src/mesa/shader/slang/slang_emit.c

   1 /*
   2  * Mesa 3-D graphics library
   3  * Version:  6.5.3
   4  *
   5  * Copyright (C) 2005-2007  Brian Paul   All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  21  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  22  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  23  */
  24
  25 /**
  26  * \file slang_emit.c
  27  * Emit program instructions (PI code) from IR trees.
  28  * \author Brian Paul
  29  */
  30
  31 #include "imports.h"
  32 #include "context.h"
  33 #include "macros.h"
  34 #include "program.h"
  35 #include "prog_instruction.h"
  36 #include "prog_parameter.h"
  37 #include "prog_print.h"
  38 #include "slang_emit.h"
  39 #include "slang_error.h"
  40
  41
  42 #define PEEPHOLE_OPTIMIZATIONS 1
  43 #define ANNOTATE 1
  44
  45
  46 /**
  47  * Assembly and IR info
  48  */
  49 typedef struct
  50 {
  51    slang_ir_opcode IrOpcode;
  52    const char *IrName;
  53    gl_inst_opcode InstOpcode;
  54    GLuint ResultSize, NumParams;
  55 } slang_ir_info;
  56
  57
  58
  59 static slang_ir_info IrInfo[] = {
  60    /* binary ops */
  61    { IR_ADD, "IR_ADD", OPCODE_ADD, 4, 2 },
  62    { IR_SUB, "IR_SUB", OPCODE_SUB, 4, 2 },
  63    { IR_MUL, "IR_MUL", OPCODE_MUL, 4, 2 },
  64    { IR_DIV, "IR_DIV", OPCODE_NOP, 0, 2 }, /* XXX broke */
  65    { IR_DOT4, "IR_DOT_4", OPCODE_DP4, 1, 2 },
  66    { IR_DOT3, "IR_DOT_3", OPCODE_DP3, 1, 2 },
  67    { IR_CROSS, "IR_CROSS", OPCODE_XPD, 3, 2 },
  68    { IR_LRP, "IR_LRP", OPCODE_LRP, 4, 3 },
  69    { IR_MIN, "IR_MIN", OPCODE_MIN, 4, 2 },
  70    { IR_MAX, "IR_MAX", OPCODE_MAX, 4, 2 },
  71    { IR_CLAMP, "IR_CLAMP", OPCODE_NOP, 4, 3 }, /* special case: emit_clamp() */
  72    { IR_SEQUAL, "IR_SEQUAL", OPCODE_SEQ, 4, 2 },
  73    { IR_SNEQUAL, "IR_SNEQUAL", OPCODE_SNE, 4, 2 },
  74    { IR_SGE, "IR_SGE", OPCODE_SGE, 4, 2 },
  75    { IR_SGT, "IR_SGT", OPCODE_SGT, 4, 2 },
  76    { IR_POW, "IR_POW", OPCODE_POW, 1, 2 },
  77    /* unary ops */
  78    { IR_I_TO_F, "IR_I_TO_F", OPCODE_NOP, 1, 1 },
  79    { IR_F_TO_I, "IR_F_TO_I", OPCODE_INT, 4, 1 }, /* 4 floats to 4 ints */
  80    { IR_EXP, "IR_EXP", OPCODE_EXP, 1, 1 },
  81    { IR_EXP2, "IR_EXP2", OPCODE_EX2, 1, 1 },
  82    { IR_LOG2, "IR_LOG2", OPCODE_LG2, 1, 1 },
  83    { IR_RSQ, "IR_RSQ", OPCODE_RSQ, 1, 1 },
  84    { IR_RCP, "IR_RCP", OPCODE_RCP, 1, 1 },
  85    { IR_FLOOR, "IR_FLOOR", OPCODE_FLR, 4, 1 },
  86    { IR_FRAC, "IR_FRAC", OPCODE_FRC, 4, 1 },
  87    { IR_ABS, "IR_ABS", OPCODE_ABS, 4, 1 },
  88    { IR_NEG, "IR_NEG", OPCODE_NOP, 4, 1 }, /* special case: emit_negation() */
  89    { IR_DDX, "IR_DDX", OPCODE_DDX, 4, 1 },
  90    { IR_DDX, "IR_DDY", OPCODE_DDX, 4, 1 },
  91    { IR_SIN, "IR_SIN", OPCODE_SIN, 1, 1 },
  92    { IR_COS, "IR_COS", OPCODE_COS, 1, 1 },
  93    { IR_NOISE1, "IR_NOISE1", OPCODE_NOISE1, 1, 1 },
  94    { IR_NOISE2, "IR_NOISE2", OPCODE_NOISE2, 1, 1 },
  95    { IR_NOISE3, "IR_NOISE3", OPCODE_NOISE3, 1, 1 },
  96    { IR_NOISE4, "IR_NOISE4", OPCODE_NOISE4, 1, 1 },
  97
  98    /* other */
  99    { IR_SEQ, "IR_SEQ", OPCODE_NOP, 0, 0 },
 100    { IR_SCOPE, "IR_SCOPE", OPCODE_NOP, 0, 0 },
 101    { IR_LABEL, "IR_LABEL", OPCODE_NOP, 0, 0 },
 102    { IR_JUMP, "IR_JUMP", OPCODE_NOP, 0, 0 },
 103    { IR_CJUMP0, "IR_CJUMP0", OPCODE_NOP, 0, 0 },
 104    { IR_CJUMP1, "IR_CJUMP1", OPCODE_NOP, 0, 0 },
 105    { IR_IF, "IR_IF", OPCODE_NOP, 0, 0 },
 106    { IR_ELSE, "IR_ELSE", OPCODE_NOP, 0, 0 },
 107    { IR_ENDIF, "IR_ENDIF", OPCODE_NOP, 0, 0 },
 108    { IR_KILL, "IR_KILL", OPCODE_NOP, 0, 0 },
 109    { IR_COND, "IR_COND", OPCODE_NOP, 0, 0 },
 110    { IR_CALL, "IR_CALL", OPCODE_NOP, 0, 0 },
 111    { IR_MOVE, "IR_MOVE", OPCODE_NOP, 0, 1 },
 112    { IR_NOT, "IR_NOT", OPCODE_NOP, 1, 1 },
 113    { IR_VAR, "IR_VAR", OPCODE_NOP, 0, 0 },
 114    { IR_VAR_DECL, "IR_VAR_DECL", OPCODE_NOP, 0, 0 },
 115    { IR_TEX, "IR_TEX", OPCODE_TEX, 4, 1 },
 116    { IR_TEXB, "IR_TEXB", OPCODE_TXB, 4, 1 },
 117    { IR_TEXP, "IR_TEXP", OPCODE_TXP, 4, 1 },
 118    { IR_FLOAT, "IR_FLOAT", OPCODE_NOP, 0, 0 },
 119    { IR_FIELD, "IR_FIELD", OPCODE_NOP, 0, 0 },
 120    { IR_ELEMENT, "IR_ELEMENT", OPCODE_NOP, 0, 0 },
 121    { IR_SWIZZLE, "IR_SWIZZLE", OPCODE_NOP, 0, 0 },
 122    { IR_NOP, NULL, OPCODE_NOP, 0, 0 }
 123 };
 124
 125
 126 static slang_ir_info *
 127 slang_find_ir_info(slang_ir_opcode opcode)
 128 {
 129    GLuint i;
 130    for (i = 0; IrInfo[i].IrName; i++) {
 131       if (IrInfo[i].IrOpcode == opcode) {
 132          return IrInfo + i;
 133       }
 134    }
 135    return NULL;
