From 7c4609aa7a0569b76d4423cff2523703d8f178e6 Mon Sep 17 00:00:00 2001
From: Muthu Annamalai <muthu@panmo.cloud>
Date: Wed, 10 May 2023 17:54:36 +0000
Subject: [PATCH] [Backtrace] enable compile flag to trigger on at-exit; 6
 frame minimum shows clean atexit when there is not much of a stack Obtained 6
 stack frames. 1 | ./yosys(_Z17yosys_print_tracev+0x2e) [0x55c7a207830a] 2 |
 ./yosys(_Z12yosys_atexitv+0x9) [0x55c7a2078386] 3 | ./yosys(main+0x1c33)
 [0x55c7a207a020] 4 | /lib/x86_64-linux-gnu/libc.so.6(+0x23510)
 [0x7fae3a623510] 5 | /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x89)
 [0x7fae3a6235c9] 6 | ./yosys(_start+0x25) [0x55c7a2078215]

---
 Makefile         |  8 ++++++++
 kernel/driver.cc | 28 ++++++++++++++++++++++++++++
 kernel/log.h     |  1 +
 3 files changed, 37 insertions(+)

diff --git a/Makefile b/Makefile
index c622d3bd7..0f1630e37 100644
--- a/Makefile
+++ b/Makefile
@@ -24,6 +24,7 @@ DISABLE_VERIFIC_VHDL := 0
 ENABLE_COVER := 1
 ENABLE_LIBYOSYS := 0
 ENABLE_ZLIB := 1
+ENABLE_BACKTRACE := 0
 
 # python wrappers
 ENABLE_PYOSYS := 0
@@ -68,6 +69,8 @@ ifeq ($(ENABLE_PYOSYS),1)
 ENABLE_LIBYOSYS := 1
 endif
 
+
+
 BINDIR := $(PREFIX)/bin
 LIBDIR := $(PREFIX)/lib/$(PROGRAM_PREFIX)yosys
 DATDIR := $(PREFIX)/share/$(PROGRAM_PREFIX)yosys
@@ -125,6 +128,11 @@ PKG_CONFIG_PATH := $(BREW_PREFIX)/libffi/lib/pkgconfig:$(PKG_CONFIG_PATH)
 PKG_CONFIG_PATH := $(BREW_PREFIX)/tcl-tk/lib/pkgconfig:$(PKG_CONFIG_PATH)
 export PATH := $(BREW_PREFIX)/bison/bin:$(BREW_PREFIX)/gettext/bin:$(BREW_PREFIX)/flex/bin:$(PATH)
 
+ifeq ($(ENABLE_BACKTRACE),1)
+CXXFLAGS += -DYOSYS_BACKTRACE
+endif
+
+
 # macports search paths
 else ifneq ($(shell :; command -v port),)
 PORT_PREFIX := $(patsubst %/bin/port,%,$(shell :; command -v port))
diff --git a/kernel/driver.cc b/kernel/driver.cc
index ef8e77924..c9e48177d 100644
--- a/kernel/driver.cc
+++ b/kernel/driver.cc
@@ -83,6 +83,32 @@ int getopt(int argc, char **argv, const char *optstring)
 }
 #endif
 
+#if !defined(_WIN32) || defined(__MINGW32__) || defined(YOSYS_BACKTRACE)
+#include <execinfo.h>
+void yosys_print_trace (void)
+{
+  void *array[32] = {0,};
+  char **strings;
+
+  int size = backtrace (array, 32);
+  strings = backtrace_symbols (array, size);
+  if (strings != NULL && size > 6)
+  {
+
+    fprintf (stderr,"Obtained %d stack frames.\n", size);
+    for (int i = 0; i < size; i++)
+      fprintf(stderr,"%d | %s\n", i+1, strings[i]);
+    free (strings);
+  }
+
+}
+#else
+void yosys_print_trace()
+{
+  fprintf(stderr,"Backtrace not available on this platform,\n");
+}
+#endif
+
 
 USING_YOSYS_NAMESPACE
 
@@ -174,6 +200,8 @@ extern "C" {
 
 void yosys_atexit()
 {
+  
+  yosys_print_trace();
 #if defined(YOSYS_ENABLE_READLINE) || defined(YOSYS_ENABLE_EDITLINE)
 	if (!yosys_history_file.empty()) {
 #if defined(YOSYS_ENABLE_READLINE)
diff --git a/kernel/log.h b/kernel/log.h
index dfcbc1137..26053a540 100644
--- a/kernel/log.h
+++ b/kernel/log.h
@@ -43,6 +43,7 @@
 #  endif
 #endif
 
+
 #if defined(_MSC_VER)
 // At least this is not in MSVC++ 2013.
 #  define __PRETTY_FUNCTION__ __FUNCTION__