1/* Machine-specific calling sequence for `mcount' profiling function.  ia64
2   Copyright (C) 2000-2021 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Lesser General Public
7   License as published by the Free Software Foundation; either
8   version 2.1 of the License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, see
17   <https://www.gnu.org/licenses/>.  */
18
19/* Assembly stub to invoke _mcount().  Compiler generated code calls
20   this stub before executing a function's prologue and without saving
21   any registers.  It is therefore necessary to preserve the input
22   registers as they may contain function arguments.  To work
23   correctly with frame-less functions, it is also necessary to
24   preserve the return pointer (b0 aka rp).
25
26   State upon entering _mcount:
27
28    r8  address of return value structure (used only when called
29	function returns a large structure)
30    r15 static link (used only for nested functions)
31    in0 ar.pfs to restore before returning to the function that
32	called _mcount
33    in1 gp value to restore before returning to the function that
34	called _mcount
35    in2 return address in the function that invoked the caller
36	of _mcount (frompc)
37    in3	address of the global-offset table entry that holds the
38	profile count dword allocated by the compiler; to get
39	the address of this dword, use "ld8 in2=[in2]; this
40	dword can be used in any way by _mcount (including
41	not at all, as is the case with the current implementation)
42    b0	address to return to after _mcount is done
43*/
44
45#include <sysdep.h>
46
47#undef ret
48
49LEAF(_mcount)
50	.prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(4)
51	alloc loc1 = ar.pfs, 4, 4, 3, 0
52	mov loc0 = rp
53	.body
54	mov loc2 = r8	// gcc uses r8 to pass pointer to return structure
55	;;
56	mov loc3 = r15	// gcc uses r15 to pass the static link to nested functions
57	mov out0 = in2
58	mov out1 = rp
59	br.call.sptk.few rp = __mcount
60	;;
61.here:
62{
63	.mii
64	mov gp = in1
65	mov r2 = ip
66	mov ar.pfs = loc1
67}
68	;;
69	adds r2 = _mcount_ret_helper - .here, r2
70	mov b7 = loc0
71	mov rp = in2
72	;;
73	mov r3 = in0
74	mov r8 = loc2
75	mov r15 = loc3
76	mov b6 = r2
77	br.ret.sptk.few b6
78END(_mcount)
79
80LOCAL_LEAF(_mcount_ret_helper)
81	.prologue
82	.altrp b7
83	.save ar.pfs, r3
84	.body
85	alloc r2 = ar.pfs, 0, 0, 8, 0
86	mov ar.pfs = r3
87	br b7
88END(_mcount_ret_helper)
89
90weak_alias (_mcount, mcount)
91