1 /*
2 ** DynASM PPC/PPC64 encoding engine.
3 ** Copyright (C) 2005-2016 Mike Pall. All rights reserved.
4 ** Released under the MIT license. See dynasm.lua for full copyright notice.
5 */
6
7 #include <stddef.h>
8 #include <stdarg.h>
9 #include <string.h>
10 #include <stdlib.h>
11
12 #define DASM_ARCH "ppc"
13
14 #ifndef DASM_EXTERN
15 #define DASM_EXTERN(a,b,c,d) 0
16 #endif
17
18 /* Action definitions. */
19 enum {
20 DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT,
21 /* The following actions need a buffer position. */
22 DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG,
23 /* The following actions also have an argument. */
24 DASM_REL_PC, DASM_LABEL_PC, DASM_IMM, DASM_IMMSH,
25 DASM__MAX
26 };
27
28 /* Maximum number of section buffer positions for a single dasm_put() call. */
29 #define DASM_MAXSECPOS 25
30
31 /* DynASM encoder status codes. Action list offset or number are or'ed in. */
32 #define DASM_S_OK 0x00000000
33 #define DASM_S_NOMEM 0x01000000
34 #define DASM_S_PHASE 0x02000000
35 #define DASM_S_MATCH_SEC 0x03000000
36 #define DASM_S_RANGE_I 0x11000000
37 #define DASM_S_RANGE_SEC 0x12000000
38 #define DASM_S_RANGE_LG 0x13000000
39 #define DASM_S_RANGE_PC 0x14000000
40 #define DASM_S_RANGE_REL 0x15000000
41 #define DASM_S_UNDEF_LG 0x21000000
42 #define DASM_S_UNDEF_PC 0x22000000
43
44 /* Macros to convert positions (8 bit section + 24 bit index). */
45 #define DASM_POS2IDX(pos) ((pos)&0x00ffffff)
46 #define DASM_POS2BIAS(pos) ((pos)&0xff000000)
47 #define DASM_SEC2POS(sec) ((sec)<<24)
48 #define DASM_POS2SEC(pos) ((pos)>>24)
49 #define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos))
50
51 /* Action list type. */
52 typedef const unsigned int *dasm_ActList;
53
54 /* Per-section structure. */
55 typedef struct dasm_Section {
56 int *rbuf; /* Biased buffer pointer (negative section bias). */
57 int *buf; /* True buffer pointer. */
58 size_t bsize; /* Buffer size in bytes. */
59 int pos; /* Biased buffer position. */
60 int epos; /* End of biased buffer position - max single put. */
61 int ofs; /* Byte offset into section. */
62 } dasm_Section;
63
64 /* Core structure holding the DynASM encoding state. */
65 struct dasm_State {
66 size_t psize; /* Allocated size of this structure. */
67 dasm_ActList actionlist; /* Current actionlist pointer. */
68 int *lglabels; /* Local/global chain/pos ptrs. */
69 size_t lgsize;
70 int *pclabels; /* PC label chains/pos ptrs. */
71 size_t pcsize;
72 void **globals; /* Array of globals (bias -10). */
73 dasm_Section *section; /* Pointer to active section. */
74 size_t codesize; /* Total size of all code sections. */
75 int maxsection; /* 0 <= sectionidx < maxsection. */
76 int status; /* Status code. */
77 dasm_Section sections[1]; /* All sections. Alloc-extended. */
78 };
79
80 /* The size of the core structure depends on the max. number of sections. */
81 #define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section))
82
