Assorted bugfixes in object file handling:

 - Adds support for sniffing PE/COFF files on win32 (.exe and .dll)
   which are COFF files that have an MS-DOS compatibility stub on
   the front of them.

 - Fixes a bug in the COFFObjectFile's support for the Microsoft COFF
   extension for long symbol names, wherein it was attempting to parse
   the leading '/' in an extended symbol name reference as part of the
   integer offset.

 - Fixes bugs in COFFObjectFile and ELFObjectFile wherein section
   and symbol iterators were being returned with uninitialized bytes;
   the type DataRefImpl is a union between 2 32-bit words (d.a and d.b)
   and a single intptr_t word (p). Only p was being initialized, so in
   32-bit builds the result would be iterators with random upper 32-bit
   words in their DataRefImpls. This caused random failures when
   seeking around in object files.

Patch by Graydon Hoare!

llvm-svn: 128799

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Support/Path.cpp b/llvm/lib/Support/Path.cpp
index e5e875b..cfe23d8 100644
--- a/llvm/lib/Support/Path.cpp
+++ b/llvm/lib/Support/Path.cpp
@@ -15,11 +15,15 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Endian.h"
 #include <cassert>
 #include <cstring>
 #include <ostream>
 using namespace llvm;
 using namespace sys;
+namespace {
+using support::ulittle32_t;
+}
 
 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only TRULY operating system
@@ -129,6 +133,16 @@ sys::IdentifyFileType(const char *magic, unsigned length) {
       if (magic[1] == 0x02)
         return COFF_FileType;
       break;
+
+    case 0x4d: // Possible MS-DOS stub on Windows PE file
+      if (magic[1] == 0x5a) {
+        uint32_t off = *reinterpret_cast<const ulittle32_t *>(magic + 0x3c);
+        // PE/COFF file, either EXE or DLL.
+        if (off < length && memcmp(magic + off, "PE\0\0",4) == 0)
+          return COFF_FileType;
+      }
+      break;
+
     case 0x64: // x86-64 Windows.
       if (magic[1] == char(0x86))
         return COFF_FileType;