1d509aa625
With version 7.3 GCC supports new options
-mindirect-branch=<choice>
-mfunction-return=<choice>
The choices are:
keep behaves as before
thunk jumps through a thunk
thunk-external jumps through an external thunk
thunk-inline jumps through an inlined thunk
For thunk and thunk-external, GDB would, on a call to the thunk, step into
the thunk and then resume to its caller assuming that this is an
undebuggable function. On a return thunk, GDB would stop inside the
thunk.
Make GDB step through such thunks instead.
Before:
Temporary breakpoint 1, main ()
at gdb.base/step-indirect-call-thunk.c:37
37 x = apply (inc, 41);
(gdb) s
apply (op=0x80483e6 <inc>, x=41)
at gdb.base/step-indirect-call-thunk.c:29
29 return op (x);
(gdb)
30 }
After:
Temporary breakpoint 1, main ()
at gdb.base/step-indirect-call-thunk.c:37
37 x = apply (inc, 41);
(gdb) s
apply (op=0x80483e6 <inc>, x=41)
at gdb.base/step-indirect-call-thunk.c:29
29 return op (x);
(gdb)
inc (x=41) at gdb.base/step-indirect-call-thunk.c:23
23 return x + 1;
This is independent of the step-mode. In order to step into the thunk,
you would need to use stepi.
When stepping over an indirect call thunk, GDB would first step through
the thunk, then recognize that it stepped into a sub-routine and resume to
the caller (of the thunk). Not sure whether this is worth optimizing.
Thunk detection is implemented via gdbarch. I implemented the methods for
IA. Other architectures may run into unexpected fails.
The tests assume a fixed number of instruction steps to reach a thunk.
This depends on the compiler as well as the architecture. They may need
adjustments when we add support for more architectures. Or we can simply
drop those tests that cover being able to step into thunks using
instruction stepping.
When using an older GCC, the tests will fail to build and will be reported
as untested:
Running .../gdb.base/step-indirect-call-thunk.exp ...
gdb compile failed, \
gcc: error: unrecognized command line option '-mindirect-branch=thunk'
gcc: error: unrecognized command line option '-mfunction-return=thunk'
=== gdb Summary ===
# of untested testcases 1
gdb/
* infrun.c (process_event_stop_test): Call
gdbarch_in_indirect_branch_thunk.
* gdbarch.sh (in_indirect_branch_thunk): New.
* gdbarch.c: Regenerated.
* gdbarch.h: Regenerated.
* x86-tdep.h: New.
* x86-tdep.c: New.
* Makefile.in (ALL_TARGET_OBS): Add x86-tdep.o.
(HFILES_NO_SRCDIR): Add x86-tdep.h.
(ALLDEPFILES): Add x86-tdep.c.
* arch-utils.h (default_in_indirect_branch_thunk): New.
* arch-utils.c (default_in_indirect_branch_thunk): New.
* i386-tdep: Include x86-tdep.h.
(i386_in_indirect_branch_thunk): New.
(i386_elf_init_abi): Set in_indirect_branch_thunk gdbarch
function.
* amd64-tdep: Include x86-tdep.h.
(amd64_in_indirect_branch_thunk): New.
(amd64_init_abi): Set in_indirect_branch_thunk gdbarch function.
testsuite/
* gdb.base/step-indirect-call-thunk.exp: New.
* gdb.base/step-indirect-call-thunk.c: New.
* gdb.reverse/step-indirect-call-thunk.exp: New.
* gdb.reverse/step-indirect-call-thunk.c: New.
271 lines
9.4 KiB
C++
271 lines
9.4 KiB
C++
/* Dynamic architecture support for GDB, the GNU debugger.
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Copyright (C) 1998-2018 Free Software Foundation, Inc.
