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 (attr_idx == -1) {
 172       LLVMAddFunctionAttr(function_or_call, llvm_attr);
 173    } else {
 174       LLVMAddAttribute(LLVMGetParam(function_or_call, attr_idx - 1), llvm_attr);
 175    }
 176 #else
 177
 178    LLVMModuleRef module;
 179    if (LLVMIsAFunction(function_or_call)) {
 180       module = LLVMGetGlobalParent(function_or_call);
 181    } else {
 182       LLVMBasicBlockRef bb = LLVMGetInstructionParent(function_or_call);
 183       LLVMValueRef function = LLVMGetBasicBlockParent(bb);
 184       module = LLVMGetGlobalParent(function);
 185    }
 186    LLVMContextRef ctx = LLVMGetModuleContext(module);
 187
 188    const char *attr_name = attr_to_str(attr);
 189    unsigned kind_id = LLVMGetEnumAttributeKindForName(attr_name,
 190                                                       strlen(attr_name));
 191    LLVMAttributeRef llvm_attr = LLVMCreateEnumAttribute(ctx, kind_id, 0);
 192
 193    if (LLVMIsAFunction(function_or_call))
 194       LLVMAddAttributeAtIndex(function_or_call, attr_idx, llvm_attr);
 195    else
 196       LLVMAddCallSiteAttribute(function_or_call, attr_idx, llvm_attr);
 197 #endif
 198 }
 199
 200 static void
 201 lp_add_func_attributes(LLVMValueRef function, unsigned attrib_mask)
 202 {
 203    /* NoUnwind indicates that the intrinsic never raises a C++ exception.
 204     * Set it for all intrinsics.
 205     */
 206    attrib_mask |= LP_FUNC_ATTR_NOUNWIND;
 207    attrib_mask &= ~LP_FUNC_ATTR_LEGACY;
 208
 209    while (attrib_mask) {
 210       enum lp_func_attr attr = 1u << u_bit_scan(&attrib_mask);
 211       lp_add_function_attr(function, -1, attr);
 212    }
 213 }
 214
 215 LLVMValueRef
 216 lp_build_intrinsic(LLVMBuilderRef builder,
 217                    const char *name,
 218                    LLVMTypeRef ret_type,
 219                    LLVMValueRef *args,
 220                    unsigned num_args,
 221                    unsigned attr_mask)
 222 {
 223    LLVMModuleRef module = LLVMGetGlobalParent(LLVMGetBasicBlockParent(LLVMGetInsertBlock(builder)));
 224    LLVMValueRef function, call;
 225    bool set_callsite_attrs = HAVE_LLVM >= 0x0400 &&
 226                              !(attr_mask & LP_FUNC_ATTR_LEGACY);
 227
 228    function = LLVMGetNamedFunction(module, name);
 229    if(!function) {
 230       LLVMTypeRef arg_types[LP_MAX_FUNC_ARGS];
 231       unsigned i;
 232
 233       assert(num_args <= LP_MAX_FUNC_ARGS);
 234
 235       for(i = 0; i < num_args; ++i) {
 236          assert(args[i]);
 237          arg_types[i] = LLVMTypeOf(args[i]);
 238       }
 239
 240       function = lp_declare_intrinsic(module, name, ret_type, arg_types, num_args);
 241
 242       if (!set_callsite_attrs)
 243          lp_add_func_attributes(function, attr_mask);
 244
 245       if (gallivm_debug & GALLIVM_DEBUG_IR) {
 246          lp_debug_dump_value(function);
 247       }
 248    }
 249
 250    call = LLVMBuildCall(builder, function, args, num_args, "");
 251    if (set_callsite_attrs)
 252       lp_add_func_attributes(call, attr_mask);
 253    return call;
 254 }
 255
 256
 257 LLVMValueRef
 258 lp_build_intrinsic_unary(LLVMBuilderRef builder,
 259                          const char *name,
 260                          LLVMTypeRef ret_type,
 261                          LLVMValueRef a)
 262 {
 263    return lp_build_intrinsic(builder, name, ret_type, &a, 1, 0);
 264 }
 265
 266
 267 LLVMValueRef
 268 lp_build_intrinsic_binary(LLVMBuilderRef builder,
 269                           const char *name,
 270                           LLVMTypeRef ret_type,
 271                           LLVMValueRef a,
 272                           LLVMValueRef b)
 273 {
 274    LLVMValueRef args[2];
 275
 276    args[0] = a;
 277    args[1] = b;
 278
 279    return lp_build_intrinsic(builder, name, ret_type, args, 2, 0);
 280 }
 281
 282
 283 /**
 284  * Call intrinsic with arguments adapted to intrinsic vector length.
 285  *
 286  * Split vectors which are too large for the hw, or expand them if they
 287  * are too small, so a caller calling a function which might use intrinsics
 288  * doesn't need to do splitting/expansion on its own.
 289  * This only supports intrinsics where src and dst types match.
