binutils-gdb/gdb/exec.h
Simon Marchi 7831bc9185 gdb: remove get_exec_file
I believe that the get_exec_file function is unnecessary, and the code
can be simplified if we remove it.

Consider for instance when you "run" a program on Linux with native
debugging.

 1. run_command_1 obtains the executable file from
    `current_program_space->exec_filename ()`
 2. it passes it to `run_target->create_inferior()`, which is
    `inf_ptrace_target::create_inferior()` in this case, which then
    passes it to `fork_inferior()`
 3. `fork_inferior()` then has a fallback, where if the passed exec file
    is nullptr, it gets its from `get_exec_file()`.
 4. `get_exec_file()` returns `current_program_space->exec_filename ()`
    - just like the things we started with - or errors out if the
    current program space doesn't have a specified executable.

If there's no exec filename passed in step 1, there's not going to be
any in step 4, so it seems pointless to call `get_exec_file()`, we could
just error out when `exec_file` is nullptr.  But we can't error out
directly in `fork_inferior()`, since the error is GDB-specific, and that
function is shared with GDBserver.

Speaking of GDBserver, all code paths that lead to `fork_inferior()`
provide a non-nullptr exec file.

Therefore, to simplify things:

 - Make `fork_inferior()` assume that the passed exec file is not
   nullptr, don't call `get_exec_file()`
 - Change some targets (darwin-nat, go32-nat, gnu-nat, inf-ptrace,
   nto-procfs, procfs) to error out when the exec file passed to their
   create_inferior method is nullptr.  Some targets are fine with a
   nullptr exec file, so we can't check that in `run_command_1()`.
 - Add the `no_executable_specified_error()` function, which re-uses the
   error message that `get_exec_file()` had.
 - Change some targets (go32-nat, nto-procfs) to not call
   `get_exec_file()`, since it's pointless for the same reason as in the
   example above, if it returns, it's going the be the same value as the
   `exec_file` parameter.  Just rely on `exec_file`.
 - Remove the final use of `get_exec_file()`, in `load_command()`.
 - Remove the `get_exec_file()` implementations in GDB and GDBserver and
   remove the shared declaration.

Change-Id: I601c16498e455f7baa1f111a179da2f6c913baa3
Approved-By: Tom Tromey <tom@tromey.com>
2024-06-07 23:09:03 -04:00

114 lines
4.0 KiB
C++

/* Work with executable files, for GDB, the GNU debugger.
Copyright (C) 2003-2024 Free Software Foundation, Inc.
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 EXEC_H
#define EXEC_H
#include "target.h"
#include "progspace.h"
#include "memrange.h"
#include "symfile-add-flags.h"
struct target_section;
struct target_ops;
struct bfd;
struct objfile;
/* Builds a section table, given args BFD. */
extern std::vector<target_section> build_section_table (struct bfd *);
/* VFORK_CHILD is a child vforked and its program space is shared with its
parent. This pushes the exec target on that inferior's target stack if
there are sections in the program space's section table. */
extern void exec_on_vfork (inferior *vfork_child);
/* Read from mappable read-only sections of BFD executable files.
Return TARGET_XFER_OK, if read is successful. Return
TARGET_XFER_EOF if read is done. Return TARGET_XFER_E_IO
otherwise. */
extern enum target_xfer_status
exec_read_partial_read_only (gdb_byte *readbuf, ULONGEST offset,
ULONGEST len, ULONGEST *xfered_len);
/* Read or write from mappable sections of BFD executable files.
Request to transfer up to LEN 8-bit bytes of the target sections
defined by SECTIONS and SECTIONS_END. The OFFSET specifies the
starting address.
The MATCH_CB predicate is optional; when provided it will be called
for each section under consideration. When MATCH_CB evaluates as
true, the section remains under consideration; a false result
removes it from consideration for performing the memory transfers
noted above. See memory_xfer_partial_1() in target.c for an
example.
Return the number of bytes actually transfered, or zero when no
data is available for the requested range.
This function is intended to be used from target_xfer_partial
implementations. See target_read and target_write for more
information.
One, and only one, of readbuf or writebuf must be non-NULL. */
extern enum target_xfer_status
section_table_xfer_memory_partial (gdb_byte *,
const gdb_byte *,
ULONGEST, ULONGEST, ULONGEST *,
const std::vector<target_section> &,
gdb::function_view<bool
(const struct target_section *)> match_cb
= nullptr);
/* Read from mappable read-only sections of BFD executable files.
Similar to exec_read_partial_read_only, but return
TARGET_XFER_UNAVAILABLE if data is unavailable. */
extern enum target_xfer_status
section_table_read_available_memory (gdb_byte *readbuf, ULONGEST offset,
ULONGEST len, ULONGEST *xfered_len);
/* Set the loaded address of a section. */
extern void exec_set_section_address (const char *, int, CORE_ADDR);
/* Prints info about all sections defined in the TABLE. ABFD is
special cased --- it's filename is omitted; if it is the executable
file, its entry point is printed. */
extern void print_section_info (const std::vector<target_section> *table,
bfd *abfd);
/* Helper function that attempts to open the symbol file at EXEC_FILE_HOST.
If successful, it proceeds to add the symbol file as the main symbol file.
ADD_FLAGS is passed on to the function adding the symbol file. */
extern void try_open_exec_file (const char *exec_file_host,
struct inferior *inf,
symfile_add_flags add_flags);
/* Report a "No executable file specified" error. */
extern void no_executable_specified_error ();
#endif