• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 //===---- MipsOs16.cpp for Mips Option -Os16                       --------===//
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 defines an optimization phase for the MIPS target.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/IR/Instructions.h"
15 #include "Mips.h"
16 #include "llvm/IR/Module.h"
17 #include "llvm/Support/CommandLine.h"
18 #include "llvm/Support/Debug.h"
19 #include "llvm/Support/raw_ostream.h"
20 
21 using namespace llvm;
22 
23 #define DEBUG_TYPE "mips-os16"
24 
25 static cl::opt<std::string> Mips32FunctionMask(
26   "mips32-function-mask",
27   cl::init(""),
28   cl::desc("Force function to be mips32"),
29   cl::Hidden);
30 
31 namespace {
32   class MipsOs16 : public ModulePass {
33   public:
34     static char ID;
35 
MipsOs16()36     MipsOs16() : ModulePass(ID) {}
37 
getPassName() const38     const char *getPassName() const override {
39       return "MIPS Os16 Optimization";
40     }
41 
42     bool runOnModule(Module &M) override;
43   };
44 
45   char MipsOs16::ID = 0;
46 }
47 
48 // Figure out if we need float point based on the function signature.
49 // We need to move variables in and/or out of floating point
50 // registers because of the ABI
51 //
needsFPFromSig(Function & F)52 static  bool needsFPFromSig(Function &F) {
53   Type* RetType = F.getReturnType();
54   switch (RetType->getTypeID()) {
55   case Type::FloatTyID:
56   case Type::DoubleTyID:
57     return true;
58   default:
59     ;
60   }
61   if (F.arg_size() >=1) {
62     Argument &Arg = F.getArgumentList().front();
63     switch (Arg.getType()->getTypeID()) {
64     case Type::FloatTyID:
65     case Type::DoubleTyID:
66       return true;
67     default:
68       ;
69     }
70   }
71   return false;
72 }
73 
74 // Figure out if the function will need floating point operations
75 //
needsFP(Function & F)76 static bool needsFP(Function &F) {
77   if (needsFPFromSig(F))
78     return true;
79   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
80     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
81          I != E; ++I) {
82       const Instruction &Inst = *I;
83       switch (Inst.getOpcode()) {
84       case Instruction::FAdd:
85       case Instruction::FSub:
86       case Instruction::FMul:
87       case Instruction::FDiv:
88       case Instruction::FRem:
89       case Instruction::FPToUI:
90       case Instruction::FPToSI:
91       case Instruction::UIToFP:
92       case Instruction::SIToFP:
93       case Instruction::FPTrunc:
94       case Instruction::FPExt:
95       case Instruction::FCmp:
96         return true;
97       default:
98         ;
99       }
100       if (const CallInst *CI = dyn_cast<CallInst>(I)) {
101         DEBUG(dbgs() << "Working on call" << "\n");
102         Function &F_ =  *CI->getCalledFunction();
103         if (needsFPFromSig(F_))
104           return true;
105       }
106     }
107   return false;
108 }
109 
110 
runOnModule(Module & M)111 bool MipsOs16::runOnModule(Module &M) {
112   bool usingMask = Mips32FunctionMask.length() > 0;
113   bool doneUsingMask = false; // this will make it stop repeating
114 
115   DEBUG(dbgs() << "Run on Module MipsOs16 \n" << Mips32FunctionMask << "\n");
116   if (usingMask)
117     DEBUG(dbgs() << "using mask \n" << Mips32FunctionMask << "\n");
118 
119   unsigned int functionIndex = 0;
120   bool modified = false;
121 
122   for (auto &F : M) {
123     if (F.isDeclaration())
124       continue;
125 
126     DEBUG(dbgs() << "Working on " << F.getName() << "\n");
127     if (usingMask) {
128       if (!doneUsingMask) {
129         if (functionIndex == Mips32FunctionMask.length())
130           functionIndex = 0;
131         switch (Mips32FunctionMask[functionIndex]) {
132         case '1':
133           DEBUG(dbgs() << "mask forced mips32: " << F.getName() << "\n");
134           F.addFnAttr("nomips16");
135           break;
136         case '.':
137           doneUsingMask = true;
138           break;
139         default:
140           break;
141         }
142         functionIndex++;
143       }
144     }
145     else {
146       if (needsFP(F)) {
147         DEBUG(dbgs() << "os16 forced mips32: " << F.getName() << "\n");
148         F.addFnAttr("nomips16");
149       }
150       else {
151         DEBUG(dbgs() << "os16 forced mips16: " << F.getName() << "\n");
152         F.addFnAttr("mips16");
153       }
154     }
155   }
156 
157   return modified;
158 }
159 
createMipsOs16Pass(MipsTargetMachine & TM)160 ModulePass *llvm::createMipsOs16Pass(MipsTargetMachine &TM) {
161   return new MipsOs16;
162 }
163