[llvm] r361589 - dwarfdump: Deterministically... determine whether parsing a DWARF32 or DWARF64 str_offsets header

[David Blaikie via llvm-commits]

Author: dblaikie
Date: Thu May 23 18:41:58 2019
New Revision: 361589

URL: http://llvm.org/viewvc/llvm-project?rev=361589&view=rev
Log:
dwarfdump: Deterministically... determine whether parsing a DWARF32 or DWARF64 str_offsets header

Rather than trying one and then the other - use the kind of the CU to
select which kind of header to parse.

Modified:
    llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
    llvm/trunk/test/DebugInfo/X86/dwarfdump-str-offsets-macho.s

Modified: llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp?rev=361589&r1=361588&r2=361589&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp (original)
+++ llvm/trunk/lib/DebugInfo/DWARF/DWARFUnit.cpp Thu May 23 18:41:58 2019
@@ -811,12 +811,19 @@ DWARFUnit::determineStringOffsetsTableCo
   auto Offset = toSectionOffset(getUnitDIE().find(DW_AT_str_offsets_base), 0);
   Optional<StrOffsetsContributionDescriptor> Descriptor;
   // Attempt to find a DWARF64 contribution 16 bytes before the base.
-  if (Offset >= 16)
+  switch (Header.getFormat()) {
+  case dwarf::DwarfFormat::DWARF64:
+    if (Offset < 16)
+      return None;
     Descriptor =
         parseDWARF64StringOffsetsTableHeader(DA, (uint32_t)Offset - 16);
-  // Try to find a DWARF32 contribution 8 bytes before the base.
-  if (!Descriptor && Offset >= 8)
+    break;
+  case dwarf::DwarfFormat::DWARF32:
+    if (Offset < 8)
+      return None;
     Descriptor = parseDWARF32StringOffsetsTableHeader(DA, (uint32_t)Offset - 8);
+    break;
+  }
   return Descriptor ? Descriptor->validateContributionSize(DA) : Descriptor;
 }
 

Modified: llvm/trunk/test/DebugInfo/X86/dwarfdump-str-offsets-macho.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dwarfdump-str-offsets-macho.s?rev=361589&r1=361588&r2=361589&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/dwarfdump-str-offsets-macho.s (original)
+++ llvm/trunk/test/DebugInfo/X86/dwarfdump-str-offsets-macho.s Thu May 23 18:41:58 2019
@@ -160,18 +160,19 @@ CU1_5_version:
 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 0                # Offset Into Abbrev. Section
+        .quad 0                # 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 Ldebug_str_offsets_base1-Ldebug_str_offsets
+        .quad Ldebug_str_offsets_base1-Ldebug_str_offsets
         .byte 2                # The index of the comp dir string
         .byte 0 # NULL
 CU2_5_end: