/* General Compile and inject code Copyright (C) 2014-2024 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 . */ #include "progspace.h" #include "ui.h" #include "ui-out.h" #include "command.h" #include "cli/cli-script.h" #include "cli/cli-utils.h" #include "cli/cli-option.h" #include "completer.h" #include "cli/cli-cmds.h" #include "compile.h" #include "compile-internal.h" #include "compile-object-load.h" #include "compile-object-run.h" #include "language.h" #include "frame.h" #include "source.h" #include "block.h" #include "arch-utils.h" #include "gdbsupport/filestuff.h" #include "target.h" #include "osabi.h" #include "gdbsupport/gdb_wait.h" #include "valprint.h" #include #include "gdbsupport/gdb_unlinker.h" #include "gdbsupport/pathstuff.h" #include "gdbsupport/scoped_ignore_signal.h" #include "gdbsupport/buildargv.h" /* Initial filename for temporary files. */ #define TMP_PREFIX "/tmp/gdbobj-" /* Hold "compile" commands. */ static struct cmd_list_element *compile_command_list; /* Debug flag for "compile" commands. */ bool compile_debug; /* See compile-internal.h. */ bool compile_instance::get_cached_type (struct type *type, gcc_type *ret) const { if (auto iter = m_type_map.find (type); iter != m_type_map.end ()) { *ret = iter->second; return true; } return false; } /* See compile-internal.h. */ void compile_instance::insert_type (struct type *type, gcc_type gcc_type) { auto [it, inserted] = m_type_map.emplace (type, gcc_type); /* The type might have already been inserted in order to handle recursive types. */ if (!inserted && it->second != gcc_type) error (_("Unexpected type id from GCC, check you use recent enough GCC.")); } /* See compile-internal.h. */ void compile_instance::insert_symbol_error (const struct symbol *sym, const char *text) { m_symbol_err_map.emplace (sym, text); } /* See compile-internal.h. */ void compile_instance::error_symbol_once (const struct symbol *sym) { if (auto iter = m_symbol_err_map.find (sym); iter != m_symbol_err_map.end () && !iter->second.empty ()) { std::string message = std::move (iter->second); error (_("%s"), message.c_str ()); } } /* Implement "show debug compile". */ static void show_compile_debug (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { gdb_printf (file, _("Compile debugging is %s.\n"), value); } /* Options for the compile command. */ struct compile_options { /* For -raw. */ bool raw = false; }; using compile_flag_option_def = gdb::option::flag_option_def; static const gdb::option::option_def compile_command_option_defs[] = { compile_flag_option_def { "raw", [] (compile_options *opts) { return &opts->raw; }, N_("Suppress automatic 'void _gdb_expr () { CODE }' wrapping."), }, }; /* Create an option_def_group for the "compile" command's options, with OPTS as context. */ static gdb::option::option_def_group make_compile_options_def_group (compile_options *opts) { return {{compile_command_option_defs}, opts}; } /* Handle the input from the 'compile file' command. The "compile file" command is used to evaluate an expression contained in a file that may contain calls to the GCC compiler. */ static void compile_file_command (const char *args, int from_tty) { scoped_restore save_async = make_scoped_restore (¤t_ui->async, 0); /* Check if a -raw option is provided. */ compile_options options; const gdb::option::option_def_group group = make_compile_options_def_group (&options); gdb::option::process_options (&args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, group); enum compile_i_scope_types scope = options.raw ? COMPILE_I_RAW_SCOPE : COMPILE_I_SIMPLE_SCOPE; std::string filename = extract_single_filename_arg (args); /* After processing options, check whether we have a filename. */ if (filename.empty ()) error (_("You must provide a filename for this command.")); std::string abspath = gdb_abspath (filename.c_str ()); std::string buffer = string_printf ("#include \"%s\"\n", abspath.c_str ()); eval_compile_command (NULL, buffer.c_str (), scope, NULL); } /* Completer for the "compile file" command. */ static