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   DEBUG(dbgs() << "Run on Module MipsOs16 \n" << Mips32FunctionMask << "\n");
115   if (usingMask)
116     DEBUG(dbgs() << "using mask \n" << Mips32FunctionMask << "\n");
117   unsigned int functionIndex = 0;
118   bool modified = false;
119   for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
120     if (F->isDeclaration()) continue;
121     DEBUG(dbgs() << "Working on " << F->getName() << "\n");
122     if (usingMask) {
123       if (!doneUsingMask) {
124         if (functionIndex == Mips32FunctionMask.length())
125           functionIndex = 0;
126         switch (Mips32FunctionMask[functionIndex]) {
127         case '1':
128           DEBUG(dbgs() << "mask forced mips32: " << F->getName() << "\n");
129           F->addFnAttr("nomips16");
130           break;
131         case '.':
132           doneUsingMask = true;
133           break;
134         default:
135           break;
136         }
137         functionIndex++;
138       }
139     }
140     else {
141       if (needsFP(*F)) {
142         DEBUG(dbgs() << "os16 forced mips32: " << F->getName() << "\n");
143         F->addFnAttr("nomips16");
144       }
145       else {
146         DEBUG(dbgs() << "os16 forced mips16: " << F->getName() << "\n");
147         F->addFnAttr("mips16");
148       }
149     }
150   }
151   return modified;
152 }
153 
createMipsOs16Pass(MipsTargetMachine & TM)154 ModulePass *llvm::createMipsOs16Pass(MipsTargetMachine &TM) {
155   return new MipsOs16;
156 }
157