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llvm-6502/lib/Target/ARM/ARMBaseInstrInfo.h
Tom Roeder 63dea2c952 Add Forward Control-Flow Integrity. 
This commit adds a new pass that can inject checks before indirect calls to
make sure that these calls target known locations. It supports three types of
checks and, at compile time, it can take the name of a custom function to call
when an indirect call check fails. The default failure function ignores the
error and continues.

This pass incidentally moves the function JumpInstrTables::transformType from
private to public and makes it static (with a new argument that specifies the
table type to use); this is so that the CFI code can transform function types
at call sites to determine which jump-instruction table to use for the check at
that site.

Also, this removes support for jumptables in ARM, pending further performance
analysis and discussion.

Review: http://reviews.llvm.org/D4167



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221708 91177308-0d34-0410-b5e6-96231b3b80d8
2014-11-11 21:08:02 +00:00

498 lines
21 KiB
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//===-- ARMBaseInstrInfo.h - ARM Base Instruction Information ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Base ARM implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_ARM_ARMBASEINSTRINFO_H
#define LLVM_LIB_TARGET_ARM_ARMBASEINSTRINFO_H
#include "MCTargetDesc/ARMBaseInfo.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Target/TargetInstrInfo.h"
#define GET_INSTRINFO_HEADER
#include "ARMGenInstrInfo.inc"
namespace llvm {
class ARMSubtarget;
class ARMBaseRegisterInfo;
class ARMBaseInstrInfo : public ARMGenInstrInfo {
const ARMSubtarget &Subtarget;
protected:
// Can be only subclassed.
explicit ARMBaseInstrInfo(const ARMSubtarget &STI);
void expandLoadStackGuardBase(MachineBasicBlock::iterator MI,
unsigned LoadImmOpc, unsigned LoadOpc,
Reloc::Model RM) const;
/// Build the equivalent inputs of a REG_SEQUENCE for the given \p MI
/// and \p DefIdx.
/// \p [out] InputRegs of the equivalent REG_SEQUENCE. Each element of
/// the list is modeled as <Reg:SubReg, SubIdx>.
/// E.g., REG_SEQUENCE vreg1:sub1, sub0, vreg2, sub1 would produce
/// two elements:
/// - vreg1:sub1, sub0
/// - vreg2<:0>, sub1
///
/// \returns true if it is possible to build such an input sequence
/// with the pair \p MI, \p DefIdx. False otherwise.
///
/// \pre MI.isRegSequenceLike().
bool getRegSequenceLikeInputs(
const MachineInstr &MI, unsigned DefIdx,
SmallVectorImpl<RegSubRegPairAndIdx> &InputRegs) const override;
/// Build the equivalent inputs of a EXTRACT_SUBREG for the given \p MI
/// and \p DefIdx.
/// \p [out] InputReg of the equivalent EXTRACT_SUBREG.
/// E.g., EXTRACT_SUBREG vreg1:sub1, sub0, sub1 would produce:
/// - vreg1:sub1, sub0
///
/// \returns true if it is possible to build such an input sequence
/// with the pair \p MI, \p DefIdx. False otherwise.
///
/// \pre MI.isExtractSubregLike().
bool getExtractSubregLikeInputs(const MachineInstr &MI, unsigned DefIdx,
RegSubRegPairAndIdx &InputReg) const override;
/// Build the equivalent inputs of a INSERT_SUBREG for the given \p MI
/// and \p DefIdx.
/// \p [out] BaseReg and \p [out] InsertedReg contain
/// the equivalent inputs of INSERT_SUBREG.
/// E.g., INSERT_SUBREG vreg0:sub0, vreg1:sub1, sub3 would produce:
/// - BaseReg: vreg0:sub0
/// - InsertedReg: vreg1:sub1, sub3
///
/// \returns true if it is possible to build such an input sequence
/// with the pair \p MI, \p DefIdx. False otherwise.
