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llvm-6502/include/llvm/Target/TargetInstrInfo.h
Owen Anderson d94b6a16fe Move some more functionality from MRegisterInfo to TargetInstrInfo. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45603 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-04 23:57:37 +00:00

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//===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes the target machine instructions to the code generator.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETINSTRINFO_H
#define LLVM_TARGET_TARGETINSTRINFO_H
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Support/DataTypes.h"
#include <vector>
#include <cassert>
namespace llvm {
class MachineInstr;
class TargetMachine;
class TargetRegisterClass;
class LiveVariables;
class CalleeSavedInfo;
template<class T> class SmallVectorImpl;
//---------------------------------------------------------------------------
// Data types used to define information about a single machine instruction
//---------------------------------------------------------------------------
typedef short MachineOpCode;
typedef unsigned InstrSchedClass;
//---------------------------------------------------------------------------
// struct TargetInstrDescriptor:
// Predefined information about each machine instruction.
// Designed to initialized statically.
//
const unsigned M_BRANCH_FLAG = 1 << 0;
const unsigned M_CALL_FLAG = 1 << 1;
const unsigned M_RET_FLAG = 1 << 2;
const unsigned M_BARRIER_FLAG = 1 << 3;
const unsigned M_DELAY_SLOT_FLAG = 1 << 4;
const unsigned M_LOAD_FLAG = 1 << 5;
const unsigned M_STORE_FLAG = 1 << 6;
const unsigned M_INDIRECT_FLAG = 1 << 7;
const unsigned M_IMPLICIT_DEF_FLAG = 1 << 8;
// M_CONVERTIBLE_TO_3_ADDR - This is a 2-address instruction which can be
// changed into a 3-address instruction if the first two operands cannot be
// assigned to the same register. The target must implement the
// TargetInstrInfo::convertToThreeAddress method for this instruction.
const unsigned M_CONVERTIBLE_TO_3_ADDR = 1 << 9;
// This M_COMMUTABLE - is a 2- or 3-address instruction (of the form X = op Y,
// Z), which produces the same result if Y and Z are exchanged.
const unsigned M_COMMUTABLE = 1 << 10;
// M_TERMINATOR_FLAG - Is this instruction part of the terminator for a basic
// block? Typically this is things like return and branch instructions.
// Various passes use this to insert code into the bottom of a basic block, but
// before control flow occurs.
const unsigned M_TERMINATOR_FLAG = 1 << 11;
// M_USES_CUSTOM_DAG_SCHED_INSERTION - Set if this instruction requires custom
// insertion support when the DAG scheduler is inserting it into a machine basic
// block.
const unsigned M_USES_CUSTOM_DAG_SCHED_INSERTION = 1 << 12;
// M_VARIABLE_OPS - Set if this instruction can have a variable number of extra
// operands in addition to the minimum number operands specified.
const unsigned M_VARIABLE_OPS = 1 << 13;
// M_PREDICABLE - Set if this instruction has a predicate operand that
// controls execution. It may be set to 'always'.
const unsigned M_PREDICABLE = 1 << 14;
// M_REMATERIALIZIBLE - Set if this instruction can be trivally re-materialized
// at any time, e.g. constant generation, load from constant pool.
const unsigned M_REMATERIALIZIBLE = 1 << 15;
// M_NOT_DUPLICABLE - Set if this instruction cannot be safely duplicated.
// (e.g. instructions with unique labels attached).
const unsigned M_NOT_DUPLICABLE = 1 << 16;
// M_HAS_OPTIONAL_DEF - Set if this instruction has an optional definition, e.g.
// ARM instructions which can set condition code if 's' bit is set.
const unsigned M_HAS_OPTIONAL_DEF = 1 << 17;
// M_NEVER_HAS_SIDE_EFFECTS - Set if this instruction has no side effects that
// are not captured by any operands of the instruction or other flags, and when
// *all* instances of the instruction of that opcode have no side effects.
//
// Note: This and M_MAY_HAVE_SIDE_EFFECTS are mutually exclusive. You can't set
// both! If neither flag is set, then the instruction *always* has side effects.
const unsigned M_NEVER_HAS_SIDE_EFFECTS = 1 << 18;
// M_MAY_HAVE_SIDE_EFFECTS - Set if some instances of this instruction can have
// side effects. The virtual method "isReallySideEffectFree" is called to
// determine this. Load instructions are an example of where this is useful. In
// general, loads always have side effects. However, loads from constant pools
// don't. We let the specific back end make this determination.
