[ObjectYAML][DWARF] Collect diagnostic message when YAMLParser fails.

[Higuoxing]

Summary

Before this patch, the diagnostic message is printed to errs() directly, which makes it difficult to use FailedWithMessage() in unit testing.
In this patch, we add a custom error handler for YAMLParser, which helps collect diagnostic messages and make it easy to use FailedWithMessage() to check error messages.

[jhenderson]

Thanks for this! I just want to make sure that the normal error message hasn't degraded as a result. Does yaml2obj produce the same full error message as before?

[Higuoxing]

In D82630#2116337, @jhenderson wrote:

Thanks for this! I just want to make sure that the normal error message hasn't degraded as a result. Does yaml2obj produce the same full error message as before?

DWARFYAML::emitDebugSections() isn't used in yaml2obj. It's only used in unit testing. Hence, this patch doesn't affect yaml2obj.

[jhenderson]

Great, LGTM, with one nit.

llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp

25

Since you don't do anything with the expected after this, this can just be EXPECT_THAT_EXPECTED - ASSERT_THAT_EXPECTED terminates the current test rather than allowing it to continue. This isn't relevant currently, but might be important should the test be extended to check the values that have been parsed. I don't think testing the values needs doing in this patch though, since this patch is about error handling.

[MaskRay]

Thanks!

llvm/lib/ObjectYAML/DWARFEmitter.cpp

480

*static_cast<SMDiagnostic *>(DiagContext) = Diag;

[Higuoxing]

Address comments.

Thanks for reviewing!

llvm/lib/ObjectYAML/DWARFEmitter.cpp

 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/ObjectYAML/DWARFYAML.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/SwapByteOrder.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
 #include <memory>
virtual void onValue(const MemoryBufferRef MBR) {
     Length += MBR.getBufferSize();
   }
 };
 } // namespace
 
 Expected<StringMap<std::unique_ptr<MemoryBuffer>>>
 DWARFYAML::emitDebugSections(StringRef YAMLString, bool ApplyFixups,
                              bool IsLittleEndian) {
-  yaml::Input YIn(YAMLString);
+  auto CollectDiagnostic = [](const SMDiagnostic &Diag, void *DiagContext) {
+    *static_cast<SMDiagnostic *>(DiagContext) = Diag;
+  };
+
+  SMDiagnostic GeneratedDiag;
+  yaml::Input YIn(YAMLString, /*Ctxt=*/nullptr, CollectDiagnostic,
+                  &GeneratedDiag);
 
   DWARFYAML::Data DI;
   DI.IsLittleEndian = IsLittleEndian;
   YIn >> DI;
   if (YIn.error())
-    return errorCodeToError(YIn.error());
+    return createStringError(YIn.error(), GeneratedDiag.getMessage());
 
   if (ApplyFixups) {
     DIEFixupVisitor DIFixer(DI);
     if (Error Err = DIFixer.traverseDebugInfo())
       return std::move(Err);
   }
 
   StringMap<std::unique_ptr<MemoryBuffer>> DebugSections;

llvm/unittests/ObjectYAML/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   Object
   ObjectYAML
   )
 
 add_llvm_unittest(ObjectYAMLTests
+  DWARFYAMLTest.cpp
   ELFYAMLTest.cpp
   MinidumpYAMLTest.cpp
   YAML2ObjTest.cpp
   YAMLTest.cpp
   )
 
 target_link_libraries(ObjectYAMLTests PRIVATE LLVMTestingSupport)

llvm/unittests/ObjectYAML/DWARFYAMLTest.cpp

+//===- DWARFYAMLTest.cpp - Tests for DWARFYAML.cpp ------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ObjectYAML/DWARFYAML.h"
+#include "llvm/ObjectYAML/DWARFEmitter.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+TEST(DebugAddrSection, TestParseDebugAddrYAML) {
+  StringRef Yaml = R"(
+debug_addr:
+  - Format:  DWARF64
+    Length:  0x1234
+    Version: 5
+)";
+  auto SectionsOrErr = DWARFYAML::emitDebugSections(Yaml);
+  EXPECT_THAT_EXPECTED(SectionsOrErr, Succeeded());
+}
+
+TEST(DebugAddrSection, TestMissingVersion) {
+  StringRef Yaml = R"(
+debug_addr:
+  - Format: DWARF64
+    Length: 0x1234
+)";
+  auto SectionsOrErr = DWARFYAML::emitDebugSections(Yaml);
+  EXPECT_THAT_ERROR(SectionsOrErr.takeError(),
+                    FailedWithMessage("missing required key 'Version'"));
+}
+
+TEST(DebugAddrSection, TestUnexpectedKey) {
+  StringRef Yaml = R"(
+debug_addr:
+  - Format:  DWARF64
+    Length:  0x1234
+    Version: 5
+    Blah:    unexpected
+)";
+  auto SectionsOrErr = DWARFYAML::emitDebugSections(Yaml);
+  EXPECT_THAT_ERROR(SectionsOrErr.takeError(),
+                    FailedWithMessage("unknown key 'Blah'"));
+}