Support ofsetted parameters in local modref

2020-10-14  Jan Hubicka  <hubicka@ucw.cz>

	* doc/invoke.texi: (ipa-jump-function-lookups): Document param.
	* ipa-modref.c (merge_call_side_effects): Use
	unadjusted_ptr_and_unit_offset.
	* ipa-prop.c (unadjusted_ptr_and_unit_offset): New function.
	* ipa-prop.h (unadjusted_ptr_and_unit_offset): Declare.
	* params.opt: (-param-ipa-jump-function-lookups): New.

gcc/doc/invoke.texi

@@ -13456,6 +13456,9 @@ loop in the loop nest by a given number of iterations.  The strip
 length can be changed using the @option{loop-block-tile-size}
 parameter.
 
+@item ipa-jump-function-lookups
+Specifies number of statements visited during jump function offset discovery.
+
 @item ipa-cp-value-list-size
 IPA-CP attempts to track all possible values and types passed to a function's
 parameter in order to propagate them and perform devirtualization.

gcc/ipa-modref.c

@@ -531,6 +531,10 @@ merge_call_side_effects (modref_summary *cur_summary,
   for (unsigned i = 0; i < gimple_call_num_args (stmt); i++)
     {
       tree op = gimple_call_arg (stmt, i);
+      bool offset_known;
+      poly_int64 offset;
+
+      offset_known = unadjusted_ptr_and_unit_offset (op, &op, &offset);
       if (TREE_CODE (op) == SSA_NAME
 	  && SSA_NAME_IS_DEFAULT_DEF (op)
 	  && TREE_CODE (SSA_NAME_VAR (op)) == PARM_DECL)
@@ -547,15 +551,23 @@ merge_call_side_effects (modref_summary *cur_summary,
 	      index++;
 	    }
 	  parm_map[i].parm_index = index;
-	  parm_map[i].parm_offset_known = true;
-	  parm_map[i].parm_offset = 0;
+	  parm_map[i].parm_offset_known = offset_known;
+	  parm_map[i].parm_offset = offset;
 	}
       else if (points_to_local_or_readonly_memory_p (op))
 	parm_map[i].parm_index = -2;
       else
 	parm_map[i].parm_index = -1;
       if (dump_file)
-	fprintf (dump_file, " %i", parm_map[i].parm_index);
+	{
+	  fprintf (dump_file, " %i", parm_map[i].parm_index);
+	  if (parm_map[i].parm_offset_known)
+	    {
+	      fprintf (dump_file, " offset:");
+	      print_dec ((poly_int64_pod)parm_map[i].parm_offset,
+			 dump_file, SIGNED);
+	    }
+	}
     }
   if (dump_file)
     fprintf (dump_file, "\n");

gcc/ipa-prop.c

@@ -52,6 +52,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "domwalk.h"
 #include "builtins.h"
 #include "tree-cfgcleanup.h"
+#include "options.h"
 
 /* Function summary where the parameter infos are actually stored. */
 ipa_node_params_t *ipa_node_params_sum = NULL;
@@ -1222,6 +1223,73 @@ load_from_unmodified_param_or_agg (struct ipa_func_body_info *fbi,
   return index;
 }
 
+/* Walk pointer adjustemnts from OP (such as POINTER_PLUS and ADDR_EXPR)
+   to find original pointer.  Initialize RET to the pointer which results from
+   the walk.
+   If offset is known return true and initialize OFFSET_RET.  */
+
+bool
+unadjusted_ptr_and_unit_offset (tree op, tree *ret, poly_int64 *offset_ret)
+{
+  poly_int64 offset = 0;
+  bool offset_known = true;
+  int i;
+
+  for (i = 0; i < param_ipa_jump_function_lookups; i++)
+    {
+      if (TREE_CODE (op) == ADDR_EXPR)
+	{
+	  poly_int64 extra_offset = 0;
+	  tree base = get_addr_base_and_unit_offset (TREE_OPERAND (op, 0),
+						     &offset);
+	  if (!base)
+	    {
+	      base = get_base_address (TREE_OPERAND (op, 0));
+	      if (TREE_CODE (base) != MEM_REF)
+		break;
+	      offset_known = false;
+	    }
+	  else
+	    {
+	      if (TREE_CODE (base) != MEM_REF)
+		break;
+	      offset += extra_offset;
+	    }
+	  op = TREE_OPERAND (base, 0);
+	  if (mem_ref_offset (base).to_shwi (&extra_offset))
+	    offset += extra_offset;
+	  else
+	    offset_known = false;
+	}
+      else if (TREE_CODE (op) == SSA_NAME
+	       && !SSA_NAME_IS_DEFAULT_DEF (op))
+	{
+	  gimple *pstmt = SSA_NAME_DEF_STMT (op);
+
+	  if (gimple_assign_single_p (pstmt))
+	    op = gimple_assign_rhs1 (pstmt);
+	  else if (is_gimple_assign (pstmt)
+		   && gimple_assign_rhs_code (pstmt) == POINTER_PLUS_EXPR)
+	    {
+	      poly_int64 extra_offset = 0;
+	      if (ptrdiff_tree_p (gimple_assign_rhs2 (pstmt),
+		  &extra_offset))
+		offset += extra_offset;
+	      else
+		offset_known = false;
+	      op = gimple_assign_rhs1 (pstmt);
+	    }
+	  else
+	    break;
+	}
+      else
+	break;
+    }
+  *ret = op;
+  *offset_ret = offset;
+  return offset_known;
+}
+
 /* Given that an actual argument is an SSA_NAME (given in NAME) and is a result
    of an assignment statement STMT, try to determine whether we are actually
    handling any of the following cases and construct an appropriate jump

gcc/ipa-prop.h

@@ -1144,6 +1144,8 @@ void ipa_dump_param (FILE *, class ipa_node_params *info, int i);
 void ipa_release_body_info (struct ipa_func_body_info *);
 tree ipa_get_callee_param_type (struct cgraph_edge *e, int i);
 bool ipcp_get_parm_bits (tree, tree *, widest_int *);
+bool unadjusted_ptr_and_unit_offset (tree op, tree *ret,
+				     poly_int64 *offset_ret);
 
 /* From tree-sra.c:  */
 tree build_ref_for_offset (location_t, tree, poly_int64, bool, tree,

gcc/params.opt

@@ -253,6 +253,10 @@ The size of translation unit that IPA-CP pass considers large.
 Common Joined UInteger Var(param_ipa_cp_value_list_size) Init(8) Param Optimization
 Maximum size of a list of values associated with each parameter for interprocedural constant propagation.
 
+-param-ipa-jump-function-lookups=
+Common Joined UInteger Var(param_ipa_jump_function_lookups) Init(8) Param Optimization
+Maximum number of statements visited during jump function offset discovery
+
 -param=ipa-max-aa-steps=
 Common Joined UInteger Var(param_ipa_max_aa_steps) Init(25000) Param Optimization
 Maximum number of statements that will be visited by IPA formal parameter analysis based on alias analysis in any given function.