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libunwind-eh_elf/include/tdep-x86_64
Tim Deegan 4eb880e1b5 Implement DWARF DW_CFA_val_expression for x86_64
Ubuntu's libc-bin (2.15-0ubuntu20.2) on x86_64 uses DW_CFA_val_expression
in describing the pthread spinlock operations __lll_unlock_wake() and
__lll_lock_wait().  libunwind 1.1 doesn't understand that opcode and
so backtraces from those operations are truncated.

This changeset adds basic support for it, by adding a new type to
dwarf_loc_t that describes the register's actual contents rather than
its location.  I've only implemented the new type for x86_64, and
stubbed it out for all other architectures -- it looks like a lot
of that code is duplicated so oughtn't to be that hard, but I don't
have test cases for them.

Tested that DW_CFA_val_expression works on x86_64 (by using
https://code.google.com/p/gperftools/ on a lock-heavy program).
Build-tested on x86, x86_64 and arm.  The unit tests don't pass for me
on any of those archs, but this cset doesn't break anything that was
passing before.

Signed-off-by: Tim Deegan <tjd@phlegethon.org>
2014-02-08 20:19:20 -08:00
..
dwarf-config.h Handle register nums > 16 on x86_64 2011-06-18 20:48:49 -07:00
jmpbuf.h Remove extra empty line 2010-03-13 18:33:22 +02:00
libunwind_i.h Implement DWARF DW_CFA_val_expression for x86_64 2014-02-08 20:19:20 -08:00