codegen_c.cc 25.1 KB
Newer Older
1 2 3 4
/*!
 *  Copyright (c) 2017 by Contributors
 * \file codegen_c.cc
 */
5
#include <iomanip>
6
#include <cctype>
7
#include "./codegen_c.h"
8
#include "../pass/ir_util.h"
9
#include "../arithmetic/compute_expr.h"
10 11 12 13 14 15

namespace tvm {
namespace codegen {

using namespace ir;

16
void CodeGenC::Init(bool output_ssa) {
17
  print_ssa_form_ = output_ssa;
18 19 20 21 22
}

void CodeGenC::InitFuncState(LoweredFunc f) {
  alloc_storage_scope_.clear();
  handle_data_type_.clear();
23
  CodeGenSourceBase::ClearFuncState();
24 25 26 27
}
void CodeGenC::AddFunction(LoweredFunc f) {
  // clear previous generated state.
  this->InitFuncState(f);
28
  // skip the first underscore, so SSA variable starts from _1
29
  GetUniqueName("_");
30
  GetUniqueName("extern");
31 32
  // add to alloc buffer type.
  for (const auto & kv : f->handle_data_type) {
33
    RegisterHandleType(kv.first.get(), kv.second.type());
34
  }
35

36 37 38
  this->stream << "void " << f->name << "(";
  for (size_t i = 0; i < f->args.size(); ++i) {
    Var v = f->args[i];
39 40
    std::string vid = AllocVarID(v.get());
    if (i != 0) stream << ", ";
41
    if (v.type().is_handle()) {
42
      auto it = alloc_storage_scope_.find(v.get());
43
      if (it != alloc_storage_scope_.end())
44
        PrintStorageScope(it->second, stream);
45 46 47 48 49 50
      stream << ' ';

      if (handle_data_type_.count(v.get())) {
        PrintType(handle_data_type_.at(v.get()), stream);
      } else {
        stream << "void";
51
      }
52
      stream << "*";
53

54 55 56
      if (f->is_restricted && restrict_keyword_.length() != 0) {
        stream << ' ' << restrict_keyword_;
      }
57 58 59
    } else {
      PrintType(v.type(), stream);
    }
60 61 62
    stream << ' ' << vid;
  }
  stream << ") {\n";
63
  int func_scope = this->BeginScope();
64
  this->PrintStmt(f->body);
65
  this->EndScope(func_scope);
66
  this->PrintIndent();
67 68 69 70
  this->stream << "}\n\n";
}

std::string CodeGenC::Finish() {
71
  return decl_stream.str() + stream.str();
72 73 74 75 76
}

void CodeGenC::PrintExpr(const Expr& n, std::ostream& os) {  // NOLINT(*)
  if (print_ssa_form_) {
    std::ostringstream temp;
77
    VisitExpr(n, temp);
78 79
    os << SSAGetID(temp.str(), n.type());
  } else {
80
    VisitExpr(n, os);
81 82 83
  }
}

84 85 86 87 88 89 90
void CodeGenC::PrintSSAAssign(
    const std::string& target, const std::string& src, Type t) {
  PrintType(t, stream);
  stream << ' ' << target << " = ";
  if (src.length() > 3 &&
      src[0] == '(' && src[src.length() - 1] == ')') {
    stream << src.substr(1, src.length() - 2);
91
  } else {
92
    stream << src;
93
  }
94
  stream << ";\n";
95 96 97
}

