[compiler-rt] [builtins] Provide a SEH specific __gcc_personality_seh0

[mstorsjo]

Summary

This matches how __gxx_personality_seh0 is hooked up in libcxxabi.

[rnk]

lgtm

[MaskRay]

compiler-rt/lib/builtins/gcc_personality_v0.c

254

Note the clang-format suggestion.

compiler-rt/lib/builtins/gcc_personality_v0.c

 // have a version of unwind.h which does not provide the EHABI declarations
 // which are quired for the C personality to conform to the specification.  In
 // order to provide forward compatibility for such compilers, we re-declare the
 // necessary interfaces in the helper to permit a standalone compilation of the
 // builtins (which contains the C unwinding personality for historical reasons).
 #include "unwind-ehabi-helpers.h"
 #endif
 
+#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+#include <windows.h>
+#include <winnt.h>
+
+EXCEPTION_DISPOSITION _GCC_specific_handler(PEXCEPTION_RECORD, void *, PCONTEXT,
+                                            PDISPATCHER_CONTEXT,
+                                            _Unwind_Personality_Fn);
+#endif
+
 // Pointer encodings documented at:
 //   http://refspecs.freestandards.org/LSB_1.3.0/gLSB/gLSB/ehframehdr.html
 
 #define DW_EH_PE_omit 0xff // no data follows
 
 #define DW_EH_PE_absptr 0x00
 #define DW_EH_PE_uleb128 0x01
 #define DW_EH_PE_udata2 0x02

 COMPILER_RT_ABI _Unwind_Reason_Code __gcc_personality_sj0(
     int version, _Unwind_Action actions, uint64_t exceptionClass,
     struct _Unwind_Exception *exceptionObject, struct _Unwind_Context *context)
 #elif USING_ARM_EHABI
 // The ARM EHABI personality routine has a different signature.
 COMPILER_RT_ABI _Unwind_Reason_Code __gcc_personality_v0(
     _Unwind_State state, struct _Unwind_Exception *exceptionObject,
     struct _Unwind_Context *context)
+#elif defined(__SEH__)
+static _Unwind_Reason_Code __gcc_personality_imp(
+    int version, _Unwind_Action actions, uint64_t exceptionClass,
+    struct _Unwind_Exception *exceptionObject, struct _Unwind_Context *context)
 #else
 COMPILER_RT_ABI _Unwind_Reason_Code __gcc_personality_v0(
     int version, _Unwind_Action actions, uint64_t exceptionClass,
     struct _Unwind_Exception *exceptionObject, struct _Unwind_Context *context)
 #endif
 {
   // Since C does not have catch clauses, there is nothing to do during
   // phase 1 (the search phase).
if ((start <= pcOffset) && (pcOffset < (start + length))) {
       _Unwind_SetIP(context, (funcStart + landingPad));
       return _URC_INSTALL_CONTEXT;
     }
   }
 
   // No landing pad found, continue unwinding.
   return continueUnwind(exceptionObject, context);
 }
+
+#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+COMPILER_RT_ABI EXCEPTION_DISPOSITION
+__gcc_personality_seh0(PEXCEPTION_RECORD ms_exc, void *this_frame,
+                       PCONTEXT ms_orig_context, PDISPATCHER_CONTEXT ms_disp) {
+  return _GCC_specific_handler(ms_exc, this_frame, ms_orig_context, ms_disp,
+                               __gcc_personality_imp);
+}
+#endif