From 0a91f4830848ca16bf4b0569e45e23d7e8043368 Mon Sep 17 00:00:00 2001
From: Nico Rieck <nico.rieck@gmail.com>
Date: Wed, 26 Feb 2014 19:51:44 +0000
Subject: [PATCH] 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202292 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Object/COFFObjectFile.cpp                     |   8 ++++++--
 .../Inputs/zero-string-table.obj.coff-i386        | Bin 0 -> 704 bytes
 .../llvm-readobj/coff-zero-string-table.test      |   8 ++++++++
 3 files changed, 14 insertions(+), 2 deletions(-)
 create mode 100644 test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386
 create mode 100644 test/tools/llvm-readobj/coff-zero-string-table.test

diff --git a/lib/Object/COFFObjectFile.cpp b/lib/Object/COFFObjectFile.cpp
index 41d21eed139..0c79506f419 100644
--- a/lib/Object/COFFObjectFile.cpp
+++ b/lib/Object/COFFObjectFile.cpp
@@ -409,9 +409,13 @@ error_code COFFObjectFile::initSymbolTablePtr() {
       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;
 }
diff --git a/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386 b/test/tools/llvm-readobj/Inputs/zero-string-table.obj.coff-i386
new file mode 100644
index 0000000000000000000000000000000000000000..f41f224f60975e4e548c7afbb7e3ae759fdf376f
GIT binary patch
literal 704
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zKfr(CN%SUOJb3aZdQ@~KZ84?zl9!o%JF{eFXNx7^Y9?vTjQ}Je0^@a2Yc(@gcM0%?
zPN%=<Sp!llTm{O_==uKEK04P7-~~w_W8mA1E09Lek#D`2NWhPQ?<m?2WEu&TvZF*G
zTgnw29g;qgvq(x!u^IJr@TeW$cWxfOeRcN=@Q(T|G7Bs^VzumC2qkktsJxSAF09sk
z!Da1;yRy;9d5fhY<X|a1iKQnnt&1r%(<Xy$&s8#zjZm96vs%U8GuJGzVL1)%d7b_a
zL|c&ERkEq7$J)B*i$I%imx@{EFWL5jR@K+6uvPb@mM?JKu`ABX=8of@g;*D-Q-;7`
z95t-<a&U`9wPXK=^dvTKqZhmoOCoI&Ie{F*2mwAmG8XZlYq;|Glza7Q^BI1As6|FY
xR70-o)ZDHTpA@>41fy9QM0`rH(-=c@GI;&*38AY<Fq)A;WK2B*sZmU{{R??sYOMeO

literal 0
HcmV?d00001

diff --git a/test/tools/llvm-readobj/coff-zero-string-table.test b/test/tools/llvm-readobj/coff-zero-string-table.test
new file mode 100644
index 00000000000..dfcf79e2477
--- /dev/null
+++ b/test/tools/llvm-readobj/coff-zero-string-table.test
@@ -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
-- 
2.34.1