From 4979ec08bb6db7b7b8b02ce371dd1471baae1a23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9ophile=20Bastian?= <contact@tobast.fr>
Date: Sat, 8 Jun 2019 15:38:11 +0200
Subject: [PATCH] unw_step: add unique id debugging features

---
 src/x86_64/Ginit_remote.c |  5 ++++-
 src/x86_64/Gstep.c        | 12 ++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/x86_64/Ginit_remote.c b/src/x86_64/Ginit_remote.c
index 93399143..8d8022f3 100644
--- a/src/x86_64/Ginit_remote.c
+++ b/src/x86_64/Ginit_remote.c
@@ -29,6 +29,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #include "../eh_elf/eh_elf.h"
 #include "unwind_i.h"
 
+int init_id = 0;
+
 PROTECTED int
 unw_init_remote (unw_cursor_t *cursor, unw_addr_space_t as, void *as_arg)
 {
@@ -42,7 +44,8 @@ unw_init_remote (unw_cursor_t *cursor, unw_addr_space_t as, void *as_arg)
   if (!tdep_init_done)
     tdep_init ();
 
-  Debug (1, "(cursor=%p)\n", c);
+  init_id++;
+  Debug (1, "(init_id=%d, cursor=%p)\n", init_id, c);
 
   switch(eh_elf_acc->init_mode) {
       case UNW_EH_ELF_INIT_PID:
diff --git a/src/x86_64/Gstep.c b/src/x86_64/Gstep.c
index 5ed2568e..e7b03072 100644
--- a/src/x86_64/Gstep.c
+++ b/src/x86_64/Gstep.c
@@ -55,6 +55,18 @@ is_plt_entry (struct dwarf_cursor *c)
   return ret;
 }
 
+extern int init_id;
+
+static int unw_step_id(unw_cursor_t *cursor) {
+    struct cursor *c = (struct cursor *) cursor;
+    return (
+            ((c->dwarf.ip + c->dwarf.cfa * 257) % 1000003)
+            + (1000003 * init_id))
+        % (1000000007);
+}
+
+#define UnwDebug(lvl, fmt, ...) Debug(lvl, "[%X] " fmt, unw_step_id(cursor), ##__VA_ARGS__)
+
 PROTECTED int
 unw_step (unw_cursor_t *cursor)
 {