re PR debug/54519 (Debug info quality regression due to (pointless) partial inlining)

	PR debug/54519
	* ipa-split.c (split_function): Add debug args and
	debug source and normal stmts for args_to_skip which are
	gimple regs.
	* tree-inline.c (copy_debug_stmt): When inlining, adjust
	source debug bind stmts to debug binds of corresponding
	DEBUG_EXPR_DECL.

	* gcc.dg/guality/pr54519-1.c: New test.
	* gcc.dg/guality/pr54519-2.c: New test.
	* gcc.dg/guality/pr54519-3.c: New test.
	* gcc.dg/guality/pr54519-4.c: New test.
	* gcc.dg/guality/pr54519-5.c: New test.
	* gcc.dg/guality/pr54519-6.c: New test.

From-SVN: r192139

1 files changed, 78 insertions, 0 deletions

diff --git a/gcc/ipa-split.c b/gcc/ipa-split.c
index e1d1c49..6750c11 100644
--- a/gcc/ipa-split.c
+++ b/gcc/ipa-split.c
@@ -1059,6 +1059,7 @@ split_function (struct split_point *split_point)
   gimple last_stmt = NULL;
   unsigned int i;
   tree arg, ddef;
+  VEC(tree, gc) **debug_args = NULL;
 
   if (dump_file)
     {
@@ -1232,6 +1233,83 @@ split_function (struct split_point *split_point)
   gimple_set_block (call, DECL_INITIAL (current_function_decl));
   VEC_free (tree, heap, args_to_pass);
 
+  /* For optimized away parameters, add on the caller side
+     before the call
+     DEBUG D#X => parm_Y(D)
+     stmts and associate D#X with parm in decl_debug_args_lookup
+     vector to say for debug info that if parameter parm had been passed,
+     it would have value parm_Y(D).  */
+  if (args_to_skip)
+    for (parm = DECL_ARGUMENTS (current_function_decl), num = 0;
+	 parm; parm = DECL_CHAIN (parm), num++)
+      if (bitmap_bit_p (args_to_skip, num)
+	  && is_gimple_reg (parm))
+	{
+	  tree ddecl;
+	  gimple def_temp;
+
+	  /* This needs to be done even without MAY_HAVE_DEBUG_STMTS,
+	     otherwise if it didn't exist before, we'd end up with
+	     different SSA_NAME_VERSIONs between -g and -g0.  */
+	  arg = get_or_create_ssa_default_def (cfun, parm);
+	  if (!MAY_HAVE_DEBUG_STMTS)
+	    continue;
+
+	  if (debug_args == NULL)
+	    debug_args = decl_debug_args_insert (node->symbol.decl);
+	  ddecl = make_node (DEBUG_EXPR_DECL);
+	  DECL_ARTIFICIAL (ddecl) = 1;
+	  TREE_TYPE (ddecl) = TREE_TYPE (parm);
+	  DECL_MODE (ddecl) = DECL_MODE (parm);
+	  VEC_safe_push (tree, gc, *debug_args, DECL_ORIGIN (parm));
+	  VEC_safe_push (tree, gc, *debug_args, ddecl);
+	  def_temp = gimple_build_debug_bind (ddecl, unshare_expr (arg),
+					      call);
+	  gsi_insert_after (&gsi, def_temp, GSI_NEW_STMT);
+	}
+  /* And on the callee side, add
+     DEBUG D#Y s=> parm
+     DEBUG var => D#Y
+     stmts to the first bb where var is a VAR_DECL created for the
+     optimized away parameter in DECL_INITIAL block.  This hints
+     in the debug info that var (whole DECL_ORIGIN is the parm PARM_DECL)
+     is optimized away, but could be looked up at the call site
+     as value of D#X there.  */
+  if (debug_args != NULL)
+    {
+      unsigned int i;
+      tree var, vexpr;
+      gimple_stmt_iterator cgsi;
+      gimple def_temp;
+
+      push_cfun (DECL_STRUCT_FUNCTION (node->symbol.decl));
+      var = BLOCK_VARS (DECL_INITIAL (node->symbol.decl));
+      i = VEC_length (tree, *debug_args);
+      cgsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
+      do
+	{
+	  i -= 2;
+	  while (var != NULL_TREE
+		 && DECL_ABSTRACT_ORIGIN (var)
+		    != VEC_index (tree, *debug_args, i))
+	    var = TREE_CHAIN (var);
+	  if (var == NULL_TREE)
+	    break;
+	  vexpr = make_node (DEBUG_EXPR_DECL);
+	  parm = VEC_index (tree, *debug_args, i);
+	  DECL_ARTIFICIAL (vexpr) = 1;
+	  TREE_TYPE (vexpr) = TREE_TYPE (parm);
+	  DECL_MODE (vexpr) = DECL_MODE (parm);
+	  def_temp = gimple_build_debug_source_bind (vexpr, parm,
+						     NULL);
+	  gsi_insert_before (&cgsi, def_temp, GSI_SAME_STMT);
+	  def_temp = gimple_build_debug_bind (var, vexpr, NULL);
+	  gsi_insert_before (&cgsi, def_temp, GSI_SAME_STMT);
+	}
+      while (i);
+      pop_cfun ();
+    }
+
   /* We avoid address being taken on any variable used by split part,
      so return slot optimization is always possible.  Moreover this is
      required to make DECL_BY_REFERENCE work.  */