diff options
Diffstat (limited to 'include/llvm/Support/ErrorHandling.h')
| -rw-r--r-- | include/llvm/Support/ErrorHandling.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/include/llvm/Support/ErrorHandling.h b/include/llvm/Support/ErrorHandling.h index fb0c88d8d8..95b01095c1 100644 --- a/include/llvm/Support/ErrorHandling.h +++ b/include/llvm/Support/ErrorHandling.h @@ -86,18 +86,21 @@ 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__) -#else +#elif defined(LLVM_BUILTIN_UNREACHABLE) #define llvm_unreachable(msg) LLVM_BUILTIN_UNREACHABLE +#else +#define llvm_unreachable(msg) ::llvm::llvm_unreachable_internal() #endif #endif |