[NFC][OpenACC][CIR] Extract 'base' class for Recipe generation (#160603)

It was brought up on a previous review that the CIRGenOpenACCRecipe.h
file was getting too large. I noticed that the 'dependent on template
argument' parts were actually quite small, so I extract a base class in
this patch that allows me to implement it in the .cpp file, plus
minimize the amount of code that needs instantiating.

Author: erichkeane

clang/lib/CIR/CodeGen/CIRGenOpenACCRecipe.cpp

@@ -0,0 +1,316 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// Helperes to emit OpenACC clause recipes as CIR code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CIRGenOpenACCRecipe.h"
+
+namespace clang::CIRGen {
+mlir::Block *OpenACCRecipeBuilderBase::createRecipeBlock(mlir::Region &region,
+                                                         mlir::Type opTy,
+                                                         mlir::Location loc,
+                                                         size_t numBounds,
+                                                         bool isInit) {
+  llvm::SmallVector<mlir::Type> types;
+  types.reserve(numBounds + 2);
+  types.push_back(opTy);
+  // The init section is the only one that doesn't have TWO copies of the
+  // operation-type.  Copy has a to/from, and destroy has a
+  // 'reference'/'privatized' copy version.
+  if (!isInit)
+    types.push_back(opTy);
+
+  auto boundsTy = mlir::acc::DataBoundsType::get(&cgf.getMLIRContext());
+  for (size_t i = 0; i < numBounds; ++i)
+    types.push_back(boundsTy);
+
+  llvm::SmallVector<mlir::Location> locs{types.size(), loc};
+  return builder.createBlock(&region, region.end(), types, locs);
+}
+
+mlir::Value
+OpenACCRecipeBuilderBase::createBoundsLoop(mlir::Value subscriptedValue,
+                                           mlir::Value bound,
+                                           mlir::Location loc, bool inverse) {
+  mlir::Operation *bodyInsertLoc;
+
+  mlir::Type itrTy = cgf.cgm.convertType(cgf.getContext().UnsignedLongLongTy);
+  auto itrPtrTy = cir::PointerType::get(itrTy);
+  mlir::IntegerAttr itrAlign =
+      cgf.cgm.getSize(cgf.getContext().getTypeAlignInChars(
+          cgf.getContext().UnsignedLongLongTy));
+  auto idxType = mlir::IndexType::get(&cgf.getMLIRContext());
+
+  auto doSubscriptOp = [&](mlir::Value subVal,
+                           cir::LoadOp idxLoad) -> mlir::Value {
+    auto eltTy = cast<cir::PointerType>(subVal.getType()).getPointee();
+
+    if (auto arrayTy = dyn_cast<cir::ArrayType>(eltTy))
+      return builder.getArrayElement(loc, loc, subVal, arrayTy.getElementType(),
+                                     idxLoad.getResult(),
+                                     /*shouldDecay=*/true);
+
+    assert(isa<cir::PointerType>(eltTy));
+
+    auto eltLoad = cir::LoadOp::create(builder, loc, {subVal});
+
+    return cir::PtrStrideOp::create(builder, loc, eltLoad.getType(), eltLoad,
+                                    idxLoad.getResult())
+        .getResult();
+  };
+
+  auto forStmtBuilder = [&]() {
+    // get the lower and upper bound for iterating over.
+    auto lowerBoundVal =
+        mlir::acc::GetLowerboundOp::create(builder, loc, idxType, bound);
+    auto lbConversion = mlir::UnrealizedConversionCastOp::create(
+        builder, loc, itrTy, lowerBoundVal.getResult());
+    auto upperBoundVal =
+        mlir::acc::GetUpperboundOp::create(builder, loc, idxType, bound);
+    auto ubConversion = mlir::UnrealizedConversionCastOp::create(
+        builder, loc, itrTy, upperBoundVal.getResult());
+
+    // Create a memory location for the iterator.
+    auto itr =
+        cir::AllocaOp::create(builder, loc, itrPtrTy, itrTy, "iter", itrAlign);
+    // Store to the iterator: either lower bound, or if inverse loop, upper
+    // bound.
