src/gallium/auxiliary/gallivm/lp_bld_intr.c

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  27
  28
  29 /**
  30  * @file
  31  * Helpers for emiting intrinsic calls.
  32  *
  33  * LLVM vanilla IR doesn't represent all basic arithmetic operations we care
  34  * about, and it is often necessary to resort target-specific intrinsics for
  35  * performance, convenience.
  36  *
  37  * Ideally we would like to stay away from target specific intrinsics and
  38  * move all the instruction selection logic into upstream LLVM where it belongs.
  39  *
  40  * These functions are also used for calling C functions provided by us from
  41  * generated LLVM code.
  42  *
  43  * @author Jose Fonseca <jfonseca@vmware.com>
  44  */
  45
  46
  47 #include "util/u_debug.h"
  48 #include "util/u_string.h"
  49 #include "util/bitscan.h"
  50
  51 #include "lp_bld_const.h"
  52 #include "lp_bld_intr.h"
  53 #include "lp_bld_type.h"
  54 #include "lp_bld_pack.h"
  55 #include "lp_bld_debug.h"
  56
  57
  58 void
  59 lp_format_intrinsic(char *name,
  60                     size_t size,
  61                     const char *name_root,
  62                     LLVMTypeRef type)
  63 {
  64    unsigned length = 0;
  65    unsigned width;
  66    char c;
  67
  68    LLVMTypeKind kind = LLVMGetTypeKind(type);
  69    if (kind == LLVMVectorTypeKind) {
  70       length = LLVMGetVectorSize(type);
  71       type = LLVMGetElementType(type);
  72       kind = LLVMGetTypeKind(type);
  73    }
  74
  75    switch (kind) {
  76    case LLVMIntegerTypeKind:
  77       c = 'i';
  78       width = LLVMGetIntTypeWidth(type);
  79       break;
  80    case LLVMFloatTypeKind:
  81       c = 'f';
  82       width = 32;
  83       break;
  84    case LLVMDoubleTypeKind:
  85       c = 'f';
  86       width = 64;
  87       break;
  88    default:
  89       unreachable("unexpected LLVMTypeKind");
  90    }
  91
  92    if (length) {
  93       util_snprintf(name, size, "%s.v%u%c%u", name_root, length, c, width);
  94    } else {
  95       util_snprintf(name, size, "%s.%c%u", name_root, c, width);
  96    }
  97 }
  98
  99
 100 LLVMValueRef
 101 lp_declare_intrinsic(LLVMModuleRef module,
 102                      const char *name,
 103                      LLVMTypeRef ret_type,
 104                      LLVMTypeRef *arg_types,
 105                      unsigned num_args)
 106 {
 107    LLVMTypeRef function_type;
 108    LLVMValueRef function;
 109
 110    assert(!LLVMGetNamedFunction(module, name));
 111
 112    function_type = LLVMFunctionType(ret_type, arg_types, num_args, 0);
 113    function = LLVMAddFunction(module, name, function_type);
 114
 115    LLVMSetFunctionCallConv(function, LLVMCCallConv);
 116    LLVMSetLinkage(function, LLVMExternalLinkage);
 117
 118    assert(LLVMIsDeclaration(function));
 119
 120    return function;
 121 }
 122
 123
 124 #if HAVE_LLVM < 0x0400
 125 static LLVMAttribute lp_attr_to_llvm_attr(enum lp_func_attr attr)
 126 {
 127    switch (attr) {
 128    case LP_FUNC_ATTR_ALWAYSINLINE: return LLVMAlwaysInlineAttribute;
