PR debug/47858

	* gimple.h (enum gimple_debug_subcode): Add GIMPLE_DEBUG_SOURCE_BIND.
	(gimple_build_debug_source_bind_stat): New prototype.
	(gimple_build_debug_source_bind): Define.
	(gimple_debug_source_bind_p, gimple_debug_source_bind_get_var,
	gimple_debug_source_bind_get_value,
	gimple_debug_source_bind_get_value_ptr,
	gimple_debug_source_bind_set_var,
	gimple_debug_source_bind_set_value): New inlines.
	* gimple.c (gimple_build_debug_source_bind_stat): New function.
	* gimple-pretty-print.c (dump_gimple_debug): Handle
	GIMPLE_DEBUG_SOURCE_BIND.
	* sese.c (rename_uses): Handle gimple_debug_source_bind_p.
	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Likewise.
	* tree-parloops.c (eliminate_local_variables,
	separate_decls_in_region): Likewise.
	(separate_decls_in_region_debug): Renamed from
	separate_decls_in_region_debug_bind.  Handle
	gimple_debug_source_bind_p.
	* tree.h (decl_debug_args_lookup, decl_debug_args_insert): New
	prototypes.
	(DECL_HAS_DEBUG_ARGS_P): Define.
	(struct tree_function_decl): Add has_debug_args_flag field.
	* tree.c (debug_args_for_decl): New variable.
	(decl_debug_args_lookup, decl_debug_args_insert): New functions.
	* tree-into-ssa.c (mark_def_sites): Handle uses in debug stmts.
	(rewrite_debug_stmt_uses): New function.
	(rewrite_stmt): Use it to rewrite debug stmt uses.
	* rtl.def (DEBUG_PARAMETER_REF): New.
	* rtl.h (DEBUG_PARAMETER_REF_DECL): Define.
	* cselib.c (rtx_equal_for_cselib_1, cselib_hash_rtx): Handle
	DEBUG_PARAMETER_REF.
	* rtl.c (rtx_equal_p_cb, rtx_equal_p, iterative_hash_rtx): Likewise.
	* print-rtl.c (print_rtx): Likewise.
	* tree-sra.c (sra_ipa_reset_debug_stmts): Prefer replacing of
	SSA_NAMEs with DEBUG_EXPR_DECLs initialized in source bind
	debug stmts in the first bb.
	* tree-inline.c (remap_ssa_name): If remapping default def
	of a PARM_DECL fails, map to a DEBUG_EXPR_DECL set in
	a source bind debug stmt.
	(remap_gimple_stmt): Handle gimple_debug_source_bind_p.
	(maybe_move_debug_stmts_to_successors): Likewise.
	(copy_debug_stmt): Likewise.  Avoid shadowing a variable.
	(tree_function_versioning): If DECL_HAS_DEBUG_ARGS_P, copy
	debug args vector from old_decl to new_decl.
	* ipa-prop.c (ipa_modify_call_arguments): For optimized away
	or modified parameters, add debug bind stmts before call
	setting DEBUG_EXPR_DECL which is remembered in debug args
	vector.
	* cfgexpand.c (expand_call_stmt): Call expand_debug_expr
	on DECL_DEBUG_EXPRs from debug args vector.
	(expand_debug_source_expr): New function.
	(expand_debug_locations): Use it for source bind insns.
	(expand_gimple_basic_block): Handle gimple_debug_source_bind_p.
	* var-tracking.c (prepare_call_arguments): Add debug args
	to call_arguments if any.
	* dwarf2out.c (dwarf_stack_op_name, size_of_loc_descr,
	output_loc_operands, output_loc_operands_raw,
	resolve_addr_in_expr, compare_loc_operands): Handle
	DW_OP_GNU_parameter_ref.
	(get_ref_die_offset, parameter_ref_descriptor): New functions.
	(mem_loc_descriptor): Handle DEBUG_PARAMETER_REF.
	(gen_subprogram_die): Handle parameters identified by
	DEBUG_PARAMETER_REF.

