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
21using namespace llvm;
22
23#define DEBUG_TYPE "mips-os16"
24
25static cl::opt<std::string> Mips32FunctionMask(
26 "mips32-function-mask",
27 cl::init(Val: ""),
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 point
48// registers because of the ABI
49//
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 operations
73//
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>(Val&: I)) {
99 LLVM_DEBUG(dbgs() << "Working on call"
100 << "\n");
101 Function &F_ = *CI->getCalledFunction();
102 if (needsFPFromSig(F&: 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 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(Kind: "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(Kind: "nomips16");
149 }
150 else {
151 LLVM_DEBUG(dbgs() << "os16 forced mips16: " << F.getName() << "\n");
152 F.addFnAttr(Kind: "mips16");
153 }
154 }
155 }
156
157 return modified;
158}
159
160ModulePass *llvm::createMipsOs16Pass() { return new MipsOs16(); }
161