[Buildroot] [PATCH] toolchain/toolchain-wrapper: let recent GCC handle SOURCE_DATE_EPOCH
John Keeping
john at metanate.com
Fri Jun 26 15:49:27 UTC 2020
When using precompiled headers, changing any macros defined on the
command line will invalidate the precompiled header. With
toolchain-wrapper adding __DATE__ and __TIME__, any commits to Buildroot
will invalidate incremental builds regardless of whether the precompiled
header actually uses those values (affecting _OVERRIDE_SRCDIR).
GCC-7 and later support SOURCE_DATE_EPOCH and use it to define __DATE__
and __TIME__ internally, avoiding any impact on precompiled headers.
Disable the custom handling in toolchain-wrapper if GCC is version 7 or
newer.
Signed-off-by: John Keeping <john at metanate.com>
---
toolchain/toolchain-wrapper.c | 10 ++++++++++
toolchain/toolchain-wrapper.mk | 3 +++
2 files changed, 13 insertions(+)
diff --git a/toolchain/toolchain-wrapper.c b/toolchain/toolchain-wrapper.c
index 39e9f0850f..0fb6064b1c 100644
--- a/toolchain/toolchain-wrapper.c
+++ b/toolchain/toolchain-wrapper.c
@@ -179,6 +179,7 @@ static void check_unsafe_path(const char *arg,
}
}
+#ifdef BR_NEED_SOURCE_DATE_EPOCH
/* Returns false if SOURCE_DATE_EPOCH was not defined in the environment.
*
* Returns true if SOURCE_DATE_EPOCH is in the environment and represent
@@ -232,6 +233,15 @@ bool parse_source_date_epoch_from_env(void)
}
return true;
}
+#else
+bool parse_source_date_epoch_from_env(void)
+{
+ /* The compiler is recent enough to handle SOURCE_DATE_EPOCH itself
+ * so we do not need to do anything here.
+ */
+ return false;
+}
+#endif
int main(int argc, char **argv)
{
diff --git a/toolchain/toolchain-wrapper.mk b/toolchain/toolchain-wrapper.mk
index 09dda17890..4d45e3d8a2 100644
--- a/toolchain/toolchain-wrapper.mk
+++ b/toolchain/toolchain-wrapper.mk
@@ -28,6 +28,9 @@ TOOLCHAIN_WRAPPER_OPTS += -ffile-prefix-map=$(BASE_DIR)=buildroot
else
TOOLCHAIN_WRAPPER_OPTS += -D__FILE__=\"\" -D__BASE_FILE__=\"\" -Wno-builtin-macro-redefined
endif
+ifneq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_7),y)
+TOOLCHAIN_WRAPPER_OPTS += -DBR_NEED_SOURCE_DATE_EPOCH
+endif
endif
# We create a list like '"-mfoo", "-mbar", "-mbarfoo"' so that each flag is a
--
2.27.0
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