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https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@697 91177308-0d34-0410-b5e6-96231b3b80d8
323 lines
12 KiB
C++
323 lines
12 KiB
C++
//===-- llvm/BasicBlock.h - Represent a basic block in the VM ----*- C++ -*--=//
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//
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// This file contains the declaration of the BasicBlock class, which represents
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// a single basic block in the VM.
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//
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// Note that basic blocks themselves are Def's, because they are referenced
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// by instructions like branches and can go in switch tables and stuff...
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//
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// This may see wierd at first, but it's really pretty cool. :)
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//
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//===----------------------------------------------------------------------===//
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//
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// Note that well formed basic blocks are formed of a list of instructions
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// followed by a single TerminatorInst instruction. TerminatorInst's may not
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// occur in the middle of basic blocks, and must terminate the blocks.
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//
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// This code allows malformed basic blocks to occur, because it may be useful
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// in the intermediate stage of analysis or modification of a program.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_BASICBLOCK_H
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#define LLVM_BASICBLOCK_H
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#include "llvm/Value.h"
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#include "llvm/ValueHolder.h"
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#include "llvm/Support/GraphTraits.h"
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#include "llvm/InstrTypes.h"
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#include <iterator>
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class Instruction;
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class Method;
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class TerminatorInst;
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class MachineCodeForBasicBlock;
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class BasicBlock : public Value { // Basic blocks are data objects also
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template <class _Ptr, class _USE_iterator> class PredIterator;
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template <class _Term, class _BB> class SuccIterator;
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public:
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typedef ValueHolder<Instruction, BasicBlock, Method> InstListType;
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private :
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InstListType InstList;
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MachineCodeForBasicBlock* machineInstrVec;
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friend class ValueHolder<BasicBlock,Method,Method>;
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void setParent(Method *parent);
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public:
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// Instruction iterators...
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typedef InstListType::iterator iterator;
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typedef InstListType::const_iterator const_iterator;
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typedef reverse_iterator<const_iterator> const_reverse_iterator;
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typedef reverse_iterator<iterator> reverse_iterator;
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// Predecessor and successor iterators...
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typedef PredIterator<BasicBlock, Value::use_iterator> pred_iterator;
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typedef PredIterator<const BasicBlock,
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Value::use_const_iterator> pred_const_iterator;
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typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
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typedef SuccIterator<const TerminatorInst*,
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const BasicBlock> succ_const_iterator;
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// Ctor, dtor
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BasicBlock(const string &Name = "", Method *Parent = 0);
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~BasicBlock();
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// Specialize setName to take care of symbol table majik
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virtual void setName(const string &name, SymbolTable *ST = 0);
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// getParent - Return the enclosing method, or null if none
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const Method *getParent() const { return InstList.getParent(); }
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Method *getParent() { return InstList.getParent(); }
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// getTerminator() - If this is a well formed basic block, then this returns
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// a pointer to the terminator instruction. If it is not, then you get a null
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// pointer back.
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//
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TerminatorInst *getTerminator();
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const TerminatorInst *const getTerminator() const;
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// Machine code accessor...
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inline MachineCodeForBasicBlock& getMachineInstrVec() const {
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return *machineInstrVec;
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}
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//===--------------------------------------------------------------------===//
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// Instruction iterator methods
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//
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inline iterator begin() { return InstList.begin(); }
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inline const_iterator begin() const { return InstList.begin(); }
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inline iterator end () { return InstList.end(); }
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inline const_iterator end () const { return InstList.end(); }
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inline reverse_iterator rbegin() { return InstList.rbegin(); }
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inline const_reverse_iterator rbegin() const { return InstList.rbegin(); }
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inline reverse_iterator rend () { return InstList.rend(); }
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inline const_reverse_iterator rend () const { return InstList.rend(); }
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inline unsigned size() const { return InstList.size(); }
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inline bool empty() const { return InstList.empty(); }
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inline const Instruction *front() const { return InstList.front(); }
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inline Instruction *front() { return InstList.front(); }
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inline const Instruction *back() const { return InstList.back(); }
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inline Instruction *back() { return InstList.back(); }
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// getInstList() - Return the underlying instruction list container. You need
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// to access it directly if you want to modify it currently.
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//
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const InstListType &getInstList() const { return InstList; }
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InstListType &getInstList() { return InstList; }
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// Methods for support type inquiry through isa, cast, and dyn_cast:
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static inline bool classof(const BasicBlock *BB) { return true; }
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static inline bool classof(const Value *V) {
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return V->getValueType() == Value::BasicBlockVal;
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}
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// hasConstantPoolReferences() - This predicate is true if there is a
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// reference to this basic block in the constant pool for this method. For
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// example, if a block is reached through a switch table, that table resides
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// in the constant pool, and the basic block is reference from it.
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//
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bool hasConstantPoolReferences() const;
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// dropAllReferences() - This function causes all the subinstructions to "let
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// go" of all references that they are maintaining. This allows one to
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// 'delete' a whole class at a time, even though there may be circular
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// references... first all references are dropped, and all use counts go to
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// zero. Then everything is delete'd for real. Note that no operations are
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// valid on an object that has "dropped all references", except operator
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// delete.
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//
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void dropAllReferences();
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// removePredecessor - This method is used to notify a BasicBlock that the
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// specified Predecessor of the block is no longer able to reach it. This is
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// actually not used to update the Predecessor list, but is actually used to
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// update the PHI nodes that reside in the block. Note that this should be
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// called while the predecessor still refers to this block.
