[libcxxabi] r214573 - [unwinder] Tell the assembler that functions are functions so that the linker knows how to link them.

[Jonathan Roelofs]

On 8/2/14, 4:01 PM, Saleem Abdulrasool wrote:
> On Fri, Aug 1, 2014 at 3:02 PM, Jonathan Roelofs <jonathan at codesourcery.com
> <mailto:jonathan at codesourcery.com>> wrote:
>
>     Author: jroelofs
>     Date: Fri Aug  1 17:02:21 2014
>     New Revision: 214573
>
>     URL: http://llvm.org/viewvc/llvm-project?rev=214573&view=rev
>     Log:
>     [unwinder] Tell the assembler that functions are functions so that the
>     linker knows how to link them.
>
>     This fixes an interworking problem when the unwinder/libcxxabi is built for
>     Thumb. When unw_getcontext is not marked as a function, 'bl' is used for the
>     branch instead of 'bx'.
>
>     Modified:
>          libcxxabi/trunk/src/Unwind/assembly.h
>
>     Modified: libcxxabi/trunk/src/Unwind/assembly.h
>     URL:
>     http://llvm.org/viewvc/llvm-project/libcxxabi/trunk/src/Unwind/assembly.h?rev=214573&r1=214572&r2=214573&view=diff
>     ==============================================================================
>     --- libcxxabi/trunk/src/Unwind/assembly.h (original)
>     +++ libcxxabi/trunk/src/Unwind/assembly.h Fri Aug  1 17:02:21 2014
>     @@ -34,13 +34,32 @@
>       #define GLUE(a, b) GLUE2(a, b)
>       #define SYMBOL_NAME(name) GLUE(__USER_LABEL_PREFIX__, name)
>
>     +#if defined(__APPLE__)
>     +#define SYMBOL_IS_FUNC(name)
>     +#elif defined(__ELF__)
>     +#define LOCAL_LABEL(name) .L_##name
>
>
> Why is defined for ELF only?  Was this just an accidental copy?
Oops. Fixed in r214873.

Thanks!
Jon
>
>     +#if defined(__arm__)
>     +#define SYMBOL_IS_FUNC(name) .type name,%function
>     +#else
>     +#define SYMBOL_IS_FUNC(name) .type name, at function
>     +#endif
>     +#else
>     +#define SYMBOL_IS_FUNC(name)
>          \
>     +  .def name SEPARATOR
>         \
>     +    .scl 2 SEPARATOR
>          \
>     +    .type 32 SEPARATOR
>          \
>     +  .endef
>     +#endif
>     +
>       #define DEFINE_LIBUNWIND_FUNCTION(name)                   \
>         .globl SYMBOL_NAME(name) SEPARATOR                      \
>     +  SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR             \
>         SYMBOL_NAME(name):
>
>       #define DEFINE_LIBUNWIND_PRIVATE_FUNCTION(name)           \
>         .globl SYMBOL_NAME(name) SEPARATOR                      \
>         HIDDEN_DIRECTIVE SYMBOL_NAME(name) SEPARATOR            \
>     +  SYMBOL_IS_FUNC(SYMBOL_NAME(name)) SEPARATOR             \
>         SYMBOL_NAME(name):
>
>       #endif /* UNWIND_ASSEMBLY_H */
>
>
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>
>
>
> --
> Saleem Abdulrasool
> compnerd (at) compnerd (dot) org

-- 
Jon Roelofs
jonathan at codesourcery.com
CodeSourcery / Mentor Embedded