//===----------------------------------------------------------------------===//
//
//
-// This file contains the declaration of the BasicBlock class, which represents
-// a single basic block in the VM.
-//
-// Note that basic blocks themselves are Value's, because they are referenced
-// by instructions like branches and can go in switch tables and stuff...
-//
-///===---------------------------------------------------------------------===//
-//
-// Note that well formed basic blocks are formed of a list of instructions
-// followed by a single TerminatorInst instruction. TerminatorInst's may not
-// occur in the middle of basic blocks, and must terminate the blocks.
-//
-// This code allows malformed basic blocks to occur, because it may be useful
-// in the intermediate stage modification to a program.
-//
+// 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/Support/DataTypes.h"
namespace llvm {
template <class Ptr, class USE_iterator> class PredIterator;
template<> struct ilist_traits<Instruction>
- : public SymbolTableListTraits<Instruction, BasicBlock, Function> {
+ : public SymbolTableListTraits<Instruction, BasicBlock> {
// 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);
+ static ValueSymbolTable *getSymTab(BasicBlock *ItemParent);
+ static int getListOffset();
};
+/// This represents a single basic block in LLVM. A basic block is simply a
+/// container of instructions that execute sequentially. Basic blocks are Values
+/// because they are referenced by instructions such as branches and switch
+/// tables. The type of a BasicBlock is "Type::LabelTy" because the basic block
+/// represents a label to which a branch can jump.
+///
+/// A well formed basic block is formed of a list of non-terminating
+/// instructions followed by a single TerminatorInst instruction.
+/// TerminatorInst's may not occur in the middle of basic blocks, and must
+/// terminate the blocks. The BasicBlock class allows malformed basic blocks to
+/// occur because it may be useful in the intermediate stage of constructing or
+/// 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
public:
typedef iplist<Instruction> InstListType;
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
/// is automatically inserted at either the end of the function (if
/// InsertBefore is null), or before the specified basic block.
///
- BasicBlock(const std::string &Name = "", Function *Parent = 0,
- BasicBlock *InsertBefore = 0);
+ explicit BasicBlock(const std::string &Name = "", Function *Parent = 0,
+ BasicBlock *InsertBefore = 0);
~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());}
+
/// 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
+ /// basic block, they should be added before the returned value, not before
+ /// the first instruction, which might be PHI.
+ /// Returns 0 is there's no non-PHI instruction.
+ Instruction* getFirstNonPHI();
+
/// removeFromParent - This method unlinks 'this' from the containing
/// function, but does not delete it.
///
/// and deletes it.
///
void eraseFromParent();
+
+ /// moveBefore - Unlink this basic block from its current function and
+ /// insert it into the function that MovePos lives in, right before MovePos.
+ void moveBefore(BasicBlock *MovePos);
+
+ /// moveAfter - Unlink this basic block from its current function and
+ /// insert it into the function that MovePos lives in, right after MovePos.
+ void moveAfter(BasicBlock *MovePos);
+
/// getSinglePredecessor - If this basic block has a single predecessor block,
/// return the block, otherwise return a null pointer.
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;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
- static inline bool classof(const BasicBlock *BB) { return true; }
+ 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
/// splitBasicBlock - This splits a basic block into two at the specified
/// instruction. Note that all instructions BEFORE the specified iterator
/// stay as part of the original basic block, an unconditional branch is added
- /// to the original BB, and the rest of the instructions in the BB are moved
+ /// to the original BB, and the rest of the instructions in the BB are moved
/// to the new BB, including the old terminator. The newly formed BasicBlock
/// is returned. This function invalidates the specified iterator.
///
/// the basic block).
///
BasicBlock *splitBasicBlock(iterator I, const std::string &BBName = "");
+
+
+ static unsigned getInstListOffset() {
+ BasicBlock *Obj = 0;
+ return unsigned(reinterpret_cast<uintptr_t>(&Obj->InstList));
+ }
+
+private:
+ // getNext/Prev - Return the next or previous basic block in the list. Access
+ // these with Function::iterator.
+ BasicBlock *getNext() { return Next; }
+ const BasicBlock *getNext() const { return Next; }
+ BasicBlock *getPrev() { return Prev; }
+ const BasicBlock *getPrev() const { return Prev; }
};
+inline int
+ilist_traits<Instruction>::getListOffset() {
+ return BasicBlock::getInstListOffset();
+}
+
} // End llvm namespace
#endif
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