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//
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void removePredecessor(BasicBlock *Pred);
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// splitBasicBlock - This splits a basic block into two at the specified
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// instruction. Note that all instructions BEFORE the specified iterator stay
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// as part of the original basic block, an unconditional branch is added to
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// the new BB, and the rest of the instructions in the BB are moved to the new
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// BB, including the old terminator. The newly formed BasicBlock is returned.
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// This function invalidates the specified iterator.
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//
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// Note that this only works on well formed basic blocks (must have a
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// terminator), and 'I' must not be the end of instruction list (which would
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// cause a degenerate basic block to be formed, having a terminator inside of
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// the basic block).
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//
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BasicBlock *splitBasicBlock(iterator I);
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//===--------------------------------------------------------------------===//
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// Predecessor and Successor Iterators
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//
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template <class _Ptr, class _USE_iterator> // Predecessor Iterator
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class PredIterator : public std::bidirectional_iterator<_Ptr, ptrdiff_t> {
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_Ptr *BB;
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_USE_iterator It;
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public:
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typedef PredIterator<_Ptr,_USE_iterator> _Self;
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inline void advancePastConstPool() {
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// TODO: This is bad
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// Loop to ignore constant pool references
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while (It != BB->use_end() && !isa<TerminatorInst>(*It))
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++It;
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}
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inline PredIterator(_Ptr *bb) : BB(bb), It(bb->use_begin()) {
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advancePastConstPool();
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}
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inline PredIterator(_Ptr *bb, bool) : BB(bb), It(bb->use_end()) {}
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inline bool operator==(const _Self& x) const { return It == x.It; }
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inline bool operator!=(const _Self& x) const { return !operator==(x); }
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inline pointer operator*() const {
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return cast<Instruction>(*It)->getParent();
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}
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inline pointer *operator->() const { return &(operator*()); }
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inline _Self& operator++() { // Preincrement
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++It; advancePastConstPool();
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return *this;
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}
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inline _Self operator++(int) { // Postincrement
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_Self tmp = *this; ++*this; return tmp;
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}
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inline _Self& operator--() { --It; return *this; } // Predecrement
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inline _Self operator--(int) { // Postdecrement
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_Self tmp = *this; --*this; return tmp;
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}
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};
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inline pred_iterator pred_begin() { return pred_iterator(this); }
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inline pred_const_iterator pred_begin() const {
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return pred_const_iterator(this);
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}
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inline pred_iterator pred_end() { return pred_iterator(this, true); }
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inline pred_const_iterator pred_end() const {
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return pred_const_iterator(this, true);
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}
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template <class _Term, class _BB> // Successor Iterator
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class SuccIterator : public std::bidirectional_iterator<_BB, ptrdiff_t> {
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const _Term Term;
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unsigned idx;
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public:
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typedef SuccIterator<_Term, _BB> _Self;
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// TODO: This can be random access iterator, need operator+ and stuff tho
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inline SuccIterator(_Term T) : Term(T), idx(0) { // begin iterator
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assert(T && "getTerminator returned null!");
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}
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inline SuccIterator(_Term T, bool) // end iterator
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: Term(T), idx(Term->getNumSuccessors()) {
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assert(T && "getTerminator returned null!");
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}
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inline bool operator==(const _Self& x) const { return idx == x.idx; }
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inline bool operator!=(const _Self& x) const { return !operator==(x); }
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inline pointer operator*() const { return Term->getSuccessor(idx); }
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inline pointer operator->() const { return operator*(); }
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inline _Self& operator++() { ++idx; return *this; } // Preincrement
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inline _Self operator++(int) { // Postincrement
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_Self tmp = *this; ++*this; return tmp;
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}
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inline _Self& operator--() { --idx; return *this; } // Predecrement
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inline _Self operator--(int) { // Postdecrement
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_Self tmp = *this; --*this; return tmp;
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}
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};
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inline succ_iterator succ_begin() { return succ_iterator(getTerminator()); }
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inline succ_const_iterator succ_begin() const {
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return succ_const_iterator(getTerminator());
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}
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inline succ_iterator succ_end() {return succ_iterator(getTerminator(), true);}
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inline succ_const_iterator succ_end() const {
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return succ_const_iterator(getTerminator(), true);
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}
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};
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//===--------------------------------------------------------------------===//
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// GraphTraits specializations for basic block graphs (CFGs)
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//===--------------------------------------------------------------------===//
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// Provide specializations of GraphTraits to be able to treat a method as a
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// graph of basic blocks...
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template <> struct GraphTraits<BasicBlock*> {
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typedef BasicBlock NodeType;
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typedef BasicBlock::succ_iterator ChildIteratorType;
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static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->succ_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->succ_end();
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}
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};
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template <> struct GraphTraits<const BasicBlock*> {
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typedef const BasicBlock NodeType;
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typedef BasicBlock::succ_const_iterator ChildIteratorType;
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static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->succ_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->succ_end();
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}
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};
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// Provide specializations of GraphTraits to be able to treat a method as a
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// graph of basic blocks... and to walk it in inverse order. Inverse order for
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// a method is considered to be when traversing the predecessor edges of a BB
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// instead of the successor edges.
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//
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template <> struct GraphTraits<Inverse<BasicBlock*> > {
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typedef BasicBlock NodeType;
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typedef BasicBlock::pred_iterator ChildIteratorType;
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static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->pred_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->pred_end();
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}
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};
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template <> struct GraphTraits<Inverse<const BasicBlock*> > {
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typedef const BasicBlock NodeType;
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typedef BasicBlock::pred_const_iterator ChildIteratorType;
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static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
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return G.Graph;
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}
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->pred_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->pred_end();
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}
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};
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#endif
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