1/* Specific flags and argument handling of the C++ front end.
2 Copyright (C) 1996-2025 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify
7it under the terms of the GNU General Public License as published by
8the Free Software Foundation; either version 3, or (at your option)
9any later version.
10
11GCC is distributed in the hope that it will be useful,
12but WITHOUT ANY WARRANTY; without even the implied warranty of
13MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14GNU General Public License for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#include "config.h"
21#include "system.h"
22#include "coretypes.h"
23#include "tm.h"
24#include "opts.h"
25
26/* This bit is set if we saw a `-xfoo' language specification. */
27#define LANGSPEC (1<<1)
28/* This bit is set if they did `-lm' or `-lmath'. */
29#define MATHLIB (1<<2)
30/* This bit is set if they did `-lc'. */
31#define WITHLIBC (1<<3)
32/* Skip this option. */
33#define SKIPOPT (1<<4)
34/* Add -lstdc++exp for experimental features that need library support. */
35#define EXPERIMENTAL (1<<5)
36
37#ifndef MATH_LIBRARY
38#define MATH_LIBRARY "m"
39#endif
40#ifndef MATH_LIBRARY_PROFILE
41#define MATH_LIBRARY_PROFILE MATH_LIBRARY
42#endif
43
44#ifndef LIBSTDCXX
45#define LIBSTDCXX "stdc++"
46#endif
47#ifndef LIBSTDCXX_PROFILE
48#define LIBSTDCXX_PROFILE LIBSTDCXX
49#endif
50#ifndef LIBSTDCXX_STATIC
51#define LIBSTDCXX_STATIC NULL
52#endif
53
54#ifndef LIBCXX
55#define LIBCXX "c++"
56#endif
57#ifndef LIBCXX_PROFILE
58#define LIBCXX_PROFILE LIBCXX
59#endif
60#ifndef LIBCXX_STATIC
61#define LIBCXX_STATIC NULL
62#endif
63
64#ifndef LIBCXXABI
65#define LIBCXXABI "c++abi"
66#endif
67#ifndef LIBCXXABI_PROFILE
68#define LIBCXXABI_PROFILE LIBCXXABI
69#endif
70#ifndef LIBCXXABI_STATIC
71#define LIBCXXABI_STATIC NULL
72#endif
73
74/* The values used here must match those of the stdlib_kind enumeration
75 in c.opt. */
76enum stdcxxlib_kind
77{
78 USE_LIBSTDCXX = 1,
79 USE_LIBCXX = 2
80};
81
82void
83lang_specific_driver (struct cl_decoded_option **in_decoded_options,
84 unsigned int *in_decoded_options_count,
85 int *in_added_libraries)
86{
87 unsigned int i, j;
88
89 /* If nonzero, the user gave us the `-p' or `-pg' flag. */
90 int saw_profile_flag = 0;
91
92 /* What action to take for the c++ runtime library:
93 -1 means we should not link it in.
94 0 means we should link it if it is needed.
95 1 means it is needed and should be linked in.
