llvm-6502/include/llvm/CodeGen/MachineBasicBlock.h
Dan Gohman 968dc7a207 Reapply 68073, with fixes. EH Landing-pad basic blocks are not
entered via fall-through. Don't miss fallthroughs from blocks
terminated by conditional branches. Also, move
isOnlyReachableByFallthrough out of line.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68129 91177308-0d34-0410-b5e6-96231b3b80d8
2009-03-31 18:39:13 +00:00

415 lines
17 KiB
C++

//===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Collect the sequence of machine instructions for a basic block.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
#define LLVM_CODEGEN_MACHINEBASICBLOCK_H
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/Support/Streams.h"
namespace llvm {
class BasicBlock;
class MachineFunction;
template <>
struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
private:
mutable ilist_node<MachineInstr> Sentinel;
// this is only set by the MachineBasicBlock owning the LiveList
friend class MachineBasicBlock;
MachineBasicBlock* Parent;
public:
MachineInstr *createSentinel() const {
return static_cast<MachineInstr*>(&Sentinel);
}
void destroySentinel(MachineInstr *) const {}
MachineInstr *provideInitialHead() const { return createSentinel(); }
MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); }
static void noteHead(MachineInstr*, MachineInstr*) {}
void addNodeToList(MachineInstr* N);
void removeNodeFromList(MachineInstr* N);
void transferNodesFromList(ilist_traits &SrcTraits,
ilist_iterator<MachineInstr> first,
ilist_iterator<MachineInstr> last);
void deleteNode(MachineInstr *N);
private:
void createNode(const MachineInstr &);
};
class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
typedef ilist<MachineInstr> Instructions;
Instructions Insts;
const BasicBlock *BB;
int Number;
MachineFunction *xParent;
/// Predecessors/Successors - Keep track of the predecessor / successor
/// basicblocks.
std::vector<MachineBasicBlock *> Predecessors;
std::vector<MachineBasicBlock *> Successors;
/// LiveIns - Keep track of the physical registers that are livein of
/// the basicblock.
std::vector<unsigned> LiveIns;
/// Alignment - Alignment of the basic block. Zero if the basic block does
/// not need to be aligned.
unsigned Alignment;
/// IsLandingPad - Indicate that this basic block is entered via an
/// exception handler.
bool IsLandingPad;
// Intrusive list support
MachineBasicBlock() {}
explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
~MachineBasicBlock();
// MachineBasicBlocks are allocated and owned by MachineFunction.
friend class MachineFunction;
public:
/// getBasicBlock - Return the LLVM basic block that this instance
/// corresponded to originally.
///
const BasicBlock *getBasicBlock() const { return BB; }
/// getParent - Return the MachineFunction containing this basic block.
///
const MachineFunction *getParent() const { return xParent; }
MachineFunction *getParent() { return xParent; }
typedef Instructions::iterator iterator;
typedef Instructions::const_iterator const_iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
typedef std::reverse_iterator<iterator> reverse_iterator;
unsigned size() const { return (unsigned)Insts.size(); }
bool empty() const { return Insts.empty(); }
MachineInstr& front() { return Insts.front(); }
MachineInstr& back() { return Insts.back(); }
const MachineInstr& front() const { return Insts.front(); }
const MachineInstr& back() const { return Insts.back(); }
iterator begin() { return Insts.begin(); }
const_iterator begin() const { return Insts.begin(); }
iterator end() { return Insts.end(); }
const_iterator end() const { return Insts.end(); }
reverse_iterator rbegin() { return Insts.rbegin(); }
const_reverse_iterator rbegin() const { return Insts.rbegin(); }
reverse_iterator rend () { return Insts.rend(); }
const_reverse_iterator rend () const { return Insts.rend(); }
// Machine-CFG iterators
typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
typedef std::vector<MachineBasicBlock *>::reverse_iterator
pred_reverse_iterator;
typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
const_pred_reverse_iterator;
typedef std::vector<MachineBasicBlock *>::reverse_iterator
succ_reverse_iterator;
typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
const_succ_reverse_iterator;
pred_iterator pred_begin() { return Predecessors.begin(); }
const_pred_iterator pred_begin() const { return Predecessors.begin(); }
pred_iterator pred_end() { return Predecessors.end(); }
const_pred_iterator pred_end() const { return Predecessors.end(); }
pred_reverse_iterator pred_rbegin()
{ return Predecessors.rbegin();}
const_pred_reverse_iterator pred_rbegin() const
{ return Predecessors.rbegin();}
pred_reverse_iterator pred_rend()
{ return Predecessors.rend(); }
const_pred_reverse_iterator pred_rend() const
{ return Predecessors.rend(); }
unsigned pred_size() const {
return (unsigned)Predecessors.size();
}
bool pred_empty() const { return Predecessors.empty(); }
succ_iterator succ_begin() { return Successors.begin(); }
const_succ_iterator succ_begin() const { return Successors.begin(); }
succ_iterator succ_end() { return Successors.end(); }
const_succ_iterator succ_end() const { return Successors.end(); }
succ_reverse_iterator succ_rbegin()
{ return Successors.rbegin(); }
const_succ_reverse_iterator succ_rbegin() const
{ return Successors.rbegin(); }
succ_reverse_iterator succ_rend()
{ return Successors.rend(); }
const_succ_reverse_iterator succ_rend() const
{ return Successors.rend(); }
unsigned succ_size() const {
return (unsigned)Successors.size();
}
bool succ_empty() const { return Successors.empty(); }
// LiveIn management methods.