// Print a reference expression to a buffer.
98
std::string CodeGenC::GetBufferRef(
99
    Type t, const Variable* buffer, Expr index) {
100
  std::ostringstream os;
101
  std::string vid = GetVarID(buffer);
102 103 104 105
  std::string scope;
  if (alloc_storage_scope_.count(buffer)) {
    scope = alloc_storage_scope_.at(buffer);
  }
106
  bool is_vol = volatile_buf_.count(buffer) != 0;
107
  if (t.lanes() == 1) {
108
    if (!HandleTypeMatch(buffer, t) || is_vol) {
109
      os << "((";
110 111 112 113 114 115 116
      if (is_vol) {
        os << "volatile ";
      }
      if (scope.length() != 0) {
        PrintStorageScope(scope, os);
      }
      os << ' ';
117 118 119 120 121 122 123 124 125 126 127
      PrintType(t, os);
      os << "*)" << vid << ')';
    } else {
      os << vid;
    }
    os << '[';
    PrintExpr(index, os);
    os << ']';
  } else {
    // Buffer declared as vector type.
    // optimize for case where it is in register,
128
    if (HandleTypeMatch(buffer, t) && !is_vol) {
129 130 131 132 133 134
      // optimize for constant access
      int offset;
      if (arith::GetConstInt(index, &offset)) {
        CHECK_EQ(offset % t.lanes(), 0)
            << "Find unaligned vector load to a vector type";
        os << vid << '[' << (offset / t.lanes()) << ']';
135
        return os.str();
136 137 138
      }
    }
    os << "((";
139 140 141 142 143 144 145
    if (is_vol) {
      os << "volatile ";
    }
    if (scope.length() != 0) {
      PrintStorageScope(scope, os);
    }
    os << ' ';
146 147 148 149
    PrintType(t, os);
    os << "*)(";
    if (!HandleTypeMatch(buffer, t.element_of())) {
      os << '(';
150 151 152 153
      if (scope.length() != 0) {
        PrintStorageScope(scope, os);
      }
      os << ' ';
154 155 156 157 158 159 160
      PrintType(t.element_of(), os);
      os << "*)";
    }
    os << vid << " + ";
    PrintExpr(index, os);
    os << "))[0]";
  }
161
  return os.str();
162 163
}

164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
// Print a reference expression to a buffer.
std::string CodeGenC::GetStructRef(
    Type t, const Expr& buffer, const Expr& index, int kind) {
  if (kind < intrinsic::kArrKindBound_) {
    std::ostringstream os;
    os << "(((TVMArray*)";
    this->PrintExpr(buffer, os);
    os << ")";
    if (kind == intrinsic::kArrAddr) {
      os << " + ";
      this->PrintExpr(index, os);
      os << ")";
      return os.str();
    }
    os << '[';
    this->PrintExpr(index, os);
    os << "].";
    // other case: get fields.
    switch (kind) {
      case intrinsic::kArrData: os << "data"; break;
      case intrinsic::kArrShape: os << "shape"; break;
      case intrinsic::kArrStrides: os << "strides"; break;
      case intrinsic::kArrNDim: os << "ndim"; break;
      case intrinsic::kArrTypeCode: os << "dtype.code"; break;
      case intrinsic::kArrTypeBits: os << "dtype.bits"; break;
      case intrinsic::kArrTypeLanes: os << "dtype.lanes"; break;
      case intrinsic::kArrDeviceId: os << "ctx.device_id"; break;
      case intrinsic::kArrDeviceType: os << "ctx.device_type"; break;
      default: LOG(FATAL) << "unknown field code";
    }
    os << ')';
    return os.str();
  } else {
    CHECK_LT(kind, intrinsic::kTVMValueKindBound_);
    std::ostringstream os;
    os << "(((TVMValue*)";
    this->PrintExpr(buffer, os);
    os << ")[" << index << "].";
    if (t.is_handle()) {
      os << "v_handle";
    } else if (t.is_float()) {
      os << "v_float64";
    } else if (t.is_int()) {
      os << "v_int64";
    } else {
      LOG(FATAL) << "donot know how to handle type" << t;
    }
    os << ")";
    return os.str();
  }
}

216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232

bool CodeGenC::HandleTypeMatch(const Variable* buf_var, Type t) const {
  auto it = handle_data_type_.find(buf_var);
  if (it == handle_data_type_.end()) return false;
  return it->second == t;
}

void CodeGenC::RegisterHandleType(const Variable* buf_var, Type t) {
  auto it = handle_data_type_.find(buf_var);
  if (it == handle_data_type_.end()) {
    handle_data_type_[buf_var] = t;
  } else {
    CHECK(it->second == t)
        << "conflicting buf var type";
  }
}

