1 //===-- MipsSubtarget.cpp - Mips Subtarget Information --------------------===//
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 //
10 // This file implements the Mips specific subclass of TargetSubtargetInfo.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #define DEBUG_TYPE "mips-subtarget"
15
16 #include "MipsMachineFunction.h"
17 #include "MipsSubtarget.h"
18 #include "MipsTargetMachine.h"
19 #include "Mips.h"
20 #include "MipsRegisterInfo.h"
21 #include "llvm/IR/Attributes.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/Debug.h"
25 #include "llvm/Support/TargetRegistry.h"
26 #include "llvm/Support/raw_ostream.h"
27
28 #define GET_SUBTARGETINFO_TARGET_DESC
29 #define GET_SUBTARGETINFO_CTOR
30 #include "MipsGenSubtargetInfo.inc"
31
32
33 using namespace llvm;
34
35 // FIXME: Maybe this should be on by default when Mips16 is specified
36 //
37 static cl::opt<bool> Mixed16_32(
38 "mips-mixed-16-32",
39 cl::init(false),
40 cl::desc("Allow for a mixture of Mips16 "
41 "and Mips32 code in a single source file"),
42 cl::Hidden);
43
44 static cl::opt<bool> Mips_Os16(
45 "mips-os16",
46 cl::init(false),
47 cl::desc("Compile all functions that don' use "
48 "floating point as Mips 16"),
49 cl::Hidden);
50
51 static cl::opt<bool>
52 Mips16HardFloat("mips16-hard-float", cl::NotHidden,
53 cl::desc("MIPS: mips16 hard float enable."),
54 cl::init(false));
55
56 static cl::opt<bool>
57 Mips16ConstantIslands(
58 "mips16-constant-islands", cl::Hidden,
59 cl::desc("MIPS: mips16 constant islands enable. experimental feature"),
60 cl::init(false));
61
anchor()62 void MipsSubtarget::anchor() { }
63
MipsSubtarget(const std::string & TT,const std::string & CPU,const std::string & FS,bool little,Reloc::Model _RM,MipsTargetMachine * _TM)64 MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
65 const std::string &FS, bool little,
66 Reloc::Model _RM, MipsTargetMachine *_TM) :
67 MipsGenSubtargetInfo(TT, CPU, FS),
68 MipsArchVersion(Mips32), MipsABI(UnknownABI), IsLittle(little),
69 IsSingleFloat(false), IsFP64bit(false), IsGP64bit(false), HasVFPU(false),
70 IsLinux(true), HasSEInReg(false), HasCondMov(false), HasSwap(false),
71 HasBitCount(false), HasFPIdx(false),
72 InMips16Mode(false), InMips16HardFloat(Mips16HardFloat),
73 InMicroMipsMode(false), HasDSP(false), HasDSPR2(false),
74 AllowMixed16_32(Mixed16_32 | Mips_Os16), Os16(Mips_Os16), HasMSA(false),
75 RM(_RM), OverrideMode(NoOverride), TM(_TM)
76 {
77 std::string CPUName = CPU;
78 if (CPUName.empty())
79 CPUName = "mips32";
80
81 // Parse features string.
82 ParseSubtargetFeatures(CPUName, FS);
83
84 PreviousInMips16Mode = InMips16Mode;
85
86 // Initialize scheduling itinerary for the specified CPU.
87 InstrItins = getInstrItineraryForCPU(CPUName);
88
89 // Set MipsABI if it hasn't been set yet.
90 if (MipsABI == UnknownABI)
91 MipsABI = hasMips64() ? N64 : O32;
92
93 // Check if Architecture and ABI are compatible.
94 assert(((!hasMips64() && (isABI_O32() || isABI_EABI())) ||
95 (hasMips64() && (isABI_N32() || isABI_N64()))) &&
96 "Invalid Arch & ABI pair.");
97
98 if (hasMSA() && !isFP64bit())
99 report_fatal_error("MSA requires a 64-bit FPU register file (FR=1 mode). "
100 "See -mattr=+fp64.",
101 false);
102
103 // Is the target system Linux ?
104 if (TT.find("linux") == std::string::npos)
105 IsLinux = false;
106
107 // Set UseSmallSection.
108 UseSmallSection = !IsLinux && (RM == Reloc::Static);
109 // set some subtarget specific features
110 if (inMips16Mode())
111 HasBitCount=false;
112 }
113
114 bool
enablePostRAScheduler(CodeGenOpt::Level OptLevel,TargetSubtargetInfo::AntiDepBreakMode & Mode,RegClassVector & CriticalPathRCs) const115 MipsSubtarget::enablePostRAScheduler(CodeGenOpt::Level OptLevel,
116 TargetSubtargetInfo::AntiDepBreakMode &Mode,
117 RegClassVector &CriticalPathRCs) const {
118 Mode = TargetSubtargetInfo::ANTIDEP_NONE;
119 CriticalPathRCs.clear();
120 CriticalPathRCs.push_back(hasMips64() ?
121 &Mips::GPR64RegClass : &Mips::GPR32RegClass);
122 return OptLevel >= CodeGenOpt::Aggressive;
123 }
124
125 //FIXME: This logic for reseting the subtarget along with
126 // the helper classes can probably be simplified but there are a lot of
127 // cases so we will defer rewriting this to later.
128 //
resetSubtarget(MachineFunction * MF)129 void MipsSubtarget::resetSubtarget(MachineFunction *MF) {
130 bool ChangeToMips16 = false, ChangeToNoMips16 = false;
131 DEBUG(dbgs() << "resetSubtargetFeatures" << "\n");
132 AttributeSet FnAttrs = MF->getFunction()->getAttributes();
133 ChangeToMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
134 "mips16");
135 ChangeToNoMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
136 "nomips16");
137 assert (!(ChangeToMips16 & ChangeToNoMips16) &&
138 "mips16 and nomips16 specified on the same function");
139 if (ChangeToMips16) {
140 if (PreviousInMips16Mode)
141 return;
142 OverrideMode = Mips16Override;
143 PreviousInMips16Mode = true;
144 TM->setHelperClassesMips16();
145 return;
146 } else if (ChangeToNoMips16) {
147 if (!PreviousInMips16Mode)
148 return;
149 OverrideMode = NoMips16Override;
150 PreviousInMips16Mode = false;
151 TM->setHelperClassesMipsSE();
152 return;
153 } else {
154 if (OverrideMode == NoOverride)
155 return;
156 OverrideMode = NoOverride;
157 DEBUG(dbgs() << "back to default" << "\n");
158 if (inMips16Mode() && !PreviousInMips16Mode) {
159 TM->setHelperClassesMips16();
160 PreviousInMips16Mode = true;
161 } else if (!inMips16Mode() && PreviousInMips16Mode) {
162 TM->setHelperClassesMipsSE();
163 PreviousInMips16Mode = false;
164 }
165 return;
166 }
167 }
168
mipsSEUsesSoftFloat() const169 bool MipsSubtarget::mipsSEUsesSoftFloat() const {
170 return TM->Options.UseSoftFloat && !InMips16HardFloat;
171 }
172
useConstantIslands()173 bool MipsSubtarget::useConstantIslands() {
174 DEBUG(dbgs() << "use constant islands " << Mips16ConstantIslands << "\n");
175 return Mips16ConstantIslands;
176 }
177