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Re: [PATCH] Fix part of PR58712


On 2013.10.15 at 12:49 +0200, Richard Biener wrote:
> On Tue, Oct 15, 2013 at 12:31 PM, Markus Trippelsdorf
> <markus@trippelsdorf.de> wrote:
> > Valgrind complains:
> > ==27870== Conditional jump or move depends on uninitialised value(s)
> > ==27870==    at 0x557CDC: cgraph_create_edge_1(cgraph_node*, cgraph_node*, gimple_statement_d*, long, int) (cgraph.c:695)
> > ==27870==    by 0x55882E: cgraph_create_edge(cgraph_node*, cgraph_node*, gimple_statement_d*, long, int) (cgraph.c:890)
> > ==27870==    by 0x560891: cgraph_clone_edge(cgraph_edge*, cgraph_node*, gimple_statement_d*, unsigned int, long, int, bool) (cgraphclones.c:135)
> > ==27870==    by 0x7F1F14: copy_body(copy_body_data*, long, int, basic_block_def*, basic_block_def*, basic_block_def*) (tree-inline.c:1741)
> > ...
> > ==27870==  Uninitialised value was created by a client request
> > ==27870==    at 0x50BBEE: ggc_internal_alloc_stat(unsigned long) (ggc-page.c:1339)
> > ==27870==    by 0x557D92: cgraph_create_edge_1(cgraph_node*, cgraph_node*, gimple_statement_d*, long, int) (cgraph.c:842)
> > ==27870==    by 0x55882E: cgraph_create_edge(cgraph_node*, cgraph_node*, gimple_statement_d*, long, int) (cgraph.c:890)
> > ==27870==    by 0x560891: cgraph_clone_edge(cgraph_edge*, cgraph_node*, gimple_statement_d*, unsigned int, long, int, bool) (cgraphclones.c:135)
> > ,,,
> >
> > This happens because e->indirect_unknown_callee may be uninitialized in
> > cgraph_add_edge_to_call_site_hash. Fixed by initializing it earlier.
> >
> > LTO bootstrapped and tested on x86_64-unknown-linux-gnu.
> >
> > Please apply, if this looks reasonable.
> 
> As we also have
> 
> struct cgraph_edge *
> cgraph_create_indirect_edge (struct cgraph_node *caller, gimple call_stmt,
>                              int ecf_flags,
>                              gcov_type count, int freq)
> {
>   struct cgraph_edge *edge = cgraph_create_edge_1 (caller, NULL, call_stmt,
>                                                    count, freq);
>   tree target;
> 
>   edge->indirect_unknown_callee = 1;
> 
> I'd rather change the cgraph_create_edge_1 interface to get an additional
> argument (the value to use for indirect_unknown_callee).  Or maybe
> we can statically compute it from the current arguments already?

IOW something like this:

diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index 124ee0adf855..ccd73fa21b80 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -814,7 +814,8 @@ cgraph_set_call_stmt (struct cgraph_edge *e, gimple new_stmt,
 
 static struct cgraph_edge *
 cgraph_create_edge_1 (struct cgraph_node *caller, struct cgraph_node *callee,
-		       gimple call_stmt, gcov_type count, int freq)
+		       gimple call_stmt, gcov_type count, int freq,
+		       bool indir_unknown_callee)
 {
   struct cgraph_edge *edge;
 
@@ -874,6 +875,7 @@ cgraph_create_edge_1 (struct cgraph_node *caller, struct cgraph_node *callee,
   edge->indirect_info = NULL;
   edge->indirect_inlining_edge = 0;
   edge->speculative = false;
+  edge->indirect_unknown_callee = indir_unknown_callee;
   if (call_stmt && caller->call_site_hash)
     cgraph_add_edge_to_call_site_hash (edge);
 
@@ -887,9 +889,8 @@ cgraph_create_edge (struct cgraph_node *caller, struct cgraph_node *callee,
 		    gimple call_stmt, gcov_type count, int freq)
 {
   struct cgraph_edge *edge = cgraph_create_edge_1 (caller, callee, call_stmt,
-						   count, freq);
+						   count, freq, false);
 
-  edge->indirect_unknown_callee = 0;
   initialize_inline_failed (edge);
 
   edge->next_caller = callee->callers;
@@ -926,10 +927,9 @@ cgraph_create_indirect_edge (struct cgraph_node *caller, gimple call_stmt,
 			     gcov_type count, int freq)
 {
   struct cgraph_edge *edge = cgraph_create_edge_1 (caller, NULL, call_stmt,
-						   count, freq);
+						   count, freq, true);
   tree target;
 
-  edge->indirect_unknown_callee = 1;
   initialize_inline_failed (edge);
 
   edge->indirect_info = cgraph_allocate_init_indirect_info ();

-- 
Markus


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