From 02c74b5bee114d4eefed0ddceb3ca83b5e8e115b Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sun, 13 Dec 2009 11:46:29 -0500
Subject: [PATCH] Document OBJCACHE and OBJCACHE_JOBS

---
 Makefile.in     |  6 +++---
 bin/verilator   | 15 ++++++++++++++-
 src/Makefile.in | 11 +++++------
 3 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/Makefile.in b/Makefile.in
index 24aec54e2..578da68a2 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -145,11 +145,11 @@ DISTFILES := $(DISTFILES_INC)
 
 VL_INST_MAN_FILES = verilator.1
 
-ifeq ($(OBJCACHE_HOSTS),)
-export OBJCACHE_JOBS :=
-else
+ifeq ($(OBJCACHE_JOBS),)
+ifneq ($(OBJCACHE_HOSTS),)
 export OBJCACHE_JOBS := -j $(shell objcache --jobs "$(OBJCACHE_HOSTS)")
 endif
+endif
 
 default: all
 all: all_nomsg msg_test
diff --git a/bin/verilator b/bin/verilator
index 9fe7c4a2f..cb9546fef 100755
--- a/bin/verilator
+++ b/bin/verilator
@@ -1004,6 +1004,18 @@ After running Make, the C++ compiler should produce the following:
 
 =over 4
 
+=item OBJCACHE
+
+Optionally specifies a caching or distribution program to place in front of
+all runs of the C++ Compiler.  For example, "objcache --read --write", or
+"ccache".  If using distcc, it would generally be run under either objcache
+or ccache; see the documentation for those programs.
+
+=item OBJCACHE_JOBS
+
+Optionally lists Make flags that specifies parallel make jobs.  For example
+a 4 CPU system may use "-j 6" to request 6 parallel compiles when making.
+
 =item SYSTEMC
 
 Required for SystemC output mode.  If set, specifies the directory
@@ -2525,7 +2537,8 @@ to compile on parallel machines and avoid compilations altogether.  See the
 --output-split option, and the web for the ccache, distcc and icecream
 packages, and the Make::Cache package available from
 L<http://www.veripool.org/>. Make::Cache will skip GCC runs between
-identical source builds, even across different users.
+identical source builds, even across different users.  You can use the
+OBJCACHE environment variable to use these CC wrappers.
 
 =item Why do so many files need to recompile when I add a signal?
 
diff --git a/src/Makefile.in b/src/Makefile.in
index 79a3e702a..cebdc6591 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -40,11 +40,10 @@ export OBJCACHE_HOSTS := $(shell rschedule --no-allow-reserved --similar hostnam
  endif
 endif
 
-ifeq ($(OBJCACHE_HOSTS),)
-export OBJCACHE :=
-else
+ifeq ($(OBJCACHE_JOBS),)
+ifneq ($(OBJCACHE_HOSTS),)
 export OBJCACHE_JOBS := -j $(shell objcache --jobs "$(OBJCACHE_HOSTS)")
-export OBJCACHE := @objcache --read --write
+endif
 endif
 
 UNDER_GIT = $(wildcard ../.git/logs/HEAD)
@@ -65,13 +64,13 @@ ifeq ($(VERILATOR_NO_OPT_BUILD),1)	# Faster laptop development... One build
 	@-cp -p $<.exe $@.exe
 else
 ../verilator_bin: obj_opt prefiles
-	cd obj_opt && $(MAKE)                  TGT=../$@ -f ../Makefile_obj serial
+	cd obj_opt && $(MAKE) -j 1             TGT=../$@ -f ../Makefile_obj serial
 	cd obj_opt && $(MAKE) $(OBJCACHE_JOBS) TGT=../$@ -f ../Makefile_obj
 endif
 
 dbg: ../verilator_bin_dbg
 ../verilator_bin_dbg: obj_dbg prefiles
-	cd obj_dbg && $(MAKE)                  TGT=../$@ VL_DEBUG=1 -f ../Makefile_obj serial
+	cd obj_dbg && $(MAKE) -j 1             TGT=../$@ VL_DEBUG=1 -f ../Makefile_obj serial
 	cd obj_dbg && $(MAKE) $(OBJCACHE_JOBS) TGT=../$@ VL_DEBUG=1 -f ../Makefile_obj
 
 prefiles::