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);
}
