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1 /**************************************************************************
2  *
3  * Copyright 2009 VMware, Inc.
4  * All Rights Reserved.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the
8  * "Software"), to deal in the Software without restriction, including
9  * without limitation the rights to use, copy, modify, merge, publish,
10  * distribute, sub license, and/or sell copies of the Software, and to
11  * permit persons to whom the Software is furnished to do so, subject to
12  * the following conditions:
13  *
14  * The above copyright notice and this permission notice (including the
15  * next paragraph) shall be included in all copies or substantial portions
16  * of the Software.
17  *
18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21  * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22  * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25  *
26  **************************************************************************/
27 
28 
29 /**
30  * @file
31  * Helper functions for constant building.
32  *
33  * @author Jose Fonseca <jfonseca@vmware.com>
34  */
35 
36 #include <float.h>
37 
38 #include "util/u_debug.h"
39 #include "util/u_math.h"
40 #include "util/u_half.h"
41 
42 #include "lp_bld_type.h"
43 #include "lp_bld_const.h"
44 #include "lp_bld_init.h"
45 
46 
47 unsigned
lp_mantissa(struct lp_type type)48 lp_mantissa(struct lp_type type)
49 {
50    assert(type.floating);
51 
52    if(type.floating) {
53       switch(type.width) {
54       case 16:
55          return 10;
56       case 32:
57          return 23;
58       case 64:
59          return 52;
60       default:
61          assert(0);
62          return 0;
63       }
64    }
65    else {
66       if(type.sign)
67          return type.width - 1;
68       else
69          return type.width;
70    }
71 }
72 
73 
74 /**
75  * Shift of the unity.
76  *
77  * Same as lp_const_scale(), but in terms of shifts.
78  */
79 unsigned
lp_const_shift(struct lp_type type)80 lp_const_shift(struct lp_type type)
81 {
82    if(type.floating)
83       return 0;
84    else if(type.fixed)
85       return type.width/2;
86    else if(type.norm)
87       return type.sign ? type.width - 1 : type.width;
88    else
89       return 0;
90 }
91 
92 
93 unsigned
lp_const_offset(struct lp_type type)94 lp_const_offset(struct lp_type type)
95 {
96    if(type.floating || type.fixed)
97       return 0;
98    else if(type.norm)
99       return 1;
100    else
101       return 0;
102 }
103 
104 
105 /**
106  * Scaling factor between the LLVM native value and its interpretation.
107  *
108  * This is 1.0 for all floating types and unnormalized integers, and something
109  * else for the fixed points types and normalized integers.
110  */
111 double
lp_const_scale(struct lp_type type)112 lp_const_scale(struct lp_type type)
113 {
114    unsigned long long llscale;
115    double dscale;
116 
117    llscale = (unsigned long long)1 << lp_const_shift(type);
118    llscale -= lp_const_offset(type);
119    dscale = (double)llscale;
120    assert((unsigned long long)dscale == llscale);
121 
122    return dscale;
123 }
124 
125 
126 /**
127  * Minimum value representable by the type.
128  */
129 double
lp_const_min(struct lp_type type)130 lp_const_min(struct lp_type type)
131 {
132    unsigned bits;
133 
134    if(!type.sign)
135       return 0.0;
136 
137    if(type.norm)
138       return -1.0;
139 
140    if (type.floating) {
141       switch(type.width) {
142       case 16:
143          return -65504;
144       case 32:
145          return -FLT_MAX;
146       case 64:
147          return -DBL_MAX;
148       default:
149          assert(0);
150          return 0.0;
151       }
152    }
153 
154    if(type.fixed)
155       /* FIXME: consider the fractional bits? */
156       bits = type.width / 2 - 1;
157    else
158       bits = type.width - 1;
159 
160    return (double)-((long long)1 << bits);
161 }
162 
163 
164 /**
165  * Maximum value representable by the type.