void compile_file_command_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { const gdb::option::option_def_group group = make_compile_options_def_group (nullptr); if (gdb::option::complete_options (tracker, &text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, group)) return; word = advance_to_filename_maybe_quoted_complete_word_point (tracker, text); filename_maybe_quoted_completer (ignore, tracker, text, word); } /* Handle the input from the 'compile code' command. The "compile code" command is used to evaluate an expression that may contain calls to the GCC compiler. The language expected in this compile command is the language currently set in GDB. */ static void compile_code_command (const char *args, int from_tty) { scoped_restore save_async = make_scoped_restore (¤t_ui->async, 0); compile_options options; const gdb::option::option_def_group group = make_compile_options_def_group (&options); gdb::option::process_options (&args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, group); enum compile_i_scope_types scope = options.raw ? COMPILE_I_RAW_SCOPE : COMPILE_I_SIMPLE_SCOPE; if (args && *args) eval_compile_command (NULL, args, scope, NULL); else { counted_command_line l = get_command_line (compile_control, ""); l->control_u.compile.scope = scope; execute_control_command_untraced (l.get ()); } } /* Completer for the "compile code" command. */ static void compile_code_command_completer (struct cmd_list_element *ignore, completion_tracker &tracker, const char *text, const char *word) { const gdb::option::option_def_group group = make_compile_options_def_group (nullptr); if (gdb::option::complete_options (tracker, &text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR, group)) return; word = advance_to_expression_complete_word_point (tracker, text); symbol_completer (ignore, tracker, text, word); } /* Callback for compile_print_command. */ void compile_print_value (struct value *val, void *data_voidp) { const value_print_options *print_opts = (value_print_options *) data_voidp; print_value (val, *print_opts); } /* Handle the input from the 'compile print' command. The "compile print" command is used to evaluate and print an expression that may contain calls to the GCC compiler. The language expected in this compile command is the language currently set in GDB. */ static void compile_print_command (const char *arg, int from_tty) { enum compile_i_scope_types scope = COMPILE_I_PRINT_ADDRESS_SCOPE; value_print_options print_opts; scoped_restore save_async = make_scoped_restore (¤t_ui->async, 0); get_user_print_options (&print_opts); /* Override global settings with explicit options, if any. */ auto group = make_value_print_options_def_group (&print_opts); gdb::option::process_options (&arg, gdb::option::PROCESS_OPTIONS_REQUIRE_DELIMITER, group); print_command_parse_format (&arg, "compile print", &print_opts); /* Passing &PRINT_OPTS as SCOPE_DATA is safe as do_module_cleanup will not touch the stale pointer if compile_object_run has already quit. */ if (arg && *arg) eval_compile_command (NULL, arg, scope, &print_opts); else { counted_command_line l = get_command_line (compile_control, ""); l->control_u.compile.scope = scope; l->control_u.compile.scope_data = &print_opts; execute_control_command_untraced (l.get ()); } } /* Return the name of the temporary directory to use for .o files, and arrange for the directory to be removed at shutdown. */ static const char * get_compile_file_tempdir (void) { static char *tempdir_name; #define TEMPLATE TMP_PREFIX "XXXXXX" char tname[sizeof (TEMPLATE)]; if (tempdir_name != NULL) return tempdir_name; strcpy (tname, TEMPLATE); #undef TEMPLATE tempdir_name = mkdtemp (tname); if (tempdir_name == NULL) perror_with_name (_("Could not make temporary directory")); tempdir_name = xstrdup (tempdir_name); add_final_cleanup ([] () { char *zap; int wstat; gdb_assert (startswith (tempdir_name, TMP_PREFIX)); zap = concat ("rm -rf ", tempdir_name, (char *) NULL); wstat = system (zap); if (wstat == -1 || !WIFEXITED (wstat) || WEXITSTATUS (wstat) != 0) warning (_("Could not remove temporary directory %s"), tempdir_name); XDELETEVEC (zap); }); return tempdir_name; } /* Compute the names of source and object files to use. */ static compile_file_names get_new_file_names () { static int seq; const char *dir = get_compile_file_tempdir (); ++seq; return compile_file_names (string_printf ("%s%sout%d.c", dir, SLASH_STRING, seq), string_printf ("%s%sout%d.o", dir, SLASH_STRING, seq)); } /* Get the block and PC at which to evaluate an expression. */ static const struct block * get_expr_block_and_pc (CORE_ADDR *pc) { const struct block *block = get_selected_block (pc); if (block == NULL) { symtab_and_line cursal = get_current_source_symtab_and_line (current_program_space); if (cursal.symtab) block = cursal.symtab->compunit ()->blockvector ()->static_block (); if (block != NULL) *pc = block->entry_pc (); } else *pc = block->entry_pc (); return block; } /* String for 'set compile-args' and 'show compile-args'. */ static std::string compile_args = /* Override flags possibly coming from DW_AT_producer. */ "-O0 -gdwarf-4" /* We use -fPIE Otherwise GDB would need to reserve space large enough for any object file in the inferior in advance to get the final address when to link the object file to and additionally the default system linker script would need to be modified so that one can specify there the absolute target address. -fPIC is not used at is would require from GDB to generate .got. */ " -fPIE" /* We want warnings, except for some commonly happening for GDB commands. */ " -Wall " " -Wno-unused-but-set-variable" " -Wno-unused-variable" /* Override CU's possible -fstack-protector-strong. */ " -fno-stack-protector"; /* Parsed form of COMPILE_ARGS. */ static gdb_argv compile_args_argv; /* Implement 'set compile-args'. */ static void set_compile_args (const char *args, int from_tty, struct cmd_list_element *c) { compile_args_argv = gdb_argv (compile_args.c_str ()); } /* Implement 'show compile-args'. */ static void show_compile_args (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { gdb_printf (file, _("Compile command command-line arguments " "are \"%s\".\n"), value); } /* String for 'set compile-gcc' and 'show compile-gcc'. */ static std::string compile_gcc; /* Implement 'show compile-gcc'. */ static void show_compile_gcc (struct ui_file *file, int from_tty, struct cmd_list_element *c, const char *value) { gdb_printf (file, _("Compile command GCC driver filename is \"%s\".\n"), value); } /* Return DW_AT_producer parsed for get_selected_frame () (if any). Return NULL otherwise. GCC already filters its command-line arguments only for the suitable ones to put into DW_AT_producer - see GCC function gen_producer_string. */ static const char * get_selected_pc_producer_options (void) { CORE_ADDR pc = get_frame_pc (get_selected_frame (NULL)); struct compunit_symtab *symtab = find_pc_compunit_symtab (pc); const char *cs; if (symtab == NULL || symtab->producer () == NULL || !startswith (symtab->producer (), "GNU ")) return NULL; cs = symtab->producer (); while (*cs != 0 && *cs != '-') cs = skip_spaces (skip_to_space (cs)); if (*cs != '-') return NULL; return cs; } /* Filter out unwanted options from ARGV. */ static void filter_args (char **argv) { char **destv; for (destv = argv; *argv != NULL; argv++) { /* -fpreprocessed may get in commonly from ccache. */ if (strcmp (*argv, "-fpreprocessed") == 0) { xfree (*argv); continue; } *destv++ = *argv; } *destv = NULL; } /* Produce final vector of GCC compilation options. The first element of the combined argument vector are arguments relating to the target size ("-m64", "-m32" etc.). These are sourced from the inferior's architecture. The second element of the combined argument vector are arguments stored in the inferior DW_AT_producer section. If these are stored in the inferior (there is no guarantee that they are), they are added to the vector. The third element of the combined argument vector are argument supplied by the language implementation provided by