btrace: Replace struct btrace_function::segment.

This used to hold a pair of pointers to the previous and next function segment
that belong to this function call.  Replace with a pair of indices into the
vector of function segments.

5 files changed, 57 insertions, 37 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 45ea2b63fd..f09f1089ec 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,21 @@
 2017-05-30  Tim Wiederhake  <tim.wiederhake@intel.com>
 
+	* btrace.c (ftrace_fixup_caller, ftrace_new_return, ftrace_connect_bfun,
+	ftrace_bridge_gap): Replace references to btrace_thread_info::segment
+	with btrace_thread_info::next_segment and
+	btrace_thread_info::prev_segment.
+	* btrace.h: Remove struct btrace_func_link.
+	(struct btrace_function): Replace pair of function segment pointers
+	with pair of indices.
+	* python/py-record-btrace.c (btpy_call_prev_sibling,
+	btpy_call_next_sibling): Replace references to
+	btrace_thread_info::segment with btrace_thread_info::next_segment and
+	btrace_thread_info::prev_segment.
+	* record-btrace.c (record_btrace_frame_this_id): Use
+	btrace_find_call_by_number.
+
+2017-05-30  Tim Wiederhake  <tim.wiederhake@intel.com>
+
 	* btrace.c (ftrace_new_function, ftrace_fixup_level,
 	ftrace_connect_bfun, ftrace_bridge_gap, btrace_bridge_gaps,
 	btrace_insn_next, btrace_insn_prev): Remove references to
diff --git a/gdb/btrace.c b/gdb/btrace.c
index 43c5e8b271..f6ee7f10a4 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -271,20 +271,29 @@ ftrace_update_caller (struct btrace_function *bfun,
 /* Fix up the caller for all segments of a function.  */
 
 static void
-ftrace_fixup_caller (struct btrace_function *bfun,
+ftrace_fixup_caller (struct btrace_thread_info *btinfo,
+		     struct btrace_function *bfun,
 		     struct btrace_function *caller,
 		     enum btrace_function_flag flags)
 {
-  struct btrace_function *prev, *next;
+  unsigned int prev, next;
 
+  prev = bfun->prev;
+  next = bfun->next;
   ftrace_update_caller (bfun, caller, flags);
 
   /* Update all function segments belonging to the same function.  */
-  for (prev = bfun->segment.prev; prev != NULL; prev = prev->segment.prev)
-    ftrace_update_caller (prev, caller, flags);
+  for (; prev != 0; prev = bfun->prev)
+    {
+      bfun = ftrace_find_call_by_number (btinfo, prev);
+      ftrace_update_caller (bfun, caller, flags);
+    }
 
-  for (next = bfun->segment.next; next != NULL; next = next->segment.next)
-    ftrace_update_caller (next, caller, flags);
+  for (; next != 0; next = bfun->next)
+    {
+      bfun = ftrace_find_call_by_number (btinfo, next);
+      ftrace_update_caller (bfun, caller, flags);
+    }
 }
 
 /* Add a new function segment for a call at the end of the trace.
@@ -414,10 +423,10 @@ ftrace_new_return (struct btrace_thread_info *btinfo,
     {
       /* The caller of PREV is the preceding btrace function segment in this
 	 function instance.  */
-      gdb_assert (caller->segment.next == NULL);
+      gdb_assert (caller->next == 0);
 
-      caller->segment.next = bfun;
-      bfun->segment.prev = caller;
+      caller->next = bfun->number;
+      bfun->prev = caller->number;
 
       /* Maintain the function level.  */
       bfun->level = caller->level;
@@ -449,7 +458,7 @@ ftrace_new_return (struct btrace_thread_info *btinfo,
 	  bfun->level = prev->level - 1;
 
 	  /* Fix up the call stack for PREV.  */
-	  ftrace_fixup_caller (prev, bfun, BFUN_UP_LINKS_TO_RET);
+	  ftrace_fixup_caller (btinfo, prev, bfun, BFUN_UP_LINKS_TO_RET);
 
 	  ftrace_debug (bfun, "new return - no caller");
 	}
@@ -752,11 +761,11 @@ ftrace_connect_bfun (struct btrace_thread_info *btinfo,
   ftrace_debug (next, "..next");
 
   /* The function segments are not yet connected.  */
-  gdb_assert (prev->segment.next == NULL);
-  gdb_assert (next->segment.prev == NULL);
+  gdb_assert (prev->next == 0);
+  gdb_assert (next->prev == 0);
 
-  prev->segment.next = next;
-  next->segment.prev = prev;
+  prev->next = next->number;
+  next->prev = prev->number;
 
