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267 lines
8.0 KiB
C++
267 lines
8.0 KiB
C++
/* Frame unwinder for frames with DWARF Call Frame Information.
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Copyright (C) 2003-2020 Free Software Foundation, Inc.
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Contributed by Mark Kettenis.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef DWARF2_FRAME_H
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#define DWARF2_FRAME_H 1
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struct gdbarch;
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struct objfile;
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struct frame_info;
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struct dwarf2_per_cu_data;
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struct agent_expr;
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struct axs_value;
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/* Register rule. */
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enum dwarf2_frame_reg_rule
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{
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/* Make certain that 0 maps onto the correct enum value; the
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corresponding structure is being initialized using memset zero.
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This indicates that CFI didn't provide any information at all
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about a register, leaving how to obtain its value totally
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unspecified. */
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DWARF2_FRAME_REG_UNSPECIFIED = 0,
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/* The term "undefined" comes from the DWARF2 CFI spec which this
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code is modeling; it indicates that the register's value is
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"undefined". GCC uses the less formal term "unsaved". Its
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definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
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The failure to differentiate the two helps explain a few problems
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with the CFI generated by GCC. */
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DWARF2_FRAME_REG_UNDEFINED,
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DWARF2_FRAME_REG_SAVED_OFFSET,
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DWARF2_FRAME_REG_SAVED_REG,
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DWARF2_FRAME_REG_SAVED_EXP,
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DWARF2_FRAME_REG_SAME_VALUE,
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/* These are defined in Dwarf3. */
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DWARF2_FRAME_REG_SAVED_VAL_OFFSET,
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DWARF2_FRAME_REG_SAVED_VAL_EXP,
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/* These aren't defined by the DWARF2 CFI specification, but are
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used internally by GDB. */
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DWARF2_FRAME_REG_FN, /* Call a registered function. */
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DWARF2_FRAME_REG_RA, /* Return Address. */
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DWARF2_FRAME_REG_RA_OFFSET, /* Return Address with offset. */
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DWARF2_FRAME_REG_CFA, /* Call Frame Address. */
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DWARF2_FRAME_REG_CFA_OFFSET /* Call Frame Address with offset. */
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};
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/* Register state. */
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struct dwarf2_frame_state_reg
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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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union {
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LONGEST offset;
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ULONGEST reg;
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struct
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{
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const gdb_byte *start;
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ULONGEST len;
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} exp;
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struct value *(*fn) (struct frame_info *this_frame, void **this_cache,
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int regnum);
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} loc;
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enum dwarf2_frame_reg_rule how;
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};
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enum cfa_how_kind
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{
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CFA_UNSET,
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CFA_REG_OFFSET,
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CFA_EXP
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};
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struct dwarf2_frame_state_reg_info
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{
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dwarf2_frame_state_reg_info () = default;
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~dwarf2_frame_state_reg_info ()
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{
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delete prev;
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}
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/* Copy constructor. */
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dwarf2_frame_state_reg_info (const dwarf2_frame_state_reg_info &src)
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: reg (src.reg), cfa_offset (src.cfa_offset),
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cfa_reg (src.cfa_reg), cfa_how (src.cfa_how), cfa_exp (src.cfa_exp),
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prev (src.prev)
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{
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}
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/* Assignment operator for both move-assignment and copy-assignment. */
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dwarf2_frame_state_reg_info&
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operator= (dwarf2_frame_state_reg_info rhs)
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{
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swap (*this, rhs);
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return *this;
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}
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/* Move constructor. */
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dwarf2_frame_state_reg_info (dwarf2_frame_state_reg_info &&rhs) noexcept
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: reg (std::move (rhs.reg)), cfa_offset (rhs.cfa_offset),
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cfa_reg (rhs.cfa_reg), cfa_how (rhs.cfa_how), cfa_exp (rhs.cfa_exp),
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prev (rhs.prev)
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{
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rhs.prev = nullptr;
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}
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/* If necessary, enlarge the register set to hold NUM_REGS_REQUESTED
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registers. */
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void alloc_regs (int num_regs_requested)
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{
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gdb_assert (num_regs_requested > 0);
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if (num_regs_requested <= reg.size ())
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return;
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reg.resize (num_regs_requested);
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}
