dwarf2out: Fix up split-dwarf .debug_macro handling [PR99319]

The -gsplit-dwarf changes came a few months after .debug_macro
and the r0-120109 changes just changed the 2nd operand of
DW_MACRO_GNU_{define,undef}_indirect from the usual .debug_str
section offset argument to leb128 index into .debug_str_offsets
without changing the opcodes.

DWARF5 standardized different opcodes for those, but GCC hasn't been changed
yet for that.
This patch starts using DW_MACRO_define_strx and DW_MACRO_undef_strx
instead of DW_MACRO_define_strp and DW_MACRO_undef_strp when -gsplit-dwarf
-gdwarf-5 -g3.  I'm not sure what to do if anything with the -gdwarf-4
-gsplit-dwarf -g3 -gno-strict-dwarf case, we've been emitting it that way
for 8 years and it is an extension, so presumably the consumers that cared
have already hacks to handle DW_MACRO_GNU_{define,undef}_indirect
differently in .debug_macro 4 sections depending on if it is
.debug_macro.dwo or .debug_macro.
Another change the patch does is that it will use
DW_MACRO_{define,undef}_str{p,x} even with -gdwarf-5 -gstrict-dwarf -g3,
for DWARF 4 we were doing that only for -gno-strict-dwarf as we've emitted
.debug_macro section only in that case.

2021-03-02  Jakub Jelinek  <jakub@redhat.com>

	PR debug/99319
	* dwarf2out.c (output_macinfo_op): Use DW_MACRO_*_str* even with
	-gdwarf-5 -gstrict-dwarf.  For -gsplit-dwarf -gdwarf-5 use
	DW_MACRO_*_strx instead of DW_MACRO_*_strp.  Handle
	DW_MACRO_define_strx and DW_MACRO_undef_strx.
	(save_macinfo_strings): Use DW_MACRO_*_str* even with
	-gdwarf-5 -gstrict-dwarf.  Handle DW_MACRO_define_strx and
	DW_MACRO_undef_strx.

1 files changed, 21 insertions, 8 deletions

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index d6ad40a..95306e6 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -28267,13 +28267,17 @@ output_macinfo_op (macinfo_entry *ref)
     case DW_MACINFO_define:
     case DW_MACINFO_undef:
       len = strlen (ref->info) + 1;
-      if (!dwarf_strict
+      if ((!dwarf_strict || dwarf_version >= 5)
 	  && len > (size_t) dwarf_offset_size
 	  && !DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET
 	  && (debug_str_section->common.flags & SECTION_MERGE) != 0)
 	{
-	  ref->code = ref->code == DW_MACINFO_define
-		      ? DW_MACRO_define_strp : DW_MACRO_undef_strp;
+	  if (dwarf_split_debug_info && dwarf_version >= 5)
+	    ref->code = ref->code == DW_MACINFO_define
+			? DW_MACRO_define_strx : DW_MACRO_undef_strx;
+	  else
+	    ref->code = ref->code == DW_MACINFO_define
+			? DW_MACRO_define_strp : DW_MACRO_undef_strp;
 	  output_macinfo_op (ref);
 	  return;
 	}
@@ -28285,7 +28289,18 @@ output_macinfo_op (macinfo_entry *ref)
       dw2_asm_output_nstring (ref->info, -1, "The macro");
       break;
     case DW_MACRO_define_strp:
+      dw2_asm_output_data (1, ref->code, "Define macro strp");
+      goto do_DW_MACRO_define_strpx;
     case DW_MACRO_undef_strp:
+      dw2_asm_output_data (1, ref->code, "Undefine macro strp");
+      goto do_DW_MACRO_define_strpx;
+    case DW_MACRO_define_strx:
+      dw2_asm_output_data (1, ref->code, "Define macro strx");
+      goto do_DW_MACRO_define_strpx;
+    case DW_MACRO_undef_strx:
+      dw2_asm_output_data (1, ref->code, "Undefine macro strx");
+      /* FALLTHRU */
+    do_DW_MACRO_define_strpx:
       /* NB: dwarf2out_finish performs:
 	   1. save_macinfo_strings
 	   2. hash table traverse of index_string
@@ -28302,10 +28317,6 @@ output_macinfo_op (macinfo_entry *ref)
       gcc_assert (node
 		  && (node->form == DW_FORM_strp
 		      || node->form == dwarf_FORM (DW_FORM_strx)));
-      dw2_asm_output_data (1, ref->code,
-			   ref->code == DW_MACRO_define_strp
-			   ? "Define macro strp"
-			   : "Undefine macro strp");
       dw2_asm_output_data_uleb128 (ref->lineno, "At line number %lu",
 				   (unsigned long) ref->lineno);
       if (node->form == DW_FORM_strp)
@@ -28475,7 +28486,7 @@ save_macinfo_strings (void)
           case DW_MACINFO_define:
           case DW_MACINFO_undef:
             len = strlen (ref->info) + 1;
-            if (!dwarf_strict
+	    if ((!dwarf_strict || dwarf_version >= 5)
                 && len > (unsigned) dwarf_offset_size
                 && !DWARF2_INDIRECT_STRING_SUPPORT_MISSING_ON_TARGET
                 && (debug_str_section->common.flags & SECTION_MERGE) != 0)
@@ -28489,6 +28500,8 @@ save_macinfo_strings (void)
 	    /* Fall through. */
 	  case DW_MACRO_define_strp:
 	  case DW_MACRO_undef_strp:
+	  case DW_MACRO_define_strx:
+	  case DW_MACRO_undef_strx:
             set_indirect_string (find_AT_string (ref->info));
             break;
           default: