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Diffstat (limited to 'gcc-backup/README')
| -rw-r--r-- | gcc-backup/README | 41 |
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diff --git a/gcc-backup/README b/gcc-backup/README new file mode 100644 index 0000000..fdac223 --- /dev/null +++ b/gcc-backup/README @@ -0,0 +1,41 @@ +What is gcc-backup +================== + +gcc-backup is a directory to backup critical runtime +libraries used by gcc to link in code too big to inline it +from code generator. + +See gcc/doc/libgcc.texi doc in gcc source tree. + +gcc-config is responsible to back up libgcc_s.so.* and it's +runtime dependencies. + +Which systems needed this backup +================================ + +During normal system operation these libraries should not be +needed (unless gcc installation is somehow completely broken). + +The main use case for libgcc-backup is booting of a system +with the following properties: +- '/usr' mount is separate from '/' mount +- AND binaries in /bin (say, /bin/bash) are executed before + /usr is mounted + +Which systems link libgcc_s.so in +================================= + +By default gcc attempts to link libgcc_s.so in into every +binary and shared library. If code generator happens to +generate the code that does not refer libgcc_s.so then +-Wl,--as-needed linker option omits the dependency. + +Thus any system might have libgcc_s.so linked into any binary +or shared library. + +What goes into this directory +============================= + +- libgcc_s.so.* itself: gcc driver attempts to link it in as-is +- libunwind.so.*: ia64-*-linux only, a runtime dependency of + libgcc_so.so.* |