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[ghc.git] / includes / Stg.h
1 /* -----------------------------------------------------------------------------
2 *
3 * (c) The GHC Team, 1998-2009
4 *
5 * Top-level include file for everything required when compiling .hc
6 * code. NOTE: in .hc files, Stg.h must be included *before* any
7 * other headers, because we define some register variables which must
8 * be done before any inline functions are defined (some system
9 * headers have been known to define the odd inline function).
10 *
11 * We generally try to keep as little visible as possible when
12 * compiling .hc files. So for example the definitions of the
13 * InfoTable structs, closure structs and other RTS types are not
14 * visible here. The compiler knows enough about the representations
15 * of these types to generate code which manipulates them directly
16 * with pointer arithmetic.
17 *
18 * In ordinary C code, do not #include this file directly: #include
19 * "Rts.h" instead.
20 *
21 * To understand the structure of the RTS headers, see the wiki:
22 * http://hackage.haskell.org/trac/ghc/wiki/Commentary/SourceTree/Includes
23 *
24 * ---------------------------------------------------------------------------*/
25
26 #ifndef STG_H
27 #define STG_H
28
29 /*
30 * If we are compiling a .hc file, then we want all the register
31 * variables. This is the what happens if you #include "Stg.h" first:
32 * we assume this is a .hc file, and set IN_STG_CODE==1, which later
33 * causes the register variables to be enabled in stg/Regs.h.
34 *
35 * If instead "Rts.h" is included first, then we are compiling a
36 * vanilla C file. Everything from Stg.h is provided, except that
37 * IN_STG_CODE is not defined, and the register variables will not be
38 * active.
39 */
40 #ifndef IN_STG_CODE
41 # define IN_STG_CODE 1
42
43 // Turn on C99 for .hc code. This gives us the INFINITY and NAN
44 // constants from math.h, which we occasionally need to use in .hc (#1861)
45 # define _ISOC99_SOURCE
46
47 // We need _BSD_SOURCE so that math.h defines things like gamma
48 // on Linux
49 # define _BSD_SOURCE
50 #endif
51
52 #if IN_STG_CODE == 0
53 # define NO_GLOBAL_REG_DECLS /* don't define fixed registers */
54 #endif
55
56 /* Configuration */
57 #include "ghcconfig.h"
58
59 /* The code generator calls the math functions directly in .hc code.
60 NB. after configuration stuff above, because this sets #defines
61 that depend on config info, such as __USE_FILE_OFFSET64 */
62 #include <math.h>
63
64 // On Solaris, we don't get the INFINITY and NAN constants unless we
65 // #define _STDC_C99, and we can't do that unless we also use -std=c99,
66 // because _STDC_C99 causes the headers to use C99 syntax (e.g. restrict).
67 // We aren't ready for -std=c99 yet, so define INFINITY/NAN by hand using
68 // the gcc builtins.
69 #if !defined(INFINITY)
70 #if defined(__GNUC__)
71 #define INFINITY __builtin_inf()
72 #else
73 #error No definition for INFINITY
74 #endif
75 #endif
76
77 #if !defined(NAN)
78 #if defined(__GNUC__)
79 #define NAN __builtin_nan("")
80 #else
81 #error No definition for NAN
82 #endif
83 #endif
84
85 /* -----------------------------------------------------------------------------
86 Useful definitions
87 -------------------------------------------------------------------------- */
88
89 /*
90 * The C backend likes to refer to labels by just mentioning their
91 * names. Howevver, when a symbol is declared as a variable in C, the
92 * C compiler will implicitly dereference it when it occurs in source.
93 * So we must subvert this behaviour for .hc files by declaring
94 * variables as arrays, which eliminates the implicit dereference.
