[PATCH] Add .eh_frame_hdr search to Linux unwinder.

[Ed Schouten]

Just stumbled upon this patch and thought I'd chime in briefly.

I am currently working on a POSIX-like environment that is completely built around the concept of capability-based security which I am planning on releasing under a BSD license 1-2 months from now. I'm leaning on LLVM components quite heavily (LLVM, Clang, libcxx, libcxxabi, compiler-rt).

To get exceptions working in my environment I previously used a small patch to ld's linker script to add symbols where .eh_frame begins/ends and a change for libcxxabi to use those. After discovering this patch I decided to add dl_iterate_phdr() as well and revert my local changes. So far things work great. All libcxx exception related tests pass properly. At least on x86-64.

That said, keep in mind that ElfW() does not exist on FreeBSD. Adding some code like this makes the code build properly.

  #ifndef ElfW                                                                     
  #define ElfW(type) ElfW2(__INTPTR_WIDTH__, type)
  #define ElfW2(width, type) ElfW3(width, type)
  #define ElfW3(width, type) Elf##width##_##type
  #endif

Thanks!


http://reviews.llvm.org/D6848

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