EmitCEmissionPatterns.cpp

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//===- EmitCEmissionPatterns.cpp - EmitC Dialect Emission Patterns --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This implements the emission patterns for the emitc dialect.
//
//===----------------------------------------------------------------------===//
 
#include "EmitCEmissionPatterns.h"
#include "../EmissionPrinter.h"
#include "mlir/Dialect/EmitC/IR/EmitC.h"
#include "llvm/ADT/SmallString.h"
 
using namespace mlir::emitc;
using namespace circt;
using namespace circt::ExportSystemC;
 
//===----------------------------------------------------------------------===//
// Operation emission patterns.
//===----------------------------------------------------------------------===//
 
namespace {
/// Emit emitc.include operations.
struct IncludeEmitter : OpEmissionPattern<IncludeOp> {
  using OpEmissionPattern::OpEmissionPattern;
 
  void emitStatement(IncludeOp op, EmissionPrinter &p) override {
    p << "#include " << (op.getIsStandardInclude() ? "<" : "\"")
      << op.getInclude() << (op.getIsStandardInclude() ? ">" : "\"") << "\n";
  }
};
 
/// Emit emitc.apply operations.
struct ApplyOpEmitter : OpEmissionPattern<ApplyOp> {
  using OpEmissionPattern::OpEmissionPattern;
 
  MatchResult matchInlinable(Value value) override {
    if (value.getDefiningOp<ApplyOp>()) {
      // We would need to check the 'applicableOperator' to select the
      // precedence to return. However, since the dereference and address_of
      // operators have the same precedence, we can omit that (for better
      // performance).
      return Precedence::ADDRESS_OF;
    }
    return {};
  }
 
  void emitInlined(Value value, EmissionPrinter &p) override {
    auto applyOp = value.getDefiningOp<ApplyOp>();
    p << applyOp.getApplicableOperator();
    p.getInlinable(applyOp.getOperand())
        .emitWithParensOnLowerPrecedence(Precedence::ADDRESS_OF);
  }
};
 
/// Emit emitc.call operations. Only calls with 0 or 1 results are supported.
/// Calls with no result are emitted as statements whereas calls with exactly
/// one result are always inlined no matter whether it is a pure function or has
/// side effects. To make sure that calls with side effects are not reordered
/// with interferring operations, a pre-pass has to emit VariableOp operations
/// with the result of the call as initial value.
class CallOpEmitter : public OpEmissionPattern<CallOpaqueOp> {
public:
  using OpEmissionPattern::OpEmissionPattern;
 
  MatchResult matchInlinable(Value value) override {
    if (auto callOp = value.getDefiningOp<CallOpaqueOp>()) {
      // TODO: template arguments not supported for now.
      if (callOp->getNumResults() == 1 && !callOp.getTemplateArgs())
        return Precedence::FUNCTION_CALL;
    }
    return {};
  }
 
  void emitInlined(Value value, EmissionPrinter &p) override {
    printCallOp(value.getDefiningOp<CallOpaqueOp>(), p);
  }
 
  bool matchStatement(Operation *op) override {
    // TODO: template arguments not supported for now.
    if (auto callOp = dyn_cast<CallOpaqueOp>(op))
      return callOp->getNumResults() <= 1 && !callOp.getTemplateArgs();
    return false;
  }
 
  void emitStatement(CallOpaqueOp callOp, EmissionPrinter &p) override {
    if (callOp->getNumResults() != 0)
      return;
 
    printCallOp(callOp, p);
    p << ";\n";
  }
 
private:
  void printCallOp(CallOpaqueOp callOp, EmissionPrinter &p) {
    p << callOp.getCallee();
 
    p << "(";
 
    if (!callOp.getArgs()) {
      llvm::interleaveComma(callOp.getOperands(), p, [&](Value operand) {
        p.getInlinable(operand).emitWithParensOnLowerPrecedence(
            Precedence::COMMA);
      });
    } else {
      llvm::interleaveComma(callOp.getArgs().value(), p, [&](Attribute attr) {
        if (auto idx = dyn_cast<IntegerAttr>(attr)) {
          if (isa<IndexType>(idx.getType())) {
            p.getInlinable(callOp.getOperands()[idx.getInt()])
                .emitWithParensOnLowerPrecedence(Precedence::COMMA);
            return;
          }
        }
 
        p.emitAttr(attr);
      });
    }
 
    p << ")";
  }
};
 
/// Emit emitc.cast operations.
struct CastOpEmitter : OpEmissionPattern<CastOp> {
  using OpEmissionPattern::OpEmissionPattern;
 
  MatchResult matchInlinable(Value value) override {
    if (value.getDefiningOp<CastOp>())
      return Precedence::CAST;
    return {};
  }
 
  void emitInlined(Value value, EmissionPrinter &p) override {
    auto castOp = value.getDefiningOp<CastOp>();
    p << "(";
    p.emitType(castOp.getDest().getType());
    p << ") ";
    p.getInlinable(castOp.getSource())
        .emitWithParensOnLowerPrecedence(Precedence::CAST);
  }
};
 
/// Emit emitc.constant operations.
struct ConstantEmitter : OpEmissionPattern<ConstantOp> {
  using OpEmissionPattern::OpEmissionPattern;
 
  MatchResult matchInlinable(Value value) override {
    if (value.getDefiningOp<ConstantOp>())
      return Precedence::LIT;
    return {};
  }
 
  void emitInlined(Value value, EmissionPrinter &p) override {
    p.emitAttr(value.getDefiningOp<ConstantOp>().getValue());
  }
};
} // namespace
 
//===----------------------------------------------------------------------===//
// Type emission patterns.
//===----------------------------------------------------------------------===//
 
namespace {
/// Emit an emitc.opaque type by just printing the contained string without
/// quotation marks.
struct OpaqueTypeEmitter : TypeEmissionPattern<OpaqueType> {
  void emitType(OpaqueType type, EmissionPrinter &p) override {
    p << type.getValue();
  }
};
 
/// Emit an emitc.ptr type.
struct PointerTypeEmitter : TypeEmissionPattern<PointerType> {
  void emitType(PointerType type, EmissionPrinter &p) override {
    p.emitType(type.getPointee());
    p << "*";
  }
};
} // namespace
 
namespace {
 
/// Emit an emitc.opaque attribute by just printing the contained string without
/// quotation marks.
struct OpaqueAttrEmitter : AttrEmissionPattern<OpaqueAttr> {
  void emitAttr(OpaqueAttr attr, EmissionPrinter &p) override {
    p << attr.getValue();
  }
};
 
} // namespace
 
//===----------------------------------------------------------------------===//
// Register Operation and Type emission patterns.
//===----------------------------------------------------------------------===//
 
void circt::ExportSystemC::populateEmitCOpEmitters(
    OpEmissionPatternSet &patterns, MLIRContext *context) {
  patterns.add<IncludeEmitter, ApplyOpEmitter, CallOpEmitter, CastOpEmitter,
               ConstantEmitter>(context);
}
 
void circt::ExportSystemC::populateEmitCTypeEmitters(
    TypeEmissionPatternSet &patterns) {
  patterns.add<OpaqueTypeEmitter, PointerTypeEmitter>();
}
 
void circt::ExportSystemC::populateEmitCAttrEmitters(
    AttrEmissionPatternSet &patterns) {
  patterns.add<OpaqueAttrEmitter>();
}