[DebugInfo][NFCI] Add unittest for DWARFAbbreviationDeclarationSet

The classes relevant to DWARFDebugAbbrev do not have any unittests
verifying their behavior. Seeing as there is not much error handling
around these classes right now, I want to add some testing as I plan on
making changes to these classes in the near future.

Differential Revision: https://reviews.llvm.org/D151001

Author: bulbazord

llvm/include/llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h

@@ -49,6 +49,8 @@ class DWARFAbbreviationDeclarationSet {
 
   std::string getCodeRange() const;
 
+  uint32_t getFirstAbbrCode() const { return FirstAbbrCode; }
+
 private:
   void clear();
 };

llvm/unittests/DebugInfo/DWARF/CMakeLists.txt

@@ -16,6 +16,7 @@ add_llvm_unittest(DebugInfoDWARFTests
   DwarfUtils.cpp
   DWARFAcceleratorTableTest.cpp
   DWARFDataExtractorTest.cpp
+  DWARFDebugAbbrevTest.cpp
   DWARFDebugArangeSetTest.cpp
   DWARFDebugFrameTest.cpp
   DWARFDebugInfoTest.cpp

llvm/unittests/DebugInfo/DWARF/DWARFDebugAbbrevTest.cpp

@@ -0,0 +1,105 @@
+//===- llvm/unittest/DebugInfo/DWARFDebugAbbrevTest.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/DebugInfo/DWARF/DWARFDebugAbbrev.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Testing/Support/Error.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+using namespace dwarf;
+
+enum Order : bool { InOrder, OutOfOrder };
+
+void WriteAbbreviationDeclarations(raw_ostream &OS, uint32_t FirstCode,
+                                   Order Ord) {
+  encodeULEB128(FirstCode, OS);
+  encodeULEB128(DW_TAG_compile_unit, OS);
+  OS << static_cast<uint8_t>(DW_CHILDREN_yes);
+  encodeULEB128(DW_AT_name, OS);
+  encodeULEB128(DW_FORM_strp, OS);
+  encodeULEB128(0, OS);
+  encodeULEB128(0, OS);
+
+  uint32_t SecondCode = Ord == Order::InOrder ? FirstCode + 1 : FirstCode - 1;
+
+  encodeULEB128(SecondCode, OS);
+  encodeULEB128(DW_TAG_subprogram, OS);
+  OS << static_cast<uint8_t>(DW_CHILDREN_no);
+  encodeULEB128(DW_AT_name, OS);
+  encodeULEB128(DW_FORM_strp, OS);
+  encodeULEB128(0, OS);
+  encodeULEB128(0, OS);
+}
+
+TEST(DWARFDebugAbbrevTest, DWARFAbbrevDeclSetExtractSuccess) {
+  SmallString<64> RawData;
+  raw_svector_ostream OS(RawData);
+  uint32_t FirstCode = 5;
+
+  WriteAbbreviationDeclarations(OS, FirstCode, InOrder);
+  encodeULEB128(0, OS);
+
+  uint64_t Offset = 0;
+  DataExtractor Data(RawData, sys::IsLittleEndianHost, sizeof(uint64_t));
+  DWARFAbbreviationDeclarationSet AbbrevSet;
+  const bool DataWasExtracted = AbbrevSet.extract(Data, &Offset);
+  EXPECT_TRUE(DataWasExtracted);
+  // The Abbreviation Declarations are in order and contiguous, so we want to
+  // make sure that FirstAbbrCode was correctly set
+  EXPECT_EQ(AbbrevSet.getFirstAbbrCode(), FirstCode);
+
+  const DWARFAbbreviationDeclaration *Abbrev5 =
+      AbbrevSet.getAbbreviationDeclaration(FirstCode);
+  EXPECT_TRUE(Abbrev5);
+  EXPECT_EQ(Abbrev5->getTag(), DW_TAG_compile_unit);
+  EXPECT_TRUE(Abbrev5->hasChildren());
+  EXPECT_EQ(Abbrev5->getNumAttributes(), 1u);
+
+  const DWARFAbbreviationDeclaration *Abbrev6 =
+      AbbrevSet.getAbbreviationDeclaration(FirstCode + 1);
+  EXPECT_TRUE(Abbrev6);
+  EXPECT_EQ(Abbrev6->getTag(), DW_TAG_subprogram);
+  EXPECT_FALSE(Abbrev6->hasChildren());
+  EXPECT_EQ(Abbrev6->getNumAttributes(), 1u);
+}
+
+TEST(DWARFDebugAbbrevTest, DWARFAbbrevDeclSetExtractSuccessOutOfOrder) {
+  SmallString<64> RawData;
+  raw_svector_ostream OS(RawData);
+  uint32_t FirstCode = 2;
+
+  WriteAbbreviationDeclarations(OS, FirstCode, OutOfOrder);
+  encodeULEB128(0, OS);
+
+  uint64_t Offset = 0;
+  DataExtractor Data(RawData, sys::IsLittleEndianHost, sizeof(uint64_t));
+  DWARFAbbreviationDeclarationSet AbbrevSet;
+  const bool DataWasExtracted = AbbrevSet.extract(Data, &Offset);
+  EXPECT_TRUE(DataWasExtracted);
+  // The declarations are out of order, ensure that FirstAbbrCode is UINT32_MAX
+  EXPECT_EQ(AbbrevSet.getFirstAbbrCode(), UINT32_MAX);
+
+  const DWARFAbbreviationDeclaration *Abbrev2 =
+      AbbrevSet.getAbbreviationDeclaration(FirstCode);
+  EXPECT_TRUE(Abbrev2);
+  EXPECT_EQ(Abbrev2->getTag(), DW_TAG_compile_unit);
+  EXPECT_TRUE(Abbrev2->hasChildren());
+  EXPECT_EQ(Abbrev2->getNumAttributes(), 1u);
+
+  const DWARFAbbreviationDeclaration *Abbrev1 =
+      AbbrevSet.getAbbreviationDeclaration(FirstCode - 1);
+  EXPECT_TRUE(Abbrev1);
+  EXPECT_EQ(Abbrev1->getTag(), DW_TAG_subprogram);
+  EXPECT_FALSE(Abbrev1->hasChildren());
+  EXPECT_EQ(Abbrev1->getNumAttributes(), 1u);
+}