83
84 /* Initialize DynASM state. */
dasm_init(Dst_DECL,int maxsection)85 void dasm_init(Dst_DECL, int maxsection)
86 {
87 dasm_State *D;
88 size_t psz = 0;
89 int i;
90 Dst_REF = NULL;
91 DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection));
92 D = Dst_REF;
93 D->psize = psz;
94 D->lglabels = NULL;
95 D->lgsize = 0;
96 D->pclabels = NULL;
97 D->pcsize = 0;
98 D->globals = NULL;
99 D->maxsection = maxsection;
100 for (i = 0; i < maxsection; i++) {
101 D->sections[i].buf = NULL; /* Need this for pass3. */
102 D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i);
103 D->sections[i].bsize = 0;
104 D->sections[i].epos = 0; /* Wrong, but is recalculated after resize. */
105 }
106 }
107
108 /* Free DynASM state. */
dasm_free(Dst_DECL)109 void dasm_free(Dst_DECL)
110 {
111 dasm_State *D = Dst_REF;
112 int i;
113 for (i = 0; i < D->maxsection; i++)
114 if (D->sections[i].buf)
115 DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize);
116 if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize);
117 if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize);
118 DASM_M_FREE(Dst, D, D->psize);
119 }
120
121 /* Setup global label array. Must be called before dasm_setup(). */
dasm_setupglobal(Dst_DECL,void ** gl,unsigned int maxgl)122 void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl)
123 {
124 dasm_State *D = Dst_REF;
125 D->globals = gl - 10; /* Negative bias to compensate for locals. */
126 DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int));
127 }
128
129 /* Grow PC label array. Can be called after dasm_setup(), too. */
dasm_growpc(Dst_DECL,unsigned int maxpc)130 void dasm_growpc(Dst_DECL, unsigned int maxpc)
131 {
132 dasm_State *D = Dst_REF;
133 size_t osz = D->pcsize;
134 DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int));
135 memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz);
136 }
137
138 /* Setup encoder. */
dasm_setup(Dst_DECL,const void * actionlist)139 void dasm_setup(Dst_DECL, const void *actionlist)
140 {
141 dasm_State *D = Dst_REF;
142 int i;
143 D->actionlist = (dasm_ActList)actionlist;
144 D->status = DASM_S_OK;
145 D->section = &D->sections[0];
146 memset((void *)D->lglabels, 0, D->lgsize);
147 if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize);
148 for (i = 0; i < D->maxsection; i++) {
149 D->sections[i].pos = DASM_SEC2POS(i);
150 D->sections[i].ofs = 0;
151 }
152 }
153
154
155 #ifdef DASM_CHECKS
156 #define CK(x, st) \
157 do { if (!(x)) { \
158 D->status = DASM_S_##st|(p-D->actionlist-1); return; } } while (0)
159 #define CKPL(kind, st) \
160 do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \
161 D->status = DASM_S_RANGE_##st|(p-D->actionlist-1); return; } } while (0)
162 #else
163 #define CK(x, st) ((void)0)
164 #define CKPL(kind, st) ((void)0)
165 #endif
166
167 /* Pass 1: Store actions and args, link branches/labels, estimate offsets. */
dasm_put(Dst_DECL,int start,...)168 void dasm_put(Dst_DECL, int start, ...)
