dwarf2cfi.c (struct dw_trace_info): Add args_size_defined_for_eh.

	* dwarf2cfi.c (struct dw_trace_info): Add args_size_defined_for_eh.
	(notice_args_size): Set it in the current trace if no insn that can
	throw internally has been seen yet.
	(connect_traces): When connecting args_size between traces, allow the
	incoming values not to match if there is an insn setting it before the
	first insn that can throw internally; in that case, force the creation
	of a CFI note on this latter insn.

From-SVN: r265142

gcc/ChangeLog

+2018-10-13  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* dwarf2cfi.c (struct dw_trace_info): Add args_size_defined_for_eh.
+	(notice_args_size): Set it in the current trace if no insn that can
+	throw internally has been seen yet.
+	(connect_traces): When connecting args_size between traces, allow the
+	incoming values not to match if there is an insn setting it before the
+	first insn that can throw internally; in that case, force the creation
+	of a CFI note on this latter insn.
+
 2018-10-13  Jonathan Wakely  <jwakely@redhat.com>
 
 	* opt-problem.h (opt_wrapper): Use template-argument-list when naming

gcc/dwarf2cfi.c

@@ -147,6 +147,9 @@ struct dw_trace_info
 
   /* True if we've seen different values incoming to beg_true_args_size.  */
   bool args_size_undefined;
+
+  /* True if we've seen an insn with a REG_ARGS_SIZE note before EH_HEAD.  */
+  bool args_size_defined_for_eh;
 };
 
 
@@ -942,6 +945,9 @@ notice_args_size (rtx_insn *insn)
   if (note == NULL)
     return;
 
+  if (!cur_trace->eh_head)
+    cur_trace->args_size_defined_for_eh = true;
+
   args_size = get_args_size (note);
   delta = args_size - cur_trace->end_true_args_size;
   if (known_eq (delta, 0))
@@ -2820,11 +2826,17 @@ connect_traces (void)
 
 	  if (ti->switch_sections)
 	    prev_args_size = 0;
+
 	  if (ti->eh_head == NULL)
 	    continue;
-	  gcc_assert (!ti->args_size_undefined);
 
-	  if (maybe_ne (ti->beg_delay_args_size, prev_args_size))
+	  /* We require either the incoming args_size values to match or the
+	     presence of an insn setting it before the first EH insn.  */
+	  gcc_assert (!ti->args_size_undefined || ti->args_size_defined_for_eh);
+
+	  /* In the latter case, we force the creation of a CFI note.  */
+	  if (ti->args_size_undefined
+	      || maybe_ne (ti->beg_delay_args_size, prev_args_size))
 	    {
 	      /* ??? Search back to previous CFI note.  */
 	      add_cfi_insn = PREV_INSN (ti->eh_head);