//
// Note: This and M_NEVER_HAS_SIDE_EFFECTS are mutually exclusive. You can't set
// both! If neither flag is set, then the instruction *always* has side effects.
const unsigned M_MAY_HAVE_SIDE_EFFECTS = 1 << 19;
// Machine operand flags
// M_LOOK_UP_PTR_REG_CLASS - Set if this operand is a pointer value and it
// requires a callback to look up its register class.
const unsigned M_LOOK_UP_PTR_REG_CLASS = 1 << 0;
/// M_PREDICATE_OPERAND - Set if this is one of the operands that made up of the
/// predicate operand that controls an M_PREDICATED instruction.
const unsigned M_PREDICATE_OPERAND = 1 << 1;
/// M_OPTIONAL_DEF_OPERAND - Set if this operand is a optional def.
///
const unsigned M_OPTIONAL_DEF_OPERAND = 1 << 2;
namespace TOI {
// Operand constraints: only "tied_to" for now.
enum OperandConstraint {
TIED_TO = 0 // Must be allocated the same register as.
};
}
/// TargetOperandInfo - This holds information about one operand of a machine
/// instruction, indicating the register class for register operands, etc.
///
class TargetOperandInfo {
public:
/// RegClass - This specifies the register class enumeration of the operand
/// if the operand is a register. If not, this contains 0.
unsigned short RegClass;
unsigned short Flags;
/// Lower 16 bits are used to specify which constraints are set. The higher 16
/// bits are used to specify the value of constraints (4 bits each).
unsigned int Constraints;
/// Currently no other information.
};
class TargetInstrDescriptor {
public:
MachineOpCode Opcode; // The opcode.
unsigned short numOperands; // Num of args (may be more if variable_ops).
unsigned short numDefs; // Num of args that are definitions.
const char * Name; // Assembly language mnemonic for the opcode.
InstrSchedClass schedClass; // enum identifying instr sched class
unsigned Flags; // flags identifying machine instr class
unsigned TSFlags; // Target Specific Flag values
const unsigned *ImplicitUses; // Registers implicitly read by this instr
const unsigned *ImplicitDefs; // Registers implicitly defined by this instr
const TargetOperandInfo *OpInfo; // 'numOperands' entries about operands.
/// getOperandConstraint - Returns the value of the specific constraint if
/// it is set. Returns -1 if it is not set.
int getOperandConstraint(unsigned OpNum,
TOI::OperandConstraint Constraint) const {
assert((OpNum < numOperands || (Flags & M_VARIABLE_OPS)) &&
"Invalid operand # of TargetInstrInfo");
if (OpNum < numOperands &&
(OpInfo[OpNum].Constraints & (1 << Constraint))) {
unsigned Pos = 16 + Constraint * 4;
return (int)(OpInfo[OpNum].Constraints >> Pos) & 0xf;
}
return -1;
}
/// findTiedToSrcOperand - Returns the operand that is tied to the specified
/// dest operand. Returns -1 if there isn't one.
int findTiedToSrcOperand(unsigned OpNum) const;
};
//---------------------------------------------------------------------------
///
/// TargetInstrInfo - Interface to description of machine instructions
///
class TargetInstrInfo {
const TargetInstrDescriptor* desc; // raw array to allow static init'n
unsigned NumOpcodes; // number of entries in the desc array
unsigned numRealOpCodes; // number of non-dummy op codes
TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT
void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT
public:
TargetInstrInfo(const TargetInstrDescriptor *desc, unsigned NumOpcodes);
virtual ~TargetInstrInfo();
// Invariant opcodes: All instruction sets have these as their low opcodes.
enum {
PHI = 0,
INLINEASM = 1,
LABEL = 2,
EXTRACT_SUBREG = 3,
INSERT_SUBREG = 4
};
unsigned getNumOpcodes() const { return NumOpcodes; }
/// get - Return the machine instruction descriptor that corresponds to the
/// specified instruction opcode.
