llvm-6502/include/llvm/IR/CFG.h
Chandler Carruth 36b699f2b1 [C++11] Add range based accessors for the Use-Def chain of a Value.
This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203364 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-09 03:16:01 +00:00

384 lines
12 KiB
C++

//===- CFG.h - Process LLVM structures as graphs ----------------*- 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 specializations of GraphTraits that allow Function and
// BasicBlock graphs to be treated as proper graphs for generic algorithms.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_CFG_H
#define LLVM_IR_CFG_H
#include "llvm/ADT/GraphTraits.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstrTypes.h"
namespace llvm {
//===----------------------------------------------------------------------===//
// BasicBlock pred_iterator definition
//===----------------------------------------------------------------------===//
template <class Ptr, class USE_iterator> // Predecessor Iterator
class PredIterator : public std::iterator<std::forward_iterator_tag,
Ptr, ptrdiff_t, Ptr*, Ptr*> {
typedef std::iterator<std::forward_iterator_tag, Ptr, ptrdiff_t, Ptr*,
Ptr*> super;
typedef PredIterator<Ptr, USE_iterator> Self;
USE_iterator It;
inline void advancePastNonTerminators() {
// Loop to ignore non-terminator uses (for example BlockAddresses).
while (!It.atEnd() && !isa<TerminatorInst>(*It))
++It;
}
public:
typedef typename super::pointer pointer;
typedef typename super::reference reference;
PredIterator() {}
explicit inline PredIterator(Ptr *bb) : It(bb->user_begin()) {
advancePastNonTerminators();
}
inline PredIterator(Ptr *bb, bool) : It(bb->user_end()) {}
inline bool operator==(const Self& x) const { return It == x.It; }
inline bool operator!=(const Self& x) const { return !operator==(x); }
inline reference operator*() const {
assert(!It.atEnd() && "pred_iterator out of range!");
return cast<TerminatorInst>(*It)->getParent();
}
inline pointer *operator->() const { return &operator*(); }
inline Self& operator++() { // Preincrement
assert(!It.atEnd() && "pred_iterator out of range!");
++It; advancePastNonTerminators();
return *this;
}
inline Self operator++(int) { // Postincrement
Self tmp = *this; ++*this; return tmp;
}
/// getOperandNo - Return the operand number in the predecessor's
/// terminator of the successor.
unsigned getOperandNo() const {
return It.getOperandNo();
}
/// getUse - Return the operand Use in the predecessor's terminator
/// of the successor.
Use &getUse() const {
return It.getUse();
}
};
typedef PredIterator<BasicBlock, Value::user_iterator> pred_iterator;
typedef PredIterator<const BasicBlock,
Value::const_user_iterator> const_pred_iterator;
inline pred_iterator pred_begin(BasicBlock *BB) { return pred_iterator(BB); }
inline const_pred_iterator pred_begin(const BasicBlock *BB) {
return const_pred_iterator(BB);
}
inline pred_iterator pred_end(BasicBlock *BB) { return pred_iterator(BB, true);}
inline const_pred_iterator pred_end(const BasicBlock *BB) {
return const_pred_iterator(BB, true);
}
//===----------------------------------------------------------------------===//
// BasicBlock succ_iterator definition
//===----------------------------------------------------------------------===//
template <class Term_, class BB_> // Successor Iterator
class SuccIterator : public std::iterator<std::random_access_iterator_tag, BB_,
int, BB_ *, BB_ *> {
typedef std::iterator<std::random_access_iterator_tag, BB_, int, BB_ *, BB_ *>
super;
public:
typedef typename super::pointer pointer;
typedef typename super::reference reference;
private:
const Term_ Term;
unsigned idx;
typedef SuccIterator<Term_, BB_> Self;
inline bool index_is_valid(int idx) {
return idx >= 0 && (unsigned) idx < Term->getNumSuccessors();
}
/// \brief Proxy object to allow write access in operator[]
class SuccessorProxy {
Self it;
public:
explicit SuccessorProxy(const Self &it) : it(it) {}
SuccessorProxy &operator=(SuccessorProxy r) {
*this = reference(r);
return *this;
}
SuccessorProxy &operator=(reference r) {
it.Term->setSuccessor(it.idx, r);
return *this;
}
operator reference() const { return *it; }
};
public:
explicit inline SuccIterator(Term_ T) : Term(T), idx(0) {// begin iterator
}
inline SuccIterator(Term_ T, bool) // end iterator
: Term(T) {
if (Term)
idx = Term->getNumSuccessors();
else
// Term == NULL happens, if a basic block is not fully constructed and
// consequently getTerminator() returns NULL. In this case we construct a
// SuccIterator which describes a basic block that has zero successors.
// Defining SuccIterator for incomplete and malformed CFGs is especially
// useful for debugging.
idx = 0;
}
inline const Self &operator=(const Self &I) {
assert(Term == I.Term &&"Cannot assign iterators to two different blocks!");
idx = I.idx;
return *this;
}
/// getSuccessorIndex - This is used to interface between code that wants to
/// operate on terminator instructions directly.