96 2 means it is needed but should be linked statically. */
97 int library = 0;
98
99 /* Which c++ runtime library to link. */
100 stdcxxlib_kind which_library = USE_LIBSTDCXX;
101
102 /* The number of arguments being added to what's in argv, other than
103 libraries. We use this to track the number of times we've inserted
104 -xc++/-xnone. */
105 int added = 0;
106
107 /* The new argument list will be contained in this. */
108 struct cl_decoded_option *new_decoded_options;
109
110 /* Nonzero if we saw a `-xfoo' language specification on the
111 command line. Used to avoid adding our own -xc++ if the user
112 already gave a language for the file. */
113 int saw_speclang = 0;
114
115 /* "-lm" or "-lmath" if it appears on the command line. */
116 const struct cl_decoded_option *saw_math = NULL;
117
118 /* "-lrt" or eqivalent if it appears on the command line. */
119 const struct cl_decoded_option *saw_time = NULL;
120
121 /* "-lc" if it appears on the command line. */
122 const struct cl_decoded_option *saw_libc = NULL;
123
124 /* An array used to flag each argument that needs a bit set for
125 LANGSPEC, MATHLIB, or WITHLIBC. */
126 int *args;
127
128 /* By default, we throw on the math library if we have one. */
129 int need_math = (MATH_LIBRARY[0] != '\0');
130
131 /* By default, we don't add -lstdc++exp. */
132 bool need_experimental = false;
133
134 /* True if we saw -static. */
135 int static_link = 0;
136
137 /* True if we should add -shared-libgcc to the command-line. */
138 int shared_libgcc = 1;
139
140 /* The total number of arguments with the new stuff. */
141 unsigned int argc;
142
143 /* The argument list. */
144 struct cl_decoded_option *decoded_options;
145
146 /* The number of libraries added in. */
147 int added_libraries;
148
149 /* The total number of arguments with the new stuff. */
150 unsigned int num_args = 1;
151
152 argc = *in_decoded_options_count;
153 decoded_options = *in_decoded_options;
154 added_libraries = *in_added_libraries;
155
156 args = XCNEWVEC (int, argc);
157
158 for (i = 1; i < argc; i++)
159 {
160 const char *arg = decoded_options[i].arg;
161 if (decoded_options[i].errors & CL_ERR_MISSING_ARG)
162 continue; /* Avoid examining arguments of options missing them. */
163
164 switch (decoded_options[i].opt_index)
165 {
166 case OPT_fcontracts:
167 need_experimental = true;
168 break;
169
170 case OPT_nostdlib__:
171 args[i] |= SKIPOPT;
172 /* FALLTHRU */
173 case OPT_nostdlib:
174 case OPT_nodefaultlibs:
175 library = -1;
176 break;
177
178 case OPT_l:
179 if (strcmp (s1: arg, MATH_LIBRARY) == 0)
180 {
181 args[i] |= MATHLIB;
182 need_math = 0;
183 }
184 else if (strcmp (s1: arg, s2: "c") == 0)
185 args[i] |= WITHLIBC;
186 else
187 /* Unrecognized libraries (e.g. -lfoo) may require libstdc++. */
188 library = (library == 0) ? 1 : library;
189 break;
190
191 case OPT_pg:
192 case OPT_p:
193 saw_profile_flag++;
194 break;
195
196 case OPT_x:
197 if (library == 0
198 && (strcmp (s1: arg, s2: "c++") == 0
199 || strcmp (s1: arg, s2: "c++-cpp-output") == 0
200 || strcmp (s1: arg, s2: "objective-c++") == 0
201 || strcmp (s1: arg, s2: "objective-c++-cpp-output") == 0))
202 library = 1;
203
204 saw_speclang = 1;
205 break;
206
207 case OPT_Xlinker:
208 case OPT_Wl_:
209 /* Arguments that go directly to the linker might be .o files,
210 or something, and so might cause libstdc++ to be needed. */
211 if (library == 0)
212 library = 1;
213 break;
214
215 case OPT_c:
216 case OPT_r:
217 case OPT_S:
218 case OPT_E:
219 case OPT_M:
220 case OPT_MM:
221 case OPT_fsyntax_only:
222 /* Don't specify libraries if we won't link, since that would
223 cause a warning. */
224 library = -1;
225 break;
226
227 case OPT_static:
228 static_link = 1;
229 break;
230
231 case OPT_static_libgcc:
232 shared_libgcc = 0;
233 break;
234
235 case OPT_static_libstdc__:
236 library = library >= 0 ? 2 : library;
237#ifdef HAVE_LD_STATIC_DYNAMIC
238 /* Remove -static-libstdc++ from the command only if target supports
239 LD_STATIC_DYNAMIC. When not supported, it is left in so that a
240 back-end target can use outfile substitution. */
241 args[i] |= SKIPOPT;
242#endif
243 break;
244
245 case OPT_stdlib_:
246 which_library = (stdcxxlib_kind) decoded_options[i].value;
247 break;
248
249 case OPT_SPECIAL_input_file:
250 {
251 int len;
252
253 /* We don't do this anymore, since we don't get them with minus
254 signs on them. */
255 if (arg[0] == '\0' || arg[1] == '\0')
256 continue;
257
258 if (saw_speclang)
259 {
260 saw_speclang = 0;
261 continue;
262 }
263
264 /* If the filename ends in .[chi], put options around it.
