analyzer: revamp side-effects of call summaries [PR107072]

With -fanalyzer-call-summaries the analyzer canl attempt to summarize
the effects of some function calls at their call site, rather than
simulate the call directly, which can avoid big slowdowns during
analysis.

Previously, this summarization was extremely simplistic: no attempt
was made to update sm-state, and region_model::update_for_call_summary
would simply set the return value of the function to UNKNOWN, and assume
the function had no side effects.

This patch implements less simplistic summarizations: it tracks each
possible return enode from the called function, and attempts to generate
a successor enode from the callsite for each that have compatible
conditions, mapping state changes in the summary to state changes
at the callsite.  It also implements the beginnings of heuristics for
generating user-facing descriptions of a summary e.g.
  "when 'foo' returns NULL"
versus:
  "when 'foo' returns a heap-allocated buffer"

This still has some bugs, but much more accurately tracks the effects
of a call, and so is an improvement; it should only have an effect
when -fanalyzer-call-summaries is enabled.

As before, -fanalyzer-call-summaries is disabled by default in
analyzer.opt (but enabled by default in the test suite).

gcc/ChangeLog:
	PR analyzer/107072
	* Makefile.in (ANALYZER_OBJS): Add analyzer/call-summary.o.

gcc/analyzer/ChangeLog:
	PR analyzer/107072
	* analyzer-logging.h: Include "diagnostic-core.h".
	* analyzer.h: Include "function.h".
	(class call_summary): New forward decl.
	(class call_summary_replay): New forward decl.
	(struct per_function_data): New forward decl.
	(struct interesting_t): New forward decl.
	(custom_edge_info::update_state): New vfunc.
	* call-info.cc (custom_edge_info::update_state): New.
	* call-summary.cc: New file.
	* call-summary.h: New file.
	* constraint-manager.cc: Include "analyzer/call-summary.h".
	(class replay_fact_visitor): New.
	(constraint_manager::replay_call_summary): New.
	* constraint-manager.h (constraint_manager::replay_call_summary):
	New.
	* engine.cc: Include "analyzer/call-summary.h".
	(exploded_node::on_stmt): Handle call summaries.
	(class call_summary_edge_info): New.
	(exploded_node::replay_call_summaries): New.
	(exploded_node::replay_call_summary): New.
	(per_function_data::~per_function_data): New.
	(per_function_data::add_call_summary): Move here from header and
	reimplement.
	(exploded_graph::process_node): Call update_state rather than
	update_model when handling bifurcation
	(viz_callgraph_node::dump_dot): Use a regular label rather
	than an HTML table; add summaries to dump.
	* exploded-graph.h: Include "alloc-pool.h", "fibonacci_heap.h",
	"supergraph.h", "sbitmap.h", "shortest-paths.h", "analyzer/sm.h",
	"analyzer/program-state.h", and "analyzer/diagnostic-manager.h".
	(exploded_node::replay_call_summaries): New decl.
	(exploded_node::replay_call_summary): New decl.
	(per_function_data::~per_function_data): New decl.
	(per_function_data::add_call_summary): Move implemention from
	header.
	(per_function_data::m_summaries): Update type of element.
	* known-function-manager.h: Include "analyzer/analyzer-logging.h".
	* program-point.h: Include "pretty-print.h" and
	"analyzer/call-string.h".
	* program-state.cc: Include "analyzer/call-summary.h".
	(sm_state_map::replay_call_summary): New.
	(program_state::replay_call_summary): New.
	* program-state.h (sm_state_map::replay_call_summary): New decl.
	(program_state::replay_call_summary): New decl.
	* region-model-manager.cc
	(region_model_manager::get_or_create_asm_output_svalue): New
	overload.
	* region-model-manager.h
	(region_model_manager::get_or_create_asm_output_svalue): New
	overload decl.
	* region-model.cc: Include "analyzer/call-summary.h".
	(region_model::maybe_update_for_edge): Remove call to
	region_model::update_for_call_summary on
	SUPEREDGE_INTRAPROCEDURAL_CALL.
	(region_model::update_for_call_summary): Delete.
	(region_model::replay_call_summary): New.
	* region-model.h (region_model::replay_call_summary): New decl.
	(region_model::update_for_call_summary): Delete decl.
	* store.cc: Include "analyzer/call-summary.h".
	(store::replay_call_summary): New.
	(store::replay_call_summary_cluster): New.
	* store.h: Include "tristate.h".
	(is_a_helper <const ana::concrete_binding *>::test): New.
	(store::replay_call_summary): New decl.
	(store::replay_call_summary_cluster): New decl.
	* supergraph.cc (get_ultimate_function_for_cgraph_edge): Remove
	"static" from decl.
	(supergraph_call_edge): Make stmt param const.
	* supergraph.h: Include "ordered-hash-map.h", "cfg.h",
	"basic-block.h", "gimple.h", "gimple-iterator.h", and "digraph.h".
	(supergraph_call_edge): Make stmt param const.
	(get_ultimate_function_for_cgraph_edge): New decl.
	* svalue.cc (compound_svalue::compound_svalue): Assert that we're
	not nesting compound_svalues.
	* svalue.h: Include "json.h", "analyzer/store.h", and
	"analyzer/program-point.h".
	(asm_output_svalue::get_num_outputs): New accessor.

gcc/testsuite/ChangeLog:
	PR analyzer/107072
	* gcc.dg/analyzer/call-summaries-2.c: New test.
	* gcc.dg/analyzer/call-summaries-3.c: New test.
	* gcc.dg/analyzer/call-summaries-asm-x86.c: New test.
	* gcc.dg/analyzer/call-summaries-malloc.c: New test.
	* gcc.dg/analyzer/call-summaries-pr107072.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/gcc/analyzer/store.h b/gcc/analyzer/store.h
index d172ee75..0b5cbd6 100644
--- a/gcc/analyzer/store.h
+++ b/gcc/analyzer/store.h
@@ -21,6 +21,8 @@ along with GCC; see the file COPYING3.  If not see
 #ifndef GCC_ANALYZER_STORE_H
 #define GCC_ANALYZER_STORE_H
 
+#include "tristate.h"
+
 /* Implementation of the region-based ternary model described in:
      "A Memory Model for Static Analysis of C Programs"
       (Zhongxing Xu, Ted Kremenek, and Jian Zhang)
@@ -418,6 +420,14 @@ private:
 
 } // namespace ana
 
+template <>
+template <>
+inline bool
+is_a_helper <const ana::concrete_binding *>::test (const ana::binding_key *key)
+{
+  return key->concrete_p ();
+}
+
 template <> struct default_hash_traits<ana::concrete_binding>
 : public member_function_hash_traits<ana::concrete_binding>
 {
@@ -786,6 +796,12 @@ public:
   void loop_replay_fixup (const store *other_store,
 			  region_model_manager *mgr);
 
+  void replay_call_summary (call_summary_replay &r,
+			    const store &summary);
+  void replay_call_summary_cluster (call_summary_replay &r,
+				    const store &summary,
+				    const region *base_reg);
+
 private:
   void remove_overlapping_bindings (store_manager *mgr, const region *reg,
 				    uncertainty_t *uncertainty);