 129    case LP_FUNC_ATTR_BYVAL: return LLVMByValAttribute;
 130    case LP_FUNC_ATTR_INREG: return LLVMInRegAttribute;
 131    case LP_FUNC_ATTR_NOALIAS: return LLVMNoAliasAttribute;
 132    case LP_FUNC_ATTR_NOUNWIND: return LLVMNoUnwindAttribute;
 133    case LP_FUNC_ATTR_READNONE: return LLVMReadNoneAttribute;
 134    case LP_FUNC_ATTR_READONLY: return LLVMReadOnlyAttribute;
 135    default:
 136       _debug_printf("Unhandled function attribute: %x\n", attr);
 137       return 0;
 138    }
 139 }
 140
 141 #else
 142
 143 static const char *attr_to_str(enum lp_func_attr attr)
 144 {
 145    switch (attr) {
 146    case LP_FUNC_ATTR_ALWAYSINLINE: return "alwaysinline";
 147    case LP_FUNC_ATTR_BYVAL: return "byval";
 148    case LP_FUNC_ATTR_INREG: return "inreg";
 149    case LP_FUNC_ATTR_NOALIAS: return "noalias";
 150    case LP_FUNC_ATTR_NOUNWIND: return "nounwind";
 151    case LP_FUNC_ATTR_READNONE: return "readnone";
 152    case LP_FUNC_ATTR_READONLY: return "readonly";
 153    case LP_FUNC_ATTR_WRITEONLY: return "writeonly";
 154    case LP_FUNC_ATTR_INACCESSIBLE_MEM_ONLY: return "inaccessiblememonly";
 155    case LP_FUNC_ATTR_CONVERGENT: return "convergent";
 156    default:
 157       _debug_printf("Unhandled function attribute: %x\n", attr);
 158       return 0;
 159    }
 160 }
 161
 162 #endif
 163
 164 void
 165 lp_add_function_attr(LLVMValueRef function_or_call,
 166                      int attr_idx, enum lp_func_attr attr)
 167 {
 168
 169 #if HAVE_LLVM < 0x0400
 170    LLVMAttribute llvm_attr = lp_attr_to_llvm_attr(attr);
 171    if (LLVMIsAFunction(function_or_call)) {
 172       if (attr_idx == -1) {
 173          LLVMAddFunctionAttr(function_or_call, llvm_attr);
 174       } else {
 175          LLVMAddAttribute(LLVMGetParam(function_or_call, attr_idx - 1), llvm_attr);
 176       }
 177    } else {
 178       LLVMAddInstrAttribute(function_or_call, attr_idx, llvm_attr);
 179    }
 180 #else
 181
 182    LLVMModuleRef module;
 183    if (LLVMIsAFunction(function_or_call)) {
 184       module = LLVMGetGlobalParent(function_or_call);
 185    } else {
 186       LLVMBasicBlockRef bb = LLVMGetInstructionParent(function_or_call);
 187       LLVMValueRef function = LLVMGetBasicBlockParent(bb);
 188       module = LLVMGetGlobalParent(function);
 189    }
 190    LLVMContextRef ctx = LLVMGetModuleContext(module);
 191
 192    const char *attr_name = attr_to_str(attr);
 193    unsigned kind_id = LLVMGetEnumAttributeKindForName(attr_name,
 194                                                       strlen(attr_name));
 195    LLVMAttributeRef llvm_attr = LLVMCreateEnumAttribute(ctx, kind_id, 0);
 196
 197    if (LLVMIsAFunction(function_or_call))
 198       LLVMAddAttributeAtIndex(function_or_call, attr_idx, llvm_attr);
 199    else
 200       LLVMAddCallSiteAttribute(function_or_call, attr_idx, llvm_attr);
 201 #endif
 202 }
 203
 204 static void
 205 lp_add_func_attributes(LLVMValueRef function, unsigned attrib_mask)
 206 {
 207    /* NoUnwind indicates that the intrinsic never raises a C++ exception.
 208     * Set it for all intrinsics.
