From: Olivier Hainque <hain...@adacore.com>
Unlike the ARM port already there, aarch64 is dwarf CFI based
for unwinding and Android-Linux exposes kernel CFI for signal
handlers.
gcc/ada/ChangeLog:
* init.c (__gnat_error_handler): Map signals straight to Ada
exceptions, without a local CFI trampoline.
(__gnat_adjust_context_for_raise): Guard arm specific code on __arm__
compilation. Do nothing otherwise, relying on libgcc's signal
frame recognition for PC/RA adjustments.
Tested on x86_64-pc-linux-gnu, committed on master.
---
gcc/ada/init.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/gcc/ada/init.c b/gcc/ada/init.c
index 93e73f53c64..ad51e2e054d 100644
--- a/gcc/ada/init.c
+++ b/gcc/ada/init.c
@@ -2782,10 +2782,16 @@ __gnat_install_handler ()
void
__gnat_adjust_context_for_raise (int signo ATTRIBUTE_UNUSED, void *ucontext)
{
+#if defined(__arm__)
mcontext_t *mcontext = &((ucontext_t *) ucontext)->uc_mcontext;
/* ARM Bump has to be an even number because of odd/even architecture. */
((mcontext_t *) mcontext)->arm_pc += 2;
+#endif
+
+ /* Other ports, based on dwarf2 unwinding, typically leverage
+ kernel CFI coordinated with libgcc's explicit support for signal
+ frames. */
}
static void
@@ -2826,8 +2832,14 @@ __gnat_error_handler (int sig, siginfo_t *si, void
*ucontext)
{
__gnat_adjust_context_for_raise (sig, ucontext);
+ /* The ARM port relies on a sigtramp. Others such as aarch64,
+ dwarf info based, rely on kernel CFI. */
+#if defined(__arm__)
__gnat_sigtramp (sig, (void *) si, (void *) ucontext,
(__sigtramphandler_t *)&__gnat_map_signal);
+#else
+ __gnat_map_signal (sig, si, ucontext);
+#endif
}
/* This must be in keeping with System.OS_Interface.Alternate_Stack_Size. */
--
2.43.0