   /* We may have moved NEXT to a different function level.  */
   ftrace_fixup_level (btinfo, next, prev->level - next->level);
@@ -770,7 +779,7 @@ ftrace_connect_bfun (struct btrace_thread_info *btinfo,
       if (next != NULL)
 	{
 	  DEBUG_FTRACE ("using next's callers");
-	  ftrace_fixup_caller (prev, next, flags);
+	  ftrace_fixup_caller (btinfo, prev, next, flags);
 	}
     }
   else if (next->up == 0)
@@ -781,7 +790,7 @@ ftrace_connect_bfun (struct btrace_thread_info *btinfo,
       if (prev != NULL)
 	{
 	  DEBUG_FTRACE ("using prev's callers");
-	  ftrace_fixup_caller (next, prev, flags);
+	  ftrace_fixup_caller (btinfo, next, prev, flags);
 	}
     }
   else
@@ -809,7 +818,7 @@ ftrace_connect_bfun (struct btrace_thread_info *btinfo,
 	  DEBUG_FTRACE ("adding prev's tail calls to next");
 
 	  prev = ftrace_find_call_by_number (btinfo, prev->up);
-	  ftrace_fixup_caller (next, prev, prev_flags);
+	  ftrace_fixup_caller (btinfo, next, prev, prev_flags);
 
 	  for (; prev != NULL; prev = ftrace_find_call_by_number (btinfo,
 								  prev->up))
@@ -821,7 +830,7 @@ ftrace_connect_bfun (struct btrace_thread_info *btinfo,
 		  ftrace_debug (prev, "..top");
 		  ftrace_debug (caller, "..up");
 
-		  ftrace_fixup_caller (prev, caller, next_flags);
+		  ftrace_fixup_caller (btinfo, prev, caller, next_flags);
 
 		  /* If we skipped any tail calls, this may move CALLER to a
 		     different function level.
@@ -944,14 +953,13 @@ ftrace_bridge_gap (struct btrace_thread_info *btinfo,
 static void
 btrace_bridge_gaps (struct thread_info *tp, VEC (bfun_s) **gaps)
 {
-  struct btrace_thread_info *btinfo;
+  struct btrace_thread_info *btinfo = &tp->btrace;
   VEC (bfun_s) *remaining;
   struct cleanup *old_chain;
   int min_matches;
 
   DEBUG ("bridge gaps");
 
-  btinfo = &tp->btrace;
   remaining = NULL;
   old_chain = make_cleanup (VEC_cleanup (bfun_s), &remaining);
 
diff --git a/gdb/btrace.h b/gdb/btrace.h
index cd3f3467c9..ed5fe914b4 100644
--- a/gdb/btrace.h
+++ b/gdb/btrace.h
@@ -85,13 +85,6 @@ struct btrace_insn
 typedef struct btrace_insn btrace_insn_s;
 DEF_VEC_O (btrace_insn_s);
 
-/* A doubly-linked list of branch trace function segments.  */
-struct btrace_func_link
-{
-  struct btrace_function *prev;
-  struct btrace_function *next;
-};
-
 /* Flags for btrace function segments.  */
 enum btrace_function_flag
 {
@@ -146,10 +139,12 @@ struct btrace_function
   struct minimal_symbol *msym;
   struct symbol *sym;
 
-  /* The previous and next segment belonging to the same function.
-     If a function calls another function, the former will have at least
-     two segments: one before the call and another after the return.  */
-  struct btrace_func_link segment;
+  /* The function segment numbers of the previous and next segment belonging to
+     the same function.  If a function calls another function, the former will
+     have at least two segments: one before the call and another after the
+     return.  Will be zero if there is no such function segment.  */
+  unsigned int prev;
+  unsigned int next;
 
   /* The function segment number of the directly preceding function segment in
      a (fake) call stack.  Will be zero if there is no such function segment in
diff --git a/gdb/python/py-record-btrace.c b/gdb/python/py-record-btrace.c
index 9dd2199ad7..cd2be9fa97 100644
--- a/gdb/python/py-record-btrace.c
+++ b/gdb/python/py-record-btrace.c
@@ -416,11 +416,11 @@ recpy_bt_func_prev (PyObject *self, void *closure)
   if (func == NULL)
     return NULL;
 
-  if (func->segment.prev == NULL)
+  if (func->prev == 0)
     Py_RETURN_NONE;
 
   return recpy_func_new (((recpy_element_object *) self)->ptid,
-			 RECORD_METHOD_BTRACE, func->segment.prev->number);
+			 RECORD_METHOD_BTRACE, func->prev);
 }
 
 /* Implementation of RecordFunctionSegment.next [RecordFunctionSegment] for
@@ -434,11 +434,11 @@ recpy_bt_func_next (PyObject *self, void *closure)
   if (func == NULL)
     return NULL;
 
-  if (func->segment.next == NULL)
+  if (func->next == 0)
     Py_RETURN_NONE;
 
   return recpy_func_new (((recpy_element_object *) self)->ptid,
-			 RECORD_METHOD_BTRACE, func->segment.next->number);
+			 RECORD_METHOD_BTRACE, func->next);
 }
 
 /* Implementation of BtraceList.__len__ (self) -> int.  */
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 41f95b3596..55bc7a1a3a 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1584,6 +1584,7 @@ record_btrace_frame_this_id (struct frame_info *this_frame, void **this_cache,
 {
   const struct btrace_frame_cache *cache;
   const struct btrace_function *bfun;
+  struct btrace_call_iterator it;
   CORE_ADDR code, special;
 
   cache = (const struct btrace_frame_cache *) *this_cache;
@@ -1591,8 +1592,8 @@ record_btrace_frame_this_id (struct frame_info *this_frame, void **this_cache,
   bfun = cache->bfun;
   gdb_assert (bfun != NULL);
 
-  while (bfun->segment.prev != NULL)
-    bfun = bfun->segment.prev;
+  while (btrace_find_call_by_number (&it, &cache->tp->btrace, bfun->prev) != 0)
+    bfun = btrace_call_get (&it);
 
   code = get_frame_func (this_frame);
   special = bfun->number;