llvm/llvm/lib/Transforms/Utils/SSAUpdaterBulk.cpp

//===- SSAUpdaterBulk.cpp - Unstructured SSA Update Tool ------------------===//
//
// 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 file implements the SSAUpdaterBulk class.
//
//===----------------------------------------------------------------------===//

#include "llvm/Transforms/Utils/SSAUpdaterBulk.h"
#include "llvm/Analysis/IteratedDominanceFrontier.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/Value.h"

usingnamespacellvm;

#define DEBUG_TYPE …

/// Helper function for finding a block which should have a value for the given
/// user. For PHI-nodes this block is the corresponding predecessor, for other
/// instructions it's their parent block.
static BasicBlock *getUserBB(Use *U) { … }

/// Add a new variable to the SSA rewriter. This needs to be called before
/// AddAvailableValue or AddUse calls.
unsigned SSAUpdaterBulk::AddVariable(StringRef Name, Type *Ty) { … }

/// Indicate that a rewritten value is available in the specified block with the
/// specified value.
void SSAUpdaterBulk::AddAvailableValue(unsigned Var, BasicBlock *BB, Value *V) { … }

/// Record a use of the symbolic value. This use will be updated with a
/// rewritten value when RewriteAllUses is called.
void SSAUpdaterBulk::AddUse(unsigned Var, Use *U) { … }

// Compute value at the given block BB. We either should already know it, or we
// should be able to recursively reach it going up dominator tree.
Value *SSAUpdaterBulk::computeValueAt(BasicBlock *BB, RewriteInfo &R,
                                      DominatorTree *DT) { … }

/// Given sets of UsingBlocks and DefBlocks, compute the set of LiveInBlocks.
/// This is basically a subgraph limited by DefBlocks and UsingBlocks.
static void
ComputeLiveInBlocks(const SmallPtrSetImpl<BasicBlock *> &UsingBlocks,
                    const SmallPtrSetImpl<BasicBlock *> &DefBlocks,
                    SmallPtrSetImpl<BasicBlock *> &LiveInBlocks,
                    PredIteratorCache &PredCache) { … }

/// Perform all the necessary updates, including new PHI-nodes insertion and the
/// requested uses update.
void SSAUpdaterBulk::RewriteAllUses(DominatorTree *DT,
                                    SmallVectorImpl<PHINode *> *InsertedPHIs) { … }