On Mon, Jul 31, 2023 at 1:07 PM Andrzej Turko via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Currently fprintf calls logging to a dump file take line numbers
> in the match.pd file directly as arguments.
> When match.pd is edited, referenced code changes line numbers,
> which causes changes to many fprintf calls and, thus, to many
> (usually all) .cc files generated by genmatch. This forces make
> to (unnecessarily) rebuild many .o files.
>
> With this change those logging fprintf calls reference an array
> of line numbers, which is defined in one of the produced files.
> Thanks to this, when match.pd changes, it is enough to rebuild
> that single file and, of course, those actually affected by the
> change.
>
> Signed-off-by: Andrzej Turko <andrzej.tu...@gmail.com>
How does this affect the size of the executable? We are replacing
pushing a small immediate to the stack with an indexed load plus push.
Maybe further indirecting the whole dumping, passing an index of the
match and __FILE__/__LINE__ would help here, so instead of
if (UNLIKELY (debug_dump)) fprintf
(dump_file, "Matching expression %s:%d, %s:%d\n", "match.pd", 2522,
__FILE__, __LINE__);
we emit sth like
if (UNLIKELY (debug_dump)) dump_match (2522,
__FILE__, __LINE__);
with 2522 replaced by the ID? That would also get rid of the inline
varargs invocation which might help code size as well (on some targets).
Richard.
> gcc/ChangeLog:
>
> * genmatch.cc: Keep line numbers from match.pd in an array.
>
> Signed-off-by: Andrzej Turko <andrzej.tu...@gmail.com>
> ---
> gcc/genmatch.cc | 73 +++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 65 insertions(+), 8 deletions(-)
>
> diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
> index 1deca505603..0a480a140c9 100644
> --- a/gcc/genmatch.cc
> +++ b/gcc/genmatch.cc
> @@ -217,9 +217,48 @@ fp_decl_done (FILE *f, const char *trailer)
> fprintf (header_file, "%s;", trailer);
> }
>
> +/* Line numbers for use by indirect line directives. */
> +static vec<int> dbg_line_numbers;
> +
> +static void
> +write_header_declarations (bool gimple, FILE *f)
> +{
> + if (gimple)
> + fprintf (f, "\nextern int __gimple_dbg_line_numbers[];\n");
> + else
> + fprintf (f, "\nextern int __generic_dbg_line_numbers[];\n");
> +}
> +
> +static void
> +define_dbg_line_numbers (bool gimple, FILE *f)
> +{
> + if (gimple)
> + fprintf (f, "\nint __gimple_dbg_line_numbers[%d] = {",
> + dbg_line_numbers.length ());
> + else
> + fprintf (f, "\nint __generic_dbg_line_numbers[%d] = {",
> + dbg_line_numbers.length ());
> +
> + if (dbg_line_numbers.is_empty ())
> + {
> + fprintf (f, "};\n\n");
> + return;
> + }
> +
> + for (int i = 0; i < (int)dbg_line_numbers.length () - 1; i++)
> + {
> + if (i % 20 == 0)
> + fprintf (f, "\n\t");
> +
> + fprintf (f, "%d, ", dbg_line_numbers[i]);
> + }
> + fprintf (f, "%d\n};\n\n", dbg_line_numbers.last ());
> +}
> +
> static void
> output_line_directive (FILE *f, location_t location,
> - bool dumpfile = false, bool fnargs = false)
> + bool dumpfile = false, bool fnargs = false,
> + bool indirect_line_numbers = false, bool gimple = false)
> {
> const line_map_ordinary *map;
> linemap_resolve_location (line_table, location, LRK_SPELLING_LOCATION,
> &map);
> @@ -239,7 +278,20 @@ output_line_directive (FILE *f, location_t location,
> ++file;
>
> if (fnargs)
> - fprintf (f, "\"%s\", %d", file, loc.line);
> + {
> + if (indirect_line_numbers)
> + {
> + if (gimple)
> + fprintf (f, "\"%s\", __gimple_dbg_line_numbers[%d]",
> + file, dbg_line_numbers.length ());
> + else
> + fprintf (f, "\"%s\", __generic_dbg_line_numbers[%d]",
> + file, dbg_line_numbers.length ());
> + dbg_line_numbers.safe_push (loc.line);
> + }
> + else
> + fprintf (f, "\"%s\", %d", file, loc.line);
> + }
> else
> fprintf (f, "%s:%d", file, loc.line);
> }
> @@ -3378,7 +3430,8 @@ dt_operand::gen (FILE *f, int indent, bool gimple, int
> depth)
> /* Emit a fprintf to the debug file to the file F, with the INDENT from
> either the RESULT location or the S's match location if RESULT is null. */
> static void
> -emit_debug_printf (FILE *f, int indent, class simplify *s, operand *result)
> +emit_debug_printf (FILE *f, int indent, class simplify *s, operand *result,
> + bool gimple)
> {
> fprintf_indent (f, indent, "if (UNLIKELY (debug_dump)) "
> "fprintf (dump_file, \"%s ",
> @@ -3387,7 +3440,7 @@ emit_debug_printf (FILE *f, int indent, class simplify
> *s, operand *result)
> fprintf (f, "%%s:%%d, %%s:%%d\\n\", ");
> output_line_directive (f,
> result ? result->location : s->match->location, true,
> - true);
> + true, true, gimple);
> fprintf (f, ", __FILE__, __LINE__);\n");
> }
>
> @@ -3524,7 +3577,7 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> if (!result)
> {
> /* If there is no result then this is a predicate implementation. */
> - emit_debug_printf (f, indent, s, result);
> + emit_debug_printf (f, indent, s, result, gimple);
> fprintf_indent (f, indent, "return true;\n");
> }
> else if (gimple)
> @@ -3615,7 +3668,7 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> }
> else
> gcc_unreachable ();
> - emit_debug_printf (f, indent, s, result);
> + emit_debug_printf (f, indent, s, result, gimple);
> fprintf_indent (f, indent, "return true;\n");
> }
> else /* GENERIC */
> @@ -3670,7 +3723,7 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> }
> if (is_predicate)
> {
> - emit_debug_printf (f, indent, s, result);
> + emit_debug_printf (f, indent, s, result, gimple);
> fprintf_indent (f, indent, "return true;\n");
> }
> else
> @@ -3738,7 +3791,7 @@ dt_simplify::gen_1 (FILE *f, int indent, bool gimple,
> operand *result)
> i);
> }
> }
> - emit_debug_printf (f, indent, s, result);
> + emit_debug_printf (f, indent, s, result, gimple);
> fprintf_indent (f, indent, "return _r;\n");
> }
> }
> @@ -5447,6 +5500,7 @@ main (int argc, char **argv)
> parts.quick_push (stdout);
> write_header (stdout, s_include_file);
> write_header_includes (gimple, stdout);
> + write_header_declarations (gimple, stdout);
> }
> else
> {
> @@ -5460,6 +5514,7 @@ main (int argc, char **argv)
> fprintf (header_file, "#ifndef GCC_GIMPLE_MATCH_AUTO_H\n"
> "#define GCC_GIMPLE_MATCH_AUTO_H\n");
> write_header_includes (gimple, header_file);
> + write_header_declarations (gimple, header_file);
> }
>
> /* Go over all predicates defined with patterns and perform
> @@ -5502,6 +5557,8 @@ main (int argc, char **argv)
>
> dt.gen (parts, gimple);
>
> + define_dbg_line_numbers (gimple, choose_output (parts));
> +
> for (FILE *f : parts)
> {
> fprintf (f, "#pragma GCC diagnostic pop\n");
> --
> 2.34.1
>
