//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-//
// This file contains the declaration of the BasicBlock class.
+//
//===----------------------------------------------------------------------===//
#ifndef LLVM_BASICBLOCK_H
#include "llvm/Instruction.h"
#include "llvm/SymbolTableListTraits.h"
-#include "llvm/ADT/ilist"
+#include "llvm/ADT/ilist.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/System/DataTypes.h"
namespace llvm {
class TerminatorInst;
-template <class Term, class BB> class SuccIterator; // Successor Iterator
-template <class Ptr, class USE_iterator> class PredIterator;
+class LLVMContext;
+class BlockAddress;
template<> struct ilist_traits<Instruction>
- : public SymbolTableListTraits<Instruction, BasicBlock, Function> {
- // createSentinel is used to create a node that marks the end of the list...
- static Instruction *createSentinel();
- static void destroySentinel(Instruction *I) { delete I; }
- static iplist<Instruction> &getList(BasicBlock *BB);
+ : public SymbolTableListTraits<Instruction, BasicBlock> {
+ // createSentinel is used to get hold of a node that marks the end of
+ // the list...
+ // The sentinel is relative to this instance, so we use a non-static
+ // method.
+ Instruction *createSentinel() const {
+ // since i(p)lists always publicly derive from the corresponding
+ // traits, placing a data member in this class will augment i(p)list.
+ // But since the NodeTy is expected to publicly derive from
+ // ilist_node<NodeTy>, there is a legal viable downcast from it
+ // to NodeTy. We use this trick to superpose i(p)list with a "ghostly"
+ // NodeTy, which becomes the sentinel. Dereferencing the sentinel is
+ // forbidden (save the ilist_node<NodeTy>) so no one will ever notice
+ // the superposition.
+ return static_cast<Instruction*>(&Sentinel);
+ }
+ static void destroySentinel(Instruction*) {}
+
+ Instruction *provideInitialHead() const { return createSentinel(); }
+ Instruction *ensureHead(Instruction*) const { return createSentinel(); }
+ static void noteHead(Instruction*, Instruction*) {}
+private:
+ mutable ilist_half_node<Instruction> Sentinel;
};
/// This represents a single basic block in LLVM. A basic block is simply a
/// modifying a program. However, the verifier will ensure that basic blocks
/// are "well formed".
/// @brief LLVM Basic Block Representation
-class BasicBlock : public Value { // Basic blocks are data objects also
+class BasicBlock : public Value, // Basic blocks are data objects also
+ public ilist_node<BasicBlock> {
+ friend class BlockAddress;
public:
typedef iplist<Instruction> InstListType;
-private :
+private:
InstListType InstList;
- BasicBlock *Prev, *Next; // Next and Prev links for our intrusive linked list
+ Function *Parent;
void setParent(Function *parent);
- void setNext(BasicBlock *N) { Next = N; }
- void setPrev(BasicBlock *N) { Prev = N; }
- friend class SymbolTableListTraits<BasicBlock, Function, Function>;
+ friend class SymbolTableListTraits<BasicBlock, Function>;
BasicBlock(const BasicBlock &); // Do not implement
void operator=(const BasicBlock &); // Do not implement
+ /// BasicBlock ctor - If the function parameter is specified, the basic block
+ /// is automatically inserted at either the end of the function (if
+ /// InsertBefore is null), or before the specified basic block.
+ ///
+ explicit BasicBlock(LLVMContext &C, const Twine &Name = "",
+ Function *Parent = 0, BasicBlock *InsertBefore = 0);
public:
+ /// getContext - Get the context in which this basic block lives.
+ LLVMContext &getContext() const;
+
/// Instruction iterators...
typedef InstListType::iterator iterator;
typedef InstListType::const_iterator const_iterator;
- /// BasicBlock ctor - If the function parameter is specified, the basic block
- /// is automatically inserted at either the end of the function (if
- /// InsertBefore is null), or before the specified basic block.
- ///
- explicit BasicBlock(const std::string &Name = "", Function *Parent = 0,
- BasicBlock *InsertBefore = 0);
+ /// Create - Creates a new BasicBlock. If the Parent parameter is specified,
+ /// the basic block is automatically inserted at either the end of the
+ /// function (if InsertBefore is 0), or before the specified basic block.
+ static BasicBlock *Create(LLVMContext &Context, const Twine &Name = "",
+ Function *Parent = 0,BasicBlock *InsertBefore = 0) {
+ return new BasicBlock(Context, Name, Parent, InsertBefore);
+ }
~BasicBlock();
/// getParent - Return the enclosing method, or null if none
///
- const Function *getParent() const { return InstList.getParent(); }
- Function *getParent() { return InstList.getParent(); }
-
- // getNext/Prev - Return the next or previous basic block in the list.