	* dwarf2.h (enum dwarf_location_atom): Add DW_OP_GNU_parameter_ref.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@175288 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 90 insertions, 8 deletions

diff --git a/gcc/tree-into-ssa.c b/gcc/tree-into-ssa.c
index f138e5b72c9..0db9085f053 100644
--- a/gcc/tree-into-ssa.c
+++ b/gcc/tree-into-ssa.c
@@ -1,5 +1,5 @@
 /* Rewrite a program in Normal form into SSA.
-   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
+   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Diego Novillo <dnovillo@redhat.com>
 
@@ -745,7 +745,17 @@ mark_def_sites (basic_block bb, gimple stmt, bitmap kills)
   set_rewrite_uses (stmt, false);
 
   if (is_gimple_debug (stmt))
-    return;
+    {
+      FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+	{
+	  tree sym = USE_FROM_PTR (use_p);
+	  gcc_assert (DECL_P (sym));
+	  set_rewrite_uses (stmt, true);
+	}
+      if (rewrite_uses_p (stmt))
+	SET_BIT (interesting_blocks, bb->index);
+      return;
+    }
 
   /* If a variable is used before being set, then the variable is live
      across a block boundary, so mark it live-on-entry to BB.  */
@@ -1279,6 +1289,73 @@ get_reaching_def (tree var)
 }
 
 
+/* Helper function for rewrite_stmt.  Rewrite uses in a debug stmt.  */
+
+static void
+rewrite_debug_stmt_uses (gimple stmt)
+{
+  use_operand_p use_p;
+  ssa_op_iter iter;
+  bool update = false;
+
+  FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+    {
+      tree var = USE_FROM_PTR (use_p), def = NULL_TREE;
+      gcc_assert (DECL_P (var));
+      if (var_ann (var) == NULL)
+	{
+	  if (TREE_CODE (var) == PARM_DECL && single_succ_p (ENTRY_BLOCK_PTR))
+	    {
+	      gimple_stmt_iterator gsi
+		= gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
+	      int lim;
+	      /* Search a few source bind stmts at the start of first bb to
+		 see if a DEBUG_EXPR_DECL can't be reused.  */
+	      for (lim = 32;
+		   !gsi_end_p (gsi) && lim > 0;
+		   gsi_next (&gsi), lim--)
+		{
+		  gimple gstmt = gsi_stmt (gsi);
+		  if (!gimple_debug_source_bind_p (gstmt))
+		    break;
+		  if (gimple_debug_source_bind_get_value (gstmt) == var)
+		    {
+		      def = gimple_debug_source_bind_get_var (gstmt);
+		      if (TREE_CODE (def) == DEBUG_EXPR_DECL)
+			break;
+		      else
+			def = NULL_TREE;
+		    }
+		}
+	      /* If not, add a new source bind stmt.  */
+	      if (def == NULL_TREE)
+		{
+		  gimple def_temp;
+		  def = make_node (DEBUG_EXPR_DECL);
+		  def_temp = gimple_build_debug_source_bind (def, var, NULL);
+		  DECL_ARTIFICIAL (def) = 1;
+		  TREE_TYPE (def) = TREE_TYPE (var);
+		  DECL_MODE (def) = DECL_MODE (var);
+		  gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
+		  gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
+		}
+	      update = true;
+	    }
+	}
+      else
+	def = get_current_def (var);
+      if (def == NULL)
+	{
+	  gimple_debug_bind_reset_value (stmt);
+	  update_stmt (stmt);
+	  return;
+	}
+      SET_USE (use_p, def);
+    }
+  if (update)
+    update_stmt (stmt);
+}
+
 /* SSA Rewriting Step 2.  Rewrite every variable used in each statement in
    the block with its immediate reaching definitions.  Update the current
    definition of a variable when a new real or virtual definition is found.  */
@@ -1306,12 +1383,17 @@ rewrite_stmt (gimple_stmt_iterator si)
 
   /* Step 1.  Rewrite USES in the statement.  */
   if (rewrite_uses_p (stmt))
-    FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
-      {
-	tree var = USE_FROM_PTR (use_p);
-	gcc_assert (DECL_P (var));
-	SET_USE (use_p, get_reaching_def (var));
-      }
+    {
+      if (is_gimple_debug (stmt))
+	rewrite_debug_stmt_uses (stmt);
+      else
+	FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+	  {
+	    tree var = USE_FROM_PTR (use_p);
+	    gcc_assert (DECL_P (var));
+	    SET_USE (use_p, get_reaching_def (var));
+	  }
+    }
 
   /* Step 2.  Register the statement's DEF operands.  */
   if (register_defs_p (stmt))