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* [PATCH][RFC] location and BLOCK checker
@ 2013-01-10 15:38 Richard Biener
  2013-01-10 15:43 ` Jakub Jelinek
  0 siblings, 1 reply; 3+ messages in thread
From: Richard Biener @ 2013-01-10 15:38 UTC (permalink / raw)
  To: gcc-patches


The following is what I use to track down PR55792 - it adds verification
that the GIMPLE IL only contains references to BLOCKs that are part
of the functions BLOCK tree.  Otherwise BLOCKs lack a reference that is
seen by the garbage collector and funny things can happen.

It probably should also scan DEBUG_STMTs.

Do we want this in trunk or should it wait for stage1?

Thanks,
Richard.

Index: gcc/tree-cfg.c
===================================================================
*** gcc/tree-cfg.c.orig	2013-01-10 12:21:01.000000000 +0100
--- gcc/tree-cfg.c	2013-01-10 13:39:46.478923857 +0100
*************** verify_eh_throw_stmt_node (void **slot,
*** 4519,4524 ****
--- 4519,4581 ----
    return 1;
  }
  
+ /* Verify if the location LOCs block is in BLOCKS.  */
+ 
+ static bool
+ verify_location (pointer_set_t *blocks, location_t loc)
+ {
+   tree block = LOCATION_BLOCK (loc);
+   if (block != NULL_TREE
+       && !pointer_set_contains (blocks, block))
+     {
+       error ("location references block not in block tree");
+       return true;
+     }
+   return false;
+ }
+ 
+ /* Called via walk_tree.  Verify locations of expressions.  */
+ 
+ static tree
+ verify_expr_location_1 (tree *tp, int *walk_subtrees, void *data)
+ {
+   struct pointer_set_t *blocks = (struct pointer_set_t *) data;
+ 
+   if (!EXPR_P (*tp))
+     {
+       *walk_subtrees = false;
+       return NULL;
+     }
+ 
+   location_t loc = EXPR_LOCATION (*tp);
+   if (verify_location (blocks, loc))
+     return *tp;
+ 
+   return NULL;
+ }
+ 
+ /* Called via walk_gimple_op.  Verify locations of expressions.  */
+ 
+ static tree
+ verify_expr_location (tree *tp, int *walk_subtrees, void *data)
+ {
+   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+   return verify_expr_location_1 (tp, walk_subtrees, wi->info);
+ }
+ 
+ /* Insert all subblocks of BLOCK into BLOCKS and recurse.  */
+ 
+ static void
+ collect_subblocks (pointer_set_t *blocks, tree block)
+ {
+   tree t;
+   for (t = BLOCK_SUBBLOCKS (block); t; t = BLOCK_CHAIN (t))
+     {
+       pointer_set_insert (blocks, t);
+       collect_subblocks (blocks, t);
+     }
+ }
+ 
  /* Verify the GIMPLE statements in the CFG of FN.  */
  
  DEBUG_FUNCTION void
*************** verify_gimple_in_cfg (struct function *f
*** 4526,4537 ****
  {
    basic_block bb;
    bool err = false;
!   struct pointer_set_t *visited, *visited_stmts;
  
    timevar_push (TV_TREE_STMT_VERIFY);
    visited = pointer_set_create ();
    visited_stmts = pointer_set_create ();
  
    FOR_EACH_BB_FN (bb, fn)
      {
        gimple_stmt_iterator gsi;
--- 4583,4602 ----
  {
    basic_block bb;
    bool err = false;
!   struct pointer_set_t *visited, *visited_stmts, *blocks;
  
    timevar_push (TV_TREE_STMT_VERIFY);
    visited = pointer_set_create ();
    visited_stmts = pointer_set_create ();
  
+   /* Collect all BLOCKs referenced by the BLOCK tree of FN.  */
+   blocks = pointer_set_create ();
+   if (DECL_INITIAL (fn->decl))
+     {
+       pointer_set_insert (blocks, DECL_INITIAL (fn->decl));
+       collect_subblocks (blocks, DECL_INITIAL (fn->decl));
+     }
+ 
    FOR_EACH_BB_FN (bb, fn)
      {
        gimple_stmt_iterator gsi;
*************** verify_gimple_in_cfg (struct function *f
*** 4552,4557 ****
--- 4617,4629 ----
  
  	  err2 |= verify_gimple_phi (phi);
  