unsigned getSuccessorIndex() const { return idx; }
inline bool operator==(const Self& x) const { return idx == x.idx; }
inline bool operator!=(const Self& x) const { return !operator==(x); }
inline reference operator*() const { return Term->getSuccessor(idx); }
inline pointer operator->() const { return operator*(); }
inline Self& operator++() { ++idx; return *this; } // Preincrement
inline Self operator++(int) { // Postincrement
Self tmp = *this; ++*this; return tmp;
}
inline Self& operator--() { --idx; return *this; } // Predecrement
inline Self operator--(int) { // Postdecrement
Self tmp = *this; --*this; return tmp;
}
inline bool operator<(const Self& x) const {
assert(Term == x.Term && "Cannot compare iterators of different blocks!");
return idx < x.idx;
}
inline bool operator<=(const Self& x) const {
assert(Term == x.Term && "Cannot compare iterators of different blocks!");
return idx <= x.idx;
}
inline bool operator>=(const Self& x) const {
assert(Term == x.Term && "Cannot compare iterators of different blocks!");
return idx >= x.idx;
}
inline bool operator>(const Self& x) const {
assert(Term == x.Term && "Cannot compare iterators of different blocks!");
return idx > x.idx;
}
inline Self& operator+=(int Right) {
unsigned new_idx = idx + Right;
assert(index_is_valid(new_idx) && "Iterator index out of bound");
idx = new_idx;
return *this;
}
inline Self operator+(int Right) const {
Self tmp = *this;
tmp += Right;
return tmp;
}
inline Self& operator-=(int Right) {
return operator+=(-Right);
}
inline Self operator-(int Right) const {
return operator+(-Right);
}
inline int operator-(const Self& x) const {
assert(Term == x.Term && "Cannot work on iterators of different blocks!");
int distance = idx - x.idx;
return distance;
}
inline SuccessorProxy operator[](int offset) {
Self tmp = *this;
tmp += offset;
return SuccessorProxy(tmp);
}
/// Get the source BB of this iterator.
inline BB_ *getSource() {
assert(Term && "Source not available, if basic block was malformed");
return Term->getParent();
}
};
typedef SuccIterator<TerminatorInst*, BasicBlock> succ_iterator;
typedef SuccIterator<const TerminatorInst*,
const BasicBlock> succ_const_iterator;
inline succ_iterator succ_begin(BasicBlock *BB) {
return succ_iterator(BB->getTerminator());
}
inline succ_const_iterator succ_begin(const BasicBlock *BB) {
return succ_const_iterator(BB->getTerminator());
}
inline succ_iterator succ_end(BasicBlock *BB) {
return succ_iterator(BB->getTerminator(), true);
}
inline succ_const_iterator succ_end(const BasicBlock *BB) {
return succ_const_iterator(BB->getTerminator(), true);
}
template <typename T, typename U> struct isPodLike<SuccIterator<T, U> > {
static const bool value = isPodLike<T>::value;
};
//===--------------------------------------------------------------------===//
// GraphTraits specializations for basic block graphs (CFGs)
//===--------------------------------------------------------------------===//
// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks...
template <> struct GraphTraits<BasicBlock*> {
typedef BasicBlock NodeType;
typedef succ_iterator ChildIteratorType;
static NodeType *getEntryNode(BasicBlock *BB) { return BB; }
static inline ChildIteratorType child_begin(NodeType *N) {
return succ_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return succ_end(N);
}
};
template <> struct GraphTraits<const BasicBlock*> {
typedef const BasicBlock NodeType;
typedef succ_const_iterator ChildIteratorType;
static NodeType *getEntryNode(const BasicBlock *BB) { return BB; }
static inline ChildIteratorType child_begin(NodeType *N) {
return succ_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return succ_end(N);
}
};
// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... and to walk it in inverse order. Inverse order for
// a function is considered to be when traversing the predecessor edges of a BB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<BasicBlock*> > {
typedef BasicBlock NodeType;
typedef pred_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<BasicBlock *> G) { return G.Graph; }
static inline ChildIteratorType child_begin(NodeType *N) {
return pred_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return pred_end(N);
}
};
template <> struct GraphTraits<Inverse<const BasicBlock*> > {
typedef const BasicBlock NodeType;
typedef const_pred_iterator ChildIteratorType;
static NodeType *getEntryNode(Inverse<const BasicBlock*> G) {
return G.Graph;
}
static inline ChildIteratorType child_begin(NodeType *N) {
return pred_begin(N);
}
static inline ChildIteratorType child_end(NodeType *N) {
return pred_end(N);
}
};
//===--------------------------------------------------------------------===//
// GraphTraits specializations for function basic block graphs (CFGs)
//===--------------------------------------------------------------------===//
// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... these are the same as the basic block iterators,
// except that the root node is implicitly the first node of the function.
//
template <> struct GraphTraits<Function*> : public GraphTraits<BasicBlock*> {
static NodeType *getEntryNode(Function *F) { return &F->getEntryBlock(); }
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
typedef Function::iterator nodes_iterator;
static nodes_iterator nodes_begin(Function *F) { return F->begin(); }
static nodes_iterator nodes_end (Function *F) { return F->end(); }
static size_t size (Function *F) { return F->size(); }
};
template <> struct GraphTraits<const Function*> :
public GraphTraits<const BasicBlock*> {
static NodeType *getEntryNode(const Function *F) {return &F->getEntryBlock();}
// nodes_iterator/begin/end - Allow iteration over all nodes in the graph
typedef Function::const_iterator nodes_iterator;
static nodes_iterator nodes_begin(const Function *F) { return F->begin(); }
static nodes_iterator nodes_end (const Function *F) { return F->end(); }
static size_t size (const Function *F) { return F->size(); }
};
// Provide specializations of GraphTraits to be able to treat a function as a
// graph of basic blocks... and to walk it in inverse order. Inverse order for
// a function is considered to be when traversing the predecessor edges of a BB
// instead of the successor edges.
//
template <> struct GraphTraits<Inverse<Function*> > :
public GraphTraits<Inverse<BasicBlock*> > {
static NodeType *getEntryNode(Inverse<Function*> G) {
return &G.Graph->getEntryBlock();
}
};
template <> struct GraphTraits<Inverse<const Function*> > :
public GraphTraits<Inverse<const BasicBlock*> > {
static NodeType *getEntryNode(Inverse<const Function *> G) {
return &G.Graph->getEntryBlock();
}
};
} // End llvm namespace
#endif