binutils-gdb/gdb/dwarf2-frame.h

274 lines
8.2 KiB
C++

/* 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
{
dwarf2_frame_state_reg_info () = default;
~dwarf2_frame_state_reg_info ()
{
delete prev;
xfree (reg);
}
/* Copy constructor. */
dwarf2_frame_state_reg_info (const dwarf2_frame_state_reg_info &src)
: num_regs (src.num_regs), cfa_offset (src.cfa_offset),
cfa_reg (src.cfa_reg), cfa_how (src.cfa_how), cfa_exp (src.cfa_exp),
prev (src.prev)
{
size_t size = src.num_regs * sizeof (struct dwarf2_frame_state_reg);
reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
memcpy (reg, src.reg, size);
}
/* Assignment operator for both move-assignment and copy-assignment. */
dwarf2_frame_state_reg_info&
operator= (dwarf2_frame_state_reg_info rhs)
{
swap (*this, rhs);
return *this;
}
/* Move constructor. */
dwarf2_frame_state_reg_info (dwarf2_frame_state_reg_info &&rhs) noexcept
: reg (rhs.reg), num_regs (rhs.num_regs), cfa_offset (rhs.cfa_offset),
cfa_reg (rhs.cfa_reg), cfa_how (rhs.cfa_how), cfa_exp (rhs.cfa_exp),
prev (rhs.prev)
{
rhs.prev = nullptr;
rhs.reg = nullptr;
}
/* Assert that the register set RS is large enough to store gdbarch_num_regs
columns. If necessary, enlarge the register set. */
void alloc_regs (int num_regs_requested)
{
if (num_regs_requested <= num_regs)
return;
size_t size = sizeof (struct dwarf2_frame_state_reg);
reg = (struct dwarf2_frame_state_reg *)
xrealloc (reg, num_regs_requested * size);
/* Initialize newly allocated registers. */
memset (reg + num_regs, 0, (num_regs_requested - num_regs) * size);
num_regs = num_regs_requested;
}
struct dwarf2_frame_state_reg *reg = NULL;
int num_regs = 0;
LONGEST cfa_offset = 0;
ULONGEST cfa_reg = 0;
enum cfa_how_kind cfa_how = CFA_UNSET;
const gdb_byte *cfa_exp = NULL;
/* Used to implement DW_CFA_remember_state. */
struct dwarf2_frame_state_reg_info *prev = NULL;
private:
friend void swap (dwarf2_frame_state_reg_info& lhs,
dwarf2_frame_state_reg_info& rhs)
{
using std::swap;
swap (lhs.reg, rhs.reg);
swap (lhs.num_regs, rhs.num_regs);
swap (lhs.cfa_offset, rhs.cfa_offset);
swap (lhs.cfa_reg, rhs.cfa_reg);
swap (lhs.cfa_how, rhs.cfa_how);
swap (lhs.cfa_exp, rhs.cfa_exp);
swap (lhs.prev, rhs.prev);
}
};
struct dwarf2_cie;
/* Structure describing a frame state. */
struct dwarf2_frame_state
{
dwarf2_frame_state (CORE_ADDR pc, struct dwarf2_cie *cie);
/* 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. */
const LONGEST data_align;
const ULONGEST code_align;
const 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. */
bool armcc_cfa_offsets_sf = false;
/* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
bool armcc_cfa_offsets_reversed = false;
};
/* 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);
/* 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 */