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Diffstat (limited to 'gdb/dwarf2/frame.h')
| -rw-r--r-- | gdb/dwarf2/frame.h | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/gdb/dwarf2/frame.h b/gdb/dwarf2/frame.h new file mode 100644 index 0000000..a0ec361 --- /dev/null +++ b/gdb/dwarf2/frame.h @@ -0,0 +1,266 @@ +/* Frame unwinder for frames with DWARF Call Frame Information. + + Copyright (C) 2003-2020 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 modeling; 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; + } + + /* Copy constructor. */ + dwarf2_frame_state_reg_info (const dwarf2_frame_state_reg_info &src) + : reg (src.reg), cfa_offset (src.cfa_offset), + cfa_reg (src.cfa_reg), cfa_how (src.cfa_how), cfa_exp (src.cfa_exp), + prev (src.prev) + { + } + + /* 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 (std::move (rhs.reg)), 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; + } + + /* If necessary, enlarge the register set to hold NUM_REGS_REQUESTED + registers. */ + void alloc_regs (int num_regs_requested) + { + gdb_assert (num_regs_requested > 0); + + if (num_regs_requested <= reg.size ()) + return; + + reg.resize (num_regs_requested); + } + + std::vector<struct dwarf2_frame_state_reg> reg; + + 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.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; +}; + +/* When this is true the DWARF frame unwinders can be used if they are + registered with the gdbarch. Not all architectures can or do use the + DWARF unwinders. Setting this to true on a target that does not + otherwise support the DWARF unwinders has no effect. */ +extern bool dwarf2_frame_unwinders_enabled_p; + +/* 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 */ |