/* Frame unwinder for frames with DWARF Call Frame Information. Copyright (C) 2003-2018 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 */