| //===-- ARM64Subtarget.cpp - ARM64 Subtarget 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 implements the ARM64 specific subclass of TargetSubtarget. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "ARM64InstrInfo.h" |
| #include "ARM64Subtarget.h" |
| #include "llvm/ADT/SmallVector.h" |
| #include "llvm/CodeGen/MachineScheduler.h" |
| #include "llvm/IR/GlobalValue.h" |
| #include "llvm/Support/TargetRegistry.h" |
| |
| using namespace llvm; |
| |
| #define DEBUG_TYPE "arm64-subtarget" |
| |
| #define GET_SUBTARGETINFO_CTOR |
| #define GET_SUBTARGETINFO_TARGET_DESC |
| #include "ARM64GenSubtargetInfo.inc" |
| |
| ARM64Subtarget::ARM64Subtarget(const std::string &TT, const std::string &CPU, |
| const std::string &FS, bool LittleEndian) |
| : ARM64GenSubtargetInfo(TT, CPU, FS), ARMProcFamily(Others), |
| HasFPARMv8(false), HasNEON(false), HasCrypto(false), HasCRC(false), |
| HasZeroCycleRegMove(false), HasZeroCycleZeroing(false), |
| CPUString(CPU), TargetTriple(TT), IsLittleEndian(LittleEndian) { |
| // Determine default and user-specified characteristics |
| |
| if (CPUString.empty()) |
| CPUString = "generic"; |
| |
| ParseSubtargetFeatures(CPUString, FS); |
| } |
| |
| /// ClassifyGlobalReference - Find the target operand flags that describe |
| /// how a global value should be referenced for the current subtarget. |
| unsigned char |
| ARM64Subtarget::ClassifyGlobalReference(const GlobalValue *GV, |
| const TargetMachine &TM) const { |
| |
| // Determine whether this is a reference to a definition or a declaration. |
| // Materializable GVs (in JIT lazy compilation mode) do not require an extra |
| // load from stub. |
| bool isDecl = GV->hasAvailableExternallyLinkage(); |
| if (GV->isDeclaration() && !GV->isMaterializable()) |
| isDecl = true; |
| |
| // MachO large model always goes via a GOT, simply to get a single 8-byte |
| // absolute relocation on all global addresses. |
| if (TM.getCodeModel() == CodeModel::Large && isTargetMachO()) |
| return ARM64II::MO_GOT; |
| |
| // The small code mode's direct accesses use ADRP, which cannot necessarily |
| // produce the value 0 (if the code is above 4GB). Therefore they must use the |
| // GOT. |
| if (TM.getCodeModel() == CodeModel::Small && GV->isWeakForLinker() && isDecl) |
| return ARM64II::MO_GOT; |
| |
| // If symbol visibility is hidden, the extra load is not needed if |
| // the symbol is definitely defined in the current translation unit. |
| |
| // The handling of non-hidden symbols in PIC mode is rather target-dependent: |
| // + On MachO, if the symbol is defined in this module the GOT can be |
| // skipped. |
| // + On ELF, the R_AARCH64_COPY relocation means that even symbols actually |
| // defined could end up in unexpected places. Use a GOT. |
| if (TM.getRelocationModel() != Reloc::Static && GV->hasDefaultVisibility()) { |
| if (isTargetMachO()) |
| return (isDecl || GV->isWeakForLinker()) ? ARM64II::MO_GOT |
| : ARM64II::MO_NO_FLAG; |
| else |
| // No need to go through the GOT for local symbols on ELF. |
| return GV->hasLocalLinkage() ? ARM64II::MO_NO_FLAG : ARM64II::MO_GOT; |
| } |
| |
| return ARM64II::MO_NO_FLAG; |
| } |
| |
| /// This function returns the name of a function which has an interface |
| /// like the non-standard bzero function, if such a function exists on |
| /// the current subtarget and it is considered prefereable over |
| /// memset with zero passed as the second argument. Otherwise it |
| /// returns null. |
| const char *ARM64Subtarget::getBZeroEntry() const { |
| // At the moment, always prefer bzero. |
| return "bzero"; |
| } |
| |
| void ARM64Subtarget::overrideSchedPolicy(MachineSchedPolicy &Policy, |
| MachineInstr *begin, MachineInstr *end, |
| unsigned NumRegionInstrs) const { |
| // LNT run (at least on Cyclone) showed reasonably significant gains for |
| // bi-directional scheduling. 253.perlbmk. |
| Policy.OnlyTopDown = false; |
| Policy.OnlyBottomUp = false; |
| } |