///
const TargetInstrDescriptor& get(MachineOpCode Opcode) const {
assert((unsigned)Opcode < NumOpcodes);
return desc[Opcode];
}
const char *getName(MachineOpCode Opcode) const {
return get(Opcode).Name;
}
int getNumOperands(MachineOpCode Opcode) const {
return get(Opcode).numOperands;
}
int getNumDefs(MachineOpCode Opcode) const {
return get(Opcode).numDefs;
}
InstrSchedClass getSchedClass(MachineOpCode Opcode) const {
return get(Opcode).schedClass;
}
const unsigned *getImplicitUses(MachineOpCode Opcode) const {
return get(Opcode).ImplicitUses;
}
const unsigned *getImplicitDefs(MachineOpCode Opcode) const {
return get(Opcode).ImplicitDefs;
}
//
// Query instruction class flags according to the machine-independent
// flags listed above.
//
bool isReturn(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_RET_FLAG;
}
bool isCommutableInstr(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_COMMUTABLE;
}
bool isTerminatorInstr(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_TERMINATOR_FLAG;
}
bool isBranch(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_BRANCH_FLAG;
}
bool isIndirectBranch(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_INDIRECT_FLAG;
}
/// isBarrier - Returns true if the specified instruction stops control flow
/// from executing the instruction immediately following it. Examples include
/// unconditional branches and return instructions.
bool isBarrier(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_BARRIER_FLAG;
}
bool isCall(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_CALL_FLAG;
}
bool isLoad(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_LOAD_FLAG;
}
bool isStore(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_STORE_FLAG;
}
/// hasDelaySlot - Returns true if the specified instruction has a delay slot
/// which must be filled by the code generator.
bool hasDelaySlot(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_DELAY_SLOT_FLAG;
}
/// usesCustomDAGSchedInsertionHook - Return true if this instruction requires
/// custom insertion support when the DAG scheduler is inserting it into a
/// machine basic block.
bool usesCustomDAGSchedInsertionHook(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION;
}
bool hasVariableOperands(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_VARIABLE_OPS;
}
bool isPredicable(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_PREDICABLE;
}
bool isNotDuplicable(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_NOT_DUPLICABLE;
}
bool hasOptionalDef(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_HAS_OPTIONAL_DEF;
}
/// isTriviallyReMaterializable - Return true if the instruction is trivially
/// rematerializable, meaning it has no side effects and requires no operands
/// that aren't always available.
bool isTriviallyReMaterializable(MachineInstr *MI) const {
return (MI->getInstrDescriptor()->Flags & M_REMATERIALIZIBLE) &&
isReallyTriviallyReMaterializable(MI);
}
/// hasUnmodelledSideEffects - Returns true if the instruction has side
/// effects that are not captured by any operands of the instruction or other
/// flags.
bool hasUnmodelledSideEffects(MachineInstr *MI) const {
const TargetInstrDescriptor *TID = MI->getInstrDescriptor();
if (!(TID->Flags & M_NEVER_HAS_SIDE_EFFECTS ||
TID->Flags & M_MAY_HAVE_SIDE_EFFECTS)) return true;
if (TID->Flags & M_NEVER_HAS_SIDE_EFFECTS) return false;
return !isReallySideEffectFree(MI); // May have side effects
}
protected:
/// isReallyTriviallyReMaterializable - For instructions with opcodes for
/// which the M_REMATERIALIZABLE flag is set, this function tests whether the
/// instruction itself is actually trivially rematerializable, considering
/// its operands. This is used for targets that have instructions that are
/// only trivially rematerializable for specific uses. This predicate must
/// return false if the instruction has any side effects other than
/// producing a value, or if it requres any address registers that are not
/// always available.
virtual bool isReallyTriviallyReMaterializable(MachineInstr *MI) const {
return true;
}
/// isReallySideEffectFree - If the M_MAY_HAVE_SIDE_EFFECTS flag is set, this
/// method is called to determine if the specific instance of this
/// instruction has side effects. This is useful in cases of instructions,
/// like loads, which generally always have side effects. A load from a
/// constant pool doesn't have side effects, though. So we need to
/// differentiate it from the general case.
virtual bool isReallySideEffectFree(MachineInstr *MI) const {
return false;
}
public:
/// getOperandConstraint - Returns the value of the specific constraint if
/// it is set. Returns -1 if it is not set.
