Refactor implementation of Statement class heirarchy to use statement block.
Use LLVM double-link with parent list to store statements within a block.
PiperOrigin-RevId: 204515541
diff --git a/lib/IR/Statement.cpp b/lib/IR/Statement.cpp
new file mode 100644
index 0000000..336cf7a
--- /dev/null
+++ b/lib/IR/Statement.cpp
@@ -0,0 +1,119 @@
+//===- Statement.cpp - MLIR Statement Classes ----------------------------===//
+//
+// Copyright 2019 The MLIR Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// =============================================================================
+
+#include "mlir/IR/MLFunction.h"
+#include "mlir/IR/Statements.h"
+using namespace mlir;
+
+//===----------------------------------------------------------------------===//
+// Statement
+//===------------------------------------------------------------------===//
+
+// Statements are deleted through the destroy() member because we don't have
+// a virtual destructor.
+Statement::~Statement() {
+ assert(block == nullptr && "statement destroyed but still in a block");
+}
+
+/// Destroy this statement or one of its subclasses.
+void Statement::destroy(Statement *stmt) {
+ switch (stmt->getKind()) {
+ case Kind::Operation:
+ delete cast<OperationStmt>(stmt);
+ break;
+ case Kind::For:
+ delete cast<ForStmt>(stmt);
+ break;
+ case Kind::If:
+ delete cast<IfStmt>(stmt);
+ break;
+ }
+}
+
+MLFunction *Statement::getFunction() const {
+ return this->getBlock()->getFunction();
+}
+
+//===----------------------------------------------------------------------===//
+// ilist_traits for Statement
+//===----------------------------------------------------------------------===//
+
+StmtBlock *llvm::ilist_traits<::mlir::Statement>::getContainingBlock() {
+ size_t Offset(
+ size_t(&((StmtBlock *)nullptr->*StmtBlock::getSublistAccess(nullptr))));
+ iplist<Statement> *Anchor(static_cast<iplist<Statement> *>(this));
+ return reinterpret_cast<StmtBlock *>(reinterpret_cast<char *>(Anchor) -
+ Offset);
+}
+
+/// This is a trait method invoked when a statement is added to a block. We
+/// keep the block pointer up to date.
+void llvm::ilist_traits<::mlir::Statement>::addNodeToList(Statement *stmt) {
+ assert(!stmt->getBlock() && "already in a statement block!");
+ stmt->block = getContainingBlock();
+}
+
+/// This is a trait method invoked when a statement is removed from a block.
+/// We keep the block pointer up to date.
+void llvm::ilist_traits<::mlir::Statement>::removeNodeFromList(
+ Statement *stmt) {
+ assert(stmt->block && "not already in a statement block!");
+ stmt->block = nullptr;
+}
+
+/// This is a trait method invoked when a statement is moved from one block
+/// to another. We keep the block pointer up to date.
+void llvm::ilist_traits<::mlir::Statement>::transferNodesFromList(
+ ilist_traits<Statement> &otherList, stmt_iterator first,
+ stmt_iterator last) {
+ // If we are transferring statements within the same block, the block
+ // pointer doesn't need to be updated.
+ StmtBlock *curParent = getContainingBlock();
+ if (curParent == otherList.getContainingBlock())
+ return;
+
+ // Update the 'block' member of each statement.
+ for (; first != last; ++first)
+ first->block = curParent;
+}
+
+/// Remove this statement from its StmtBlock and delete it.
+void Statement::eraseFromBlock() {
+ assert(getBlock() && "Statement has no block");
+ getBlock()->getStatements().erase(this);
+}
+
+//===----------------------------------------------------------------------===//
+// IfClause
+//===----------------------------------------------------------------------===//
+
+IfClause::IfClause(IfStmt *stmt) : StmtBlock(stmt) {
+ assert(stmt != nullptr && "If clause must have non-null parent");
+}
+
+IfStmt *IfClause::getIf() const { return static_cast<IfStmt *>(parent); }
+
+//===----------------------------------------------------------------------===//
+// IfStmt
+//===----------------------------------------------------------------------===//
+
+IfStmt::~IfStmt() {
+ // TODO: correctly delete StmtBlocks under then and else clauses
+ delete thenClause;
+ if (elseClause != nullptr)
+ delete elseClause;
+}