///
/// \pre MI.isInsertSubregLike().
bool
getInsertSubregLikeInputs(const MachineInstr &MI, unsigned DefIdx,
RegSubRegPair &BaseReg,
RegSubRegPairAndIdx &InsertedReg) const override;
public:
// Return whether the target has an explicit NOP encoding.
bool hasNOP() const;
// Return the non-pre/post incrementing version of 'Opc'. Return 0
// if there is not such an opcode.
virtual unsigned getUnindexedOpcode(unsigned Opc) const =0;
MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables *LV) const override;
virtual const ARMBaseRegisterInfo &getRegisterInfo() const = 0;
const ARMSubtarget &getSubtarget() const { return Subtarget; }
ScheduleHazardRecognizer *
CreateTargetHazardRecognizer(const TargetSubtargetInfo *STI,
const ScheduleDAG *DAG) const override;
ScheduleHazardRecognizer *
CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
const ScheduleDAG *DAG) const override;
// Branch analysis.
bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify = false) const override;
unsigned RemoveBranch(MachineBasicBlock &MBB) const override;
unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const override;
bool
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
// Predication support.
bool isPredicated(const MachineInstr *MI) const override;
ARMCC::CondCodes getPredicate(const MachineInstr *MI) const {
int PIdx = MI->findFirstPredOperandIdx();
return PIdx != -1 ? (ARMCC::CondCodes)MI->getOperand(PIdx).getImm()
: ARMCC::AL;
}
bool PredicateInstruction(MachineInstr *MI,
const SmallVectorImpl<MachineOperand> &Pred) const override;
bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
const SmallVectorImpl<MachineOperand> &Pred2) const override;
bool DefinesPredicate(MachineInstr *MI,
std::vector<MachineOperand> &Pred) const override;
bool isPredicable(MachineInstr *MI) const override;
/// GetInstSize - Returns the size of the specified MachineInstr.
///
virtual unsigned GetInstSizeInBytes(const MachineInstr* MI) const;
unsigned isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const override;
unsigned isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const override;
unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
int &FrameIndex) const override;
unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
int &FrameIndex) const override;
void copyToCPSR(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned SrcReg, bool KillSrc,
const ARMSubtarget &Subtarget) const;
void copyFromCPSR(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
unsigned DestReg, bool KillSrc,
const ARMSubtarget &Subtarget) const;
void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
DebugLoc DL, unsigned DestReg, unsigned SrcReg,
bool KillSrc) const override;
void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const override;
bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const override;
void reMaterialize(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SubIdx,
const MachineInstr *Orig,
const TargetRegisterInfo &TRI) const override;
MachineInstr *duplicate(MachineInstr *Orig,
MachineFunction &MF) const override;
MachineInstr *commuteInstruction(MachineInstr*,
bool=false) const override;
const MachineInstrBuilder &AddDReg(MachineInstrBuilder &MIB, unsigned Reg,
unsigned SubIdx, unsigned State,
const TargetRegisterInfo *TRI) const;
bool produceSameValue(const MachineInstr *MI0, const MachineInstr *MI1,
const MachineRegisterInfo *MRI) const override;
/// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler to
/// determine if two loads are loading from the same base address. It should
/// only return true if the base pointers are the same and the only
/// differences between the two addresses is the offset. It also returns the
/// offsets by reference.
bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2, int64_t &Offset1,
int64_t &Offset2) const override;
/// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
/// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
/// should be scheduled togther. On some targets if two loads are loading from
/// addresses in the same cache line, it's better if they are scheduled
/// together. This function takes two integers that represent the load offsets
/// from the common base address. It returns true if it decides it's desirable
/// to schedule the two loads together. "NumLoads" is the number of loads that
/// have already been scheduled after Load1.
bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
int64_t Offset1, int64_t Offset2,
unsigned NumLoads) const override;
bool isSchedulingBoundary(const MachineInstr *MI,
const MachineBasicBlock *MBB,
const MachineFunction &MF) const override;
bool isProfitableToIfCvt(MachineBasicBlock &MBB,
unsigned NumCycles, unsigned ExtraPredCycles,
const BranchProbability &Probability) const override;
bool isProfitableToIfCvt(MachineBasicBlock &TMBB, unsigned NumT,
unsigned ExtraT, MachineBasicBlock &FMBB,
unsigned NumF, unsigned ExtraF,
const BranchProbability &Probability) const override;
bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
const BranchProbability &Probability) const override {
return NumCycles == 1;
}
bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
MachineBasicBlock &FMBB) const override;
/// analyzeCompare - For a comparison instruction, return the source registers
/// in SrcReg and SrcReg2 if having two register operands, and the value it
/// compares against in CmpValue. Return true if the comparison instruction
/// can be analyzed.
bool analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
unsigned &SrcReg2, int &CmpMask,
int &CmpValue) const override;
/// optimizeCompareInstr - Convert the instruction to set the zero flag so
/// that we can remove a "comparison with zero"; Remove a redundant CMP
/// instruction if the flags can be updated in the same way by an earlier
/// instruction such as SUB.