233 234 235
void CodeGenC::PrintVecElemLoad(const std::string& vec,
                                Type t, int i,
                                std::ostream& os) {  // NOLINT(*)
236
  os << vec << ".s" << std::hex << i << std::dec;
237 238 239 240 241 242 243
}

void CodeGenC::PrintVecElemStore(const std::string& vec,
                                 Type t, int i,
                                 const std::string& value) {
  this->PrintIndent();
  stream << vec << ".s" << std::hex << i
244
         << " = " << value << ";\n" << std::dec;
245 246
}

247 248 249
std::string CodeGenC::GetVecLoad(
    Type t, const Variable* buffer, Expr base) {
  return GetBufferRef(t, buffer, base);
250 251 252 253 254
}

void CodeGenC::PrintVecStore(const Variable* buffer,
                             Type t, Expr base,
                             const std::string& value) {
255
  std::string ref = GetBufferRef(t, buffer, base);
256
  this->PrintIndent();
257
  stream << ref << " = " << value << ";\n";
258 259
}

260 261 262 263 264 265 266 267 268
std::string CodeGenC::CastFromTo(std::string value, Type from, Type target) {
  if (from == target) return value;
  std::ostringstream os;
  os << "((";
  this->PrintType(target, os);
  os << ")" << value << ")";
  return os.str();
}

269
void CodeGenC::BindThreadIndex(const IterVar& iv) {
270
  LOG(FATAL) << "not implemented";
271 272
}

273
void CodeGenC::PrintStorageSync(const Call* op) { // NOLINT(*)
274 275 276 277 278 279
}

void CodeGenC::PrintStorageScope(const std::string& scope, std::ostream& os) { // NOLINT(*)
  CHECK_EQ(scope, "global");
}

280
void CodeGenC::PrintType(Type t, std::ostream& os) {  // NOLINT(*)
281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340
  CHECK_EQ(t.lanes(), 1)
      << "do not yet support vector types";
  if (t.is_handle()) {
    os << "void*"; return;
  }
  if (t.is_float()) {
    if (t.bits() == 32) {
      os << "float"; return;
    }
    if (t.bits() == 64) {
      os << "double"; return;
    }
  } else if (t.is_uint()) {
    switch (t.bits()) {
      case 8: case 16: case 32: case 64: {
        os << "uint" << t.bits() << "_t"; return;
      }
      case 1: os << "int"; return;
    }
  } else if (t.is_int()) {
    switch (t.bits()) {
      case 8: case 16: case 32: case 64: {
        os << "int" << t.bits() << "_t";  return;
      }
    }
  }
  LOG(FATAL) << "Cannot convert type " << t << " to C type";
}


inline void PrintConst(const IntImm* op, std::ostream& os, CodeGenC* p) { // NOLINT(*)
  if (op->type == Int(32)) {
    std::ostringstream temp;
    temp << op->value;
    p->MarkConst(temp.str());
    os << temp.str();
  } else {
    os << "(";
    p->PrintType(op->type, os);
    os << ")" << op->value;
  }
}

inline void PrintConst(const UIntImm* op, std::ostream& os, CodeGenC* p) { // NOLINT(*)
  if (op->type == UInt(32)) {
    std::ostringstream temp;
    temp << op->value << "U";
    p->MarkConst(temp.str());
    os << temp.str();
  } else {
    os << "(";
    p->PrintType(op->type, os);
    os << ")" << op->value;
  }
}

inline void PrintConst(const FloatImm* op, std::ostream& os, CodeGenC* p) { // NOLINT(*)
  switch (op->type.bits()) {
    case 64: case 32: {
      std::ostringstream temp;
341
      temp << std::scientific << op->value;
342 343 344 345 346 347 348 349
      if (op->type.bits() == 32) temp << 'f';
      p->MarkConst(temp.str());
      os << temp.str();
      break;
    }
    case 16: {
      os << '(';
      p->PrintType(op->type, os);
350
      os << ')' << std::scientific <<op->value << 'f';
351 352 353 354 355 356
      break;
    }
    default: LOG(FATAL) << "Bad bit-width for float: " << op->type << "\n";
  }
}

