Re: [PATCH] DWARF5 .debug_rnglists support

[Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>]

Hi Jakub,

> 2016-11-01  Jakub Jelinek  <jakub@redhat.com>
>
> 	* tree.h (BLOCK_IN_COLD_SECTION_P): Define.
> 	* final.c (final_scan_insn): Set BLOCK_IN_COLD_SECTION_P.
> 	* dwarf2out.c (rnglist_idx): New variable.
> 	(struct dw_ranges): Add label, idx and maybe_new_sec fields.
> 	(DEBUG_RNGLISTS_SECTION): Define.
> 	(ranges_base_label): New variable.
> 	(size_of_die) <case dw_val_class_range_list>: If using
> 	DW_FORM_rnglistx, count size of uleb128 of range list index.
> 	(value_format) <case dw_val_class_range_list>: For
> 	-gdwarf-5 -gsplit-dwarf return DW_FORM_rnglistx.
> 	(output_range_list_offset): Handle -gdwarf-5 .debug_rnglists
> 	offsets.  Multiply dwarf < 5 offsets by 2 * DWARF_ADDR_SIZE.
> 	(add_ranges_num): Remove useless prototype.  Don't multiply
> 	by 2 * DWARF2_ADDR_SIZE.  Add maybe_new_sec argument, adjust
> 	for new fields added to dw_ranges struct.
> 	(add_ranges): Add maybe_new_sec argument and pass it
> 	through to add_ranges_num.
> 	(note_rnglist_head): New function.
> 	(add_ranges_by_labels): Pass true as maybe_new_sec to
> 	add_ranges_num, call note_rnglist_head on the head of the list.
> 	(output_ranges): Add function comment.  Switch to
> 	.debug_ranges section here and emit .Ldebug_ranges0 label.
> 	(index_rnglists, output_rnglists): New functions.
> 	(gen_subprogram_die): Formatting fixes.
> 	(add_high_low_attributes): Don't divide offsets
> 	by 2 * DWARF2_ADDR_SIZE.  Call note_rnglist_head on the
> 	first list element or when pointing into the middle of
> 	a list.  Pass true as second argument to add_ranges on the
> 	first block fragment after cold/hot section switch.
> 	(init_sections_and_labels): For -gdwarf-5 use .debug_rnglists
> 	section instead of .debug_ranges.  Initialize
> 	ranges_base_label if -gdwarf-5 -gsplit-dwarf.
> 	(dwarf2out_finish): For -gdwarf-5 -gsplit-dwarf call
> 	index_rnglists and add DW_AT_rnglists_base attr.  Don't switch
> 	to dwarf_ranges_section here or emit .Ldebug_ranges0 label.
> 	Call output_rnglists for -gdwarf-5.
> 	(dwarf2out_c_finalize): Clear rnglist_idx.

this patch broke Solaris bootstrap with /bin/as:

/vol/gcc/src/hg/trunk/local/gcc/dwarf2out.c: In function 'void output_rnglists()':
/vol/gcc/src/hg/trunk/local/gcc/dwarf2out.c:11055:8: error: unused variable 'basebuf' [-Werror=unused-variable]
   char basebuf[MAX_ARTIFICIAL_LABEL_BYTES];
        ^~~~~~~
/vol/gcc/src/hg/trunk/local/gcc/dwarf2out.c:11088:16: error: unused variable 'len' [-Werror=unused-variable]
   unsigned int len = vec_safe_length (ranges_table);
                ^~~

Fixed as follows; will commit as obvious once i386-pc-solaris2.12 and
sparc-sun-solaris2.12 bootstrap have finished successfully.

	Rainer

-- 
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University


2016-11-01  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	* dwarf2out.c (output_rnglists): Wrap basebuf, len in
	HAVE_AS_LEB128.

# HG changeset patch
# Parent  82d985a9e114ce85dac367da31077070f40d7ab8
Fix dwarf2out.c non-leb128 bootstrap failure

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -11052,7 +11052,9 @@ output_rnglists (void)
   dw_ranges *r;
   char l1[MAX_ARTIFICIAL_LABEL_BYTES];
   char l2[MAX_ARTIFICIAL_LABEL_BYTES];
+#ifdef HAVE_AS_LEB128
   char basebuf[MAX_ARTIFICIAL_LABEL_BYTES];
+#endif
 
   switch_to_section (debug_ranges_section);
   ASM_OUTPUT_LABEL (asm_out_file, ranges_section_label);
@@ -11085,9 +11087,9 @@ output_rnglists (void)
 				ranges_base_label, NULL);
     }
 
-  unsigned int len = vec_safe_length (ranges_table);
   const char *lab = "";
 #ifdef HAVE_AS_LEB128
+  unsigned int len = vec_safe_length (ranges_table);
   const char *base = NULL;
 #endif
   FOR_EACH_VEC_SAFE_ELT (ranges_table, i, r)