On 8/9/19 4:39 PM, Martin Sebor wrote:
> On 8/9/19 6:41 AM, Martin Liška wrote:
>> Hi.
>>
>> The patch prevents crashes caused by fact that do_per_function_toporder
>> uses get_uid () to register all dead cgraph_nodes. That does not work
>> now as cgraph_nodes are directly released via ggc_free and so that one
>> will see a garbage here. Second steps is to register all cgraph hooks
>> and correctly hold add removed nodes. Doing that we'll not need the GGC nodes
>> array.
>>
>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>> I can also build xalancbmk with -O2 -ffast-math where I previously saw
>> the ICE.
>
> Just a comment on "style:" to make code more readable, GCC
> coding conventions call for variables to be defined at the same
> time as they're initialized (if possible). There's still lots
> of legacy C89 code that defines variables at the beginning of
> a function and initializes them much later, but in new C and
> C++ code we have the opportunity to follow it.
>
> Martin
Sure, I'm sending updated version of the patch.
Martin
>
> PS For some additional background see DCL19-C in the CERT C
> Coding Standard. A warning that helped find opportunities to
> reduce the scope of variables would be quite useful.
>
>>
>> Ready to be installed?
>> Thanks,
>> Martin
>>
>> gcc/ChangeLog:
>>
>> 2019-08-09 Martin Liska <mli...@suse.cz>
>>
>> PR ipa/91404
>> * passes.c (order): Remove.
>> (uid_hash_t): Likewise).
>> (remove_cgraph_node_from_order): Remove from set
>> of pointers (cgraph_node *).
>> (insert_cgraph_node_to_order): New.
>> (duplicate_cgraph_node_to_order): New.
>> (do_per_function_toporder): Register all 3 cgraph hooks.
>> Skip removed_nodes now as we know about all of them.
>> ---
>> gcc/passes.c | 69 +++++++++++++++++++++++++++++++++-------------------
>> 1 file changed, 44 insertions(+), 25 deletions(-)
>>
>>
>
>From 1700d3b86e3acd3d6603d9d804f5b0c8938af56e Mon Sep 17 00:00:00 2001
From: Martin Liska <mli...@suse.cz>
Date: Fri, 9 Aug 2019 13:50:31 +0200
Subject: [PATCH] Properly register dead cgraph_nodes in passes.c.
gcc/ChangeLog:
2019-08-09 Martin Liska <mli...@suse.cz>
PR ipa/91404
* passes.c (order): Remove.
(uid_hash_t): Likewise).
(remove_cgraph_node_from_order): Remove from set
of pointers (cgraph_node *).
(insert_cgraph_node_to_order): New.
(duplicate_cgraph_node_to_order): New.
(do_per_function_toporder): Register all 3 cgraph hooks.
Skip removed_nodes now as we know about all of them.
---
gcc/passes.c | 68 +++++++++++++++++++++++++++++++++-------------------
1 file changed, 43 insertions(+), 25 deletions(-)
diff --git a/gcc/passes.c b/gcc/passes.c
index bd56004d909..f715c67ab65 100644
--- a/gcc/passes.c
+++ b/gcc/passes.c
@@ -1646,24 +1646,39 @@ do_per_function (void (*callback) (function *, void *data), void *data)
}
}
-/* Because inlining might remove no-longer reachable nodes, we need to
- keep the array visible to garbage collector to avoid reading collected
- out nodes. */
-static int nnodes;
-static GTY ((length ("nnodes"))) cgraph_node **order;
-
-#define uid_hash_t hash_set<int_hash <int, 0, -1> >
-
/* Hook called when NODE is removed and therefore should be
excluded from order vector. DATA is a hash set with removed nodes. */
static void
remove_cgraph_node_from_order (cgraph_node *node, void *data)
{
- uid_hash_t *removed_nodes = (uid_hash_t *)data;
- removed_nodes->add (node->get_uid ());
+ hash_set<cgraph_node *> *removed_nodes = (hash_set<cgraph_node *> *)data;
+ removed_nodes->add (node);
+}
+
+/* Hook called when NODE is insert and therefore should be
+ excluded from removed_nodes. DATA is a hash set with removed nodes. */
+
+static void
+insert_cgraph_node_to_order (cgraph_node *node, void *data)
+{
+ hash_set<cgraph_node *> *removed_nodes = (hash_set<cgraph_node *> *)data;
+ removed_nodes->remove (node);
}
+/* Hook called when NODE is duplicated and therefore should be
+ excluded from removed_nodes. DATA is a hash set with removed nodes. */
+
+static void
+duplicate_cgraph_node_to_order (cgraph_node *node, cgraph_node *node2,
+ void *data)
+{
+ hash_set<cgraph_node *> *removed_nodes = (hash_set<cgraph_node *> *)data;
+ gcc_checking_assert (!removed_nodes->contains (node));
+ removed_nodes->remove (node2);
+}
+
+
/* If we are in IPA mode (i.e., current_function_decl is NULL), call
function CALLBACK for every function in the call graph. Otherwise,
call CALLBACK on the current function.
@@ -1677,26 +1692,30 @@ do_per_function_toporder (void (*callback) (function *, void *data), void *data)
callback (cfun, data);
else
{
- cgraph_node_hook_list *hook;
- uid_hash_t removed_nodes;
- gcc_assert (!order);
- order = ggc_vec_alloc<cgraph_node *> (symtab->cgraph_count);
+ hash_set<cgraph_node *> removed_nodes;
+ unsigned nnodes = symtab->cgraph_count;
+ cgraph_node **order = XNEWVEC (cgraph_node *, nnodes);
nnodes = ipa_reverse_postorder (order);
for (i = nnodes - 1; i >= 0; i--)
order[i]->process = 1;
- hook = symtab->add_cgraph_removal_hook (remove_cgraph_node_from_order,
- &removed_nodes);
+ cgraph_node_hook_list *removal_hook
+ = symtab->add_cgraph_removal_hook (remove_cgraph_node_from_order,
+ &removed_nodes);
+ cgraph_node_hook_list *insertion_hook
+ = symtab->add_cgraph_insertion_hook (insert_cgraph_node_to_order,
+ &removed_nodes);
+ cgraph_2node_hook_list *duplication_hook
+ = symtab->add_cgraph_duplication_hook (duplicate_cgraph_node_to_order,
+ &removed_nodes);
for (i = nnodes - 1; i >= 0; i--)
{
cgraph_node *node = order[i];
/* Function could be inlined and removed as unreachable. */
- if (node == NULL || removed_nodes.contains (node->get_uid ()))
+ if (node == NULL || removed_nodes.contains (node))
continue;
- /* Allow possibly removed nodes to be garbage collected. */
- order[i] = NULL;
node->process = 0;
if (node->has_gimple_body_p ())
{
@@ -1706,11 +1725,12 @@ do_per_function_toporder (void (*callback) (function *, void *data), void *data)
pop_cfun ();
}
}
- symtab->remove_cgraph_removal_hook (hook);
+ symtab->remove_cgraph_removal_hook (removal_hook);
+ symtab->remove_cgraph_insertion_hook (insertion_hook);
+ symtab->remove_cgraph_duplication_hook (duplication_hook);
+
+ free (order);
}
- ggc_free (order);
- order = NULL;
- nnodes = 0;
}
/* Helper function to perform function body dump. */
@@ -3046,5 +3066,3 @@ function_called_by_processed_nodes_p (void)
}
return e != NULL;
}
-
-#include "gt-passes.h"
--
2.22.0