357 358 359 360 361 362 363 364 365 366 367 368
void CodeGenC::VisitExpr_(const IntImm *op, std::ostream& os) {  // NOLINT(*)
  PrintConst(op, os, this);
}
void CodeGenC::VisitExpr_(const UIntImm *op, std::ostream& os) {  // NOLINT(*)
  PrintConst(op, os, this);
}
void CodeGenC::VisitExpr_(const FloatImm *op, std::ostream& os) { // NOLINT(*)
  PrintConst(op, os, this);
}
void CodeGenC::VisitExpr_(const StringImm *op, std::ostream& os) { // NOLINT(*)
  os << "\"" << op->value << "\"";
}
369 370 371 372 373 374

template<typename T>
inline void PrintBinaryExpr(const T* op,
                            const char *opstr,
                            std::ostream& os,  // NOLINT(*)
                            CodeGenC* p) {
375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391
  if (op->type.lanes() == 1) {
    if (isalpha(opstr[0])) {
      os << opstr << '(';
      p->PrintExpr(op->a, os);
      os << ", ";
      p->PrintExpr(op->b, os);
      os << ')';
    } else {
      os << '(';
      p->PrintExpr(op->a, os);
      os << ' ' << opstr << ' ';
      p->PrintExpr(op->b, os);
      os << ')';
    }
  } else {
    p->PrintVecBinaryOp(opstr, op->type, op->a, op->b, os);
  }
392 393
}

394 395 396 397
inline void PrintBinaryIntrinsitc(const Call* op,
                                  const char *opstr,
                                  std::ostream& os,  // NOLINT(*)
                                  CodeGenC* p) {
398 399 400 401 402 403 404 405 406 407
  if (op->type.lanes() == 1) {
    CHECK_EQ(op->args.size(), 2U);
    os << '(';
    p->PrintExpr(op->args[0], os);
    os << opstr;
    p->PrintExpr(op->args[1], os);
    os << ')';
  } else {
    p->PrintVecBinaryOp(opstr, op->type, op->args[0], op->args[1], os);
  }
408
}
409
void CodeGenC::VisitExpr_(const Cast *op, std::ostream& os) {  // NOLINT(*)
410 411 412
  std::stringstream value;
  this->PrintExpr(op->value, value);
  os << CastFromTo(value.str(), op->value.type(), op->type);
413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465
}
void CodeGenC::VisitExpr_(const Variable *op, std::ostream& os) {  // NOLINT(*)
  os << GetVarID(op);
}
void CodeGenC::VisitExpr_(const Add *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "+", os, this);
}
void CodeGenC::VisitExpr_(const Sub *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "-", os, this);
}
void CodeGenC::VisitExpr_(const Mul *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "*", os, this);
}
void CodeGenC::VisitExpr_(const Div *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "/", os, this);
}
void CodeGenC::VisitExpr_(const Mod *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "%", os, this);
}
void CodeGenC::VisitExpr_(const Min *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "min", os, this);
}
void CodeGenC::VisitExpr_(const Max *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "max", os, this);
}
void CodeGenC::VisitExpr_(const EQ *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "==", os, this);
}
void CodeGenC::VisitExpr_(const NE *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "!=", os, this);
}
void CodeGenC::VisitExpr_(const LT *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "<", os, this);
}
void CodeGenC::VisitExpr_(const LE *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "<=", os, this);
}
void CodeGenC::VisitExpr_(const GT *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, ">", os, this);
}
void CodeGenC::VisitExpr_(const GE *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, ">=", os, this);
}
void CodeGenC::VisitExpr_(const And *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "&&", os, this);
}
void CodeGenC::VisitExpr_(const Or *op, std::ostream& os) {  // NOLINT(*)
  PrintBinaryExpr(op, "||", os, this);
}
void CodeGenC::VisitExpr_(const Not *op, std::ostream& os) {  // NOLINT(*)
  os << '!';
  PrintExpr(op->a, os);
}
466

