| 1 | /* S/390-specific implementation of profiling support. |
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| 2 | Copyright (C) 2000-2024 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include <sysdep.h> |
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| 20 | |
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| 21 | /* |
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| 22 | * How profiling works on S/390: |
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| 23 | * On the start of each function _mcount is called with the address of a |
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| 24 | * data word in %r1 (initialized to 0, used for counting). The compiler |
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| 25 | * with the option -p generates code of the form: |
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| 26 | * |
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| 27 | * STM 6,15,24(15) |
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| 28 | * BRAS 13,.LTN0_0 |
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| 29 | * .LT0_0: |
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| 30 | * .LC12: .long _mcount |
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| 31 | * .LC13: .long .LP0 |
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| 32 | * .data |
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| 33 | * .align 4 |
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| 34 | * .LP0: .long 0 |
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| 35 | * .text |
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| 36 | * # function profiler |
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| 37 | * st 14,4(15) |
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| 38 | * l 14,.LC12-.LT0_0(13) |
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| 39 | * l 1,.LC13-.LT0_0(13) |
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| 40 | * basr 14,14 |
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| 41 | * l 14,4(15) |
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| 42 | * |
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| 43 | * The _mcount implementation now has to call __mcount_internal with the |
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| 44 | * address of .LP0 as first parameter and the return address as second |
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| 45 | * parameter. &.LP0 was loaded to %r1 and the return address is in %r14. |
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| 46 | * _mcount may not modify any register. |
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| 47 | */ |
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| 48 | |
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| 49 | .globl C_SYMBOL_NAME(_mcount) |
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| 50 | .type C_SYMBOL_NAME(_mcount), @function |
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| 51 | cfi_startproc |
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| 52 | .align ALIGNARG(4) |
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| 53 | C_LABEL(_mcount) |
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| 54 | /* Save the caller-clobbered registers. */ |
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| 55 | ahi %r15,-128 |
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| 56 | cfi_adjust_cfa_offset (128) |
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| 57 | /* binutils 2.28+: .cfi_val_offset r15, -96 */ |
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| 58 | .cfi_escape \ |
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| 59 | /* DW_CFA_val_offset */ 0x14, \ |
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| 60 | /* r15 */ 0x0f, \ |
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| 61 | /* scaled offset */ 0x18 |
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| 62 | stm %r14,%r5,96(%r15) |
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| 63 | cfi_offset (r14, -128) |
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| 64 | l %r2,132(%r15) # callers address = first parameter |
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| 65 | la %r2,0(%r2) # clear bit 0 |
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| 66 | la %r3,0(%r14) # callees address = second parameter |
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| 67 | |
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| 68 | #ifdef PIC |
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| 69 | bras %r14,0f |
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| 70 | .long _GLOBAL_OFFSET_TABLE_-. |
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| 71 | 0: al %r14,0(%r14) |
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| 72 | l %r14,__mcount_internal@GOT(%r14) |
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| 73 | #else |
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| 74 | bras %r14,0f |
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| 75 | .long __mcount_internal |
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| 76 | 0: l %r14,0(%r14) |
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| 77 | #endif |
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| 78 | basr %r14,%r14 |
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| 79 | |
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| 80 | /* |
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| 81 | * Pop the saved registers. Please note that `mcount' has no |
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| 82 | * return value. |
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| 83 | */ |
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| 84 | lm %r14,%r5,96(%r15) |
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| 85 | ahi %r15,128 |
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| 86 | cfi_adjust_cfa_offset (-128) |
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| 87 | br %r14 |
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| 88 | cfi_endproc |
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| 89 | ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount)) |
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| 90 | |
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| 91 | #undef mcount |
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| 92 | weak_alias (_mcount, mcount) |
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| 93 | |
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