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1 | /* subsegs.c - subsegments - |
2 | Copyright (C) 1987 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of GAS, the GNU Assembler. | |
5 | ||
6 | GAS is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 1, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GAS is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with GAS; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | /* | |
21 | * Segments & sub-segments. | |
22 | */ | |
23 | ||
24 | #include "as.h" | |
25 | #include "subsegs.h" | |
26 | #include "obstack.h" | |
27 | #include "frags.h" | |
28 | #include "struc-symbol.h" | |
29 | #include "write.h" | |
30 | ||
31 | frchainS* frchain_root, | |
32 | * frchain_now, /* Commented in "subsegs.h". */ | |
33 | * data0_frchainP; | |
34 | ||
35 | ||
36 | const int /* in: segT out: N_TYPE bits */ | |
37 | seg_N_TYPE[] = { | |
38 | N_ABS, | |
39 | N_TEXT, | |
40 | N_DATA, | |
41 | N_BSS, | |
42 | N_UNDF, | |
43 | N_UNDF, | |
44 | N_UNDF, | |
45 | N_UNDF, | |
46 | N_UNDF, | |
47 | N_UNDF | |
48 | }; | |
49 | ||
50 | ||
51 | char * const /* in: segT out: char* */ | |
52 | seg_name[] = { | |
53 | "absolute", | |
54 | "text", | |
55 | "data", | |
56 | "bss", | |
57 | "unknown", | |
58 | "absent", | |
59 | "pass1", | |
60 | "ASSEMBLER-INTERNAL-LOGIC-ERROR!", | |
61 | "bignum/flonum", | |
62 | "difference", | |
63 | "" | |
64 | }; /* Used by error reporters, dumpers etc. */ | |
65 | ||
66 | const segT N_TYPE_seg [N_TYPE+2] = /* N_TYPE == 0x1E = 32-2 */ | |
67 | { | |
68 | SEG_UNKNOWN, /* N_UNDF == 0 */ | |
69 | SEG_GOOF, | |
70 | SEG_ABSOLUTE, /* N_ABS == 2 */ | |
71 | SEG_GOOF, | |
72 | SEG_TEXT, /* N_TEXT == 4 */ | |
73 | SEG_GOOF, | |
74 | SEG_DATA, /* N_DATA == 6 */ | |
75 | SEG_GOOF, | |
76 | SEG_BSS, /* N_BSS == 8 */ | |
77 | SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, | |
78 | SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, | |
79 | SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF | |
80 | }; | |
81 | \f | |
82 | void | |
83 | subsegs_begin() | |
84 | { | |
85 | /* Check table(s) seg_name[], seg_N_TYPE[] is in correct order */ | |
86 | know( SEG_ABSOLUTE ==0 ); | |
87 | know( SEG_TEXT ==1 ); | |
88 | know( SEG_DATA ==2 ); | |
89 | know( SEG_BSS ==3 ); | |
90 | know( SEG_UNKNOWN ==4 ); | |
91 | know( SEG_NONE ==5 ); | |
92 | know( SEG_PASS1 ==6 ); | |
93 | know( SEG_GOOF ==7 ); | |
94 | know( SEG_BIG ==8 ); | |
95 | know( SEG_DIFFERENCE ==9 ); | |
96 | know( SEG_MAXIMUM_ORDINAL == SEG_DIFFERENCE ); | |
97 | know( seg_name [(int) SEG_MAXIMUM_ORDINAL + 1] [0] == 0 ); | |
98 | ||
99 | obstack_begin( &frags, 5000); | |
100 | frchain_root = NULL; | |
101 | frchain_now = NULL; /* Warn new_subseg() that we are booting. */ | |
102 | /* Fake up 1st frag. */ | |
103 | /* It won't be used=> is ok if obstack... */ | |
104 | /* pads the end of it for alignment. */ | |
105 | frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); | |
106 | /* obstack_1blank( &frags, SIZEOF_STRUCT_FRAG, & frag_now ); */ | |
107 | /* This 1st frag will not be in any frchain. */ | |
108 | /* We simply give subseg_new somewhere to scribble. */ | |
109 | now_subseg = 42; /* Lie for 1st call to subseg_new. */ | |
110 | subseg_new (SEG_DATA, 0); /* .data 0 */ | |
111 | data0_frchainP = frchain_now; | |
112 | } | |
113 | \f | |
114 | /* | |
115 | * subseg_change() | |
