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78 lines
2.5 KiB
ArmAsm
78 lines
2.5 KiB
ArmAsm
/* 64 bit S/390-specific implementation of profiling support.
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Copyright (C) 2001-2017 Free Software Foundation, Inc.
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Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com)
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdep.h>
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/* How profiling works on 64 bit S/390:
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On the start of each function _mcount is called with the address of a
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data word in %r1 (initialized to 0, used for counting). The compiler
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with the option -p generates code of the form:
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STM 6,15,24(15)
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BRAS 13,.LTN0_0
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.LT0_0:
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.LC13: .long .LP0
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.data
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.align 4
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.LP0: .long 0
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.text
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# function profiler
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stg 14,4(15)
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lg 1,.LC13-.LT0_0(13)
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brasl 14,_mcount
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lg 14,4(15)
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The _mcount implementation now has to call __mcount_internal with the
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address of .LP0 as first parameter and the return address as second
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parameter. &.LP0 was loaded to %r1 and the return address is in %r14.
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_mcount may not modify any register. */
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.globl C_SYMBOL_NAME(_mcount)
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.type C_SYMBOL_NAME(_mcount), @function
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cfi_startproc
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.align ALIGNARG(4)
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C_LABEL(_mcount)
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/* Save the caller-clobbered registers. */
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aghi %r15,-224
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cfi_adjust_cfa_offset (224)
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stmg %r14,%r5,160(%r15)
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cfi_offset (r14, 0)
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cfi_offset (r15, 8)
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lg %r2,232(%r15) # callers address = first parameter
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la %r2,0(%r2) # clear bit 0
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la %r3,0(%r14) # callees address = second parameter
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#ifdef PIC
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brasl %r14,__mcount_internal@PLT
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#else
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brasl %r14,__mcount_internal
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#endif
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/* Pop the saved registers. Please note that `mcount' has no
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return value. */
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lmg %r14,%r5,160(%r15)
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aghi %r15,224
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cfi_adjust_cfa_offset (-224)
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br %r14
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cfi_endproc
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ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount))
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#undef mcount
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weak_alias (_mcount, mcount)
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