[llvm] r202292 - Relax COFF string table check

[Nico Rieck]

Author: nrieck
Date: Wed Feb 26 13:51:44 2014
New Revision: 202292

URL: http://llvm.org/viewvc/llvm-project?rev=202292&view=rev
Log:
Relax COFF string table check

COFF object files with 0 as string table size are currently rejected. This
prevents us from reading object files written by tools like cvtres that
violate the PECOFF spec and write 0 instead of 4 for the size of an empty
string table.

Added:
    llvm/trunk/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386
    llvm/trunk/test/tools/llvm-readobj/coff-zero-string-table.test
Modified:
    llvm/trunk/lib/Object/COFFObjectFile.cpp

Modified: llvm/trunk/lib/Object/COFFObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/COFFObjectFile.cpp?rev=202292&r1=202291&r2=202292&view=diff
==============================================================================
--- llvm/trunk/lib/Object/COFFObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/COFFObjectFile.cpp Wed Feb 26 13:51:44 2014
@@ -409,9 +409,13 @@ error_code COFFObjectFile::initSymbolTab
       getObject(StringTable, Data, StringTableAddr, StringTableSize))
     return EC;
 
+  // Treat table sizes < 4 as empty because contrary to the PECOFF spec, some
+  // tools like cvtres write a size of 0 for an empty table instead of 4.
+  if (StringTableSize < 4)
+      StringTableSize = 4;
+
   // Check that the string table is null terminated if has any in it.
-  if (StringTableSize < 4 ||
-      (StringTableSize > 4 && StringTable[StringTableSize - 1] != 0))
+  if (StringTableSize > 4 && StringTable[StringTableSize - 1] != 0)
     return  object_error::parse_failed;
   return object_error::success;
 }

Added: llvm/trunk/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386?rev=202292&view=auto
==============================================================================
Binary files llvm/trunk/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386 (added) and llvm/trunk/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386 Wed Feb 26 13:51:44 2014 differ

Added: llvm/trunk/test/tools/llvm-readobj/coff-zero-string-table.test
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-readobj/coff-zero-string-table.test?rev=202292&view=auto
==============================================================================
--- llvm/trunk/test/tools/llvm-readobj/coff-zero-string-table.test (added)
+++ llvm/trunk/test/tools/llvm-readobj/coff-zero-string-table.test Wed Feb 26 13:51:44 2014
@@ -0,0 +1,8 @@
+Ensure that we can read COFF objects with a string table size of 0 (instead
+of 4) for empty string tables.
+
+RUN: llvm-readobj -t %p/Inputs/zero-string-table.obj.coff-i386 | FileCheck %s
+
+CHECK: Symbols [
+CHECK:   Symbol {
+CHECK:     Name: $R000000