Fix and simplify __has_builtin conditions (#73905)

dotnet · Aug 14, 2022 · c2531ed · c2531ed
1 parent 7d986fa
commit c2531ed
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Showing 4 changed files with 13 additions and 34 deletions.
diff --git a/src/coreclr/gc/env/gcenv.base.h b/src/coreclr/gc/env/gcenv.base.h
@@ -45,6 +45,10 @@
 #define SSIZE_T_MAX ((ptrdiff_t)(SIZE_T_MAX / 2))
 #endif
 
+#ifndef __has_builtin
+#define __has_builtin(x) 0
+#endif
+
 #ifndef _INC_WINDOWS
 // -----------------------------------------------------------------------------------------------------------
 //
@@ -186,26 +190,15 @@ typedef DWORD (WINAPI *PTHREAD_START_ROUTINE)(void* lpThreadParameter);
  #endif
 #else // _MSC_VER
 
-#ifdef __llvm__
-#define HAS_IA32_PAUSE __has_builtin(__builtin_ia32_pause)
-#define HAS_IA32_MFENCE __has_builtin(__builtin_ia32_mfence)
-#else
-#define HAS_IA32_PAUSE 0
-#define HAS_IA32_MFENCE 0
-#endif
-
-// Only clang defines __has_builtin, so we first test for a GCC define
-// before using __has_builtin.
-
 #if defined(__i386__) || defined(__x86_64__)
 
-#if (__GNUC__ > 4 && __GNUC_MINOR > 7) || HAS_IA32_PAUSE
+#if __has_builtin(__builtin_ia32_pause)
  // clang added this intrinsic in 3.8
  // gcc added this intrinsic by 4.7.1
  #define YieldProcessor __builtin_ia32_pause
 #endif // __has_builtin(__builtin_ia32_pause)
 
-#if defined(__GNUC__) || HAS_IA32_MFENCE
+#if __has_builtin(__builtin_ia32_mfence)
  // clang has had this intrinsic since at least 3.0
  // gcc has had this intrinsic since forever
  #define MemoryBarrier __builtin_ia32_mfence

diff --git a/src/coreclr/gc/unix/gcenv.unix.cpp b/src/coreclr/gc/unix/gcenv.unix.cpp
@@ -584,12 +584,6 @@ void GCToOSInterface::FlushProcessWriteBuffers()
 // otherwise raises a SIGTRAP.
 void GCToOSInterface::DebugBreak()
 {
-    // __has_builtin is only defined by clang. GCC doesn't have a debug
-    // trap intrinsic anyway.
-#ifndef __has_builtin
- #define __has_builtin(x) 0
-#endif // __has_builtin
-
 #if __has_builtin(__builtin_debugtrap)
     __builtin_debugtrap();
 #else

diff --git a/src/coreclr/nativeaot/Runtime/unix/PalRedhawkUnix.cpp b/src/coreclr/nativeaot/Runtime/unix/PalRedhawkUnix.cpp
@@ -1039,10 +1039,6 @@ REDHAWK_PALEXPORT uint32_t REDHAWK_PALAPI PalCompatibleWaitAny(UInt32_BOOL alert
     return WaitForSingleObjectEx(pHandles[0], timeout, alertable);
 }
 
-#ifndef __has_builtin
-#define __has_builtin(x) 0
-#endif
-
 #if !__has_builtin(_mm_pause)
 extern "C" void _mm_pause()
 // Defined for implementing PalYieldProcessor in PalRedhawk.h

diff --git a/src/coreclr/pal/inc/pal.h b/src/coreclr/pal/inc/pal.h
@@ -4285,15 +4285,11 @@ inline WCHAR *PAL_wcsstr(WCHAR* S, const WCHAR* P)
 }
 #endif
 
-#if defined(__llvm__)
-#define HAS_ROTL __has_builtin(_rotl)
-#define HAS_ROTR __has_builtin(_rotr)
-#else
-#define HAS_ROTL 0
-#define HAS_ROTR 0
+#ifndef __has_builtin
+#define __has_builtin(x) 0
 #endif
 
-#if !HAS_ROTL
+#if !__has_builtin(_rotl)
 /*++
 Function:
 _rotl
@@ -4311,14 +4307,14 @@ unsigned int __cdecl _rotl(unsigned int value, int shift)
     retval = (value << shift) | (value >> (sizeof(int) * CHAR_BIT - shift));
     return retval;
 }
-#endif // !HAS_ROTL
+#endif // !__has_builtin(_rotl)
 
 // On 64 bit unix, make the long an int.
 #ifdef HOST_64BIT
 #define _lrotl _rotl
-#endif // HOST_64BIT
+#endif
 
-#if !HAS_ROTR
+#if !__has_builtin(_rotr)
 
 /*++
 Function:
@@ -4338,7 +4334,7 @@ unsigned int __cdecl _rotr(unsigned int value, int shift)
     return retval;
 }
 
-#endif // !HAS_ROTR
+#endif // !__has_builtin(_rotr)
 
 PALIMPORT int __cdecl abs(int);
 // clang complains if this is declared with __int64