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llvm-mirror/include/llvm/Target/TargetInstrInfo.h
Chris Lattner 5fd145d9c4 add a hook to insert a noop
llvm-svn: 26560
2006-03-05 23:48:51 +00:00

353 lines
13 KiB
C++

//===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and 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/Support/DataTypes.h"
#include <vector>
#include <cassert>
namespace llvm {
class MachineInstr;
class TargetMachine;
class Value;
class Type;
class Instruction;
class Constant;
class Function;
class MachineCodeForInstruction;
class TargetRegisterClass;
//---------------------------------------------------------------------------
// 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_NOP_FLAG = 1 << 0;
const unsigned M_BRANCH_FLAG = 1 << 1;
const unsigned M_CALL_FLAG = 1 << 2;
const unsigned M_RET_FLAG = 1 << 3;
const unsigned M_BARRIER_FLAG = 1 << 4;
const unsigned M_DELAY_SLOT_FLAG = 1 << 5;
const unsigned M_CC_FLAG = 1 << 6;
const unsigned M_LOAD_FLAG = 1 << 7;
const unsigned M_STORE_FLAG = 1 << 8;
// M_2_ADDR_FLAG - 3-addr instructions which really work like 2-addr ones.
const unsigned M_2_ADDR_FLAG = 1 << 9;
// M_CONVERTIBLE_TO_3_ADDR - This is a M_2_ADDR_FLAG 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 << 10;
// 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 << 11;
// 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 << 12;
// 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 << 13;
/// 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 of the operand if the
/// operand is a register. If not, this contains null.
const TargetRegisterClass *RegClass;
/// Currently no other information.
};
class TargetInstrDescriptor {
public:
const char * Name; // Assembly language mnemonic for the opcode.
int numOperands; // Number of args; -1 if variable #args
int resultPos; // Position of the result; -1 if no result
unsigned maxImmedConst; // Largest +ve constant in IMMED field or 0.
bool immedIsSignExtended; // Is IMMED field sign-extended? If so,
// smallest -ve value is -(maxImmedConst+1).
unsigned numDelaySlots; // Number of delay slots after instruction
unsigned latency; // Latency in machine cycles
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.
};
//---------------------------------------------------------------------------
///
/// 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
};
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;
}
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 isTwoAddrInstr(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_2_ADDR_FLAG;
}
bool isTerminatorInstr(unsigned Opcode) const {
return get(Opcode).Flags & M_TERMINATOR_FLAG;
}
bool isBranch(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_BRANCH_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;
}
/// usesCustomDAGSchedInsertionHook - Return true if this instruction requires
/// custom insertion support when the DAG scheduler is inserting it into a
/// machine basic block.
bool usesCustomDAGSchedInsertionHook(unsigned Opcode) const {
return get(Opcode).Flags & M_USES_CUSTOM_DAG_SCHED_INSERTION;
}
/// 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 a true
/// three-address instruction 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 new instruction.
///
virtual MachineInstr *convertToThreeAddress(MachineInstr *TA) 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;
/// Insert a goto (unconditional branch) sequence to TMBB, at the
/// end of MBB
virtual void insertGoto(MachineBasicBlock& MBB,
MachineBasicBlock& TMBB) const {
assert(0 && "Target didn't implement insertGoto!");
}
/// Reverses the branch condition of the MachineInstr pointed by
/// MI. The instruction is replaced and the new MI is returned.
virtual MachineBasicBlock::iterator
reverseBranchCondition(MachineBasicBlock::iterator MI) const {
assert(0 && "Target didn't implement reverseBranchCondition!");
abort();
return MI;
}
/// 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();
}
//-------------------------------------------------------------------------
// Code generation support for creating individual machine instructions
//
// WARNING: These methods are Sparc specific
//
// DO NOT USE ANY OF THESE METHODS THEY ARE DEPRECATED!
//
//-------------------------------------------------------------------------
unsigned getNumDelaySlots(MachineOpCode Opcode) const {
return get(Opcode).numDelaySlots;
}
bool isCCInstr(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_CC_FLAG;
}
bool isNop(MachineOpCode Opcode) const {
return get(Opcode).Flags & M_NOP_FLAG;
}
/// hasDelaySlot - Returns true if the specified instruction has a delay slot
/// which must be filled by the code generator.
bool hasDelaySlot(unsigned Opcode) const {
return get(Opcode).Flags & M_DELAY_SLOT_FLAG;
}
virtual bool hasResultInterlock(MachineOpCode Opcode) const {
return true;
}
//
// Latencies for individual instructions and instruction pairs
//
virtual int minLatency(MachineOpCode Opcode) const {
return get(Opcode).latency;
}
virtual int maxLatency(MachineOpCode Opcode) const {
return get(Opcode).latency;
}
//
// Which operand holds an immediate constant? Returns -1 if none
//
virtual int getImmedConstantPos(MachineOpCode Opcode) const {
return -1; // immediate position is machine specific, so say -1 == "none"
}
// Check if the specified constant fits in the immediate field
// of this machine instruction
//
virtual bool constantFitsInImmedField(MachineOpCode Opcode,
int64_t intValue) const;
// Return the largest positive constant that can be held in the IMMED field
// of this machine instruction.
// isSignExtended is set to true if the value is sign-extended before use
// (this is true for all immediate fields in SPARC instructions).
// Return 0 if the instruction has no IMMED field.
//
virtual uint64_t maxImmedConstant(MachineOpCode Opcode,
bool &isSignExtended) const {
isSignExtended = get(Opcode).immedIsSignExtended;
return get(Opcode).maxImmedConst;
}
};
} // End llvm namespace
#endif