LTOModule::isBitcodeFile() shouldn't assert when returning false.

Fixes a bunch of assert-on-invalid-bitcode regressions after 315483.
Expected<> calls assertIsChecked() in its dtor, and operator bool() only calls
setChecked() if there's no error. So for functions that don't return an error
itself, the Expected<> version needs explicit code to disarm the error that the
ErrorOr<> code didn't need.

https://reviews.llvm.org/D39437


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317010 91177308-0d34-0410-b5e6-96231b3b80d8

lib/LTO/LTOModule.cpp

@@ -62,7 +62,11 @@ LTOModule::~LTOModule() {}
 bool LTOModule::isBitcodeFile(const void *Mem, size_t Length) {
   Expected<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer(
       MemoryBufferRef(StringRef((const char *)Mem, Length), "<mem>"));
-  return bool(BCData);
+  if (!BCData) {
+    consumeError(BCData.takeError());
+    return false;
+  }
+  return true;
 }
 
 bool LTOModule::isBitcodeFile(StringRef Path) {
@@ -73,7 +77,11 @@ bool LTOModule::isBitcodeFile(StringRef Path) {
 
   Expected<MemoryBufferRef> BCData = IRObjectFile::findBitcodeInMemBuffer(
       BufferOrErr.get()->getMemBufferRef());
-  return bool(BCData);
+  if (!BCData) {
+    consumeError(BCData.takeError());
+    return false;
+  }
+  return true;
 }
 
 bool LTOModule::isThinLTO() {
@@ -89,8 +97,10 @@ bool LTOModule::isBitcodeForTarget(MemoryBuffer *Buffer,
                                    StringRef TriplePrefix) {
   Expected<MemoryBufferRef> BCOrErr =
       IRObjectFile::findBitcodeInMemBuffer(Buffer->getMemBufferRef());
-  if (!BCOrErr)
+  if (!BCOrErr) {
+    consumeError(BCOrErr.takeError());
     return false;
+  }
   LLVMContext Context;
   ErrorOr<std::string> TripleOrErr =
       expectedToErrorOrAndEmitErrors(Context, getBitcodeTargetTriple(*BCOrErr));
@@ -102,8 +112,10 @@ bool LTOModule::isBitcodeForTarget(MemoryBuffer *Buffer,
 std::string LTOModule::getProducerString(MemoryBuffer *Buffer) {
   Expected<MemoryBufferRef> BCOrErr =
       IRObjectFile::findBitcodeInMemBuffer(Buffer->getMemBufferRef());
-  if (!BCOrErr)
+  if (!BCOrErr) {
+    consumeError(BCOrErr.takeError());
     return "";
+  }
   LLVMContext Context;
   ErrorOr<std::string> ProducerOrErr = expectedToErrorOrAndEmitErrors(
       Context, getBitcodeProducerString(*BCOrErr));

test/tools/lto/no-bitcode.s

@@ -0,0 +1,4 @@
+; libLTO.dylib shouldn't assert on invalid inputs.
+; RUN: llvm-mc -triple=arm64-apple-ios7.0.0 -filetype=obj -o %t.o
+; RUN: llvm-ar r %t.a %t.o
+; RUN: %ld64 -lto_library %llvmshlibdir/libLTO.dylib -arch x86_64 -dylib -mllvm -O0 -o %t.dylib %t.a