tree-ssa-structalias.c: Include tree-cfg.h.

2019-06-06  Richard Biener  <rguenther@suse.de>

	* tree-ssa-structalias.c: Include tree-cfg.h.
	(make_heapvar): Do not make heap vars artificial.
	(find_func_aliases_for_builtin_call): Handle stack allocation
	functions.
	(find_func_aliases): Delay processing of simple enough returns
	in non-IPA mode.
	(set_uids_in_ptset): Adjust.
	(find_what_var_points_to): Likewise.
	(solve_constraints): Do not dump points-to sets here.
	(compute_points_to_sets): Post-process return statements,
	amending the escaped solution.  Dump points-to sets afterwards.
	(ipa_pta_execute): Dump points-to sets.

	* gcc.dg/tree-ssa/alias-37.c: New testcase.
	* gcc.dg/torture/20190604-1.c: Likewise.
	* gcc.dg/tree-ssa/pta-callused.c: Adjust.

From-SVN: r271989

1 files changed, 104 insertions, 11 deletions

diff --git a/gcc/tree-ssa-structalias.c b/gcc/tree-ssa-structalias.c
index d8ff2ce6..0779151 100644
--- a/gcc/tree-ssa-structalias.c
+++ b/gcc/tree-ssa-structalias.c
@@ -43,6 +43,7 @@
 #include "stringpool.h"
 #include "attribs.h"
 #include "tree-ssa.h"
+#include "tree-cfg.h"
 
 /* The idea behind this analyzer is to generate set constraints from the
    program, then solve the resulting constraints in order to generate the
@@ -3854,7 +3855,6 @@ make_heapvar (const char *name, bool add_id)
   DECL_EXTERNAL (heapvar) = 1;
 
   vi = new_var_info (heapvar, name, add_id);
-  vi->is_artificial_var = true;
   vi->is_heap_var = true;
   vi->is_unknown_size_var = true;
   vi->offset = 0;
@@ -4409,6 +4409,32 @@ find_func_aliases_for_builtin_call (struct function *fn, gcall *t)
 	      process_constraint (new_constraint (*lhsp, ac));
 	  return true;
 	}
+      case BUILT_IN_STACK_SAVE:
+      case BUILT_IN_STACK_RESTORE:
+        /* Nothing interesting happens.  */
+        return true;
+      case BUILT_IN_ALLOCA:
+      case BUILT_IN_ALLOCA_WITH_ALIGN:
+      case BUILT_IN_ALLOCA_WITH_ALIGN_AND_MAX:
+	{
+	  tree ptr = gimple_call_lhs (t);
+	  if (ptr == NULL_TREE)
+	    return true;
+	  get_constraint_for (ptr, &lhsc);
+	  varinfo_t vi = make_heapvar ("HEAP", true);
+	  /* Alloca storage is never global.  To exempt it from escaped
+	     handling make it a non-heap var.  */
+	  DECL_EXTERNAL (vi->decl) = 0;
+	  vi->is_global_var = 0;
+	  vi->is_heap_var = 0;
+	  struct constraint_expr tmpc;
+	  tmpc.var = vi->id;
+	  tmpc.offset = 0;
+	  tmpc.type = ADDRESSOF;
+	  rhsc.safe_push (tmpc);
+	  process_all_all_constraints (lhsc, rhsc);
+	  return true;
+	}
       case BUILT_IN_POSIX_MEMALIGN:
         {
 	  tree ptrptr = gimple_call_arg (t, 0);
@@ -4976,7 +5002,12 @@ find_func_aliases (struct function *fn, gimple *origt)
       greturn *return_stmt = as_a <greturn *> (t);
       fi = NULL;
       if (!in_ipa_mode
-	  || !(fi = get_vi_for_tree (fn->decl)))
+	  && SSA_VAR_P (gimple_return_retval (return_stmt)))
+	{
+	  /* We handle simple returns by post-processing the solutions.  */
+	  ;
+	}
+      if (!(fi = get_vi_for_tree (fn->decl)))
 	make_escape_constraint (gimple_return_retval (return_stmt));
       else if (in_ipa_mode)
 	{
@@ -6422,9 +6453,7 @@ set_uids_in_ptset (bitmap into, bitmap from, struct pt_solution *pt,
     {
       varinfo_t vi = get_varinfo (i);
 
