1 //===-- MipsTargetMachine.cpp - Define TargetMachine for Mips -------------===//
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 // Implements the info about Mips target spec.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "MipsTargetMachine.h"
15 #include "Mips.h"
16 #include "Mips16FrameLowering.h"
17 #include "Mips16ISelDAGToDAG.h"
18 #include "Mips16ISelLowering.h"
19 #include "Mips16InstrInfo.h"
20 #include "MipsFrameLowering.h"
21 #include "MipsInstrInfo.h"
22 #include "MipsSEFrameLowering.h"
23 #include "MipsSEISelDAGToDAG.h"
24 #include "MipsSEISelLowering.h"
25 #include "MipsSEInstrInfo.h"
26 #include "MipsTargetObjectFile.h"
27 #include "llvm/Analysis/TargetTransformInfo.h"
28 #include "llvm/CodeGen/Passes.h"
29 #include "llvm/IR/LegacyPassManager.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Support/TargetRegistry.h"
32 #include "llvm/Support/raw_ostream.h"
33 #include "llvm/Transforms/Scalar.h"
34
35 using namespace llvm;
36
37 #define DEBUG_TYPE "mips"
38
LLVMInitializeMipsTarget()39 extern "C" void LLVMInitializeMipsTarget() {
40 // Register the target.
41 RegisterTargetMachine<MipsebTargetMachine> X(TheMipsTarget);
42 RegisterTargetMachine<MipselTargetMachine> Y(TheMipselTarget);
43 RegisterTargetMachine<MipsebTargetMachine> A(TheMips64Target);
44 RegisterTargetMachine<MipselTargetMachine> B(TheMips64elTarget);
45 }
46
computeDataLayout(const Triple & TT,StringRef CPU,const TargetOptions & Options,bool isLittle)47 static std::string computeDataLayout(const Triple &TT, StringRef CPU,
48 const TargetOptions &Options,
49 bool isLittle) {
50 std::string Ret = "";
51 MipsABIInfo ABI = MipsABIInfo::computeTargetABI(TT, CPU, Options.MCOptions);
52
53 // There are both little and big endian mips.
54 if (isLittle)
55 Ret += "e";
56 else
57 Ret += "E";
58
59 Ret += "-m:m";
60
61 // Pointers are 32 bit on some ABIs.
62 if (!ABI.IsN64())
63 Ret += "-p:32:32";
64
65 // 8 and 16 bit integers only need to have natural alignment, but try to
66 // align them to 32 bits. 64 bit integers have natural alignment.
67 Ret += "-i8:8:32-i16:16:32-i64:64";
68
69 // 32 bit registers are always available and the stack is at least 64 bit
70 // aligned. On N64 64 bit registers are also available and the stack is
71 // 128 bit aligned.
72 if (ABI.IsN64() || ABI.IsN32())
73 Ret += "-n32:64-S128";
74 else
75 Ret += "-n32-S64";
76
77 return Ret;
78 }
79
80 // On function prologue, the stack is created by decrementing
81 // its pointer. Once decremented, all references are done with positive
82 // offset from the stack/frame pointer, using StackGrowsUp enables
83 // an easier handling.
84 // Using CodeModel::Large enables different CALL behavior.
MipsTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL,bool isLittle)85 MipsTargetMachine::MipsTargetMachine(const Target &T, const Triple &TT,
86 StringRef CPU, StringRef FS,
87 const TargetOptions &Options,
88 Reloc::Model RM, CodeModel::Model CM,
89 CodeGenOpt::Level OL, bool isLittle)
90 : LLVMTargetMachine(T, computeDataLayout(TT, CPU, Options, isLittle), TT,
91 CPU, FS, Options, RM, CM, OL),
92 isLittle(isLittle), TLOF(make_unique<MipsTargetObjectFile>()),
93 ABI(MipsABIInfo::computeTargetABI(TT, CPU, Options.MCOptions)),
94 Subtarget(nullptr), DefaultSubtarget(TT, CPU, FS, isLittle, *this),
95 NoMips16Subtarget(TT, CPU, FS.empty() ? "-mips16" : FS.str() + ",-mips16",
96 isLittle, *this),
97 Mips16Subtarget(TT, CPU, FS.empty() ? "+mips16" : FS.str() + ",+mips16",
98 isLittle, *this) {
99 Subtarget = &DefaultSubtarget;
100 initAsmInfo();
101 }
102
~MipsTargetMachine()103 MipsTargetMachine::~MipsTargetMachine() {}
104
anchor()105 void MipsebTargetMachine::anchor() { }
106
MipsebTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL)107 MipsebTargetMachine::MipsebTargetMachine(const Target &T, const Triple &TT,
108 StringRef CPU, StringRef FS,
109 const TargetOptions &Options,
110 Reloc::Model RM, CodeModel::Model CM,
111 CodeGenOpt::Level OL)
112 : MipsTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, false) {}
113
anchor()114 void MipselTargetMachine::anchor() { }
115
MipselTargetMachine(const Target & T,const Triple & TT,StringRef CPU,StringRef FS,const TargetOptions & Options,Reloc::Model RM,CodeModel::Model CM,CodeGenOpt::Level OL)116 MipselTargetMachine::MipselTargetMachine(const Target &T, const Triple &TT,
117 StringRef CPU, StringRef FS,
118 const TargetOptions &Options,
119 Reloc::Model RM, CodeModel::Model CM,
120 CodeGenOpt::Level OL)
121 : MipsTargetMachine(T, TT, CPU, FS, Options, RM, CM, OL, true) {}
122
123 const MipsSubtarget *
getSubtargetImpl(const Function & F) const124 MipsTargetMachine::getSubtargetImpl(const Function &F) const {
125 Attribute CPUAttr = F.getFnAttribute("target-cpu");
126 Attribute FSAttr = F.getFnAttribute("target-features");
127
128 std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
129 ? CPUAttr.getValueAsString().str()
130 : TargetCPU;
131 std::string FS = !FSAttr.hasAttribute(Attribute::None)
132 ? FSAttr.getValueAsString().str()
133 : TargetFS;
134 bool hasMips16Attr =
135 !F.getFnAttribute("mips16").hasAttribute(Attribute::None);
136 bool hasNoMips16Attr =
137 !F.getFnAttribute("nomips16").hasAttribute(Attribute::None);
138
139 // FIXME: This is related to the code below to reset the target options,
140 // we need to know whether or not the soft float flag is set on the
141 // function, so we can enable it as a subtarget feature.
142 bool softFloat =
143 F.hasFnAttribute("use-soft-float") &&
144 F.getFnAttribute("use-soft-float").getValueAsString() == "true";
145
146 if (hasMips16Attr)
147 FS += FS.empty() ? "+mips16" : ",+mips16";
148 else if (hasNoMips16Attr)
149 FS += FS.empty() ? "-mips16" : ",-mips16";
150 if (softFloat)
151 FS += FS.empty() ? "+soft-float" : ",+soft-float";
152
153 auto &I = SubtargetMap[CPU + FS];
154 if (!I) {
155 // This needs to be done before we create a new subtarget since any
156 // creation will depend on the TM and the code generation flags on the
157 // function that reside in TargetOptions.
158 resetTargetOptions(F);
159 I = llvm::make_unique<MipsSubtarget>(TargetTriple, CPU, FS, isLittle,
160 *this);
161 }
162 return I.get();
163 }
164
resetSubtarget(MachineFunction * MF)165 void MipsTargetMachine::resetSubtarget(MachineFunction *MF) {
166 DEBUG(dbgs() << "resetSubtarget\n");
167
168 Subtarget = const_cast<MipsSubtarget *>(getSubtargetImpl(*MF->getFunction()));
169 MF->setSubtarget(Subtarget);
170 return;
171 }
172
173 namespace {
174 /// Mips Code Generator Pass Configuration Options.
