[Bug target/84113] [7/8 Regression] gcc-7.3.0/libgcc/unwind.inc:136:1: internal compiler error: in extract_insn, at recog.c:2311

[dougmencken at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84113

--- Comment #17 from Douglas Mencken <dougmencken at gmail dot com> ---
diff of libgcc/unwind-dw2.c between 6.4 and 7.1

--- a/libgcc/unwind-dw2.c
+++ b/libgcc/unwind-dw2.c
@@ -1,5 +1,5 @@
 /* DWARF2 exception handling and frame unwind runtime interface routines.
-   Copyright (C) 1997-2016 Free Software Foundation, Inc.
+   Copyright (C) 1997-2017 Free Software Foundation, Inc.

    This file is part of GCC.

@@ -136,6 +136,8 @@ struct _Unwind_Context
 #define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
   /* Context which has version/args_size/by_value fields.  */
 #define EXTENDED_CONTEXT_BIT ((~(_Unwind_Word) 0 >> 2) + 1)
+  /* Bit reserved on AArch64, return address has been signed with A key.  */
+#define RA_A_SIGNED_BIT ((~(_Unwind_Word) 0 >> 3) + 1)
   _Unwind_Word flags;
   /* 0 for now, can be increased when further fields are added to
      struct _Unwind_Context.  */
@@ -1185,6 +1187,11 @@ execute_cfa_program (const unsigned char *insn_ptr,
          break;

        case DW_CFA_GNU_window_save:
+#if defined (__aarch64__) && !defined (__ILP32__)
+         /* This CFA is multiplexed with Sparc.  On AArch64 it's used to
toggle
+            return address signing status.  */
+         fs->regs.reg[DWARF_REGNUM_AARCH64_RA_STATE].loc.offset ^= 1;
+#else
          /* ??? Hardcoded for SPARC register window configuration.  */
          if (__LIBGCC_DWARF_FRAME_REGISTERS__ >= 32)
            for (reg = 16; reg < 32; ++reg)
@@ -1192,6 +1199,7 @@ execute_cfa_program (const unsigned char *insn_ptr,
                fs->regs.reg[reg].how = REG_SAVED_OFFSET;
                fs->regs.reg[reg].loc.offset = (reg - 16) * sizeof (void *);
              }
+#endif
          break;

        case DW_CFA_GNU_args_size:
@@ -1513,10 +1521,15 @@ uw_update_context (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
        stack frame.  */
     context->ra = 0;
   else
-    /* Compute the return address now, since the return address column
-       can change from frame to frame.  */
-    context->ra = __builtin_extract_return_addr
-      (_Unwind_GetPtr (context, fs->retaddr_column));
+    {
+      /* Compute the return address now, since the return address column
+        can change from frame to frame.  */
+      context->ra = __builtin_extract_return_addr
+       (_Unwind_GetPtr (context, fs->retaddr_column));
+#ifdef MD_POST_EXTRACT_FRAME_ADDR
+      context->ra = MD_POST_EXTRACT_FRAME_ADDR (context, fs, context->ra);
+#endif
+    }
 }

 static void
@@ -1550,6 +1563,9 @@ uw_init_context_1 (struct _Unwind_Context *context,
                   void *outer_cfa, void *outer_ra)
 {
   void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
+#ifdef MD_POST_EXTRACT_ROOT_ADDR
+  ra = MD_POST_EXTRACT_ROOT_ADDR (ra);
+#endif
   _Unwind_FrameState fs;
   _Unwind_SpTmp sp_slot;
   _Unwind_Reason_Code code;
@@ -1586,6 +1602,9 @@ uw_init_context_1 (struct _Unwind_Context *context,
      initialization context, then we can't see it in the given
      call frame data.  So have the initialization context tell us.  */
   context->ra = __builtin_extract_return_addr (outer_ra);
+#ifdef MD_POST_EXTRACT_ROOT_ADDR
+  context->ra = MD_POST_EXTRACT_ROOT_ADDR (context->ra);
+#endif
 }

 static void _Unwind_DebugHook (void *, void *)
@@ -1608,6 +1627,21 @@ _Unwind_DebugHook (void *cfa __attribute__
((__unused__)),
 #endif
 }

+/* Frob exception handler's address kept in TARGET before installing into
+   CURRENT context.  */
+
+static inline void *
+uw_frob_return_addr (struct _Unwind_Context *current
+                    __attribute__ ((__unused__)),
+                    struct _Unwind_Context *target)
+{
+  void *ret_addr = __builtin_frob_return_addr (target->ra);
+#ifdef MD_POST_FROB_EH_HANDLER_ADDR
+  ret_addr = MD_POST_FROB_EH_HANDLER_ADDR (current, target, ret_addr);
+#endif
+  return ret_addr;
+}
+
 /* Install TARGET into CURRENT so that we can return to it.  This is a
    macro because __builtin_eh_return must be invoked in the context of
    our caller.  */
@@ -1616,7 +1650,7 @@ _Unwind_DebugHook (void *cfa __attribute__
((__unused__)),
   do                                                                   \
     {                                                                  \
       long offset = uw_install_context_1 ((CURRENT), (TARGET));               
\
-      void *handler = __builtin_frob_return_addr ((TARGET)->ra);       \
+      void *handler = uw_frob_return_addr ((CURRENT), (TARGET));       \
       _Unwind_DebugHook ((TARGET)->cfa, handler);                      \
       __builtin_eh_return (offset, handler);                           \
     }                                                                  \