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https://github.com/tobast/libunwind-eh_elf.git
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86 lines
4.1 KiB
Text
86 lines
4.1 KiB
Text
- implement non-local versions of dwarf_readXX()
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- document new "tdep" member in unw_proc_info_t structure
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- for DWARF 2, use a dummy CIE entry with an augmentation that
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provides the dyn-info-list-address
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- caching is pretty fundamentally broken, what should happen is this:
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o On unw_init_local()/unw_init_remote(), libunwind should validate
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that the cached information is still valid and, if not, flush the
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cache on its own. Rational: once unw_init_local() has been
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called, it is clear that the unwind info for the calling thread
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cannot change (otherwise the program would be buggy anyhow) and
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hence it is sufficient to validate the cache at this point.
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Similarly, once unw_init_remote() has been called, the target
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address space must have been stopped, because the unwinding would
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otherwise be unreliable anyhow.
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o glibc currently lacks a feature for dl_iterate_phdr() to support
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safe caching; I proposed on 12/16/2003 that glibc maintain two
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atomic counters which get inremented whenever something is added
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to/removed from the dl_iterate_phdr-list. Once we have such counters,
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we can use them in libunwind to implement an efficient version of a
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cache-validation routine.
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Once this has been fixed, update the libunwind man page accordingly.
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Effectively, what this means is that unw_flush_cache() doesn't have
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to be called by applications except for extraordinary circumstances
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(e.g., if application implements its own runtime loader).
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Testing:
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- ensure that saving r4-r7 in a stacked register properly preserves
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the NaT bit, even in the face of register-rotation
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- ensure that IA64_INSN_MOVE_STACKED works correctly in the face of
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register rotation
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- on Linux, test access to f32-f127 in a signal handler (e.g., verify
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that fph partition gets initialized properly)
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=== taken care of:
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+ man-page for unw_is_fpreg()
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+ man-page for _U_dyn_cancel()
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+ man-page for _U_dyn_register()
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+ global data is not protected by a lock; causes problems if two threads
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call ia64_init() at almost the same time
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+ cache the value of *cfm_loc; each rotate_FOO() call needs it!
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+ implement the remote-lookup of the dynamic registration list
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+ when doing sigreturn, must restore fp regs (and perhaps other regs) the same
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way as the (user-level) gate.S sigreturn path does!
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+ unw_resume() must at least restore gp (r1)! consider restoring all
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scratch regs (but what's the performance impact on exception handling?);
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alternative: restore scratch regs that may be used during procedure
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call/return (e.g., r8-r11, f8-f11)
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+ implement unw_resume() for the case where the current register frame is split
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across multiple backing stores
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+ document restricions on using unw_resume():
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+ implement remote cases of unw_resume()
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+ test both with UNW_LOCAL_ONLY and without where this makes sense
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+ allow region-length (insn_count) in unw_dyn_region_info_t to be negative
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to indicate counting from the end of the procedure (to make it possible
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for differently-sized procedures to share the same region list if they
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share the same prologue/epilogue).
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+ it appears that it is currently not possible to read register UNW_IA64_TP;
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fix that => no, attempts to access r13 will result in access_reg() callbacks,
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as desired; for local-case, access to r13 will fail though (since
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getcontext() doesn't, and shouldn't, capture r13)
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+ document the special nature of UNW_IA64_GP: read-only, but adjusted
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automatically if the IP is changed
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+ use pthread-mutexes where necessary, atomic ops where possible
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+ man-page for unw_init_local()
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+ man-page for unw_init_remote()
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+ man-page for unw_create_addr_space()
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+ man-page for unw_destroy_addr_space()
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+ man-page for unw_get_proc_info()
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+ man-page for unw_get_proc_name()
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+ man-page for unw_get_accessors()
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+ man-page for unw_regname()
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+ man-page for unw_flush_cache()
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+ man-page for unw_set_caching_policy()
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+ man-page for unw_getcontext()
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+ man-page for unw_is_signal_frame()
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+ man-page for unw_step()
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+ man-page for unw_get_reg()
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+ man-page for unw_set_reg()
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+ man-page for unw_get_fpreg()
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+ man-page for unw_set_fpreg()
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+ test with Intel compiler
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