compile-{lang}-support. These contain language specific arguments. The final element of the combined argument vector are arguments supplied by the "set compile-args" command. These are always appended last so as to override any of the arguments automatically generated above. */ static gdb_argv get_args (const compile_instance *compiler, struct gdbarch *gdbarch) { const char *cs_producer_options; gdb_argv result; std::string gcc_options = gdbarch_gcc_target_options (gdbarch); /* Make sure we have a non-empty set of options, otherwise GCC will error out trying to look for a filename that is an empty string. */ if (!gcc_options.empty ()) result = gdb_argv (gcc_options.c_str ()); cs_producer_options = get_selected_pc_producer_options (); if (cs_producer_options != NULL) { gdb_argv argv_producer (cs_producer_options); filter_args (argv_producer.get ()); result.append (std::move (argv_producer)); } result.append (gdb_argv (compiler->gcc_target_options ().c_str ())); result.append (compile_args_argv); return result; } /* A helper function suitable for use as the "print_callback" in the compiler object. */ static void print_callback (void *ignore, const char *message) { gdb_puts (message, gdb_stderr); } /* Process the compilation request. On success it returns the object and source file names. On an error condition, error () is called. */ static compile_file_names compile_to_object (struct command_line *cmd, const char *cmd_string, enum compile_i_scope_types scope) { const struct block *expr_block; CORE_ADDR trash_pc, expr_pc; int ok; struct gdbarch *gdbarch = get_current_arch (); std::string triplet_rx; if (!target_has_execution ()) error (_("The program must be running for the compile command to "\ "work.")); expr_block = get_expr_block_and_pc (&trash_pc); expr_pc = get_frame_address_in_block (get_selected_frame (NULL)); /* Set up instance and context for the compiler. */ std::unique_ptr compiler = current_language->get_compile_instance (); if (compiler == nullptr) error (_("No compiler support for language %s."), current_language->name ()); compiler->set_print_callback (print_callback, NULL); compiler->set_scope (scope); compiler->set_block (expr_block); /* From the provided expression, build a scope to pass to the compiler. */ string_file input_buf; const char *input; if (cmd != NULL) { struct command_line *iter; for (iter = cmd->body_list_0.get (); iter; iter = iter->next) { input_buf.puts (iter->line); input_buf.puts ("\n"); } input = input_buf.c_str (); } else if (cmd_string != NULL) input = cmd_string; else error (_("Neither a simple expression, or a multi-line specified.")); std::string code = current_language->compute_program (compiler.get (), input, gdbarch, expr_block, expr_pc); if (compile_debug) gdb_printf (gdb_stdlog, "debug output:\n\n%s", code.c_str ()); compiler->set_verbose (compile_debug); if (!compile_gcc.empty ()) { if (compiler->version () < GCC_FE_VERSION_1) error (_("Command 'set compile-gcc' requires GCC version 6 or higher " "(libcc1 interface version 1 or higher)")); compiler->set_driver_filename (compile_gcc.c_str ()); } else { const char *os_rx = osabi_triplet_regexp (gdbarch_osabi (gdbarch)); const char *arch_rx = gdbarch_gnu_triplet_regexp (gdbarch); /* Allow triplets with or without vendor set. */ triplet_rx = std::string (arch_rx) + "(-[^-]*)?-"; if (os_rx != nullptr) triplet_rx += os_rx; compiler->set_triplet_regexp (triplet_rx.c_str ()); } /* Set compiler command-line arguments. */ gdb_argv argv_holder = get_args (compiler.get (), gdbarch); int argc = argv_holder.count (); char **argv = argv_holder.get (); gdb::unique_xmalloc_ptr error_message = compiler->set_arguments (argc, argv, triplet_rx.c_str ()); if (error_message != NULL) error ("%s", error_message.get ()); if (compile_debug) { int argi; gdb_printf (gdb_stdlog, "Passing %d compiler options:\n", argc); for (argi = 0; argi < argc; argi++) gdb_printf (gdb_stdlog, "Compiler option %d: <%s>\n", argi, argv[argi]); } compile_file_names fnames = get_new_file_names (); std::optional