1 //=- WebAssemblyMachineFunctionInfo.cpp - WebAssembly Machine Function Info -=//
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 /// \file
10 /// This file implements WebAssembly-specific per-machine-function
11 /// information.
12 ///
13 //===----------------------------------------------------------------------===//
14
15 #include "WebAssemblyMachineFunctionInfo.h"
16 #include "MCTargetDesc/WebAssemblyInstPrinter.h"
17 #include "Utils/WebAssemblyTypeUtilities.h"
18 #include "WebAssemblyISelLowering.h"
19 #include "WebAssemblySubtarget.h"
20 #include "llvm/CodeGen/Analysis.h"
21 #include "llvm/CodeGen/WasmEHFuncInfo.h"
22 #include "llvm/Target/TargetMachine.h"
23 using namespace llvm;
24
25 WebAssemblyFunctionInfo::~WebAssemblyFunctionInfo() = default; // anchor.
26
initWARegs(MachineRegisterInfo & MRI)27 void WebAssemblyFunctionInfo::initWARegs(MachineRegisterInfo &MRI) {
28 assert(WARegs.empty());
29 unsigned Reg = UnusedReg;
30 WARegs.resize(MRI.getNumVirtRegs(), Reg);
31 }
32
computeLegalValueVTs(const Function & F,const TargetMachine & TM,Type * Ty,SmallVectorImpl<MVT> & ValueVTs)33 void llvm::computeLegalValueVTs(const Function &F, const TargetMachine &TM,
34 Type *Ty, SmallVectorImpl<MVT> &ValueVTs) {
35 const DataLayout &DL(F.getParent()->getDataLayout());
36 const WebAssemblyTargetLowering &TLI =
37 *TM.getSubtarget<WebAssemblySubtarget>(F).getTargetLowering();
38 SmallVector<EVT, 4> VTs;
39 ComputeValueVTs(TLI, DL, Ty, VTs);
40
41 for (EVT VT : VTs) {
42 unsigned NumRegs = TLI.getNumRegisters(F.getContext(), VT);
43 MVT RegisterVT = TLI.getRegisterType(F.getContext(), VT);
44 for (unsigned I = 0; I != NumRegs; ++I)
45 ValueVTs.push_back(RegisterVT);
46 }
47 }
48
computeSignatureVTs(const FunctionType * Ty,const Function * TargetFunc,const Function & ContextFunc,const TargetMachine & TM,SmallVectorImpl<MVT> & Params,SmallVectorImpl<MVT> & Results)49 void llvm::computeSignatureVTs(const FunctionType *Ty,
50 const Function *TargetFunc,
51 const Function &ContextFunc,
52 const TargetMachine &TM,
53 SmallVectorImpl<MVT> &Params,
54 SmallVectorImpl<MVT> &Results) {
55 computeLegalValueVTs(ContextFunc, TM, Ty->getReturnType(), Results);
56
57 MVT PtrVT = MVT::getIntegerVT(TM.createDataLayout().getPointerSizeInBits());
58 if (Results.size() > 1 &&
59 !TM.getSubtarget<WebAssemblySubtarget>(ContextFunc).hasMultivalue()) {
60 // WebAssembly can't lower returns of multiple values without demoting to
61 // sret unless multivalue is enabled (see
62 // WebAssemblyTargetLowering::CanLowerReturn). So replace multiple return
63 // values with a poitner parameter.
64 Results.clear();
65 Params.push_back(PtrVT);
66 }
67
68 for (auto *Param : Ty->params())
69 computeLegalValueVTs(ContextFunc, TM, Param, Params);
70 if (Ty->isVarArg())
71 Params.push_back(PtrVT);
72
73 // For swiftcc, emit additional swiftself and swifterror parameters
74 // if there aren't. These additional parameters are also passed for caller.
75 // They are necessary to match callee and caller signature for indirect
76 // call.