+ 	  /* Only PHI arguments have locations.  */
+ 	  if (gimple_location (phi) != UNKNOWN_LOCATION)
+ 	    {
+ 	      error ("PHI node with location");
+ 	      err2 = true;
+ 	    }
+ 
  	  for (i = 0; i < gimple_phi_num_args (phi); i++)
  	    {
  	      tree arg = gimple_phi_arg_def (phi, i);
*************** verify_gimple_in_cfg (struct function *f
*** 4562,4567 ****
--- 4634,4653 ----
  		  debug_generic_expr (addr);
  		  err2 |= true;
  		}
+ 	      location_t loc = gimple_phi_arg_location (phi, i);
+ 	      if (virtual_operand_p (gimple_phi_result (phi))
+ 		  && loc != UNKNOWN_LOCATION)
+ 		{
+ 		  error ("virtual PHI with argument locations");
+ 		  err2 = true;
+ 		}
+ 	      addr = walk_tree (&arg, verify_expr_location_1, blocks, NULL);
+ 	      if (addr)
+ 		{
+ 		  debug_generic_expr (addr);
+ 		  err2 = true;
+ 		}
+ 	      err2 |= verify_location (blocks, loc);
  	    }
  
  	  if (err2)
*************** verify_gimple_in_cfg (struct function *f
*** 4586,4591 ****
--- 4672,4678 ----
  	    }
  
  	  err2 |= verify_gimple_stmt (stmt);
+ 	  err2 |= verify_location (blocks, gimple_location (stmt));
  
  	  memset (&wi, 0, sizeof (wi));
  	  wi.info = (void *) visited;
*************** verify_gimple_in_cfg (struct function *f
*** 4597,4602 ****
--- 4684,4698 ----
  	      err2 |= true;
  	    }
  
+ 	  memset (&wi, 0, sizeof (wi));
+ 	  wi.info = (void *) blocks;
+ 	  addr = walk_gimple_op (stmt, verify_expr_location, &wi);
+ 	  if (addr)
+ 	    {
+ 	      debug_generic_expr (addr);
+ 	      err2 |= true;
+ 	    }
+ 
  	  /* ???  Instead of not checking these stmts at all the walker
  	     should know its context via wi.  */
  	  if (!is_gimple_debug (stmt)
*************** verify_gimple_in_cfg (struct function *f
*** 4651,4656 ****
--- 4747,4753 ----
  
    pointer_set_destroy (visited);
    pointer_set_destroy (visited_stmts);
+   pointer_set_destroy (blocks);
    verify_histograms ();
    timevar_pop (TV_TREE_STMT_VERIFY);
  }

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH][RFC] location and BLOCK checker
  2013-01-10 15:38 [PATCH][RFC] location and BLOCK checker Richard Biener
@ 2013-01-10 15:43 ` Jakub Jelinek
  2013-01-10 16:02   ` Richard Biener
  0 siblings, 1 reply; 3+ messages in thread
From: Jakub Jelinek @ 2013-01-10 15:43 UTC (permalink / raw)
  To: Richard Biener; +Cc: gcc-patches

On Thu, Jan 10, 2013 at 04:36:26PM +0100, Richard Biener wrote:
> 
> The following is what I use to track down PR55792 - it adds verification
> that the GIMPLE IL only contains references to BLOCKs that are part
> of the functions BLOCK tree.  Otherwise BLOCKs lack a reference that is
> seen by the garbage collector and funny things can happen.
> 
> It probably should also scan DEBUG_STMTs.
> 
> Do we want this in trunk or should it wait for stage1?

I'd say we want it in the trunk now (well, as soon as it doesn't report
regressions during bootstrap/regtest).  And yes, it should check also
DEBUG_STMTs, eventhough for now we completely ignore their locations.

	Jakub

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH][RFC] location and BLOCK checker
  2013-01-10 15:43 ` Jakub Jelinek
@ 2013-01-10 16:02   ` Richard Biener
  0 siblings, 0 replies; 3+ messages in thread
From: Richard Biener @ 2013-01-10 16:02 UTC (permalink / raw)
  To: Jakub Jelinek; +Cc: gcc-patches

On Thu, 10 Jan 2013, Jakub Jelinek wrote:

> On Thu, Jan 10, 2013 at 04:36:26PM +0100, Richard Biener wrote:
> > 
> > The following is what I use to track down PR55792 - it adds verification
> > that the GIMPLE IL only contains references to BLOCKs that are part
> > of the functions BLOCK tree.  Otherwise BLOCKs lack a reference that is
> > seen by the garbage collector and funny things can happen.
> > 
> > It probably should also scan DEBUG_STMTs.
> > 
> > Do we want this in trunk or should it wait for stage1?
> 
> I'd say we want it in the trunk now (well, as soon as it doesn't report
> regressions during bootstrap/regtest).  And yes, it should check also
> DEBUG_STMTs, eventhough for now we completely ignore their locations.

