[PATCH] Avoid redundant indirect_info computation during inderct edge cloning

[Ilya Enkovich]

Hi,

I get a segafult in decl_maybe_in_construction_p during function versioning.  
We have following steps in clone creation (e.g. as in 
create_version_clone_with_body):
 1. Create function decl
 2. Create clone of cgraph node
 3. Copy function body
After the first step there is no body attached to function and 
DECL_STRUCT_FUNCTION for new decl is NULL.  It is initialized on the third 
step.  But on the second step get_polymorphic_call_info may be called for new 
function; it calls decl_maybe_in_construction_p which assumes 
DECL_STRUCT_FUNCTION already exists.

I firstly wanted to fix decl_maybe_in_construction_p but then realized 
cgraph_clone_edge copy indirect_info from the original edge anyway and 
therefore its computation is not required at all.

Following patch removes redundant indirect_info computation.  Bootstrapped and 
regtested on linux-x86_64.  Does it look OK for trunk?

Thanks,
Ilya
--
2014-08-15  Ilya Enkovich  <ilya.enkov...@intel.com>

        * cgraph.h (cgraph_node::create_indirect_edge): Add
        compute_indirect_info param.
        * cgraph.c (cgraph_node::create_indirect_edge): Compute
        indirect_info only when it is required.
        * cgraphclones.c (cgraph_clone_edge): Do not recompute
        indirect_info for cloned indirect edge.


diff --git a/gcc/cgraph.c b/gcc/cgraph.c
index 370a96a..cb49cdc 100644
--- a/gcc/cgraph.c
+++ b/gcc/cgraph.c
@@ -942,7 +942,8 @@ cgraph_allocate_init_indirect_info (void)
 
 struct cgraph_edge *
 cgraph_node::create_indirect_edge (gimple call_stmt, int ecf_flags,
-                                  gcov_type count, int freq)
+                                  gcov_type count, int freq,
+                                  bool compute_indirect_info)
 {
   struct cgraph_edge *edge = cgraph_node::create_edge (this, NULL, call_stmt,
                                                       count, freq, true);
@@ -954,7 +955,8 @@ cgraph_node::create_indirect_edge (gimple call_stmt, int 
ecf_flags,
   edge->indirect_info->ecf_flags = ecf_flags;
 
   /* Record polymorphic call info.  */
-  if (call_stmt
+  if (compute_indirect_info
+      && call_stmt
       && (target = gimple_call_fn (call_stmt))
       && virtual_method_call_p (target))
     {
diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 13c09af..2594ae5 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -915,7 +915,8 @@ public:
      statement destination is a formal parameter of the caller with index
      PARAM_INDEX. */
   struct cgraph_edge *create_indirect_edge (gimple call_stmt, int ecf_flags,
-                                           gcov_type count, int freq);
+                                           gcov_type count, int freq,
+                                           bool compute_indirect_info = true);
 
   /* Like cgraph_create_edge walk the clone tree and update all clones sharing
    same function body.  If clones already have edge for OLD_STMT; only
diff --git a/gcc/cgraphclones.c b/gcc/cgraphclones.c
index c04b5c8..557f734 100644
--- a/gcc/cgraphclones.c
+++ b/gcc/cgraphclones.c
@@ -136,7 +136,7 @@ cgraph_clone_edge (struct cgraph_edge *e, struct 
cgraph_node *n,
        {
          new_edge = n->create_indirect_edge (call_stmt,
                                              e->indirect_info->ecf_flags,
-                                             count, freq);
+                                             count, freq, false);
          *new_edge->indirect_info = *e->indirect_info;
        }
     }