169 {
170 va_list ap;
171 dasm_State *D = Dst_REF;
172 dasm_ActList p = D->actionlist + start;
173 dasm_Section *sec = D->section;
174 int pos = sec->pos, ofs = sec->ofs;
175 int *b;
176
177 if (pos >= sec->epos) {
178 DASM_M_GROW(Dst, int, sec->buf, sec->bsize,
179 sec->bsize + 2*DASM_MAXSECPOS*sizeof(int));
180 sec->rbuf = sec->buf - DASM_POS2BIAS(pos);
181 sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos);
182 }
183
184 b = sec->rbuf;
185 b[pos++] = start;
186
187 va_start(ap, start);
188 while (1) {
189 unsigned int ins = *p++;
190 unsigned int action = (ins >> 16);
191 if (action >= DASM__MAX) {
192 ofs += 4;
193 } else {
194 int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0;
195 switch (action) {
196 case DASM_STOP: goto stop;
197 case DASM_SECTION:
198 n = (ins & 255); CK(n < D->maxsection, RANGE_SEC);
199 D->section = &D->sections[n]; goto stop;
200 case DASM_ESC: p++; ofs += 4; break;
201 case DASM_REL_EXT: break;
202 case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break;
203 case DASM_REL_LG:
204 n = (ins & 2047) - 10; pl = D->lglabels + n;
205 /* Bkwd rel or global. */
206 if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; }
207 pl += 10; n = *pl;
208 if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */
209 goto linkrel;
210 case DASM_REL_PC:
211 pl = D->pclabels + n; CKPL(pc, PC);
212 putrel:
213 n = *pl;
214 if (n < 0) { /* Label exists. Get label pos and store it. */
215 b[pos] = -n;
216 } else {
217 linkrel:
218 b[pos] = n; /* Else link to rel chain, anchored at label. */
219 *pl = pos;
220 }
221 pos++;
222 break;
223 case DASM_LABEL_LG:
224 pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel;
225 case DASM_LABEL_PC:
226 pl = D->pclabels + n; CKPL(pc, PC);
227 putlabel:
228 n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */
229 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos;
230 }
231 *pl = -pos; /* Label exists now. */
232 b[pos++] = ofs; /* Store pass1 offset estimate. */
233 break;
234 case DASM_IMM:
235 #ifdef DASM_CHECKS
236 CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I);
237 #endif
238 n >>= ((ins>>10)&31);
239 #ifdef DASM_CHECKS
240 if (ins & 0x8000)
241 CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I);
242 else
243 CK((n>>((ins>>5)&31)) == 0, RANGE_I);
244 #endif
245 b[pos++] = n;
246 break;
247 case DASM_IMMSH:
248 CK((n >> 6) == 0, RANGE_I);
249 b[pos++] = n;
250 break;
251 }
252 }
253 }
254 stop:
255 va_end(ap);
256 sec->pos = pos;
257 sec->ofs = ofs;
258 }
259 #undef CK
260
261 /* Pass 2: Link sections, shrink aligns, fix label offsets. */
dasm_link(Dst_DECL,size_t * szp)262 int dasm_link(Dst_DECL, size_t *szp)
263 {
264 dasm_State *D = Dst_REF;
265 int secnum;
266 int ofs = 0;
267
268 #ifdef DASM_CHECKS
269 *szp = 0;
270 if (D->status != DASM_S_OK) return D->status;
271 {
272 int pc;
273 for (pc = 0; pc*sizeof(int) < D->pcsize; pc++)
274 if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc;
275 }
276 #endif
277
278 { /* Handle globals not defined in this translation unit. */
279 int idx;
280 for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) {
281 int n = D->lglabels[idx];
282 /* Undefined label: Collapse rel chain and replace with marker (< 0). */
283 while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; }
284 }
285 }
286
287 /* Combine all code sections. No support for data sections (yet). */
288 for (secnum = 0; secnum < D->maxsection; secnum++) {
289 dasm_Section *sec = D->sections + secnum;
290 int *b = sec->rbuf;
291 int pos = DASM_SEC2POS(secnum);
292 int lastpos = sec->pos;
293
294 while (pos != lastpos) {
295 dasm_ActList p = D->actionlist + b[pos++];
296 while (1) {
297 unsigned int ins = *p++;
298 unsigned int action = (ins >> 16);