 209     */
 210    attrib_mask |= LP_FUNC_ATTR_NOUNWIND;
 211    attrib_mask &= ~LP_FUNC_ATTR_LEGACY;
 212
 213    while (attrib_mask) {
 214       enum lp_func_attr attr = 1u << u_bit_scan(&attrib_mask);
 215       lp_add_function_attr(function, -1, attr);
 216    }
 217 }
 218
 219 LLVMValueRef
 220 lp_build_intrinsic(LLVMBuilderRef builder,
 221                    const char *name,
 222                    LLVMTypeRef ret_type,
 223                    LLVMValueRef *args,
 224                    unsigned num_args,
 225                    unsigned attr_mask)
 226 {
 227    LLVMModuleRef module = LLVMGetGlobalParent(LLVMGetBasicBlockParent(LLVMGetInsertBlock(builder)));
 228    LLVMValueRef function, call;
 229    bool set_callsite_attrs = HAVE_LLVM >= 0x0400 &&
 230                              !(attr_mask & LP_FUNC_ATTR_LEGACY);
 231
 232    function = LLVMGetNamedFunction(module, name);
 233    if(!function) {
 234       LLVMTypeRef arg_types[LP_MAX_FUNC_ARGS];
 235       unsigned i;
 236
 237       assert(num_args <= LP_MAX_FUNC_ARGS);
 238
 239       for(i = 0; i < num_args; ++i) {
 240          assert(args[i]);
 241          arg_types[i] = LLVMTypeOf(args[i]);
 242       }
 243
 244       function = lp_declare_intrinsic(module, name, ret_type, arg_types, num_args);
 245
 246       if (!set_callsite_attrs)
 247          lp_add_func_attributes(function, attr_mask);
 248
 249       if (gallivm_debug & GALLIVM_DEBUG_IR) {
 250          lp_debug_dump_value(function);
 251       }
 252    }
 253
 254    call = LLVMBuildCall(builder, function, args, num_args, "");
 255    if (set_callsite_attrs)
 256       lp_add_func_attributes(call, attr_mask);
 257    return call;
 258 }
 259
 260
 261 LLVMValueRef
 262 lp_build_intrinsic_unary(LLVMBuilderRef builder,
 263                          const char *name,
 264                          LLVMTypeRef ret_type,
 265                          LLVMValueRef a)
 266 {
 267    return lp_build_intrinsic(builder, name, ret_type, &a, 1, 0);
 268 }
 269
 270
 271 LLVMValueRef
 272 lp_build_intrinsic_binary(LLVMBuilderRef builder,
 273                           const char *name,
 274                           LLVMTypeRef ret_type,
 275                           LLVMValueRef a,
 276                           LLVMValueRef b)
 277 {
 278    LLVMValueRef args[2];
 279
 280    args[0] = a;
 281    args[1] = b;
 282
 283    return lp_build_intrinsic(builder, name, ret_type, args, 2, 0);
 284 }
 285
 286
 287 /**
 288  * Call intrinsic with arguments adapted to intrinsic vector length.
 289  *
 290  * Split vectors which are too large for the hw, or expand them if they
 291  * are too small, so a caller calling a function which might use intrinsics
 292  * doesn't need to do splitting/expansion on its own.
 293  * This only supports intrinsics where src and dst types match.
 294  */
 295 LLVMValueRef
 296 lp_build_intrinsic_binary_anylength(struct gallivm_state *gallivm,
 297                                     const char *name,
 298                                     struct lp_type src_type,
 299                                     unsigned intr_size,
 300                                     LLVMValueRef a,
 301                                     LLVMValueRef b)
 302 {
 303    unsigned i;
 304    struct lp_type intrin_type = src_type;
 305    LLVMBuilderRef builder = gallivm->builder;
 306    LLVMValueRef i32undef = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
 307    LLVMValueRef anative, bnative;
 308    unsigned intrin_length = intr_size / src_type.width;
 309
 310    intrin_type.length = intrin_length;
 311
 312    if (intrin_length > src_type.length) {
 313       LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 314       LLVMValueRef constvec, tmp;
 315
 316       for (i = 0; i < src_type.length; i++) {
 317          elems[i] = lp_build_const_int32(gallivm, i);
 318       }
 319       for (; i < intrin_length; i++) {
 320          elems[i] = i32undef;
 321       }
 322       if (src_type.length == 1) {
 323          LLVMTypeRef elem_type = lp_build_elem_type(gallivm, intrin_type);
 324          a = LLVMBuildBitCast(builder, a, LLVMVectorType(elem_type, 1), "");
 325          b = LLVMBuildBitCast(builder, b, LLVMVectorType(elem_type, 1), "");
 326       }
 327       constvec = LLVMConstVector(elems, intrin_length);
 328       anative = LLVMBuildShuffleVector(builder, a, a, constvec, "");
 329       bnative = LLVMBuildShuffleVector(builder, b, b, constvec, "");
 330       tmp = lp_build_intrinsic_binary(builder, name,
 331                                       lp_build_vec_type(gallivm, intrin_type),
 332                                       anative, bnative);
 333       if (src_type.length > 1) {
 334          constvec = LLVMConstVector(elems, src_type.length);
 335          return LLVMBuildShuffleVector(builder, tmp, tmp, constvec, "");
 336       }
 337       else {
 338          return LLVMBuildExtractElement(builder, tmp, elems[0], "");
 339       }
 340    }
 341    else if (intrin_length < src_type.length) {
 342       unsigned num_vec = src_type.length / intrin_length;
 343       LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH];
 344
 345       /* don't support arbitrary size here as this is so yuck */
 346       if (src_type.length % intrin_length) {
 347          /* FIXME: This is something which should be supported
 348           * but there doesn't seem to be any need for it currently
 349           * so crash and burn.
