c-common.c (get_source_date_epoch): New function...

gcc/c-family/ChangeLog:

2016-04-28  Eduard Sanou  <dhole@openmailbox.org>
	    Matthias Klose  <doko@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@openmailbox.org>
	    Matthias Klose  <doko@debian.org>

	* doc/cppenv.texi: Document SOURCE_DATE_EPOCH environment variable.

libcpp/ChangeLog:

2016-04-28  Eduard Sanou  <dhole@openmailbox.org>
	    Matthias Klose  <doko@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.

Co-Authored-By: Matthias Klose <doko@debian.org>

From-SVN: r235550

6 files changed, 72 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index face26b..a41b8e0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-04-28  Eduard Sanou  <dhole@openmailbox.org>
+	    Matthias Klose  <doko@debian.org>
+
+	* doc/cppenv.texi: Document SOURCE_DATE_EPOCH environment variable.
+
 2016-04-28  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/70777
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index ac3be53..8b1e764 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,12 @@
+2016-04-28  Eduard Sanou  <dhole@openmailbox.org>
+	    Matthias Klose  <doko@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.
+
 2015-04-27  Ryan Burn  <contact@rnburn.com>
 
 	PR c++/69024
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 1f0d76a..c086dee 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -12784,4 +12784,37 @@ valid_array_size_p (location_t loc, tree type, tree name)
   return true;
 }
 
+/* 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 1309549..3a7805f 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1471,4 +1471,9 @@ extern bool valid_array_size_p (location_t, tree, tree);
 extern bool cilk_ignorable_spawn_rhs_op (tree);
 extern bool cilk_recognize_spawn (tree, tree *);
 
+/* 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 6b020a4..ff7eb25 100644
--- a/gcc/c-family/c-lex.c
+++ b/gcc/c-family/c-lex.c
@@ -388,6 +388,9 @@ 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 22c8cb3..e958e93 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