This looks dangerous, but isn't because the sentinel is accessed in special way only,
namely the Next and Prev fields of it, and these are guaranteed to exist.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65626
91177308-0d34-0410-b5e6-
96231b3b80d8
template<typename NodeTy>
struct ilist_nextprev_traits;
+template<typename NodeTy>
+struct ilist_traits;
+
/// ilist_node - Base class that provides next/prev services for nodes
/// that use ilist_nextprev_traits or ilist_default_traits.
///
void setNext(NodeTy *N) { Next = N; }
protected:
ilist_node() : Prev(0), Next(0) {}
+ friend struct ilist_traits<NodeTy>;
};
} // End llvm namespace
template<> struct ilist_traits<Instruction>
: 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; }
+ Instruction *createSentinel() const {
+ return const_cast<Instruction*>(static_cast<const Instruction*>(&Sentinel));
+ }
+ static void destroySentinel(Instruction *I) { }
static iplist<Instruction> &getList(BasicBlock *BB);
static ValueSymbolTable *getSymTab(BasicBlock *ItemParent);
static int getListOffset();
+private:
+ ilist_node<Instruction> Sentinel;
};
/// This represents a single basic block in LLVM. A basic block is simply a
/// @brief LLVM Basic Block Representation
class BasicBlock : public Value, // Basic blocks are data objects also
public ilist_node<BasicBlock> {
+
public:
typedef iplist<Instruction> InstListType;
-private :
+private:
InstListType InstList;
Function *Parent;
return 0;
}
-
-namespace {
- /// DummyInst - An instance of this class is used to mark the end of the
- /// instruction list. This is not a real instruction.
- struct VISIBILITY_HIDDEN DummyInst : public Instruction {
- // allocate space for exactly zero operands
- void *operator new(size_t s) {
- return User::operator new(s, 0);
- }
- DummyInst() : Instruction(Type::VoidTy, OtherOpsEnd, 0, 0) {
- // This should not be garbage monitored.
- LeakDetector::removeGarbageObject(this);
- }
-
- Instruction *clone() const {
- assert(0 && "Cannot clone EOL");abort();
- return 0;
- }
- const char *getOpcodeName() const { return "*end-of-list-inst*"; }
-
- // Methods for support type inquiry through isa, cast, and dyn_cast...
- static inline bool classof(const DummyInst *) { return true; }
- static inline bool classof(const Instruction *I) {
- return I->getOpcode() == OtherOpsEnd;
- }
- static inline bool classof(const Value *V) {
- return isa<Instruction>(V) && classof(cast<Instruction>(V));
- }
- };
-}
-
-Instruction *ilist_traits<Instruction>::createSentinel() {
- return new DummyInst();
-}
iplist<Instruction> &ilist_traits<Instruction>::getList(BasicBlock *BB) {
return BB->getInstList();
}