1 // main.cc -- gold main function.
2 
3 // Copyright (C) 2006-2020 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
5 
6 // This file is part of gold.
7 
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
12 
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 // GNU General Public License for more details.
17 
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
22 
23 #include "gold.h"
24 
25 #include <cstdio>
26 #include <cstring>
27 
28 #ifdef HAVE_MALLINFO
29 #include <malloc.h>
30 #endif
31 
32 #include "libiberty.h"
33 
34 #include "script.h"
35 #include "options.h"
36 #include "target-select.h"
37 #include "parameters.h"
38 #include "errors.h"
39 #include "mapfile.h"
40 #include "dirsearch.h"
41 #include "workqueue.h"
42 #include "object.h"
43 #include "archive.h"
44 #include "symtab.h"
45 #include "layout.h"
46 #include "plugin.h"
47 #include "gc.h"
48 #include "icf.h"
49 #include "incremental.h"
50 #include "gdb-index.h"
51 #include "timer.h"
52 
53 using namespace gold;
54 
55 // This function emits the commandline to a hard-coded file in temp.
56 // This is useful for debugging since ld is typically invoked by gcc,
57 // so its commandline is not always easy to extract.  You should be
58 // able to run 'gcc -B... foo.o -o foo' to invoke this linker the
59 // first time, and then /tmp/ld-run-foo.sh to invoke it on subsequent
60 // runes.  "/tmp/ld-run-foo.sh debug" will run the linker inside gdb
61 // (or whatever value the environment variable GDB is set to), for
62 // even easier debugging.  Since this is a debugging-only tool, and
63 // creates files, it is only turned on when the user explicitly asks
64 // for it, by compiling with -DDEBUG.  Do not do this for release
65 // versions of the linker!
66 
67 #ifdef DEBUG
68 #include <stdio.h>
69 #include <sys/stat.h>    // for chmod()
70 
71 static std::string
72 collect_argv(int argc, char** argv)
73 {
74   // This is used by write_debug_script(), which wants the unedited argv.
75   std::string args;
76   for (int i = 0; i < argc; ++i)
77     {
78       args.append(" '");
79       // Now append argv[i], but with all single-quotes escaped
80       const char* argpos = argv[i];
81       while (1)
82         {
83           const int len = strcspn(argpos, "'");
84           args.append(argpos, len);
85           if (argpos[len] == '\0')
86             break;
87           args.append("'\"'\"'");
88           argpos += len + 1;
89         }
90       args.append("'");
91     }
92   return args;
93 }
94 
95 static void
96 write_debug_script(std::string filename_str,
97 		   const char* argv_0, const char* args)
98 {
99   size_t slash = filename_str.rfind('/');
100   if (slash != std::string::npos)
101     filename_str = filename_str.c_str() + slash + 1;
102   filename_str = std::string("/tmp/ld-run-") + filename_str + ".sh";
103   const char* filename = filename_str.c_str();
104   FILE* fp = fopen(filename, "w");
105   if (fp)
106     {
107       fprintf(fp, "[ \"$1\" = debug ]"
108               " && PREFIX=\"${GDB-gdb} --annotate=3 --fullname %s --args\""
109               " && shift\n",
110               argv_0);
111       fprintf(fp, "$PREFIX%s $*\n", args);
112       fclose(fp);
113       chmod(filename, 0755);
114     }
115   else
116     filename = "[none]";
117   fprintf(stderr, "Welcome to gold!  Commandline written to %s.\n", filename);
118   fflush(stderr);
119 }
120 
121 #else // !defined(DEBUG)
122 
123 static inline std::string
124 collect_argv(int, char**)
125 {
126   return "";
127 }
128 
129 static inline void
130 write_debug_script(std::string, const char*, const char*)
131 {
132 }
133 
134 #endif // !defined(DEBUG)
135 
136 
137 int
138 main(int argc, char** argv)
139 {
140 #if defined (HAVE_SETLOCALE) && defined (HAVE_LC_MESSAGES)
141   setlocale(LC_MESSAGES, "");
142 #endif
143 #if defined (HAVE_SETLOCALE)
144   setlocale(LC_CTYPE, "");
145 #endif
146   bindtextdomain(PACKAGE, LOCALEDIR);
147   textdomain(PACKAGE);
148 
149   program_name = argv[0];
150 
151   // In libiberty; expands @filename to the args in "filename".
152   expandargv(&argc, &argv);
153 
154   // This is used by write_debug_script(), which wants the unedited argv.
155   std::string args = collect_argv(argc, argv);
156 
157   Errors errors(program_name);
158 
159   // Initialize the global parameters, to let random code get to the
160   // errors object.
161   set_parameters_errors(&errors);
162 
163   // Handle the command line options.
164   Command_line command_line;
165   command_line.process(argc - 1, const_cast<const char**>(argv + 1));
166 
167   Timer timer;
168   if (command_line.options().stats())
169     {
170       timer.start();
171       set_parameters_timer(&timer);
172     }
173 
174   // Store some options in the globally accessible parameters.
175   set_parameters_options(&command_line.options());
176 
177   // Do this as early as possible (since it prints a welcome message).
178   write_debug_script(command_line.options().output_file_name(),
179                      program_name, args.c_str());
180 
181   // If the user asked for a map file, open it.
182   Mapfile* mapfile = NULL;
183   if (command_line.options().user_set_Map())
184     {
185       mapfile = new Mapfile();
186       if (!mapfile->open(command_line.options().Map()))
187 	{
188 	  delete mapfile;
189 	  mapfile = NULL;
190 	}
191     }
192 
193   // The GNU linker ignores version scripts when generating
194   // relocatable output.  If we are not compatible, then we break the
195   // Linux kernel build, which uses a linker script with -r which must
196   // not force symbols to be local.  It would actually be useful to
197   // permit symbols to be forced local with -r, though, as it would
198   // permit some linker optimizations.  Perhaps we need yet another
199   // option to control this.  FIXME.
