From faa91c472be8ffa3121c9db803d3e529d48e246a Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Sat, 7 Jan 2023 18:18:19 +0900 Subject: [PATCH] fixdep: avoid parsing the same file over again The dep files (*.d files) emitted by C compilers usually contain the deduplicated list of included files. One exceptional case is when a header is included by the -include command line option, and also by #include directive. For example, the top Makefile adds the command line option, "-include $(srctree)/include/linux/kconfig.h". You do not need to include in every source file. In fact, include/linux/kconfig.h is listed twice in many .*.cmd files due to include/linux/xarray.h having "#include ". I did not fix that since it is a small redundancy. However, this is more annoying for rustc. rustc emits the dependency for each emission type. For example, cmd_rustc_library emits dep-info, obj, and metadata. So, the emitted *.d file contains the dependency for those 3 targets, which makes fixdep parse the same file 3 times. $ grep rust/alloc/raw_vec.rs rust/.alloc.o.cmd rust/alloc/raw_vec.rs \ rust/alloc/raw_vec.rs \ rust/alloc/raw_vec.rs \ To skip the second parsing, this commit adds a hash table for parsed files, just like we did for CONFIG options. Signed-off-by: Masahiro Yamada Acked-by: Miguel Ojeda Tested-by: Miguel Ojeda Reviewed-by: Vincenzo Palazzo --- scripts/basic/fixdep.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c index 74f90a0..e22e689 100644 --- a/scripts/basic/fixdep.c +++ b/scripts/basic/fixdep.c @@ -113,7 +113,7 @@ struct item { }; #define HASHSZ 256 -static struct item *config_hashtab[HASHSZ]; +static struct item *config_hashtab[HASHSZ], *file_hashtab[HASHSZ]; static unsigned int strhash(const char *str, unsigned int sz) { @@ -365,6 +365,10 @@ static void parse_dep_file(char *p, const char *target) * name, which will be the original one, and ignore any * other source names, which will be intermediate * temporary files. + * + * rustc emits the same dependency list for each + * emission type. It is enough to list the source name + * just once. */ if (!saw_any_target) { saw_any_target = true; @@ -372,7 +376,8 @@ static void parse_dep_file(char *p, const char *target) printf("deps_%s := \\\n", target); need_parse = true; } - } else if (!is_ignored_file(p, q - p)) { + } else if (!is_ignored_file(p, q - p) && + !in_hashtable(p, q - p, file_hashtab)) { printf(" %s \\\n", p); need_parse = true; } -- 2.7.4