source_remover; { gdb_file_up src = gdb_fopen_cloexec (fnames.source_file (), "w"); if (src == NULL) perror_with_name (_("Could not open source file for writing")); source_remover.emplace (fnames.source_file ()); if (fputs (code.c_str (), src.get ()) == EOF) perror_with_name (_("Could not write to source file")); } if (compile_debug) gdb_printf (gdb_stdlog, "source file produced: %s\n\n", fnames.source_file ()); /* If we don't do this, then GDB simply exits when the compiler dies. */ scoped_ignore_sigpipe ignore_sigpipe; /* Call the compiler and start the compilation process. */ compiler->set_source_file (fnames.source_file ()); ok = compiler->compile (fnames.object_file (), compile_debug); if (!ok) error (_("Compilation failed.")); if (compile_debug) gdb_printf (gdb_stdlog, "object file produced: %s\n\n", fnames.object_file ()); /* Keep the source file. */ source_remover->keep (); return fnames; } /* The "compile" prefix command. */ static void compile_command (const char *args, int from_tty) { /* If a sub-command is not specified to the compile prefix command, assume it is a direct code compilation. */ compile_code_command (args, from_tty); } /* See compile.h. */ void eval_compile_command (struct command_line *cmd, const char *cmd_string, enum compile_i_scope_types scope, void *scope_data) { compile_file_names fnames = compile_to_object (cmd, cmd_string, scope); gdb::unlinker object_remover (fnames.object_file ()); gdb::unlinker source_remover (fnames.source_file ()); compile_module_up compile_module = compile_object_load (fnames, scope, scope_data); if (compile_module == NULL) { gdb_assert (scope == COMPILE_I_PRINT_ADDRESS_SCOPE); eval_compile_command (cmd, cmd_string, COMPILE_I_PRINT_VALUE_SCOPE, scope_data); return; } /* Keep the files. */ source_remover.keep (); object_remover.keep (); compile_object_run (std::move (compile_module)); } /* See compile/compile-internal.h. */ std::string compile_register_name_mangled (struct gdbarch *gdbarch, int regnum) { const char *regname = gdbarch_register_name (gdbarch, regnum); return string_printf ("__%s", regname); } /* See compile/compile-internal.h. */ int compile_register_name_demangle (struct gdbarch *gdbarch, const char *regname) { int regnum; if (regname[0] != '_' || regname[1] != '_') error (_("Invalid register name \"%s\"."), regname); regname += 2; for (regnum = 0; regnum < gdbarch_num_regs (gdbarch); regnum++) if (strcmp (regname, gdbarch_register_name (gdbarch, regnum)) == 0) return regnum; error (_("Cannot find gdbarch register \"%s\"."), regname); } /* Forwards to the plug-in. */ #define FORWARD(OP,...) (m_gcc_fe->ops->OP (m_gcc_fe, ##__VA_ARGS__)) /* See compile-internal.h. */ void compile_instance::set_print_callback (void (*print_function) (void *, const char *), void *datum) { FORWARD (set_print_callback, print_function, datum); } /* See compile-internal.h. */ unsigned int compile_instance::version () const { return m_gcc_fe->ops->version; } /* See compile-internal.h. */ void compile_instance::set_verbose (int level) { if (version () >= GCC_FE_VERSION_1) FORWARD (set_verbose, level); } /* See compile-internal.h. */ void compile_instance::set_driver_filename (const char *filename) { if (version () >= GCC_FE_VERSION_1) FORWARD (set_driver_filename, filename); } /* See compile-internal.h. */ void compile_instance::set_triplet_regexp (const char *regexp) { if (version () >= GCC_FE_VERSION_1) FORWARD (set_triplet_regexp, regexp); } /* See compile-internal.h. */ gdb::unique_xmalloc_ptr compile_instance::set_arguments (int argc, char **argv, const char *regexp) { if (version () >= GCC_FE_VERSION_1) return gdb::unique_xmalloc_ptr (FORWARD (set_arguments, argc, argv)); else return gdb::unique_xmalloc_ptr (FORWARD (set_arguments_v0, regexp, argc, argv)); } /* See compile-internal.h. */ void compile_instance::set_source_file (const char *filename) { FORWARD (set_source_file, filename); } /* See compile-internal.h. */ bool compile_instance::compile (const char *filename, int verbose_level) { if (version () >= GCC_FE_VERSION_1) return