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); \
} \
