[Buildroot] [PATCH 02/15] gcc5: honor SOURCE_DATE_EPOCH
Jérôme Pouiller
jezz at sysmic.org
Thu Nov 17 10:00:26 UTC 2016
Support $SOURCE_DATE_EPOCH is necessary to create reproducible build.
Unfortunately, it is not yet widely available. This patch add support for
SOURCE_DATE_EPOCH to Buildroot internal toolchains based on gcc 5.
This work was sponsored by `BA Robotic Systems'.
Signed-off-by: Jérôme Pouiller <jezz at sysmic.org>
---
.../gcc/5.4.0/950-honor-SOURCE_DATE_EPOCH.patch | 213 +++++++++++++++++++++
1 file changed, 213 insertions(+)
create mode 100644 package/gcc/5.4.0/950-honor-SOURCE_DATE_EPOCH.patch
diff --git a/package/gcc/5.4.0/950-honor-SOURCE_DATE_EPOCH.patch b/package/gcc/5.4.0/950-honor-SOURCE_DATE_EPOCH.patch
new file mode 100644
index 0000000..0b644a7
--- /dev/null
+++ b/package/gcc/5.4.0/950-honor-SOURCE_DATE_EPOCH.patch
@@ -0,0 +1,213 @@
+From: Jérôme Pouiller <jezz at sysmic.org>
+Date: Fri, 04 Nov 2016 11:45:07 +0100
+Subject: [PATCH] Honor SOURCE_DATE_EPOCH
+
+Upstream status:
+ Accepted.
+ See http://gcc.gnu.org/git/?p=gcc.git;a=patch;h=e3e8c48c4a494d9da741c1c8ea6c4c0b7c4ff934
+
+Current patch is backported from equivalent written for gcc 6.1
+
+2016-04-28 Eduard Sanou <dhole at openmailbox.org>
+ Matthias Klose <doko at debian.org>
+
+ * 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 <dhole at openmailbox.org>
+ Matthias Klose <doko at debian.org>
+
+ * doc/cppenv.texi: Document SOURCE_DATE_EPOCH environment variable.
+
+libcpp/ChangeLog:
+
+2016-04-28 Eduard Sanou <dhole at openmailbox.org>
+ Matthias Klose <doko at debian.org>
+
+ * 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.
+
+Signed-off-by: Jérôme Pouiller <jezz at sysmic.org>
+
+---
+ gcc/c-family/c-common.c | 33 +++++++++++++++++++++++++++++++++
+ gcc/c-family/c-common.h | 6 ++++++
+ gcc/c-family/c-lex.c | 3 +++
+ gcc/doc/cppenv.texi | 17 +++++++++++++++++
+ libcpp/include/cpplib.h | 3 +++
+ libcpp/init.c | 7 +++++++
+ libcpp/internal.h | 4 ++++
+ libcpp/macro.c | 21 ++++++++++++++-------
+ 8 files changed, 87 insertions(+), 7 deletions(-)
+
+--- 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"
+--- a/gcc/c-family/c-common.h
++++ b/gcc/c-family/c-common.h
+@@ -1437,4 +1437,10 @@ extern bool contains_cilk_spawn_stmt (tr
+ 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 */
+--- 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_
+ 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:
+--- 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
++
++ at 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
++ at 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
+--- a/libcpp/include/cpplib.h
++++ b/libcpp/include/cpplib.h
+@@ -775,6 +775,9 @@ extern void cpp_init_special_builtins (c
+ /* 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 *);
+--- a/libcpp/init.c
++++ b/libcpp/init.c
+@@ -530,6 +530,13 @@ cpp_init_builtins (cpp_reader *pfile, in
+ _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
+--- 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;
+--- a/libcpp/macro.c
++++ b/libcpp/macro.c
+@@ -350,13 +350,20 @@ _cpp_builtin_macro_text (cpp_reader *pfi
+ 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)
+ {
--
1.9.1
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