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path: root/src/internal/libc.c
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2012-10-11i386 vsyscall support (vdso-provided sysenter/syscall instruction based)Rich Felker-0/+1
this doubles the performance of the fastest syscalls on the atom I tested it on; improvement is reportedly much more dramatic on worst-case cpus. cannot be used for cancellable syscalls.
2012-07-27save AT_HWCAP from auxv for subsequent use in machine-specific codeRich Felker-0/+2
it's expected that this will be needed/useful only in asm, so I've given it its own symbol that can be addressed in pc-relative ways from asm rather than adding a field in the __libc structure which would require hard-coding the offset wherever it's used.
2012-02-24new attempt at working around the gcc 3 visibility bugRich Felker-0/+4
since gcc is failing to generate the necessary ".hidden" directive in the output asm, generate it explicitly with an __asm__ statement...
2012-02-24remove useless attribute visibility from definitionsRich Felker-1/+1
this was a failed attempt at working around the gcc 3 visibility bug affecting x86_64. subsequent patch will address it with an ugly but working hack.
2012-02-23cleanup and work around visibility bug in gcc 3 that affects x86_64Rich Felker-1/+1
in gcc 3, the visibility attribute must be placed on both the declaration and on the definition. if it's omitted from the definition, the compiler fails to emit the ".hidden" directive in the assembly, and the linker will either generate textrels (if supported, such as on i386) or refuse to link (on targets where certain types of textrels are forbidden or impossible without further assumptions about memory layout, such as on x86_64). this patch also unifies the decision about when to use visibility into libc.h and makes the visibility in the utf-8 state machine tables based on libc.h rather than a duplicate test.
2011-02-24various changes in preparation for dynamic linking supportRich Felker-1/+1
prefer using visibility=hidden for __libc internal data, rather than an accessor function, if the compiler has visibility. optimize with -O3 for PIC targets (shared library). without heavy inlining, reloading the GOT register in small functions kills performance. 20-30% size increase for a single libc.so is not a big deal, compared to comparaible size increase in every static binaries. use -Bsymbolic-functions, not -Bsymbolic. global variables are subject to COPY relocations, and thus binding their addresses in the library at link time will cause library functions to read the wrong (original) copies instead of the copies made in the main program's bss section. add entry point, _start, for dynamic linker.
2011-02-20use an accessor function for __libc data pointer when compiled as PICRich Felker-1/+9
prior to this change, a large portion of libc was unusable prior to relocation by the dynamic linker, due to dependence on the global data in the __libc structure and the need to obtain its address through the GOT. with this patch, the accessor function __libc_loc is now able to obtain the address of __libc via PC-relative addressing without using the GOT. this means the majority of libc functionality is now accessible right away. naturally, the above statements all depend on having an architecture where PC-relative addressing and jumps/calls are feasible, and a compiler that generates the appropriate code.
2011-02-12initial check-in, version 0.5.0v0.5.0Rich Felker-0/+3