assert(0) -> LLVM_UNREACHABLE.

Make llvm_unreachable take an optional string, thus moving the cerr<< out of
line.
LLVM_UNREACHABLE is now a simple wrapper that makes the message go away for
NDEBUG builds.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75379 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/ErrorHandling.h

@@ -46,11 +46,11 @@ namespace llvm {
   /// This function calls abort().
   /// Call this after assert(0), so that compiler knows the path is not
   /// reachable.
-  void llvm_unreachable(void) NORETURN;
+  void llvm_unreachable(const char *msg=0) NORETURN;
 }
 
 #ifndef NDEBUG
-#define LLVM_UNREACHABLE(msg) do {cerr<<msg<<"\n";llvm_unreachable();}while(0)
+#define LLVM_UNREACHABLE(msg) llvm_unreachable(msg)
 #else
 #define LLVM_UNREACHABLE(msg) llvm_unreachable()
 #endif

include/llvm/Support/InstVisitor.h

@@ -14,6 +14,7 @@
 #include "llvm/Function.h"
 #include "llvm/Instructions.h"
 #include "llvm/Module.h"
+#include "llvm/Support/ErrorHandling.h"
 
 namespace llvm {
 
@@ -113,8 +114,7 @@ public:
   //
   RetTy visit(Instruction &I) {
     switch (I.getOpcode()) {
-    default: assert(0 && "Unknown instruction type encountered!");
-             abort();
+    default: LLVM_UNREACHABLE("Unknown instruction type encountered!");
       // Build the switch statement using the Instruction.def file...
 #define HANDLE_INST(NUM, OPCODE, CLASS) \
     case Instruction::OPCODE: return \

include/llvm/Support/PassNameParser.h

@@ -24,6 +24,7 @@
 #define LLVM_SUPPORT_PASS_NAME_PARSER_H
 
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Pass.h"
 #include <algorithm>
 #include <cstring>
@@ -67,7 +68,7 @@ public:
     if (findOption(P->getPassArgument()) != getNumOptions()) {
       cerr << "Two passes with the same argument (-"
            << P->getPassArgument() << ") attempted to be registered!\n";
-      abort();
+      llvm_unreachable();
     }
     addLiteralOption(P->getPassArgument(), P, P->getPassName());
   }