/// addLiveIn - Add the specified register as a live in. Note that it
/// is an error to add the same register to the same set more than once.
void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
/// removeLiveIn - Remove the specified register from the live in set.
///
void removeLiveIn(unsigned Reg);
/// isLiveIn - Return true if the specified register is in the live in set.
///
bool isLiveIn(unsigned Reg) const;
// Iteration support for live in sets. These sets are kept in sorted
// order by their register number.
typedef std::vector<unsigned>::iterator livein_iterator;
typedef std::vector<unsigned>::const_iterator const_livein_iterator;
livein_iterator livein_begin() { return LiveIns.begin(); }
const_livein_iterator livein_begin() const { return LiveIns.begin(); }
livein_iterator livein_end() { return LiveIns.end(); }
const_livein_iterator livein_end() const { return LiveIns.end(); }
bool livein_empty() const { return LiveIns.empty(); }
/// getAlignment - Return alignment of the basic block.
///
unsigned getAlignment() const { return Alignment; }
/// setAlignment - Set alignment of the basic block.
///
void setAlignment(unsigned Align) { Alignment = Align; }
/// isLandingPad - Returns true if the block is a landing pad. That is
/// this basic block is entered via an exception handler.
bool isLandingPad() const { return IsLandingPad; }
/// setIsLandingPad - Indicates the block is a landing pad. That is
/// this basic block is entered via an exception handler.
void setIsLandingPad() { IsLandingPad = true; }
// Code Layout methods.
/// moveBefore/moveAfter - move 'this' block before or after the specified
/// block. This only moves the block, it does not modify the CFG or adjust
/// potential fall-throughs at the end of the block.
void moveBefore(MachineBasicBlock *NewAfter);
void moveAfter(MachineBasicBlock *NewBefore);
// Machine-CFG mutators
/// addSuccessor - Add succ as a successor of this MachineBasicBlock.
/// The Predecessors list of succ is automatically updated.
///
void addSuccessor(MachineBasicBlock *succ);
/// removeSuccessor - Remove successor from the successors list of this
/// MachineBasicBlock. The Predecessors list of succ is automatically updated.
///
void removeSuccessor(MachineBasicBlock *succ);
/// removeSuccessor - Remove specified successor from the successors list of
/// this MachineBasicBlock. The Predecessors list of succ is automatically
/// updated. Return the iterator to the element after the one removed.
///
succ_iterator removeSuccessor(succ_iterator I);
/// transferSuccessors - Transfers all the successors from MBB to this
/// machine basic block (i.e., copies all the successors fromMBB and
/// remove all the successors fromBB).
void transferSuccessors(MachineBasicBlock *fromMBB);
/// isSuccessor - Return true if the specified MBB is a successor of this
/// block.
bool isSuccessor(const MachineBasicBlock *MBB) const;
/// isLayoutSuccessor - Return true if the specified MBB will be emitted
/// immediately after this block, such that if this block exits by
/// falling through, control will transfer to the specified MBB. Note
/// that MBB need not be a successor at all, for example if this block
/// ends with an unconditional branch to some other block.
bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
/// getFirstTerminator - returns an iterator to the first terminator
/// instruction of this basic block. If a terminator does not exist,
/// it returns end()
iterator getFirstTerminator();
/// isOnlyReachableViaFallthough - Return true if this basic block has
/// exactly one predecessor and the control transfer mechanism between
/// the predecessor and this block is a fall-through.
bool isOnlyReachableByFallthrough() const;
void pop_front() { Insts.pop_front(); }
void pop_back() { Insts.pop_back(); }
void push_back(MachineInstr *MI) { Insts.push_back(MI); }
template<typename IT>
void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
// erase - Remove the specified element or range from the instruction list.