77
78 if (TargetFunc && TargetFunc->getCallingConv() == CallingConv::Swift) {
79 MVT PtrVT = MVT::getIntegerVT(TM.createDataLayout().getPointerSizeInBits());
80 bool HasSwiftErrorArg = false;
81 bool HasSwiftSelfArg = false;
82 for (const auto &Arg : TargetFunc->args()) {
83 HasSwiftErrorArg |= Arg.hasAttribute(Attribute::SwiftError);
84 HasSwiftSelfArg |= Arg.hasAttribute(Attribute::SwiftSelf);
85 }
86 if (!HasSwiftErrorArg)
87 Params.push_back(PtrVT);
88 if (!HasSwiftSelfArg)
89 Params.push_back(PtrVT);
90 }
91 }
92
valTypesFromMVTs(const ArrayRef<MVT> & In,SmallVectorImpl<wasm::ValType> & Out)93 void llvm::valTypesFromMVTs(const ArrayRef<MVT> &In,
94 SmallVectorImpl<wasm::ValType> &Out) {
95 for (MVT Ty : In)
96 Out.push_back(WebAssembly::toValType(Ty));
97 }
98
99 std::unique_ptr<wasm::WasmSignature>
signatureFromMVTs(const SmallVectorImpl<MVT> & Results,const SmallVectorImpl<MVT> & Params)100 llvm::signatureFromMVTs(const SmallVectorImpl<MVT> &Results,
101 const SmallVectorImpl<MVT> &Params) {
102 auto Sig = std::make_unique<wasm::WasmSignature>();
103 valTypesFromMVTs(Results, Sig->Returns);
104 valTypesFromMVTs(Params, Sig->Params);
105 return Sig;
106 }
107
WebAssemblyFunctionInfo(const llvm::WebAssemblyFunctionInfo & MFI)108 yaml::WebAssemblyFunctionInfo::WebAssemblyFunctionInfo(
109 const llvm::WebAssemblyFunctionInfo &MFI)
110 : CFGStackified(MFI.isCFGStackified()) {
111 auto *EHInfo = MFI.getWasmEHFuncInfo();
112 const llvm::MachineFunction &MF = MFI.getMachineFunction();
113
114 for (auto VT : MFI.getParams())
115 Params.push_back(EVT(VT).getEVTString());
116 for (auto VT : MFI.getResults())
117 Results.push_back(EVT(VT).getEVTString());
118
119 // MFI.getWasmEHFuncInfo() is non-null only for functions with the
120 // personality function.
121 if (EHInfo) {
122 // SrcToUnwindDest can contain stale mappings in case BBs are removed in
123 // optimizations, in case, for example, they are unreachable. We should not
124 // include their info.
125 SmallPtrSet<const MachineBasicBlock *, 16> MBBs;
126 for (const auto &MBB : MF)
127 MBBs.insert(&MBB);
128 for (auto KV : EHInfo->SrcToUnwindDest) {
129 auto *SrcBB = KV.first.get<MachineBasicBlock *>();
130 auto *DestBB = KV.second.get<MachineBasicBlock *>();
131 if (MBBs.count(SrcBB) && MBBs.count(DestBB))
132 SrcToUnwindDest[SrcBB->getNumber()] = DestBB->getNumber();
133 }
134 }
135 }
136
mappingImpl(yaml::IO & YamlIO)137 void yaml::WebAssemblyFunctionInfo::mappingImpl(yaml::IO &YamlIO) {
138 MappingTraits<WebAssemblyFunctionInfo>::mapping(YamlIO, *this);
139 }
140
initializeBaseYamlFields(const yaml::WebAssemblyFunctionInfo & YamlMFI)141 void WebAssemblyFunctionInfo::initializeBaseYamlFields(
142 const yaml::WebAssemblyFunctionInfo &YamlMFI) {
143 CFGStackified = YamlMFI.CFGStackified;
144 for (auto VT : YamlMFI.Params)
145 addParam(WebAssembly::parseMVT(VT.Value));
146 for (auto VT : YamlMFI.Results)
147 addResult(WebAssembly::parseMVT(VT.Value));
148 if (WasmEHInfo) {
149 for (auto KV : YamlMFI.SrcToUnwindDest)
150 WasmEHInfo->setUnwindDest(MF.getBlockNumbered(KV.first),
151 MF.getBlockNumbered(KV.second));
152 }
153 }
154