116 | * | |
117 | * Change the subsegment we are in, BUT DO NOT MAKE A NEW FRAG for the | |
118 | * subsegment. If we are already in the correct subsegment, change nothing. | |
119 | * This is used eg as a worker for subseg_new [which does make a new frag_now] | |
120 | * and for changing segments after we have read the source. We construct eg | |
121 | * fixSs even after the source file is read, so we do have to keep the | |
122 | * segment context correct. | |
123 | */ | |
124 | void | |
125 | subseg_change (seg, subseg) | |
126 | register segT seg; | |
127 | register int subseg; | |
128 | { | |
129 | now_seg = seg; | |
130 | now_subseg = subseg; | |
131 | if (seg == SEG_DATA) | |
132 | { | |
133 | seg_fix_rootP = & data_fix_root; | |
134 | } | |
135 | else | |
136 | { | |
137 | know (seg == SEG_TEXT); | |
138 | seg_fix_rootP = & text_fix_root; | |
139 | } | |
140 | } | |
141 | \f | |
142 | /* | |
143 | * subseg_new() | |
144 | * | |
145 | * If you attempt to change to the current subsegment, nothing happens. | |
146 | * | |
147 | * In: segT, subsegT code for new subsegment. | |
148 | * frag_now -> incomplete frag for current subsegment. | |
149 | * If frag_now==NULL, then there is no old, incomplete frag, so | |
150 | * the old frag is not closed off. | |
151 | * | |
152 | * Out: now_subseg, now_seg updated. | |
153 | * Frchain_now points to the (possibly new) struct frchain for this | |
154 | * sub-segment. | |
155 | * Frchain_root updated if needed. | |
156 | */ | |
157 | ||
158 | void | |
159 | subseg_new (seg, subseg) /* begin assembly for a new sub-segment */ | |
160 | register segT seg; /* SEG_DATA or SEG_TEXT */ | |
161 | register subsegT subseg; | |
162 | { | |
163 | long tmp; /* JF for obstack alignment hacking */ | |
164 | ||
165 | know( seg == SEG_DATA || seg == SEG_TEXT ); | |
166 | ||
167 | if (seg != now_seg || subseg != now_subseg) | |
168 | { /* we just changed sub-segments */ | |
169 | register frchainS * frcP; /* crawl frchain chain */ | |
170 | register frchainS** lastPP; /* address of last pointer */ | |
171 | frchainS * newP; /* address of new frchain */ | |
172 | register fragS * former_last_fragP; | |
173 | register fragS * new_fragP; | |
174 | ||
175 | if (frag_now) /* If not bootstrapping. */ | |
176 | { | |
177 | frag_now -> fr_fix = obstack_next_free(& frags) - frag_now -> fr_literal; | |
178 | frag_wane(frag_now); /* Close off any frag in old subseg. */ | |
179 | } | |
180 | /* | |
181 | * It would be nice to keep an obstack for each subsegment, if we swap | |
182 | * subsegments a lot. Hence we would have much fewer frag_wanes(). | |
183 | */ | |
184 | { | |
185 | ||
186 | obstack_finish( &frags); | |
187 | /* | |
188 | * If we don't do the above, the next object we put on obstack frags | |
189 | * will appear to start at the fr_literal of the current frag. | |
190 | * Also, above ensures that the next object will begin on a | |
191 | * address that is aligned correctly for the engine that runs | |
192 | * this program. | |
193 | */ | |
194 | } | |
195 | subseg_change (seg, (int)subseg); | |
196 | /* | |
197 | * Attempt to find or make a frchain for that sub seg. | |
198 | * Crawl along chain of frchainSs, begins @ frchain_root. | |
199 | * If we need to make a frchainS, link it into correct | |
200 | * position of chain rooted in frchain_root. | |
201 | */ | |