265 But not if a specified -x option is currently active. */
266 len = strlen (s: arg);
267 if (len > 2
268 && (arg[len - 1] == 'c'
269 || arg[len - 1] == 'i'
270 || arg[len - 1] == 'h')
271 && arg[len - 2] == '.')
272 {
273 args[i] |= LANGSPEC;
274 added += 2;
275 }
276
277 /* If we don't know that this is a header file, we might
278 need to be linking in the libraries. */
279 if (library == 0)
280 {
281 if ((len <= 2 || strcmp (s1: arg + (len - 2), s2: ".H") != 0)
282 && (len <= 2 || strcmp (s1: arg + (len - 2), s2: ".h") != 0)
283 && (len <= 4 || strcmp (s1: arg + (len - 4), s2: ".hpp") != 0)
284 && (len <= 3 || strcmp (s1: arg + (len - 3), s2: ".hp") != 0)
285 && (len <= 4 || strcmp (s1: arg + (len - 4), s2: ".hxx") != 0)
286 && (len <= 4 || strcmp (s1: arg + (len - 4), s2: ".h++") != 0)
287 && (len <= 4 || strcmp (s1: arg + (len - 4), s2: ".HPP") != 0)
288 && (len <= 4 || strcmp (s1: arg + (len - 4), s2: ".tcc") != 0)
289 && (len <= 3 || strcmp (s1: arg + (len - 3), s2: ".hh") != 0))
290 library = 1;
291 }
292 }
293 break;
294 }
295 }
296
297 /* There's no point adding -shared-libgcc if we don't have a shared
298 libgcc. */
299#ifndef ENABLE_SHARED_LIBGCC
300 shared_libgcc = 0;
301#endif
302
303 /* Add one for shared_libgcc or extra static library. */
304 num_args = (argc + added + need_math + need_experimental
305 + (library > 0) * 4 + 1);
306 /* For libc++, on most platforms, the ABI library (usually called libc++abi)
307 is provided as a separate DSO, which we must also append.
308 However, a platform might have the ability to forward the ABI library
309 from libc++, or combine it in some other way; in that case, LIBCXXABI
310 should be set to NULL to signal that it need not be appended. */
311 if (which_library == USE_LIBCXX && LIBCXXABI != NULL)
312 num_args += 4;
313 new_decoded_options = XNEWVEC (struct cl_decoded_option, num_args);
314
315 i = 0;
316 j = 0;
317
318 /* Copy the 0th argument, i.e., the name of the program itself. */
319 new_decoded_options[j++] = decoded_options[i++];
320
321 /* NOTE: We start at 1 now, not 0. */
322 while (i < argc)
323 {
324 new_decoded_options[j] = decoded_options[i];
325
326 /* Make sure -lstdc++ is before the math library, since libstdc++
327 itself uses those math routines. */
328 if (!saw_math && (args[i] & MATHLIB) && library > 0)
329 {
330 --j;
331 saw_math = &decoded_options[i];
332 }
333
334 if (!saw_libc && (args[i] & WITHLIBC) && library > 0)
335 {
336 --j;
337 saw_libc = &decoded_options[i];
338 }
339
340 /* Wrap foo.[chi] files in a language specification to
341 force the gcc compiler driver to run cc1plus on them. */
342 if (args[i] & LANGSPEC)
343 {
344 const char *arg = decoded_options[i].arg;
345 int len = strlen (s: arg);
346 switch (arg[len - 1])
347 {
348 case 'c':
349 generate_option (opt_index: OPT_x, arg: "c++", value: 1, CL_DRIVER,
350 decoded: &new_decoded_options[j++]);
351 break;
352 case 'i':
353 generate_option (opt_index: OPT_x, arg: "c++-cpp-output", value: 1, CL_DRIVER,
354 decoded: &new_decoded_options[j++]);
355 break;
356 case 'h':
357 generate_option (opt_index: OPT_x, arg: "c++-header", value: 1, CL_DRIVER,