166  */
167 double
lp_const_max(struct lp_type type)168 lp_const_max(struct lp_type type)
169 {
170    unsigned bits;
171 
172    if(type.norm)
173       return 1.0;
174 
175    if (type.floating) {
176       switch(type.width) {
177       case 16:
178          return 65504;
179       case 32:
180          return FLT_MAX;
181       case 64:
182          return DBL_MAX;
183       default:
184          assert(0);
185          return 0.0;
186       }
187    }
188 
189    if(type.fixed)
190       bits = type.width / 2;
191    else
192       bits = type.width;
193 
194    if(type.sign)
195       bits -= 1;
196 
197    return (double)(((unsigned long long)1 << bits) - 1);
198 }
199 
200 
201 double
lp_const_eps(struct lp_type type)202 lp_const_eps(struct lp_type type)
203 {
204    if (type.floating) {
205       switch(type.width) {
206       case 16:
207          return 2E-10;
208       case 32:
209          return FLT_EPSILON;
210       case 64:
211          return DBL_EPSILON;
212       default:
213          assert(0);
214          return 0.0;
215       }
216    }
217    else {
218       double scale = lp_const_scale(type);
219       return 1.0/scale;
220    }
221 }
222 
223 
224 LLVMValueRef
lp_build_undef(struct gallivm_state * gallivm,struct lp_type type)225 lp_build_undef(struct gallivm_state *gallivm, struct lp_type type)
226 {
227    LLVMTypeRef vec_type = lp_build_vec_type(gallivm, type);
228    return LLVMGetUndef(vec_type);
229 }
230 
231 
232 LLVMValueRef
lp_build_zero(struct gallivm_state * gallivm,struct lp_type type)233 lp_build_zero(struct gallivm_state *gallivm, struct lp_type type)
234 {
235    if (type.length == 1) {
236       if (type.floating)
237          return lp_build_const_float(gallivm, 0.0);
238       else
239          return LLVMConstInt(LLVMIntTypeInContext(gallivm->context, type.width), 0, 0);
240    }
241    else {
242       LLVMTypeRef vec_type = lp_build_vec_type(gallivm, type);
243       return LLVMConstNull(vec_type);
244    }
245 }
246 
247 
248 LLVMValueRef
lp_build_one(struct gallivm_state * gallivm,struct lp_type type)249 lp_build_one(struct gallivm_state *gallivm, struct lp_type type)
250 {
251    LLVMTypeRef elem_type;
252    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
253    unsigned i;
254 
255    assert(type.length <= LP_MAX_VECTOR_LENGTH);
256 
257    elem_type = lp_build_elem_type(gallivm, type);
258 
259    if(type.floating && type.width == 16)
260       elems[0] = LLVMConstInt(elem_type, util_float_to_half(1.0f), 0);
261    else if(type.floating)
262       elems[0] = LLVMConstReal(elem_type, 1.0);
263    else if(type.fixed)
264       elems[0] = LLVMConstInt(elem_type, 1LL << (type.width/2), 0);
265    else if(!type.norm)
266       elems[0] = LLVMConstInt(elem_type, 1, 0);
267    else if(type.sign)
268       elems[0] = LLVMConstInt(elem_type, (1LL << (type.width - 1)) - 1, 0);
269    else {
270       /* special case' -- 1.0 for normalized types is more easily attained if
271        * we start with a vector consisting of all bits set */
272       LLVMTypeRef vec_type = lp_build_vec_type(gallivm, type);
273       LLVMValueRef vec = LLVMConstAllOnes(vec_type);
274 
275 #if 0
276       if(type.sign)
277          /* TODO: Unfortunately this caused "Tried to create a shift operation
278           * on a non-integer type!" */
279          vec = LLVMConstLShr(vec, lp_build_const_int_vec(type, 1));
280 #endif
281 
282       return vec;
283    }
284 
285    for(i = 1; i < type.length; ++i)
286       elems[i] = elems[0];
287 
288    if (type.length == 1)
289       return elems[0];
290    else
291       return LLVMConstVector(elems, type.length);
292 }
293 
294 
295 /**
296  * Build constant-valued element from a scalar value.