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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 GDBARCH_UTILS_H
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#define GDBARCH_UTILS_H
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struct gdbarch;
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struct frame_info;
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struct minimal_symbol;
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struct type;
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struct gdbarch_info;
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struct dwarf2_frame_state;
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template <size_t bp_size, const gdb_byte *break_insn>
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struct bp_manipulation
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{
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static int
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kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
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{
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return bp_size;
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}
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static const gdb_byte *
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bp_from_kind (struct gdbarch *gdbarch, int kind, int *size)
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{
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*size = kind;
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return break_insn;
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}
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};
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template <size_t bp_size,
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const gdb_byte *break_insn_little,
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const gdb_byte *break_insn_big>
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struct bp_manipulation_endian
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{
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static int
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kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
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{
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return bp_size;
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}
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static const gdb_byte *
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bp_from_kind (struct gdbarch *gdbarch, int kind, int *size)
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{
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*size = kind;
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if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG)
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return break_insn_big;
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else
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return break_insn_little;
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}
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};
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#define BP_MANIPULATION(BREAK_INSN) \
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bp_manipulation<sizeof (BREAK_INSN), BREAK_INSN>
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#define BP_MANIPULATION_ENDIAN(BREAK_INSN_LITTLE, BREAK_INSN_BIG) \
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bp_manipulation_endian<sizeof (BREAK_INSN_LITTLE), \
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BREAK_INSN_LITTLE, BREAK_INSN_BIG>
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/* Default implementation of gdbarch_displaced_hw_singlestep. */
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extern int
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default_displaced_step_hw_singlestep (struct gdbarch *,
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struct displaced_step_closure *);
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/* Possible value for gdbarch_displaced_step_location:
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Place displaced instructions at the program's entry point,
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leaving space for inferior function call return breakpoints. */
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extern CORE_ADDR displaced_step_at_entry_point (struct gdbarch *gdbarch);
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/* The only possible cases for inner_than. */
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extern int core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs);
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extern int core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs);
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/* Identity functions on a CORE_ADDR. Just return the "addr". */
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extern CORE_ADDR core_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr);
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extern gdbarch_convert_from_func_ptr_addr_ftype convert_from_func_ptr_addr_identity;
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/* No-op conversion of reg to regnum. */
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extern int no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg);
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/* Do nothing version of coff_make_msymbol_special. */
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void default_coff_make_msymbol_special (int val, struct minimal_symbol *msym);
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/* Do nothing default implementation of gdbarch_make_symbol_special. */
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void default_make_symbol_special (struct symbol *sym, struct objfile *objfile);
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/* Do nothing default implementation of gdbarch_adjust_dwarf2_addr. */
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CORE_ADDR default_adjust_dwarf2_addr (CORE_ADDR pc);
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/* Do nothing default implementation of gdbarch_adjust_dwarf2_line. */
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CORE_ADDR default_adjust_dwarf2_line (CORE_ADDR addr, int rel);
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/* Default DWARF vendor CFI handler. */
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bool default_execute_dwarf_cfa_vendor_op (struct gdbarch *gdbarch, gdb_byte op,
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struct dwarf2_frame_state *fs);
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/* Version of cannot_fetch_register() / cannot_store_register() that
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always fails. */
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int cannot_register_not (struct gdbarch *gdbarch, int regnum);
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/* Legacy version of target_virtual_frame_pointer(). Assumes that
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there is an gdbarch_deprecated_fp_regnum and that it is the same, cooked or
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raw. */
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extern gdbarch_virtual_frame_pointer_ftype legacy_virtual_frame_pointer;
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/* Default implementation of gdbarch_floatformat_for_type. */
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extern const struct floatformat **
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default_floatformat_for_type (struct gdbarch *gdbarch,
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const char *name, int len);
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extern CORE_ADDR generic_skip_trampoline_code (struct frame_info *frame,
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CORE_ADDR pc);
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extern CORE_ADDR generic_skip_solib_resolver (struct gdbarch *gdbarch,
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CORE_ADDR pc);
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extern int generic_in_solib_return_trampoline (struct gdbarch *gdbarch,
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CORE_ADDR pc, const char *name);
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extern int generic_stack_frame_destroyed_p (struct gdbarch *gdbarch,
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CORE_ADDR pc);
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extern int default_code_of_frame_writable (struct gdbarch *gdbarch,
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struct frame_info *frame);
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/* By default, registers are not convertible. */
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extern int generic_convert_register_p (struct gdbarch *gdbarch, int regnum,
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struct type *type);
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extern int default_stabs_argument_has_addr (struct gdbarch *gdbarch,
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struct type *type);
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extern int generic_instruction_nullified (struct gdbarch *gdbarch,
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struct regcache *regcache);
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int default_remote_register_number (struct gdbarch *gdbarch,
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int regno);
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/* For compatibility with older architectures, returns
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(LEGACY_SIM_REGNO_IGNORE) when the register doesn't have a valid
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name. */
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extern int legacy_register_sim_regno (struct gdbarch *gdbarch, int regnum);
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/* Return the selected byte order, or BFD_ENDIAN_UNKNOWN if no byte
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order was explicitly selected. */
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extern enum bfd_endian selected_byte_order (void);
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/* Return the selected architecture's name, or NULL if no architecture
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was explicitly selected. */
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extern const char *selected_architecture_name (void);
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/* Initialize a ``struct info''. Can't use memset(0) since some
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default values are not zero. "fill" takes all available
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information and fills in any unspecified fields. */
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extern void gdbarch_info_init (struct gdbarch_info *info);
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/* Similar to init, but this time fill in the blanks. Information is
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obtained from the global "set ..." options and explicitly
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initialized INFO fields. */
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extern void gdbarch_info_fill (struct gdbarch_info *info);
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/* Return the architecture for ABFD. If no suitable architecture
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could be find, return NULL. */
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extern struct gdbarch *gdbarch_from_bfd (bfd *abfd);
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/* Return "current" architecture. If the target is running, this is the
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architecture of the selected frame. Otherwise, the "current" architecture
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defaults to the target architecture.