 136 }
 137
 138 static const char *
 139 slang_ir_name(slang_ir_opcode opcode)
 140 {
 141    return slang_find_ir_info(opcode)->IrName;
 142 }
 143
 144
 145 /**
 146  * Swizzle a swizzle.  That is, return swz2(swz1)
 147  */
 148 static GLuint
 149 swizzle_swizzle(GLuint swz1, GLuint swz2)
 150 {
 151    GLuint i, swz, s[4];
 152    for (i = 0; i < 4; i++) {
 153       GLuint c = GET_SWZ(swz2, i);
 154       s[i] = GET_SWZ(swz1, c);
 155    }
 156    swz = MAKE_SWIZZLE4(s[0], s[1], s[2], s[3]);
 157    return swz;
 158 }
 159
 160
 161 slang_ir_storage *
 162 _slang_new_ir_storage(enum register_file file, GLint index, GLint size)
 163 {
 164    slang_ir_storage *st;
 165    st = (slang_ir_storage *) _mesa_calloc(sizeof(slang_ir_storage));
 166    if (st) {
 167       st->File = file;
 168       st->Index = index;
 169       st->Size = size;
 170       st->Swizzle = SWIZZLE_NOOP;
 171    }
 172    return st;
 173 }
 174
 175
 176 static const char *
 177 swizzle_string(GLuint swizzle)
 178 {
 179    static char s[6];
 180    GLuint i;
 181    s[0] = '.';
 182    for (i = 1; i < 5; i++) {
 183       s[i] = "xyzw"[GET_SWZ(swizzle, i-1)];
 184    }
 185    s[i] = 0;
 186    return s;
 187 }
 188
 189 static const char *
 190 writemask_string(GLuint writemask)
 191 {
 192    static char s[6];
 193    GLuint i, j = 0;
 194    s[j++] = '.';
 195    for (i = 0; i < 4; i++) {
 196       if (writemask & (1 << i))
 197          s[j++] = "xyzw"[i];
 198    }
 199    s[j] = 0;
 200    return s;
 201 }
 202
 203 static const char *
 204 storage_string(const slang_ir_storage *st)
 205 {
 206    static const char *files[] = {
 207       "TEMP",
 208       "LOCAL_PARAM",
 209       "ENV_PARAM",
 210       "STATE",
 211       "INPUT",
 212       "OUTPUT",
 213       "NAMED_PARAM",
 214       "CONSTANT",
 215       "UNIFORM",
 216       "WRITE_ONLY",
 217       "ADDRESS",
 218       "SAMPLER",
 219       "UNDEFINED"
 220    };
 221    static char s[100];
 222 #if 0
 223    if (st->Size == 1)
 224       sprintf(s, "%s[%d]", files[st->File], st->Index);
 225    else
 226       sprintf(s, "%s[%d..%d]", files[st->File], st->Index,
 227               st->Index + st->Size - 1);
 228 #endif
 229    assert(st->File < (GLint) (sizeof(files) / sizeof(files[0])));
 230    sprintf(s, "%s[%d]", files[st->File], st->Index);
 231    return s;
 232 }
 233
 234
 235 #define IND 0
 236 void
 237 slang_print_ir(const slang_ir_node *n, int indent)
 238 {
 239    int i;
 240    if (!n)
 241       return;
 242 #if !IND
 243    if (n->Opcode != IR_SEQ)
 244 #else
 245       printf("%3d:", indent);
 246 #endif
 247       for (i = 0; i < indent; i++)
 248          printf(" ");
 249
 250    switch (n->Opcode) {
 251    case IR_SEQ:
 252 #if IND
 253       printf("SEQ  at %p\n", (void*) n);
 254 #endif
 255       assert(n->Children[0]);
 256       assert(n->Children[1]);
 257       slang_print_ir(n->Children[0], indent + IND);
 258       slang_print_ir(n->Children[1], indent + IND);
 259       break;
 260    case IR_SCOPE:
 261       printf("NEW SCOPE\n");
 262       assert(!n->Children[1]);
 263       slang_print_ir(n->Children[0], indent + 3);
 264       break;
 265    case IR_MOVE:
 266       printf("MOVE (writemask = %s)\n", writemask_string(n->Writemask));
 267       slang_print_ir(n->Children[0], indent+3);
 268       slang_print_ir(n->Children[1], indent+3);
 269       break;
 270    case IR_LABEL:
 271       printf("LABEL: %s\n", n->Target);
 272       break;
 273    case IR_COND:
 274       printf("COND\n");
 275       slang_print_ir(n->Children[0], indent + 3);
 276       break;
 277    case IR_JUMP:
 278       printf("JUMP %s\n", n->Target);
 279       break;
 280    case IR_CJUMP0:
 281       printf("CJUMP0 %s\n", n->Target);
 282       slang_print_ir(n->Children[0], indent+3);
 283       break;
 284    case IR_CJUMP1:
 285       printf("CJUMP1 %s\n", n->Target);
 286       slang_print_ir(n->Children[0], indent+3);
 287       break;
 288
 289    case IR_IF:
 290       printf("IF \n");
 291       slang_print_ir(n->Children[0], indent+3);
 292       break;
 293    case IR_ELSE:
 294       printf("ELSE\n");
 295       break;
 296    case IR_ENDIF:
 297       printf("ENDIF\n");
 298       break;
 299
 300    case IR_VAR:
 301       printf("VAR %s%s at %s  store %p\n",
 302              (n->Var ? (char *) n->Var->a_name : "TEMP"),
 303              swizzle_string(n->Store->Swizzle),
 304              storage_string(n->Store), (void*) n->Store);
 305       break;
 306    case IR_VAR_DECL:
 307       printf("VAR_DECL %s (%p) at %s  store %p\n",
 308              (n->Var ? (char *) n->Var->a_name : "TEMP"),
 309              (void*) n->Var, storage_string(n->Store),
 310              (void*) n->Store);
 311       break;
 312    case IR_FIELD:
 313       printf("FIELD %s of\n", n->Target);
 314       slang_print_ir(n->Children[0], indent+3);
 315       break;
 316    case IR_CALL:
 317       printf("ASMCALL %s(%d args)\n", n->Target, 0/*XXX*/);
 318       break;
 319    case IR_FLOAT:
 320       printf("FLOAT %f %f %f %f\n",
 321              n->Value[0], n->Value[1], n->Value[2], n->Value[3]);
 322       break;
 323    case IR_I_TO_F:
 324       printf("INT_TO_FLOAT %d\n", (int) n->Value[0]);
 325       break;
 326    case IR_SWIZZLE:
 327       printf("SWIZZLE %s of  (store %p) \n",
 328              swizzle_string(n->Store->Swizzle), (void*) n->Store);
 329       slang_print_ir(n->Children[0], indent + 3);
 330       break;
 331    default:
 332       printf("%s (%p, %p)  (store %p)\n", slang_ir_name(n->Opcode),
 333              (void*) n->Children[0], (void*) n->Children[1], (void*) n->Store);
 334       slang_print_ir(n->Children[0], indent+3);
 335       slang_print_ir(n->Children[1], indent+3);
 336    }
 337 }
 338
 339
 340 /**
 341  * Allocate temporary storage for an intermediate result (such as for
 342  * a multiply or add, etc.
 343  */
 344 static GLboolean
 345 alloc_temp_storage(slang_var_table *vt, slang_ir_node *n, GLint size)
 346 {
 347    assert(!n->Var);
 348    assert(!n->Store);
 349    assert(size > 0);
 350    n->Store = _slang_new_ir_storage(PROGRAM_TEMPORARY, -1, size);
 351    if (!_slang_alloc_temp(vt, n->Store)) {
 352       RETURN_ERROR("Ran out of registers, too many temporaries", 0);
 353    }
 354    return GL_TRUE;
 355 }
 356
 357
 358 /**
 359  * Free temporary storage, if n->Store is, in fact, temp storage.
 360  * Otherwise, no-op.
 361  */
 362 static void
 363 free_temp_storage(slang_var_table *vt, slang_ir_node *n)
 364 {
 365    if (n->Store->File == PROGRAM_TEMPORARY && n->Store->Index >= 0) {
 366       if (_slang_is_temp(vt, n->Store)) {
 367          _slang_free_temp(vt, n->Store);
 368          n->Store->Index = -1;
 369          n->Store->Size = -1;
 370       }
 371    }
 372 }
 373
 374
 375 /**
 376  * Convert IR storage to an instruction dst register.
 377  */
 378 static void
 379 storage_to_dst_reg(struct prog_dst_register *dst, const slang_ir_storage *st,
 380                    GLuint writemask)
 381 {
 382    static const GLuint defaultWritemask[4] = {
 383       WRITEMASK_X,
 384       WRITEMASK_X | WRITEMASK_Y,
 385       WRITEMASK_X | WRITEMASK_Y | WRITEMASK_Z,
 386       WRITEMASK_X | WRITEMASK_Y | WRITEMASK_Z | WRITEMASK_W
 387    };
 388    assert(st->Index >= 0 && st->Index <= 16);
 389    dst->File = st->File;
 390    dst->Index = st->Index;
 391    assert(st->File != PROGRAM_UNDEFINED);
 392    assert(st->Size >= 1);
 393    assert(st->Size <= 4);
 394    if (st->Size == 1) {
 395       GLuint comp = GET_SWZ(st->Swizzle, 0);
 396       assert(comp < 4);
 397       assert(writemask & WRITEMASK_X);
 398       dst->WriteMask = WRITEMASK_X << comp;
 399    }
 400    else {
 401       dst->WriteMask = defaultWritemask[st->Size - 1] & writemask;
 402    }
 403 }
 404
 405
 406 /**
 407  * Convert IR storage to an instruction src register.
 408  */
 409 static void
 410 storage_to_src_reg(struct prog_src_register *src, const slang_ir_storage *st)
 411 {
 412    static const GLuint defaultSwizzle[4] = {
 413       MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_X, SWIZZLE_X, SWIZZLE_X),
 414       MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_W),
 415       MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_W),
 416       MAKE_SWIZZLE4(SWIZZLE_X, SWIZZLE_Y, SWIZZLE_Z, SWIZZLE_W)
 417    };
 418    assert(st->File >= 0 && st->File <= 16);
 419    src->File = st->File;
 420    src->Index = st->Index;
 421    assert(st->File != PROGRAM_UNDEFINED);
 422    assert(st->Size >= 1);
 423    assert(st->Size <= 4);
 424    if (st->Swizzle != SWIZZLE_NOOP)
 425       src->Swizzle = st->Swizzle;
 426    else
 427       src->Swizzle = defaultSwizzle[st->Size - 1]; /*XXX really need this?*/
 428
 429    assert(GET_SWZ(src->Swizzle, 0) != SWIZZLE_NIL);
 430    assert(GET_SWZ(src->Swizzle, 1) != SWIZZLE_NIL);
 431    assert(GET_SWZ(src->Swizzle, 2) != SWIZZLE_NIL);
 432    assert(GET_SWZ(src->Swizzle, 3) != SWIZZLE_NIL);
 433 }
 434
 435
 436
 437 /**
 438  * Add new instruction at end of given program.
