Fix pnacl-sz to return with staus 0 in report_fatal_error.

src/IceCompileServer.cpp

Index: src/IceCompileServer.cpp
diff --git a/src/IceCompileServer.cpp b/src/IceCompileServer.cpp
index db0694b9556653f230c8af08b6271dd2baff9f69..f0ae43a2273eda525e6806721b316082018c5afe 100644
--- a/src/IceCompileServer.cpp
+++ b/src/IceCompileServer.cpp
@@ -93,6 +93,30 @@ ErrorCodes getReturnValue(const Ice::ClFlagsExtra &Flags, ErrorCodes Val) {
   return Val;
 }
 
+// Reports fatal error message, and then exits with success status 0.
+void reportFatalErrorThenExitSuccess(void *UserData,
+                                     const std::string &Reason,
+                                     bool gen_crash_diag) {

[Jim Stichnoth, 2015/09/30 21:32:13]

Should probably be GenCrashDiag or something.

But given that this arg isn't actually used, I'm surprised no "unused parameter"
error is being reported.

[Karl, 2015/09/30 22:02:21]

Marking UserData and gen_crash_dag as unused. Surprisingly, when I mark  only
one as unused, I get the "unused parameter" error (doesn't matter which).

+  // Note: This code is (mostly) copied from llvm/lib/Support/ErrorHandling.cpp
+
+  // Blast the result out to stderr.  We don't try hard to make sure this
+  // succeeds (e.g. handling EINTR) and we can't use errs() here because
+  // raw ostreams can call report_fatal_error.
+  llvm::SmallVector<char, 64> Buffer;
+  llvm::raw_svector_ostream OS(Buffer);
+  OS << "LLVM ERROR: " << Reason << "\n";
+  llvm::StringRef MessageStr = OS.str();
+  ssize_t written = ::write(2, MessageStr.data(), MessageStr.size());
+  (void)written; // If something went wrong, we deliberately just give up.
+
+  // If we reached here, we are failing ungracefully. Run the interrupt handlers
+  // to make sure any special cleanups get done, in particular that we remove
+  // files registered with RemoveFileOnSignal.
+  llvm::sys::RunInterruptHandlers();
+
+  exit(0);
+}
+
 } // end of anonymous namespace
 
 void CLCompileServer::run() {
@@ -105,6 +129,10 @@ void CLCompileServer::run() {
   ClFlags::getParsedClFlags(Flags);
   ClFlags::getParsedClFlagsExtra(ExtraFlags);
 
+  // Override report_fatal_error if we want to exit with 0 status.
+  if (ExtraFlags.getAlwaysExitSuccess())
+    llvm::install_fatal_error_handler(reportFatalErrorThenExitSuccess, this);
+
   std::error_code EC;
   std::unique_ptr<Ostream> Ls = makeStream(ExtraFlags.getLogFilename(), EC);
   if (EC) {