+    if (inverse) {
+      cir::ConstantOp constOne = builder.getConstInt(loc, itrTy, 1);
+
+      auto sub =
+          cir::BinOp::create(builder, loc, itrTy, cir::BinOpKind::Sub,
+                             ubConversion.getResult(0), constOne.getResult());
+
+      // Upperbound is exclusive, so subtract 1.
+      builder.CIRBaseBuilderTy::createStore(loc, sub.getResult(), itr);
+    } else {
+      // Lowerbound is inclusive, so we can include it.
+      builder.CIRBaseBuilderTy::createStore(loc, lbConversion.getResult(0),
+                                            itr);
+    }
+    // Save the 'end' iterator based on whether we are inverted or not. This
+    // end iterator never changes, so we can just get it and convert it, so no
+    // need to store/load/etc.
+    auto endItr = inverse ? lbConversion : ubConversion;
+
+    builder.createFor(
+        loc,
+        /*condBuilder=*/
+        [&](mlir::OpBuilder &b, mlir::Location loc) {
+          auto loadCur = cir::LoadOp::create(builder, loc, {itr});
+          // Use 'not equal' since we are just doing an increment/decrement.
+          auto cmp = builder.createCompare(
+              loc, inverse ? cir::CmpOpKind::ge : cir::CmpOpKind::lt,
+              loadCur.getResult(), endItr.getResult(0));
+          builder.createCondition(cmp);
+        },
+        /*bodyBuilder=*/
+        [&](mlir::OpBuilder &b, mlir::Location loc) {
+          auto load = cir::LoadOp::create(builder, loc, {itr});
+
+          if (subscriptedValue)
+            subscriptedValue = doSubscriptOp(subscriptedValue, load);
+          bodyInsertLoc = builder.createYield(loc);
+        },
+        /*stepBuilder=*/
+        [&](mlir::OpBuilder &b, mlir::Location loc) {
+          auto load = cir::LoadOp::create(builder, loc, {itr});
+          auto unary = cir::UnaryOp::create(builder, loc, load.getType(),
+                                            inverse ? cir::UnaryOpKind::Dec
+                                                    : cir::UnaryOpKind::Inc,
+                                            load.getResult());
+          builder.CIRBaseBuilderTy::createStore(loc, unary.getResult(), itr);
+          builder.createYield(loc);
+        });
+  };
+
+  cir::ScopeOp::create(builder, loc,
+                       [&](mlir::OpBuilder &b, mlir::Location loc) {
+                         forStmtBuilder();
+                         builder.createYield(loc);
+                       });
+
+  // Leave the insertion point to be inside the body, so we can loop over
+  // these things.
+  builder.setInsertionPoint(bodyInsertLoc);
+  return subscriptedValue;
+}
+
+mlir::acc::ReductionOperator
+OpenACCRecipeBuilderBase::convertReductionOp(OpenACCReductionOperator op) {
+  switch (op) {
+  case OpenACCReductionOperator::Addition:
+    return mlir::acc::ReductionOperator::AccAdd;
+  case OpenACCReductionOperator::Multiplication:
+    return mlir::acc::ReductionOperator::AccMul;
+  case OpenACCReductionOperator::Max:
+    return mlir::acc::ReductionOperator::AccMax;
+  case OpenACCReductionOperator::Min:
+    return mlir::acc::ReductionOperator::AccMin;
+  case OpenACCReductionOperator::BitwiseAnd:
+    return mlir::acc::ReductionOperator::AccIand;
+  case OpenACCReductionOperator::BitwiseOr:
+    return mlir::acc::ReductionOperator::AccIor;
+  case OpenACCReductionOperator::BitwiseXOr:
+    return mlir::acc::ReductionOperator::AccXor;
+  case OpenACCReductionOperator::And:
+    return mlir::acc::ReductionOperator::AccLand;
+  case OpenACCReductionOperator::Or:
+    return mlir::acc::ReductionOperator::AccLor;
+  case OpenACCReductionOperator::Invalid:
+    llvm_unreachable("invalid reduction operator");
+  }
+
+  llvm_unreachable("invalid reduction operator");
+}
+
+// This function generates the 'destroy' section for a recipe. Note
+// that this function is not 'insertion point' clean, in that it alters the
+// insertion point to be inside of the 'destroy' section of the recipe, but
+// doesn't restore it aftewards.