 290  */
 291 LLVMValueRef
 292 lp_build_intrinsic_binary_anylength(struct gallivm_state *gallivm,
 293                                     const char *name,
 294                                     struct lp_type src_type,
 295                                     unsigned intr_size,
 296                                     LLVMValueRef a,
 297                                     LLVMValueRef b)
 298 {
 299    unsigned i;
 300    struct lp_type intrin_type = src_type;
 301    LLVMBuilderRef builder = gallivm->builder;
 302    LLVMValueRef i32undef = LLVMGetUndef(LLVMInt32TypeInContext(gallivm->context));
 303    LLVMValueRef anative, bnative;
 304    unsigned intrin_length = intr_size / src_type.width;
 305
 306    intrin_type.length = intrin_length;
 307
 308    if (intrin_length > src_type.length) {
 309       LLVMValueRef elems[LP_MAX_VECTOR_LENGTH];
 310       LLVMValueRef constvec, tmp;
 311
 312       for (i = 0; i < src_type.length; i++) {
 313          elems[i] = lp_build_const_int32(gallivm, i);
 314       }
 315       for (; i < intrin_length; i++) {
 316          elems[i] = i32undef;
 317       }
 318       if (src_type.length == 1) {
 319          LLVMTypeRef elem_type = lp_build_elem_type(gallivm, intrin_type);
 320          a = LLVMBuildBitCast(builder, a, LLVMVectorType(elem_type, 1), "");
 321          b = LLVMBuildBitCast(builder, b, LLVMVectorType(elem_type, 1), "");
 322       }
 323       constvec = LLVMConstVector(elems, intrin_length);
 324       anative = LLVMBuildShuffleVector(builder, a, a, constvec, "");
 325       bnative = LLVMBuildShuffleVector(builder, b, b, constvec, "");
 326       tmp = lp_build_intrinsic_binary(builder, name,
 327                                       lp_build_vec_type(gallivm, intrin_type),
 328                                       anative, bnative);
 329       if (src_type.length > 1) {
 330          constvec = LLVMConstVector(elems, src_type.length);
 331          return LLVMBuildShuffleVector(builder, tmp, tmp, constvec, "");
 332       }
 333       else {
 334          return LLVMBuildExtractElement(builder, tmp, elems[0], "");
 335       }
 336    }
 337    else if (intrin_length < src_type.length) {
 338       unsigned num_vec = src_type.length / intrin_length;
 339       LLVMValueRef tmp[LP_MAX_VECTOR_LENGTH];
 340
 341       /* don't support arbitrary size here as this is so yuck */
 342       if (src_type.length % intrin_length) {
 343          /* FIXME: This is something which should be supported
 344           * but there doesn't seem to be any need for it currently
 345           * so crash and burn.
 346           */
 347          debug_printf("%s: should handle arbitrary vector size\n",
 348                       __FUNCTION__);
 349          assert(0);
 350          return NULL;
 351       }
 352
 353       for (i = 0; i < num_vec; i++) {
 354          anative = lp_build_extract_range(gallivm, a, i*intrin_length,
 355                                         intrin_length);
 356          bnative = lp_build_extract_range(gallivm, b, i*intrin_length,
 357                                         intrin_length);
 358          tmp[i] = lp_build_intrinsic_binary(builder, name,
 359                                             lp_build_vec_type(gallivm, intrin_type),
 360                                             anative, bnative);
 361       }
 362       return lp_build_concat(gallivm, tmp, intrin_type, num_vec);
 363    }
 364    else {
 365       return lp_build_intrinsic_binary(builder, name,
 366                                        lp_build_vec_type(gallivm, src_type),
 367                                        a, b);
 368    }
 369 }
 370
 371
 372 LLVMValueRef
 373 lp_build_intrinsic_map(struct gallivm_state *gallivm,
 374                        const char *name,
 375                        LLVMTypeRef ret_type,
 376                        LLVMValueRef *args,
 377                        unsigned num_args)
 378 {
 379    LLVMBuilderRef builder = gallivm->builder;
 380    LLVMTypeRef ret_elem_type = LLVMGetElementType(ret_type);
 381    unsigned n = LLVMGetVectorSize(ret_type);
 382    unsigned i, j;
 383    LLVMValueRef res;
 384
 385    assert(num_args <= LP_MAX_FUNC_ARGS);
 386
 387    res = LLVMGetUndef(ret_type);
 388    for(i = 0; i < n; ++i) {
 389       LLVMValueRef index = lp_build_const_int32(gallivm, i);
 390       LLVMValueRef arg_elems[LP_MAX_FUNC_ARGS];
 391       LLVMValueRef res_elem;
 392       for(j = 0; j < num_args; ++j)
 393          arg_elems[j] = LLVMBuildExtractElement(builder, args[j], index, "");
 394       res_elem = lp_build_intrinsic(builder, name, ret_elem_type, arg_elems, num_args, 0);
 395       res = LLVMBuildInsertElement(builder, res, res_elem, index, "");
 396    }
 397
 398    return res;
 399 }
 400
 401
 402 LLVMValueRef
 403 lp_build_intrinsic_map_unary(struct gallivm_state *gallivm,
 404                              const char *name,
 405                              LLVMTypeRef ret_type,
 406                              LLVMValueRef a)
 407 {
 408    return lp_build_intrinsic_map(gallivm, name, ret_type, &a, 1);
 409 }
 410
 411
 412 LLVMValueRef
 413 lp_build_intrinsic_map_binary(struct gallivm_state *gallivm,
 414                               const char *name,
 415                               LLVMTypeRef ret_type,
 416                               LLVMValueRef a,
 417                               LLVMValueRef b)
 418 {
 419    LLVMValueRef args[2];
 420
 421    args[0] = a;
 422    args[1] = b;
 423
 424    return lp_build_intrinsic_map(gallivm, name, ret_type, args, 2);
 425 }
 426
 427