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/* Frame unwinder for frames with DWARF Call Frame Information.
Copyright (C) 2003-2017 Free Software Foundation, Inc.
Contributed by Mark Kettenis.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef DWARF2_FRAME_H
#define DWARF2_FRAME_H 1
struct gdbarch;
struct objfile;
struct frame_info;
struct dwarf2_per_cu_data;
struct agent_expr;
struct axs_value;
/* Register rule. */
enum dwarf2_frame_reg_rule
{
/* Make certain that 0 maps onto the correct enum value; the
corresponding structure is being initialized using memset zero.
This indicates that CFI didn't provide any information at all
about a register, leaving how to obtain its value totally
unspecified. */
DWARF2_FRAME_REG_UNSPECIFIED = 0,
/* The term "undefined" comes from the DWARF2 CFI spec which this
code is moddeling; it indicates that the register's value is
"undefined". GCC uses the less formal term "unsaved". Its
definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
The failure to differentiate the two helps explain a few problems
with the CFI generated by GCC. */
DWARF2_FRAME_REG_UNDEFINED,
DWARF2_FRAME_REG_SAVED_OFFSET,
DWARF2_FRAME_REG_SAVED_REG,
DWARF2_FRAME_REG_SAVED_EXP,
DWARF2_FRAME_REG_SAME_VALUE,
/* These are defined in Dwarf3. */
DWARF2_FRAME_REG_SAVED_VAL_OFFSET,
DWARF2_FRAME_REG_SAVED_VAL_EXP,
/* These aren't defined by the DWARF2 CFI specification, but are
used internally by GDB. */
DWARF2_FRAME_REG_FN, /* Call a registered function. */
DWARF2_FRAME_REG_RA, /* Return Address. */
DWARF2_FRAME_REG_RA_OFFSET, /* Return Address with offset. */
DWARF2_FRAME_REG_CFA, /* Call Frame Address. */
DWARF2_FRAME_REG_CFA_OFFSET /* Call Frame Address with offset. */
};
/* Register state. */
struct dwarf2_frame_state_reg
{
/* Each register save state can be described in terms of a CFA slot,
another register, or a location expression. */
union {
LONGEST offset;
ULONGEST reg;
struct
{
const gdb_byte *start;
ULONGEST len;
} exp;
struct value *(*fn) (struct frame_info *this_frame, void **this_cache,
int regnum);
} loc;
enum dwarf2_frame_reg_rule how;
};
enum cfa_how_kind
{
CFA_UNSET,
CFA_REG_OFFSET,
CFA_EXP
};
struct dwarf2_frame_state_reg_info
{
struct dwarf2_frame_state_reg *reg;
int num_regs;
LONGEST cfa_offset;
ULONGEST cfa_reg;
enum cfa_how_kind cfa_how;
const gdb_byte *cfa_exp;
/* Used to implement DW_CFA_remember_state. */
struct dwarf2_frame_state_reg_info *prev;
};
/* Structure describing a frame state. */
struct dwarf2_frame_state
{
/* Each register save state can be described in terms of a CFA slot,
another register, or a location expression. */
struct dwarf2_frame_state_reg_info regs;
/* The PC described by the current frame state. */
CORE_ADDR pc;
/* Initial register set from the CIE.
Used to implement DW_CFA_restore. */
struct dwarf2_frame_state_reg_info initial;
/* The information we care about from the CIE. */
LONGEST data_align;
ULONGEST code_align;
ULONGEST retaddr_column;
/* Flags for known producer quirks. */
/* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
and DW_CFA_def_cfa_offset takes a factored offset. */
int armcc_cfa_offsets_sf;
/* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
int armcc_cfa_offsets_reversed;
};
/* Set the architecture-specific register state initialization
function for GDBARCH to INIT_REG. */
extern void dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
void (*init_reg) (struct gdbarch *, int,
struct dwarf2_frame_state_reg *,
struct frame_info *));
/* Set the architecture-specific signal trampoline recognition
function for GDBARCH to SIGNAL_FRAME_P. */
extern void
dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
int (*signal_frame_p) (struct gdbarch *,
struct frame_info *));
/* Set the architecture-specific adjustment of .eh_frame and .debug_frame
register numbers. */
extern void
dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
int (*adjust_regnum) (struct gdbarch *,
int, int));
/* Append the DWARF-2 frame unwinders to GDBARCH's list. */
void dwarf2_append_unwinders (struct gdbarch *gdbarch);
/* Return the frame base methods for the function that contains PC, or
NULL if it can't be handled by the DWARF CFI frame unwinder. */
extern const struct frame_base *
dwarf2_frame_base_sniffer (struct frame_info *this_frame);
/* Compute the DWARF CFA for a frame. */
CORE_ADDR dwarf2_frame_cfa (struct frame_info *this_frame);
/* Assert that the register set RS is large enough to store gdbarch_num_regs
columns. If necessary, enlarge the register set. */
void dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
int num_regs);
/* Find the CFA information for PC.
Return 1 if a register is used for the CFA, or 0 if another
expression is used. Throw an exception on error.
GDBARCH is the architecture to use.
DATA is the per-CU data.
REGNUM_OUT is an out parameter that is set to the register number.
OFFSET_OUT is the offset to use from this register.
These are only filled in when 1 is returned.
TEXT_OFFSET_OUT, CFA_START_OUT, and CFA_END_OUT describe the CFA
in other cases. These are only used when 0 is returned. */
extern int dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
struct dwarf2_per_cu_data *data,
int *regnum_out, LONGEST *offset_out,
CORE_ADDR *text_offset_out,
const gdb_byte **cfa_start_out,
const gdb_byte **cfa_end_out);
#endif /* dwarf2-frame.h */
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