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Commit bf6fc129 by Jan Hubicka
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Implement speculative call verifier 

this patch implements verifier and fixes one bug where speculative calls
produced by ipa-devirt ended up having num_speculative_call_targets = 0
instead of 1.

	* cgraph.c (cgraph_edge::make_speculative): Increase number of
	speculative targets.
	(verify_speculative_call): New function
	(cgraph_node::verify_node): Use it.
	* ipa-profile.c (ipa_profile): Fix formating; do not set number of
	speculations.
parent 118aa5e3
Showing with 241 additions and 94 deletions
gcc/ChangeLog
2020-01-18 Jan Hubicka <hubicka@ucw.cz>
PR lto/93318
* cgraph.c (cgraph_edge::make_speculative): Increase number of
speculative targets.
(verify_speculative_call): New function
(cgraph_node::verify_node): Use it.
* ipa-profile.c (ipa_profile): Fix formating; do not set number of
speculations.
2020-01-18 Jan Hubicka <hubicka@ucw.cz>
PR lto/93318
* cgraph.c (cgraph_edge::resolve_speculation): Fix foramting.
(cgraph_edge::make_direct): Remove all indirect targets.
(cgraph_edge::redirect_call_stmt_to_callee): Use make_direct..
......
gcc/cgraph.c
......@@ -1076,6 +1076,7 @@ cgraph_edge::make_speculative (cgraph_node *n2, profile_count direct_count,
e2->speculative_id = speculative_id;
e2->target_prob = target_prob;
e2->in_polymorphic_cdtor = in_polymorphic_cdtor;
indirect_info->num_speculative_call_targets++;
count -= e2->count;
symtab->call_edge_duplication_hooks (this, e2);
ref = n->create_reference (n2, IPA_REF_ADDR, call_stmt);
......@@ -3148,6 +3149,128 @@ cgraph_edge::verify_corresponds_to_fndecl (tree decl)
# pragma GCC diagnostic ignored "-Wformat-diag"
#endif
/* Verify consistency of speculative call in NODE corresponding to STMT
and LTO_STMT_UID. If INDIRECT is set, assume that it is the indirect
edge of call sequence. Return true if error is found.
This function is called to every component of indirect call (direct edges,
indirect edge and refs). To save duplicated work, do full testing only
in that case. */
static bool
verify_speculative_call (struct cgraph_node *node, gimple *stmt,
unsigned int lto_stmt_uid,
struct cgraph_edge *indirect)
{
if (indirect == NULL)
{
for (indirect = node->indirect_calls; indirect;
indirect = indirect->next_callee)
if (indirect->call_stmt == stmt
&& indirect->lto_stmt_uid == lto_stmt_uid)
break;
if (!indirect)
{
error ("missing indirect call in speculative call sequence");
return true;
}
if (!indirect->speculative)
{
error ("indirect call in speculative call sequence has no "
"speculative flag");
return true;
}
return false;
}
/* Maximal number of targets. We probably will never want to have more than
this. */
const unsigned int num = 256;
cgraph_edge *direct_calls[num];
ipa_ref *refs[num];
for (unsigned int i = 0; i < num; i++)
{
direct_calls[i] = NULL;
refs[i] = NULL;
}
for (cgraph_edge *direct = node->callees; direct;
direct = direct->next_callee)
if (direct->call_stmt == stmt && direct->lto_stmt_uid == lto_stmt_uid)
{
if (!direct->speculative)
{
error ("direct call to %s in speculative call sequence has no "
"speculative flag", direct->callee->dump_name ());
return true;
}
if (direct->speculative_id >= num)
{
error ("direct call to %s in speculative call sequence has "
"speculative_uid %i out of range",
direct->callee->dump_name (), direct->speculative_id);
return true;
}
if (direct_calls[direct->speculative_id])
{
error ("duplicate direct call to %s in speculative call sequence "
"with speculative_uid %i",
direct->callee->dump_name (), direct->speculative_id);
return true;
}
direct_calls[direct->speculative_id] = direct;
}
ipa_ref *ref;
for (int i = 0; node->iterate_reference (i, ref); i++)
if (ref->speculative
&& ref->stmt == stmt && ref->lto_stmt_uid == lto_stmt_uid)
{
if (ref->speculative_id >= num)
{
error ("direct call to %s in speculative call sequence has "
"speculative_uid %i out of range",
ref->referred->dump_name (), ref->speculative_id);
return true;
}
if (refs[ref->speculative_id])
{
error ("duplicate reference %s in speculative call sequence "
"with speculative_uid %i",
ref->referred->dump_name (), ref->speculative_id);
return true;
}
refs[ref->speculative_id] = ref;
}
int num_targets = 0;
for (unsigned int i = 0 ; i < num ; i++)
{
if (refs[i] && !direct_calls[i])
{
error ("missing direct call for speculation %i", i);
return true;
}
if (!refs[i] && direct_calls[i])
{
error ("missing ref for speculation %i", i);
return true;
}
if (refs[i] != NULL)
num_targets++;
}
if (num_targets != indirect->num_speculative_call_targets_p ())
{
error ("number of speculative targets %i mismatched with "
"num_speculative_targets %i",
num_targets,
indirect->num_speculative_call_targets_p ());
return true;
}
return false;
}
/* Verify cgraph nodes of given cgraph node. */
DEBUG_FUNCTION void
cgraph_node::verify_node (void)
......@@ -3320,6 +3443,10 @@ cgraph_node::verify_node (void)
error ("edge has both cal_stmt and lto_stmt_uid set");
error_found = true;
}
if (e->speculative
&& verify_speculative_call (e->caller, e->call_stmt, e->lto_stmt_uid,
NULL))
error_found = true;
}
for (e = indirect_calls; e; e = e->next_callee)
{
......@@ -3342,7 +3469,24 @@ cgraph_node::verify_node (void)
fprintf (stderr, "\n");
error_found = true;
}
if (e->speculative
&& verify_speculative_call (e->caller, e->call_stmt, e->lto_stmt_uid,
e))
error_found = true;
}
for (i = 0; iterate_reference (i, ref); i++)
{
if (ref->stmt && ref->lto_stmt_uid)
{
error ("reference has both cal_stmt and lto_stmt_uid set");
error_found = true;
}
if (ref->speculative
&& verify_speculative_call (this, ref->stmt,
ref->lto_stmt_uid, NULL))
error_found = true;
}
if (!callers && inlined_to)
{
error ("inlined_to pointer is set but no predecessors found");
......@@ -3519,13 +3663,6 @@ cgraph_node::verify_node (void)
/* No CFG available?! */
gcc_unreachable ();
for (i = 0; iterate_reference (i, ref); i++)
if (ref->stmt && ref->lto_stmt_uid)
{
error ("reference has both cal_stmt and lto_stmt_uid set");
error_found = true;
}
for (e = callees; e; e = e->next_callee)
{
if (!e->aux && !e->speculative)
......