175 class MipsPassConfig : public TargetPassConfig {
176 public:
MipsPassConfig(MipsTargetMachine * TM,PassManagerBase & PM)177 MipsPassConfig(MipsTargetMachine *TM, PassManagerBase &PM)
178 : TargetPassConfig(TM, PM) {
179 // The current implementation of long branch pass requires a scratch
180 // register ($at) to be available before branch instructions. Tail merging
181 // can break this requirement, so disable it when long branch pass is
182 // enabled.
183 EnableTailMerge = !getMipsSubtarget().enableLongBranchPass();
184 }
185
getMipsTargetMachine() const186 MipsTargetMachine &getMipsTargetMachine() const {
187 return getTM<MipsTargetMachine>();
188 }
189
getMipsSubtarget() const190 const MipsSubtarget &getMipsSubtarget() const {
191 return *getMipsTargetMachine().getSubtargetImpl();
192 }
193
194 void addIRPasses() override;
195 bool addInstSelector() override;
196 void addMachineSSAOptimization() override;
197 void addPreEmitPass() override;
198
199 void addPreRegAlloc() override;
200
201 };
202 } // namespace
203
createPassConfig(PassManagerBase & PM)204 TargetPassConfig *MipsTargetMachine::createPassConfig(PassManagerBase &PM) {
205 return new MipsPassConfig(this, PM);
206 }
207
addIRPasses()208 void MipsPassConfig::addIRPasses() {
209 TargetPassConfig::addIRPasses();
210 addPass(createAtomicExpandPass(&getMipsTargetMachine()));
211 if (getMipsSubtarget().os16())
212 addPass(createMipsOs16Pass(getMipsTargetMachine()));
213 if (getMipsSubtarget().inMips16HardFloat())
214 addPass(createMips16HardFloatPass(getMipsTargetMachine()));
215 }
216 // Install an instruction selector pass using
217 // the ISelDag to gen Mips code.
addInstSelector()218 bool MipsPassConfig::addInstSelector() {
219 addPass(createMipsModuleISelDagPass(getMipsTargetMachine()));
220 addPass(createMips16ISelDag(getMipsTargetMachine()));
221 addPass(createMipsSEISelDag(getMipsTargetMachine()));
222 return false;
223 }
224
addMachineSSAOptimization()225 void MipsPassConfig::addMachineSSAOptimization() {
226 addPass(createMipsOptimizePICCallPass(getMipsTargetMachine()));
227 TargetPassConfig::addMachineSSAOptimization();
228 }
229
addPreRegAlloc()230 void MipsPassConfig::addPreRegAlloc() {
231 if (getOptLevel() == CodeGenOpt::None)
232 addPass(createMipsOptimizePICCallPass(getMipsTargetMachine()));
233 }
234
getTargetIRAnalysis()235 TargetIRAnalysis MipsTargetMachine::getTargetIRAnalysis() {
236 return TargetIRAnalysis([this](const Function &F) {
237 if (Subtarget->allowMixed16_32()) {
238 DEBUG(errs() << "No Target Transform Info Pass Added\n");
239 // FIXME: This is no longer necessary as the TTI returned is per-function.
240 return TargetTransformInfo(F.getParent()->getDataLayout());
241 }
242
243 DEBUG(errs() << "Target Transform Info Pass Added\n");
244 return TargetTransformInfo(BasicTTIImpl(this, F));
245 });
246 }
247
248 // Implemented by targets that want to run passes immediately before
249 // machine code is emitted. return true if -print-machineinstrs should
250 // print out the code after the passes.
addPreEmitPass()251 void MipsPassConfig::addPreEmitPass() {
252 MipsTargetMachine &TM = getMipsTargetMachine();
253 addPass(createMipsDelaySlotFillerPass(TM));
254 addPass(createMipsLongBranchPass(TM));
255 addPass(createMipsConstantIslandPass(TM));
256 }
257