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      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 #define DEBUG_TYPE "mips-os16"
     15 #include "MipsOs16.h"
     16 #include "llvm/IR/Module.h"
     17 #include "llvm/Support/Debug.h"
     18 #include "llvm/Support/raw_ostream.h"
     19 
     20 namespace {
     21 
     22   // Figure out if we need float point based on the function signature.
     23   // We need to move variables in and/or out of floating point
     24   // registers because of the ABI
     25   //
     26   bool needsFPFromSig(Function &F) {
     27     Type* RetType = F.getReturnType();
     28     switch (RetType->getTypeID()) {
     29     case Type::FloatTyID:
     30     case Type::DoubleTyID:
     31       return true;
     32     default:
     33       ;
     34     }
     35     if (F.arg_size() >=1) {
     36       Argument &Arg = F.getArgumentList().front();
     37       switch (Arg.getType()->getTypeID()) {
     38         case Type::FloatTyID:
     39         case Type::DoubleTyID:
     40           return true;
     41         default:
     42           ;
     43       }
     44     }
     45     return false;
     46   }
     47 
     48   // Figure out if the function will need floating point operations
     49   //
     50   bool needsFP(Function &F) {
     51     if (needsFPFromSig(F))
     52       return true;
     53     for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
     54       for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
     55          I != E; ++I) {
     56         const Instruction &Inst = *I;
     57         switch (Inst.getOpcode()) {
     58         case Instruction::FAdd:
     59         case Instruction::FSub:
     60         case Instruction::FMul:
     61         case Instruction::FDiv:
     62         case Instruction::FRem:
     63         case Instruction::FPToUI:
     64         case Instruction::FPToSI:
     65         case Instruction::UIToFP:
     66         case Instruction::SIToFP:
     67         case Instruction::FPTrunc:
     68         case Instruction::FPExt:
     69         case Instruction::FCmp:
     70           return true;
     71         default:
     72           ;
     73         }
     74         if (const CallInst *CI = dyn_cast<CallInst>(I)) {
     75           DEBUG(dbgs() << "Working on call" << "\n");
     76           Function &F_ =  *CI->getCalledFunction();
     77           if (needsFPFromSig(F_))
     78             return true;
     79         }
     80       }
     81     return false;
     82   }
     83 }
     84 namespace llvm {
     85 
     86 
     87 bool MipsOs16::runOnModule(Module &M) {
     88   DEBUG(errs() << "Run on Module MipsOs16\n");
     89   bool modified = false;
     90   for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
     91     if (F->isDeclaration()) continue;
     92     DEBUG(dbgs() << "Working on " << F->getName() << "\n");
     93     if (needsFP(*F)) {
     94       DEBUG(dbgs() << " need to compile as nomips16 \n");
     95       F->addFnAttr("nomips16");
     96     }
     97     else {
     98       F->addFnAttr("mips16");
     99       DEBUG(dbgs() << " no need to compile as nomips16 \n");
    100     }
    101   }
    102   return modified;
    103 }
    104 
    105 char MipsOs16::ID = 0;
    106 
    107 }
    108 
    109 ModulePass *llvm::createMipsOs16(MipsTargetMachine &TM) {
    110   return new MipsOs16;
    111 }
    112 
    113 
    114