Ok, it seems it already does now.

Bootstrapped and tested on x86_64-unknown-linux-gnu with some
Fortran testsuite ICEs, LTO profiledbootstrap fails with verification
errors.  Checking regular LTO bootstrap now.

Richard.

2013-01-10  Richard Biener  <rguenther@suse.de>

	* tree-cfg.c (verify_node_sharing_1): Split out from ...
	(verify_node_sharing): ... here.
	(verify_expr_location, verify_expr_location_1, verify_location,
	collect_subblocks): New functions.
	(verify_gimple_in_cfg): Verify that locations only reference
	BLOCKs in the functions BLOCK tree.

Index: gcc/tree-cfg.c
===================================================================
*** gcc/tree-cfg.c.orig	2013-01-10 16:27:39.000000000 +0100
--- gcc/tree-cfg.c	2013-01-10 16:55:43.644221848 +0100
*************** tree_node_can_be_shared (tree t)
*** 4483,4495 ****
    return false;
  }
  
! /* Called via walk_gimple_stmt.  Verify tree sharing.  */
  
  static tree
! verify_node_sharing (tree *tp, int *walk_subtrees, void *data)
  {
!   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
!   struct pointer_set_t *visited = (struct pointer_set_t *) wi->info;
  
    if (tree_node_can_be_shared (*tp))
      {
--- 4483,4494 ----
    return false;
  }
  
! /* Called via walk_tree.  Verify tree sharing.  */
  
  static tree
! verify_node_sharing_1 (tree *tp, int *walk_subtrees, void *data)
  {
!   struct pointer_set_t *visited = (struct pointer_set_t *) data;
  
    if (tree_node_can_be_shared (*tp))
      {
*************** verify_node_sharing (tree *tp, int *walk
*** 4503,4508 ****
--- 4502,4516 ----
    return NULL;
  }
  
+ /* Called via walk_gimple_stmt.  Verify tree sharing.  */
+ 
+ static tree
+ verify_node_sharing (tree *tp, int *walk_subtrees, void *data)
+ {
+   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+   return verify_node_sharing_1 (tp, walk_subtrees, wi->info);
+ }
+ 
  static bool eh_error_found;
  static int
  verify_eh_throw_stmt_node (void **slot, void *data)
*************** verify_eh_throw_stmt_node (void **slot,
*** 4519,4524 ****
--- 4527,4589 ----
    return 1;
  }
  
+ /* Verify if the location LOCs block is in BLOCKS.  */
+ 
+ static bool
+ verify_location (pointer_set_t *blocks, location_t loc)
+ {
+   tree block = LOCATION_BLOCK (loc);
+   if (block != NULL_TREE
+       && !pointer_set_contains (blocks, block))
+     {
+       error ("location references block not in block tree");
+       return true;
+     }
+   return false;
+ }
+ 
+ /* Called via walk_tree.  Verify locations of expressions.  */
+ 
+ static tree
+ verify_expr_location_1 (tree *tp, int *walk_subtrees, void *data)
+ {
+   struct pointer_set_t *blocks = (struct pointer_set_t *) data;
+ 
+   if (!EXPR_P (*tp))
+     {
+       *walk_subtrees = false;
+       return NULL;
+     }
+ 
+   location_t loc = EXPR_LOCATION (*tp);
+   if (verify_location (blocks, loc))
+     return *tp;
+ 
+   return NULL;
+ }
+ 
+ /* Called via walk_gimple_op.  Verify locations of expressions.  */
+ 
+ static tree
+ verify_expr_location (tree *tp, int *walk_subtrees, void *data)
+ {
+   struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+   return verify_expr_location_1 (tp, walk_subtrees, wi->info);
+ }
+ 
+ /* Insert all subblocks of BLOCK into BLOCKS and recurse.  */
+ 
+ static void
+ collect_subblocks (pointer_set_t *blocks, tree block)
+ {
+   tree t;
+   for (t = BLOCK_SUBBLOCKS (block); t; t = BLOCK_CHAIN (t))
+     {
+       pointer_set_insert (blocks, t);
+       collect_subblocks (blocks, t);
+     }
+ }
+ 
  /* Verify the GIMPLE statements in the CFG of FN.  */
  
  DEBUG_FUNCTION void
*************** verify_gimple_in_cfg (struct function *f
*** 4526,4537 ****
  {
    basic_block bb;
    bool err = false;
!   struct pointer_set_t *visited, *visited_stmts;
  
    timevar_push (TV_TREE_STMT_VERIFY);
    visited = pointer_set_create ();
    visited_stmts = pointer_set_create ();
  
