Old build problem: unpack200 failure when setting OTHER_CXXFLAGS in environment (original) (raw)

David Holmes david.holmes at oracle.com
Mon Mar 12 04:48:15 UTC 2012

This is a blast from the past:

http://mail.openjdk.java.net/pipermail/build-dev/2007-May/000026.html

but the above issue and patch seem to have been ignored. I just ran into this myself.

/export/users/dh198349/jdk8/builds/b01/se8-linux-i586-ea/tmp/sun/com.sun.java.util.jar.pack/unpack-cmd/obj/main.o: In function unpacker::run(int, char**)': main.cpp:(.text+0xe0b): undefined reference to gunzip::init(unpacker*)' main.cpp:(.text+0xe1d): undefined reference to `gunzip::start(int)' collect2: ld returned 1 exit status make[7]: *** [/export/users/dh198349/jdk8/builds/b01/se8-linux-i586-ea/bin/unpack200] Error 1

The basic issue is one of recursive makes, with conditionally set variables that might also be set externally in the environment. Here's an example Makefile:

build: unpack

ifdef STANDALONE FLAGS+=-XstandAlone else FLAGS+=-Xcombined endif

unpack: @make STANDALONE=true unpack_exe

build: @echo build FLAGS = $(FLAGS) unpack_exe: @echo unpack_exe FLAGS = $(FLAGS)

.phony: build unpack unpack_exe

Here's a normal run:

make build make[1]: Entering directory /scratch/dh198349' unpack_exe FLAGS = -XstandAlone make[1]: Leaving directory /scratch/dh198349' build FLAGS = -Xcombined

which is what we would expect. But if you now give FLAGS an initial external value:

FLAGS=external make build make[1]: Entering directory /scratch/dh198349' unpack_exe FLAGS = external -Xcombined -XstandAlone make[1]: Leaving directory /scratch/dh198349' build FLAGS = external -Xcombined

Yikes! Now unpack_exe sees both the STANDALONE and non-STANDALONE value of FLAGS. This is because make re-exports any variable that came in from the environment. So when the top-level make is called, FLAGS==external, and to that the Makefile adds -Xcombined, so the sub-make effectively becomes:

make FLAGS="external -Xcombined" STANDALONE=true unpack_exe

Here's one way to fix this:

save original incoming FLGS

ORIG_FLAGS := $(FLAGS)

hide any locally modified value of FLAGS

unexport FLAGS

build: unpack

ifdef STANDALONE

override to allow sub-make to add to FLAGS

override FLAGS+=-XstandAlone else FLAGS+=-Xcombined endif

unpack: # Send in ORIG_FLAGS as FLAGS @make FLAGS=$(ORIG_FLAGS) STANDALONE=true unpack_exe

build: @echo build FLAGS = $(FLAGS) unpack_exe: @echo unpack_exe FLAGS = $(FLAGS)

.phony: build unpack unpack_exe

Or as per the original Patch, use a different variable in the Makefile to that set in the environment.

David

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