[PATCH] D64396: [DWARF] Dump .gdb_index of version 8

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: dblaikie, grimar, ikudrin.
Herald added subscribers: llvm-commits, arphaman, aprantl.
Herald added a project: LLVM.

gdb index version was bumped from 7 to 8 by commit 796a7ff8234cfaa8ad1ab884c1c8dafe29b18d42.
The format doesn't change.

Accept version 8 so that we can dump .gdb_index built by the 'save gdb-index' command of gdb (Jan 2013 or newer). Manually verified the result is plausible:

  mkdir dir; gdb a -batch -q -ex 'save gdb-index dir'; objcopy --add-section .gdb_index=dir/a.gdb-index --set-section-flags .gdb_index=readonly a b
  llvm-dwarfdump -gdb-index b


Repository:
  rL LLVM

https://reviews.llvm.org/D64396

Files:
  lib/DebugInfo/DWARF/DWARFGdbIndex.cpp
  test/DebugInfo/dwarfdump-dump-gdbindex.test


Index: test/DebugInfo/dwarfdump-dump-gdbindex.test
===================================================================
--- test/DebugInfo/dwarfdump-dump-gdbindex.test
+++ test/DebugInfo/dwarfdump-dump-gdbindex.test
@@ -1,4 +1,10 @@
-RUN: llvm-dwarfdump -gdb-index %p/Inputs/dwarfdump-gdbindex-v7.elf-x86-64 | FileCheck %s
+RUN: llvm-dwarfdump -gdb-index %p/Inputs/dwarfdump-gdbindex-v7.elf-x86-64 | \
+RUN:   FileCheck --check-prefixes=CHECK,CHECK-V7 %s
+
+; Change the version number (first byte of .gdb_index) from 7 to 8.
+RUN: cp %p/Inputs/dwarfdump-gdbindex-v7.elf-x86-64 %t
+RUN: %python -c 'with open("%/t", "r+b") as f: f.seek(0x1748); f.write(b"\x08")'
+RUN: llvm-dwarfdump -gdb-index %t | FileCheck --check-prefixes=CHECK,CHECK-V8 %s
 
 ; test.cpp:
 ; int main() { return 0; }
@@ -11,7 +17,8 @@
 ; Info about gdb-index: https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
 
 ; CHECK-LABEL: .gdb_index contents:
-; CHECK: Version = 7
+; CHECK-V7: Version = 7
+; CHECK-V8: Version = 8
 
 ; CHECK:      CU list offset = 0x18, has 2 entries:
 ; CHECK-NEXT:   0: Offset = 0x0, Length = 0x34
Index: lib/DebugInfo/DWARF/DWARFGdbIndex.cpp
===================================================================
--- lib/DebugInfo/DWARF/DWARFGdbIndex.cpp
+++ lib/DebugInfo/DWARF/DWARFGdbIndex.cpp
@@ -114,9 +114,9 @@
 bool DWARFGdbIndex::parseImpl(DataExtractor Data) {
   uint32_t Offset = 0;
 
-  // Only version 7 is supported at this moment.
+  // Only versions 7 and 8 are supported at this moment.
   Version = Data.getU32(&Offset);
-  if (Version != 7)
+  if (Version != 7 && Version != 8)
     return false;
 
   CuListOffset = Data.getU32(&Offset);


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