Fix FDE labels for Darwin

gcc/

	PR bootstrap/81033
	PR target/81733
	PR target/52795
	* gcc/dwarf2out.c (FUNC_SECOND_SECT_LABEL): New.
	(dwarf2out_switch_text_section): Generate a local label for the second
	function sub-section and apply it as the second FDE start label.
	* gcc/final.c (final_scan_insn_1): Emit second FDE label after the second
	sub-section start.

From-SVN: r263763

gcc/ChangeLog

+2018-08-22  Iain Sandoe  <iain@sandoe.co.uk>
+
+	PR bootstrap/81033
+	PR target/81733
+	PR target/52795
+	* gcc/dwarf2out.c (FUNC_SECOND_SECT_LABEL): New.
+	(dwarf2out_switch_text_section): Generate a local label for the second
+	function sub-section and apply it as the second FDE start label.
+	* gcc/final.c (final_scan_insn_1): Emit second FDE label after the second
+	sub-section start.
+
 2018-08-22  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/86988

gcc/dwarf2out.c

@@ -298,6 +298,10 @@ static unsigned int rnglist_idx;
 #define FUNC_BEGIN_LABEL	"LFB"
 #endif
 
+#ifndef FUNC_SECOND_SECT_LABEL
+#define FUNC_SECOND_SECT_LABEL	"LFSB"
+#endif
+
 #ifndef FUNC_END_LABEL
 #define FUNC_END_LABEL		"LFE"
 #endif
@@ -1213,21 +1217,24 @@ static void set_cur_line_info_table (section *);
 void
 dwarf2out_switch_text_section (void)
 {
+  char label[MAX_ARTIFICIAL_LABEL_BYTES];
   section *sect;
   dw_fde_ref fde = cfun->fde;
 
   gcc_assert (cfun && fde && fde->dw_fde_second_begin == NULL);
 
+  ASM_GENERATE_INTERNAL_LABEL (label, FUNC_SECOND_SECT_LABEL,
+			       current_function_funcdef_no);
+
+  fde->dw_fde_second_begin = ggc_strdup (label);
   if (!in_cold_section_p)
     {
       fde->dw_fde_end = crtl->subsections.cold_section_end_label;
-      fde->dw_fde_second_begin = crtl->subsections.hot_section_label;
       fde->dw_fde_second_end = crtl->subsections.hot_section_end_label;
     }
   else
     {
       fde->dw_fde_end = crtl->subsections.hot_section_end_label;
-      fde->dw_fde_second_begin = crtl->subsections.cold_section_label;
       fde->dw_fde_second_end = crtl->subsections.cold_section_end_label;
     }
   have_multiple_function_sections = true;

gcc/final.c

@@ -2232,6 +2232,9 @@ final_scan_insn_1 (rtx_insn *insn, FILE *file, int optimize_p ATTRIBUTE_UNUSED,
 	      ASM_OUTPUT_LABEL (asm_out_file,
 				IDENTIFIER_POINTER (cold_function_name));
 #endif
+	      if (dwarf2out_do_frame ()
+	          && cfun->fde->dw_fde_second_begin != NULL)
+		ASM_OUTPUT_LABEL (asm_out_file, cfun->fde->dw_fde_second_begin);
 	    }
 	  break;