 439  * \param prog  the program to append instruction onto
 440  * \param opcode  opcode for the new instruction
 441  * \return pointer to the new instruction
 442  */
 443 static struct prog_instruction *
 444 new_instruction(struct gl_program *prog, gl_inst_opcode opcode)
 445 {
 446    struct prog_instruction *inst;
 447    prog->Instructions = _mesa_realloc_instructions(prog->Instructions,
 448                                                    prog->NumInstructions,
 449                                                    prog->NumInstructions + 1);
 450    inst = prog->Instructions + prog->NumInstructions;
 451    prog->NumInstructions++;
 452    _mesa_init_instructions(inst, 1);
 453    inst->Opcode = opcode;
 454    return inst;
 455 }
 456
 457
 458 /**
 459  * Return pointer to last instruction in program.
 460  */
 461 static struct prog_instruction *
 462 prev_instruction(struct gl_program *prog)
 463 {
 464    if (prog->NumInstructions == 0)
 465       return NULL;
 466    else
 467       return prog->Instructions + prog->NumInstructions - 1;
 468 }
 469
 470
 471 static struct prog_instruction *
 472 emit(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog);
 473
 474
 475 /**
 476  * Return an annotation string for given node's storage.
 477  */
 478 static char *
 479 storage_annotation(const slang_ir_node *n, const struct gl_program *prog)
 480 {
 481 #if ANNOTATE
 482    const slang_ir_storage *st = n->Store;
 483    static char s[100] = "";
 484
 485    if (!st)
 486       return _mesa_strdup("");
 487
 488    switch (st->File) {
 489    case PROGRAM_CONSTANT:
 490       if (st->Index >= 0) {
 491          const GLfloat *val = prog->Parameters->ParameterValues[st->Index];
 492          if (st->Swizzle == SWIZZLE_NOOP)
 493             sprintf(s, "{%f, %f, %f, %f}", val[0], val[1], val[2], val[3]);
 494          else {
 495             sprintf(s, "%f", val[GET_SWZ(st->Swizzle, 0)]);
 496          }
 497       }
 498       break;
 499    case PROGRAM_TEMPORARY:
 500       if (n->Var)
 501          sprintf(s, "%s", (char *) n->Var->a_name);
 502       else
 503          sprintf(s, "t[%d]", st->Index);
 504       break;
 505    case PROGRAM_STATE_VAR:
 506    case PROGRAM_UNIFORM:
 507       sprintf(s, "%s", prog->Parameters->Parameters[st->Index].Name);
 508       break;
 509    case PROGRAM_VARYING:
 510       sprintf(s, "%s", prog->Varying->Parameters[st->Index].Name);
 511       break;
 512    case PROGRAM_INPUT:
 513       sprintf(s, "input[%d]", st->Index);
 514       break;
 515    case PROGRAM_OUTPUT:
 516       sprintf(s, "output[%d]", st->Index);
 517       break;
 518    default:
 519       s[0] = 0;
 520    }
 521    return _mesa_strdup(s);
 522 #else
 523    return NULL;
 524 #endif
 525 }
 526
 527
 528 /**
 529  * Return an annotation string for an instruction.
 530  */
 531 static char *
 532 instruction_annotation(gl_inst_opcode opcode, char *dstAnnot,
 533                        char *srcAnnot0, char *srcAnnot1, char *srcAnnot2)
 534 {
 535 #if ANNOTATE
 536    const char *operator;
 537    char *s;
 538    int len = 50;
 539
 540    if (dstAnnot)
 541       len += strlen(dstAnnot);
 542    else
 543       dstAnnot = _mesa_strdup("");
 544
 545    if (srcAnnot0)
 546       len += strlen(srcAnnot0);
 547    else
 548       srcAnnot0 = _mesa_strdup("");
 549
 550    if (srcAnnot1)
 551       len += strlen(srcAnnot1);
 552    else
 553       srcAnnot1 = _mesa_strdup("");
 554
 555    if (srcAnnot2)
 556       len += strlen(srcAnnot2);
 557    else
 558       srcAnnot2 = _mesa_strdup("");
 559
 560    switch (opcode) {
 561    case OPCODE_ADD:
 562       operator = "+";
 563       break;
 564    case OPCODE_SUB:
 565       operator = "-";
 566       break;
 567    case OPCODE_MUL:
 568       operator = "*";
 569       break;
 570    case OPCODE_DP3:
 571       operator = "DP3";
 572       break;
 573    case OPCODE_DP4:
 574       operator = "DP4";
 575       break;
 576    case OPCODE_XPD:
 577       operator = "XPD";
 578       break;
 579    case OPCODE_RSQ:
 580       operator = "RSQ";
 581       break;
 582    case OPCODE_SGT:
 583       operator = ">";
 584       break;
 585    default:
 586       operator = ",";
 587    }
 588
 589    s = (char *) malloc(len);
 590    sprintf(s, "%s = %s %s %s %s", dstAnnot,
 591            srcAnnot0, operator, srcAnnot1, srcAnnot2);
 592    assert(_mesa_strlen(s) < len);
 593
 594    free(dstAnnot);
 595    free(srcAnnot0);
 596    free(srcAnnot1);
 597    free(srcAnnot2);
 598
 599    return s;
 600 #else
 601    return NULL;
 602 #endif
 603 }
 604
 605
 606
 607 /**
 608  * Generate code for a simple arithmetic instruction.
 609  * Either 1, 2 or 3 operands.
