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!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128799 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Object/ELFObjectFile.cpp

@@ -547,6 +547,7 @@ template<support::endianness target_endianness, bool is64Bits>
 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits>
                                           ::begin_sections() const {
   DataRefImpl ret;
+  memset(&ret, 0, sizeof(DataRefImpl));
   ret.p = reinterpret_cast<intptr_t>(base + Header->e_shoff);
   return section_iterator(SectionRef(ret, this));
 }
@@ -555,6 +556,7 @@ template<support::endianness target_endianness, bool is64Bits>
 ObjectFile::section_iterator ELFObjectFile<target_endianness, is64Bits>
                                           ::end_sections() const {
   DataRefImpl ret;
+  memset(&ret, 0, sizeof(DataRefImpl));
   ret.p = reinterpret_cast<intptr_t>(base
                                      + Header->e_shoff
                                      + (Header->e_shentsize * Header->e_shnum));