From 1b864b5527535efbdc21224e39dbbac94e0e8cba Mon Sep 17 00:00:00 2001
From: Eric House <eehouse@trand>
Date: Mon, 28 Nov 2011 18:12:56 -0800
Subject: [PATCH] Add backtrace function.  May only work on Linux but still
 very useful.

---
 xwords4/linux/Makefile   |  2 +-
 xwords4/linux/linuxutl.c | 18 ++++++++++++++++++
 xwords4/linux/xptypes.h  |  3 +++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/xwords4/linux/Makefile b/xwords4/linux/Makefile
index 2f90dc32e..f5e870d2a 100644
--- a/xwords4/linux/Makefile
+++ b/xwords4/linux/Makefile
@@ -20,7 +20,7 @@ ifeq ($(MEMDEBUG),TRUE)
 DEFINES = -DMEM_DEBUG -DDEBUG -DENABLE_LOGGING -DNUMBER_KEY_AS_INDEX 
 DEFINES += -DCOMMS_CHECKSUM
 CFLAGS += -g $(GPROFFLAG) -Wall -Wunused-parameter -Wcast-align -Werror -O0
-CFLAGS += -DDEBUG_TS
+CFLAGS += -DDEBUG_TS -rdynamic 
 PLATFORM = obj_linux_memdbg
 else
 DEFINES =
diff --git a/xwords4/linux/linuxutl.c b/xwords4/linux/linuxutl.c
index 886231376..3593cd45c 100644
--- a/xwords4/linux/linuxutl.c
+++ b/xwords4/linux/linuxutl.c
@@ -25,6 +25,9 @@
 #include <string.h>
 #include <stdbool.h>
 #include <ctype.h>              /* BAD: use glib to support utf8 */
+#ifdef DEBUG
+# include <execinfo.h>          /* for backtrace */
+#endif
 
 #include "linuxutl.h"
 #include "main.h"
@@ -54,6 +57,21 @@ linux_debugf( const char* format, ... )
     
     fprintf( stderr, "%s\n", buf );
 }
+
+void
+linux_backtrace( void )
+{
+    void* buffer[128];
+    int nFound = backtrace( buffer, VSIZE(buffer) );
+    XP_ASSERT( nFound < VSIZE(buffer) );
+    char** traces = backtrace_symbols( buffer, nFound );
+    
+    XP_U16 ii;
+    for ( ii = 0; ii < nFound; ++ii ) {
+        XP_LOGF( "trace[%.2d]: %s", ii, traces[ii] );
+    }
+    free( traces );
+}
 #endif
 
 #ifndef MEM_DEBUG
diff --git a/xwords4/linux/xptypes.h b/xwords4/linux/xptypes.h
index 075120e11..5aa150573 100644
--- a/xwords4/linux/xptypes.h
+++ b/xwords4/linux/xptypes.h
@@ -115,8 +115,11 @@ void linux_lowerstr( XP_UCHAR* str );
 
 #ifdef DEBUG
 # define XP_ASSERT(b) assert(b)
+void linux_backtrace( void );
+# define XP_BACKTRACE linux_backtrace
 #else
 # define XP_ASSERT(b)
+# define XP_BACKTRACE
 #endif
 
 #define DGRAM_TYPE SOCK_DGRAM