1 /* LTO IL options.
2
3 Copyright (C) 2009-2014 Free Software Foundation, Inc.
4 Contributed by Simon Baldwin <simonb@google.com>
5
6 This file is part of GCC.
7
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
21
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "tree.h"
26 #include "basic-block.h"
27 #include "tree-ssa-alias.h"
28 #include "internal-fn.h"
29 #include "gimple-expr.h"
30 #include "is-a.h"
31 #include "gimple.h"
32 #include "hashtab.h"
33 #include "bitmap.h"
34 #include "flags.h"
35 #include "opts.h"
36 #include "options.h"
37 #include "common/common-target.h"
38 #include "diagnostic.h"
39 #include "lto-streamer.h"
40 #include "toplev.h"
41
42 /* Append the option piece OPT to the COLLECT_GCC_OPTIONS string
43 set up by OB, appropriately quoted and separated by spaces
44 (if !*FIRST_P). */
45
46 static void
append_to_collect_gcc_options(struct obstack * ob,bool * first_p,const char * opt)47 append_to_collect_gcc_options (struct obstack *ob,
48 bool *first_p, const char *opt)
49 {
50 const char *p, *q = opt;
51 if (!*first_p)
52 obstack_grow (ob, " ", 1);
53 obstack_grow (ob, "'", 1);
54 while ((p = strchr (q, '\'')))
55 {
56 obstack_grow (ob, q, p - q);
57 obstack_grow (ob, "'\\''", 4);
58 q = ++p;
59 }
60 obstack_grow (ob, q, strlen (q));
61 obstack_grow (ob, "'", 1);
62 *first_p = false;
63 }
64
65 /* Write currently held options to an LTO IL section. */
66
67 void
lto_write_options(void)68 lto_write_options (void)
69 {
70 struct lto_output_stream stream;
71 char *section_name;
72 struct obstack temporary_obstack;
73 unsigned int i, j;
74 char *args;
75 bool first_p = true;
76
77 section_name = lto_get_section_name (LTO_section_opts, NULL, NULL);
78 lto_begin_section (section_name, false);
79 memset (&stream, 0, sizeof (stream));
80
81 obstack_init (&temporary_obstack);
82
83 /* Output options that affect GIMPLE IL semantics and are implicitly
84 enabled by the frontend.
85 This for now includes an explicit set of options that we also handle
86 explicitly in lto-wrapper.c. In the end the effects on GIMPLE IL
87 semantics should be explicitely encoded in the IL or saved per
88 function rather than per compilation unit. */
89 /* -fexceptions causes the EH machinery to be initialized, enabling
90 generation of unwind data so that explicit throw() calls work. */
91 if (!global_options_set.x_flag_exceptions
92 && global_options.x_flag_exceptions)
93 append_to_collect_gcc_options (&temporary_obstack, &first_p,
94 "-fexceptions");
95 /* -fnon-call-exceptions changes the generation of exception
96 regions. It is enabled implicitly by the Go frontend. */
97 if (!global_options_set.x_flag_non_call_exceptions
98 && global_options.x_flag_non_call_exceptions)
99 append_to_collect_gcc_options (&temporary_obstack, &first_p,
100 "-fnon-call-exceptions");
101 /* The default -ffp-contract changes depending on the language
102 standard. Pass thru conservative standard settings. */
103 if (!global_options_set.x_flag_fp_contract_mode)
104 switch (global_options.x_flag_fp_contract_mode)
105 {
106 case FP_CONTRACT_OFF:
107 append_to_collect_gcc_options (&temporary_obstack, &first_p,
108 "-ffp-contract=off");
109 break;
110 case FP_CONTRACT_ON:
111 append_to_collect_gcc_options (&temporary_obstack, &first_p,
112 "-ffp-contract=on");
113 break;
114 case FP_CONTRACT_FAST:
115 /* Nothing. That merges conservatively and is the default for LTO. */
116 break;
117 default:
118 gcc_unreachable ();
119 }
120 /* We need to merge -f[no-]strict-overflow, -f[no-]wrapv and -f[no-]trapv
121 conservatively, so stream out their defaults. */
122 if (!global_options_set.x_flag_wrapv
123 && global_options.x_flag_wrapv)
124 append_to_collect_gcc_options (&temporary_obstack, &first_p, "-fwrapv");
125 if (!global_options_set.x_flag_trapv
126 && !global_options.x_flag_trapv)
127 append_to_collect_gcc_options (&temporary_obstack, &first_p, "-fno-trapv");
128 if (!global_options_set.x_flag_strict_overflow
129 && !global_options.x_flag_strict_overflow)
130 append_to_collect_gcc_options (&temporary_obstack, &first_p,
131 "-fno-strict-overflow");
132
133 /* Output explicitly passed options. */
134 for (i = 1; i < save_decoded_options_count; ++i)
135 {
136 struct cl_decoded_option *option = &save_decoded_options[i];
137
138 /* Skip explicitly some common options that we do not need. */
139 switch (option->opt_index)
140 {
141 case OPT_dumpbase:
142 case OPT_SPECIAL_unknown:
143 case OPT_SPECIAL_ignore:
144 case OPT_SPECIAL_program_name:
145 case OPT_SPECIAL_input_file:
146 continue;
147
148 default:
149 break;
150 }
151
152 /* Skip frontend and driver specific options here. */
153 if (!(cl_options[option->opt_index].flags & (CL_COMMON|CL_TARGET|CL_LTO)))
154 continue;
155
156 /* Drop options created from the gcc driver that will be rejected
157 when passed on to the driver again. */
158 if (cl_options[option->opt_index].cl_reject_driver)
159 continue;
160
161 /* Also drop all options that are handled by the driver as well,
162 which includes things like -o and -v or -fhelp for example.
163 We do not need those. Also drop all diagnostic options. */
164 if (cl_options[option->opt_index].flags & (CL_DRIVER|CL_WARNING))
165 continue;
166
167 for (j = 0; j < option->canonical_option_num_elements; ++j)
168 append_to_collect_gcc_options (&temporary_obstack, &first_p,
169 option->canonical_option[j]);
170 }
171 obstack_grow (&temporary_obstack, "\0", 1);
172 args = XOBFINISH (&temporary_obstack, char *);
173 lto_output_data_stream (&stream, args, strlen (args) + 1);
174
175 lto_write_stream (&stream);
176 lto_end_section ();
177
178 obstack_free (&temporary_obstack, NULL);
179 free (section_name);
180 }
181