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This function should normally be called solely by the command interpreter
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routines to determine the architecture to execute a command in. */
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extern struct gdbarch *get_current_arch (void);
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extern int default_has_shared_address_space (struct gdbarch *);
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extern int default_fast_tracepoint_valid_at (struct gdbarch *gdbarch,
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CORE_ADDR addr, std::string *msg);
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extern const gdb_byte *default_breakpoint_from_pc (struct gdbarch *gdbarch,
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CORE_ADDR *pcptr,
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int *lenptr);
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extern int default_breakpoint_kind_from_current_state (struct gdbarch *gdbarch,
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struct regcache *regcache,
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CORE_ADDR *pcptr);
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extern void default_gen_return_address (struct gdbarch *gdbarch,
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struct agent_expr *ax,
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struct axs_value *value,
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CORE_ADDR scope);
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extern const char *default_auto_charset (void);
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extern const char *default_auto_wide_charset (void);
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extern int default_return_in_first_hidden_param_p (struct gdbarch *,
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struct type *);
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extern int default_insn_is_call (struct gdbarch *, CORE_ADDR);
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extern int default_insn_is_ret (struct gdbarch *, CORE_ADDR);
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extern int default_insn_is_jump (struct gdbarch *, CORE_ADDR);
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/* Do-nothing version of vsyscall_range. Returns false. */
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extern int default_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range);
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/* Default way to advance the PC to the next instruction in order to
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skip a permanent breakpoint. Increments the PC by the size of a
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software breakpoint instruction, as determined with
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gdbarch_breakpoint_from_pc. This matches how the breakpoints
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module determines whether a breakpoint is permanent. */
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extern void default_skip_permanent_breakpoint (struct regcache *regcache);
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/* Symbols for gdbarch_infcall_mmap; their Linux PROT_* system
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definitions would be dependent on compilation host. */
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#define GDB_MMAP_PROT_READ 0x1 /* Page can be read. */
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#define GDB_MMAP_PROT_WRITE 0x2 /* Page can be written. */
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#define GDB_MMAP_PROT_EXEC 0x4 /* Page can be executed. */
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extern CORE_ADDR default_infcall_mmap (CORE_ADDR size, unsigned prot);
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extern void default_infcall_munmap (CORE_ADDR addr, CORE_ADDR size);
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extern char *default_gcc_target_options (struct gdbarch *gdbarch);
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extern const char *default_gnu_triplet_regexp (struct gdbarch *gdbarch);
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extern int default_addressable_memory_unit_size (struct gdbarch *gdbarch);
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extern void default_guess_tracepoint_registers (struct gdbarch *gdbarch,
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struct regcache *regcache,
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CORE_ADDR addr);
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extern int default_print_insn (bfd_vma memaddr, disassemble_info *info);
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/* Wrapper to gdbarch_skip_prologue, but doesn't throw exception. Catch
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exception thrown from gdbarch_skip_prologue, and return PC. */
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extern CORE_ADDR gdbarch_skip_prologue_noexcept (gdbarch *gdbarch,
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CORE_ADDR pc) noexcept;
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/* Default implementation of gdbarch_in_indirect_branch_thunk that returns
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false. */
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extern bool default_in_indirect_branch_thunk (gdbarch *gdbarch,
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CORE_ADDR pc);
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#endif
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