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acdb24166d
On many architectures, there is a padding gap after the how array member, and cfa_how can be moved there. This reduces the size of the struct and the amount of memory that uw_frame_state_for has to clear. There is no measurable performance benefit from this on x86-64 (even though the memset goes from 120 to 112 bytes), but it seems to be a good idea to do anyway. libgcc/ * unwind-dw2.h (struct frame_state_reg_info): Move cfa_how member and reduce its size.
84 lines
2.5 KiB
C
84 lines
2.5 KiB
C
/* DWARF2 frame unwind data structure.
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Copyright (C) 1997-2022 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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enum {
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REG_UNSAVED,
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REG_SAVED_OFFSET,
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REG_SAVED_REG,
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REG_SAVED_EXP,
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REG_SAVED_VAL_OFFSET,
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REG_SAVED_VAL_EXP,
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REG_UNDEFINED
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};
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/* The result of interpreting the frame unwind info for a frame.
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This is all symbolic at this point, as none of the values can
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be resolved until the target pc is located. */
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typedef struct
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{
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/* Each register save state can be described in terms of a CFA slot,
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another register, or a location expression. */
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struct frame_state_reg_info
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{
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struct {
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union {
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_Unwind_Word reg;
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_Unwind_Sword offset;
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const unsigned char *exp;
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} loc;
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} reg[__LIBGCC_DWARF_FRAME_REGISTERS__+1];
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unsigned char how[__LIBGCC_DWARF_FRAME_REGISTERS__+1];
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enum {
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CFA_UNSET,
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CFA_REG_OFFSET,
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CFA_EXP
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} cfa_how : 8;
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/* Used to implement DW_CFA_remember_state. */
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struct frame_state_reg_info *prev;
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/* The CFA can be described in terms of a reg+offset or a
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location expression. */
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_Unwind_Sword cfa_offset;
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_Unwind_Word cfa_reg;
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const unsigned char *cfa_exp;
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} regs;
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/* The PC described by the current frame state. */
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void *pc;
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/* The information we care about from the CIE/FDE. */
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_Unwind_Personality_Fn personality;
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_Unwind_Sword data_align;
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_Unwind_Word code_align;
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_Unwind_Word retaddr_column;
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unsigned char fde_encoding;
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unsigned char lsda_encoding;
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unsigned char saw_z;
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unsigned char signal_frame;
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void *eh_ptr;
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} _Unwind_FrameState;
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