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https://github.com/c64scene-ar/llvm-6502.git
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actually *removes* one of the operands, instead of just assigning both operands the same register. This make reasoning about instructions unnecessarily complex, because you need to know if you are before or after register allocation to match up operand #'s with the target description file. Changing this also gets rid of a bunch of hacky code in various places. This patch also includes changes to fold loads into cmp/test instructions in the X86 backend, along with a significant simplification to the X86 spill folding code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30108 91177308-0d34-0410-b5e6-96231b3b80d8
170 lines
5.9 KiB
C++
170 lines
5.9 KiB
C++
//===-- llvm/CodeGen/VirtRegMap.h - Virtual Register Map -*- C++ -*--------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a virtual register map. This maps virtual registers to
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// physical registers and virtual registers to stack slots. It is created and
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// updated by a register allocator and then used by a machine code rewriter that
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// adds spill code and rewrites virtual into physical register references.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_VIRTREGMAP_H
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#define LLVM_CODEGEN_VIRTREGMAP_H
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#include "llvm/Target/MRegisterInfo.h"
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#include "llvm/ADT/DenseMap.h"
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#include <map>
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namespace llvm {
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class MachineInstr;
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class TargetInstrInfo;
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class VirtRegMap {
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public:
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enum ModRef { isRef = 1, isMod = 2, isModRef = 3 };
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typedef std::multimap<MachineInstr*,
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std::pair<unsigned, ModRef> > MI2VirtMapTy;
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private:
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const TargetInstrInfo &TII;
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MachineFunction &MF;
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/// Virt2PhysMap - This is a virtual to physical register
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/// mapping. Each virtual register is required to have an entry in
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/// it; even spilled virtual registers (the register mapped to a
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/// spilled register is the temporary used to load it from the
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/// stack).
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DenseMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap;
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/// Virt2StackSlotMap - This is virtual register to stack slot
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/// mapping. Each spilled virtual register has an entry in it
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/// which corresponds to the stack slot this register is spilled
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/// at.
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DenseMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
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/// MI2VirtMap - This is MachineInstr to virtual register
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/// mapping. In the case of memory spill code being folded into
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/// instructions, we need to know which virtual register was
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/// read/written by this instruction.
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MI2VirtMapTy MI2VirtMap;
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VirtRegMap(const VirtRegMap&); // DO NOT IMPLEMENT
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void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
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enum {
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NO_PHYS_REG = 0,
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NO_STACK_SLOT = ~0 >> 1
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};
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public:
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VirtRegMap(MachineFunction &mf);
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void grow();
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/// @brief returns true if the specified virtual register is
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/// mapped to a physical register
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bool hasPhys(unsigned virtReg) const {
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return getPhys(virtReg) != NO_PHYS_REG;
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}
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/// @brief returns the physical register mapped to the specified
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/// virtual register
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unsigned getPhys(unsigned virtReg) const {
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assert(MRegisterInfo::isVirtualRegister(virtReg));
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return Virt2PhysMap[virtReg];
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}
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/// @brief creates a mapping for the specified virtual register to
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/// the specified physical register
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void assignVirt2Phys(unsigned virtReg, unsigned physReg) {
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assert(MRegisterInfo::isVirtualRegister(virtReg) &&
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MRegisterInfo::isPhysicalRegister(physReg));
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assert(Virt2PhysMap[virtReg] == NO_PHYS_REG &&
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"attempt to assign physical register to already mapped "
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"virtual register");
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Virt2PhysMap[virtReg] = physReg;
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}
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/// @brief clears the specified virtual register's, physical
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/// register mapping
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void clearVirt(unsigned virtReg) {
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assert(MRegisterInfo::isVirtualRegister(virtReg));
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assert(Virt2PhysMap[virtReg] != NO_PHYS_REG &&
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"attempt to clear a not assigned virtual register");
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Virt2PhysMap[virtReg] = NO_PHYS_REG;
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}
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/// @brief clears all virtual to physical register mappings
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void clearAllVirt() {
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Virt2PhysMap.clear();
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grow();
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}
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/// @brief returns true is the specified virtual register is
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/// mapped to a stack slot
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bool hasStackSlot(unsigned virtReg) const {
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return getStackSlot(virtReg) != NO_STACK_SLOT;
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}
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/// @brief returns the stack slot mapped to the specified virtual
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/// register
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int getStackSlot(unsigned virtReg) const {
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assert(MRegisterInfo::isVirtualRegister(virtReg));
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return Virt2StackSlotMap[virtReg];
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}
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/// @brief create a mapping for the specifed virtual register to
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/// the next available stack slot
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int assignVirt2StackSlot(unsigned virtReg);
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/// @brief create a mapping for the specified virtual register to
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/// the specified stack slot
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void assignVirt2StackSlot(unsigned virtReg, int frameIndex);
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/// @brief Updates information about the specified virtual register's value
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/// folded into newMI machine instruction. The OpNum argument indicates the
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/// operand number of OldMI that is folded.
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void virtFolded(unsigned VirtReg, MachineInstr *OldMI, unsigned OpNum,
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MachineInstr *NewMI);
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/// @brief returns the virtual registers' values folded in memory
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/// operands of this instruction
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std::pair<MI2VirtMapTy::const_iterator, MI2VirtMapTy::const_iterator>
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getFoldedVirts(MachineInstr* MI) const {
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return MI2VirtMap.equal_range(MI);
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}
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/// RemoveFromFoldedVirtMap - If the specified machine instruction is in
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/// the folded instruction map, remove its entry from the map.
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void RemoveFromFoldedVirtMap(MachineInstr *MI) {
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MI2VirtMap.erase(MI);
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}
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void print(std::ostream &OS) const;
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void dump() const;
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};
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inline std::ostream &operator<<(std::ostream &OS, const VirtRegMap &VRM) {
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VRM.print(OS);
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return OS;
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}
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/// Spiller interface: Implementations of this interface assign spilled
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/// virtual registers to stack slots, rewriting the code.
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struct Spiller {
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virtual ~Spiller();
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virtual bool runOnMachineFunction(MachineFunction &MF,
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VirtRegMap &VRM) = 0;
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};
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/// createSpiller - Create an return a spiller object, as specified on the
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/// command line.
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Spiller* createSpiller();
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} // End llvm namespace
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#endif
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