glog: disable on blackfin

glog fails to build on blackfin for following reasons,

1. http://autobuild.buildroot.net/results/c70/c704c70ae2f066f85dd6a5fa6a73789bc358d368/

when when BR2_BINFMT_FDPIC=y

../usr/include/bits/elf-fdpic.h: In function 'void* __reloc_pointer(void*, const elf32_fdpic_loadmap*)':
../usr/bfin-buildroot-linux-uclibc/sysroot/usr/include/bits/elf-fdpic.h:95: error: invalid use of 'void'

code snippet at line 95 in elf-fdpic.h
-------------------------------------------------------
unsigned long offset = p - (void*)map->segs[c].p_vaddr;
-------------------------------------------------------

void pointer addition and subtraction is not allowed in C++ as it has undetermined size, however in C with language extension it is possible because sizeof void is treated as one byte.

2. http://autobuild.buildroot.net/results/75d/75d17ceb764c2c1136047c089a0c554770ca98a4/

when BR2_BINFMT_FLAT=y

src/symbolize.cc:110:19: error: dlfcn.h: No such file or directory

with flat binary, programming interface to dynamic linker loader is not available even though BR2_BINFMT_FLAT_SHARED is selected.

As arch doesn't support MMU and thus available file formats are FDPIC and FLAT. With either of these selected above failure occurs. For failure 1, issue is in toolchain and for 2, arch support is not available. So disable glog for blackfin.

---
 package/glog/Config.in | 4 ++++
 1 file changed, 4 insertions(+)

index aed0a3e..350afe2 100644
@@ -2,10 +2,14 @@ config BR2_PACKAGE_GLOG
 	bool "glog"
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
+	# build issues with C++ compiler with elf-fdpic and
+	# can't use libdl with flat target binary file format
+	depends on !BR2_bfin
 	help
 	  C++ implementation of the Google logging module
 
 	  https://github.com/google/glog
 
 comment "glog needs a toolchain w/ C++, threads"
+	depends on !BR2_bfin
 	depends on !BR2_INSTALL_LIBSTDCPP || !BR2_TOOLCHAIN_HAS_THREADS

1.9.1

Rahul,

I believe this is more a toolchain-specific problem, not really a Blackfin problem per-se. So we should instead disable this package on the specific Blackfin external toolchains.

Then you should add a dependency on !BR2_STATIC_LIBS: there are other architectures that can lack dlfcn.h. And in fact all architectures can be missing dlfcn.h if BR2_STATIC_LIBS=y.

Best regards,

Thomas

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com