 610  */
 611 static struct prog_instruction *
 612 emit_arith(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 613 {
 614    struct prog_instruction *inst;
 615    const slang_ir_info *info = slang_find_ir_info(n->Opcode);
 616    char *srcAnnot[3], *dstAnnot;
 617    GLuint i;
 618
 619    assert(info);
 620    assert(info->InstOpcode != OPCODE_NOP);
 621
 622    srcAnnot[0] = srcAnnot[1] = srcAnnot[2] = dstAnnot = NULL;
 623
 624 #if PEEPHOLE_OPTIMIZATIONS
 625    /* Look for MAD opportunity */
 626    if (info->NumParams == 2 &&
 627        n->Opcode == IR_ADD && n->Children[0]->Opcode == IR_MUL) {
 628       /* found pattern IR_ADD(IR_MUL(A, B), C) */
 629       emit(vt, n->Children[0]->Children[0], prog);  /* A */
 630       emit(vt, n->Children[0]->Children[1], prog);  /* B */
 631       emit(vt, n->Children[1], prog);  /* C */
 632       /* generate MAD instruction */
 633       inst = new_instruction(prog, OPCODE_MAD);
 634       /* operands: A, B, C: */
 635       storage_to_src_reg(&inst->SrcReg[0], n->Children[0]->Children[0]->Store);
 636       storage_to_src_reg(&inst->SrcReg[1], n->Children[0]->Children[1]->Store);
 637       storage_to_src_reg(&inst->SrcReg[2], n->Children[1]->Store);
 638       free_temp_storage(vt, n->Children[0]->Children[0]);
 639       free_temp_storage(vt, n->Children[0]->Children[1]);
 640       free_temp_storage(vt, n->Children[1]);
 641    }
 642    else if (info->NumParams == 2 &&
 643             n->Opcode == IR_ADD && n->Children[1]->Opcode == IR_MUL) {
 644       /* found pattern IR_ADD(A, IR_MUL(B, C)) */
 645       emit(vt, n->Children[0], prog);  /* A */
 646       emit(vt, n->Children[1]->Children[0], prog);  /* B */
 647       emit(vt, n->Children[1]->Children[1], prog);  /* C */
 648       /* generate MAD instruction */
 649       inst = new_instruction(prog, OPCODE_MAD);
 650       /* operands: B, C, A */
 651       storage_to_src_reg(&inst->SrcReg[0], n->Children[1]->Children[0]->Store);
 652       storage_to_src_reg(&inst->SrcReg[1], n->Children[1]->Children[1]->Store);
 653       storage_to_src_reg(&inst->SrcReg[2], n->Children[0]->Store);
 654       free_temp_storage(vt, n->Children[1]->Children[0]);
 655       free_temp_storage(vt, n->Children[1]->Children[1]);
 656       free_temp_storage(vt, n->Children[0]);
 657    }
 658    else
 659 #endif
 660    {
 661       /* normal case */
 662
 663       /* gen code for children */
 664       for (i = 0; i < info->NumParams; i++)
 665          emit(vt, n->Children[i], prog);
 666
 667       /* gen this instruction and src registers */
 668       inst = new_instruction(prog, info->InstOpcode);
 669       for (i = 0; i < info->NumParams; i++)
 670          storage_to_src_reg(&inst->SrcReg[i], n->Children[i]->Store);
 671
 672       /* annotation */
 673       for (i = 0; i < info->NumParams; i++)
 674          srcAnnot[i] = storage_annotation(n->Children[i], prog);
 675
 676       /* free temps */
 677       for (i = 0; i < info->NumParams; i++)
 678          free_temp_storage(vt, n->Children[i]);
 679    }
 680
 681    /* result storage */
 682    if (!n->Store) {
 683       if (!alloc_temp_storage(vt, n, info->ResultSize))
 684          return NULL;
 685    }
 686    storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 687
 688    dstAnnot = storage_annotation(n, prog);
 689
 690    inst->Comment = instruction_annotation(inst->Opcode, dstAnnot, srcAnnot[0],
 691                                           srcAnnot[1], srcAnnot[2]);
 692
 693    /*_mesa_print_instruction(inst);*/
 694    return inst;
 695 }
 696
 697
 698 /**
 699  * Generate code for an IR_CLAMP instruction.
 700  */
 701 static struct prog_instruction *
 702 emit_clamp(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 703 {
 704    struct prog_instruction *inst;
 705
 706    assert(n->Opcode == IR_CLAMP);
 707    /* ch[0] = value
 708     * ch[1] = min limit
 709     * ch[2] = max limit
 710     */
 711
 712    inst = emit(vt, n->Children[0], prog);
 713
 714    /* If lower limit == 0.0 and upper limit == 1.0,
 715     *    set prev instruction's SaturateMode field to SATURATE_ZERO_ONE.
 716     * Else,
 717     *    emit OPCODE_MIN, OPCODE_MAX sequence.
 718     */
 719 #if 0
 720    /* XXX this isn't quite finished yet */
 721    if (n->Children[1]->Opcode == IR_FLOAT &&
 722        n->Children[1]->Value[0] == 0.0 &&
 723        n->Children[1]->Value[1] == 0.0 &&
 724        n->Children[1]->Value[2] == 0.0 &&
 725        n->Children[1]->Value[3] == 0.0 &&
 726        n->Children[2]->Opcode == IR_FLOAT &&
 727        n->Children[2]->Value[0] == 1.0 &&
 728        n->Children[2]->Value[1] == 1.0 &&
 729        n->Children[2]->Value[2] == 1.0 &&
 730        n->Children[2]->Value[3] == 1.0) {
 731       if (!inst) {
 732          inst = prev_instruction(prog);
 733       }
 734       if (inst && inst->Opcode != OPCODE_NOP) {
 735          /* and prev instruction's DstReg matches n->Children[0]->Store */
 736          inst->SaturateMode = SATURATE_ZERO_ONE;
 737          n->Store = n->Children[0]->Store;
 738          return inst;
 739       }
 740    }
 741 #endif
 742
 743    if (!n->Store)
 744       if (!alloc_temp_storage(vt, n, n->Children[0]->Store->Size))
 745          return NULL;
 746
 747    emit(vt, n->Children[1], prog);
 748    emit(vt, n->Children[2], prog);
 749
 750    /* tmp = max(ch[0], ch[1]) */
 751    inst = new_instruction(prog, OPCODE_MAX);
 752    storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 753    storage_to_src_reg(&inst->SrcReg[0], n->Children[0]->Store);
 754    storage_to_src_reg(&inst->SrcReg[1], n->Children[1]->Store);
 755
 756    /* tmp = min(tmp, ch[2]) */
 757    inst = new_instruction(prog, OPCODE_MIN);
 758    storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 759    storage_to_src_reg(&inst->SrcReg[0], n->Store);
 760    storage_to_src_reg(&inst->SrcReg[1], n->Children[2]->Store);
 761
 762    return inst;
 763 }
 764
 765
 766 static struct prog_instruction *
 767 emit_negation(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 768 {
 769    /* Implement as MOV dst, -src; */
 770    /* XXX we could look at the previous instruction and in some circumstances
 771     * modify it to accomplish the negation.