FORWARD (compile, filename); else return FORWARD (compile_v0, filename, verbose_level); } #undef FORWARD /* See compile.h. */ cmd_list_element *compile_cmd_element = nullptr; void _initialize_compile (); void _initialize_compile () { struct cmd_list_element *c = NULL; compile_cmd_element = add_prefix_cmd ("compile", class_obscure, compile_command, _("\ Command to compile source code and inject it into the inferior."), &compile_command_list, 1, &cmdlist); add_com_alias ("expression", compile_cmd_element, class_obscure, 0); const auto compile_opts = make_compile_options_def_group (nullptr); static const std::string compile_code_help = gdb::option::build_help (_("\ Compile, inject, and execute code.\n\ \n\ Usage: compile code [OPTION]... [CODE]\n\ \n\ Options:\n\ %OPTIONS%\n\ \n\ The source code may be specified as a simple one line expression, e.g.:\n\ \n\ compile code printf(\"Hello world\\n\");\n\ \n\ Alternatively, you can type a multiline expression by invoking\n\ this command with no argument. GDB will then prompt for the\n\ expression interactively; type a line containing \"end\" to\n\ indicate the end of the expression."), compile_opts); c = add_cmd ("code", class_obscure, compile_code_command, compile_code_help.c_str (), &compile_command_list); set_cmd_completer_handle_brkchars (c, compile_code_command_completer); static const std::string compile_file_help = gdb::option::build_help (_("\ Evaluate a file containing source code.\n\ \n\ Usage: compile file [OPTION].. [FILENAME]\n\ \n\ Options:\n\ %OPTIONS%"), compile_opts); c = add_cmd ("file", class_obscure, compile_file_command, compile_file_help.c_str (), &compile_command_list); set_cmd_completer_handle_brkchars (c, compile_file_command_completer); const auto compile_print_opts = make_value_print_options_def_group (nullptr); static const std::string compile_print_help = gdb::option::build_help (_("\ Evaluate EXPR by using the compiler and print result.\n\ \n\ Usage: compile print [[OPTION]... --] [/FMT] [EXPR]\n\ \n\ Options:\n\ %OPTIONS%\n\ \n\ Note: because this command accepts arbitrary expressions, if you\n\ specify any command option, you must use a double dash (\"--\")\n\ to mark the end of option processing. E.g.: \"compile print -o -- myobj\".\n\ \n\ The expression may be specified on the same line as the command, e.g.:\n\ \n\ compile print i\n\ \n\ Alternatively, you can type a multiline expression by invoking\n\ this command with no argument. GDB will then prompt for the\n\ expression interactively; type a line containing \"end\" to\n\ indicate the end of the expression.\n\ \n\ EXPR may be preceded with /FMT, where FMT is a format letter\n\ but no count or size letter (see \"x\" command)."), compile_print_opts); c = add_cmd ("print", class_obscure, compile_print_command, compile_print_help.c_str (), &compile_command_list); set_cmd_completer_handle_brkchars (c, print_command_completer); add_setshow_boolean_cmd ("compile", class_maintenance, &compile_debug, _("\ Set compile command debugging."), _("\ Show compile command debugging."), _("\ When on, compile command debugging is enabled."), NULL, show_compile_debug, &setdebuglist, &showdebuglist); add_setshow_string_cmd ("compile-args", class_support, &compile_args, _("Set compile command GCC command-line arguments."), _("Show compile command GCC command-line arguments."), _("\ Use options like -I (include file directory) or ABI settings.\n\ String quoting is parsed like in shell, for example:\n\ -mno-align-double \"-I/dir with a space/include\""), set_compile_args, show_compile_args, &setlist, &showlist); /* Initialize compile_args_argv. */ set_compile_args (compile_args.c_str (), 0, NULL); add_setshow_optional_filename_cmd ("compile-gcc", class_support, &compile_gcc, _("Set compile command " "GCC driver filename."), _("Show compile command " "GCC driver filename."), _("\ It should be absolute filename of the gcc executable.\n\ If empty the default target triplet will be searched in $PATH."), NULL, show_compile_gcc, &setlist, &showlist); }