[Buildroot] [PATCH] toolchain/toolchain-wrapper.c: set CCACHE env variables only when ccache is enabled

* [Buildroot] [PATCH] toolchain/toolchain-wrapper.c: set CCACHE env variables only when ccache is enabled
@ 2022-08-06 19:58 Thomas Petazzoni via buildroot
  2023-02-07 11:29 ` Yann E. MORIN
  0 siblings, 1 reply; 2+ messages in thread
From: Thomas Petazzoni via buildroot @ 2022-08-06 19:58 UTC (permalink / raw)
  To: buildroot
  Cc: Thomas De Schampheleire, Giulio Benetti, Romain Naour,
	Yann E. MORIN, Thomas Petazzoni

This commit modifies the toolchain-wrapper to make sure that the
CCACHE_COMPILERCHECK and CCACHE_BASEDIR are only set if ccache support
is enabled. Indeed, when BR2_USE_CCACHE is not set (or to a value
different than 1), we don't call the compiler with ccache, so there is
no reason to set those ccache environment variables, and they could
potentially conflict with a separate usage of ccache, outside of
Buildroot, for example when using the Buildroot SDK.

In particular, the value of CCACHE_BASEDIR doesn't not make any sense
when the Buildroot toolchain is not used during the Buildroot build,
as it points to the output directory $(BASE_DIR).

We pay attention to also not show those variables as being set in the
BR2_DEBUG_WRAPPER dump.

To help a little bit with this, a ccache_enabled boolean is introduced
to indicate when ccache is being used.

There is still quite a bit of #ifdef-ery involved, but it's not easy
to find a simpler way to organize the code.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
 toolchain/toolchain-wrapper.c | 49 +++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/toolchain/toolchain-wrapper.c b/toolchain/toolchain-wrapper.c
index 37b24dd24a..ee1fdf3c71 100644
--- a/toolchain/toolchain-wrapper.c
+++ b/toolchain/toolchain-wrapper.c
@@ -507,10 +507,28 @@ int main(int argc, char **argv)
 
 	exec_args = args;
 #ifdef BR_CCACHE
-	/* If BR2_USE_CCACHE is not defined, or its value is not 1,
-	 * skip the ccache call */
+	/* If BR2_USE_CCACHE is set and its value is 1, enable ccache
+	 * usage */
 	char *br_use_ccache = getenv("BR2_USE_CCACHE");
-	if (!br_use_ccache || strncmp(br_use_ccache, "1", strlen("1")))
+	bool ccache_enabled = br_use_ccache && !strncmp(br_use_ccache, "1", strlen("1"));
+
+	if (ccache_enabled) {
+#ifdef BR_CCACHE_HASH
+		/* Allow compilercheck to be overridden through the environment */
+		if (setenv("CCACHE_COMPILERCHECK", "string:" BR_CCACHE_HASH, 0)) {
+			perror(__FILE__ ": Failed to set CCACHE_COMPILERCHECK");
+			return 3;
+		}
+#endif
+#ifdef BR_CCACHE_BASEDIR
+		/* Allow compilercheck to be overridden through the environment */
+		if (setenv("CCACHE_BASEDIR", BR_CCACHE_BASEDIR, 0)) {
+			perror(__FILE__ ": Failed to set CCACHE_BASEDIR");
+			return 3;
+		}
+#endif
+	} else
+		/* ccache is disabled, skip it */
 		exec_args++;
 #endif
 
@@ -518,12 +536,14 @@ int main(int argc, char **argv)
 	if (debug > 0) {
 		fprintf(stderr, "Toolchain wrapper executing:");
 #ifdef BR_CCACHE_HASH
-		fprintf(stderr, "%sCCACHE_COMPILERCHECK='string:" BR_CCACHE_HASH "'",
-			(debug == 2) ? "\n    " : " ");
+		if (ccache_enabled)
+			fprintf(stderr, "%sCCACHE_COMPILERCHECK='string:" BR_CCACHE_HASH "'",
+				(debug == 2) ? "\n    " : " ");
 #endif
 #ifdef BR_CCACHE_BASEDIR
-		fprintf(stderr, "%sCCACHE_BASEDIR='" BR_CCACHE_BASEDIR "'",
-			(debug == 2) ? "\n    " : " ");
+		if (ccache_enabled)
+			fprintf(stderr, "%sCCACHE_BASEDIR='" BR_CCACHE_BASEDIR "'",
+				(debug == 2) ? "\n    " : " ");
 #endif
 		for (i = 0; exec_args[i]; i++)
 			fprintf(stderr, "%s'%s'",
@@ -531,21 +551,6 @@ int main(int argc, char **argv)
 		fprintf(stderr, "\n");
 	}
 
-#ifdef BR_CCACHE_HASH
-	/* Allow compilercheck to be overridden through the environment */
-	if (setenv("CCACHE_COMPILERCHECK", "string:" BR_CCACHE_HASH, 0)) {
-		perror(__FILE__ ": Failed to set CCACHE_COMPILERCHECK");
-		return 3;
-	}
-#endif
-#ifdef BR_CCACHE_BASEDIR
-	/* Allow compilercheck to be overridden through the environment */
-	if (setenv("CCACHE_BASEDIR", BR_CCACHE_BASEDIR, 0)) {
-		perror(__FILE__ ": Failed to set CCACHE_BASEDIR");
-		return 3;
-	}
-#endif
-
 	if (execv(exec_args[0], exec_args))
 		perror(path);
 
-- 
2.37.1

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