 772     */
 773    struct prog_instruction *inst;
 774
 775    emit(vt, n->Children[0], prog);
 776
 777    if (!n->Store)
 778       if (!alloc_temp_storage(vt, n, n->Children[0]->Store->Size))
 779          return NULL;
 780
 781    inst = new_instruction(prog, OPCODE_MOV);
 782    storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 783    storage_to_src_reg(&inst->SrcReg[0], n->Children[0]->Store);
 784    inst->SrcReg[0].NegateBase = NEGATE_XYZW;
 785    inst->Comment = n->Comment;
 786    return inst;
 787 }
 788
 789
 790 static struct prog_instruction *
 791 emit_label(const char *target, struct gl_program *prog)
 792 {
 793    struct prog_instruction *inst;
 794    inst = new_instruction(prog, OPCODE_NOP);
 795    inst->Comment = _mesa_strdup(target);
 796    return inst;
 797 }
 798
 799
 800 static struct prog_instruction *
 801 emit_cjump(const char *target, struct gl_program *prog, GLuint zeroOrOne)
 802 {
 803    struct prog_instruction *inst;
 804    inst = new_instruction(prog, OPCODE_BRA);
 805    if (zeroOrOne)
 806       inst->DstReg.CondMask = COND_NE;  /* branch if non-zero */
 807    else
 808       inst->DstReg.CondMask = COND_EQ;  /* branch if equal to zero */
 809    inst->DstReg.CondSwizzle = SWIZZLE_X;
 810    inst->Comment = _mesa_strdup(target);
 811    return inst;
 812 }
 813
 814
 815 static struct prog_instruction *
 816 emit_jump(const char *target, struct gl_program *prog)
 817 {
 818    struct prog_instruction *inst;
 819    inst = new_instruction(prog, OPCODE_BRA);
 820    inst->DstReg.CondMask = COND_TR;  /* always branch */
 821    /*inst->DstReg.CondSwizzle = SWIZZLE_X;*/
 822    inst->Comment = _mesa_strdup(target);
 823    return inst;
 824 }
 825
 826
 827 static struct prog_instruction *
 828 emit_kill(struct gl_program *prog)
 829 {
 830    struct prog_instruction *inst;
 831    /* NV-KILL - discard fragment depending on condition code.
 832     * Note that ARB-KILL depends on sign of vector operand.
 833     */
 834    inst = new_instruction(prog, OPCODE_KIL_NV);
 835    inst->DstReg.CondMask = COND_TR;  /* always branch */
 836    return inst;
 837 }
 838
 839
 840 static struct prog_instruction *
 841 emit_tex(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 842 {
 843    struct prog_instruction *inst;
 844    if (n->Opcode == IR_TEX) {
 845       inst = new_instruction(prog, OPCODE_TEX);
 846    }
 847    else if (n->Opcode == IR_TEXB) {
 848       inst = new_instruction(prog, OPCODE_TXB);
 849    }
 850    else {
 851       assert(n->Opcode == IR_TEXP);
 852       inst = new_instruction(prog, OPCODE_TXP);
 853    }
 854
 855    if (!n->Store)
 856       if (!alloc_temp_storage(vt, n, 4))
 857          return NULL;
 858
 859    storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 860
 861    /* Child[1] is the coord */
 862    storage_to_src_reg(&inst->SrcReg[0], n->Children[1]->Store);
 863
 864    /* Child[0] is the sampler (a uniform which'll indicate the texture unit) */
 865    assert(n->Children[0]->Store);
 866    assert(n->Children[0]->Store->Size >= TEXTURE_1D_INDEX);
 867
 868    inst->Sampler = n->Children[0]->Store->Index; /* i.e. uniform's index */
 869    inst->TexSrcTarget = n->Children[0]->Store->Size;
 870    inst->TexSrcUnit = 27; /* Dummy value; the TexSrcUnit will be computed at
 871                            * link time, using the sampler uniform's value.
 872                            */
 873    return inst;
 874 }
 875
 876
 877 static struct prog_instruction *
 878 emit_move(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 879 {
 880    struct prog_instruction *inst;
 881
 882    /* rhs */
 883    assert(n->Children[1]);
 884    inst = emit(vt, n->Children[1], prog);
 885
 886    assert(n->Children[1]->Store->Index >= 0);
 887
 888    /* lhs */
 889    emit(vt, n->Children[0], prog);
 890
 891    assert(!n->Store);
 892    n->Store = n->Children[0]->Store;
 893
 894 #if PEEPHOLE_OPTIMIZATIONS
 895    if (inst && _slang_is_temp(vt, n->Children[1]->Store)) {
 896       /* Peephole optimization:
 897        * Just modify the RHS to put its result into the dest of this
 898        * MOVE operation.  Then, this MOVE is a no-op.