// These functions delete any instructions removed.
//
iterator erase(iterator I) { return Insts.erase(I); }
iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); }
void clear() { Insts.clear(); }
/// splice - Take an instruction from MBB 'Other' at the position From,
/// and insert it into this MBB right before 'where'.
void splice(iterator where, MachineBasicBlock *Other, iterator From) {
Insts.splice(where, Other->Insts, From);
}
/// splice - Take a block of instructions from MBB 'Other' in the range [From,
/// To), and insert them into this MBB right before 'where'.
void splice(iterator where, MachineBasicBlock *Other, iterator From,
iterator To) {
Insts.splice(where, Other->Insts, From, To);
}
/// removeFromParent - This method unlinks 'this' from the containing
/// function, and returns it, but does not delete it.
MachineBasicBlock *removeFromParent();
/// eraseFromParent - This method unlinks 'this' from the containing
/// function and deletes it.
void eraseFromParent();
/// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
/// 'Old', change the code and CFG so that it branches to 'New' instead.
void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
/// the CFG to be inserted. If we have proven that MBB can only branch to
/// DestA and DestB, remove any other MBB successors from the CFG. DestA and
/// DestB can be null. Besides DestA and DestB, retain other edges leading
/// to LandingPads (currently there can be only one; we don't check or require
/// that here). Note it is possible that DestA and/or DestB are LandingPads.
bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
MachineBasicBlock *DestB,
bool isCond);
// Debugging methods.
void dump() const;
void print(std::ostream &OS) const;
void print(std::ostream *OS) const { if (OS) print(*OS); }
/// getNumber - MachineBasicBlocks are uniquely numbered at the function
/// level, unless they're not in a MachineFunction yet, in which case this
/// will return -1.
///
int getNumber() const { return Number; }
void setNumber(int N) { Number = N; }
private: // Methods used to maintain doubly linked list of blocks...
friend struct ilist_traits<MachineBasicBlock>;
// Machine-CFG mutators
/// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
/// Don't do this unless you know what you're doing, because it doesn't
/// update pred's successors list. Use pred->addSuccessor instead.
///
void addPredecessor(MachineBasicBlock *pred);
/// removePredecessor - Remove pred as a predecessor of this
/// MachineBasicBlock. Don't do this unless you know what you're
/// doing, because it doesn't update pred's successors list. Use
/// pred->removeSuccessor instead.
///
void removePredecessor(MachineBasicBlock *pred);
};
std::ostream& operator<<(std::ostream &OS, const MachineBasicBlock &MBB);
//===--------------------------------------------------------------------===//
// GraphTraits specializations for machine basic block graphs (machine-CFGs)
//===--------------------------------------------------------------------===//
// Provide specializations of GraphTraits to be able to treat a
// MachineFunction as a graph of MachineBasicBlocks...
//
template <> struct GraphTraits<MachineBasicBlock *> {
typedef MachineBasicBlock NodeType;
typedef MachineBasicBlock::succ_iterator ChildIteratorType;
static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->succ_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->succ_end();
}
};
template <> struct GraphTraits<const MachineBasicBlock *> {
typedef const MachineBasicBlock NodeType;
typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
static inline ChildIteratorType child_begin(NodeType *N) {
return N->succ_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->succ_end();
}
};
// Provide specializations of GraphTraits to be able to treat a
// MachineFunction as a graph of MachineBasicBlocks... and to walk it
// in inverse order. Inverse order for a function is considered
// to be when traversing the predecessor edges of a MBB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
typedef MachineBasicBlock NodeType;
typedef MachineBasicBlock::pred_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
return G.Graph;
}
static inline ChildIteratorType child_begin(NodeType *N) {
return N->pred_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->pred_end();
}
};
template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
typedef const MachineBasicBlock NodeType;
typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
return G.Graph;
}
static inline ChildIteratorType child_begin(NodeType *N) {
return N->pred_begin();
}
static inline ChildIteratorType child_end(NodeType *N) {
return N->pred_end();
}
};
} // End llvm namespace
#endif