dwarfdump: Add a bit more DWARF64 support

This test case was incorrect because it mixed DWARF32 and DWARF64 for a
single unit (DWARF32 unit referencing a DWARF64 str_offsets section). So
fix enough of the unit parsing for DWARF64 and make the test valid.

(not sure if anyone needs DWARF64 support though - support in
libDebugInfoDWARF has been added piecemeal and LLVM doesn't produce it
at all)

llvm-svn: 361582

llvm/include/llvm/DebugInfo/DWARF/DWARFUnit.h

@@ -48,7 +48,7 @@ class DWARFUnitHeader {
   uint32_t Offset = 0;
   // Version, address size, and DWARF format.
   dwarf::FormParams FormParams;
-  uint32_t Length = 0;
+  uint64_t Length = 0;
   uint64_t AbbrOffset = 0;
 
   // For DWO units only.
@@ -82,7 +82,7 @@ public:
   uint8_t getDwarfOffsetByteSize() const {
     return FormParams.getDwarfOffsetByteSize();
   }
-  uint32_t getLength() const { return Length; }
+  uint64_t getLength() const { return Length; }
   uint64_t getAbbrOffset() const { return AbbrOffset; }
   Optional<uint64_t> getDWOId() const { return DWOId; }
   void setDWOId(uint64_t Id) {
@@ -97,8 +97,11 @@ public:
     return UnitType == dwarf::DW_UT_type || UnitType == dwarf::DW_UT_split_type;
   }
   uint8_t getSize() const { return Size; }
-  // FIXME: Support DWARF64.
-  uint32_t getNextUnitOffset() const { return Offset + Length + 4; }
+  uint32_t getNextUnitOffset() const {
+    return Offset + Length +
+           (FormParams.Format == llvm::dwarf::DwarfFormat::DWARF64 ? 4 : 0) +
+           FormParams.getDwarfOffsetByteSize();
+  }
 };
 
 const DWARFUnitIndex &getDWARFUnitIndex(DWARFContext &Context,

llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp

@@ -242,16 +242,20 @@ bool DWARFUnitHeader::extract(DWARFContext &Context,
   if (!IndexEntry && Index)
     IndexEntry = Index->getFromOffset(*offset_ptr);
   Length = debug_info.getU32(offset_ptr);
-  // FIXME: Support DWARF64.
-  unsigned SizeOfLength = 4;
   FormParams.Format = DWARF32;
+  unsigned SizeOfLength = 4;
+  if (Length == 0xffffffff) {
+    Length = debug_info.getU64(offset_ptr);
+    FormParams.Format = DWARF64;
+    SizeOfLength = 8;
+  }
   FormParams.Version = debug_info.getU16(offset_ptr);
   if (FormParams.Version >= 5) {
     UnitType = debug_info.getU8(offset_ptr);
     FormParams.AddrSize = debug_info.getU8(offset_ptr);
-    AbbrOffset = debug_info.getU32(offset_ptr);
+    AbbrOffset = debug_info.getRelocatedValue(FormParams.getDwarfOffsetByteSize(), offset_ptr);
   } else {
-    AbbrOffset = debug_info.getRelocatedValue(4, offset_ptr);
+    AbbrOffset = debug_info.getRelocatedValue(FormParams.getDwarfOffsetByteSize(), offset_ptr);
     FormParams.AddrSize = debug_info.getU8(offset_ptr);
     // Fake a unit type based on the section type.  This isn't perfect,
     // but distinguishing compile and type units is generally enough.

llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp

@@ -100,7 +100,7 @@ bool DWARFVerifier::DieRangeInfo::intersects(const DieRangeInfo &RHS) const {
 bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
                                      uint32_t *Offset, unsigned UnitIndex,
                                      uint8_t &UnitType, bool &isUnitDWARF64) {
-  uint32_t AbbrOffset, Length;
+  uint64_t AbbrOffset, Length;
   uint8_t AddrSize = 0;
   uint16_t Version;
   bool Success = true;
@@ -114,22 +114,19 @@ bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
   uint32_t OffsetStart = *Offset;
   Length = DebugInfoData.getU32(Offset);
   if (Length == UINT32_MAX) {
+    Length = DebugInfoData.getU64(Offset);
     isUnitDWARF64 = true;
-    OS << format(
-        "Unit[%d] is in 64-bit DWARF format; cannot verify from this point.\n",
-        UnitIndex);
-    return false;
   }
   Version = DebugInfoData.getU16(Offset);
 
   if (Version >= 5) {
     UnitType = DebugInfoData.getU8(Offset);
     AddrSize = DebugInfoData.getU8(Offset);
-    AbbrOffset = DebugInfoData.getU32(Offset);
+    AbbrOffset = isUnitDWARF64 ? DebugInfoData.getU64(Offset) : DebugInfoData.getU32(Offset);
     ValidType = dwarf::isUnitType(UnitType);
   } else {
     UnitType = 0;
-    AbbrOffset = DebugInfoData.getU32(Offset);
+    AbbrOffset = isUnitDWARF64 ? DebugInfoData.getU64(Offset) : DebugInfoData.getU32(Offset);
     AddrSize = DebugInfoData.getU8(Offset);
   }
 
@@ -157,7 +154,7 @@ bool DWARFVerifier::verifyUnitHeader(const DWARFDataExtractor DebugInfoData,
     if (!ValidAddrSize)
       note() << "The address size is unsupported.\n";
   }
-  *Offset = OffsetStart + Length + 4;
+  *Offset = OffsetStart + Length + (isUnitDWARF64 ? 12 : 4);
   return Success;
 }
 

llvm/test/DebugInfo/X86/dwarfdump-str-offsets.s

@@ -239,18 +239,19 @@ TypeDie:
 CU1_5_end:
 
 # DWARF v5 CU header
-        .long  CU2_5_end-CU2_5_version  # Length of Unit
+        .long 0xffffffff
+        .quad CU2_5_end-CU2_5_version  # Length of Unit
 CU2_5_version:
         .short 5               # DWARF version number
         .byte 1                # DWARF Unit Type
         .byte 8                # Address Size (in bytes)
-        .long .debug_abbrev    # Offset Into Abbrev. Section
+        .quad .debug_abbrev    # Offset Into Abbrev. Section
 # The compile-unit DIE, which has a DW_AT_producer, DW_AT_name, 
 # DW_AT_str_offsets and DW_AT_compdir.
         .byte 1                # Abbreviation code
         .byte 0                # The index of the producer string
         .byte 1                # The index of the CU name string
-        .long .debug_str_offsets_base1
+        .quad .debug_str_offsets_base1
         .byte 2                # The index of the comp dir string
         .byte 0 # NULL
 CU2_5_end: