From 0074a7c4ac4b3455db283f47b52e1d9427017348 Mon Sep 17 00:00:00 2001
From: Martin Stein <martin.stein@genode-labs.com>
Date: Tue, 29 Jun 2021 12:06:26 +0200
Subject: [PATCH] tool/depot: fix forwarding of CCACHE

The depot tool 'build_bin_archive' used to ask only whether CCACHE is empty or
not and, if it wasn't empty, the tool added 'CCACHE := yes' to the build.conf
of the temporary build dir. This caused the sub-build processes to use ccache
even when the top-level CCACHE variable was set to a bogus value.

Also adds documentation of the CCACHE variable to the help message of the
'build' and 'build_bin_archive' tool.

Ref #4212
---
 tool/depot/build                |  2 ++
 tool/depot/mk/build_bin_archive | 11 +++++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/tool/depot/build b/tool/depot/build
index eeaec6ef25..d3b9818b9a 100755
--- a/tool/depot/build
+++ b/tool/depot/build
@@ -45,6 +45,8 @@ define HELP_MESSAGE
     KEEP_BUILD_DIR=1   Do not remove build directories of built binary
                        packages. This is useful for debugging build
                        problems.
+
+    CCACHE=1           Compiler calls will use the C/C++ compiler cache.
 endef
 
 export GENODE_DIR := $(realpath $(dir $(MAKEFILE_LIST))/../..)
diff --git a/tool/depot/mk/build_bin_archive b/tool/depot/mk/build_bin_archive
index 59019633f0..37b9afdd20 100755
--- a/tool/depot/mk/build_bin_archive
+++ b/tool/depot/mk/build_bin_archive
@@ -12,11 +12,12 @@ define HELP_MESSAGE
 
   usage:
 
-    $(firstword $(MAKEFILE_LIST)) <src-name> SPEC=<spec> USER=<user>
+    $(firstword $(MAKEFILE_LIST)) <src-name> SPEC=<spec> USER=<user> CCACHE=<ccache>
 
     <src-name>   name of the source archive to build
     <spec>       build spec, e.g., x86_32, x86_64
     <user>       identity of the archive creator
+    <ccache>     compiler calls will use the C/C++ compiler cache if this is 1
 
 endef
 
@@ -158,12 +159,18 @@ ifneq ($(MISSING_API_DIRS),)
 	@false
 endif
 
+ifeq ($(CCACHE),1)
+BUILD_CONF_CCACHE := yes
+else
+BUILD_CONF_CCACHE :=
+endif
+
 $(BUILD_CONF): checked_src_archive checked_api_archives
 	$(VERBOSE)mkdir -p $(dir $@)
 	$(VERBOSE) \
 	( echo "GENODE_DIR := $(GENODE_DIR)"; \
 	  echo "BASE_DIR := $(GENODE_DIR)/repos/base"; \
-	  echo "override CCACHE := $(if $(CCACHE),yes)"; \
+	  echo "override CCACHE := $(BUILD_CONF_CCACHE)"; \
 	  echo "REPOSITORIES := $(SRC_DIR)"; \
 	  for api in $(USED_APIS); do \
 	      echo "REPOSITORIES += $(DEPOT_API_DIR)/$$api"; done \