clang/lib/CIR/CodeGen/CIRGenExpr.cpp

//===----------------------------------------------------------------------===//
//
// 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 contains code to emit Expr nodes as CIR code.
//
//===----------------------------------------------------------------------===//

#include "Address.h"
#include "CIRGenFunction.h"
#include "CIRGenValue.h"
#include "mlir/IR/BuiltinAttributes.h"
#include "clang/AST/Attr.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/CIR/Dialect/IR/CIRDialect.h"
#include "clang/CIR/MissingFeatures.h"

using namespace clang;
using namespace clang::CIRGen;
using namespace cir;

void CIRGenFunction::emitStoreThroughLValue(RValue src, LValue dst,
                                            bool isInit) {
  if (!dst.isSimple()) {
    cgm.errorNYI(dst.getPointer().getLoc(),
                 "emitStoreThroughLValue: non-simple lvalue");
    return;
  }

  assert(!cir::MissingFeatures::opLoadStoreObjC());

  assert(src.isScalar() && "Can't emit an aggregate store with this method");
  emitStoreOfScalar(src.getScalarVal(), dst, isInit);
}

void CIRGenFunction::emitStoreOfScalar(mlir::Value value, Address addr,
                                       bool isVolatile, QualType ty,
                                       bool isInit, bool isNontemporal) {
  assert(!cir::MissingFeatures::opLoadStoreThreadLocal());

  if (ty->getAs<clang::VectorType>()) {
    cgm.errorNYI(addr.getPointer().getLoc(), "emitStoreOfScalar vector type");
    return;
  }

  value = emitToMemory(value, ty);

  assert(!cir::MissingFeatures::opLoadStoreAtomic());

  // Update the alloca with more info on initialization.
  assert(addr.getPointer() && "expected pointer to exist");
  auto srcAlloca =
      dyn_cast_or_null<cir::AllocaOp>(addr.getPointer().getDefiningOp());
  if (currVarDecl && srcAlloca) {
    const VarDecl *vd = currVarDecl;
    assert(vd && "VarDecl expected");
    if (vd->hasInit())
      srcAlloca.setInitAttr(mlir::UnitAttr::get(&getMLIRContext()));
  }

  assert(currSrcLoc && "must pass in source location");
  builder.createStore(*currSrcLoc, value, addr.getPointer() /*, isVolatile*/);

  if (isNontemporal) {
    cgm.errorNYI(addr.getPointer().getLoc(), "emitStoreOfScalar nontemporal");
    return;
  }

  assert(!cir::MissingFeatures::opTBAA());
}

mlir::Value CIRGenFunction::emitToMemory(mlir::Value value, QualType ty) {
  // Bool has a different representation in memory than in registers,
  // but in ClangIR, it is simply represented as a cir.bool value.
  // This function is here as a placeholder for possible future changes.
  return value;
}

void CIRGenFunction::emitStoreOfScalar(mlir::Value value, LValue lvalue,
                                       bool isInit) {
  if (lvalue.getType()->isConstantMatrixType()) {
    assert(0 && "NYI: emitStoreOfScalar constant matrix type");
    return;
  }

  emitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
                    lvalue.getType(), isInit, /*isNontemporal=*/false);
}

mlir::Value CIRGenFunction::emitLoadOfScalar(LValue lvalue,
                                             SourceLocation loc) {
  assert(!cir::MissingFeatures::opLoadStoreThreadLocal());
  assert(!cir::MissingFeatures::opLoadEmitScalarRangeCheck());
  assert(!cir::MissingFeatures::opLoadBooleanRepresentation());

  Address addr = lvalue.getAddress();
  mlir::Type eltTy = addr.getElementType();

  mlir::Value ptr = addr.getPointer();
  if (mlir::isa<cir::VoidType>(eltTy))
    cgm.errorNYI(loc, "emitLoadOfScalar: void type");

  mlir::Value loadOp = builder.CIRBaseBuilderTy::createLoad(
      getLoc(loc), ptr, false /*isVolatile*/);

  return loadOp;
}

/// Given an expression that represents a value lvalue, this
/// method emits the address of the lvalue, then loads the result as an rvalue,
/// returning the rvalue.
RValue CIRGenFunction::emitLoadOfLValue(LValue lv, SourceLocation loc) {
  assert(!lv.getType()->isFunctionType());
  assert(!(lv.getType()->isConstantMatrixType()) && "not implemented");

  if (lv.isSimple())
    return RValue::get(emitLoadOfScalar(lv, loc));

  cgm.errorNYI(loc, "emitLoadOfLValue");
  return RValue::get(nullptr);
}

LValue CIRGenFunction::emitDeclRefLValue(const DeclRefExpr *e) {
  const NamedDecl *nd = e->getDecl();
  QualType ty = e->getType();

  assert(e->isNonOdrUse() != NOUR_Unevaluated &&
         "should not emit an unevaluated operand");

  if (const auto *vd = dyn_cast<VarDecl>(nd)) {
    // Checks for omitted feature handling
    assert(!cir::MissingFeatures::opAllocaStaticLocal());
    assert(!cir::MissingFeatures::opAllocaNonGC());
    assert(!cir::MissingFeatures::opAllocaImpreciseLifetime());
    assert(!cir::MissingFeatures::opAllocaTLS());
    assert(!cir::MissingFeatures::opAllocaOpenMPThreadPrivate());
    assert(!cir::MissingFeatures::opAllocaEscapeByReference());

    // Check if this is a global variable
    if (vd->hasLinkage() || vd->isStaticDataMember())
      cgm.errorNYI(vd->getSourceRange(), "emitDeclRefLValue: global variable");

    Address addr = Address::invalid();

    // The variable should generally be present in the local decl map.
    auto iter = LocalDeclMap.find(vd);
    if (iter != LocalDeclMap.end()) {
      addr = iter->second;
    } else {
      // Otherwise, it might be static local we haven't emitted yet for some
      // reason; most likely, because it's in an outer function.
      cgm.errorNYI(vd->getSourceRange(), "emitDeclRefLValue: static local");
    }

    return LValue::makeAddr(addr, ty);
  }

  cgm.errorNYI(e->getSourceRange(), "emitDeclRefLValue: unhandled decl type");
  return LValue();
}

mlir::Value CIRGenFunction::emitAlloca(StringRef name, mlir::Type ty,
                                       mlir::Location loc,
                                       CharUnits alignment) {
  mlir::Block *entryBlock = getCurFunctionEntryBlock();

  // CIR uses its own alloca address space rather than follow the target data
  // layout like original CodeGen. The data layout awareness should be done in
  // the lowering pass instead.
  assert(!cir::MissingFeatures::addressSpace());
  cir::PointerType localVarPtrTy = builder.getPointerTo(ty);
  mlir::IntegerAttr alignIntAttr = cgm.getSize(alignment);

  mlir::Value addr;
  {
    mlir::OpBuilder::InsertionGuard guard(builder);
    builder.restoreInsertionPoint(builder.getBestAllocaInsertPoint(entryBlock));
    addr = builder.createAlloca(loc, /*addr type*/ localVarPtrTy,
                                /*var type*/ ty, name, alignIntAttr);
    assert(!cir::MissingFeatures::astVarDeclInterface());
  }
  return addr;
}

/// This creates an alloca and inserts it  at the current insertion point of the
/// builder.
Address CIRGenFunction::createTempAlloca(mlir::Type ty, CharUnits align,
                                         mlir::Location loc,
                                         const Twine &name) {
  mlir::Value alloca = emitAlloca(name.str(), ty, loc, align);
  return Address(alloca, ty, align);
}