161 lines · cpp
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-exception6//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 21using namespace llvm;22 23#define DEBUG_TYPE "mips-os16"24 25static cl::opt<std::string> Mips32FunctionMask(26 "mips32-function-mask",27 cl::init(""),28 cl::desc("Force function to be mips32"),29 cl::Hidden);30 31namespace {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 point48// registers because of the ABI49//50static 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 operations73//74static 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 110bool MipsOs16::runOnModule(Module &M) {111 bool usingMask = Mips32FunctionMask.length() > 0;112 bool doneUsingMask = false; // this will make it stop repeating113 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 160ModulePass *llvm::createMipsOs16Pass() { return new MipsOs16(); }161