299 switch (action) {
300 case DASM_STOP: case DASM_SECTION: goto stop;
301 case DASM_ESC: p++; break;
302 case DASM_REL_EXT: break;
303 case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break;
304 case DASM_REL_LG: case DASM_REL_PC: pos++; break;
305 case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break;
306 case DASM_IMM: case DASM_IMMSH: pos++; break;
307 }
308 }
309 stop: (void)0;
310 }
311 ofs += sec->ofs; /* Next section starts right after current section. */
312 }
313
314 D->codesize = ofs; /* Total size of all code sections */
315 *szp = ofs;
316 return DASM_S_OK;
317 }
318
319 #ifdef DASM_CHECKS
320 #define CK(x, st) \
321 do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0)
322 #else
323 #define CK(x, st) ((void)0)
324 #endif
325
326 /* Pass 3: Encode sections. */
dasm_encode(Dst_DECL,void * buffer)327 int dasm_encode(Dst_DECL, void *buffer)
328 {
329 dasm_State *D = Dst_REF;
330 char *base = (char *)buffer;
331 unsigned int *cp = (unsigned int *)buffer;
332 int secnum;
333
334 /* Encode all code sections. No support for data sections (yet). */
335 for (secnum = 0; secnum < D->maxsection; secnum++) {
336 dasm_Section *sec = D->sections + secnum;
337 int *b = sec->buf;
338 int *endb = sec->rbuf + sec->pos;
339
340 while (b != endb) {
341 dasm_ActList p = D->actionlist + *b++;
342 while (1) {
343 unsigned int ins = *p++;
344 unsigned int action = (ins >> 16);
345 int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0;
346 switch (action) {
347 case DASM_STOP: case DASM_SECTION: goto stop;
348 case DASM_ESC: *cp++ = *p++; break;
349 case DASM_REL_EXT:
350 n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins & 2047), 1) - 4;
351 goto patchrel;
352 case DASM_ALIGN:
353 ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0x60000000;
354 break;
355 case DASM_REL_LG:
356 CK(n >= 0, UNDEF_LG);
357 case DASM_REL_PC:
358 CK(n >= 0, UNDEF_PC);
359 n = *DASM_POS2PTR(D, n) - (int)((char *)cp - base);
360 patchrel:
361 CK((n & 3) == 0 &&
362 (((n+4) + ((ins & 2048) ? 0x00008000 : 0x02000000)) >>
363 ((ins & 2048) ? 16 : 26)) == 0, RANGE_REL);
364 cp[-1] |= ((n+4) & ((ins & 2048) ? 0x0000fffc: 0x03fffffc));
365 break;
366 case DASM_LABEL_LG:
367 ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n);
368 break;
369 case DASM_LABEL_PC: break;
370 case DASM_IMM:
371 cp[-1] |= (n & ((1<<((ins>>5)&31))-1)) << (ins&31);
372 break;
373 case DASM_IMMSH:
374 cp[-1] |= (ins & 1) ? ((n&31)<<11)|((n&32)>>4) : ((n&31)<<6)|(n&32);
375 break;
376 default: *cp++ = ins; break;
377 }
378 }
379 stop: (void)0;
380 }
381 }
382
383 if (base + D->codesize != (char *)cp) /* Check for phase errors. */
384 return DASM_S_PHASE;
385 return DASM_S_OK;
386 }
387 #undef CK
388
389 /* Get PC label offset. */
dasm_getpclabel(Dst_DECL,unsigned int pc)390 int dasm_getpclabel(Dst_DECL, unsigned int pc)
391 {
392 dasm_State *D = Dst_REF;
393 if (pc*sizeof(int) < D->pcsize) {
394 int pos = D->pclabels[pc];
395 if (pos < 0) return *DASM_POS2PTR(D, -pos);
396 if (pos > 0) return -1; /* Undefined. */
397 }
398 return -2; /* Unused or out of range. */
399 }
400
401 #ifdef DASM_CHECKS
402 /* Optional sanity checker to call between isolated encoding steps. */
dasm_checkstep(Dst_DECL,int secmatch)403 int dasm_checkstep(Dst_DECL, int secmatch)
404 {
405 dasm_State *D = Dst_REF;
406 if (D->status == DASM_S_OK) {
407 int i;
408 for (i = 1; i <= 9; i++) {
409 if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_LG|i; break; }
410 D->lglabels[i] = 0;
411 }
412 }
413 if (D->status == DASM_S_OK && secmatch >= 0 &&
414 D->section != &D->sections[secmatch])
415 D->status = DASM_S_MATCH_SEC|(D->section-D->sections);
416 return D->status;
417 }
418 #endif
419
420
