X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FErrorHandling.h;h=95b01095c1b25c89ae98ad52a22cf60b6043e15f;hb=536a88ad5bf160232205192a7ce72e50bfadbded;hp=6a0b6a30bbd976dc40592dd2f7bbef2379787d05;hpb=19e57025d458d3cb50804fd821fd89b868a819bd;p=oota-llvm.git

diff --git a/include/llvm/Support/ErrorHandling.h b/include/llvm/Support/ErrorHandling.h
index 6a0b6a30bbd..95b01095c1b 100644
--- a/include/llvm/Support/ErrorHandling.h
+++ b/include/llvm/Support/ErrorHandling.h
@@ -16,6 +16,7 @@
 #define LLVM_SUPPORT_ERRORHANDLING_H
 
 #include "llvm/Support/Compiler.h"
+#include "llvm/ADT/StringRef.h"
 #include <string>
 
 namespace llvm {
@@ -74,6 +75,7 @@ namespace llvm {
   /// does not return.
   LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const char *reason);
   LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const std::string &reason);
+  LLVM_ATTRIBUTE_NORETURN void report_fatal_error(StringRef reason);
   LLVM_ATTRIBUTE_NORETURN void report_fatal_error(const Twine &reason);
 
   /// This function calls abort(), and prints the optional message to stderr.
@@ -84,16 +86,19 @@ namespace llvm {
                                                          unsigned line=0);
 }
 
-/// Prints the message and location info to stderr in !NDEBUG builds.
-/// This is intended to be used for "impossible" situations that imply
-/// a bug in the compiler.
+/// Marks that the current location is not supposed to be reachable.
+/// In !NDEBUG builds, prints the message and location info to stderr.
+/// In NDEBUG builds, becomes an optimizer hint that the current location
+/// is not supposed to be reachable.  On compilers that don't support
+/// such hints, prints a reduced message instead.
 ///
-/// In NDEBUG mode it only prints "UNREACHABLE executed".
-/// Use this instead of assert(0), so that the compiler knows this path
-/// is not reachable even for NDEBUG builds.
+/// Use this instead of assert(0).  It conveys intent more clearly and
+/// allows compilers to omit some unnecessary code.
 #ifndef NDEBUG
 #define llvm_unreachable(msg) \
   ::llvm::llvm_unreachable_internal(msg, __FILE__, __LINE__)
+#elif defined(LLVM_BUILTIN_UNREACHABLE)
+#define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE
 #else
 #define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal()
 #endif