On Tue, Jul 21, 2020 at 11:14 AM Jojo <jiejie_r...@c-sky.com> wrote:
>
> gcc/ChangeLog:
>
> * genemit.c (main): Print 'split line'.
> * Makefile.in (insn-emit.c): Define split count and file
>
Thanks for working one this, following comments are based on the
assumption that the approach is feasible after your investigation.
It's great to accelerate compilation time, do you have any number
showing how much this can achieve, on a typical machine with
reasonable parallelism?
> ---
> gcc/Makefile.in | 10 ++++++
> gcc/genemit.c | 86 +++++++++++++++++++++++++++----------------------
> 2 files changed, 58 insertions(+), 38 deletions(-)
>
> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> index 2ba76656dbf..f805050a119 100644
> --- a/gcc/Makefile.in
> +++ b/gcc/Makefile.in
> @@ -1253,6 +1253,13 @@ ANALYZER_OBJS = \
> # We put the *-match.o and insn-*.o files first so that a parallel make
> # will build them sooner, because they are large and otherwise tend to be
> # the last objects to finish building.
> +
> +insn-generated-split-num = 15
Hardcode number 15 looks strange here, how shall we know it's enough?
Or one step further, can we use some kind of general match "*" for
writing make rules here?
> +
> +insn-emit-split-c = $(foreach o, $(shell for i in
> {1..$(insn-generated-split-num)}; do echo $$i; done), insn-emit$(o).c)
> +insn-emit-split-obj = $(patsubst %.c,%.o, $(insn-emit-split-c))
> +$(insn-emit-split-c): insn-emit.c
> +
> OBJS = \
> gimple-match.o \
> generic-match.o \
> @@ -1260,6 +1267,7 @@ OBJS = \
> insn-automata.o \
> insn-dfatab.o \
> insn-emit.o \
> + $(insn-emit-split-obj) \
> insn-extract.o \
> insn-latencytab.o \
> insn-modes.o \
> @@ -2367,6 +2375,8 @@ $(simple_generated_c:insn-%.c=s-%): s-%:
> build/gen%$(build_exeext)
> $(RUN_GEN) build/gen$*$(build_exeext) $(md_file) \
> $(filter insn-conditions.md,$^) > tmp-$*.c
> $(SHELL) $(srcdir)/../move-if-change tmp-$*.c insn-$*.c
> + -csplit insn-$*.c /i\ am\ split\ line/ -k -s
> {$(insn-generated-split-num)} -f insn-$* -b "%d.c"
> + -( [ ! -s insn-$*0.c ] && for i in {1..$(insn-generated-split-num)};
> do touch insn-$*$$i.c; done && echo "" > insn-$*.c)
Not sure if this is the first time that csplit/coreutils is used,
shall we mention it here
https://gcc.gnu.org/install/prerequisites.html, even check it in
configure?
> $(STAMP) s-$*
>
> # gencheck doesn't read the machine description, and the file produced
> diff --git a/gcc/genemit.c b/gcc/genemit.c
> index 84d07d388ee..fd60cdeeb96 100644
> --- a/gcc/genemit.c
> +++ b/gcc/genemit.c
> @@ -847,6 +847,45 @@ handle_overloaded_gen (overloaded_name *oname)
> }
> }
>
> +#define printf_include() \
> + printf ("/* Generated automatically by the program `genemit'\n\
> +from the machine description file `md'. */\n\n"); \
> + printf ("#define IN_TARGET_CODE 1\n"); \
> + printf ("#include \"config.h\"\n"); \
> + printf ("#include \"system.h\"\n"); \
> + printf ("#include \"coretypes.h\"\n"); \
> + printf ("#include \"backend.h\"\n"); \
> + printf ("#include \"predict.h\"\n"); \
> + printf ("#include \"tree.h\"\n"); \
> + printf ("#include \"rtl.h\"\n"); \
> + printf ("#include \"alias.h\"\n"); \
> + printf ("#include \"varasm.h\"\n"); \
> + printf ("#include \"stor-layout.h\"\n"); \
> + printf ("#include \"calls.h\"\n"); \
> + printf ("#include \"memmodel.h\"\n"); \
> + printf ("#include \"tm_p.h\"\n"); \
> + printf ("#include \"flags.h\"\n"); \
> + printf ("#include \"insn-config.h\"\n"); \
> + printf ("#include \"expmed.h\"\n"); \
> + printf ("#include \"dojump.h\"\n"); \
> + printf ("#include \"explow.h\"\n"); \
> + printf ("#include \"emit-rtl.h\"\n"); \
> + printf ("#include \"stmt.h\"\n"); \
> + printf ("#include \"expr.h\"\n"); \
> + printf ("#include \"insn-codes.h\"\n"); \
> + printf ("#include \"optabs.h\"\n"); \
> + printf ("#include \"dfp.h\"\n"); \
> + printf ("#include \"output.h\"\n"); \
> + printf ("#include \"recog.h\"\n"); \
> + printf ("#include \"df.h\"\n"); \
> + printf ("#include \"resource.h\"\n"); \
> + printf ("#include \"reload.h\"\n"); \
> + printf ("#include \"diagnostic-core.h\"\n"); \
> + printf ("#include \"regs.h\"\n"); \
> + printf ("#include \"tm-constrs.h\"\n"); \
> + printf ("#include \"ggc.h\"\n"); \
> + printf ("#include \"target.h\"\n\n"); \
Can you use do {} while(0) style for defining this code block macro?
