From 994c84fb40fd74199feb1229e40acb538993c0f2 Mon Sep 17 00:00:00 2001
From: Primiano Tucci <primiano@google.com>
Date: Mon, 2 Jun 2014 17:37:38 +0100
Subject: [PATCH] Introduce CC/CXX/JAVAC_WRAPPER to wrap the calls to the
 compiler.

This is to make it possible to wrap the compiler invocations with
custom wrappers (e.g., distcc/goma) by setting the CC_WRAPPER,
CXX_WRAPPER, JAVAC_WRAPPER variables in the build environment (without
having to know in advance the path to the compiler)

Change-Id: Ide800c24f0c2ebbb1cfb358bd8f99ec8a9d41253
---
 core/combo/javac.mk  |  9 ++++++++-
 core/combo/select.mk | 21 ++++++++++++++-------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/core/combo/javac.mk b/core/combo/javac.mk
index 4248af0a0..7f91aa9dd 100644
--- a/core/combo/javac.mk
+++ b/core/combo/javac.mk
@@ -1,7 +1,7 @@
 # Selects a Java compiler.
 #
 # Inputs:
-#	CUSTOM_JAVA_COMPILER -- "eclipse", "openjdk". or nothing for the system 
+#	CUSTOM_JAVA_COMPILER -- "eclipse", "openjdk". or nothing for the system
 #                           default
 #	ALTERNATE_JAVAC -- the alternate java compiler to use
 #
@@ -22,6 +22,13 @@ else
 JAVACC := $(ALTERNATE_JAVAC)
 endif
 
+# The actual compiler can be wrapped by setting the JAVAC_WRAPPER var.
+ifdef JAVAC_WRAPPER
+    ifneq ($(JAVAC_WRAPPER),$(firstword $(JAVACC)))
+        JAVACC := $(JAVAC_WRAPPER) $(JAVACC)
+    endif
+endif
+
 # Whatever compiler is on this system.
 ifeq ($(BUILD_OS), windows)
     COMMON_JAVAC := development/host/windows/prebuilt/javawrap.exe -J-Xmx256m \
diff --git a/core/combo/select.mk b/core/combo/select.mk
index 8234a8fcb..98697e026 100644
--- a/core/combo/select.mk
+++ b/core/combo/select.mk
@@ -92,13 +92,20 @@ ifneq ($(USE_CCACHE),)
   # Check that the executable is here.
   ccache := $(strip $(wildcard $(ccache)))
   ifdef ccache
-    # prepend ccache if necessary
-    ifneq ($(ccache),$(firstword $($(combo_var_prefix)CC)))
-      $(combo_var_prefix)CC := $(ccache) $($(combo_var_prefix)CC)
-    endif
-    ifneq ($(ccache),$(firstword $($(combo_var_prefix)CXX)))
-      $(combo_var_prefix)CXX := $(ccache) $($(combo_var_prefix)CXX)
-    endif
+    CC_WRAPPER ?= $(ccache)
+    CXX_WRAPPER ?= $(ccache)
     ccache =
   endif
 endif
+
+# The C/C++ compiler can be wrapped by setting the CC/CXX_WRAPPER vars.
+ifdef CC_WRAPPER
+  ifneq ($(CC_WRAPPER),$(firstword $($(combo_var_prefix)CC)))
+    $(combo_var_prefix)CC := $(CC_WRAPPER) $($(combo_var_prefix)CC)
+  endif
+endif
+ifdef CXX_WRAPPER
+  ifneq ($(CXX_WRAPPER),$(firstword $($(combo_var_prefix)CXX)))
+    $(combo_var_prefix)CXX := $(CXX_WRAPPER) $($(combo_var_prefix)CXX)
+  endif
+endif