200   if (parameters->options().relocatable())
201     command_line.script_options().version_script_info()->clear();
202 
203   // The work queue.
204   Workqueue workqueue(command_line.options());
205 
206   // The list of input objects.
207   Input_objects input_objects;
208 
209   // The Garbage Collection (GC, --gc-sections) Object.
210   Garbage_collection gc;
211 
212   // The Identical Code Folding (ICF, --icf) Object.
213   Icf icf;
214 
215   // The symbol table.  We're going to guess here how many symbols
216   // we're going to see based on the number of input files.  Even when
217   // this is off, it means at worst we don't quite optimize hashtable
218   // resizing as well as we could have (perhaps using more memory).
219   Symbol_table symtab(command_line.number_of_input_files() * 1024,
220                       command_line.version_script());
221 
222   if (parameters->options().gc_sections())
223     symtab.set_gc(&gc);
224 
225   if (parameters->options().icf_enabled())
226     symtab.set_icf(&icf);
227 
228   // The layout object.
229   Layout layout(command_line.number_of_input_files(),
230 		&command_line.script_options());
231 
232   if (layout.incremental_inputs() != NULL)
233     layout.incremental_inputs()->report_command_line(argc, argv);
234 
235   if (parameters->options().section_ordering_file())
236     layout.read_layout_from_file();
237 
238   // Load plugin libraries.
239   if (command_line.options().has_plugins())
240     command_line.options().plugins()->load_plugins(&layout);
241 
242   // Get the search path from the -L options.
243   Dirsearch search_path;
244   search_path.initialize(&workqueue, &command_line.options().library_path());
245 
246   // Queue up the first set of tasks.
247   queue_initial_tasks(command_line.options(), search_path,
248 		      command_line, &workqueue, &input_objects,
249 		      &symtab, &layout, mapfile);
250 
251   // Run the main task processing loop.
252   workqueue.process(0);
253 
254   if (command_line.options().print_output_format())
255     print_output_format();
256 
257   if (command_line.options().stats())
258     {
259       timer.stamp(2);
260       Timer::TimeStats elapsed = timer.get_pass_time(0);
261       fprintf(stderr,
262              _("%s: initial tasks run time: " \
263                "(user: %ld.%06ld sys: %ld.%06ld wall: %ld.%06ld)\n"),
264               program_name,
265               elapsed.user / 1000, (elapsed.user % 1000) * 1000,
266               elapsed.sys / 1000, (elapsed.sys % 1000) * 1000,
267               elapsed.wall / 1000, (elapsed.wall % 1000) * 1000);
268       elapsed = timer.get_pass_time(1);
269       fprintf(stderr,
270              _("%s: middle tasks run time: " \
271                "(user: %ld.%06ld sys: %ld.%06ld wall: %ld.%06ld)\n"),
272               program_name,
273               elapsed.user / 1000, (elapsed.user % 1000) * 1000,
274               elapsed.sys / 1000, (elapsed.sys % 1000) * 1000,
275               elapsed.wall / 1000, (elapsed.wall % 1000) * 1000);
276       elapsed = timer.get_pass_time(2);
277       fprintf(stderr,
278              _("%s: final tasks run time: " \
279                "(user: %ld.%06ld sys: %ld.%06ld wall: %ld.%06ld)\n"),
280               program_name,
281               elapsed.user / 1000, (elapsed.user % 1000) * 1000,
282               elapsed.sys / 1000, (elapsed.sys % 1000) * 1000,
283               elapsed.wall / 1000, (elapsed.wall % 1000) * 1000);
284       elapsed = timer.get_elapsed_time();
285       fprintf(stderr,
286              _("%s: total run time: " \
287                "(user: %ld.%06ld sys: %ld.%06ld wall: %ld.%06ld)\n"),
288               program_name,
289               elapsed.user / 1000, (elapsed.user % 1000) * 1000,
290               elapsed.sys / 1000, (elapsed.sys % 1000) * 1000,
291               elapsed.wall / 1000, (elapsed.wall % 1000) * 1000);
292 
293 #ifdef HAVE_MALLINFO
294       struct mallinfo m = mallinfo();
295       fprintf(stderr, _("%s: total space allocated by malloc: %lld bytes\n"),
296 	      program_name, static_cast<long long>(m.arena));
297 #endif
298       File_read::print_stats();
299       Archive::print_stats();
300       Lib_group::print_stats();
301       fprintf(stderr, _("%s: output file size: %lld bytes\n"),
302 	      program_name, static_cast<long long>(layout.output_file_size()));
303       symtab.print_stats();
304       layout.print_stats();
305       Gdb_index::print_stats();
306       Free_list::print_stats();
307     }
308 
309   // Issue defined symbol report.
310   if (command_line.options().user_set_print_symbol_counts())
311     input_objects.print_symbol_counts(&symtab);
312 
313   // Output cross reference table.
314   if (command_line.options().cref())
315     input_objects.print_cref(&symtab,
316 			     mapfile == NULL ? stdout : mapfile->file());
317 
318   if (mapfile != NULL)
319     mapfile->close();
320 
321   if (parameters->options().fatal_warnings()
322       && errors.warning_count() > 0
323       && errors.error_count() == 0)
324     gold_error("treating warnings as errors");
325 
326   // If the user used --noinhibit-exec, we force the exit status to be
327   // successful.  This is compatible with GNU ld.
328   gold_exit((errors.error_count() == 0
329 	     || parameters->options().noinhibit_exec())
330 	    ? GOLD_OK
331 	    : GOLD_ERR);
332 }
333