 899        */
 900       _slang_free_temp(vt, n->Children[1]->Store);
 901       *n->Children[1]->Store = *n->Children[0]->Store;
 902       /* fixup the prev (RHS) instruction */
 903       assert(n->Children[0]->Store->Index >= 0);
 904       assert(n->Children[0]->Store->Index < 16);
 905       storage_to_dst_reg(&inst->DstReg, n->Children[0]->Store, n->Writemask);
 906       return inst;
 907    }
 908    else
 909 #endif
 910    {
 911       if (n->Children[0]->Store->Size > 4) {
 912          /* move matrix/struct etc (block of registers) */
 913          slang_ir_storage dstStore = *n->Children[0]->Store;
 914          slang_ir_storage srcStore = *n->Children[1]->Store;
 915          GLint size = srcStore.Size;
 916          ASSERT(n->Children[0]->Writemask == WRITEMASK_XYZW);
 917          ASSERT(n->Children[1]->Store->Swizzle == SWIZZLE_NOOP);
 918          dstStore.Size = 4;
 919          srcStore.Size = 4;
 920          while (size >= 4) {
 921             inst = new_instruction(prog, OPCODE_MOV);
 922             inst->Comment = _mesa_strdup("IR_MOVE block");
 923             storage_to_dst_reg(&inst->DstReg, &dstStore, n->Writemask);
 924             storage_to_src_reg(&inst->SrcReg[0], &srcStore);
 925             srcStore.Index++;
 926             dstStore.Index++;
 927             size -= 4;
 928          }
 929       }
 930       else {
 931          /* single register move */
 932          char *srcAnnot, *dstAnnot;
 933          inst = new_instruction(prog, OPCODE_MOV);
 934          assert(n->Children[0]->Store->Index >= 0);
 935          assert(n->Children[0]->Store->Index < 16);
 936          storage_to_dst_reg(&inst->DstReg, n->Children[0]->Store, n->Writemask);
 937          storage_to_src_reg(&inst->SrcReg[0], n->Children[1]->Store);
 938          dstAnnot = storage_annotation(n->Children[0], prog);
 939          srcAnnot = storage_annotation(n->Children[1], prog);
 940          inst->Comment = instruction_annotation(inst->Opcode, dstAnnot,
 941                                                 srcAnnot, NULL, NULL);
 942       }
 943       free_temp_storage(vt, n->Children[1]);
 944       return inst;
 945    }
 946 }
 947
 948
 949 static struct prog_instruction *
 950 emit_cond(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
 951 {
 952    /* Conditional expression (in if/while/for stmts).
 953     * Need to update condition code register.
 954     * Next instruction is typically an IR_CJUMP0/1.
 955     */
 956    /* last child expr instruction: */
 957    struct prog_instruction *inst = emit(vt, n->Children[0], prog);
 958    if (inst) {
 959       /* set inst's CondUpdate flag */
 960       inst->CondUpdate = GL_TRUE;
 961       return inst; /* XXX or null? */
 962    }
 963    else {
 964       /* This'll happen for things like "if (i) ..." where no code
 965        * is normally generated for the expression "i".
 966        * Generate a move instruction just to set condition codes.
 967        * Note: must use full 4-component vector since all four
 968        * condition codes must be set identically.
 969        */
 970       if (!alloc_temp_storage(vt, n, 4))
 971          return NULL;
 972       inst = new_instruction(prog, OPCODE_MOV);
 973       inst->CondUpdate = GL_TRUE;
 974       storage_to_dst_reg(&inst->DstReg, n->Store, n->Writemask);
 975       storage_to_src_reg(&inst->SrcReg[0], n->Children[0]->Store);
 976       _slang_free_temp(vt, n->Store);
 977       inst->Comment = _mesa_strdup("COND expr");
 978       return inst; /* XXX or null? */
 979    }
 980 }
 981
 982
 983 /**
 984  * Remove any SWIZZLE_NIL terms from given swizzle mask (smear prev term).
 985  * Ex: fix_swizzle("zyNN") -> "zyyy"
 986  */
 987 static GLuint
 988 fix_swizzle(GLuint swizzle)
 989 {
 990    GLuint swz[4], i;
 991    for (i = 0; i < 4; i++) {
 992       swz[i] = GET_SWZ(swizzle, i);
 993       if (swz[i] == SWIZZLE_NIL) {
 994          swz[i] = swz[i - 1];
 995       }
 996    }
 997    return MAKE_SWIZZLE4(swz[0], swz[1], swz[2], swz[3]);
 998 }
 999
1000
1001 static struct prog_instruction *
1002 emit_swizzle(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
1003 {
1004    GLuint swizzle;
1005
1006    /* swizzled storage access */
1007    (void) emit(vt, n->Children[0], prog);
1008
1009    /* "pull-up" the child's storage info, applying our swizzle info */
1010    n->Store->File  = n->Children[0]->Store->File;
1011    n->Store->Index = n->Children[0]->Store->Index;
1012    n->Store->Size  = n->Children[0]->Store->Size;
1013    /*n->Var = n->Children[0]->Var; XXX for debug */
1014    assert(n->Store->Index >= 0);
1015
1016    swizzle = fix_swizzle(n->Store->Swizzle);
1017 #ifdef DEBUG
1018    {
1019       GLuint s = n->Children[0]->Store->Swizzle;
1020       assert(GET_SWZ(s, 0) != SWIZZLE_NIL);
1021       assert(GET_SWZ(s, 1) != SWIZZLE_NIL);
1022       assert(GET_SWZ(s, 2) != SWIZZLE_NIL);
1023       assert(GET_SWZ(s, 3) != SWIZZLE_NIL);
1024    }
1025 #endif
1026
1027    /* apply this swizzle to child's swizzle to get composed swizzle */
1028    n->Store->Swizzle = swizzle_swizzle(n->Children[0]->Store->Swizzle,
1029                                        swizzle);
1030    return NULL;
1031 }
1032
1033
1034 static struct prog_instruction *
1035 emit(slang_var_table *vt, slang_ir_node *n, struct gl_program *prog)
1036 {
1037    struct prog_instruction *inst;
1038    if (!n)
1039       return NULL;
1040
1041    switch (n->Opcode) {
1042    case IR_SEQ:
1043       /* sequence of two sub-trees */
1044       assert(n->Children[0]);
1045       assert(n->Children[1]);
1046       emit(vt, n->Children[0], prog);
1047       inst = emit(vt, n->Children[1], prog);
1048       assert(!n->Store);
1049       n->Store = n->Children[1]->Store;
1050       return inst;
1051
1052    case IR_SCOPE:
1053       /* new variable scope */
1054       _slang_push_var_table(vt);
1055       inst = emit(vt, n->Children[0], prog);
1056       _slang_pop_var_table(vt);
1057       return inst;
1058
1059    case IR_VAR_DECL:
1060       /* Variable declaration - allocate a register for it */
1061       assert(n->Store);
1062       assert(n->Store->File != PROGRAM_UNDEFINED);
1063       assert(n->Store->Size > 0);
1064       assert(n->Store->Index < 0);
1065       if (!n->Var || n->Var->isTemp) {
1066          /* a nameless/temporary variable, will be freed after first use */
1067          if (!_slang_alloc_temp(vt, n->Store))
1068             RETURN_ERROR("Ran out of registers, too many temporaries", 0);
1069       }
1070       else {
1071          /* a regular variable */
1072          _slang_add_variable(vt, n->Var);
1073          if (!_slang_alloc_var(vt, n->Store))
1074             RETURN_ERROR("Ran out of registers, too many variables", 0);
1075          /*
1076          printf("IR_VAR_DECL %s %d store %p\n",
1077                 (char*) n->Var->a_name, n->Store->Index, (void*) n->Store);
1078          */
1079          assert(n->Var->aux == n->Store);
1080       }
1081       break;
1082
1083    case IR_VAR:
1084       /* Reference to a variable
1085        * Storage should have already been resolved/allocated.