467
void CodeGenC::VisitExpr_(const Call *op, std::ostream& os) {  // NOLINT(*)
468 469 470 471 472 473 474 475 476 477 478
  if (op->call_type == Call::Extern ||
      op->call_type == Call::PureExtern) {
    os << op->name << "(";
    for (size_t i = 0; i < op->args.size(); i++) {
      this->PrintExpr(op->args[i], os);
      if (i < op->args.size() - 1) {
        os << ", ";
      }
    }
    os << ")";
  } else if (op->is_intrinsic(Call::bitwise_and)) {
479
    PrintBinaryIntrinsitc(op, " & ", os, this);
480
  } else if (op->is_intrinsic(Call::bitwise_xor)) {
481
    PrintBinaryIntrinsitc(op, " ^ ", os, this);
482
  } else if (op->is_intrinsic(Call::bitwise_or)) {
483
    PrintBinaryIntrinsitc(op, " | ", os, this);
484 485 486
  } else if (op->is_intrinsic(Call::bitwise_not)) {
    CHECK_EQ(op->args.size(), 1U);
    os << "(~";
487
    this->PrintExpr(op->args[0], os);
488 489
    os << ')';
  } else if (op->is_intrinsic(Call::shift_left)) {
490
    PrintBinaryIntrinsitc(op, " << ", os, this);
491
  } else if (op->is_intrinsic(Call::shift_right)) {
492
    PrintBinaryIntrinsitc(op, " >> ", os, this);
493 494 495 496 497 498 499 500
  } else if (op->is_intrinsic(intrinsic::tvm_if_then_else)) {
    os << "(";
    PrintExpr(op->args[0], os);
    os << " ? ";
    PrintExpr(op->args[1], os);
    os << " : ";
    PrintExpr(op->args[2], os);
    os << ")";
501
  } else if (op->is_intrinsic(intrinsic::tvm_address_of)) {
502 503 504
    const Load *l = op->args[0].as<Load>();
    CHECK(op->args.size() == 1 && l);
    os << "((";
505 506
    this->PrintType(l->type.element_of(), os);
    os << " *)" << this->GetVarID(l->buffer_var.get())
507
       << " + ";
508
    this->PrintExpr(l->index, os);
509
    os << ')';
510
  } else if (op->is_intrinsic(intrinsic::tvm_struct_get)) {
511
    CHECK_EQ(op->args.size(), 3U);
512 513 514
    os << GetStructRef(
        op->type, op->args[0], op->args[1],
        op->args[2].as<IntImm>()->value);
515 516 517
  } else if (op->is_intrinsic(intrinsic::tvm_handle_is_null)) {
    CHECK_EQ(op->args.size(), 1U);
    os << "(";
518
    this->PrintExpr(op->args[0], os);
519 520
    os << " == NULL)";
  } else {
521 522 523 524 525 526
    if (op->call_type == Call::Intrinsic ||
        op->call_type == Call::PureIntrinsic) {
      LOG(FATAL) << "Unresolved intrinsic " << op->name
                 << " with return type " << op->type;
    } else {
      LOG(FATAL) << "Unresolved call type " << op->call_type;
527 528 529 530
    }
  }
}

531
void CodeGenC::PrintVecBinaryOp(
532
    const std::string& op, Type t,
533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548
    Expr lhs, Expr rhs, std::ostream& os) {  // NOLINT(*)
  if (isalpha(op[0])) {
    os << op << "(";
    this->PrintExpr(lhs, os);
    os << ", ";
    this->PrintExpr(rhs, os);
    os << ")";
  } else {
    os <<"(";
    this->PrintExpr(lhs, os);
    os << ' ' << op << ' ';
    this->PrintExpr(rhs, os);
    os << ")";
  }
}