-      /* The only artificial variables that are allowed in a may-alias
-	 set are heap variables.  */
-      if (vi->is_artificial_var && !vi->is_heap_var)
+      if (vi->is_artificial_var)
 	continue;
 
       if (everything_escaped
@@ -6544,9 +6573,6 @@ find_what_var_points_to (tree fndecl, varinfo_t orig_vi)
 	    }
 	  else if (vi->id == nonlocal_id)
 	    pt->nonlocal = 1;
-	  else if (vi->is_heap_var)
-	    /* We represent heapvars in the points-to set properly.  */
-	    ;
 	  else if (vi->id == string_id)
 	    /* Nobody cares - STRING_CSTs are read-only entities.  */
 	    ;
@@ -7254,9 +7280,6 @@ solve_constraints (void)
       dump_constraint_graph (dump_file);
       fprintf (dump_file, "\n\n");
     }
-
-  if (dump_file)
-    dump_sa_points_to_info (dump_file);
 }
 
 /* Create points-to sets for the current function.  See the comments
@@ -7304,6 +7327,73 @@ compute_points_to_sets (void)
   /* From the constraints compute the points-to sets.  */
   solve_constraints ();
 
+  /* Post-process solutions for escapes through returns.  */
+  edge_iterator ei;
+  edge e;
+  FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR_FOR_FN (cfun)->preds)
+    if (greturn *ret = safe_dyn_cast <greturn *> (last_stmt (e->src)))
+      {
+	tree val = gimple_return_retval (ret);
+	/* ???  Easy to handle simple indirections with some work.
+	   Arbitrary references like foo.bar.baz are more difficult
+	   (but conservatively easy enough with just looking at the base).
+	   Mind to fixup find_func_aliases as well.  */
+	if (!val || !SSA_VAR_P (val))
+	  continue;
+	/* returns happen last in non-IPA so they only influence
+	   the ESCAPED solution and we can filter local variables.  */
+	varinfo_t escaped_vi = get_varinfo (find (escaped_id));
+	varinfo_t vi = lookup_vi_for_tree (val);
+	bitmap delta = BITMAP_ALLOC (&pta_obstack);
+	bitmap_iterator bi;
+	unsigned i;
+	for (; vi; vi = vi_next (vi))
+	  {
+	    varinfo_t part_vi = get_varinfo (find (vi->id));
+	    EXECUTE_IF_AND_COMPL_IN_BITMAP (part_vi->solution,
+					    escaped_vi->solution, 0, i, bi)
+	      {
+		varinfo_t pointed_to_vi = get_varinfo (i);
+		if (pointed_to_vi->is_global_var
+		    /* We delay marking of heap memory as global.  */
+		    || pointed_to_vi->is_heap_var)
+		  bitmap_set_bit (delta, i);
+	      }
+	  }
+
+	/* Now compute the transitive closure.  */
+	bitmap_ior_into (escaped_vi->solution, delta);
+	bitmap new_delta = BITMAP_ALLOC (&pta_obstack);
+	while (!bitmap_empty_p (delta))
+	  {
+	    EXECUTE_IF_SET_IN_BITMAP (delta, 0, i, bi)
+	      {
+		varinfo_t pointed_to_vi = get_varinfo (i);
+		pointed_to_vi = get_varinfo (find (pointed_to_vi->id));
+		unsigned j;
+		bitmap_iterator bi2;
+		EXECUTE_IF_AND_COMPL_IN_BITMAP (pointed_to_vi->solution,
+						escaped_vi->solution,
+						0, j, bi2)
+		  {
+		    varinfo_t pointed_to_vi2 = get_varinfo (j);
+		    if (pointed_to_vi2->is_global_var
+			/* We delay marking of heap memory as global.  */
+			|| pointed_to_vi2->is_heap_var)
+		      bitmap_set_bit (new_delta, j);
+		  }
+	      }
+	    bitmap_ior_into (escaped_vi->solution, new_delta);
+	    bitmap_clear (delta);
+	    std::swap (delta, new_delta);
+	  }
+	BITMAP_FREE (delta);
+	BITMAP_FREE (new_delta);
+      }
+
+  if (dump_file)
+    dump_sa_points_to_info (dump_file);
+
   /* Compute the points-to set for ESCAPED used for call-clobber analysis.  */
   cfun->gimple_df->escaped = find_what_var_points_to (cfun->decl,
 						      get_varinfo (escaped_id));
@@ -8109,6 +8199,9 @@ ipa_pta_execute (void)
   /* From the constraints compute the points-to sets.  */
   solve_constraints ();
 
+  if (dump_file)
+    dump_sa_points_to_info (dump_file);
+
   /* Now post-process solutions to handle locals from different
      runtime instantiations coming in through recursive invocations.  */
   unsigned shadow_var_cnt = 0;