[llvm-commits] [llvm] r127608 - in /llvm/trunk/include/llvm/Support: Compiler.h ErrorHandling.h

[John McCall]

Author: rjmccall
Date: Mon Mar 14 15:01:21 2011
New Revision: 127608

URL: http://llvm.org/viewvc/llvm-project?rev=127608&view=rev
Log:
Make llvm_unreachable evaluate to __builtin_unreachable() in -Asserts
builds, which was the apparent consensus of PR8973 and llvmdev.


Modified:
    llvm/trunk/include/llvm/Support/Compiler.h
    llvm/trunk/include/llvm/Support/ErrorHandling.h

Modified: llvm/trunk/include/llvm/Support/Compiler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=127608&r1=127607&r2=127608&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Compiler.h (original)
+++ llvm/trunk/include/llvm/Support/Compiler.h Mon Mar 14 15:01:21 2011
@@ -126,4 +126,19 @@
   decl
 #endif
 
+// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
+// to an expression which states that it is undefined behavior for the
+// compiler to reach this point.
+#if defined(__clang__) || (__GNUC__ > 4) \
+ || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
+# define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
+#else
+#ifdef __cplusplus
+extern "C" LLVM_ATTRIBUTE_NORETURN void abort();
+#else
+extern LLVM_ATTRIBUTE_NORETURN void abort();
+#endif
+# define LLVM_BUILTIN_UNREACHABLE abort()
+#endif
+
 #endif

Modified: llvm/trunk/include/llvm/Support/ErrorHandling.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ErrorHandling.h?rev=127608&r1=127607&r2=127608&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ErrorHandling.h (original)
+++ llvm/trunk/include/llvm/Support/ErrorHandling.h Mon Mar 14 15:01:21 2011
@@ -97,7 +97,7 @@
 #define llvm_unreachable(msg) \
   ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__)
 #else
-#define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal()
+#define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE
 #endif
 
 #endif