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This patch provides a new handler MD_ARCH_FRAME_STATE_T to hide an architecture-specific structure containing CIE and FDE data related to DWARF architecture extensions. Hiding the architecture-specific attributes behind a handler has the following benefits: 1. isolating those data from the generic ones in _Unwind_FrameState 2. avoiding casts to custom types. 3. preserving typing information when debugging with GDB, and so facilitating their printing. This approach required to add a new header md-unwind-def.h included at the top of libgcc/unwind-dw2.h, and redirecting to the corresponding architecture header via a symbolic link. An obvious drawback is the increase in complexity with macros, and headers. It also caused a split of architecture definitions between md-unwind-def.h (types definitions used in unwind-dw2.h) and md-unwind.h (local types definitions and handlers implementations). The naming of md-unwind.h with .h extension is a bit misleading as the file is only included in the middle of unwind-dw2.c. Changing this naming would require modification of others backends, which I prefered to abstain from. Overall the benefits are worth the added complexity from my perspective. libgcc/ChangeLog: * Makefile.in: New target for symbolic link to md-unwind-def.h * config.host: New parameter md_unwind_def_header. Set it to aarch64/aarch64-unwind-def.h for AArch64 targets, or no-unwind.h by default. * config/aarch64/aarch64-unwind.h (aarch64_pointer_auth_key): Move to aarch64-unwind-def.h (aarch64_cie_aug_handler): Update. (aarch64_arch_extension_frame_init): Update. (aarch64_demangle_return_addr): Update. * configure.ac: New substitute variable md_unwind_def_header. * unwind-dw2.h (defined): MD_ARCH_FRAME_STATE_T. * config/aarch64/aarch64-unwind-def.h: New file. * configure: Regenerate. * config/no-unwind.h: Updated comment
96 lines
2.9 KiB
C
96 lines
2.9 KiB
C
/* DWARF2 frame unwind data structure.
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Copyright (C) 1997-2024 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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#include "md-unwind-def.h"
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enum register_rule
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{
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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_ARCHEXT, /* Target specific extension. */
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REG_UNDEFINED
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} __attribute__((packed));
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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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enum register_rule 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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/* Architecture extensions information from CIE/FDE.
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Note: this information has to be saved in struct frame_state_reg_info
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instead of _Unwind_FrameState as DW_CFA_restore_state has to be able to
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restore them. */
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#if defined(MD_ARCH_FRAME_STATE_T)
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MD_ARCH_FRAME_STATE_T arch_fs;
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#endif
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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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