297  */
298 LLVMValueRef
lp_build_const_elem(struct gallivm_state * gallivm,struct lp_type type,double val)299 lp_build_const_elem(struct gallivm_state *gallivm,
300                     struct lp_type type,
301                     double val)
302 {
303    LLVMTypeRef elem_type = lp_build_elem_type(gallivm, type);
304    LLVMValueRef elem;
305 
306    if(type.floating && type.width == 16) {
307       elem = LLVMConstInt(elem_type, util_float_to_half((float)val), 0);
308    } else if(type.floating) {
309       elem = LLVMConstReal(elem_type, val);
310    }
311    else {
312       double dscale = lp_const_scale(type);
313 
314       elem = LLVMConstInt(elem_type, (long long) round(val*dscale), 0);
315    }
316 
317    return elem;
318 }
319 
320 
321 /**
322  * Build constant-valued vector from a scalar value.
323  */
324 LLVMValueRef
lp_build_const_vec(struct gallivm_state * gallivm,struct lp_type type,double val)325 lp_build_const_vec(struct gallivm_state *gallivm, struct lp_type type,
326                    double val)
327 {
328    if (type.length == 1) {
329       return lp_build_const_elem(gallivm, type, val);
330    } else {
331       LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
332       unsigned i;
333       elems[0] = lp_build_const_elem(gallivm, type, val);
334       for(i = 1; i < type.length; ++i)
335          elems[i] = elems[0];
336       return LLVMConstVector(elems, type.length);
337    }
338 }
339 
340 
341 LLVMValueRef
lp_build_const_int_vec(struct gallivm_state * gallivm,struct lp_type type,long long val)342 lp_build_const_int_vec(struct gallivm_state *gallivm, struct lp_type type,
343                        long long val)
344 {
345    LLVMTypeRef elem_type = lp_build_int_elem_type(gallivm, type);
346    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
347    unsigned i;
348 
349    assert(type.length <= LP_MAX_VECTOR_LENGTH);
350 
351    for(i = 0; i < type.length; ++i)
352       elems[i] = LLVMConstInt(elem_type, val, type.sign ? 1 : 0);
353 
354    if (type.length == 1)
355       return elems[0];
356 
357    return LLVMConstVector(elems, type.length);
358 }
359 
360 
361 LLVMValueRef
lp_build_const_aos(struct gallivm_state * gallivm,struct lp_type type,double r,double g,double b,double a,const unsigned char * swizzle)362 lp_build_const_aos(struct gallivm_state *gallivm,
363                    struct lp_type type,
364                    double r, double g, double b, double a,
365                    const unsigned char *swizzle)
366 {
367    const unsigned char default_swizzle[4] = {0, 1, 2, 3};
368    LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
369    unsigned i;
370 
371    assert(type.length % 4 == 0);
372    assert(type.length <= LP_MAX_VECTOR_LENGTH);
373 
374    lp_build_elem_type(gallivm, type);
375 
376    if (!swizzle)
377       swizzle = default_swizzle;
378 
379    elems[swizzle[0]] = lp_build_const_elem(gallivm, type, r);
380    elems[swizzle[1]] = lp_build_const_elem(gallivm, type, g);
381    elems[swizzle[2]] = lp_build_const_elem(gallivm, type, b);
382    elems[swizzle[3]] = lp_build_const_elem(gallivm, type, a);
383 
384    for(i = 4; i < type.length; ++i)
385       elems[i] = elems[i % 4];
386 
387    return LLVMConstVector(elems, type.length);
388 }
389 
390 
391 /**
392  * @param mask TGSI_WRITEMASK_xxx
393  */
394 LLVMValueRef
lp_build_const_mask_aos(struct gallivm_state * gallivm,struct lp_type type,unsigned mask,unsigned channels)395 lp_build_const_mask_aos(struct gallivm_state *gallivm,
