/// reg_begin/reg_end - Provide iteration support to walk over all definitions
/// and uses of a register within the MachineFunction that corresponds to this
/// MachineRegisterInfo object.
- class reg_iterator;
+ template<bool Uses, bool Defs>
+ class defusechain_iterator;
+
+ /// reg_iterator/reg_begin/reg_end - Walk all defs and uses of the specified
+ /// register.
+ typedef defusechain_iterator<true,true> reg_iterator;
reg_iterator reg_begin(unsigned RegNo) const {
return reg_iterator(getRegUseDefListHead(RegNo));
}
static reg_iterator reg_end() { return reg_iterator(0); }
+
+ /// def_iterator/def_begin/def_end - Walk all defs of the specified register.
+ typedef defusechain_iterator<false,true> def_iterator;
+ def_iterator def_begin(unsigned RegNo) const {
+ return def_iterator(getRegUseDefListHead(RegNo));
+ }
+ static def_iterator def_end() { return def_iterator(0); }
+
+ /// use_iterator/use_begin/use_end - Walk all uses of the specified register.
+ typedef defusechain_iterator<true,false> use_iterator;
+ use_iterator use_begin(unsigned RegNo) const {
+ return use_iterator(getRegUseDefListHead(RegNo));
+ }
+ static use_iterator use_end() { return use_iterator(0); }
+
+
+ /// replaceRegWith - Replace all instances of FromReg with ToReg in the
+ /// machine function. This is like llvm-level X->replaceAllUsesWith(Y),
+ /// except that it also changes any definitions of the register as well.
+ void replaceRegWith(unsigned FromReg, unsigned ToReg);
/// getRegUseDefListHead - Return the head pointer for the register use/def
/// list for the specified virtual or physical register.
unsigned createVirtualRegister(const TargetRegisterClass *RegClass) {
assert(RegClass && "Cannot create register without RegClass!");
// Add a reg, but keep track of whether the vector reallocated or not.
- void *ArrayBase = &VRegInfo[0];
+ void *ArrayBase = VRegInfo.empty() ? 0 : &VRegInfo[0];
VRegInfo.push_back(std::make_pair(RegClass, (MachineOperand*)0));
- if (&VRegInfo[0] == ArrayBase)
+ if (&VRegInfo[0] == ArrayBase || VRegInfo.size() == 1)
return getLastVirtReg();
// Otherwise, the vector reallocated, handle this now.
void HandleVRegListReallocation();
public:
- /// reg_iterator - This class provides iterator support for machine
- /// operands in the function that use or define a specific register.
- class reg_iterator : public forward_iterator<MachineOperand, ptrdiff_t> {
- typedef forward_iterator<MachineOperand, ptrdiff_t> super;
-
+ /// defusechain_iterator - This class provides iterator support for machine
+ /// operands in the function that use or define a specific register. If
+ /// ReturnUses is true it returns uses of registers, if ReturnDefs is true it
+ /// returns defs. If neither are true then you are silly and it always
+ /// returns end().
+ template<bool ReturnUses, bool ReturnDefs>
+ class defusechain_iterator
+ : public forward_iterator<MachineInstr, ptrdiff_t> {
MachineOperand *Op;
- reg_iterator(MachineOperand *op) : Op(op) {}
+ defusechain_iterator(MachineOperand *op) : Op(op) {
+ // If the first node isn't one we're interested in, advance to one that
+ // we are interested in.
+ if (op) {
+ if (!ReturnUses && op->isUse() ||
+ !ReturnDefs && op->isDef())
+ ++*this;
+ }
+ }
friend class MachineRegisterInfo;
public:
- typedef super::reference reference;
- typedef super::pointer pointer;
+ typedef forward_iterator<MachineInstr, ptrdiff_t>::reference reference;
+ typedef forward_iterator<MachineInstr, ptrdiff_t>::pointer pointer;
- reg_iterator(const reg_iterator &I) : Op(I.Op) {}
- reg_iterator() : Op(0) {}
+ defusechain_iterator(const defusechain_iterator &I) : Op(I.Op) {}
+ defusechain_iterator() : Op(0) {}
- bool operator==(const reg_iterator &x) const {
+ bool operator==(const defusechain_iterator &x) const {
return Op == x.Op;
}
- bool operator!=(const reg_iterator &x) const {
+ bool operator!=(const defusechain_iterator &x) const {
return !operator==(x);
}
bool atEnd() const { return Op == 0; }
// Iterator traversal: forward iteration only
- reg_iterator &operator++() { // Preincrement
+ defusechain_iterator &operator++() { // Preincrement
assert(Op && "Cannot increment end iterator!");
Op = Op->getNextOperandForReg();
+
+ // If this is an operand we don't care about, skip it.
+ while (Op && (!ReturnUses && Op->isUse() ||
+ !ReturnDefs && Op->isDef()))
+ Op = Op->getNextOperandForReg();
+
return *this;
}
- reg_iterator operator++(int) { // Postincrement
- reg_iterator tmp = *this; ++*this; return tmp;
+ defusechain_iterator operator++(int) { // Postincrement
+ defusechain_iterator tmp = *this; ++*this; return tmp;
}
- // Retrieve a reference to the current operand.
- MachineOperand &operator*() const {
+ MachineOperand &getOperand() const {
assert(Op && "Cannot dereference end iterator!");
return *Op;
}
- MachineOperand *operator->() const { return Op; }
+ /// getOperandNo - Return the operand # of this MachineOperand in its
+ /// MachineInstr.
+ unsigned getOperandNo() const {
+ assert(Op && "Cannot dereference end iterator!");
+ return Op - &Op->getParent()->getOperand(0);
+ }
+
+ // Retrieve a reference to the current operand.
+ MachineInstr &operator*() const {
+ assert(Op && "Cannot dereference end iterator!");
+ return *Op->getParent();
+ }
+
+ MachineInstr *operator->() const {
+ assert(Op && "Cannot dereference end iterator!");
+ return Op->getParent();
+ }
};
};
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