diff options
Diffstat (limited to 'sysdeps/s390/s390-64/s390x-mcount.S')
| -rw-r--r-- | sysdeps/s390/s390-64/s390x-mcount.S | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/sysdeps/s390/s390-64/s390x-mcount.S b/sysdeps/s390/s390-64/s390x-mcount.S new file mode 100644 index 0000000000..831af9c552 --- /dev/null +++ b/sysdeps/s390/s390-64/s390x-mcount.S @@ -0,0 +1,72 @@ +/* 64 bit S/390-specific implemetation of profiling support. + Copyright (C) 2001 Free Software Foundation, Inc. + Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com) + 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <sysdep.h> + +/* How profiling works on 64 bit S/390: + On the start of each function _mcount is called with the address of a + data word in %r1 (initialized to 0, used for counting). The compiler + with the option -p generates code of the form: + + STM 6,15,24(15) + BRAS 13,.LTN0_0 + .LT0_0: + .LC13: .long .LP0 + .data + .align 4 + .LP0: .long 0 + .text + # function profiler + stg 14,4(15) + lg 1,.LC13-.LT0_0(13) + brasl 14,_mcount + lg 14,4(15) + + The _mcount implementation now has to call __mcount_internal with the + address of .LP0 as first parameter and the return address as second + parameter. &.LP0 was loaded to %r1 and the return address is in %r14. + _mcount may not modify any register. */ + + ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(_mcount) + ASM_TYPE_DIRECTIVE(C_SYMBOL_NAME(_mcount), @function) + .align ALIGNARG(4) +C_LABEL(_mcount) + /* Save the caller-clobbered registers. */ + aghi %r15,-224 + stmg %r14,%r5,160(%r15) + lg %r2,232(%r15) # callers address = first parameter + la %r2,0(%r2) # clear bit 0 + la %r3,0(%r14) # callees address = second parameter + +#ifdef PIC + brasl %r14,__mcount_internal@PLT +#else + brasl %r14,__mcount_internal +#endif + + /* Pop the saved registers. Please note that `mcount' has no + return value. */ + lmg %r14,%r5,160(%r15) + ahi %r15,224 + br %r14 + ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount)) + +#undef mcount +weak_alias(_mcount, mcount) |