MipsOs16.cpp revision 6febf857f690665bc33b84c957cdefb39a27f63d 
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/CommandLine.h"
18#include "llvm/Support/Debug.h"
19#include "llvm/Support/raw_ostream.h"
20
21
22static cl::opt<std::string> Mips32FunctionMask(
23  "mips32-function-mask",
24  cl::init(""),
25  cl::desc("Force function to be mips32"),
26  cl::Hidden);
27
28namespace {
29
30  // Figure out if we need float point based on the function signature.
31  // We need to move variables in and/or out of floating point
32  // registers because of the ABI
33  //
34  bool needsFPFromSig(Function &F) {
35    Type* RetType = F.getReturnType();
36    switch (RetType->getTypeID()) {
37    case Type::FloatTyID:
38    case Type::DoubleTyID:
39      return true;
40    default:
41      ;
42    }
43    if (F.arg_size() >=1) {
44      Argument &Arg = F.getArgumentList().front();
45      switch (Arg.getType()->getTypeID()) {
46        case Type::FloatTyID:
47        case Type::DoubleTyID:
48          return true;
49        default:
50          ;
51      }
52    }
53    return false;
54  }
55
56  // Figure out if the function will need floating point operations
57  //
58  bool needsFP(Function &F) {
59    if (needsFPFromSig(F))
60      return true;
61    for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
62      for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
63         I != E; ++I) {
64        const Instruction &Inst = *I;
65        switch (Inst.getOpcode()) {
66        case Instruction::FAdd:
67        case Instruction::FSub:
68        case Instruction::FMul:
69        case Instruction::FDiv:
70        case Instruction::FRem:
71        case Instruction::FPToUI:
72        case Instruction::FPToSI:
73        case Instruction::UIToFP:
74        case Instruction::SIToFP:
75        case Instruction::FPTrunc:
76        case Instruction::FPExt:
77        case Instruction::FCmp:
78          return true;
79        default:
80          ;
81        }
82        if (const CallInst *CI = dyn_cast<CallInst>(I)) {
83          DEBUG(dbgs() << "Working on call" << "\n");
84          Function &F_ =  *CI->getCalledFunction();
85          if (needsFPFromSig(F_))
86            return true;
87        }
88      }
89    return false;
90  }
91}
92namespace llvm {
93
94
95bool MipsOs16::runOnModule(Module &M) {
96  bool usingMask = Mips32FunctionMask.length() > 0;
97  DEBUG(dbgs() << "Run on Module MipsOs16 \n" << Mips32FunctionMask << "\n");
98  if (usingMask)
99    DEBUG(dbgs() << "using mask \n" << Mips32FunctionMask << "\n");
100  unsigned int functionIndex = 0;
101  bool modified = false;
102  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
103    if (F->isDeclaration()) continue;
104    DEBUG(dbgs() << "Working on " << F->getName() << "\n");
105    if (usingMask) {
106      if (functionIndex == Mips32FunctionMask.length())
107        functionIndex = 0;
108      if (Mips32FunctionMask[functionIndex] == '1') {
109        DEBUG(dbgs() << "mask forced mips32: " << F->getName() << "\n");
110        F->addFnAttr("nomips16");
111      }
112      functionIndex++;
113    }
114    else {
115      if (needsFP(*F)) {
116        DEBUG(dbgs() << "os16 forced mips32: " << F->getName() << "\n");
117        F->addFnAttr("nomips16");
118      }
119      else {
120        DEBUG(dbgs() << "os16 forced mips16: " << F->getName() << "\n");
121        F->addFnAttr("mips16");
122      }
123    }
124  }
125  return modified;
126}
127
128char MipsOs16::ID = 0;
129
130}
131
132ModulePass *llvm::createMipsOs16(MipsTargetMachine &TM) {
133  return new MipsOs16;
134}
135
136
137