202 | for (frcP = * (lastPP = & frchain_root); | |
203 | frcP | |
204 | && (int)(frcP -> frch_seg) <= (int)seg; | |
205 | frcP = * ( lastPP = & frcP -> frch_next) | |
206 | ) | |
207 | { | |
208 | if ( (int)(frcP -> frch_seg) == (int)seg | |
209 | && frcP -> frch_subseg >= subseg) | |
210 | { | |
211 | break; | |
212 | } | |
213 | } | |
214 | /* | |
215 | * frcP: Address of the 1st frchainS in correct segment with | |
216 | * frch_subseg >= subseg. | |
217 | * We want to either use this frchainS, or we want | |
218 | * to insert a new frchainS just before it. | |
219 | * | |
220 | * If frcP==NULL, then we are at the end of the chain | |
221 | * of frchainS-s. A NULL frcP means we fell off the end | |
222 | * of the chain looking for a | |
223 | * frch_subseg >= subseg, so we | |
224 | * must make a new frchainS. | |
225 | * | |
226 | * If we ever maintain a pointer to | |
227 | * the last frchainS in the chain, we change that pointer | |
228 | * ONLY when frcP==NULL. | |
229 | * | |
230 | * lastPP: Address of the pointer with value frcP; | |
231 | * Never NULL. | |
232 | * May point to frchain_root. | |
233 | * | |
234 | */ | |
235 | if ( ! frcP | |
236 | || ( (int)(frcP -> frch_seg) > (int)seg | |
237 | || frcP->frch_subseg > subseg)) /* Kinky logic only works with 2 segments. */ | |
238 | { | |
239 | /* | |
240 | * This should be the only code that creates a frchainS. | |
241 | */ | |
242 | newP=(frchainS *)obstack_alloc(&frags,sizeof(frchainS)); | |
243 | /* obstack_1blank( &frags, sizeof(frchainS), &newP); */ | |
244 | /* This begines on a good boundary */ | |
245 | /* because a obstack_done() preceeded it. */ | |
246 | /* It implies an obstack_done(), so we */ | |
247 | /* expect the next object allocated to */ | |
248 | /* begin on a correct boundary. */ | |
249 | *lastPP = newP; | |
250 | newP -> frch_next = frcP; /* perhaps NULL */ | |
251 | (frcP = newP) -> frch_subseg = subseg; | |
252 | newP -> frch_seg = seg; | |
253 | newP -> frch_last = NULL; | |
254 | } | |
255 | /* | |
256 | * Here with frcP ->ing to the frchainS for subseg. | |
257 | */ | |
258 | frchain_now = frcP; | |
259 | /* | |
260 | * Make a fresh frag for the subsegment. | |
261 | */ | |
262 | /* We expect this to happen on a correct */ | |
263 | /* boundary since it was proceeded by a */ | |
264 | /* obstack_done(). */ | |
265 | tmp=obstack_alignment_mask(&frags); /* JF disable alignment */ | |
266 | obstack_alignment_mask(&frags)=0; | |
267 | frag_now=(fragS *)obstack_alloc(&frags,SIZEOF_STRUCT_FRAG); | |
268 | obstack_alignment_mask(&frags)=tmp; | |
269 | /* know( frags . obstack_c_next_free == frag_now -> fr_literal ); */ | |
270 | /* But we want any more chars to come */ | |
271 | /* immediately after the structure we just made. */ | |
272 | new_fragP = frag_now; | |
273 | new_fragP -> fr_next = NULL; | |
274 | /* | |
275 | * Append new frag to current frchain. | |
276 | */ | |
277 | former_last_fragP = frcP -> frch_last; | |
278 | if (former_last_fragP) | |
279 | { | |
280 | know( former_last_fragP -> fr_next == NULL ); | |
281 | know( frchain_now -> frch_root ); | |
282 | former_last_fragP -> fr_next = new_fragP; | |
283 | } | |
284 | else | |
285 | { | |
286 | frcP -> frch_root = new_fragP; | |
287 | } | |
288 | frcP -> frch_last = new_fragP; | |
289 | } /* if (changing subsegments) */ | |
290 | } /* subseg_new() */ | |
291 | ||
292 | /* end: subsegs.c */ |