83 lines
2.7 KiB
C
83 lines
2.7 KiB
C
/* Copyright (C) 2011-2022 Free Software Foundation, Inc.
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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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<https://www.gnu.org/licenses/>. */
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#define _SYSDEPS_SYSDEP_H 1
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#include <bits/hwcap.h>
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#ifdef __ASSEMBLER__
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#define SPARC_PIC_THUNK(reg) \
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.ifndef __sparc_get_pc_thunk.reg; \
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.section .text.__sparc_get_pc_thunk.reg,"axG",@progbits,__sparc_get_pc_thunk.reg,comdat; \
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.align 32; \
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.weak __sparc_get_pc_thunk.reg; \
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.hidden __sparc_get_pc_thunk.reg; \
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.type __sparc_get_pc_thunk.reg, #function; \
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__sparc_get_pc_thunk.reg: \
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jmp %o7 + 8; \
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add %o7, %reg, %##reg; \
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.previous; \
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.endif;
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/* The "-4" and "+4" offsets against _GLOBAL_OFFSET_TABLE_ are
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critical since they represent the offset from the thunk call to the
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instruction containing the _GLOBAL_OFFSET_TABLE_ reference.
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Therefore these instructions cannot be moved around without
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appropriate adjustments to those offsets.
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Furthermore, these expressions are special in another regard. When
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the assembler sees a reference to _GLOBAL_OFFSET_TABLE_ inside of
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a %hi() or %lo(), it emits a PC-relative relocation. This causes
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R_SPARC_HI22 to turn into R_SPARC_PC22, and R_SPARC_LO10 to turn into
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R_SPARC_PC10, respectively.
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Even when v9 we use a call sequence instead of using "rd %pc" because
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RDPC is extremely expensive and incurs a full pipeline flush. */
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#define SPARC_PIC_THUNK_CALL(reg) \
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sethi %hi(_GLOBAL_OFFSET_TABLE_-4), %##reg; \
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call __sparc_get_pc_thunk.reg; \
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or %##reg, %lo(_GLOBAL_OFFSET_TABLE_+4), %##reg;
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#define SETUP_PIC_REG(reg) \
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SPARC_PIC_THUNK(reg) \
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SPARC_PIC_THUNK_CALL(reg)
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#define SETUP_PIC_REG_LEAF(reg, tmp) \
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SPARC_PIC_THUNK(reg) \
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mov %o7, %##tmp; \
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SPARC_PIC_THUNK_CALL(reg); \
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mov %##tmp, %o7;
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#undef ENTRY
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#define ENTRY(name) \
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.align 4; \
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.global C_SYMBOL_NAME(name); \
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.type name, @function; \
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C_LABEL(name) \
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cfi_startproc;
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#undef END
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#define END(name) \
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cfi_endproc; \
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.size name, . - name
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#undef LOC
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#define LOC(name) .L##name
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#endif /* __ASSEMBLER__ */
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