re PR debug/43983 (var-tracking needlessly throws away location info for SRAed vars)

	PR debug/43983
	* var-tracking.c (track_expr_p): Allow tracking of variables optimized
	by SRA.
	* Makefile.in (dwarf2out.o): Depend on $(TREE_FLOW_H).
	* tree-sra.c (create_access_replacement): Call unshare_expr before
	passing expr to SET_DECL_DEBUG_EXPR, and remove any SSA_NAMEs from
	it.
	* dwarf2out.c: Include tree-flow.h.
	(struct var_loc_node): Rename var_loc_note field to loc, add comment.
	(size_of_loc_descr, output_loc_operands, output_loc_operands_raw):
	Handle DW_OP_bit_piece.
	(decl_piece_bitsize, decl_piece_varloc_ptr, decl_piece_node,
	construct_piece_list, adjust_piece_list): New functions.
	(add_var_loc_to_decl): Handle SRA optimized variables.
	Adjust for var_loc_note to loc field renaming.
	(dw_loc_list_1): For WANT_ADDRESS == 2 prefer DECL_MODE of decl
	in VAR_LOCATION note.
	(new_loc_descr_op_bit_piece): New function.
	(dw_sra_loc_expr): New function.
	(dw_loc_list): Use it.  Don't handle the last range after the
	loop, handle it inside of the loop.  Adjust for var_loc_note
	to loc field renaming.
	(add_location_or_const_value_attribute): Only special case
	single entry loc lists if loc is NOTE_P.  Adjust for
	var_loc_note to loc field renaming.
	(dwarf2out_var_location): Don't set newloc->var_loc_note
	and newloc->next here.

	* gcc.dg/guality/sra-1.c: New test.

From-SVN: r159357

gcc/ChangeLog

+2010-05-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/43983
+	* var-tracking.c (track_expr_p): Allow tracking of variables optimized
+	by SRA.
+	* Makefile.in (dwarf2out.o): Depend on $(TREE_FLOW_H).
+	* tree-sra.c (create_access_replacement): Call unshare_expr before
+	passing expr to SET_DECL_DEBUG_EXPR, and remove any SSA_NAMEs from
+	it.
+	* dwarf2out.c: Include tree-flow.h.
+	(struct var_loc_node): Rename var_loc_note field to loc, add comment.
+	(size_of_loc_descr, output_loc_operands, output_loc_operands_raw):
+	Handle DW_OP_bit_piece.
+	(decl_piece_bitsize, decl_piece_varloc_ptr, decl_piece_node,
+	construct_piece_list, adjust_piece_list): New functions.
+	(add_var_loc_to_decl): Handle SRA optimized variables.
+	Adjust for var_loc_note to loc field renaming.
+	(dw_loc_list_1): For WANT_ADDRESS == 2 prefer DECL_MODE of decl
+	in VAR_LOCATION note.
+	(new_loc_descr_op_bit_piece): New function.
+	(dw_sra_loc_expr): New function.
+	(dw_loc_list): Use it.  Don't handle the last range after the
+	loop, handle it inside of the loop.  Adjust for var_loc_note
+	to loc field renaming.
+	(add_location_or_const_value_attribute): Only special case
+	single entry loc lists if loc is NOTE_P.  Adjust for
+	var_loc_note to loc field renaming.
+	(dwarf2out_var_location): Don't set newloc->var_loc_note
+	and newloc->next here.
+
 2010-05-12  Jan Hubicka  <jh@suse.cz>
 
 	* cgraph.c (cgraph_mark_address_taken_node): No longer imply needed flag.

gcc/Makefile.in

@@ -2846,7 +2846,7 @@ dwarf2out.o : dwarf2out.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
    output.h $(DIAGNOSTIC_H) $(REAL_H) hard-reg-set.h $(REGS_H) $(EXPR_H) \
    libfuncs.h $(TOPLEV_H) dwarf2out.h reload.h $(GGC_H) $(EXCEPT_H) dwarf2asm.h \
    $(TM_P_H) langhooks.h $(HASHTAB_H) gt-dwarf2out.h $(TARGET_H) $(CGRAPH_H) \
-   $(MD5_H) $(INPUT_H) $(FUNCTION_H) $(GIMPLE_H) $(TREE_PASS_H)
+   $(MD5_H) $(INPUT_H) $(FUNCTION_H) $(GIMPLE_H) $(TREE_PASS_H) $(TREE_FLOW_H)
 dwarf2asm.o : dwarf2asm.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
    $(FLAGS_H) $(RTL_H) $(TREE_H) output.h dwarf2asm.h $(TM_P_H) $(GGC_H) \
    gt-dwarf2asm.h $(DWARF2_H) $(SPLAY_TREE_H) $(TARGET_H)

gcc/testsuite/ChangeLog

+2010-05-13  Jakub Jelinek  <jakub@redhat.com>
+
+	PR debug/43983
+	* gcc.dg/guality/sra-1.c: New test.
+
 2010-05-12  Jan Hubicka  <jh@suse.cz>
 
 	* tree-ssa/unreachable.c: New test.