549
void CodeGenC::VisitExpr_(const Load* op, std::ostream& os) {  // NOLINT(*)
550
  int lanes = op->type.lanes();
551
  // delcare type.
552
  if (op->type.lanes() == 1) {
553
    std::string ref = GetBufferRef(op->type, op->buffer_var.get(), op->index);
554
    os << ref;
555
  } else {
556 557
    CHECK(is_one(op->predicate))
        << "predicated load is not supported";
558
    Expr base;
559
    if (GetRamp1Base(op->index, op->type.lanes(), &base)) {
560
      std::string ref = GetVecLoad(op->type, op->buffer_var.get(), base);
561
      os << ref;
562
    } else {
563 564 565 566
      // The assignment below introduces side-effect, and the resulting value cannot
      // be reused across multiple expression, thus a new scope is needed
      int vec_scope = BeginScope();

567 568 569 570 571
      // load seperately.
      std::string svalue = GetUniqueName("_");
      this->PrintIndent();
      this->PrintType(op->type, stream);
      stream << ' ' << svalue << ";\n";
572 573 574 575 576 577 578
      std::string sindex = SSAGetID(PrintExpr(op->index), op->index.type());
      std::string vid = GetVarID(op->buffer_var.get());
      Type elem_type = op->type.element_of();
      for (int i = 0; i < lanes; ++i) {
        std::ostringstream value_temp;
        if (!HandleTypeMatch(op->buffer_var.get(), elem_type)) {
          value_temp << "((";
579 580 581 582 583 584 585
          if (op->buffer_var.get()->type.is_handle()) {
            auto it = alloc_storage_scope_.find(op->buffer_var.get());
            if (it != alloc_storage_scope_.end()) {
              PrintStorageScope(it->second, value_temp);
              value_temp << ' ';
            }
          }
586
          PrintType(elem_type, value_temp);
587 588 589 590 591 592 593 594 595
          value_temp << "*)" << vid << ')';
        } else {
          value_temp << vid;
        }
        value_temp << '[';
        PrintVecElemLoad(sindex, op->index.type(), i, value_temp);
        value_temp << ']';
        PrintVecElemStore(svalue, op->type, i, value_temp.str());
      }
596
      os << svalue;
597
      EndScope(vec_scope);
598 599 600 601
    }
  }
}

602
void CodeGenC::VisitStmt_(const Store* op) {
603 604 605
  Type t = op->value.type();
  if (t.lanes() == 1) {
    std::string value = this->PrintExpr(op->value);
606
    std::string ref  = this->GetBufferRef(t, op->buffer_var.get(), op->index);
607
    this->PrintIndent();
608
    stream << ref << " = " << value << ";\n";
609
  } else {
610 611
    CHECK(is_one(op->predicate))
        << "Predicated store is not supported";
612
    Expr base;
613
    if (GetRamp1Base(op->index, t.lanes(), &base)) {
614 615 616
      std::string value = this->PrintExpr(op->value);
      this->PrintVecStore(op->buffer_var.get(), t, base, value);
    } else {
617 618 619 620
      // The assignment below introduces side-effect, and the resulting value cannot
      // be reused across multiple expression, thus a new scope is needed
      int vec_scope = BeginScope();

621 622 623 624 625 626 627 628 629
      // store elements seperately
      std::string index = SSAGetID(PrintExpr(op->index), op->index.type());
      std::string value = SSAGetID(PrintExpr(op->value), op->value.type());
      std::string vid = GetVarID(op->buffer_var.get());
      for (int i = 0; i < t.lanes(); ++i) {
        this->PrintIndent();
        Type elem_type = t.element_of();
        if (!HandleTypeMatch(op->buffer_var.get(), elem_type)) {
          stream << "((";
630 631 632 633 634 635 636
          if (op->buffer_var.get()->type.is_handle()) {
            auto it = alloc_storage_scope_.find(op->buffer_var.get());
            if (it != alloc_storage_scope_.end()) {
              PrintStorageScope(it->second, stream);
              stream << ' ';
            }
          }
637 638 639 640 641 642 643 644 645 646 647
          PrintType(elem_type, stream);
          stream << "*)" << vid << ')';
        } else {
          stream << vid;
        }
        stream << '[';
        PrintVecElemLoad(index, op->index.type(), i, stream);
        stream << "] = ";
        PrintVecElemLoad(value, op->value.type(), i, stream);
        stream << ";\n";
      }
648
      EndScope(vec_scope);
649
    }
650
  }
651 652
}

