[llvm-dev] [libunwind][Mips] Problem using gas to assemble UnwindRegistersSave.S

Vasileios Kalintiris via llvm-dev llvm-dev at lists.llvm.org
Thu Oct 1 02:07:35 PDT 2015

Hi Rich,

> Today just for fun I built clang/LLVM, libc++, libc++abi, libunwind,
> musl, binutils, and GDB for Mips using the integrated assembler

I've tried something similar but I used LLD, LLDB and the builtins library
from compiler-rt. Static builds were running fine but there are still
some small issues with shared linking which I'm trying to resolve.

I just want to clarify that libunwind isn't really supported on MIPS at the
moment. Here's the message from the commit (r248673) that enabled the building
of libunwind for MIPS:

   Currently, libunwind doesn't support MIPS. However, with this patch
   we do allow the library to build, and we warn the user about the lack of
   support for MIPS. Also, the dummy unw_getcontext() implementation for MIPS just
   traps on function entry in order to avoid any confusion with silent/weird
   failures at runtime.

   This allows us to test an LLVM-based toolchain without the dependency on a
   GCC toolchain. Of course, C++ exception handling and other things that depend
   on stack unwinding will not work until we add a proper implementation of the
   stub functions.

- Vasileios

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