Giving manual CXXFLAGS to make results in errors when compiling #7411

I am compiling v0.12.0rc2 for Raspbian Jessie on a Raspberry Pi 2. Since it only has 1 GB of memory and no swap, I am following Luke-jr's workaround in issue 6658 to make gcc use less memory by options for more aggressive garbage collecting.

When I invoke make:

$ make CXXFLAGS="--param ggc-min-expand=1 --param ggc-min-heapsize=32768"

It solves the memory use problem for the first part of the build, however it gets to compiling leveldb objects and errors:

Building LevelDB ...
make[3]: Entering directory '/home/jarret/git/bitcoin/src/leveldb'
g++ --param ggc-min-expand=1 --param ggc-min-heapsize=32768 -c helpers/memenv/memenv.cc -o helpers/memenv/memenv.o
helpers/memenv/memenv.cc:5:35: fatal error: helpers/memenv/memenv.h: No such file or directory
#include "helpers/memenv/memenv.h"
                               ^

I see that g++ is getting invoked here without the full set of normal flags including the '-I.' to find the memenv.h header in this error.

If I reissue the make in debug mode without specifying any manual CXXFLAGS:

$ make -d

I see that the normal compilation of this source file looks like this:

g++ -I. -I./include -std=c++0x -fno-builtin-memcmp -pthread -DOS_LINUX -DLEVELDB_PLATFORM_POSIX -DLEVELDB_ATOMIC_PRESENT -Wstack-protector -fstack-protector-all -fPIE --param ggc-min-expand=1 --param ggc-min-heapsize=32768 -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -DHAVE_BUILD_INFO -D__STDC_FORMAT_MACROS -D_FILE_OFFSET_BITS=64 -D__STDC_LIMIT_MACROS -c helpers/memenv/memenv.cc -o helpers/memenv/memenv.o

For which I find that it now doing this correctly, and it successfully builds. Somehow, it gets the ggc-min-expand and ggc-min-heapsize parameters in there too, which must be residual from the first invocation - strange.

Workaround 1:

Once leveldb is done building, I can Ctrl-C the build and then go back to the manual CXXFLAGS. This builds fine until the end without running out of memory.

Workaround 2:

Specify the CXXFLAGS at configure time:

$ ./configure --disable-wallet CXXFLAGS="--param ggc-min-expand=1 --param ggc-min-heapsize=32768"

I think this is typical/expected for automake?

I always pass my custom CXXFLAGS, CPPFLAGS, CFLAGS to ./configure instead of make. Maybe that works better? At least I've never had issues.

Yes, I can confirm that giving the flags to './configure' works as expected. Giving them to 'make' only trips up at the leveldb part as described.

Yep, what they said. Pass them to configure so they persist.

Ok, closing this issue then.