396                         struct lp_type type,
397                         unsigned mask,
398                         unsigned channels)
399 {
400    LLVMTypeRef elem_type = LLVMIntTypeInContext(gallivm->context, type.width);
401    LLVMValueRef masks[LP_MAX_VECTOR_LENGTH];
402    unsigned i, j;
403 
404    assert(type.length <= LP_MAX_VECTOR_LENGTH);
405 
406    for (j = 0; j < type.length; j += channels) {
407       for( i = 0; i < channels; ++i) {
408          masks[j + i] = LLVMConstInt(elem_type,
409                                      mask & (1 << i) ? ~0ULL : 0,
410                                      1);
411       }
412    }
413 
414    return LLVMConstVector(masks, type.length);
415 }
416 
417 
418 /**
419  * Performs lp_build_const_mask_aos, but first swizzles the mask
420  */
421 LLVMValueRef
lp_build_const_mask_aos_swizzled(struct gallivm_state * gallivm,struct lp_type type,unsigned mask,unsigned channels,const unsigned char * swizzle)422 lp_build_const_mask_aos_swizzled(struct gallivm_state *gallivm,
423                                  struct lp_type type,
424                                  unsigned mask,
425                                  unsigned channels,
426                                  const unsigned char *swizzle)
427 {
428    unsigned i, mask_swizzled;
429    mask_swizzled = 0;
430 
431    for (i = 0; i < channels; ++i) {
432       if (swizzle[i] < 4) {
433          mask_swizzled |= ((mask & (1 << swizzle[i])) >> swizzle[i]) << i;
434       }
435    }
436 
437    return lp_build_const_mask_aos(gallivm, type, mask_swizzled, channels);
438 }
439 
440 
441 /**
442  * Build a zero-terminated constant string.
443  */
444 LLVMValueRef
lp_build_const_string(struct gallivm_state * gallivm,const char * str)445 lp_build_const_string(struct gallivm_state *gallivm,
446                       const char *str)
447 {
448    unsigned len = strlen(str) + 1;
449    LLVMTypeRef i8 = LLVMInt8TypeInContext(gallivm->context);
450    LLVMValueRef string = LLVMAddGlobal(gallivm->module, LLVMArrayType(i8, len), "");
451    LLVMSetGlobalConstant(string, TRUE);
452    LLVMSetLinkage(string, LLVMInternalLinkage);
453    LLVMSetInitializer(string, LLVMConstStringInContext(gallivm->context, str, len, TRUE));
454    string = LLVMConstBitCast(string, LLVMPointerType(i8, 0));
455    return string;
456 }
457 
458 
459 /**
460  * Build a callable function pointer.
461  *
462  * We use function pointer constants instead of LLVMAddGlobalMapping()
463  * to work around a bug in LLVM 2.6, and for efficiency/simplicity.
464  */
465 LLVMValueRef
lp_build_const_func_pointer(struct gallivm_state * gallivm,const void * ptr,LLVMTypeRef ret_type,LLVMTypeRef * arg_types,unsigned num_args,const char * name)466 lp_build_const_func_pointer(struct gallivm_state *gallivm,
467                             const void *ptr,
468                             LLVMTypeRef ret_type,
469                             LLVMTypeRef *arg_types,
470                             unsigned num_args,
471                             const char *name)
472 {
473    LLVMTypeRef function_type;
474    LLVMValueRef function;
475 
476    function_type = LLVMFunctionType(ret_type, arg_types, num_args, 0);
477 
478    function = lp_build_const_int_pointer(gallivm, ptr);
479 
480    function = LLVMBuildBitCast(gallivm->builder, function,
481                                LLVMPointerType(function_type, 0),
482                                name);
483 
484    return function;
485 }
486