+void OpenACCRecipeBuilderBase::createRecipeDestroySection(
+    mlir::Location loc, mlir::Location locEnd, mlir::Value mainOp,
+    CharUnits alignment, QualType origType, size_t numBounds, QualType baseType,
+    mlir::Region &destroyRegion) {
+  mlir::Block *block = createRecipeBlock(destroyRegion, mainOp.getType(), loc,
+                                         numBounds, /*isInit=*/false);
+  builder.setInsertionPointToEnd(&destroyRegion.back());
+  CIRGenFunction::LexicalScope ls(cgf, loc, block);
+
+  mlir::Type elementTy =
+      mlir::cast<cir::PointerType>(mainOp.getType()).getPointee();
+  auto emitDestroy = [&](mlir::Value var, mlir::Type ty) {
+    Address addr{var, ty, alignment};
+    cgf.emitDestroy(addr, origType,
+                    cgf.getDestroyer(QualType::DK_cxx_destructor));
+  };
+
+  if (numBounds) {
+    mlir::OpBuilder::InsertionGuard guardCase(builder);
+    // Get the range of bounds arguments, which are all but the 1st 2. 1st is
+    // a 'reference', 2nd is the 'private' variant we need to destroy from.
+    llvm::MutableArrayRef<mlir::BlockArgument> boundsRange =
+        block->getArguments().drop_front(2);
+
+    mlir::Value subscriptedValue = block->getArgument(1);
+    for (mlir::BlockArgument boundArg : llvm::reverse(boundsRange))
+      subscriptedValue = createBoundsLoop(subscriptedValue, boundArg, loc,
+                                          /*inverse=*/true);
+
+    emitDestroy(subscriptedValue, cgf.cgm.convertType(origType));
+  } else {
+    // If we don't have any bounds, we can just destroy the variable directly.
+    // The destroy region has a signature of "original item, privatized item".
+    // So the 2nd item is the one that needs destroying, the former is just
+    // for reference and we don't really have a need for it at the moment.
+    emitDestroy(block->getArgument(1), elementTy);
+  }
+
+  mlir::acc::YieldOp::create(builder, locEnd);
+}
+
+// TODO: OpenACC: When we get this implemented for the reduction/firstprivate,
+// this might end up re-merging with createRecipeInitCopy.  For now, keep it
+// separate until we're sure what everything looks like to keep this as clean
+// as possible.
+void OpenACCRecipeBuilderBase::createPrivateInitRecipe(
+    mlir::Location loc, mlir::Location locEnd, SourceRange exprRange,
+    mlir::Value mainOp, mlir::acc::PrivateRecipeOp recipe, size_t numBounds,
+    llvm::ArrayRef<QualType> boundTypes, const VarDecl *allocaDecl,
+    QualType origType, const Expr *initExpr) {
+  assert(allocaDecl && "Required recipe variable not set?");
+  CIRGenFunction::DeclMapRevertingRAII declMapRAII{cgf, allocaDecl};
+
+  mlir::Block *block =
+      createRecipeBlock(recipe.getInitRegion(), mainOp.getType(), loc,
+                        numBounds, /*isInit=*/true);
+  builder.setInsertionPointToEnd(&recipe.getInitRegion().back());
+  CIRGenFunction::LexicalScope ls(cgf, loc, block);
+
+  const Type *allocaPointeeType =
+      allocaDecl->getType()->getPointeeOrArrayElementType();
+  // We are OK with no init for builtins, arrays of builtins, or pointers,
+  // else we should NYI so we know to go look for these.