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std::vector<struct dwarf2_frame_state_reg> reg;
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LONGEST cfa_offset = 0;
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ULONGEST cfa_reg = 0;
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enum cfa_how_kind cfa_how = CFA_UNSET;
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const gdb_byte *cfa_exp = NULL;
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/* Used to implement DW_CFA_remember_state. */
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struct dwarf2_frame_state_reg_info *prev = NULL;
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private:
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friend void swap (dwarf2_frame_state_reg_info& lhs,
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dwarf2_frame_state_reg_info& rhs)
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{
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using std::swap;
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swap (lhs.reg, rhs.reg);
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swap (lhs.cfa_offset, rhs.cfa_offset);
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swap (lhs.cfa_reg, rhs.cfa_reg);
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swap (lhs.cfa_how, rhs.cfa_how);
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swap (lhs.cfa_exp, rhs.cfa_exp);
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swap (lhs.prev, rhs.prev);
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}
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};
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struct dwarf2_cie;
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/* Structure describing a frame state. */
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struct dwarf2_frame_state
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{
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dwarf2_frame_state (CORE_ADDR pc, struct dwarf2_cie *cie);
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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 dwarf2_frame_state_reg_info regs {};
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/* The PC described by the current frame state. */
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CORE_ADDR pc;
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/* Initial register set from the CIE.
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Used to implement DW_CFA_restore. */
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struct dwarf2_frame_state_reg_info initial {};
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/* The information we care about from the CIE. */
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const LONGEST data_align;
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const ULONGEST code_align;
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const ULONGEST retaddr_column;
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/* Flags for known producer quirks. */
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/* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
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and DW_CFA_def_cfa_offset takes a factored offset. */
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bool armcc_cfa_offsets_sf = false;
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/* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
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the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
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bool armcc_cfa_offsets_reversed = false;
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};
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/* When this is true the DWARF frame unwinders can be used if they are
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registered with the gdbarch. Not all architectures can or do use the
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DWARF unwinders. Setting this to true on a target that does not
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otherwise support the DWARF unwinders has no effect. */
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extern bool dwarf2_frame_unwinders_enabled_p;
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/* Set the architecture-specific register state initialization
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function for GDBARCH to INIT_REG. */
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extern void dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
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void (*init_reg) (struct gdbarch *, int,
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struct dwarf2_frame_state_reg *,
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struct frame_info *));
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/* Set the architecture-specific signal trampoline recognition
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function for GDBARCH to SIGNAL_FRAME_P. */
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extern void
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dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
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int (*signal_frame_p) (struct gdbarch *,
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struct frame_info *));
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/* Set the architecture-specific adjustment of .eh_frame and .debug_frame
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register numbers. */
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extern void
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dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
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int (*adjust_regnum) (struct gdbarch *,
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int, int));
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/* Append the DWARF-2 frame unwinders to GDBARCH's list. */
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void dwarf2_append_unwinders (struct gdbarch *gdbarch);
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/* Return the frame base methods for the function that contains PC, or
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NULL if it can't be handled by the DWARF CFI frame unwinder. */
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extern const struct frame_base *
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dwarf2_frame_base_sniffer (struct frame_info *this_frame);
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/* Compute the DWARF CFA for a frame. */
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CORE_ADDR dwarf2_frame_cfa (struct frame_info *this_frame);
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/* Find the CFA information for PC.
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Return 1 if a register is used for the CFA, or 0 if another
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expression is used. Throw an exception on error.
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GDBARCH is the architecture to use.
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DATA is the per-CU data.
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REGNUM_OUT is an out parameter that is set to the register number.
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OFFSET_OUT is the offset to use from this register.
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These are only filled in when 1 is returned.
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TEXT_OFFSET_OUT, CFA_START_OUT, and CFA_END_OUT describe the CFA
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in other cases. These are only used when 0 is returned. */
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extern int dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
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struct dwarf2_per_cu_data *data,
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int *regnum_out, LONGEST *offset_out,
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CORE_ADDR *text_offset_out,
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const gdb_byte **cfa_start_out,
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const gdb_byte **cfa_end_out);
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#endif /* dwarf2-frame.h */
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