[libunwind] Skip building unused parts when targeting SJLJ

[mstorsjo]

Summary

When SJLJ exceptions are used, those functions aren't used.

This fixes build failures on ARM with SJLJ enabled, such as armv7/iOS.

[compnerd]

src/libunwind.cpp

27

I would prefer that you used:

#if !defined(__USING_SJLJ_EXCEPTIONS__)

[mstorsjo]

Committed in SVN r314197.

src/UnwindLevel1.c

 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "libunwind.h"
 #include "unwind.h"
 #include "config.h"
 
-#if !defined(_LIBUNWIND_ARM_EHABI)
+#if !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__)
 
 static _Unwind_Reason_Code
 unwind_phase1(unw_context_t *uc, unw_cursor_t *cursor, _Unwind_Exception *exception_object) {
   unw_init_local(cursor, uc);
 
   // Walk each frame looking for a place to stop.
   bool handlerNotFound = true;
   while (handlerNotFound) {

 _LIBUNWIND_EXPORT void _Unwind_SetIP(struct _Unwind_Context *context,
                                      uintptr_t value) {
   _LIBUNWIND_TRACE_API("_Unwind_SetIP(context=%p, value=0x%0" PRIx64 ")",
                        (void *)context, (uint64_t)value);
   unw_cursor_t *cursor = (unw_cursor_t *)context;
   unw_set_reg(cursor, UNW_REG_IP, value);
 }
 
-#endif // !defined(_LIBUNWIND_ARM_EHABI)
+#endif // !defined(_LIBUNWIND_ARM_EHABI) && !defined(__USING_SJLJ_EXCEPTIONS__)

src/UnwindRegistersRestore.S

DEFINE_LIBUNWIND_PRIVATE_FUNCTION(_ZN9libunwind15Registers_arm646jumptoEv)
   ldp    d26,d27, [x0, #0x1E0]
   ldp    d28,d29, [x0, #0x1F0]
   ldr    d30,     [x0, #0x200]
   ldr    d31,     [x0, #0x208]
 
   ldp    x0, x1,  [x0, #0x000]  // restore x0,x1
   ret    x30                    // jump to pc
 
-#elif defined(__arm__) && !defined(__APPLE__)
+#elif defined(__arm__) && !(defined(__APPLE__) || defined(__USING_SJLJ_EXCEPTIONS__))
 
 #if !defined(__ARM_ARCH_ISA_ARM)
   .thumb
 #endif
 
 @
 @ void libunwind::Registers_arm::restoreCoreAndJumpTo()
 @

src/UnwindRegistersSave.S

DEFINE_LIBUNWIND_FUNCTION(unw_getcontext)
   stp    d24,d25, [x0, #0x1D0]
   stp    d26,d27, [x0, #0x1E0]
   stp    d28,d29, [x0, #0x1F0]
   str    d30,     [x0, #0x200]
   str    d31,     [x0, #0x208]
   mov    x0, #0                   // return UNW_ESUCCESS
   ret
 
-#elif defined(__arm__) && !defined(__APPLE__)
+#elif defined(__arm__) && !(defined(__APPLE__) || defined(__USING_SJLJ_EXCEPTIONS__))
 
 #if !defined(__ARM_ARCH_ISA_ARM)
   .thumb
 #endif
 
 @
 @ extern int unw_getcontext(unw_context_t* thread_state)
 @

src/libunwind.cpp

 #include <algorithm>
 
 #include "libunwind_ext.h"
 #include "config.h"
 
 #include <stdlib.h>
 
 
+#ifndef __USING_SJLJ_EXCEPTIONS__
 #include "AddressSpace.hpp"
 #include "UnwindCursor.hpp"
 
 using namespace libunwind;
 
 /// internal object to represent this processes address space
 LocalAddressSpace LocalAddressSpace::sThisAddressSpace;
 

 }
 
 /// IPI: for __deregister_frame()
 void _unw_remove_dynamic_fde(unw_word_t fde) {
   // fde is own mh_group
   DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
 }
 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
+#endif // !defined(__USING_SJLJ_EXCEPTIONS__)
 
 
 
 // Add logging hooks in Debug builds only
 #ifndef NDEBUG
 #include <stdlib.h>
 
 _LIBUNWIND_HIDDEN