defs.h    |  5 +++++
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/compiler-rt/include/sanitizer/asan_interface.h b/compiler-rt/include/sanitizer/asan_interface.h
index de3ea3ddb440..37b6d08f4db1 100644
--- a/compiler-rt/include/sanitizer/asan_interface.h
+++ b/compiler-rt/include/sanitizer/asan_interface.h
@@ -50,7 +50,15 @@ void SANITIZER_CDECL __asan_unpoison_memory_region(void const volatile *addr,
                                                    size_t size);
 
 // Macros provided for convenience.
-#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
+#ifdef __has_feature
+#if __has_feature(address_sanitizer)
+#define ASAN_DEFINE_REGION_MACROS
+#endif
+#elif defined(__SANITIZE_ADDRESS__)
+#define ASAN_DEFINE_REGION_MACROS
+#endif
+
+#ifdef ASAN_DEFINE_REGION_MACROS
 /// Marks a memory region as unaddressable.
 ///
 /// \note Macro provided for convenience; defined as a no-op if ASan is not
@@ -74,6 +82,7 @@ void SANITIZER_CDECL __asan_unpoison_memory_region(void const volatile *addr,
 #define ASAN_POISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
 #define ASAN_UNPOISON_MEMORY_REGION(addr, size) ((void)(addr), (void)(size))
 #endif
+#undef ASAN_DEFINE_REGION_MACROS
 
 /// Checks if an address is poisoned.
 ///
diff --git a/compiler-rt/include/sanitizer/common_interface_defs.h b/compiler-rt/include/sanitizer/common_interface_defs.h
index 5a78bb1a23a2..56d9e008fa06 100644
--- a/compiler-rt/include/sanitizer/common_interface_defs.h
+++ b/compiler-rt/include/sanitizer/common_interface_defs.h
@@ -15,11 +15,6 @@
 #include <stddef.h>
 #include <stdint.h>
 
-// GCC does not understand __has_feature.
-#if !defined(__has_feature)
-#define __has_feature(x) 0
-#endif
-
 // Windows allows a user to set their default calling convention, but we always
 // use __cdecl
 #ifdef _WIN32
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
index 552d65067944..3809669dd48b 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_internal_defs.h
@@ -15,6 +15,11 @@
 #include "sanitizer_platform.h"
 #include "sanitizer_redefine_builtins.h"
 
+// GCC does not understand __has_feature.
+#if !defined(__has_feature)
+#define __has_feature(x) 0
+#endif
+
 #ifndef SANITIZER_DEBUG
 # define SANITIZER_DEBUG 0
 #endif