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The BR2_ARCH_HAS_ATOMICS was added because on ARC, atomic instructions may not be provided by the architecture and therefore the compiler does not provide the __sync_*() built-ins. However, since then, icu was changed and is now able to use C++11 atomics, or even no atomic operations at all. In fact, icu will: * If possible, it will use C++11 atomics, which internally rely on the __atomic built-ins. These are available since gcc 4.7, and all architectures provide it. On some architectures, you *must* link with libatomic, on some other architectures, they are available built-in, but in all cases, linking against libatomic does not harm. Thanks to this, even ARC with no atomic support (which was the original reason for adding the BR2_ARCH_HAS_ATOMICS) dependency builds fine, provided -latomic is added to LIBS. * If C++11 atomics are not available, then it falls back to __sync_*() built-ins, which allows compilers older than 4.7 to be supported. * If really no atomic mechanism is available, then it falls back to a basic implementation based on a mutex. Conclusion: - The BR2_ARCH_HAS_ATOMICS dependency is no longer needed. - We need to link with -latomic when gcc >= 4.7 is used. Note that reverse dependencies of icu are also changed accordingly. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> |
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| boot | ||
| configs | ||
| docs | ||
| fs | ||
| linux | ||
| package | ||
| support | ||
| system | ||
| toolchain | ||
| .defconfig | ||
| .gitignore | ||
| CHANGES | ||
| Config.in | ||
| Config.in.legacy | ||
| COPYING | ||
| Makefile | ||
| Makefile.legacy | ||
| README | ||
Buildroot is a simple, efficient and easy-to-use tool to generate embedded Linux systems through cross-compilation. The documentation can be found in docs/manual. You can generate a text document with 'make manual-text' and read output/docs/manual/manual.text. Online documentation can be found at http://buildroot.org/docs.html To build and use the buildroot stuff, do the following: 1) run 'make menuconfig' 2) select the target architecture and the packages you wish to compile 3) run 'make' 4) wait while it compiles 5) find the kernel, bootloader, root filesystem, etc. in output/images You do not need to be root to build or run buildroot. Have fun! Buildroot comes with a basic configuration for a number of boards. Run 'make list-defconfigs' to view the list of provided configurations. Please feed suggestions, bug reports, insults, and bribes back to the buildroot mailing list: buildroot@buildroot.org You can also find us on #buildroot on Freenode IRC.