95 */
96 #if IN_STG_CODE
97 #define RTS_VAR(x) (x)[]
98 #define RTS_DEREF(x) (*(x))
99 #else
100 #define RTS_VAR(x) x
101 #define RTS_DEREF(x) x
102 #endif
103
104 /* bit macros
105 */
106 #define BITS_PER_BYTE 8
107 #define BITS_IN(x) (BITS_PER_BYTE * sizeof(x))
108
109 /* Compute offsets of struct fields
110 */
111 #define STG_FIELD_OFFSET(s_type, field) ((StgWord)&(((s_type*)0)->field))
112
113 /*
114 * 'Portable' inlining:
115 * INLINE_HEADER is for inline functions in header files (macros)
116 * STATIC_INLINE is for inline functions in source files
117 * EXTERN_INLINE is for functions that we want to inline sometimes
118 * (we also compile a static version of the function; see Inlines.c)
119 */
120 #if defined(__GNUC__) || defined( __INTEL_COMPILER)
121
122 # define INLINE_HEADER static inline
123 # define INLINE_ME inline
124 # define STATIC_INLINE INLINE_HEADER
125
126 // The special "extern inline" behaviour is now only supported by gcc
127 // when _GNUC_GNU_INLINE__ is defined, and you have to use
128 // __attribute__((gnu_inline)). So when we don't have this, we use
129 // ordinary static inline.
130 //
131 // Apple's gcc defines __GNUC_GNU_INLINE__ without providing
132 // gnu_inline, so we exclude MacOS X and fall through to the safe
133 // version.
134 //
135 #if defined(__GNUC_GNU_INLINE__) && !defined(__APPLE__)
136 # if defined(KEEP_INLINES)
137 # define EXTERN_INLINE inline
138 # else
139 # define EXTERN_INLINE extern inline __attribute__((gnu_inline))
140 # endif
141 #else
142 # if defined(KEEP_INLINES)
143 # define EXTERN_INLINE
144 # else
145 # define EXTERN_INLINE INLINE_HEADER
146 # endif
147 #endif
148
149 #elif defined(_MSC_VER)
150
151 # define INLINE_HEADER __inline static
152 # define INLINE_ME __inline
153 # define STATIC_INLINE INLINE_HEADER
154
155 # if defined(KEEP_INLINES)
156 # define EXTERN_INLINE __inline
157 # else
158 # define EXTERN_INLINE __inline extern
159 # endif
160
161 #else
162
163 # error "Don't know how to inline functions with your C compiler."
164
165 #endif
166
167
168 /*
169 * GCC attributes
170 */
171 #if defined(__GNUC__)
172 #define GNU_ATTRIBUTE(at) __attribute__((at))
173 #else
174 #define GNU_ATTRIBUTE(at)
175 #endif
176
177 #if __GNUC__ >= 3
178 #define GNUC3_ATTRIBUTE(at) __attribute__((at))
179 #else
180 #define GNUC3_ATTRIBUTE(at)
181 #endif
182
183 #if __GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 3
184 #define GNUC_ATTR_HOT __attribute__((hot))
185 #else
186 #define GNUC_ATTR_HOT /* nothing */
187 #endif
188
189 #define STG_UNUSED GNUC3_ATTRIBUTE(__unused__)
190
191 /* -----------------------------------------------------------------------------
192 Global type definitions
193 -------------------------------------------------------------------------- */
194
195 #include "MachDeps.h"
196 #include "stg/Types.h"
197
198 /* -----------------------------------------------------------------------------
199 Shorthand forms
200 -------------------------------------------------------------------------- */
201
202 typedef StgChar C_;
203 typedef StgWord W_;
204 typedef StgWord* P_;
205 typedef StgInt I_;
206 typedef StgWord StgWordArray[];
207 typedef StgFunPtr F_;
208
209 #define EI_(X) extern StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
210 #define II_(X) static StgWordArray (X) GNU_ATTRIBUTE(aligned (8))
211 #define IF_(f) static StgFunPtr GNUC3_ATTRIBUTE(used) f(void)
212 #define FN_(f) StgFunPtr f(void)
213 #define EF_(f) extern StgFunPtr f(void)
214
215 /* -----------------------------------------------------------------------------
216 Tail calls
217
218 This needs to be up near the top as the register line on alpha needs
219 to be before all procedures (inline & out-of-line).
