[DWARFv5] Support DW_FORM_line_strp in llvm-dwarfdump.

This form is like DW_FORM_strp, but points to .debug_line_str instead
of .debug_str as the string section.  It's intended to be used from
the line-table header, and allows string-pooling of directory and
filenames across compilation units.

Differential Revision: https://reviews.llvm.org/D42553

llvm-svn: 323476

4 files changed, 33 insertions, 13 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 76be5d7e6e7..aa55294ff4c 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -459,6 +459,16 @@ void DWARFContext::dump(
       strDWOOffset = offset;
     }
   }
+  if (shouldDump(Explicit, ".debug_line_str", DIDT_ID_DebugLineStr,
+                 DObj->getLineStringSection())) {
+    DataExtractor strData(DObj->getLineStringSection(), isLittleEndian(), 0);
+    uint32_t offset = 0;
+    uint32_t strOffset = 0;
+    while (const char *s = strData.getCStr(&offset)) {
+      OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
+      strOffset = offset;
+    }
+  }
 
   if (shouldDump(Explicit, ".debug_ranges", DIDT_ID_DebugRanges,
                  DObj->getRangeSection().Data)) {
@@ -1193,6 +1203,7 @@ class DWARFObjInMemory final : public DWARFObject {
   StringRef CUIndexSection;
   StringRef GdbIndexSection;
   StringRef TUIndexSection;
+  StringRef LineStringSection;
 
   SmallVector<SmallString<32>, 4> UncompressedSections;
 
@@ -1215,6 +1226,7 @@ class DWARFObjInMemory final : public DWARFObject {
         .Case("debug_cu_index", &CUIndexSection)
         .Case("debug_tu_index", &TUIndexSection)
         .Case("gdb_index", &GdbIndexSection)
+        .Case("debug_line_str", &LineStringSection)
         // Any more debug info sections go here.
         .Default(nullptr);
   }
@@ -1433,6 +1445,7 @@ public:
   const DWARFSection &getStringOffsetSection() const override {
     return StringOffsetSection;
   }
+  StringRef getLineStringSection() const override { return LineStringSection; }
 
   // Sections for DWARF5 split dwarf proposal.
   const DWARFSection &getInfoDWOSection() const override {
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp b/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
index 769ac37aa0b..d0fe05d1838 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
@@ -264,6 +264,7 @@ bool DWARFFormValue::isFormClass(DWARFFormValue::FormClass FC) const {
   case DW_FORM_strx2:
   case DW_FORM_strx3:
   case DW_FORM_strx4:
+  case DW_FORM_line_strp:
     return (FC == FC_String);
   case DW_FORM_implicit_const:
     return (FC == FC_Constant);
@@ -582,6 +583,11 @@ Optional<const char *> DWARFFormValue::getAsCString() const {
   if (Form == DW_FORM_GNU_strp_alt || U == nullptr)
     return None;
   uint32_t Offset = Value.uval;
+  if (Form == DW_FORM_line_strp) {
+    if (const char *Str = U->getLineStringExtractor().getCStr(&Offset))
+      return Str;
+    return None;
+  }
   if (Form == DW_FORM_GNU_str_index || Form == DW_FORM_strx ||
       Form == DW_FORM_strx1 || Form == DW_FORM_strx2 || Form == DW_FORM_strx3 ||
       Form == DW_FORM_strx4) {
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index df55d7debf9..7ed818b2ca3 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -34,8 +34,8 @@ void DWARFUnitSectionBase::parse(DWARFContext &C, const DWARFSection &Section) {
   const DWARFObject &D = C.getDWARFObj();
   parseImpl(C, Section, C.getDebugAbbrev(), &D.getRangeSection(),
             D.getStringSection(), D.getStringOffsetSection(),
-            &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(), false,
-            false);
+            &D.getAddrSection(), D.getLineSection(), D.getLineStringSection(),
+            D.isLittleEndian(), false, false);
 }
 
 void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
@@ -43,20 +43,21 @@ void DWARFUnitSectionBase::parseDWO(DWARFContext &C,
   const DWARFObject &D = C.getDWARFObj();
   parseImpl(C, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
             D.getStringDWOSection(), D.getStringOffsetDWOSection(),
-            &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
-            true, Lazy);
+            &D.getAddrSection(), D.getLineDWOSection(), StringRef(),
+            C.isLittleEndian(), true, Lazy);
 }
 
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
                      const DWARFDebugAbbrev *DA, const DWARFSection *RS,
                      StringRef SS, const DWARFSection &SOS,
-                     const DWARFSection *AOS, const DWARFSection &LS, bool LE,
-                     bool IsDWO, const DWARFUnitSectionBase &UnitSection,
+                     const DWARFSection *AOS, const DWARFSection &LS,
+                     StringRef LSS, bool LE, bool IsDWO,
+                     const DWARFUnitSectionBase &UnitSection,
                      const DWARFUnitIndex::Entry *IndexEntry)
     : Context(DC), InfoSection(Section), Abbrev(DA), RangeSection(RS),
-      LineSection(LS), StringSection(SS), StringOffsetSection(SOS),
-      AddrOffsetSection(AOS), isLittleEndian(LE), isDWO(IsDWO),
-      UnitSection(UnitSection), IndexEntry(IndexEntry) {
+      LineSection(LS), LineStringSection(LSS), StringSection(SS),
+      StringOffsetSection(SOS), AddrOffsetSection(AOS), isLittleEndian(LE),
+      isDWO(IsDWO), UnitSection(UnitSection), IndexEntry(IndexEntry) {
   clear();
 }
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index da3226ed0a2..c4723461a16 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -282,8 +282,8 @@ bool DWARFVerifier::handleDebugInfo() {
             DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
             &DObj.getRangeSection(), DObj.getStringSection(),
             DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
-            DObj.getLineSection(), DCtx.isLittleEndian(), false, TUSection,
-            nullptr));
+            DObj.getLineSection(), DObj.getLineStringSection(),
+            DCtx.isLittleEndian(), false, TUSection, nullptr));
         break;
       }
       case dwarf::DW_UT_skeleton:
@@ -297,8 +297,8 @@ bool DWARFVerifier::handleDebugInfo() {
             DCtx, DObj.getInfoSection(), DCtx.getDebugAbbrev(),
             &DObj.getRangeSection(), DObj.getStringSection(),
             DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
-            DObj.getLineSection(), DCtx.isLittleEndian(), false, CUSection,
-            nullptr));
+            DObj.getLineSection(), DObj.getLineStringSection(),
+            DCtx.isLittleEndian(), false, CUSection, nullptr));
         break;
       }
       default: { llvm_unreachable("Invalid UnitType."); }