asl added inline comments.
================
Comment at: include/unwind.h:224
@@ +223,3 @@
+
+static __inline__ uintptr_t _Unwind_GetGR(struct _Unwind_Context *context,
+ int index) {
----------------
logan wrote:
> asl wrote:
> > Why can't we simply make them static functions of UnwindLevel1.c for EHABI
> > case?
> They can't be //static// functions of UnwindLevel1.c because they will be
> called from the other source code (e.g. libc++abi calls these functions.) If
> they are declared as static functions in UnwindLevel1.c, then the other
> source code can't access these functions.
>
> We can't declare these functions as extern and define these functions in
> UnwindLevel1.c either. If we do so, the source code including this header
> and using these functions will be compiled to object files with external
> symbols (undefined references) to these functions. This means that these
> symbols should be available to the linkers. However, libgcc does not provide
> these symbols. If we are building libc++abi with libgcc without libunwinder,
> then we will encounter the following link error:
>
> libcxxabi/src/cxa_personality.cpp:(.text+0x3c): undefined reference to
> `_Unwind_SetGR'
> (... and etc ...)
>
> This is the reason why these functions must be inlined. AFAICT, both the
> unwind.h from gcc or clang (`lib/Header/unwind.h`) are following the same
> practice.
I see. My biggest concern is the use of LIBCXXABI_ARM_EHABI define. We need to
resolve this beforehand, because currently we're having a cyclic dependency
between libunwind and libcxxabi via __cxxabi_config.h. I'd simply fold it
inside libwunwind (or introduce __libunwind_config.h)
http://reviews.llvm.org/D11190
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