Hi!
The GDB folks expressed interest in handling column information in
debug info, apparently clang emits it, but gcc does not.
I know we are late in the release cycle, so I'm not suggesting to
turn this on by default, but the following patch at least allows
users to request it through -gcolumn-info, so that GDB can be adjusted
to consume it and later on (GCC 8 or 9) we could perhaps switch the
default.
This patch handles just emitting DW_AT_decl_column and DW_AT_call_column
if requested (-gcolumn-info) and non-zero (i.e. the middle-end knows the
columns).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2017-02-17 Jakub Jelinek <ja...@redhat.com>
* common.opt (gno-column-info, gcolumn-info): New options.
* dwarf2out.c (dwarf2_lineno_debug_hooks): Formatting fix.
(check_die): Also test for multiple DW_AT_decl_column attributes.
(add_src_coords_attributes, dwarf2out_imported_module_or_decl_1): Add
DW_AT_decl_column if requested.
(gen_subprogram_die): Compare and/or add also DW_AT_decl_column
if requested.
(gen_variable_die): Likewise.
(add_call_src_coords_attributes): Add DW_AT_call_column if requested.
* doc/invoke.texi (-gcolumn-info, -gno-column-info): Document.
--- gcc/common.opt.jj 2017-02-01 16:41:45.000000000 +0100
+++ gcc/common.opt 2017-02-17 11:47:14.233098170 +0100
@@ -2805,6 +2805,14 @@ gcoff
Common Driver JoinedOrMissing Negative(gdwarf)
Generate debug information in COFF format.
+gno-column-info
+Common Driver RejectNegative Var(debug_column_info,0) Init(0)
+Don't record DW_AT_decl_column and DW_AT_call_column in DWARF.
+
+gcolumn-info
+Common Driver RejectNegative Var(debug_column_info,1)
+Record DW_AT_decl_column and DW_AT_call_column in DWARF.
+
gdwarf
Common Driver JoinedOrMissing Negative(gdwarf-)
Generate debug information in default version of DWARF format.
--- gcc/dwarf2out.c.jj 2017-02-09 23:01:46.000000000 +0100
+++ gcc/dwarf2out.c 2017-02-17 11:56:13.471834354 +0100
@@ -2732,7 +2732,7 @@ const struct gcc_debug_hooks dwarf2_line
debug_nothing_int_int, /* begin_block */
debug_nothing_int_int, /* end_block */
debug_true_const_tree, /* ignore_block */
- dwarf2out_source_line, /* source_line */
+ dwarf2out_source_line, /* source_line */
debug_nothing_int_charstar, /* begin_prologue */
debug_nothing_int_charstar, /* end_prologue */
debug_nothing_int_charstar, /* begin_epilogue */
@@ -6109,7 +6109,7 @@ check_die (dw_die_ref die)
dw_attr_node *a;
bool inline_found = false;
int n_location = 0, n_low_pc = 0, n_high_pc = 0, n_artificial = 0;
- int n_decl_line = 0, n_decl_file = 0;
+ int n_decl_line = 0, n_decl_column = 0, n_decl_file = 0;
FOR_EACH_VEC_SAFE_ELT (die->die_attr, ix, a)
{
switch (a->dw_attr)
@@ -6130,6 +6130,9 @@ check_die (dw_die_ref die)
case DW_AT_artificial:
++n_artificial;
break;
+ case DW_AT_decl_column:
+ ++n_decl_column;
+ break;
case DW_AT_decl_line:
++n_decl_line;
break;
@@ -6141,7 +6144,7 @@ check_die (dw_die_ref die)
}
}
if (n_location > 1 || n_low_pc > 1 || n_high_pc > 1 || n_artificial > 1
- || n_decl_line > 1 || n_decl_file > 1)
+ || n_decl_column > 1 || n_decl_line > 1 || n_decl_file > 1)
{
fprintf (stderr, "Duplicate attributes in DIE:\n");
debug_dwarf_die (die);
@@ -20190,6 +20193,8 @@ add_src_coords_attributes (dw_die_ref di
s = expand_location (DECL_SOURCE_LOCATION (decl));
add_AT_file (die, DW_AT_decl_file, lookup_filename (s.file));
add_AT_unsigned (die, DW_AT_decl_line, s.line);
+ if (debug_column_info && s.column)
+ add_AT_unsigned (die, DW_AT_decl_column, s.column);
}
/* Add DW_AT_{,MIPS_}linkage_name attribute for the given decl. */
@@ -21936,7 +21941,11 @@ gen_subprogram_die (tree decl, dw_die_re
