Make GCC respect SOURCE_DATE_EPOCH in __DATE__ and __TIME__ macros. Patch adapted from upstream source repository: https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=e3e8c48c4a494d9da741c1c8ea6c4c0b7c4ff934 From e3e8c48c4a494d9da741c1c8ea6c4c0b7c4ff934 Mon Sep 17 00:00:00 2001 From: doko Date: Thu, 28 Apr 2016 09:12:05 +0000 Subject: [PATCH] gcc/c-family/ChangeLog: 2016-04-28 Eduard Sanou Matthias Klose * c-common.c (get_source_date_epoch): New function, gets the environment variable SOURCE_DATE_EPOCH and parses it as long long with error handling. * c-common.h (get_source_date_epoch): Prototype. * c-lex.c (c_lex_with_flags): set parse_in->source_date_epoch. gcc/ChangeLog: 2016-04-28 Eduard Sanou Matthias Klose * doc/cppenv.texi: Document SOURCE_DATE_EPOCH environment variable. libcpp/ChangeLog: 2016-04-28 Eduard Sanou Matthias Klose * include/cpplib.h (cpp_init_source_date_epoch): Prototype. * init.c (cpp_init_source_date_epoch): New function. * internal.h: Added source_date_epoch variable to struct cpp_reader to store a reproducible date. * macro.c (_cpp_builtin_macro_text): Set pfile->date timestamp from pfile->source_date_epoch instead of localtime if source_date_epoch is set, to be used for __DATE__ and __TIME__ macros to help reproducible builds. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@235550 138bc75d-0d04-0410-961f-82ee72b054a4 diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index 1bf5d080034..6f0898a38d7 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -12318,4 +12318,37 @@ pointer_to_zero_sized_aggr_p (tree t) return (TYPE_SIZE (t) && integer_zerop (TYPE_SIZE (t))); } +/* Read SOURCE_DATE_EPOCH from environment to have a deterministic + timestamp to replace embedded current dates to get reproducible + results. Returns -1 if SOURCE_DATE_EPOCH is not defined. */ +time_t +get_source_date_epoch () +{ + char *source_date_epoch; + long long epoch; + char *endptr; + + source_date_epoch = getenv ("SOURCE_DATE_EPOCH"); + if (!source_date_epoch) + return (time_t) -1; + + errno = 0; + epoch = strtoll (source_date_epoch, &endptr, 10); + if ((errno == ERANGE && (epoch == LLONG_MAX || epoch == LLONG_MIN)) + || (errno != 0 && epoch == 0)) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "strtoll: %s\n", xstrerror(errno)); + if (endptr == source_date_epoch) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "no digits were found: %s\n", endptr); + if (*endptr != '\0') + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "trailing garbage: %s\n", endptr); + if (epoch < 0) + fatal_error (UNKNOWN_LOCATION, "environment variable $SOURCE_DATE_EPOCH: " + "value must be nonnegative: %lld \n", epoch); + + return (time_t) epoch; +} + #include "gt-c-family-c-common.h" diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h index fdb227f85c3..ba0a5d7df50 100644 --- a/gcc/c-family/c-common.h +++ b/gcc/c-family/c-common.h @@ -1437,4 +1437,10 @@ extern bool contains_cilk_spawn_stmt (tree); extern tree cilk_for_number_of_iterations (tree); extern bool check_no_cilk (tree, const char *, const char *, location_t loc = UNKNOWN_LOCATION); + +/* Read SOURCE_DATE_EPOCH from environment to have a deterministic + timestamp to replace embedded current dates to get reproducible + results. Returns -1 if SOURCE_DATE_EPOCH is not defined. */ +extern time_t get_source_date_epoch (void); + #endif /* ! GCC_C_COMMON_H */ diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c index bb55be8063e..e68471b9d2b 100644 --- a/gcc/c-family/c-lex.c +++ b/gcc/c-family/c-lex.c @@ -402,6 +402,9 @@ c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags, enum cpp_ttype type; unsigned