Hi
As requested, attaching a patch for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96948. This solves a
problem with _Unwind_Backtrace() on mingw64 + SEH.
Best regards
Kirill
>From bbc163476cab9bcaaa044d8aa9ecee824f7284f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kirill=20M=C3=BCller?= <krl...@mailbox.org>
Date: Sun, 6 Sep 2020 10:01:46 +0200
Subject: [PATCH] Fix _Unwind_Backtrace() for SEH
---
libgcc/unwind-seh.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/libgcc/unwind-seh.c b/libgcc/unwind-seh.c
index 8c6aade9a3b3..a2d51b6df02b 100644
--- a/libgcc/unwind-seh.c
+++ b/libgcc/unwind-seh.c
@@ -450,8 +450,11 @@ _Unwind_Backtrace(_Unwind_Trace_Fn trace,
gcc_context.disp->ContextRecord = &ms_context;
gcc_context.disp->HistoryTable = &ms_history;
+ int first = 1;
while (1)
{
+ gcc_context.cfa = ms_context.Rsp;
+ gcc_context.ra = ms_context.Rip;
gcc_context.disp->ControlPc = ms_context.Rip;
gcc_context.disp->FunctionEntry
= RtlLookupFunctionEntry (ms_context.Rip, &gcc_context.disp->ImageBase,
@@ -466,9 +469,14 @@ _Unwind_Backtrace(_Unwind_Trace_Fn trace,
&gcc_context.disp->HandlerData,
&gcc_context.disp->EstablisherFrame, NULL);
- /* Call trace function. */
- if (trace (&gcc_context, trace_argument) != _URC_NO_REASON)
- return _URC_FATAL_PHASE1_ERROR;
+ /* Call trace function, skip first call. */
+ if (first) {
+ first = 0;
+ }
+ else {
+ if (trace (&gcc_context, trace_argument) != _URC_NO_REASON)
+ return _URC_FATAL_PHASE1_ERROR;
+ }
/* ??? Check for invalid stack pointer. */
if (ms_context.Rip == 0)