653
void CodeGenC::VisitExpr_(const Let* op, std::ostream& os) {  // NOLINT(*)
654 655 656 657 658 659 660
  CHECK(print_ssa_form_)
      << "LetExpr is only supported by print SSA form";
  std::string value = PrintExpr(op->value);
  CHECK(!var_idmap_.count(op->var.get()));
  var_idmap_[op->var.get()] = value;
}

661
void CodeGenC::VisitExpr_(const Ramp* op, std::ostream& os) {  // NOLINT(*)
662 663
  // constraint of current logic
  CHECK_EQ(op->base.type(), Int(32));
664 665 666 667 668 669 670
  os << "((int" << op->lanes << ")(";
  for (int i = 0; i < op->lanes; i++) {
    os << "(" << PrintExpr(op->base) << ")" << "+(" << PrintExpr(op->stride) << "*" << i <<")";
    if (i != op->lanes - 1)
      os << ", ";
  }
  os << "))";
671 672
}

673
void CodeGenC::VisitExpr_(const Broadcast* op, std::ostream& os) {   // NOLINT(*)
674
  LOG(FATAL) << "Broadcast: not supported ";
675 676
}

677
void CodeGenC::VisitExpr_(const Select* op, std::ostream& os) {  // NOLINT(*)
678 679 680 681 682 683 684
  os << "(";
  PrintExpr(op->condition, os);
  os << " ? ";
  PrintExpr(op->true_value, os);
  os << " : ";
  PrintExpr(op->false_value, os);
  os << ")";
685 686
}

687
void CodeGenC::VisitStmt_(const LetStmt* op) {
688 689 690 691 692 693
  std::string value = PrintExpr(op->value);
  if (print_ssa_form_) {
    CHECK(!var_idmap_.count(op->var.get()));
    var_idmap_[op->var.get()] = value;
  } else {
    PrintIndent();
694 695 696 697 698 699 700 701 702 703 704 705 706 707
    if (op->var.type() == Handle() &&
        handle_data_type_.count(op->var.get())) {
      PrintType(handle_data_type_.at(op->var.get()), stream);
      stream << "* "
             << AllocVarID(op->var.get())
             << " = (";
      PrintType(handle_data_type_.at(op->var.get()), stream);
      stream << "*)"  << value << ";\n";
    } else {
      PrintType(op->var.type(), this->stream);
      this->stream << ' '
                   << AllocVarID(op->var.get())
                   << " = " << value << ";\n";
    }
708 709 710 711
  }
  PrintStmt(op->body);
}

712
void CodeGenC::VisitStmt_(const Allocate* op) {
713
  CHECK(!is_zero(op->condition));
714 715 716 717 718 719 720 721 722 723 724 725 726
  std::string vid = AllocVarID(op->buffer_var.get());
  if (op->new_expr.defined()) {
    // Prefer global static allocation for the program
    CHECK_EQ(op->free_function, "nop");
    std::string new_data = PrintExpr(op->new_expr);
    this->PrintIndent();
    PrintType(op->type, stream);
    stream << "* "<< vid << '=' << new_data << ";\n";
  } else {
    this->PrintIndent();
    int32_t constant_size = op->constant_allocation_size();
    CHECK_GT(constant_size, 0)
        << "Can only handle constant size stack allocation for now";
727 728 729
    const Variable* buffer = op->buffer_var.as<Variable>();
    std::string scope = alloc_storage_scope_.at(buffer);
    PrintStorageScope(scope, stream);
730
    stream << ' ';
731 732
    PrintType(op->type, stream);
    stream << ' '<< vid << '['
733
           << constant_size << "];\n";
734
  }
735
  RegisterHandleType(op->buffer_var.get(), op->type);
736 737 738
  this->PrintStmt(op->body);
}

