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1a4d82fc | 1 | //===-- AArch64Subtarget.cpp - AArch64 Subtarget Information ----*- C++ -*-===// |
970d7e83 LB |
2 | // |
3 | // The LLVM Compiler Infrastructure | |
4 | // | |
5 | // This file is distributed under the University of Illinois Open Source | |
6 | // License. See LICENSE.TXT for details. | |
7 | // | |
8 | //===----------------------------------------------------------------------===// | |
9 | // | |
1a4d82fc | 10 | // This file implements the AArch64 specific subclass of TargetSubtarget. |
970d7e83 LB |
11 | // |
12 | //===----------------------------------------------------------------------===// | |
13 | ||
1a4d82fc | 14 | #include "AArch64InstrInfo.h" |
85aaf69f | 15 | #include "AArch64PBQPRegAlloc.h" |
970d7e83 | 16 | #include "AArch64Subtarget.h" |
970d7e83 | 17 | #include "llvm/ADT/SmallVector.h" |
1a4d82fc JJ |
18 | #include "llvm/CodeGen/MachineScheduler.h" |
19 | #include "llvm/IR/GlobalValue.h" | |
20 | #include "llvm/Support/TargetRegistry.h" | |
21 | ||
22 | using namespace llvm; | |
23 | ||
24 | #define DEBUG_TYPE "aarch64-subtarget" | |
970d7e83 | 25 | |
970d7e83 | 26 | #define GET_SUBTARGETINFO_CTOR |
1a4d82fc | 27 | #define GET_SUBTARGETINFO_TARGET_DESC |
970d7e83 LB |
28 | #include "AArch64GenSubtargetInfo.inc" |
29 | ||
1a4d82fc JJ |
30 | static cl::opt<bool> |
31 | EnableEarlyIfConvert("aarch64-early-ifcvt", cl::desc("Enable the early if " | |
32 | "converter pass"), cl::init(true), cl::Hidden); | |
33 | ||
34 | AArch64Subtarget & | |
35 | AArch64Subtarget::initializeSubtargetDependencies(StringRef FS) { | |
36 | // Determine default and user-specified characteristics | |
37 | ||
38 | if (CPUString.empty()) | |
39 | CPUString = "generic"; | |
40 | ||
41 | ParseSubtargetFeatures(CPUString, FS); | |
42 | return *this; | |
43 | } | |
44 | ||
45 | AArch64Subtarget::AArch64Subtarget(const std::string &TT, | |
46 | const std::string &CPU, | |
85aaf69f SL |
47 | const std::string &FS, |
48 | const TargetMachine &TM, bool LittleEndian) | |
1a4d82fc JJ |
49 | : AArch64GenSubtargetInfo(TT, CPU, FS), ARMProcFamily(Others), |
50 | HasFPARMv8(false), HasNEON(false), HasCrypto(false), HasCRC(false), | |
51 | HasZeroCycleRegMove(false), HasZeroCycleZeroing(false), CPUString(CPU), | |
52 | TargetTriple(TT), | |
53 | // This nested ternary is horrible, but DL needs to be properly | |
54 | // initialized | |
55 | // before TLInfo is constructed. | |
56 | DL(isTargetMachO() | |
57 | ? "e-m:o-i64:64-i128:128-n32:64-S128" | |
58 | : (LittleEndian ? "e-m:e-i64:64-i128:128-n32:64-S128" | |
59 | : "E-m:e-i64:64-i128:128-n32:64-S128")), | |
60 | FrameLowering(), InstrInfo(initializeSubtargetDependencies(FS)), | |
61 | TSInfo(&DL), TLInfo(TM) {} | |
62 | ||
63 | /// ClassifyGlobalReference - Find the target operand flags that describe | |
64 | /// how a global value should be referenced for the current subtarget. | |
65 | unsigned char | |
66 | AArch64Subtarget::ClassifyGlobalReference(const GlobalValue *GV, | |
67 | const TargetMachine &TM) const { | |
85aaf69f | 68 | bool isDecl = GV->isDeclarationForLinker(); |
1a4d82fc JJ |
69 | |
70 | // MachO large model always goes via a GOT, simply to get a single 8-byte | |
71 | // absolute relocation on all global addresses. | |
72 | if (TM.getCodeModel() == CodeModel::Large && isTargetMachO()) | |
73 | return AArch64II::MO_GOT; | |
74 | ||
75 | // The small code mode's direct accesses use ADRP, which cannot necessarily | |
76 | // produce the value 0 (if the code is above 4GB). | |
77 | if (TM.getCodeModel() == CodeModel::Small && | |
78 | GV->isWeakForLinker() && isDecl) { | |
79 | // In PIC mode use the GOT, but in absolute mode use a constant pool load. | |
80 | if (TM.getRelocationModel() == Reloc::Static) | |
81 | return AArch64II::MO_CONSTPOOL; | |
82 | else | |
83 | return AArch64II::MO_GOT; | |
84 | } | |
970d7e83 | 85 | |
1a4d82fc JJ |
86 | // If symbol visibility is hidden, the extra load is not needed if |
87 | // the symbol is definitely defined in the current translation unit. | |
970d7e83 | 88 | |
1a4d82fc JJ |
89 | // The handling of non-hidden symbols in PIC mode is rather target-dependent: |
90 | // + On MachO, if the symbol is defined in this module the GOT can be | |
91 | // skipped. | |
92 | // + On ELF, the R_AARCH64_COPY relocation means that even symbols actually | |
93 | // defined could end up in unexpected places. Use a GOT. | |
94 | if (TM.getRelocationModel() != Reloc::Static && GV->hasDefaultVisibility()) { | |
95 | if (isTargetMachO()) | |
96 | return (isDecl || GV->isWeakForLinker()) ? AArch64II::MO_GOT | |
97 | : AArch64II::MO_NO_FLAG; | |
98 | else | |
99 | // No need to go through the GOT for local symbols on ELF. | |
100 | return GV->hasLocalLinkage() ? AArch64II::MO_NO_FLAG : AArch64II::MO_GOT; | |
101 | } | |
102 | ||
103 | return AArch64II::MO_NO_FLAG; | |
970d7e83 LB |
104 | } |
105 | ||
1a4d82fc JJ |
106 | /// This function returns the name of a function which has an interface |
107 | /// like the non-standard bzero function, if such a function exists on | |
108 | /// the current subtarget and it is considered prefereable over | |
109 | /// memset with zero passed as the second argument. Otherwise it | |
110 | /// returns null. | |
111 | const char *AArch64Subtarget::getBZeroEntry() const { | |
112 | // Prefer bzero on Darwin only. | |
113 | if(isTargetDarwin()) | |
114 | return "bzero"; | |
115 | ||
116 | return nullptr; | |
117 | } | |
118 | ||
119 | void AArch64Subtarget::overrideSchedPolicy(MachineSchedPolicy &Policy, | |
120 | MachineInstr *begin, MachineInstr *end, | |
121 | unsigned NumRegionInstrs) const { | |
122 | // LNT run (at least on Cyclone) showed reasonably significant gains for | |
123 | // bi-directional scheduling. 253.perlbmk. | |
124 | Policy.OnlyTopDown = false; | |
125 | Policy.OnlyBottomUp = false; | |
126 | } | |
970d7e83 | 127 | |
1a4d82fc JJ |
128 | bool AArch64Subtarget::enableEarlyIfConversion() const { |
129 | return EnableEarlyIfConvert; | |
970d7e83 | 130 | } |
85aaf69f SL |
131 | |
132 | std::unique_ptr<PBQPRAConstraint> | |
133 | AArch64Subtarget::getCustomPBQPConstraints() const { | |
134 | if (!isCortexA57()) | |
135 | return nullptr; | |
136 | ||
137 | return llvm::make_unique<A57ChainingConstraint>(); | |
138 | } |