&& (DECL_ARTIFICIAL (decl)
|| (get_AT_file (old_die, DW_AT_decl_file) == file_index
&& (get_AT_unsigned (old_die, DW_AT_decl_line)
- == (unsigned) s.line))))
+ == (unsigned) s.line)
+ && (!debug_column_info
+ || s.column == 0
+ || (get_AT_unsigned (old_die, DW_AT_decl_column)
+ == (unsigned) s.column)))))
{
subr_die = old_die;
@@ -21963,10 +21972,15 @@ gen_subprogram_die (tree decl, dw_die_re
add_AT_file (subr_die, DW_AT_decl_file, file_index);
if (get_AT_unsigned (old_die, DW_AT_decl_line) != (unsigned) s.line)
add_AT_unsigned (subr_die, DW_AT_decl_line, s.line);
+ if (debug_column_info
+ && s.column
+ && (get_AT_unsigned (old_die, DW_AT_decl_column)
+ != (unsigned) s.column))
+ add_AT_unsigned (subr_die, DW_AT_decl_column, s.column);
/* If the prototype had an 'auto' or 'decltype(auto)' return type,
emit the real type on the definition die. */
- if (is_cxx() && debug_info_level > DINFO_LEVEL_TERSE)
+ if (is_cxx () && debug_info_level > DINFO_LEVEL_TERSE)
{
dw_die_ref die = get_AT_ref (old_die, DW_AT_type);
if (die == auto_die || die == decltype_auto_die)
@@ -22838,6 +22852,12 @@ gen_variable_die (tree decl, tree origin
if (get_AT_unsigned (old_die, DW_AT_decl_line) != (unsigned) s.line)
add_AT_unsigned (var_die, DW_AT_decl_line, s.line);
+ if (debug_column_info
+ && s.column
+ && (get_AT_unsigned (old_die, DW_AT_decl_column)
+ != (unsigned) s.column))
+ add_AT_unsigned (var_die, DW_AT_decl_column, s.column);
+
if (old_die->die_tag == DW_TAG_member)
add_linkage_name (var_die, decl);
}
@@ -23011,6 +23031,8 @@ add_call_src_coords_attributes (tree stm
{
add_AT_file (die, DW_AT_call_file, lookup_filename (s.file));
add_AT_unsigned (die, DW_AT_call_line, s.line);
+ if (debug_column_info && s.column)
+ add_AT_unsigned (die, DW_AT_call_column, s.column);
}
}
@@ -25547,6 +25569,8 @@ dwarf2out_imported_module_or_decl_1 (tre
add_AT_file (imported_die, DW_AT_decl_file, lookup_filename (xloc.file));
add_AT_unsigned (imported_die, DW_AT_decl_line, xloc.line);
+ if (debug_column_info && xloc.column)
+ add_AT_unsigned (imported_die, DW_AT_decl_column, xloc.column);
if (name)
add_AT_string (imported_die, DW_AT_name,
IDENTIFIER_POINTER (name));
@@ -27959,7 +27983,9 @@ move_linkage_attr (dw_die_ref die)
{
dw_attr_node *prev = &(*die->die_attr)[ix - 1];
- if (prev->dw_attr == DW_AT_decl_line || prev->dw_attr == DW_AT_name)
+ if (prev->dw_attr == DW_AT_decl_line
+ || prev->dw_attr == DW_AT_decl_column
+ || prev->dw_attr == DW_AT_name)
break;
}
--- gcc/doc/invoke.texi.jj 2017-02-17 11:31:38.000000000 +0100
+++ gcc/doc/invoke.texi 2017-02-17 12:10:46.805110128 +0100
@@ -338,6 +338,7 @@ Objective-C and Objective-C++ Dialects}.
@gccoptlist{-g -g@var{level} -gcoff -gdwarf -gdwarf-@var{version} @gol
-ggdb -grecord-gcc-switches -gno-record-gcc-switches @gol
-gstabs -gstabs+ -gstrict-dwarf -gno-strict-dwarf @gol
+-gcolumn-info -gno-column-info @gol
-gvms -gxcoff -gxcoff+ -gz@r{[}=@var{type}@r{]} @gol
-fdebug-prefix-map=@var{old}=@var{new} -fdebug-types-section @gol
-feliminate-dwarf2-dups -fno-eliminate-unused-debug-types @gol
@@ -6822,6 +6823,14 @@ DWARF extensions from later standard ver
Allow using extensions of later DWARF standard version than selected with
@option{-gdwarf-@var{version}}.
+@item -gcolumn-info
+@item -gno-column-info
+@opindex gcolumn-info
+@opindex gno-column-info
+Emit location column information into DWARF debugging information, rather
+than just file and line.
+This option is disabled by default.
+
@item -gz@r{[}=@var{type}@r{]}
@opindex gz
Produce compressed debug sections in DWARF format, if that is supported.
Jakub