220 -------------------------------------------------------------------------- */
221
222 #include "stg/TailCalls.h"
223
224 /* -----------------------------------------------------------------------------
225 Other Stg stuff...
226 -------------------------------------------------------------------------- */
227
228 #include "stg/DLL.h"
229 #include "stg/MachRegs.h"
230 #include "stg/Regs.h"
231 #include "stg/Ticky.h"
232
233 #if IN_STG_CODE
234 /*
235 * This is included later for RTS sources, after definitions of
236 * StgInfoTable, StgClosure and so on.
237 */
238 #include "stg/MiscClosures.h"
239 #endif
240
241 #include "stg/SMP.h" // write_barrier() inline is required
242
243 /* -----------------------------------------------------------------------------
244 Moving Floats and Doubles
245
246 ASSIGN_FLT is for assigning a float to memory (usually the
247 stack/heap). The memory address is guaranteed to be
248 StgWord aligned (currently == sizeof(void *)).
249
250 PK_FLT is for pulling a float out of memory. The memory is
251 guaranteed to be StgWord aligned.
252 -------------------------------------------------------------------------- */
253
254 INLINE_HEADER void ASSIGN_FLT (W_ [], StgFloat);
255 INLINE_HEADER StgFloat PK_FLT (W_ []);
256
257 #if ALIGNMENT_FLOAT <= ALIGNMENT_LONG
258
259 INLINE_HEADER void ASSIGN_FLT(W_ p_dest[], StgFloat src) { *(StgFloat *)p_dest = src; }
260 INLINE_HEADER StgFloat PK_FLT (W_ p_src[]) { return *(StgFloat *)p_src; }
261
262 #else /* ALIGNMENT_FLOAT > ALIGNMENT_UNSIGNED_INT */
263
264 INLINE_HEADER void ASSIGN_FLT(W_ p_dest[], StgFloat src)
265 {
266 float_thing y;
267 y.f = src;
268 *p_dest = y.fu;
269 }
270
271 INLINE_HEADER StgFloat PK_FLT(W_ p_src[])
272 {
273 float_thing y;
274 y.fu = *p_src;
275 return(y.f);
276 }
277
278 #endif /* ALIGNMENT_FLOAT > ALIGNMENT_LONG */
279
280 #if ALIGNMENT_DOUBLE <= ALIGNMENT_LONG
281
282 INLINE_HEADER void ASSIGN_DBL (W_ [], StgDouble);
283 INLINE_HEADER StgDouble PK_DBL (W_ []);
284
285 INLINE_HEADER void ASSIGN_DBL(W_ p_dest[], StgDouble src) { *(StgDouble *)p_dest = src; }
286 INLINE_HEADER StgDouble PK_DBL (W_ p_src[]) { return *(StgDouble *)p_src; }
287
288 #else /* ALIGNMENT_DOUBLE > ALIGNMENT_LONG */
289
290 /* Sparc uses two floating point registers to hold a double. We can
291 * write ASSIGN_DBL and PK_DBL by directly accessing the registers
292 * independently - unfortunately this code isn't writable in C, we
293 * have to use inline assembler.