739
void CodeGenC::VisitStmt_(const AttrStmt* op) {
740
  if (op->attr_key == ir::attr::thread_extent) {
741 742
    IterVar iv(op->node.node_);
    if (iv->thread_tag.length() != 0) {
743
      if (!var_idmap_.count(iv->var.get())) {
744
        BindThreadIndex(iv);
745
      }
746
    }
747
  } else if (op->attr_key == ir::attr::storage_scope) {
748 749 750
    const Variable* v = op->node.as<Variable>();
    CHECK(v);
    alloc_storage_scope_[v] = op->value.as<StringImm>()->value;
751
  } else if (op->attr_key == ir::attr::volatile_scope) {
752 753 754
    const Variable* v = op->node.as<Variable>();
    CHECK(v);
    volatile_buf_.insert(v);
755 756 757 758
  }
  this->PrintStmt(op->body);
}

759
void CodeGenC::VisitStmt_(const AssertStmt* op) {
760 761 762 763 764 765 766 767 768
  std::string cond = PrintExpr(op->condition);
  PrintIndent();
  if (op->message.as<StringImm>()) {
    // GLOG style check
    stream << "CHECK(" << cond << ") << \""
           << op->message.as<StringImm>()->value << "\";\n";
  } else {
    stream << "assert(" << cond << ");\n";
  }
769
  this->PrintStmt(op->body);
770 771
}

772
void CodeGenC::VisitStmt_(const For* op) {
773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788
  std::string extent = PrintExpr(op->extent);
  PrintIndent();
  std::string vid = AllocVarID(op->loop_var.get());
  CHECK(is_zero(op->min));
  stream << "for (";
  PrintType(op->loop_var.type(), stream);
  stream << ' ' << vid << " = 0; "
            << vid << " < " << extent
            << "; ++" << vid << ") {\n";
  int for_scope = BeginScope();
  PrintStmt(op->body);
  this->EndScope(for_scope);
  PrintIndent();
  stream << "}\n";
}

789
void CodeGenC::VisitStmt_(const IfThenElse* op) {
790 791
  std::string cond = PrintExpr(op->condition);
  PrintIndent();
792 793 794 795 796
  if (cond[0] == '(' && cond[cond.length() - 1] == ')') {
    stream << "if " << cond << " {\n";
  } else {
    stream << "if (" << cond << ") {\n";
  }
797 798 799 800 801 802 803 804 805 806 807 808 809 810 811
  int then_scope = BeginScope();
  PrintStmt(op->then_case);
  this->EndScope(then_scope);

  if (op->else_case.defined()) {
    PrintIndent();
    stream << "} else {\n";
    int else_scope = BeginScope();
    PrintStmt(op->else_case);
    this->EndScope(else_scope);
  }
  PrintIndent();
  stream << "}\n";
}

812 813 814 815 816 817 818 819
void CodeGenC::VisitStmt_(const Block *op) {
  PrintStmt(op->first);
  if (op->rest.defined()) PrintStmt(op->rest);
}

void CodeGenC::VisitStmt_(const Evaluate *op) {
  if (is_const(op->value)) return;
  const Call* call = op->value.as<Call>();
820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
  if (call) {
    if (call->is_intrinsic(intrinsic::tvm_storage_sync)) {
      this->PrintStorageSync(call); return;
    } else if (call->is_intrinsic(intrinsic::tvm_struct_set)) {
      CHECK_EQ(call->args.size(), 4);
      std::string value = PrintExpr(call->args[3]);
      std::string ref = GetStructRef(
          call->args[3].type(),
          call->args[0],
          call->args[1],
          call->args[2].as<IntImm>()->value);
      this->PrintIndent();
      this->stream << ref << " = " << value << ";\n";
      return;
    }
835
  }
836 837 838
  std::string vid = this->PrintExpr(op->value);
  this->PrintIndent();
  this->stream << "(void)" << vid << ";\n";
839 840 841 842 843
}

void CodeGenC::VisitStmt_(const ProducerConsumer *op) {
  PrintStmt(op->body);
}
844

845 846
}  // namespace codegen
}  // namespace tvm