int getOperandConstraint(MachineOpCode Opcode, unsigned OpNum,
TOI::OperandConstraint Constraint) const {
return get(Opcode).getOperandConstraint(OpNum, Constraint);
}
/// Return true if the instruction is a register to register move
/// and leave the source and dest operands in the passed parameters.
virtual bool isMoveInstr(const MachineInstr& MI,
unsigned& sourceReg,
unsigned& destReg) const {
return false;
}
/// isLoadFromStackSlot - If the specified machine instruction is a direct
/// load from a stack slot, return the virtual or physical register number of
/// the destination along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than loading from the stack slot.
virtual unsigned isLoadFromStackSlot(MachineInstr *MI, int &FrameIndex) const{
return 0;
}
/// isStoreToStackSlot - If the specified machine instruction is a direct
/// store to a stack slot, return the virtual or physical register number of
/// the source reg along with the FrameIndex of the loaded stack slot. If
/// not, return 0. This predicate must return 0 if the instruction has
/// any side effects other than storing to the stack slot.
virtual unsigned isStoreToStackSlot(MachineInstr *MI, int &FrameIndex) const {
return 0;
}
/// convertToThreeAddress - This method must be implemented by targets that
/// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target
/// may be able to convert a two-address instruction into one or more true
/// three-address instructions on demand. This allows the X86 target (for
/// example) to convert ADD and SHL instructions into LEA instructions if they
/// would require register copies due to two-addressness.
///
/// This method returns a null pointer if the transformation cannot be
/// performed, otherwise it returns the last new instruction.
///
virtual MachineInstr *
convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI, LiveVariables &LV) const {
return 0;
}
/// commuteInstruction - If a target has any instructions that are commutable,
/// but require converting to a different instruction or making non-trivial
/// changes to commute them, this method can overloaded to do this. The
/// default implementation of this method simply swaps the first two operands
/// of MI and returns it.
///
/// If a target wants to make more aggressive changes, they can construct and
/// return a new machine instruction. If an instruction cannot commute, it
/// can also return null.
///
virtual MachineInstr *commuteInstruction(MachineInstr *MI) const = 0;
/// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
/// true if it cannot be understood (e.g. it's a switch dispatch or isn't
/// implemented for a target). Upon success, this returns false and returns
/// with the following information in various cases:
///
/// 1. If this block ends with no branches (it just falls through to its succ)
/// just return false, leaving TBB/FBB null.
/// 2. If this block ends with only an unconditional branch, it sets TBB to be
/// the destination block.
/// 3. If this block ends with an conditional branch and it falls through to
/// an successor block, it sets TBB to be the branch destination block and a
/// list of operands that evaluate the condition. These
/// operands can be passed to other TargetInstrInfo methods to create new
/// branches.
/// 4. If this block ends with an conditional branch and an unconditional
/// block, it returns the 'true' destination in TBB, the 'false' destination
/// in FBB, and a list of operands that evaluate the condition. These
/// operands can be passed to other TargetInstrInfo methods to create new
/// branches.
///
/// Note that RemoveBranch and InsertBranch must be implemented to support
/// cases where this method returns success.
///
virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
std::vector<MachineOperand> &Cond) const {
return true;
}
/// RemoveBranch - Remove the branching code at the end of the specific MBB.
/// this is only invoked in cases where AnalyzeBranch returns success. It
/// returns the number of instructions that were removed.
virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const {
assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!");
return 0;
}
/// InsertBranch - Insert a branch into the end of the specified
/// MachineBasicBlock. This operands to this method are the same as those
/// returned by AnalyzeBranch. This is invoked in cases where AnalyzeBranch
/// returns success and when an unconditional branch (TBB is non-null, FBB is
/// null, Cond is empty) needs to be inserted. It returns the number of
/// instructions inserted.
virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const std::vector<MachineOperand> &Cond) const {
assert(0 && "Target didn't implement TargetInstrInfo::InsertBranch!");
return 0;
}
/// copyRegToReg - Add a copy between a pair of registers
virtual void copyRegToReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SrcReg,
const TargetRegisterClass *DestRC,
const TargetRegisterClass *SrcRC) const {
assert(0 && "Target didn't implement TargetInstrInfo::copyRegToReg!");
}
virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned SrcReg, bool isKill, int FrameIndex,
const TargetRegisterClass *RC) const {
assert(0 && "Target didn't implement TargetInstrInfo::storeRegToStackSlot!");
}
virtual void storeRegToAddr(MachineFunction &MF, unsigned SrcReg, bool isKill,
SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC,
SmallVectorImpl<MachineInstr*> &NewMIs) const {
assert(0 && "Target didn't implement TargetInstrInfo::storeRegToAddr!");
}
virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, int FrameIndex,
const TargetRegisterClass *RC) const {
assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromStackSlot!");
}
virtual void loadRegFromAddr(MachineFunction &MF, unsigned DestReg,
SmallVectorImpl<MachineOperand> &Addr,
const TargetRegisterClass *RC,
SmallVectorImpl<MachineInstr*> &NewMIs) const {
assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromAddr!");
}
/// spillCalleeSavedRegisters - Issues instruction(s) to spill all callee
/// saved registers and returns true if it isn't possible / profitable to do
/// so by issuing a series of store instructions via
/// storeRegToStackSlot(). Returns false otherwise.
virtual bool spillCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI) const {
return false;
}
/// restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee
/// saved registers and returns true if it isn't possible / profitable to do
/// so by issuing a series of load instructions via loadRegToStackSlot().
/// Returns false otherwise.
virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
const std::vector<CalleeSavedInfo> &CSI) const {
return false;
}
/// BlockHasNoFallThrough - Return true if the specified block does not
/// fall-through into its successor block. This is primarily used when a
/// branch is unanalyzable. It is useful for things like unconditional
/// indirect branches (jump tables).
virtual bool BlockHasNoFallThrough(MachineBasicBlock &MBB) const {
return false;
}
/// ReverseBranchCondition - Reverses the branch condition of the specified
/// condition list, returning false on success and true if it cannot be
/// reversed.
virtual bool ReverseBranchCondition(std::vector<MachineOperand> &Cond) const {
return true;
}
/// insertNoop - Insert a noop into the instruction stream at the specified
/// point.
virtual void insertNoop(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI) const {
assert(0 && "Target didn't implement insertNoop!");
abort();
}
/// isPredicated - Returns true if the instruction is already predicated.
///
virtual bool isPredicated(const MachineInstr *MI) const {
return false;
}
/// isUnpredicatedTerminator - Returns true if the instruction is a
/// terminator instruction that has not been predicated.
virtual bool isUnpredicatedTerminator(const MachineInstr *MI) const;
/// PredicateInstruction - Convert the instruction into a predicated
/// instruction. It returns true if the operation was successful.
virtual
bool PredicateInstruction(MachineInstr *MI,
const std::vector<MachineOperand> &Pred) const = 0;
/// SubsumesPredicate - Returns true if the first specified predicate
/// subsumes the second, e.g. GE subsumes GT.
virtual
bool SubsumesPredicate(const std::vector<MachineOperand> &Pred1,
const std::vector<MachineOperand> &Pred2) const {
return false;
}
/// DefinesPredicate - If the specified instruction defines any predicate
/// or condition code register(s) used for predication, returns true as well
/// as the definition predicate(s) by reference.
virtual bool DefinesPredicate(MachineInstr *MI,
std::vector<MachineOperand> &Pred) const {
return false;
}
/// getPointerRegClass - Returns a TargetRegisterClass used for pointer
/// values.
virtual const TargetRegisterClass *getPointerRegClass() const {
assert(0 && "Target didn't implement getPointerRegClass!");
abort();
return 0; // Must return a value in order to compile with VS 2005
}
};
/// TargetInstrInfoImpl - This is the default implementation of
/// TargetInstrInfo, which just provides a couple of default implementations
/// for various methods. This separated out because it is implemented in
/// libcodegen, not in libtarget.
class TargetInstrInfoImpl : public TargetInstrInfo {
protected:
TargetInstrInfoImpl(const TargetInstrDescriptor *desc, unsigned NumOpcodes)
: TargetInstrInfo(desc, NumOpcodes) {}
public:
virtual MachineInstr *commuteInstruction(MachineInstr *MI) const;
virtual bool PredicateInstruction(MachineInstr *MI,
const std::vector<MachineOperand> &Pred) const;
};
} // End llvm namespace
#endif
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