- BasicBlock *getNext() { return Next; }
- const BasicBlock *getNext() const { return Next; }
- BasicBlock *getPrev() { return Prev; }
- const BasicBlock *getPrev() const { return Prev; }
+ const Function *getParent() const { return Parent; }
+ Function *getParent() { return Parent; }
/// use_back - Specialize the methods defined in Value, as we know that an
- /// BasicBlock can only be used by Instructions (specifically PHI and terms).
- Instruction *use_back() { return cast<Instruction>(*use_begin());}
- const Instruction *use_back() const { return cast<Instruction>(*use_begin());}
+ /// BasicBlock can only be used by Users (specifically PHI nodes, terminators,
+ /// and BlockAddress's).
+ User *use_back() { return cast<User>(*use_begin());}
+ const User *use_back() const { return cast<User>(*use_begin());}
/// getTerminator() - If this is a well formed basic block, then this returns
/// a pointer to the terminator instruction. If it is not, then you get a
/// null pointer back.
///
TerminatorInst *getTerminator();
- const TerminatorInst *const getTerminator() const;
+ const TerminatorInst *getTerminator() const;
/// Returns a pointer to the first instructon in this block that is not a
/// PHINode instruction. When adding instruction to the beginning of the
/// the first instruction, which might be PHI.
/// Returns 0 is there's no non-PHI instruction.
Instruction* getFirstNonPHI();
+ const Instruction* getFirstNonPHI() const {
+ return const_cast<BasicBlock*>(this)->getFirstNonPHI();
+ }
/// removeFromParent - This method unlinks 'this' from the containing
/// function, but does not delete it.
return const_cast<BasicBlock*>(this)->getSinglePredecessor();
}
+ /// getUniquePredecessor - If this basic block has a unique predecessor block,
+ /// return the block, otherwise return a null pointer.
+ /// Note that unique predecessor doesn't mean single edge, there can be
+ /// multiple edges from the unique predecessor to this block (for example
+ /// a switch statement with multiple cases having the same destination).
+ BasicBlock *getUniquePredecessor();
+ const BasicBlock *getUniquePredecessor() const {
+ return const_cast<BasicBlock*>(this)->getUniquePredecessor();
+ }
+
//===--------------------------------------------------------------------===//
/// Instruction iterator methods
///
const InstListType &getInstList() const { return InstList; }
InstListType &getInstList() { return InstList; }
- virtual void print(std::ostream &OS) const { print(OS, 0); }
- void print(std::ostream *OS) const { if (OS) print(*OS); }
- void print(std::ostream &OS, AssemblyAnnotationWriter *AAW) const;
+ /// getSublistAccess() - returns pointer to member of instruction list
+ static iplist<Instruction> BasicBlock::*getSublistAccess(Instruction*) {
+ return &BasicBlock::InstList;
+ }
+
+ /// getValueSymbolTable() - returns pointer to symbol table (if any)
+ ValueSymbolTable *getValueSymbolTable();
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const BasicBlock *) { return true; }
static inline bool classof(const Value *V) {
- return V->getValueType() == Value::BasicBlockVal;
+ return V->getValueID() == Value::BasicBlockVal;
}
/// dropAllReferences() - This function causes all the subinstructions to "let
/// cause a degenerate basic block to be formed, having a terminator inside of
/// the basic block).
///
- BasicBlock *splitBasicBlock(iterator I, const std::string &BBName = "");
+ /// Also note that this doesn't preserve any passes. To split blocks while
+ /// keeping loop information consistent, use the SplitBlock utility function.
+ ///
+ BasicBlock *splitBasicBlock(iterator I, const Twine &BBName = "");
+
+ /// hasAddressTaken - returns true if there are any uses of this basic block
+ /// other than direct branches, switches, etc. to it.
+ bool hasAddressTaken() const { return getSubclassDataFromValue() != 0; }
+
+private:
+ /// AdjustBlockAddressRefCount - BasicBlock stores the number of BlockAddress
+ /// objects using it. This is almost always 0, sometimes one, possibly but
+ /// almost never 2, and inconceivably 3 or more.
+ void AdjustBlockAddressRefCount(int Amt) {
+ setValueSubclassData(getSubclassDataFromValue()+Amt);
+ assert((int)(signed char)getSubclassDataFromValue() >= 0 &&
+ "Refcount wrap-around");
+ }
+ // Shadow Value::setValueSubclassData with a private forwarding method so that
+ // any future subclasses cannot accidentally use it.
+ void setValueSubclassData(unsigned short D) {
+ Value::setValueSubclassData(D);
+ }
};
} // End llvm namespace