gcc/testsuite/gcc.dg/guality/sra-1.c

+/* PR debug/43983 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+
+struct A { int i; int j; };
+struct B { int : 4; int i : 12; int j : 12; int : 4; };
+
+__attribute__((noinline)) void
+bar (int x)
+{
+  asm volatile ("" : : "r" (x) : "memory");
+}
+
+__attribute__((noinline)) int
+f1 (int k)
+{
+  struct A a = { 4, k + 6 };
+  asm ("" : "+r" (a.i));
+  a.j++;
+  bar (a.i);		/* { dg-final { gdb-test 20 "a.i" "4" } } */
+  bar (a.j);		/* { dg-final { gdb-test 20 "a.j" "14" } } */
+  return a.i + a.j;
+}
+
+__attribute__((noinline)) int
+f2 (int k)
+{
+  int a[2] = { 4, k + 6 };
+  asm ("" : "+r" (a[0]));
+  a[1]++;
+  bar (a[0]);		/* { dg-final { gdb-test 31 "a\[0\]" "4" } } */
+  bar (a[1]);		/* { dg-final { gdb-test 31 "a\[1\]" "14" } } */
+  return a[0] + a[1];
+}
+
+__attribute__((noinline)) int
+f3 (int k)
+{
+  struct B a = { 4, k + 6 };
+  asm ("" : "+r" (a.i));
+  a.j++;
+  bar (a.i);		/* { dg-final { gdb-test 42 "a.i" "4" } } */
+  bar (a.j);		/* { dg-final { gdb-test 42 "a.j" "14" } } */
+  return a.i + a.j;
+}
+
+int
+main (void)
+{
+  int k;
+  asm ("" : "=r" (k) : "0" (7));
+  f1 (k);
+  f2 (k);
+  f3 (k);
+  return 0;
+}

gcc/tree-sra.c

@@ -1609,11 +1609,38 @@ create_access_replacement (struct access *access)
       && !DECL_ARTIFICIAL (access->base))
     {
       char *pretty_name = make_fancy_name (access->expr);
+      tree debug_expr = unshare_expr (access->expr), d;
 
       DECL_NAME (repl) = get_identifier (pretty_name);
       obstack_free (&name_obstack, pretty_name);
 
-      SET_DECL_DEBUG_EXPR (repl, access->expr);
+      /* Get rid of any SSA_NAMEs embedded in debug_expr,
+	 as DECL_DEBUG_EXPR isn't considered when looking for still
+	 used SSA_NAMEs and thus they could be freed.  All debug info
+	 generation cares is whether something is constant or variable
+	 and that get_ref_base_and_extent works properly on the
+	 expression.  */
+      for (d = debug_expr; handled_component_p (d); d = TREE_OPERAND (d, 0))
+	switch (TREE_CODE (d))
+	  {
+	  case ARRAY_REF:
+	  case ARRAY_RANGE_REF:
+	    if (TREE_OPERAND (d, 1)
+		&& TREE_CODE (TREE_OPERAND (d, 1)) == SSA_NAME)
+	      TREE_OPERAND (d, 1) = SSA_NAME_VAR (TREE_OPERAND (d, 1));
+	    if (TREE_OPERAND (d, 3)
+		&& TREE_CODE (TREE_OPERAND (d, 3)) == SSA_NAME)
+	      TREE_OPERAND (d, 3) = SSA_NAME_VAR (TREE_OPERAND (d, 3));
+	    /* FALLTHRU */
+	  case COMPONENT_REF:
+	    if (TREE_OPERAND (d, 2)
+		&& TREE_CODE (TREE_OPERAND (d, 2)) == SSA_NAME)
+	      TREE_OPERAND (d, 2) = SSA_NAME_VAR (TREE_OPERAND (d, 2));
+	    break;
+	  default:
+	    break;
+	  }
+      SET_DECL_DEBUG_EXPR (repl, debug_expr);
       DECL_DEBUG_EXPR_IS_FROM (repl) = 1;
       TREE_NO_WARNING (repl) = TREE_NO_WARNING (access->base);
     }

gcc/var-tracking.c

@@ -4505,10 +4505,27 @@ track_expr_p (tree expr, bool need_rtl)
       realdecl = DECL_DEBUG_EXPR (realdecl);
       if (realdecl == NULL_TREE)
 	realdecl = expr;
-      /* ??? We don't yet know how to emit DW_OP_piece for variable
-	 that has been SRA'ed.  */
       else if (!DECL_P (realdecl))
-	return 0;
+	{
+	  if (handled_component_p (realdecl))
+	    {
+	      HOST_WIDE_INT bitsize, bitpos, maxsize;
+	      tree innerdecl
+		= get_ref_base_and_extent (realdecl, &bitpos, &bitsize,
+					   &maxsize);
+	      if (!DECL_P (innerdecl)
+		  || DECL_IGNORED_P (innerdecl)
+		  || TREE_STATIC (innerdecl)
+		  || bitsize <= 0
+		  || bitpos + bitsize > 256
+		  || bitsize != maxsize)
+		return 0;
+	      else
+		realdecl = expr;
+	    }
+	  else
+	    return 0;
+	}
     }
 
   /* Do not track EXPR if REALDECL it should be ignored for debugging