    FOR_EACH_BB_FN (bb, fn)
      {
        gimple_stmt_iterator gsi;
--- 4591,4610 ----
  {
    basic_block bb;
    bool err = false;
!   struct pointer_set_t *visited, *visited_stmts, *blocks;
  
    timevar_push (TV_TREE_STMT_VERIFY);
    visited = pointer_set_create ();
    visited_stmts = pointer_set_create ();
  
+   /* Collect all BLOCKs referenced by the BLOCK tree of FN.  */
+   blocks = pointer_set_create ();
+   if (DECL_INITIAL (fn->decl))
+     {
+       pointer_set_insert (blocks, DECL_INITIAL (fn->decl));
+       collect_subblocks (blocks, DECL_INITIAL (fn->decl));
+     }
+ 
    FOR_EACH_BB_FN (bb, fn)
      {
        gimple_stmt_iterator gsi;
*************** verify_gimple_in_cfg (struct function *f
*** 4552,4567 ****
  
  	  err2 |= verify_gimple_phi (phi);
  
  	  for (i = 0; i < gimple_phi_num_args (phi); i++)
  	    {
  	      tree arg = gimple_phi_arg_def (phi, i);
! 	      tree addr = walk_tree (&arg, verify_node_sharing, visited, NULL);
  	      if (addr)
  		{
  		  error ("incorrect sharing of tree nodes");
  		  debug_generic_expr (addr);
  		  err2 |= true;
  		}
  	    }
  
  	  if (err2)
--- 4625,4661 ----
  
  	  err2 |= verify_gimple_phi (phi);
  
+ 	  /* Only PHI arguments have locations.  */
+ 	  if (gimple_location (phi) != UNKNOWN_LOCATION)
+ 	    {
+ 	      error ("PHI node with location");
+ 	      err2 = true;
+ 	    }
+ 
  	  for (i = 0; i < gimple_phi_num_args (phi); i++)
  	    {
  	      tree arg = gimple_phi_arg_def (phi, i);
! 	      tree addr = walk_tree (&arg, verify_node_sharing_1, visited, NULL);
  	      if (addr)
  		{
  		  error ("incorrect sharing of tree nodes");
  		  debug_generic_expr (addr);
  		  err2 |= true;
  		}
+ 	      location_t loc = gimple_phi_arg_location (phi, i);
+ 	      if (virtual_operand_p (gimple_phi_result (phi))
+ 		  && loc != UNKNOWN_LOCATION)
+ 		{
+ 		  error ("virtual PHI with argument locations");
+ 		  err2 = true;
+ 		}
+ 	      addr = walk_tree (&arg, verify_expr_location_1, blocks, NULL);
+ 	      if (addr)
+ 		{
+ 		  debug_generic_expr (addr);
+ 		  err2 = true;
+ 		}
+ 	      err2 |= verify_location (blocks, loc);
  	    }
  
  	  if (err2)
*************** verify_gimple_in_cfg (struct function *f
*** 4586,4591 ****
--- 4680,4686 ----
  	    }
  
  	  err2 |= verify_gimple_stmt (stmt);
+ 	  err2 |= verify_location (blocks, gimple_location (stmt));
  
  	  memset (&wi, 0, sizeof (wi));
  	  wi.info = (void *) visited;
*************** verify_gimple_in_cfg (struct function *f
*** 4597,4602 ****
--- 4692,4706 ----
  	      err2 |= true;
  	    }
  
+ 	  memset (&wi, 0, sizeof (wi));
+ 	  wi.info = (void *) blocks;
+ 	  addr = walk_gimple_op (stmt, verify_expr_location, &wi);
+ 	  if (addr)
+ 	    {
+ 	      debug_generic_expr (addr);
+ 	      err2 |= true;
+ 	    }
+ 
  	  /* ???  Instead of not checking these stmts at all the walker
  	     should know its context via wi.  */
  	  if (!is_gimple_debug (stmt)
*************** verify_gimple_in_cfg (struct function *f
*** 4651,4656 ****
--- 4755,4761 ----
  
    pointer_set_destroy (visited);
    pointer_set_destroy (visited_stmts);
+   pointer_set_destroy (blocks);
    verify_histograms ();
    timevar_pop (TV_TREE_STMT_VERIFY);
  }

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2013-01-10 15:38 [PATCH][RFC] location and BLOCK checker Richard Biener
2013-01-10 15:43 ` Jakub Jelinek
2013-01-10 16:02   ` Richard Biener

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