diff options
Diffstat (limited to 'include/llvm/CodeGen/MachineRegisterInfo.h')
| -rw-r--r-- | include/llvm/CodeGen/MachineRegisterInfo.h | 78 |
1 files changed, 53 insertions, 25 deletions
diff --git a/include/llvm/CodeGen/MachineRegisterInfo.h b/include/llvm/CodeGen/MachineRegisterInfo.h index 42a8aa43d982..4e86363f071a 100644 --- a/include/llvm/CodeGen/MachineRegisterInfo.h +++ b/include/llvm/CodeGen/MachineRegisterInfo.h @@ -77,16 +77,20 @@ class MachineRegisterInfo { return MO->Contents.Reg.Next; } - /// UsedPhysRegs - This is a bit vector that is computed and set by the + /// UsedRegUnits - This is a bit vector that is computed and set by the /// register allocator, and must be kept up to date by passes that run after /// register allocation (though most don't modify this). This is used /// so that the code generator knows which callee save registers to save and /// for other target specific uses. - /// This vector only has bits set for registers explicitly used, not their - /// aliases. - BitVector UsedPhysRegs; + /// This vector has bits set for register units that are modified in the + /// current function. It doesn't include registers clobbered by function + /// calls with register mask operands. + BitVector UsedRegUnits; - /// UsedPhysRegMask - Additional used physregs, but including aliases. + /// UsedPhysRegMask - Additional used physregs including aliases. + /// This bit vector represents all the registers clobbered by function calls. + /// It can model things that UsedRegUnits can't, such as function calls that + /// clobber ymm7 but preserve the low half in xmm7. BitVector UsedPhysRegMask; /// ReservedRegs - This is a bit vector of reserved registers. The target @@ -95,9 +99,6 @@ class MachineRegisterInfo { /// started. BitVector ReservedRegs; - /// AllocatableRegs - From TRI->getAllocatableSet. - mutable BitVector AllocatableRegs; - /// LiveIns/LiveOuts - Keep track of the physical registers that are /// livein/liveout of the function. Live in values are typically arguments in /// registers, live out values are typically return values in registers. @@ -106,8 +107,8 @@ class MachineRegisterInfo { std::vector<std::pair<unsigned, unsigned> > LiveIns; std::vector<unsigned> LiveOuts; - MachineRegisterInfo(const MachineRegisterInfo&); // DO NOT IMPLEMENT - void operator=(const MachineRegisterInfo&); // DO NOT IMPLEMENT + MachineRegisterInfo(const MachineRegisterInfo&) LLVM_DELETED_FUNCTION; + void operator=(const MachineRegisterInfo&) LLVM_DELETED_FUNCTION; public: explicit MachineRegisterInfo(const TargetRegisterInfo &TRI); ~MachineRegisterInfo(); @@ -360,29 +361,27 @@ public: //===--------------------------------------------------------------------===// /// isPhysRegUsed - Return true if the specified register is used in this - /// function. This only works after register allocation. + /// function. Also check for clobbered aliases and registers clobbered by + /// function calls with register mask operands. + /// + /// This only works after register allocation. It is primarily used by + /// PrologEpilogInserter to determine which callee-saved registers need + /// spilling. bool isPhysRegUsed(unsigned Reg) const { - return UsedPhysRegs.test(Reg) || UsedPhysRegMask.test(Reg); - } - - /// isPhysRegOrOverlapUsed - Return true if Reg or any overlapping register - /// is used in this function. - bool isPhysRegOrOverlapUsed(unsigned Reg) const { if (UsedPhysRegMask.test(Reg)) return true; - for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) - if (UsedPhysRegs.test(*AI)) + for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) + if (UsedRegUnits.test(*Units)) return true; return false; } /// setPhysRegUsed - Mark the specified register used in this function. /// This should only be called during and after register allocation. - void setPhysRegUsed(unsigned Reg) { UsedPhysRegs.set(Reg); } - - /// addPhysRegsUsed - Mark the specified registers used in this function. - /// This should only be called during and after register allocation. - void addPhysRegsUsed(const BitVector &Regs) { UsedPhysRegs |= Regs; } + void setPhysRegUsed(unsigned Reg) { + for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) + UsedRegUnits.set(*Units); + } /// addPhysRegsUsedFromRegMask - Mark any registers not in RegMask as used. /// This corresponds to the bit mask attached to register mask operands. @@ -393,8 +392,9 @@ public: /// setPhysRegUnused - Mark the specified register unused in this function. /// This should only be called during and after register allocation. void setPhysRegUnused(unsigned Reg) { - UsedPhysRegs.reset(Reg); UsedPhysRegMask.reset(Reg); + for (MCRegUnitIterator Units(Reg, TRI); Units.isValid(); ++Units) + UsedRegUnits.reset(*Units); } @@ -427,6 +427,34 @@ public: return !reservedRegsFrozen() || ReservedRegs.test(PhysReg); } + /// getReservedRegs - Returns a reference to the frozen set of reserved + /// registers. This method should always be preferred to calling + /// TRI::getReservedRegs() when possible. + const BitVector &getReservedRegs() const { + assert(reservedRegsFrozen() && + "Reserved registers haven't been frozen yet. " + "Use TRI::getReservedRegs()."); + return ReservedRegs; + } + + /// isReserved - Returns true when PhysReg is a reserved register. + /// + /// Reserved registers may belong to an allocatable register class, but the + /// target has explicitly requested that they are not used. + /// + bool isReserved(unsigned PhysReg) const { + return getReservedRegs().test(PhysReg); + } + + /// isAllocatable - Returns true when PhysReg belongs to an allocatable + /// register class and it hasn't been reserved. + /// + /// Allocatable registers may show up in the allocation order of some virtual + /// register, so a register allocator needs to track its liveness and + /// availability. + bool isAllocatable(unsigned PhysReg) const { + return TRI->isInAllocatableClass(PhysReg) && !isReserved(PhysReg); + } //===--------------------------------------------------------------------===// // LiveIn/LiveOut Management |