gcc/ipa-profile.c
......@@ -864,104 +864,104 @@ ipa_profile (void)
}
unsigned speculative_id = 0;
bool speculative_found = false;
for (unsigned i = 0; i < spec_count; i++)
{
speculative_call_target item
= csum->speculative_call_targets[i];
n2 = find_func_by_profile_id (item.target_id);
if (n2)
{
if (dump_file)
{
fprintf (dump_file, "Indirect call -> direct call from"
" other module %s => %s, prob %3.2f\n",
n->dump_name (),
n2->dump_name (),
item.target_probability
/ (float) REG_BR_PROB_BASE);
}
if (item.target_probability < REG_BR_PROB_BASE / 2)
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: probability is too low.\n");
}
else if (!e->maybe_hot_p ())
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: call is cold.\n");
}
else if (n2->get_availability () <= AVAIL_INTERPOSABLE
&& n2->can_be_discarded_p ())
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: target is overwritable "
"and can be discarded.\n");
}
else if (!check_argument_count (n2, e))
speculative_call_target item
= csum->speculative_call_targets[i];
n2 = find_func_by_profile_id (item.target_id);
if (n2)
{
nmismatch++;
if (dump_file)
fprintf (dump_file,
"Not speculating: "
"parameter count mismatch\n");
{
fprintf (dump_file,
"Indirect call -> direct call from"
" other module %s => %s, prob %3.2f\n",
n->dump_name (),
n2->dump_name (),
item.target_probability
/ (float) REG_BR_PROB_BASE);
}
if (item.target_probability < REG_BR_PROB_BASE / 2)
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: "
"probability is too low.\n");
}
else if (!e->maybe_hot_p ())
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: call is cold.\n");
}
else if (n2->get_availability () <= AVAIL_INTERPOSABLE
&& n2->can_be_discarded_p ())
{
nuseless++;
if (dump_file)
fprintf (dump_file,
"Not speculating: target is overwritable "
"and can be discarded.\n");
}
else if (!check_argument_count (n2, e))
{
nmismatch++;
if (dump_file)
fprintf (dump_file,
"Not speculating: "
"parameter count mismatch\n");
}
else if (e->indirect_info->polymorphic
&& !opt_for_fn (n->decl, flag_devirtualize)
&& !possible_polymorphic_call_target_p (e, n2))
{
nimpossible++;
if (dump_file)
fprintf (dump_file,
"Not speculating: "
"function is not in the polymorphic "
"call target list\n");
}
else
{
/* Target may be overwritable, but profile says that
control flow goes to this particular implementation
of N2. Speculate on the local alias to allow
inlining. */
if (!n2->can_be_discarded_p ())
{
cgraph_node *alias;
alias = dyn_cast<cgraph_node *>
(n2->noninterposable_alias ());
if (alias)
n2 = alias;
}
nconverted++;
e->make_speculative (n2,
e->count.apply_probability (
item.target_probability),
speculative_id,
item.target_probability);
update = true;
speculative_id++;
}
}
else if (e->indirect_info->polymorphic
&& !opt_for_fn (n->decl, flag_devirtualize)
&& !possible_polymorphic_call_target_p (e, n2))
else
{
nimpossible++;
if (dump_file)
fprintf (dump_file,
"Not speculating: "
"function is not in the polymorphic "
"call target list\n");
}
else
{
/* Target may be overwritable, but profile says that
control flow goes to this particular implementation
of N2. Speculate on the local alias to allow inlining.
*/
if (!n2->can_be_discarded_p ())
{
cgraph_node *alias;
alias = dyn_cast<cgraph_node *> (n2->noninterposable_alias ());
if (alias)
n2 = alias;
}
nconverted++;
e->make_speculative (n2,
e->count.apply_probability (
item.target_probability),
speculative_id,
item.target_probability);
update = true;
speculative_id++;
speculative_found = true;
"Function with profile-id %i not found.\n",
item.target_id);
nunknown++;
}
}
else
{
if (dump_file)
fprintf (dump_file, "Function with profile-id %i not found.\n",
item.target_id);
nunknown++;
}
}
if (speculative_found)
e->indirect_info->num_speculative_call_targets = speculative_id;
}
}
if (update)
ipa_update_overall_fn_summary (n);
}
}
if (update)
ipa_update_overall_fn_summary (n);
}
if (node_map_initialized)
del_node_map ();
if (dump_file && nindirect)
......
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