1 //===---- MipsCCState.cpp - CCState with Mips specific extensions ---------===//
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 #include "MipsCCState.h"
10 #include "MipsSubtarget.h"
11 #include "llvm/IR/Module.h"
12 
13 using namespace llvm;
14 
15 /// This function returns true if CallSym is a long double emulation routine.
16 static bool isF128SoftLibCall(const char *CallSym) {
17   const char *const LibCalls[] = {
18       "__addtf3",      "__divtf3",     "__eqtf2",       "__extenddftf2",
19       "__extendsftf2", "__fixtfdi",    "__fixtfsi",     "__fixtfti",
20       "__fixunstfdi",  "__fixunstfsi", "__fixunstfti",  "__floatditf",
21       "__floatsitf",   "__floattitf",  "__floatunditf", "__floatunsitf",
22       "__floatuntitf", "__getf2",      "__gttf2",       "__letf2",
23       "__lttf2",       "__multf3",     "__netf2",       "__powitf2",
24       "__subtf3",      "__trunctfdf2", "__trunctfsf2",  "__unordtf2",
25       "ceill",         "copysignl",    "cosl",          "exp2l",
26       "expl",          "floorl",       "fmal",          "fmaxl",
27       "fmodl",         "log10l",       "log2l",         "logl",
28       "nearbyintl",    "powl",         "rintl",         "roundl",
29       "sinl",          "sqrtl",        "truncl"};
30 
31   // Check that LibCalls is sorted alphabetically.
32   auto Comp = [](const char *S1, const char *S2) { return strcmp(S1, S2) < 0; };
33   assert(std::is_sorted(std::begin(LibCalls), std::end(LibCalls), Comp));
34   return std::binary_search(std::begin(LibCalls), std::end(LibCalls),
35                             CallSym, Comp);
36 }
37 
38 /// This function returns true if Ty is fp128, {f128} or i128 which was
39 /// originally a fp128.
40 static bool originalTypeIsF128(const Type *Ty, const char *Func) {
41   if (Ty->isFP128Ty())
42     return true;
43 
44   if (Ty->isStructTy() && Ty->getStructNumElements() == 1 &&
45       Ty->getStructElementType(0)->isFP128Ty())
46     return true;
47 
48   // If the Ty is i128 and the function being called is a long double emulation
49   // routine, then the original type is f128.
50   return (Func && Ty->isIntegerTy(128) && isF128SoftLibCall(Func));
51 }
52 
53 /// Return true if the original type was vXfXX.
54 static bool originalEVTTypeIsVectorFloat(EVT Ty) {
55   if (Ty.isVector() && Ty.getVectorElementType().isFloatingPoint())
56     return true;
57 
58   return false;
59 }
60 
61 /// Return true if the original type was vXfXX / vXfXX.
62 static bool originalTypeIsVectorFloat(const Type * Ty) {
63   if (Ty->isVectorTy() && Ty->isFPOrFPVectorTy())
64     return true;
65 
66   return false;
67 }
68 
69 MipsCCState::SpecialCallingConvType
70 MipsCCState::getSpecialCallingConvForCallee(const SDNode *Callee,
71                                             const MipsSubtarget &Subtarget) {
72   MipsCCState::SpecialCallingConvType SpecialCallingConv = NoSpecialCallingConv;
73   if (Subtarget.inMips16HardFloat()) {
74     if (const GlobalAddressSDNode *G =
75             dyn_cast<const GlobalAddressSDNode>(Callee)) {
76       llvm::StringRef Sym = G->getGlobal()->getName();
77       Function *F = G->getGlobal()->getParent()->getFunction(Sym);
78       if (F && F->hasFnAttribute("__Mips16RetHelper")) {
79         SpecialCallingConv = Mips16RetHelperConv;
80       }
81     }
82   }
83   return SpecialCallingConv;
84 }
85 
86 void MipsCCState::PreAnalyzeCallResultForF128(
87     const SmallVectorImpl<ISD::InputArg> &Ins,
88     const Type *RetTy, const char *Call) {
89   for (unsigned i = 0; i < Ins.size(); ++i) {
90     OriginalArgWasF128.push_back(
91         originalTypeIsF128(RetTy, Call));
92     OriginalArgWasFloat.push_back(RetTy->isFloatingPointTy());
93   }
94 }
95 
96 /// Identify lowered values that originated from f128 or float arguments and
97 /// record this for use by RetCC_MipsN.