bool optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
unsigned SrcReg2, int CmpMask, int CmpValue,
const MachineRegisterInfo *MRI) const override;
bool analyzeSelect(const MachineInstr *MI,
SmallVectorImpl<MachineOperand> &Cond,
unsigned &TrueOp, unsigned &FalseOp,
bool &Optimizable) const override;
MachineInstr *optimizeSelect(MachineInstr *MI, bool) const override;
/// FoldImmediate - 'Reg' is known to be defined by a move immediate
/// instruction, try to fold the immediate into the use instruction.
bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
unsigned Reg, MachineRegisterInfo *MRI) const override;
unsigned getNumMicroOps(const InstrItineraryData *ItinData,
const MachineInstr *MI) const override;
int getOperandLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI, unsigned DefIdx,
const MachineInstr *UseMI,
unsigned UseIdx) const override;
int getOperandLatency(const InstrItineraryData *ItinData,
SDNode *DefNode, unsigned DefIdx,
SDNode *UseNode, unsigned UseIdx) const override;
/// VFP/NEON execution domains.
std::pair<uint16_t, uint16_t>
getExecutionDomain(const MachineInstr *MI) const override;
void setExecutionDomain(MachineInstr *MI, unsigned Domain) const override;
unsigned getPartialRegUpdateClearance(const MachineInstr*, unsigned,
const TargetRegisterInfo*) const override;
void breakPartialRegDependency(MachineBasicBlock::iterator, unsigned,
const TargetRegisterInfo *TRI) const override;
/// Get the number of addresses by LDM or VLDM or zero for unknown.
unsigned getNumLDMAddresses(const MachineInstr *MI) const;
private:
unsigned getInstBundleLength(const MachineInstr *MI) const;
int getVLDMDefCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefClass,
unsigned DefIdx, unsigned DefAlign) const;
int getLDMDefCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefClass,
unsigned DefIdx, unsigned DefAlign) const;
int getVSTMUseCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &UseMCID,
unsigned UseClass,
unsigned UseIdx, unsigned UseAlign) const;
int getSTMUseCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &UseMCID,
unsigned UseClass,
unsigned UseIdx, unsigned UseAlign) const;
int getOperandLatency(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefIdx, unsigned DefAlign,
const MCInstrDesc &UseMCID,
unsigned UseIdx, unsigned UseAlign) const;
unsigned getPredicationCost(const MachineInstr *MI) const override;
unsigned getInstrLatency(const InstrItineraryData *ItinData,
const MachineInstr *MI,
unsigned *PredCost = nullptr) const override;
int getInstrLatency(const InstrItineraryData *ItinData,
SDNode *Node) const override;
bool hasHighOperandLatency(const InstrItineraryData *ItinData,
const MachineRegisterInfo *MRI,
const MachineInstr *DefMI, unsigned DefIdx,
const MachineInstr *UseMI,
unsigned UseIdx) const override;
bool hasLowDefLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI,
unsigned DefIdx) const override;
/// verifyInstruction - Perform target specific instruction verification.
bool verifyInstruction(const MachineInstr *MI,
StringRef &ErrInfo) const override;
virtual void expandLoadStackGuard(MachineBasicBlock::iterator MI,
Reloc::Model RM) const = 0;
private:
/// Modeling special VFP / NEON fp MLA / MLS hazards.
/// MLxEntryMap - Map fp MLA / MLS to the corresponding entry in the internal
/// MLx table.
DenseMap<unsigned, unsigned> MLxEntryMap;
/// MLxHazardOpcodes - Set of add / sub and multiply opcodes that would cause
/// stalls when scheduled together with fp MLA / MLS opcodes.
SmallSet<unsigned, 16> MLxHazardOpcodes;
public:
/// isFpMLxInstruction - Return true if the specified opcode is a fp MLA / MLS
/// instruction.
bool isFpMLxInstruction(unsigned Opcode) const {
return MLxEntryMap.count(Opcode);
}
/// isFpMLxInstruction - This version also returns the multiply opcode and the
/// addition / subtraction opcode to expand to. Return true for 'HasLane' for
/// the MLX instructions with an extra lane operand.
bool isFpMLxInstruction(unsigned Opcode, unsigned &MulOpc,
unsigned &AddSubOpc, bool &NegAcc,
bool &HasLane) const;
/// canCauseFpMLxStall - Return true if an instruction of the specified opcode
/// will cause stalls when scheduled after (within 4-cycle window) a fp
/// MLA / MLS instruction.
bool canCauseFpMLxStall(unsigned Opcode) const {
return MLxHazardOpcodes.count(Opcode);
}
/// Returns true if the instruction has a shift by immediate that can be
/// executed in one cycle less.
bool isSwiftFastImmShift(const MachineInstr *MI) const;
};
static inline
const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
}
static inline
const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
return MIB.addReg(0);
}
static inline
const MachineInstrBuilder &AddDefaultT1CC(const MachineInstrBuilder &MIB,
bool isDead = false) {
return MIB.addReg(ARM::CPSR, getDefRegState(true) | getDeadRegState(isDead));
}
static inline
const MachineInstrBuilder &AddNoT1CC(const MachineInstrBuilder &MIB) {
return MIB.addReg(0);
}
static inline
bool isUncondBranchOpcode(int Opc) {
return Opc == ARM::B || Opc == ARM::tB || Opc == ARM::t2B;
}
static inline
bool isCondBranchOpcode(int Opc) {
return Opc == ARM::Bcc || Opc == ARM::tBcc || Opc == ARM::t2Bcc;
}
static inline
bool isJumpTableBranchOpcode(int Opc) {
return Opc == ARM::BR_JTr || Opc == ARM::BR_JTm || Opc == ARM::BR_JTadd ||
Opc == ARM::tBR_JTr || Opc == ARM::t2BR_JT;
}
static inline
bool isIndirectBranchOpcode(int Opc) {
return Opc == ARM::BX || Opc == ARM::MOVPCRX || Opc == ARM::tBRIND;
}
static inline bool isPopOpcode(int Opc) {
return Opc == ARM::tPOP_RET || Opc == ARM::LDMIA_RET ||
Opc == ARM::t2LDMIA_RET || Opc == ARM::tPOP || Opc == ARM::LDMIA_UPD ||
Opc == ARM::t2LDMIA_UPD || Opc == ARM::VLDMDIA_UPD;
}
static inline bool isPushOpcode(int Opc) {
return Opc == ARM::tPUSH || Opc == ARM::t2STMDB_UPD ||
Opc == ARM::STMDB_UPD || Opc == ARM::VSTMDDB_UPD;
}
/// getInstrPredicate - If instruction is predicated, returns its predicate
/// condition, otherwise returns AL. It also returns the condition code
/// register by reference.
ARMCC::CondCodes getInstrPredicate(const MachineInstr *MI, unsigned &PredReg);
int getMatchingCondBranchOpcode(int Opc);
/// Determine if MI can be folded into an ARM MOVCC instruction, and return the
/// opcode of the SSA instruction representing the conditional MI.
unsigned canFoldARMInstrIntoMOVCC(unsigned Reg,
MachineInstr *&MI,
const MachineRegisterInfo &MRI);
/// Map pseudo instructions that imply an 'S' bit onto real opcodes. Whether
/// the instruction is encoded with an 'S' bit is determined by the optional
/// CPSR def operand.
unsigned convertAddSubFlagsOpcode(unsigned OldOpc);
/// emitARMRegPlusImmediate / emitT2RegPlusImmediate - Emits a series of
/// instructions to materializea destreg = basereg + immediate in ARM / Thumb2
/// code.
void emitARMRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg, int NumBytes,
ARMCC::CondCodes Pred, unsigned PredReg,
const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
void emitT2RegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg, int NumBytes,
ARMCC::CondCodes Pred, unsigned PredReg,
const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg,
int NumBytes, const TargetInstrInfo &TII,
const ARMBaseRegisterInfo& MRI,
unsigned MIFlags = 0);
/// Tries to add registers to the reglist of a given base-updating
/// push/pop instruction to adjust the stack by an additional
/// NumBytes. This can save a few bytes per function in code-size, but
/// obviously generates more memory traffic. As such, it only takes
/// effect in functions being optimised for size.
bool tryFoldSPUpdateIntoPushPop(const ARMSubtarget &Subtarget,
MachineFunction &MF, MachineInstr *MI,
unsigned NumBytes);
/// rewriteARMFrameIndex / rewriteT2FrameIndex -
/// Rewrite MI to access 'Offset' bytes from the FP. Return false if the
/// offset could not be handled directly in MI, and return the left-over
/// portion by reference.
bool rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII);
bool rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII);
} // End llvm namespace
#endif
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