294 */
295 #if sparc_HOST_ARCH
296
297 #define ASSIGN_DBL(dst0,src) \
298 { StgPtr dst = (StgPtr)(dst0); \
299 __asm__("st %2,%0\n\tst %R2,%1" : "=m" (((P_)(dst))[0]), \
300 "=m" (((P_)(dst))[1]) : "f" (src)); \
301 }
302
303 #define PK_DBL(src0) \
304 ( { StgPtr src = (StgPtr)(src0); \
305 register double d; \
306 __asm__("ld %1,%0\n\tld %2,%R0" : "=f" (d) : \
307 "m" (((P_)(src))[0]), "m" (((P_)(src))[1])); d; \
308 } )
309
310 #else /* ! sparc_HOST_ARCH */
311
312 INLINE_HEADER void ASSIGN_DBL (W_ [], StgDouble);
313 INLINE_HEADER StgDouble PK_DBL (W_ []);
314
315 typedef struct
316 { StgWord dhi;
317 StgWord dlo;
318 } unpacked_double;
319
320 typedef union
321 { StgDouble d;
322 unpacked_double du;
323 } double_thing;
324
325 INLINE_HEADER void ASSIGN_DBL(W_ p_dest[], StgDouble src)
326 {
327 double_thing y;
328 y.d = src;
329 p_dest[0] = y.du.dhi;
330 p_dest[1] = y.du.dlo;
331 }
332
333 /* GCC also works with this version, but it generates
334 the same code as the previous one, and is not ANSI
335
336 #define ASSIGN_DBL( p_dest, src ) \
337 *p_dest = ((double_thing) src).du.dhi; \
338 *(p_dest+1) = ((double_thing) src).du.dlo \
339 */
340
341 INLINE_HEADER StgDouble PK_DBL(W_ p_src[])
342 {
343 double_thing y;
344 y.du.dhi = p_src[0];
345 y.du.dlo = p_src[1];
346 return(y.d);
347 }
348
349 #endif /* ! sparc_HOST_ARCH */
350
351 #endif /* ALIGNMENT_DOUBLE > ALIGNMENT_UNSIGNED_INT */
352
353
354 /* -----------------------------------------------------------------------------
355 Moving 64-bit quantities around
356
357 ASSIGN_Word64 assign an StgWord64/StgInt64 to a memory location
358 PK_Word64 load an StgWord64/StgInt64 from a amemory location
359
360 In both cases the memory location might not be 64-bit aligned.
361 -------------------------------------------------------------------------- */
362
363 #if SIZEOF_HSWORD == 4
364
365 typedef struct
366 { StgWord dhi;
367 StgWord dlo;
368 } unpacked_double_word;
369
370 typedef union
371 { StgInt64 i;
372 unpacked_double_word iu;
373 } int64_thing;
374
375 typedef union
376 { StgWord64 w;
377 unpacked_double_word wu;
378 } word64_thing;
379
380 INLINE_HEADER void ASSIGN_Word64(W_ p_dest[], StgWord64 src)
381 {
382 word64_thing y;
383 y.w = src;
384 p_dest[0] = y.wu.dhi;
385 p_dest[1] = y.wu.dlo;
386 }
387
388 INLINE_HEADER StgWord64 PK_Word64(W_ p_src[])
389 {
390 word64_thing y;
391 y.wu.dhi = p_src[0];
392 y.wu.dlo = p_src[1];
393 return(y.w);
394 }
395
396 INLINE_HEADER void ASSIGN_Int64(W_ p_dest[], StgInt64 src)
397 {
398 int64_thing y;
399 y.i = src;
400 p_dest[0] = y.iu.dhi;
401 p_dest[1] = y.iu.dlo;
402 }
403
404 INLINE_HEADER StgInt64 PK_Int64(W_ p_src[])
405 {
406 int64_thing y;
407 y.iu.dhi = p_src[0];
408 y.iu.dlo = p_src[1];
409 return(y.i);
410 }
411
412 #elif SIZEOF_VOID_P == 8
413
414 INLINE_HEADER void ASSIGN_Word64(W_ p_dest[], StgWord64 src)
415 {
416 p_dest[0] = src;
417 }
418
419 INLINE_HEADER StgWord64 PK_Word64(W_ p_src[])
420 {
421 return p_src[0];
422 }
423
424 INLINE_HEADER void ASSIGN_Int64(W_ p_dest[], StgInt64 src)
425 {
426 p_dest[0] = src;
427 }
428
429 INLINE_HEADER StgInt64 PK_Int64(W_ p_src[])
430 {
431 return p_src[0];
432 }
433
