- 24 4月, 2015 1 次提交
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由 Rich Felker 提交于
this slightly reduces the code size cost of TLS/thread-pointer for static linking since __init_tp can be inlined into its only caller and removed. this is analogous to the handling of __init_libc in __libc_start_main, where the function only has external linkage when it needs to be called from the dynamic linker.
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- 23 4月, 2015 1 次提交
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由 Rich Felker 提交于
the implicit-operand form of fucomip is rejected by binutils 2.19 and perhaps other versions still in use. writing both operands explicitly fixes the issue. there is no change to the resulting output. commit a732e80d was the source of this regression.
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- 22 4月, 2015 13 次提交
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由 Rich Felker 提交于
use CAS instead of swap since it's lighter for most archs, and keep EBUSY in the lock value so that the old value obtained by CAS can be used directly as the return value for pthread_spin_trylock.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
the motivation for this change is that the extra declaration (with or without visibility) using "struct _IO_FILE" instead of "FILE" seems to trigger a bug in gcc 3.x where it considers the types mismatched. however, this change also results in slightly better code and it is valid because (1) these three objects are constant, and (2) applying the & operator to any of them is invalid C, since they are not even specified to be objects. thus it does not matter if the application and libc see different addresses for them, as long as the (initial, unchanging) value is seen the same by both.
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由 Rich Felker 提交于
these are used as hidden by asm files (and such use is the whole reason they exist), but their actual definitions were not hidden.
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由 Rich Felker 提交于
commit f9cccfc1 left behind the part in libc.c; remove it too.
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由 Rich Felker 提交于
part of the goal here is to eliminate use of the ATTR_LIBC_VISIBILITY macro outside of libc.h, since it was never intended to be 'public'.
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由 Rich Felker 提交于
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由 Rich Felker 提交于
these were hacks to work around toolchains that could not properly optimize PIC accesses based on visibility and would generate GOT lookups even for hidden data, which broke the old dynamic linker. since commit f3ddd173 it no longer matters; the dynamic linker does not assume accessibility of this data until stage 3.
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由 Rich Felker 提交于
when the non-stub duplocale code was added as part of the locale framework in commit 0bc03091, the old code to memcpy the old locale object to the new one was left behind. the conditional for the memcpy no longer makes sense, because the conditions are now always-true when it's reached, and the memcpy is wrong because it clobbers the new->messages_name pointer setup just above. since the messages_name and ctype_utf8 members have already been copied, all that remains is the cat[] array. these pointers are volatile, so using memcpy to copy them is formally wrong; use a for loop instead.
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由 Rich Felker 提交于
the first switch already returns in the F_SETLKW code path so it need not be handled in the second switch. moreover the code in the second switch is wrong for the F_SETLKW command: it's not cancellable.
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由 Rich Felker 提交于
the leak was found by static analysis (reported by Alexander Monakov), not tested/observed, but seems to have occured both when failing due to O_EXCL, and in a race condition with O_CREAT but not O_EXCL where a semaphore by the same name was created concurrently.
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由 Rich Felker 提交于
the allocating path which can fail is for dynamic TLS, which can only occur at runtime, and the check for runtime was already made in the outer conditional.
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由 Rich Felker 提交于
commit 637dd2d3 introduced the checks for RTLD_DEFAULT and RTLD_NEXT here, claiming they fixed a regression, but the above conditional block clearly already covered these cases, and removing the checks produces no difference in the generated code.
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- 20 4月, 2015 5 次提交
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由 Rich Felker 提交于
this is implemented via the build system and does not affect source files. the idea is to use protected or hidden visibility to prevent the compiler from pessimizing function calls within a shared (or position-independent static) libc in the form of overhead setting up for a call through the PLT. the ld-time symbol binding via the -Bsymbolic-functions option already optimized out the PLT itself, but not the code in the caller needed to support a call through the PLT. on some archs this overhead can be substantial; on others it's trivial.
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由 Rich Felker 提交于
analogous to commit 646cb9a4 for sh.
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由 Rich Felker 提交于
these are perfectly fine with ld-time symbol binding, but otherwise result in textrels. they cannot be replaced with @PLT jump targets because the PLT thunks require a GOT register to be setup, so use a hidden alias instead.
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由 Rich Felker 提交于
analogous to commit 646cb9a4 for sh.
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由 Rich Felker 提交于
these are perfectly fine with ld-time symbol binding, but if the calls go through a PLT thunk, they are invalid because the caller does not setup a GOT register. use a hidden alias to bypass the issue.
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- 19 4月, 2015 4 次提交
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由 Rich Felker 提交于
analogous to commit 8ed66ecb for i386.