 350           */
 351          debug_printf("%s: should handle arbitrary vector size\n",
 352                       __FUNCTION__);
 353          assert(0);
 354          return NULL;
 355       }
 356
 357       for (i = 0; i < num_vec; i++) {
 358          anative = lp_build_extract_range(gallivm, a, i*intrin_length,
 359                                         intrin_length);
 360          bnative = lp_build_extract_range(gallivm, b, i*intrin_length,
 361                                         intrin_length);
 362          tmp[i] = lp_build_intrinsic_binary(builder, name,
 363                                             lp_build_vec_type(gallivm, intrin_type),
 364                                             anative, bnative);
 365       }
 366       return lp_build_concat(gallivm, tmp, intrin_type, num_vec);
 367    }
 368    else {
 369       return lp_build_intrinsic_binary(builder, name,
 370                                        lp_build_vec_type(gallivm, src_type),
 371                                        a, b);
 372    }
 373 }
 374
 375
 376 LLVMValueRef
 377 lp_build_intrinsic_map(struct gallivm_state *gallivm,
 378                        const char *name,
 379                        LLVMTypeRef ret_type,
 380                        LLVMValueRef *args,
 381                        unsigned num_args)
 382 {
 383    LLVMBuilderRef builder = gallivm->builder;
 384    LLVMTypeRef ret_elem_type = LLVMGetElementType(ret_type);
 385    unsigned n = LLVMGetVectorSize(ret_type);
 386    unsigned i, j;
 387    LLVMValueRef res;
 388
 389    assert(num_args <= LP_MAX_FUNC_ARGS);
 390
 391    res = LLVMGetUndef(ret_type);
 392    for(i = 0; i < n; ++i) {
 393       LLVMValueRef index = lp_build_const_int32(gallivm, i);
 394       LLVMValueRef arg_elems[LP_MAX_FUNC_ARGS];
 395       LLVMValueRef res_elem;
 396       for(j = 0; j < num_args; ++j)
 397          arg_elems[j] = LLVMBuildExtractElement(builder, args[j], index, "");
 398       res_elem = lp_build_intrinsic(builder, name, ret_elem_type, arg_elems, num_args, 0);
 399       res = LLVMBuildInsertElement(builder, res, res_elem, index, "");
 400    }
 401
 402    return res;
 403 }
 404
 405
 406 LLVMValueRef
 407 lp_build_intrinsic_map_unary(struct gallivm_state *gallivm,
 408                              const char *name,
 409                              LLVMTypeRef ret_type,
 410                              LLVMValueRef a)
 411 {
 412    return lp_build_intrinsic_map(gallivm, name, ret_type, &a, 1);
 413 }
 414
 415
 416 LLVMValueRef
 417 lp_build_intrinsic_map_binary(struct gallivm_state *gallivm,
 418                               const char *name,
 419                               LLVMTypeRef ret_type,
 420                               LLVMValueRef a,
 421                               LLVMValueRef b)
 422 {
 423    LLVMValueRef args[2];
 424
 425    args[0] = a;
 426    args[1] = b;
 427
 428    return lp_build_intrinsic_map(gallivm, name, ret_type, args, 2);
 429 }
 430
 431