434 #endif /* SIZEOF_HSWORD == 4 */
435
436 /* -----------------------------------------------------------------------------
437 Split markers
438 -------------------------------------------------------------------------- */
439
440 #if defined(USE_SPLIT_MARKERS)
441 #if defined(LEADING_UNDERSCORE)
442 #define __STG_SPLIT_MARKER __asm__("\n___stg_split_marker:");
443 #else
444 #define __STG_SPLIT_MARKER __asm__("\n__stg_split_marker:");
445 #endif
446 #else
447 #define __STG_SPLIT_MARKER /* nothing */
448 #endif
449
450 /* -----------------------------------------------------------------------------
451 Write-combining store
452 -------------------------------------------------------------------------- */
453
454 INLINE_HEADER void
455 wcStore (StgPtr p, StgWord w)
456 {
457 #ifdef x86_64_HOST_ARCH
458 __asm__(
459 "movnti\t%1, %0"
460 : "=m" (*p)
461 : "r" (w)
462 );
463 #else
464 *p = w;
465 #endif
466 }
467
468 /* -----------------------------------------------------------------------------
469 Integer multiply with overflow
470 -------------------------------------------------------------------------- */
471
472 /* Multiply with overflow checking.
473 *
474 * This is tricky - the usual sign rules for add/subtract don't apply.
475 *
476 * On 32-bit machines we use gcc's 'long long' types, finding
477 * overflow with some careful bit-twiddling.
478 *
479 * On 64-bit machines where gcc's 'long long' type is also 64-bits,
480 * we use a crude approximation, testing whether either operand is
481 * larger than 32-bits; if neither is, then we go ahead with the
482 * multiplication.
483 *
484 * Return non-zero if there is any possibility that the signed multiply
485 * of a and b might overflow. Return zero only if you are absolutely sure
486 * that it won't overflow. If in doubt, return non-zero.
487 */
488
489 #if SIZEOF_VOID_P == 4
490
491 #ifdef WORDS_BIGENDIAN
492 #define RTS_CARRY_IDX__ 0
493 #define RTS_REM_IDX__ 1
494 #else
495 #define RTS_CARRY_IDX__ 1
496 #define RTS_REM_IDX__ 0
497 #endif
498
499 typedef union {
500 StgInt64 l;
501 StgInt32 i[2];
502 } long_long_u ;
503
504 #define mulIntMayOflo(a,b) \
505 ({ \
506 StgInt32 r, c; \
507 long_long_u z; \
508 z.l = (StgInt64)a * (StgInt64)b; \
509 r = z.i[RTS_REM_IDX__]; \
510 c = z.i[RTS_CARRY_IDX__]; \
511 if (c == 0 || c == -1) { \
512 c = ((StgWord)((a^b) ^ r)) \
513 >> (BITS_IN (I_) - 1); \
514 } \
515 c; \
516 })
517
518 /* Careful: the carry calculation above is extremely delicate. Make sure
519 * you test it thoroughly after changing it.
520 */
521
522 #else
523
524 /* Approximate version when we don't have long arithmetic (on 64-bit archs) */
525
526 /* If we have n-bit words then we have n-1 bits after accounting for the
527 * sign bit, so we can fit the result of multiplying 2 (n-1)/2-bit numbers */
528 #define HALF_POS_INT (((I_)1) << ((BITS_IN (I_) - 1) / 2))
529 #define HALF_NEG_INT (-HALF_POS_INT)
530
531 #define mulIntMayOflo(a,b) \
532 ({ \
533 I_ c; \
534 if ((I_)a <= HALF_NEG_INT || a >= HALF_POS_INT \
535 || (I_)b <= HALF_NEG_INT || b >= HALF_POS_INT) {\
536 c = 1; \
537 } else { \
538 c = 0; \
539 } \
540 c; \
541 })
542 #endif
543
544 #endif /* STG_H */