[PATCH] Put cleanups of cleanups after cleanups (PR gcov-profile/64634)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

Richard's GIMPLE EH rewrite in r151696 regressed following testcase.
The problem is that when lowering:
  [gcov-15.C:14:5] try
    {
      [gcov-15.C:18:12] D.2335 = __cxa_allocate_exception (4);
      [gcov-15.C:18:12] try
        {
          [gcov-15.C:18:12] [gcov-15.C:18:12] MEM[(int *)D.2335] = 5;
        }
      catch
        {
          [gcov-15.C:18:11] __cxa_free_exception (D.2335);
        }
      [gcov-15.C:18:11] __cxa_throw (D.2335, &_ZTIi, 0B);
    }
  catch
    {
      [gcov-15.C:20:3] catch (NULL)
        {
          [gcov-15.C:20:3] try
            {
              [gcov-15.C:20:10] D.2340 = __builtin_eh_pointer (0);
              [gcov-15.C:20:10] __cxa_begin_catch (D.2340);
              [gcov-15.C:22:15] catchEx ();
            }
          finally
            {
              [gcov-15.C:20:10] __cxa_end_catch ();
            }
        }
    }
we put the cleanup of the catch cleanup in front of the catch cleanup
in the EH sequence:
  [gcov-15.C:18:12] D.2335 = __cxa_allocate_exception (4);
  [gcov-15.C:18:12] [gcov-15.C:18:12] MEM[(int *)D.2335] = 5;
  [gcov-15.C:18:11] __cxa_throw (D.2335, &_ZTIi, 0B);
  <D.2345>:
  [gcov-15.C:24:1] D.2341 = 0;
  [gcov-15.C:24:1] goto <D.2342>;
  <D.2342>:
  [gcov-15.C:24:1] return D.2341;
  <D.2343>:
  [gcov-15.C:20:10] __cxa_end_catch ();
  resx 3
  <D.2346>:
  eh_dispatch 1
  resx 1
  <D.2344>:
  [gcov-15.C:20:10] D.2340 = __builtin_eh_pointer (1);
  [gcov-15.C:20:10] __cxa_begin_catch (D.2340);
  [gcov-15.C:22:15] catchEx ();
  [gcov-15.C:20:10] __cxa_end_catch ();
  goto <D.2345>;
and as the __cxa_end_catch () is the first bb for line 20,
gcov without -a considers that bb count as the one to be shown.
Before the gimple EH rewrite and also with this patch we instead
order the cleanup (__cxa_end_catch ()) after the __cxa_begin_catch ():
  [gcov-15.C:18:12] D.2335 = __cxa_allocate_exception (4);
  [gcov-15.C:18:12] [gcov-15.C:18:12] MEM[(int *)D.2335] = 5;
  [gcov-15.C:18:11] __cxa_throw (D.2335, &_ZTIi, 0B);
  <D.2345>:
  [gcov-15.C:24:1] D.2341 = 0;
  [gcov-15.C:24:1] goto <D.2342>;
  <D.2342>:
  [gcov-15.C:24:1] return D.2341;
  <D.2346>:
  eh_dispatch 1
  resx 1
  <D.2344>:
  [gcov-15.C:20:10] D.2340 = __builtin_eh_pointer (1);
  [gcov-15.C:20:10] __cxa_begin_catch (D.2340);
  [gcov-15.C:22:15] catchEx ();
  [gcov-15.C:20:10] __cxa_end_catch ();
  goto <D.2345>;
  <D.2343>:
  [gcov-15.C:20:10] __cxa_end_catch ();
  resx 3

Bootstrapped/regtested on x86_64-linux and i686-linux,
libstdc++.so.6 compiled without and with the patch is identical on
x86_64-linux.  The testcase also has identical generated code both at -O0
and -O2 when compiled without coverage.  Ok for trunk?

2015-02-18  Jakub Jelinek  <jakub@redhat.com>

	PR gcov-profile/64634
	* tree-eh.c (frob_into_branch_around): Fix up typos
	in function comment.
	(lower_catch): Put eh_seq resulting from EH lowering of
	the cleanup sequence after the cleanup rather than before
	it.

	* g++.dg/gcov/gcov-15.C: New test.

--- gcc/tree-eh.c.jj	2015-02-12 08:57:35.000000000 +0100
+++ gcc/tree-eh.c	2015-02-18 16:46:14.878887862 +0100
@@ -884,10 +884,10 @@ eh_region_may_contain_throw (eh_region r
 /* We want to transform
 	try { body; } catch { stuff; }
    to
-	normal_seqence:
+	normal_sequence:
 	  body;
 	  over:
-	eh_seqence:
+	eh_sequence:
 	  landing_pad:
 	  stuff;
 	  goto over;
@@ -1813,6 +1813,12 @@ lower_catch (struct leh_state *state, gt
   this_state.cur_region = state->cur_region;
   this_state.ehp_region = try_region;
 
+  /* Add eh_seq from lowering EH in the cleanup sequence after the cleanup
+     itself, so that e.g. for coverage purposes the nested cleanups don't
+     appear before the cleanup body.  See PR64634 for details.  */
+  gimple_seq old_eh_seq = eh_seq;
+  eh_seq = NULL;
+
   out_label = NULL;
   cleanup = gimple_try_cleanup (tp);
   for (gsi = gsi_start (cleanup);
@@ -1849,7 +1855,11 @@ lower_catch (struct leh_state *state, gt
 
   gimple_try_set_cleanup (tp, new_seq);
 
-  return frob_into_branch_around (tp, try_region, out_label);
+  gimple_seq new_eh_seq = eh_seq;
+  eh_seq = old_eh_seq;
+  gimple_seq ret_seq = frob_into_branch_around (tp, try_region, out_label);
+  gimple_seq_add_seq (&eh_seq, new_eh_seq);
+  return ret_seq;
 }
 
 /* A subroutine of lower_eh_constructs_1.  Lower a GIMPLE_TRY with a
--- gcc/testsuite/g++.dg/gcov/gcov-15.C.jj	2015-02-18 17:06:35.599727342 +0100
+++ gcc/testsuite/g++.dg/gcov/gcov-15.C	2015-02-18 17:17:04.483358209 +0100
@@ -0,0 +1,26 @@
+// PR gcov-profile/64634
+// { dg-options "-fprofile-arcs -ftest-coverage" }
+// { dg-do run { target native } }
+
+void catchEx ()		// count(1)
+{
+  __builtin_exit (0);	// count(1)
+  try
+  {}
+  catch (int)
+  {}
+}
+
+int main ()		// count(1)
+{
+  try
+  {
+    throw 5;		// count(1)
+  }
+  catch (...)		// count(1)
+  {
+    catchEx ();		// count(1)
+  }
+}
+
+// { dg-final { run-gcov gcov-15.C } }

	Jakub