+  if (cgf.getContext().getLangOpts().CPlusPlus && !allocaDecl->getInit() &&
+      !allocaDecl->getType()->isPointerType() &&
+      !allocaPointeeType->isBuiltinType() &&
+      !allocaPointeeType->isPointerType()) {
+    // If we don't have any initialization recipe, we failed during Sema to
+    // initialize this correctly. If we disable the
+    // Sema::TentativeAnalysisScopes in SemaOpenACC::CreateInitRecipe, it'll
+    // emit an error to tell us.  However, emitting those errors during
+    // production is a violation of the standard, so we cannot do them.
+    cgf.cgm.errorNYI(exprRange, "private default-init recipe");
+  }
+
+  if (!numBounds) {
+    // This is an 'easy' case, we just have to use the builtin init stuff to
+    // initialize this variable correctly.
+    CIRGenFunction::AutoVarEmission tempDeclEmission =
+        cgf.emitAutoVarAlloca(*allocaDecl, builder.saveInsertionPoint());
+    cgf.emitAutoVarInit(tempDeclEmission);
+  } else {
+    cgf.cgm.errorNYI(exprRange, "private-init with bounds");
+  }
+
+  mlir::acc::YieldOp::create(builder, locEnd);
+}
+
+void OpenACCRecipeBuilderBase::createFirstprivateRecipeCopy(
+    mlir::Location loc, mlir::Location locEnd, mlir::Value mainOp,
+    CIRGenFunction::AutoVarEmission tempDeclEmission,
+    mlir::acc::FirstprivateRecipeOp recipe, const VarDecl *varRecipe,
+    const VarDecl *temporary) {
+  mlir::Block *block =
+      createRecipeBlock(recipe.getCopyRegion(), mainOp.getType(), loc,
+                        /*numBounds=*/0, /*isInit=*/false);
+  builder.setInsertionPointToEnd(&recipe.getCopyRegion().back());
+  CIRGenFunction::LexicalScope ls(cgf, loc, block);
+
+  mlir::BlockArgument fromArg = block->getArgument(0);
+  mlir::BlockArgument toArg = block->getArgument(1);
+
+  mlir::Type elementTy =
+      mlir::cast<cir::PointerType>(mainOp.getType()).getPointee();
+
+  // Set the address of the emission to be the argument, so that we initialize
+  // that instead of the variable in the other block.
+  tempDeclEmission.setAllocatedAddress(
+      Address{toArg, elementTy, cgf.getContext().getDeclAlign(varRecipe)});
+  tempDeclEmission.EmittedAsOffload = true;
+
+  CIRGenFunction::DeclMapRevertingRAII declMapRAII{cgf, temporary};
+  cgf.setAddrOfLocalVar(
+      temporary,
+      Address{fromArg, elementTy, cgf.getContext().getDeclAlign(varRecipe)});
+
+  cgf.emitAutoVarInit(tempDeclEmission);
+  mlir::acc::YieldOp::create(builder, locEnd);
+}
+// This function generates the 'combiner' section for a reduction recipe. Note
+// that this function is not 'insertion point' clean, in that it alters the
+// insertion point to be inside of the 'combiner' section of the recipe, but
+// doesn't restore it aftewards.
+void OpenACCRecipeBuilderBase::createReductionRecipeCombiner(
+    mlir::Location loc, mlir::Location locEnd, mlir::Value mainOp,
+    mlir::acc::ReductionRecipeOp recipe) {
+  mlir::Block *block = builder.createBlock(
+      &recipe.getCombinerRegion(), recipe.getCombinerRegion().end(),
+      {mainOp.getType(), mainOp.getType()}, {loc, loc});
+  builder.setInsertionPointToEnd(&recipe.getCombinerRegion().back());
+  CIRGenFunction::LexicalScope ls(cgf, loc, block);
+
+  mlir::BlockArgument lhsArg = block->getArgument(0);
+
+  mlir::acc::YieldOp::create(builder, locEnd, lhsArg);
+}
+
+} // namespace clang::CIRGen