1 //===---- MipsOs16.cpp for Mips Option -Os16 --------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines an optimization phase for the MIPS target. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "Mips.h" 14 #include "llvm/IR/Instructions.h" 15 #include "llvm/IR/Module.h" 16 #include "llvm/Pass.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 36 MipsOs16() : ModulePass(ID) {} 37 38 StringRef getPassName() const override { return "MIPS Os16 Optimization"; } 39 40 bool runOnModule(Module &M) override; 41 }; 42 43 char MipsOs16::ID = 0; 44 } 45 46 // Figure out if we need float point based on the function signature. 47 // We need to move variables in and/or out of floating point 48 // registers because of the ABI 49 // 50 static bool needsFPFromSig(Function &F) { 51 Type* RetType = F.getReturnType(); 52 switch (RetType->getTypeID()) { 53 case Type::FloatTyID: 54 case Type::DoubleTyID: 55 return true; 56 default: 57 ; 58 } 59 if (F.arg_size() >=1) { 60 Argument &Arg = *F.arg_begin(); 61 switch (Arg.getType()->getTypeID()) { 62 case Type::FloatTyID: 63 case Type::DoubleTyID: 64 return true; 65 default: 66 ; 67 } 68 } 69 return false; 70 } 71 72 // Figure out if the function will need floating point operations 73 // 74 static bool needsFP(Function &F) { 75 if (needsFPFromSig(F)) 76 return true; 77 for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB) 78 for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); 79 I != E; ++I) { 80 const Instruction &Inst = *I; 81 switch (Inst.getOpcode()) { 82 case Instruction::FAdd: 83 case Instruction::FSub: 84 case Instruction::FMul: 85 case Instruction::FDiv: 86 case Instruction::FRem: 87 case Instruction::FPToUI: 88 case Instruction::FPToSI: 89 case Instruction::UIToFP: 90 case Instruction::SIToFP: 91 case Instruction::FPTrunc: 92 case Instruction::FPExt: 93 case Instruction::FCmp: 94 return true; 95 default: 96 ; 97 } 98 if (const CallInst *CI = dyn_cast<CallInst>(I)) { 99 LLVM_DEBUG(dbgs() << "Working on call" 100 << "\n"); 101 Function &F_ = *CI->getCalledFunction(); 102 if (needsFPFromSig(F_)) 103 return true; 104 } 105 } 106 return false; 107 } 108 109 110 bool MipsOs16::runOnModule(Module &M) { 111 bool usingMask = Mips32FunctionMask.length() > 0; 112 bool doneUsingMask = false; // this will make it stop repeating 113 114 LLVM_DEBUG(dbgs() << "Run on Module MipsOs16 \n" 115 << Mips32FunctionMask << "\n"); 116 if (usingMask) 117 LLVM_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 LLVM_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 LLVM_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 LLVM_DEBUG(dbgs() << "os16 forced mips32: " << F.getName() << "\n"); 148 F.addFnAttr("nomips16"); 149 } 150 else { 151 LLVM_DEBUG(dbgs() << "os16 forced mips16: " << F.getName() << "\n"); 152 F.addFnAttr("mips16"); 153 } 154 } 155 } 156 157 return modified; 158 } 159 160 ModulePass *llvm::createMipsOs16Pass() { return new MipsOs16(); } 161