gallium/util: libunwind support

It's kinda sad that (a) we don't have debug_backtrace support on !X86
and that (b) we re-invent our own crude backtrace support in the first
place.  If available, use libunwind instead.  The backtrace format is
based on what xserver and weston use, since it is nice not to have to
figure out a different format.

Signed-off-by: Rob Clark <[email protected]>
Acked-by: Nicolai Hähnle <[email protected]>

3 files changed, 105 insertions, 2 deletions

diff --git a/src/gallium/Automake.inc b/src/gallium/Automake.inc
index a01fa540531..48b5a440674 100644
--- a/src/gallium/Automake.inc
+++ b/src/gallium/Automake.inc
@@ -46,6 +46,7 @@ GALLIUM_TARGET_CFLAGS = \
 
 GALLIUM_COMMON_LIB_DEPS = \
 	-lm \
+	$(LIBUNWIND_LIBS) \
 	$(LIBSENSORS_LIBS) \
 	$(CLOCK_LIB) \
 	$(PTHREAD_LIBS) \
diff --git a/src/gallium/auxiliary/util/u_debug_stack.c b/src/gallium/auxiliary/util/u_debug_stack.c
index f941234de20..cf05f13ddd0 100644
--- a/src/gallium/auxiliary/util/u_debug_stack.c
+++ b/src/gallium/auxiliary/util/u_debug_stack.c
@@ -36,6 +36,95 @@
 #include "u_debug_symbol.h"
 #include "u_debug_stack.h"
 
+#if defined(HAVE_LIBUNWIND)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <dlfcn.h>
+
+void
+debug_backtrace_capture(struct debug_stack_frame *backtrace,
+                        unsigned start_frame,
+                        unsigned nr_frames)
+{
+   unw_cursor_t cursor;
+   unw_context_t context;
+   unw_proc_info_t pip;
+   unsigned i = 0;
+   int ret;
+
+   pip.unwind_info = NULL;
+
+   unw_getcontext(&context);
+   unw_init_local(&cursor, &context);
+
+   while ((start_frame > 0) && (unw_step(&cursor) > 0))
+      start_frame--;
+
+   while (unw_step(&cursor) > 0) {
+      char procname[256];
+      const char *filename;
+      unw_word_t off;
+      Dl_info dlinfo;
+
+      unw_get_proc_info(&cursor, &pip);
+
+      ret = unw_get_proc_name(&cursor, procname, 256, &off);
+      if (ret && ret != -UNW_ENOMEM) {
+         procname[0] = '?';
+         procname[1] = 0;
+      }
+
+       if (dladdr((void *)(uintptr_t)(pip.start_ip + off), &dlinfo) && dlinfo.dli_fname &&
+               *dlinfo.dli_fname)
+           filename = dlinfo.dli_fname;
+       else
+           filename = "?";
+
+      snprintf(backtrace[i].buf, sizeof(backtrace[i].buf),
+            "%u: %s (%s%s+0x%x) [%p]", i, filename, procname,
+            ret == -UNW_ENOMEM ? "..." : "", (int)off,
+            (void *)(uintptr_t)(pip.start_ip + off));
+
+      i++;
+   }
+
+   while (i < nr_frames) {
+      backtrace[i].buf[0] = '\0';
+      i++;
+   }
+}
+
+void
+debug_backtrace_dump(const struct debug_stack_frame *backtrace,
+                     unsigned nr_frames)
+{
+   unsigned i;
+
+   for (i = 0; i < nr_frames; ++i) {
+      if (backtrace[i].buf[0] == '\0')
+         break;
+      debug_printf("\t%s\n", backtrace[i].buf);
+   }
+}
+
+void
+debug_backtrace_print(FILE *f,
+                      const struct debug_stack_frame *backtrace,
+                      unsigned nr_frames)
+{
+   unsigned i;
+
+   for (i = 0; i < nr_frames; ++i) {
+      if (backtrace[i].buf[0] == '\0')
+         break;
+      fprintf(f, "\t%s\n", backtrace[i].buf);
+   }
+}
+
+#else /* ! HAVE_LIBUNWIND */
+
 #if defined(PIPE_OS_WINDOWS)
 #include <windows.h>
 #endif
@@ -179,3 +268,5 @@ debug_backtrace_print(FILE *f,
          fprintf(f, "%s\n", symbol);
    }
 }
+
+#endif /* HAVE_LIBUNWIND */
diff --git a/src/gallium/auxiliary/util/u_debug_stack.h b/src/gallium/auxiliary/util/u_debug_stack.h
index 04eba08f89a..0effcbe5259 100644
--- a/src/gallium/auxiliary/util/u_debug_stack.h
+++ b/src/gallium/auxiliary/util/u_debug_stack.h
@@ -30,6 +30,11 @@
 
 #include <stdio.h>
 
+#ifdef HAVE_LIBUNWIND
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#endif
+
 /**
  * @file
  * Stack backtracing.
@@ -46,15 +51,21 @@ extern "C" {
 /**
  * Represent a frame from a stack backtrace.
  *
- * XXX: Do not change this.
+#if defined(PIPE_OS_WINDOWS) && !defined(HAVE_LIBUNWIND)
+ * XXX: Do not change this. (passed to Windows' CaptureStackBackTrace())
+#endif
  *
  * TODO: This should be refactored as a void * typedef.
  */
 struct debug_stack_frame 
 {
+#ifdef HAVE_LIBUNWIND
+   char buf[128];
+#else
    const void *function;
+#endif
 };
-   
+
 
 void
 debug_backtrace_capture(struct debug_stack_frame *backtrace,