[unittest][DebugInfo/DWARF] Check that dwarfgen::Generator is created

[ikudrin]

Summary

If Generator::create() returns an error, tests should fail gracefully and report the cause, for example:

[ RUN      ] DebugLineBasicFixture.ParserSkipsCorrectly
.../llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp:47: Failure
Value of: llvm::detail::TakeExpected(ExpectedGenerator)
Expected: succeeded
  Actual: failed  (no asm backend for target nvptx64-nvidia-cuda)

[dblaikie]

Sounds good!

llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp

48

Side note, as a separate change perhaps (though don't mind if it's in this one really) this should be:

Gen = std::move(*ExpectedGenerator);

[MaskRay]

Thanks!

[ikudrin]

llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp

48

Sure, thanks!

llvm/unittests/DebugInfo/DWARF/DWARFDebugLineTest.cpp

CommonFixture()
         RecordUnrecoverable(std::bind(&CommonFixture::recordUnrecoverable, this,
                                       std::placeholders::_1)){};
 
   ~CommonFixture() {
     EXPECT_FALSE(Recoverable);
     EXPECT_FALSE(Unrecoverable);
   }
 
-  bool setupGenerator(uint16_t Version = 4, uint8_t AddrSize = 8) {
+  // Note: ASSERT_THAT_EXPECTED cannot be used in a non-void function, so
+  // setupGenerator() is split into two.
+  void setupGeneratorImpl(uint16_t Version, uint8_t AddrSize) {
     AddressSize = AddrSize;
-    Triple T =
-        getDefaultTargetTripleForAddrSize(AddressSize == 0 ? 8 : AddressSize);
+    Triple T = getDefaultTargetTripleForAddrSize(AddressSize ? AddressSize : 8);
     if (!isConfigurationSupported(T))
-      return false;
+      return;
     auto ExpectedGenerator = Generator::create(T, Version);
-    if (ExpectedGenerator)
-      Gen.reset(ExpectedGenerator->release());
-    return true;
+    ASSERT_THAT_EXPECTED(ExpectedGenerator, Succeeded());
+    Gen = std::move(*ExpectedGenerator);
+  }
+
+  bool setupGenerator(uint16_t Version = 4, uint8_t AddrSize = 8) {
+    setupGeneratorImpl(Version, AddrSize);
+    return Gen != nullptr;
   }
 
   void generate() {
     Context = createContext();
     assert(Context != nullptr && "test state is not valid");
     const DWARFObject &Obj = Context->getDWARFObj();
     uint8_t TargetAddrSize = AddressSize == 0 ? 8 : AddressSize;
     LineData = DWARFDataExtractor(
         Obj, Obj.getLineSection(),
         getDefaultTargetTripleForAddrSize(TargetAddrSize).isLittleEndian(),
         AddressSize);
   }
 
   std::unique_ptr<DWARFContext> createContext() {
-    if (!Gen)
-      return nullptr;
+    assert(Gen != nullptr && "Generator is not set up");
     StringRef FileBytes = Gen->generate();
     MemoryBufferRef FileBuffer(FileBytes, "dwarf");
     auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
     if (Obj)
       return DWARFContext::create(**Obj);
     return nullptr;
   }