char add_flags = 0; enum overflow_type overflow = OT_NONE; + time_t source_date_epoch = get_source_date_epoch (); + + cpp_init_source_date_epoch (parse_in, source_date_epoch); timevar_push (TV_CPP); retry: diff --git a/gcc/doc/cppenv.texi b/gcc/doc/cppenv.texi index 100811dc637..3b5317beb53 100644 --- a/gcc/doc/cppenv.texi +++ b/gcc/doc/cppenv.texi @@ -79,4 +79,21 @@ main input file is omitted. @ifclear cppmanual @xref{Preprocessor Options}. @end ifclear + +@item SOURCE_DATE_EPOCH + +If this variable is set, its value specifies a UNIX timestamp to be +used in replacement of the current date and time in the @code{__DATE__} +and @code{__TIME__} macros, so that the embedded timestamps become +reproducible. + +The value of @env{SOURCE_DATE_EPOCH} must be a UNIX timestamp, +defined as the number of seconds (excluding leap seconds) since +01 Jan 1970 00:00:00 represented in ASCII, identical to the output of +@samp{@command{date +%s}}. + +The value should be a known timestamp such as the last modification +time of the source or package and it should be set by the build +process. + @end vtable diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h index 1b731d1a3ad..7a5481219be 100644 --- a/libcpp/include/cpplib.h +++ b/libcpp/include/cpplib.h @@ -775,6 +775,9 @@ extern void cpp_init_special_builtins (cpp_reader *); /* Set up built-ins like __FILE__. */ extern void cpp_init_builtins (cpp_reader *, int); +/* Initialize the source_date_epoch value. */ +extern void cpp_init_source_date_epoch (cpp_reader *, time_t); + /* This is called after options have been parsed, and partially processed. */ extern void cpp_post_options (cpp_reader *); diff --git a/libcpp/init.c b/libcpp/init.c index 45a4d13ffa3..a8d00f4628b 100644 --- a/libcpp/init.c +++ b/libcpp/init.c @@ -530,6 +530,13 @@ cpp_init_builtins (cpp_reader *pfile, int hosted) _cpp_define_builtin (pfile, "__OBJC__ 1"); } +/* Initialize the source_date_epoch value. */ +void +cpp_init_source_date_epoch (cpp_reader *pfile, time_t source_date_epoch) +{ + pfile->source_date_epoch = source_date_epoch; +} + /* Sanity-checks are dependent on command-line options, so it is called as a subroutine of cpp_read_main_file (). */ #if ENABLE_CHECKING diff --git a/libcpp/internal.h b/libcpp/internal.h index c2d08168945..8507eba1747 100644 --- a/libcpp/internal.h +++ b/libcpp/internal.h @@ -502,6 +502,10 @@ struct cpp_reader const unsigned char *date; const unsigned char *time; + /* Externally set timestamp to replace current date and time useful for + reproducibility. */ + time_t source_date_epoch; + /* EOF token, and a token forcing paste avoidance. */ cpp_token avoid_paste; cpp_token eof; diff --git a/libcpp/macro.c b/libcpp/macro.c index eb32a6f8c98..3f3b278e97d 100644 --- a/libcpp/macro.c +++ b/libcpp/macro.c @@ -350,13 +350,20 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node) time_t tt; struct tm *tb = NULL; - /* (time_t) -1 is a legitimate value for "number of seconds - since the Epoch", so we have to do a little dance to - distinguish that from a genuine error. */ - errno = 0; - tt = time(NULL); - if (tt != (time_t)-1 || errno == 0) - tb = localtime (&tt); + /* Set a reproducible timestamp for __DATE__ and __TIME__ macro + usage if SOURCE_DATE_EPOCH is defined. */ + if (pfile->source_date_epoch != (time_t) -1) + tb = gmtime (&pfile->source_date_epoch); + else + { + /* (time_t) -1 is a legitimate value for "number of seconds + since the Epoch", so we have to do a little dance to + distinguish that from a genuine error. */ + errno = 0; + tt = time (NULL); + if (tt != (time_t)-1 || errno == 0) + tb = localtime (&tt); + } if (tb) { -- 2.11.0