The trailing '\' is also strange here.
> +
> int
> main (int argc, const char **argv)
> {
> @@ -862,49 +901,19 @@ main (int argc, const char **argv)
> /* Assign sequential codes to all entries in the machine description
> in parallel with the tables in insn-output.c. */
>
> - printf ("/* Generated automatically by the program `genemit'\n\
> -from the machine description file `md'. */\n\n");
> -
> - printf ("#define IN_TARGET_CODE 1\n");
> - printf ("#include \"config.h\"\n");
> - printf ("#include \"system.h\"\n");
> - printf ("#include \"coretypes.h\"\n");
> - printf ("#include \"backend.h\"\n");
> - printf ("#include \"predict.h\"\n");
> - printf ("#include \"tree.h\"\n");
> - printf ("#include \"rtl.h\"\n");
> - printf ("#include \"alias.h\"\n");
> - printf ("#include \"varasm.h\"\n");
> - printf ("#include \"stor-layout.h\"\n");
> - printf ("#include \"calls.h\"\n");
> - printf ("#include \"memmodel.h\"\n");
> - printf ("#include \"tm_p.h\"\n");
> - printf ("#include \"flags.h\"\n");
> - printf ("#include \"insn-config.h\"\n");
> - printf ("#include \"expmed.h\"\n");
> - printf ("#include \"dojump.h\"\n");
> - printf ("#include \"explow.h\"\n");
> - printf ("#include \"emit-rtl.h\"\n");
> - printf ("#include \"stmt.h\"\n");
> - printf ("#include \"expr.h\"\n");
> - printf ("#include \"insn-codes.h\"\n");
> - printf ("#include \"optabs.h\"\n");
> - printf ("#include \"dfp.h\"\n");
> - printf ("#include \"output.h\"\n");
> - printf ("#include \"recog.h\"\n");
> - printf ("#include \"df.h\"\n");
> - printf ("#include \"resource.h\"\n");
> - printf ("#include \"reload.h\"\n");
> - printf ("#include \"diagnostic-core.h\"\n");
> - printf ("#include \"regs.h\"\n");
> - printf ("#include \"tm-constrs.h\"\n");
> - printf ("#include \"ggc.h\"\n");
> - printf ("#include \"target.h\"\n\n");
> + long long read_count = 0;
>
> /* Read the machine description. */
>
> md_rtx_info info;
> while (read_md_rtx (&info))
> + {
> + if (!(read_count++ % 10000))
> + {
> + printf ("/* i am split line %d :) */\n\n", read_count);
I would prefer a better comment explaining this line is to split file
into separate compilation units for parallel compilation.
> + printf_include()
Together with above comment about macro, it's better to have a semicolon here?
Thanks,
bin
> + }
> +
> switch (GET_CODE (info.def))
> {
> case DEFINE_INSN:
> @@ -929,6 +938,7 @@ from the machine description file `md'. */\n\n");
> default:
> break;
> }
> + }
>
> /* Write out the routines to add CLOBBERs to a pattern and say whether they
> clobber a hard reg. */
> --
> 2.24.3 (Apple Git-128)
>
