mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-10-25 22:12:57 +02:00
928c33c531
Note: I'm am not trying to describe what "should be"; I'm only describing what is true today. This came out of my recent question to llvm-dev titled: When can the dominator tree not contain a node for a basic block? Differential Revision: http://reviews.llvm.org/D13078 llvm-svn: 248417
255 lines
8.2 KiB
C++
255 lines
8.2 KiB
C++
//===- Dominators.h - Dominator Info Calculation ----------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file defines the DominatorTree class, which provides fast and efficient
|
|
// dominance queries.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_IR_DOMINATORS_H
|
|
#define LLVM_IR_DOMINATORS_H
|
|
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/ADT/DepthFirstIterator.h"
|
|
#include "llvm/ADT/GraphTraits.h"
|
|
#include "llvm/ADT/SmallPtrSet.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/IR/BasicBlock.h"
|
|
#include "llvm/IR/CFG.h"
|
|
#include "llvm/IR/Function.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Support/Compiler.h"
|
|
#include "llvm/Support/GenericDomTree.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
#include <algorithm>
|
|
|
|
namespace llvm {
|
|
|
|
// FIXME: Replace this brittle forward declaration with the include of the new
|
|
// PassManager.h when doing so doesn't break the PassManagerBuilder.
|
|
template <typename IRUnitT> class AnalysisManager;
|
|
class PreservedAnalyses;
|
|
|
|
extern template class DomTreeNodeBase<BasicBlock>;
|
|
extern template class DominatorTreeBase<BasicBlock>;
|
|
|
|
extern template void Calculate<Function, BasicBlock *>(
|
|
DominatorTreeBase<GraphTraits<BasicBlock *>::NodeType> &DT, Function &F);
|
|
extern template void Calculate<Function, Inverse<BasicBlock *>>(
|
|
DominatorTreeBase<GraphTraits<Inverse<BasicBlock *>>::NodeType> &DT,
|
|
Function &F);
|
|
|
|
typedef DomTreeNodeBase<BasicBlock> DomTreeNode;
|
|
|
|
class BasicBlockEdge {
|
|
const BasicBlock *Start;
|
|
const BasicBlock *End;
|
|
public:
|
|
BasicBlockEdge(const BasicBlock *Start_, const BasicBlock *End_) :
|
|
Start(Start_), End(End_) { }
|
|
const BasicBlock *getStart() const {
|
|
return Start;
|
|
}
|
|
const BasicBlock *getEnd() const {
|
|
return End;
|
|
}
|
|
bool isSingleEdge() const;
|
|
};
|
|
|
|
/// \brief Concrete subclass of DominatorTreeBase that is used to compute a
|
|
/// normal dominator tree.
|
|
///
|
|
/// Definition: A block is said to be forward statically reachable if there is
|
|
/// a path from the entry of the function to the block. A statically reachable
|
|
/// block may become statically unreachable during optimization.
|
|
///
|
|
/// A forward unreachable block may appear in the dominator tree, or it may
|
|
/// not. If it does, dominance queries will return results as if all reachable
|
|
/// blocks dominate it. When asking for a Node corresponding to a potentially
|
|
/// unreachable block, calling code must handle the case where the block was
|
|
/// unreachable and the result of getNode() is nullptr.
|
|
///
|
|
/// Generally, a block known to be unreachable when the dominator tree is
|
|
/// constructed will not be in the tree. One which becomes unreachable after
|
|
/// the dominator tree is initially constructed may still exist in the tree,
|
|
/// even if the tree is properly updated. Calling code should not rely on the
|
|
/// preceding statements; this is stated only to assist human understanding.
|
|
class DominatorTree : public DominatorTreeBase<BasicBlock> {
|
|
public:
|
|
typedef DominatorTreeBase<BasicBlock> Base;
|
|
|
|
DominatorTree() : DominatorTreeBase<BasicBlock>(false) {}
|
|
explicit DominatorTree(Function &F) : DominatorTreeBase<BasicBlock>(false) {
|
|
recalculate(F);
|
|
}
|
|
|
|
DominatorTree(DominatorTree &&Arg)
|
|
: Base(std::move(static_cast<Base &>(Arg))) {}
|
|
DominatorTree &operator=(DominatorTree &&RHS) {
|
|
Base::operator=(std::move(static_cast<Base &>(RHS)));
|
|
return *this;
|
|
}
|
|
|
|
/// \brief Returns *false* if the other dominator tree matches this dominator
|
|
/// tree.
|
|
inline bool compare(const DominatorTree &Other) const {
|
|
const DomTreeNode *R = getRootNode();
|
|
const DomTreeNode *OtherR = Other.getRootNode();
|
|
|
|
if (!R || !OtherR || R->getBlock() != OtherR->getBlock())
|
|
return true;
|
|
|
|
if (Base::compare(Other))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
// Ensure base-class overloads are visible.
|
|
using Base::dominates;
|
|
|
|
/// \brief Return true if Def dominates a use in User.
|
|
///
|
|
/// This performs the special checks necessary if Def and User are in the same
|
|
/// basic block. Note that Def doesn't dominate a use in Def itself!