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由 Rich Felker 提交于
none of these are actual textrels because of ld-time binding performed by -Bsymbolic-functions, but I'm changing them with the goal of making ld-time binding purely an optimization rather than relying on it for semantic purposes. in the case of memmove's call to memcpy, making it explicit that the memmove asm is assuming the forward-copying behavior of the memcpy asm is desirable anyway; in case memcpy is ever changed, the semantic mismatch would be apparent while editing memmcpy.s.
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由 Rich Felker 提交于
this fixes truncation of error messages containing long pathnames or symbol names. the dlerror state was previously required by POSIX to be global. the resolution of bug 97 relaxed the requirements to allow thread-safe implementations of dlerror with thread-local state and message buffer.
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由 Alexander Monakov 提交于
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- 18 4月, 2015 9 次提交
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由 Szabolcs Nagy 提交于
this reverts the commit f29fea00 which was based on a bug in C99 and POSIX and did not match IEEE-754 http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1515.pdf
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由 Rich Felker 提交于
these functions are never called directly; only their addresses are used, so PLT indirections should never happen unless a broken application tries to redefine them, but it's still best to make them hidden.
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由 Szabolcs Nagy 提交于
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由 Rich Felker 提交于
this change is made in preparation to support linking without -Bsymbolic-functions.
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由 Rich Felker 提交于
commit 5fc14878 attempted to fix it, but neglected the fact that mips has branch delay slots.
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由 Rich Felker 提交于
the braf instruction's destination register is an offset from the address of the braf instruction plus 4 (or equivalently, the address of the next instruction after the delay slot). the code for dlsym was incorrectly computing the offset to pass using the address of the delay slot itself. in other places, a label was placed after the delay slot, but I find this confusing. putting the label on the branch instruction itself, and manually adding 4, makes it more clear which branch the offset in the constant pool goes with.
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由 Rich Felker 提交于
even hidden functions need @PLT symbol references; otherwise an absolute address is produced instead of a PC-relative one.
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由 Rich Felker 提交于
this caused the dynamic linker/startup code to abort when r0 happened to contain a negative value.
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由 Rich Felker 提交于
the conventional way to implement sigsetjmp is to save the signal mask then tail-call to setjmp; siglongjmp then restores the signal mask and calls longjmp. the problem with this approach is that a signal already pending, or arriving between unmasking of signals and restoration of the saved stack pointer, will have its signal handler run on the stack that was active before siglongjmp was called. this can lead to unbounded stack usage when siglongjmp is used to leave a signal handler. in the new design, sigsetjmp saves its own return address inside the extended part of the sigjmp_buf (outside the __jmp_buf part used by setjmp) then calls setjmp to save a jmp_buf inside its own execution. it then tail-calls to __sigsetjmp_tail, which uses the return value of setjmp to determine whether to save the current signal mask or restore a previously-saved mask. as an added bonus, this design makes it so that siglongjmp and longjmp are identical. this is useful because the __longjmp_chk function we need to add for ABI-compatibility assumes siglongjmp and longjmp are the same, but for different reasons -- it was designed assuming either can access a flag just past the __jmp_buf indicating whether the signal masked was saved, and act on that flag. however, early versions of musl did not have space past the __jmp_buf for the non-sigjmp_buf version of jmp_buf, so our setjmp cannot store such a flag without risking clobbering memory on (very) old binaries.
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- 15 4月, 2015 3 次提交
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由 Rich Felker 提交于
previously, the dynamic tlsdesc lookup functions and the i386 special-ABI ___tls_get_addr (3 underscores) function called __tls_get_addr when the slot they wanted was not already setup; __tls_get_addr would then in turn also see that it's not setup and call __tls_get_new. calling __tls_get_new directly is both more efficient and avoids the issue of calling a non-hidden (public API/ABI) function from asm. for the special i386 function, a weak reference to __tls_get_new is used since this function is not defined when static linking (the code path that needs it is unreachable in static-linked programs).
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由 Rich Felker 提交于
applying the attribute to a weak_alias macro was a hack. instead use a separate declaration to apply the visibility, and consolidate declarations together to avoid having visibility mess all over the file.
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由 Rich Felker 提交于
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- 14 4月, 2015 4 次提交
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由 Rich Felker 提交于
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由 Rich Felker 提交于
in a few places, non-hidden symbols were referenced from asm in ways that assumed ld-time binding. while these is no semantic reason these symbols need to be hidden, fixing the references without making them hidden was going to be ugly, and hidden reduces some bloat anyway. in the asm files, .global/.hidden directives have been moved to the top to unclutter the actual code.
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由 Rich Felker 提交于
at the point of call it was declared hidden, but the definition was not hidden. for some toolchains this inconsistency produced textrels without ld-time binding.
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由 Rich Felker 提交于
otherwise the call instruction in the inline syscall asm results in textrels without ld-time binding.
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