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Diffstat (limited to 'sysdeps/s390/s390-mcount.S')
| -rw-r--r-- | sysdeps/s390/s390-mcount.S | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/sysdeps/s390/s390-mcount.S b/sysdeps/s390/s390-mcount.S new file mode 100644 index 0000000000..e7c16b7052 --- /dev/null +++ b/sysdeps/s390/s390-mcount.S @@ -0,0 +1,84 @@ +/* S/390-specific implemetation of profiling support. + Copyright (C) 2000 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com) + + 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 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: + * .LC12: .long _mcount + * .LC13: .long .LP0 + * .data + * .align 4 + * .LP0: .long 0 + * .text + * # function profiler + * st 14,4(15) + * l 14,.LC12-.LT0_0(13) + * l 1,.LC13-.LT0_0(13) + * basr 14,14 + * l 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. */ + ahi %r15,-128 + stm %r14,%r5,96(%r15) + l %r2,132(%r15) # callers address = first parameter + la %r2,0(%r2) # clear bit 0 + la %r3,0(%r14) # callees address = second parameter + +#ifdef PIC + bras %r14,0f + .long _GLOBAL_OFFSET_TABLE_-. +0: al %r14,0(%r14) + l %r14,__mcount_internal@GOT(%r14) +#else + bras %r14,0f + .long __mcount_internal +0: l %r14,0(%r14) +#endif + basr %r14,%r14 + + /* + * Pop the saved registers. Please note that `mcount' has no + * return value. + */ + lm %r14,%r5,96(%r15) + ahi %r15,128 + br %r14 + ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount)) + +#undef mcount +weak_alias(_mcount, mcount) |