MipsSubtarget.cpp revision a430cb613b6e93c05f128b04323c57acfd08686d 
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
44void MipsSubtarget::anchor() { }
45
46MipsSubtarget::MipsSubtarget(const std::string &TT, const std::string &CPU,
47                             const std::string &FS, bool little,
48                             Reloc::Model _RM, MipsTargetMachine *_TM) :
49  MipsGenSubtargetInfo(TT, CPU, FS),
50  MipsArchVersion(Mips32), MipsABI(UnknownABI), IsLittle(little),
51  IsSingleFloat(false), IsFP64bit(false), IsGP64bit(false), HasVFPU(false),
52  IsLinux(true), HasSEInReg(false), HasCondMov(false), HasSwap(false),
53  HasBitCount(false), HasFPIdx(false),
54  InMips16Mode(false), InMicroMipsMode(false), HasDSP(false), HasDSPR2(false),
55  AllowMixed16_32(Mixed16_32),
56  RM(_RM), OverrideMode(NoOverride), TM(_TM)
57{
58  std::string CPUName = CPU;
59  if (CPUName.empty())
60    CPUName = "mips32";
61
62  // Parse features string.
63  ParseSubtargetFeatures(CPUName, FS);
64
65  PreviousInMips16Mode = InMips16Mode;
66
67  // Initialize scheduling itinerary for the specified CPU.
68  InstrItins = getInstrItineraryForCPU(CPUName);
69
70  // Set MipsABI if it hasn't been set yet.
71  if (MipsABI == UnknownABI)
72    MipsABI = hasMips64() ? N64 : O32;
73
74  // Check if Architecture and ABI are compatible.
75  assert(((!hasMips64() && (isABI_O32() || isABI_EABI())) ||
76          (hasMips64() && (isABI_N32() || isABI_N64()))) &&
77         "Invalid  Arch & ABI pair.");
78
79  // Is the target system Linux ?
80  if (TT.find("linux") == std::string::npos)
81    IsLinux = false;
82
83  // Set UseSmallSection.
84  UseSmallSection = !IsLinux && (RM == Reloc::Static);
85}
86
87bool
88MipsSubtarget::enablePostRAScheduler(CodeGenOpt::Level OptLevel,
89                                    TargetSubtargetInfo::AntiDepBreakMode &Mode,
90                                     RegClassVector &CriticalPathRCs) const {
91  Mode = TargetSubtargetInfo::ANTIDEP_NONE;
92  CriticalPathRCs.clear();
93  CriticalPathRCs.push_back(hasMips64() ?
94                            &Mips::CPU64RegsRegClass : &Mips::CPURegsRegClass);
95  return OptLevel >= CodeGenOpt::Aggressive;
96}
97
98//FIXME: This logic for reseting the subtarget along with
99// the helper classes can probably be simplified but there are a lot of
100// cases so we will defer rewriting this to later.
101//
102void MipsSubtarget::resetSubtarget(MachineFunction *MF) {
103  bool ChangeToMips16 = false, ChangeToNoMips16 = false;
104  DEBUG(dbgs() << "resetSubtargetFeatures" << "\n");
105  AttributeSet FnAttrs = MF->getFunction()->getAttributes();
106  ChangeToMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
107                                        "mips16");
108  ChangeToNoMips16 = FnAttrs.hasAttribute(AttributeSet::FunctionIndex,
109                                        "nomips16");
110  assert (!(ChangeToMips16 & ChangeToNoMips16) &&
111          "mips16 and nomips16 specified on the same function");
112  if (ChangeToMips16) {
113    if (PreviousInMips16Mode)
114      return;
115    OverrideMode = Mips16Override;
116    PreviousInMips16Mode = true;
117    TM->setHelperClassesMips16();
118    return;
119  } else if (ChangeToNoMips16) {
120    if (!PreviousInMips16Mode)
121      return;
122    OverrideMode = NoMips16Override;
123    PreviousInMips16Mode = false;
124    TM->setHelperClassesMipsSE();
125    return;
126  } else {
127    if (OverrideMode == NoOverride)
128      return;
129    OverrideMode = NoOverride;
130    DEBUG(dbgs() << "back to default" << "\n");
131    if (inMips16Mode() && !PreviousInMips16Mode) {
132      TM->setHelperClassesMips16();
133      PreviousInMips16Mode = true;
134    } else if (!inMips16Mode() && PreviousInMips16Mode) {
135      TM->setHelperClassesMipsSE();
136      PreviousInMips16Mode = false;
137    }
138    return;
139  }
140}
141
142