enable adjustment of return_pc debug attrs

This patch introduces infrastructure for targets to add an offset to
the label issued after the call_insn to set the call_return_pc
attribute.  This will be used on rs6000, that sometimes issues another
instruction after the call proper as part of a call insn.

for  gcc/ChangeLog

	* target.def (call_offset_return_label): New hook.
	* doc/tm.texi.in (TARGET_CALL_OFFSET_RETURN_LABEL): Add
	placeholder.
	* doc/tm.texi: Rebuild.
	* dwarf2out.cc (struct call_arg_loc_node): Record call_insn
	instead of call_arg_loc_note.
	(add_AT_lbl_id): Add optional offset argument.
	(gen_call_site_die): Compute and pass on a return pc offset.
	(gen_subprogram_die): Move call_arg_loc_note computation...
	(dwarf2out_var_location): ... from here.  Set call_insn.

diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index cd50078227d98b0ded003c49962d3b99e2b42fdb..8a7aa70d605bac27fd94bc37744ad61ae9faab6c 100644 (file)
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -5557,6 +5557,13 @@ except the last are treated as named.
 You need not define this hook if it always returns @code{false}.
 @end deftypefn
 
+@deftypefn {Target Hook} int TARGET_CALL_OFFSET_RETURN_LABEL (rtx_insn *@var{call_insn})
+While generating call-site debug info for a CALL insn, or a SEQUENCE
+insn starting with a CALL, this target hook is invoked to compute the
+offset to be added to the debug label emitted after the call to obtain
+the return address that should be recorded as the return PC.
+@end deftypefn
+
 @deftypefn {Target Hook} void TARGET_START_CALL_ARGS (cumulative_args_t @var{complete_args})
 This target hook is invoked while generating RTL for a function call,
 after the argument values have been computed, and after stack arguments

diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 058bd56487a9aa8aa71113fc6388bbe4ce7f99db..9e0830758aeea295673912eb5485e08c7a1a60ec 100644 (file)
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -3887,6 +3887,8 @@ These machine description macros help implement varargs:
 
 @hook TARGET_STRICT_ARGUMENT_NAMING
 
+@hook TARGET_CALL_OFFSET_RETURN_LABEL
+
 @hook TARGET_START_CALL_ARGS
 
 @hook TARGET_CALL_ARGS

diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 89efa5474d3ad9983ff17f2d903806aaa959b64b..f90f7b1cfef27a993a40c0c86fe9594b211ccd68 100644 (file)
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -3593,7 +3593,7 @@ typedef struct var_loc_list_def var_loc_list;
 
 /* Call argument location list.  */
 struct GTY ((chain_next ("%h.next"))) call_arg_loc_node {
-  rtx GTY (()) call_arg_loc_note;
+  rtx_insn * GTY (()) call_insn;
   const char * GTY (()) label;
   tree GTY (()) block;
   bool tail_call_p;
@@ -3777,7 +3777,8 @@ static void remove_addr_table_entry (addr_table_entry *);
 static void add_AT_addr (dw_die_ref, enum dwarf_attribute, rtx, bool);
 static inline rtx AT_addr (dw_attr_node *);
 static void add_AT_symview (dw_die_ref, enum dwarf_attribute, const char *);
-static void add_AT_lbl_id (dw_die_ref, enum dwarf_attribute, const char *);
+static void add_AT_lbl_id (dw_die_ref, enum dwarf_attribute, const char *,
+                          int = 0);
 static void add_AT_lineptr (dw_die_ref, enum dwarf_attribute, const char *);
 static void add_AT_macptr (dw_die_ref, enum dwarf_attribute, const char *);
 static void add_AT_range_list (dw_die_ref, enum dwarf_attribute,
@@ -5353,14 +5354,17 @@ add_AT_symview (dw_die_ref die, enum dwarf_attribute attr_kind,
 
 static inline void
 add_AT_lbl_id (dw_die_ref die, enum dwarf_attribute attr_kind,
-               const char *lbl_id)
+              const char *lbl_id, int offset)
 {
   dw_attr_node attr;
 
   attr.dw_attr = attr_kind;
   attr.dw_attr_val.val_class = dw_val_class_lbl_id;
   attr.dw_attr_val.val_entry = NULL;
-  attr.dw_attr_val.v.val_lbl_id = xstrdup (lbl_id);
+  if (!offset)
+    attr.dw_attr_val.v.val_lbl_id = xstrdup (lbl_id);
+  else
+    attr.dw_attr_val.v.val_lbl_id = xasprintf ("%s%+i", lbl_id, offset);
   if (dwarf_split_debug_info)
     attr.dw_attr_val.val_entry
         = add_addr_table_entry (attr.dw_attr_val.v.val_lbl_id,
@@ -23547,7 +23551,9 @@ gen_call_site_die (tree decl, dw_die_ref subr_die,
   if (stmt_die == NULL)
     stmt_die = subr_die;
   die = new_die (dwarf_TAG (DW_TAG_call_site), stmt_die, NULL_TREE);
-  add_AT_lbl_id (die, dwarf_AT (DW_AT_call_return_pc), ca_loc->label);
+  add_AT_lbl_id (die, dwarf_AT (DW_AT_call_return_pc),
+                ca_loc->label,
+                targetm.calls.call_offset_return_label (ca_loc->call_insn));
   if (ca_loc->tail_call_p)
     add_AT_flag (die, dwarf_AT (DW_AT_call_tail_call), 1);
   if (ca_loc->symbol_ref)
@@ -24234,11 +24240,14 @@ gen_subprogram_die (tree decl, dw_die_ref context_die)
            {
              dw_die_ref die = NULL;
              rtx tloc = NULL_RTX, tlocc = NULL_RTX;
+             rtx call_arg_loc_note
+               = find_reg_note (ca_loc->call_insn,
+                                REG_CALL_ARG_LOCATION, NULL_RTX);
              rtx arg, next_arg;
              tree arg_decl = NULL_TREE;
 
-             for (arg = (ca_loc->call_arg_loc_note != NULL_RTX
-                         ? XEXP (ca_loc->call_arg_loc_note, 0)
+             for (arg = (call_arg_loc_note != NULL_RTX
+                         ? XEXP (call_arg_loc_note, 0)
                          : NULL_RTX);
                   arg; arg = next_arg)
                {
@@ -28283,8 +28292,7 @@ create_label:
        = ggc_cleared_alloc<call_arg_loc_node> ();
       rtx_insn *prev = call_insn;
 
-      ca_loc->call_arg_loc_note
-       = find_reg_note (call_insn, REG_CALL_ARG_LOCATION, NULL_RTX);
+      ca_loc->call_insn = call_insn;
       ca_loc->next = NULL;
       ca_loc->label = last_label;
       gcc_assert (prev

diff --git a/gcc/target.def b/gcc/target.def
index c27df8095be159b402cdb916af9c84a84a556d77..70070caebc76832f5a2561dea8f937a69f925c7c 100644 (file)
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -4890,6 +4890,15 @@ Most ports do not need to implement anything for this hook.",
  void, (cumulative_args_t complete_args),
  hook_void_CUMULATIVE_ARGS)
 
+DEFHOOK
+(call_offset_return_label,
+ "While generating call-site debug info for a CALL insn, or a SEQUENCE\n\
+insn starting with a CALL, this target hook is invoked to compute the\n\
+offset to be added to the debug label emitted after the call to obtain\n\
+the return address that should be recorded as the return PC.",
+ int, (rtx_insn *call_insn),
+ hook_int_rtx_insn_0)
+
 DEFHOOK
 (push_argument,
  "This target hook returns @code{true} if push instructions will be\n\