2 files changed, 101 insertions, 3 deletions

diff --git a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
index 0d299c9d840..1be0363adb0 100644
--- a/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DWARFDebugInfoTest.cpp
@@ -1007,6 +1007,99 @@ TEST(DWARFDebugInfo, TestDWARF32Version4Addr8Addresses) {
   TestAddresses<4, AddrType>();
 }
 
+TEST(DWARFDebugInfo, TestStringOffsets) {
+  Triple Triple = getHostTripleForAddrSize(sizeof(void *));
+  if (!isConfigurationSupported(Triple))
+    return;
+
+  const char *String1 = "Hello";
+  const char *String2 = "World";
+
+  auto ExpectedDG = dwarfgen::Generator::create(Triple, 5);
+  ASSERT_THAT_EXPECTED(ExpectedDG, Succeeded());
+  dwarfgen::Generator *DG = ExpectedDG.get().get();
+  dwarfgen::CompileUnit &CU = DG->addCompileUnit();
+  dwarfgen::DIE CUDie = CU.getUnitDIE();
+
+  CUDie.addStrOffsetsBaseAttribute();
+
+  uint16_t Attr = DW_AT_lo_user;
+
+  // Create our strings. First we create a non-indexed reference to String1,
+  // followed by an indexed String2. Finally, we add an indexed reference to
+  // String1.
+  const auto Attr1 = static_cast<dwarf::Attribute>(Attr++);
+  CUDie.addAttribute(Attr1, DW_FORM_strp, String1);
+
+  const auto Attr2 = static_cast<dwarf::Attribute>(Attr++);
+  CUDie.addAttribute(Attr2, DW_FORM_strx, String2);
+
+  const auto Attr3 = static_cast<dwarf::Attribute>(Attr++);
+  CUDie.addAttribute(Attr3, DW_FORM_strx, String1);
+
+  // Generate the DWARF
+  StringRef FileBytes = DG->generate();
+  MemoryBufferRef FileBuffer(FileBytes, "dwarf");
+  auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
+  ASSERT_TRUE((bool)Obj);
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(**Obj);
+  uint32_t NumCUs = DwarfContext->getNumCompileUnits();
+  ASSERT_EQ(NumCUs, 1u);
+  DWARFUnit *U = DwarfContext->getUnitAtIndex(0);
+  auto DieDG = U->getUnitDIE(false);
+  ASSERT_TRUE(DieDG.isValid());
+
+  // Now make sure the string offsets came out properly. Attr2 should have index
+  // 0 (because it was the first indexed string) even though the string itself
+  // was added eariler.
+  auto Extracted1 = toString(DieDG.find(Attr1));
+  ASSERT_TRUE((bool)Extracted1);
+  EXPECT_STREQ(String1, *Extracted1);
+
+  Optional<DWARFFormValue> Form2 = DieDG.find(Attr2);
+  ASSERT_TRUE((bool)Form2);
+  EXPECT_EQ(0u, Form2->getRawUValue());
+  auto Extracted2 = toString(Form2);
+  ASSERT_TRUE((bool)Extracted2);
+  EXPECT_STREQ(String2, *Extracted2);
+
+  Optional<DWARFFormValue> Form3 = DieDG.find(Attr3);
+  ASSERT_TRUE((bool)Form3);
+  EXPECT_EQ(1u, Form3->getRawUValue());
+  auto Extracted3 = toString(Form3);
+  ASSERT_TRUE((bool)Extracted3);
+  EXPECT_STREQ(String1, *Extracted3);
+}
+
+TEST(DWARFDebugInfo, TestEmptyStringOffsets) {
+  Triple Triple = getHostTripleForAddrSize(sizeof(void *));
+  if (!isConfigurationSupported(Triple))
+    return;
+
+  const char *String1 = "Hello";
+
+  auto ExpectedDG = dwarfgen::Generator::create(Triple, 5);
+  ASSERT_THAT_EXPECTED(ExpectedDG, Succeeded());
+  dwarfgen::Generator *DG = ExpectedDG.get().get();
+  dwarfgen::CompileUnit &CU = DG->addCompileUnit();
+  dwarfgen::DIE CUDie = CU.getUnitDIE();
+
+  uint16_t Attr = DW_AT_lo_user;
+
+  // We shall insert only one string. It will be referenced directly.
+  const auto Attr1 = static_cast<dwarf::Attribute>(Attr++);
+  CUDie.addAttribute(Attr1, DW_FORM_strp, String1);
+
+  // Generate the DWARF
+  StringRef FileBytes = DG->generate();
+  MemoryBufferRef FileBuffer(FileBytes, "dwarf");
+  auto Obj = object::ObjectFile::createObjectFile(FileBuffer);
+  ASSERT_TRUE((bool)Obj);
+  std::unique_ptr<DWARFContext> DwarfContext = DWARFContext::create(**Obj);
+  EXPECT_TRUE(
+      DwarfContext->getDWARFObj().getStringOffsetSection().Data.empty());
+}
+
 TEST(DWARFDebugInfo, TestRelations) {
   Triple Triple = getHostTripleForAddrSize(sizeof(void *));
   if (!isConfigurationSupported(Triple))
diff --git a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
index adc400c2fd0..973276616b8 100644
--- a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
@@ -71,15 +71,20 @@ void dwarfgen::DIE::addAttribute(uint16_t A, dwarf::Form Form,
     break;
 
   case DW_FORM_strp:
+    Die->addValue(
+        DG.getAllocator(), static_cast<dwarf::Attribute>(A), Form,
+        DIEString(DG.getStringPool().getEntry(*DG.getAsmPrinter(), String)));
+    break;
+
   case DW_FORM_GNU_str_index:
   case DW_FORM_strx:
   case DW_FORM_strx1:
   case DW_FORM_strx2:
   case DW_FORM_strx3:
   case DW_FORM_strx4:
-    Die->addValue(
-        DG.getAllocator(), static_cast<dwarf::Attribute>(A), Form,
-        DIEString(DG.getStringPool().getEntry(*DG.getAsmPrinter(), String)));
+    Die->addValue(DG.getAllocator(), static_cast<dwarf::Attribute>(A), Form,
+                  DIEString(DG.getStringPool().getIndexedEntry(
+                      *DG.getAsmPrinter(), String)));
     break;
 
   default: