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
33using namespace llvm;
34
35// FIXME: Maybe this should be on by default when Mips16 is specified
36//
37static 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
44static 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
51static cl::opt<bool>
52Mips16HardFloat("mips16-hard-float", cl::NotHidden,
53                cl::desc("MIPS: mips16 hard float enable."),
54                cl::init(false));
55
56static cl::opt<bool>
57Mips16ConstantIslands(
58  "mips16-constant-islands", cl::Hidden,
59  cl::desc("MIPS: mips16 constant islands enable. experimental feature"),
60  cl::init(false));
61
62void MipsSubtarget::anchor() { }
63
64MipsSubtarget::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
114bool
115MipsSubtarget::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//
129void 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
169bool MipsSubtarget::mipsSEUsesSoftFloat() const {
170  return TM->Options.UseSoftFloat && !InMips16HardFloat;
171}
172
173bool MipsSubtarget::useConstantIslands() {
174  DEBUG(dbgs() << "use constant islands " << Mips16ConstantIslands << "\n");
175  return Mips16ConstantIslands;
176}
177