98 void MipsCCState::PreAnalyzeReturnForF128(
99     const SmallVectorImpl<ISD::OutputArg> &Outs) {
100   const MachineFunction &MF = getMachineFunction();
101   for (unsigned i = 0; i < Outs.size(); ++i) {
102     OriginalArgWasF128.push_back(
103         originalTypeIsF128(MF.getFunction().getReturnType(), nullptr));
104     OriginalArgWasFloat.push_back(
105         MF.getFunction().getReturnType()->isFloatingPointTy());
106   }
107 }
108 
109 /// Identify lower values that originated from vXfXX and record
110 /// this.
111 void MipsCCState::PreAnalyzeCallResultForVectorFloat(
112     const SmallVectorImpl<ISD::InputArg> &Ins, const Type *RetTy) {
113   for (unsigned i = 0; i < Ins.size(); ++i) {
114     OriginalRetWasFloatVector.push_back(originalTypeIsVectorFloat(RetTy));
115   }
116 }
117 
118 /// Identify lowered values that originated from vXfXX arguments and record
119 /// this.
120 void MipsCCState::PreAnalyzeReturnForVectorFloat(
121     const SmallVectorImpl<ISD::OutputArg> &Outs) {
122   for (unsigned i = 0; i < Outs.size(); ++i) {
123     ISD::OutputArg Out = Outs[i];
124     OriginalRetWasFloatVector.push_back(
125         originalEVTTypeIsVectorFloat(Out.ArgVT));
126   }
127 }
128 
129 /// Identify lowered values that originated from f128, float and sret to vXfXX
130 /// arguments and record this.
131 void MipsCCState::PreAnalyzeCallOperands(
132     const SmallVectorImpl<ISD::OutputArg> &Outs,
133     std::vector<TargetLowering::ArgListEntry> &FuncArgs,
134     const char *Func) {
135   for (unsigned i = 0; i < Outs.size(); ++i) {
136     TargetLowering::ArgListEntry FuncArg = FuncArgs[Outs[i].OrigArgIndex];
137 
138     OriginalArgWasF128.push_back(originalTypeIsF128(FuncArg.Ty, Func));
139     OriginalArgWasFloat.push_back(FuncArg.Ty->isFloatingPointTy());
140     OriginalArgWasFloatVector.push_back(FuncArg.Ty->isVectorTy());
141     CallOperandIsFixed.push_back(Outs[i].IsFixed);
142   }
143 }
144 
145 /// Identify lowered values that originated from f128, float and vXfXX arguments
146 /// and record this.
147 void MipsCCState::PreAnalyzeFormalArgumentsForF128(
148     const SmallVectorImpl<ISD::InputArg> &Ins) {
149   const MachineFunction &MF = getMachineFunction();
150   for (unsigned i = 0; i < Ins.size(); ++i) {
151     Function::const_arg_iterator FuncArg = MF.getFunction().arg_begin();
152 
153     // SRet arguments cannot originate from f128 or {f128} returns so we just
154     // push false. We have to handle this specially since SRet arguments
155     // aren't mapped to an original argument.
156     if (Ins[i].Flags.isSRet()) {
157       OriginalArgWasF128.push_back(false);
158       OriginalArgWasFloat.push_back(false);
159       OriginalArgWasFloatVector.push_back(false);
160       continue;
161     }
162 
163     assert(Ins[i].getOrigArgIndex() < MF.getFunction().arg_size());
164     std::advance(FuncArg, Ins[i].getOrigArgIndex());
165 
166     OriginalArgWasF128.push_back(
167         originalTypeIsF128(FuncArg->getType(), nullptr));
168     OriginalArgWasFloat.push_back(FuncArg->getType()->isFloatingPointTy());
169 
170     // The MIPS vector ABI exhibits a corner case of sorts or quirk; if the
171     // first argument is actually an SRet pointer to a vector, then the next
172     // argument slot is $a2.
173     OriginalArgWasFloatVector.push_back(FuncArg->getType()->isVectorTy());
174   }
175 }
176