1086        */
1087       assert(n->Store);
1088       assert(n->Store->File != PROGRAM_UNDEFINED);
1089       if (n->Store->Index < 0) {
1090          printf("#### VAR %s not allocated!\n", (char*)n->Var->a_name);
1091       }
1092       assert(n->Store->Index >= 0);
1093       assert(n->Store->Size > 0);
1094       break;
1095
1096    case IR_ELEMENT:
1097       /* Dereference array element.  Just resolve storage for the array
1098        * element represented by this node.
1099        */
1100       assert(n->Store);
1101       assert(n->Store->File != PROGRAM_UNDEFINED);
1102       assert(n->Store->Size > 0);
1103       if (n->Children[1]->Opcode == IR_FLOAT) {
1104          /* OK, constant index */
1105          const GLint arrayAddr = n->Children[0]->Store->Index;
1106          const GLint index = (GLint) n->Children[1]->Value[0];
1107          n->Store->Index = arrayAddr + index;
1108       }
1109       else {
1110          /* Problem: variable index */
1111          const GLint arrayAddr = n->Children[0]->Store->Index;
1112          const GLint index = 0;
1113          _mesa_problem(NULL, "variable array indexes not supported yet!");
1114          n->Store->Index = arrayAddr + index;
1115       }
1116       return NULL; /* no instruction */
1117
1118    case IR_SWIZZLE:
1119       return emit_swizzle(vt, n, prog);
1120
1121    /* Simple arithmetic */
1122    /* unary */
1123    case IR_RSQ:
1124    case IR_RCP:
1125    case IR_FLOOR:
1126    case IR_FRAC:
1127    case IR_F_TO_I:
1128    case IR_ABS:
1129    case IR_SIN:
1130    case IR_COS:
1131    case IR_DDX:
1132    case IR_DDY:
1133    case IR_NOISE1:
1134    case IR_NOISE2:
1135    case IR_NOISE3:
1136    case IR_NOISE4:
1137    /* binary */
1138    case IR_ADD:
1139    case IR_SUB:
1140    case IR_MUL:
1141    case IR_DOT4:
1142    case IR_DOT3:
1143    case IR_CROSS:
1144    case IR_MIN:
1145    case IR_MAX:
1146    case IR_SEQUAL:
1147    case IR_SNEQUAL:
1148    case IR_SGE:
1149    case IR_SGT:
1150    case IR_POW:
1151    case IR_EXP:
1152    case IR_EXP2:
1153    /* trinary operators */
1154    case IR_LRP:
1155       return emit_arith(vt, n, prog);
1156    case IR_CLAMP:
1157       return emit_clamp(vt, n, prog);
1158    case IR_TEX:
1159    case IR_TEXB:
1160    case IR_TEXP:
1161       return emit_tex(vt, n, prog);
1162    case IR_NEG:
1163       return emit_negation(vt, n, prog);
1164    case IR_FLOAT:
1165       /* find storage location for this float constant */
1166       n->Store->Index = _mesa_add_unnamed_constant(prog->Parameters, n->Value,
1167                                                    n->Store->Size,
1168                                                    &n->Store->Swizzle);
1169       if (n->Store->Index < 0) {
1170          RETURN_ERROR("Ran out of space for constants.", 0);
1171       }
1172       return NULL;
1173
1174    case IR_MOVE:
1175       return emit_move(vt, n, prog);
1176
1177    case IR_COND:
1178       return emit_cond(vt, n, prog);
1179
1180    case IR_LABEL:
1181       return emit_label(n->Target, prog);
1182    case IR_JUMP:
1183       return emit_jump(n->Target, prog);
1184    case IR_CJUMP0:
1185       return emit_cjump(n->Target, prog, 0);
1186    case IR_CJUMP1:
1187       return emit_cjump(n->Target, prog, 1);
1188    case IR_KILL:
1189       return emit_kill(prog);
1190
1191    case IR_IF:
1192       {
1193          struct prog_instruction *inst;
1194          emit(vt, n->Children[0], prog);  /* the condition */
1195          inst = new_instruction(prog, OPCODE_IF);
1196          inst->DstReg.CondMask = COND_NE;  /* if cond is non-zero */
1197          inst->DstReg.CondSwizzle = SWIZZLE_X;
1198          return inst;
1199       }
1200    case IR_ELSE:
1201       {
1202          struct prog_instruction *inst;
1203          inst = new_instruction(prog, OPCODE_ELSE);
1204          return inst;
1205       }
1206    case IR_ENDIF:
1207       {
1208          struct prog_instruction *inst;
1209          inst = new_instruction(prog, OPCODE_ENDIF);
1210          return inst;
1211       }
1212
1213    default:
1214       _mesa_problem(NULL, "Unexpected IR opcode in emit()\n");
1215       abort();
1216    }
1217    return NULL;
1218 }
1219
1220
1221 GLboolean
1222 _slang_emit_code(slang_ir_node *n, slang_var_table *vt,
1223                  struct gl_program *prog, GLboolean withEnd)
1224 {
1225    GLboolean success;
1226
1227    if (emit(vt, n, prog)) {
1228       /* finish up by adding the END opcode to program */
1229       if (withEnd) {
1230          struct prog_instruction *inst;
1231          inst = new_instruction(prog, OPCODE_END);
1232       }
1233       success = GL_TRUE;
1234    }
1235    else {
1236       /* record an error? */
1237       success = GL_FALSE;
1238    }
1239
1240    printf("*********** End generate code (%u inst):\n", prog->NumInstructions);
1241 #if 0
1242    _mesa_print_program(prog);
1243    _mesa_print_program_parameters(ctx,prog);
1244 #endif
1245
1246    return success;
1247 }