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(unw_init_local): Add comment as to why we can assume initial register window is

contiguous.

(Logical change 1.40)
This commit is contained in:
mostang.com!davidm 2003-01-21 17:41:20 +00:00
parent 3f3215952d
commit 644a56edfc

View file

@ -1,5 +1,5 @@
/* libunwind - a platform-independent unwind library /* libunwind - a platform-independent unwind library
Copyright (C) 2001-2002 Hewlett-Packard Co Copyright (C) 2001-2003 Hewlett-Packard Co
Contributed by David Mosberger-Tang <davidm@hpl.hp.com> Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
This file is part of libunwind. This file is part of libunwind.
@ -45,7 +45,6 @@ unw_init_local (unw_cursor_t *cursor, ucontext_t *uc)
{ {
struct cursor *c = (struct cursor *) cursor; struct cursor *c = (struct cursor *) cursor;
unw_word_t sol; unw_word_t sol;
int ret;
if (unw.needs_initialization) if (unw.needs_initialization)
{ {
@ -56,7 +55,11 @@ unw_init_local (unw_cursor_t *cursor, ucontext_t *uc)
/* The bsp value stored by getcontext() points to the *end* of the /* The bsp value stored by getcontext() points to the *end* of the
register frame of the initial function. We correct for this by register frame of the initial function. We correct for this by
storing the adjusted value in sc_rbs_base, which isn't used by storing the adjusted value in sc_rbs_base, which isn't used by
getcontext()/setcontext(). */ getcontext()/setcontext(). We can be certain that the entire
frame is stored in a contiguous rbs-area because the frame didn't
become part of the dirty partition until getcontext() was called
and we know that getcontext() doesn't switch the register-backing
store. */
sol = (uc->uc_mcontext.sc_ar_pfs >> 7) & 0x7f; sol = (uc->uc_mcontext.sc_ar_pfs >> 7) & 0x7f;
uc->uc_mcontext.sc_rbs_base = ia64_rse_skip_regs (uc->uc_mcontext.sc_ar_bsp, uc->uc_mcontext.sc_rbs_base = ia64_rse_skip_regs (uc->uc_mcontext.sc_ar_bsp,
-sol); -sol);