|
|
bool dominates(const Instruction *Def, const Use &U) const;
|
|
bool dominates(const Instruction *Def, const Instruction *User) const;
|
|
bool dominates(const Instruction *Def, const BasicBlock *BB) const;
|
|
bool dominates(const BasicBlockEdge &BBE, const Use &U) const;
|
|
bool dominates(const BasicBlockEdge &BBE, const BasicBlock *BB) const;
|
|
|
|
// Ensure base class overloads are visible.
|
|
using Base::isReachableFromEntry;
|
|
|
|
/// \brief Provide an overload for a Use.
|
|
bool isReachableFromEntry(const Use &U) const;
|
|
|
|
/// \brief Verify the correctness of the domtree by re-computing it.
|
|
///
|
|
/// This should only be used for debugging as it aborts the program if the
|
|
/// verification fails.
|
|
void verifyDomTree() const;
|
|
};
|
|
|
|
//===-------------------------------------
|
|
// DominatorTree GraphTraits specializations so the DominatorTree can be
|
|
// iterable by generic graph iterators.
|
|
|
|
template <class Node, class ChildIterator> struct DomTreeGraphTraitsBase {
|
|
typedef Node NodeType;
|
|
typedef ChildIterator ChildIteratorType;
|
|
typedef df_iterator<Node *, SmallPtrSet<NodeType *, 8>> nodes_iterator;
|
|
|
|
static NodeType *getEntryNode(NodeType *N) { return N; }
|
|
static inline ChildIteratorType child_begin(NodeType *N) {
|
|
return N->begin();
|
|
}
|
|
static inline ChildIteratorType child_end(NodeType *N) { return N->end(); }
|
|
|
|
static nodes_iterator nodes_begin(NodeType *N) {
|
|
return df_begin(getEntryNode(N));
|
|
}
|
|
|
|
static nodes_iterator nodes_end(NodeType *N) {
|
|
return df_end(getEntryNode(N));
|
|
}
|
|
};
|
|
|
|
template <>
|
|
struct GraphTraits<DomTreeNode *>
|
|
: public DomTreeGraphTraitsBase<DomTreeNode, DomTreeNode::iterator> {};
|
|
|
|
template <>
|
|
struct GraphTraits<const DomTreeNode *>
|
|
: public DomTreeGraphTraitsBase<const DomTreeNode,
|
|
DomTreeNode::const_iterator> {};
|
|
|
|
template <> struct GraphTraits<DominatorTree*>
|
|
: public GraphTraits<DomTreeNode*> {
|
|
static NodeType *getEntryNode(DominatorTree *DT) {
|
|
return DT->getRootNode();
|
|
}
|
|
|
|
static nodes_iterator nodes_begin(DominatorTree *N) {
|
|
return df_begin(getEntryNode(N));
|
|
}
|
|
|
|
static nodes_iterator nodes_end(DominatorTree *N) {
|
|
return df_end(getEntryNode(N));
|
|
}
|
|
};
|
|
|
|
/// \brief Analysis pass which computes a \c DominatorTree.
|
|
class DominatorTreeAnalysis {
|
|
public:
|
|
/// \brief Provide the result typedef for this analysis pass.
|
|
typedef DominatorTree Result;
|
|
|
|
/// \brief Opaque, unique identifier for this analysis pass.
|
|
static void *ID() { return (void *)&PassID; }
|
|
|
|
/// \brief Run the analysis pass over a function and produce a dominator tree.
|
|
DominatorTree run(Function &F);
|
|
|
|
/// \brief Provide access to a name for this pass for debugging purposes.
|
|
static StringRef name() { return "DominatorTreeAnalysis"; }
|
|
|
|
private:
|
|
static char PassID;
|
|
};
|
|
|
|
/// \brief Printer pass for the \c DominatorTree.
|
|
class DominatorTreePrinterPass {
|
|
raw_ostream &OS;
|
|
|
|
public:
|
|
explicit DominatorTreePrinterPass(raw_ostream &OS);
|
|
PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
|
|
|
|
static StringRef name() { return "DominatorTreePrinterPass"; }
|
|
};
|
|
|
|
/// \brief Verifier pass for the \c DominatorTree.
|
|
struct DominatorTreeVerifierPass {
|
|
PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
|
|
|
|
static StringRef name() { return "DominatorTreeVerifierPass"; }
|
|
};
|
|
|
|
/// \brief Legacy analysis pass which computes a \c DominatorTree.
|
|
class DominatorTreeWrapperPass : public FunctionPass {
|
|
DominatorTree DT;
|
|
|
|
public:
|
|
static char ID;
|
|
|
|
DominatorTreeWrapperPass() : FunctionPass(ID) {
|
|
initializeDominatorTreeWrapperPassPass(*PassRegistry::getPassRegistry());
|
|
}
|
|
|
|
DominatorTree &getDomTree() { return DT; }
|
|
const DominatorTree &getDomTree() const { return DT; }
|
|
|
|
bool runOnFunction(Function &F) override;
|
|
|
|
void verifyAnalysis() const override;
|
|
|
|
void getAnalysisUsage(AnalysisUsage &AU) const override {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
void releaseMemory() override { DT.releaseMemory(); }
|
|
|
|
void print(raw_ostream &OS, const Module *M = nullptr) const override;
|
|
};
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|