358 decoded: &new_decoded_options[j++]);
359 break;
360 default:
361 gcc_unreachable ();
362 }
363 new_decoded_options[j++] = decoded_options[i];
364 generate_option (opt_index: OPT_x, arg: "none", value: 1, CL_DRIVER,
365 decoded: &new_decoded_options[j]);
366 }
367
368 if ((args[i] & SKIPOPT) != 0)
369 --j;
370
371 i++;
372 j++;
373 }
374
375 /* Add `-lstdc++' if we haven't already done so. */
376 if (library > 0)
377 {
378 if (need_experimental && which_library == USE_LIBSTDCXX)
379 {
380 generate_option (opt_index: OPT_l, arg: "stdc++exp", value: 1, CL_DRIVER,
381 decoded: &new_decoded_options[j++]);
382 ++added_libraries;
383 }
384#ifdef HAVE_LD_STATIC_DYNAMIC
385 if (library > 1 && !static_link)
386 {
387 generate_option (opt_index: OPT_Wl_, LD_STATIC_OPTION, value: 1, CL_DRIVER,
388 decoded: &new_decoded_options[j]);
389 j++;
390 }
391#endif
392 if (which_library == USE_LIBCXX)
393 {
394 generate_option (opt_index: OPT_l,
395 arg: saw_profile_flag ? LIBCXX_PROFILE : LIBCXX, value: 1,
396 CL_DRIVER, decoded: &new_decoded_options[j]);
397 if (LIBCXXABI != NULL)
398 {
399 j++;
400 added_libraries++;
401 generate_option (opt_index: OPT_l,
402 arg: saw_profile_flag ? LIBCXXABI_PROFILE
403 : LIBCXXABI, value: 1,
404 CL_DRIVER, decoded: &new_decoded_options[j]);
405 }
406 }
407 else
408 generate_option (opt_index: OPT_l,
409 arg: saw_profile_flag ? LIBSTDCXX_PROFILE : LIBSTDCXX, value: 1,
410 CL_DRIVER, decoded: &new_decoded_options[j]);
411 added_libraries++;
412 j++;
413 /* Add target-dependent static library, if necessary. */
414 if ((static_link || library > 1) && LIBSTDCXX_STATIC != NULL)
415 {
416 generate_option (opt_index: OPT_l, LIBSTDCXX_STATIC, value: 1,
417 CL_DRIVER, decoded: &new_decoded_options[j]);
418 added_libraries++;
419 j++;
420 }
421#ifdef HAVE_LD_STATIC_DYNAMIC
422 if (library > 1 && !static_link)
423 {
424 generate_option (opt_index: OPT_Wl_, LD_DYNAMIC_OPTION, value: 1, CL_DRIVER,
425 decoded: &new_decoded_options[j]);
426 j++;
427 }
428#endif
429 }
430 if (saw_math)
431 new_decoded_options[j++] = *saw_math;
432 else if (library > 0 && need_math)
433 {
434 generate_option (opt_index: OPT_l,
435 arg: saw_profile_flag ? MATH_LIBRARY_PROFILE : MATH_LIBRARY,
436 value: 1, CL_DRIVER, decoded: &new_decoded_options[j]);
437 added_libraries++;
438 j++;
439 }
440 if (saw_time)
441 new_decoded_options[j++] = *saw_time;
442 if (saw_libc)
443 new_decoded_options[j++] = *saw_libc;
444 if (shared_libgcc && !static_link)
445 generate_option (opt_index: OPT_shared_libgcc, NULL, value: 1, CL_DRIVER,
446 decoded: &new_decoded_options[j++]);
447
448 *in_decoded_options_count = j;
449 *in_decoded_options = new_decoded_options;
450 *in_added_libraries = added_libraries;
451}
452
453/* Called before linking. Returns 0 on success and -1 on failure. */
454int lang_specific_pre_link (void) /* Not used for C++. */
455{
456 return 0;
457}
458
459/* Number of extra output files that lang_specific_pre_link may generate. */
460int lang_specific_extra_outfiles = 0; /* Not used for C++. */
461

source code of gcc/cp/g++spec.cc