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/* Machine-specific calling sequence for `mcount' profiling function. ia64
Copyright (C) 2000-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Assembly stub to invoke _mcount(). Compiler generated code calls
this stub before executing a function's prologue and without saving
any registers. It is therefore necessary to preserve the input
registers as they may contain function arguments. To work
correctly with frame-less functions, it is also necessary to
preserve the return pointer (b0 aka rp).
State upon entering _mcount:
r8 address of return value structure (used only when called
function returns a large structure)
r15 static link (used only for nested functions)
in0 ar.pfs to restore before returning to the function that
called _mcount
in1 gp value to restore before returning to the function that
called _mcount
in2 return address in the function that invoked the caller
of _mcount (frompc)
in3 address of the global-offset table entry that holds the
profile count dword allocated by the compiler; to get
the address of this dword, use "ld8 in2=[in2]; this
dword can be used in any way by _mcount (including
not at all, as is the case with the current implementation)
b0 address to return to after _mcount is done
*/
#include <sysdep.h>
#undef ret
LEAF(_mcount)
.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(4)
alloc loc1 = ar.pfs, 4, 4, 3, 0
mov loc0 = rp
.body
mov loc2 = r8 // gcc uses r8 to pass pointer to return structure
;;
mov loc3 = r15 // gcc uses r15 to pass the static link to nested functions
mov out0 = in2
mov out1 = rp
br.call.sptk.few rp = __mcount
;;
.here:
{
.mii
mov gp = in1
mov r2 = ip
mov ar.pfs = loc1
}
;;
adds r2 = _mcount_ret_helper - .here, r2
mov b7 = loc0
mov rp = in2
;;
mov r3 = in0
mov r8 = loc2
mov r15 = loc3
mov b6 = r2
br.ret.sptk.few b6
END(_mcount)
LOCAL_LEAF(_mcount_ret_helper)
.prologue
.altrp b7
.save ar.pfs, r3
.body
alloc r2 = ar.pfs, 0, 0, 8, 0
mov ar.pfs = r3
br b7
END(_mcount_ret_helper)
weak_alias (_mcount, mcount)
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