lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h

   1 // WebAssemblyMachineFunctionInfo.h-WebAssembly machine function info-*- C++ -*-
   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 declares WebAssembly-specific per-machine-function
  11 /// information.
  12 ///
  13 //===----------------------------------------------------------------------===//
  14
  15 #ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
  16 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
  17
  18 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
  19 #include "llvm/BinaryFormat/Wasm.h"
  20 #include "llvm/CodeGen/MIRYamlMapping.h"
  21 #include "llvm/CodeGen/MachineRegisterInfo.h"
  22 #include "llvm/MC/MCSymbolWasm.h"
  23
  24 namespace llvm {
  25
  26 namespace yaml {
  27 struct WebAssemblyFunctionInfo;
  28 }
  29
  30 /// This class is derived from MachineFunctionInfo and contains private
  31 /// WebAssembly-specific information for each MachineFunction.
  32 class WebAssemblyFunctionInfo final : public MachineFunctionInfo {
  33   MachineFunction &MF;
  34
  35   std::vector<MVT> Params;
  36   std::vector<MVT> Results;
  37   std::vector<MVT> Locals;
  38
  39   /// A mapping from CodeGen vreg index to WebAssembly register number.
  40   std::vector<unsigned> WARegs;
  41
  42   /// A mapping from CodeGen vreg index to a boolean value indicating whether
  43   /// the given register is considered to be "stackified", meaning it has been
  44   /// determined or made to meet the stack requirements:
  45   ///   - single use (per path)
  46   ///   - single def (per path)
  47   ///   - defined and used in LIFO order with other stack registers
  48   BitVector VRegStackified;
  49
  50   // A virtual register holding the pointer to the vararg buffer for vararg
  51   // functions. It is created and set in TLI::LowerFormalArguments and read by
  52   // TLI::LowerVASTART
  53   unsigned VarargVreg = -1U;
  54
  55   // A virtual register holding the base pointer for functions that have
  56   // overaligned values on the user stack.
  57   unsigned BasePtrVreg = -1U;
  58
  59   // Function properties.
  60   bool CFGStackified = false;
  61
  62 public:
  63   explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {}
  64   ~WebAssemblyFunctionInfo() override;
  65   void initializeBaseYamlFields(const yaml::WebAssemblyFunctionInfo &YamlMFI);
  66
  67   void addParam(MVT VT) { Params.push_back(VT); }
  68   const std::vector<MVT> &getParams() const { return Params; }
  69
  70   void addResult(MVT VT) { Results.push_back(VT); }
  71   const std::vector<MVT> &getResults() const { return Results; }
  72
  73   void clearParamsAndResults() {
  74     Params.clear();
  75     Results.clear();
  76   }
  77
  78   void setNumLocals(size_t NumLocals) { Locals.resize(NumLocals, MVT::i32); }
  79   void setLocal(size_t i, MVT VT) { Locals[i] = VT; }
  80   void addLocal(MVT VT) { Locals.push_back(VT); }
  81   const std::vector<MVT> &getLocals() const { return Locals; }
  82
  83   unsigned getVarargBufferVreg() const {
  84     assert(VarargVreg != -1U && "Vararg vreg hasn't been set");
  85     return VarargVreg;
  86   }
  87   void setVarargBufferVreg(unsigned Reg) { VarargVreg = Reg; }
  88
  89   unsigned getBasePointerVreg() const {
  90     assert(BasePtrVreg != -1U && "Base ptr vreg hasn't been set");
  91     return BasePtrVreg;
  92   }
  93   void setBasePointerVreg(unsigned Reg) { BasePtrVreg = Reg; }
  94
  95   static const unsigned UnusedReg = -1u;
  96
  97   void stackifyVReg(unsigned VReg) {
  98     assert(MF.getRegInfo().getUniqueVRegDef(VReg));
  99     auto I = TargetRegisterInfo::virtReg2Index(VReg);
 100     if (I >= VRegStackified.size())
 101       VRegStackified.resize(I + 1);
 102     VRegStackified.set(I);
 103   }
 104   bool isVRegStackified(unsigned VReg) const {
 105     auto I = TargetRegisterInfo::virtReg2Index(VReg);
 106     if (I >= VRegStackified.size())
 107       return false;
 108     return VRegStackified.test(I);
 109   }
 110
 111   void initWARegs();
 112   void setWAReg(unsigned VReg, unsigned WAReg) {
 113     assert(WAReg != UnusedReg);
 114     auto I = TargetRegisterInfo::virtReg2Index(VReg);
 115     assert(I < WARegs.size());
 116     WARegs[I] = WAReg;
 117   }
 118   unsigned getWAReg(unsigned VReg) const {
 119     auto I = TargetRegisterInfo::virtReg2Index(VReg);
 120     assert(I < WARegs.size());
 121     return WARegs[I];
 122   }
 123
 124   // For a given stackified WAReg, return the id number to print with push/pop.
 125   static unsigned getWARegStackId(unsigned Reg) {
 126     assert(Reg & INT32_MIN);
 127     return Reg & INT32_MAX;
 128   }
 129
 130   bool isCFGStackified() const { return CFGStackified; }
 131   void setCFGStackified(bool Value = true) { CFGStackified = Value; }
 132 };
 133
 134 void computeLegalValueVTs(const Function &F, const TargetMachine &TM, Type *Ty,
 135                           SmallVectorImpl<MVT> &ValueVTs);
 136
 137 // Compute the signature for a given FunctionType (Ty). Note that it's not the
 138 // signature for F (F is just used to get varous context)
 139 void computeSignatureVTs(const FunctionType *Ty, const Function &F,
 140                          const TargetMachine &TM, SmallVectorImpl<MVT> &Params,
 141                          SmallVectorImpl<MVT> &Results);
 142
 143 void valTypesFromMVTs(const ArrayRef<MVT> &In,
 144                       SmallVectorImpl<wasm::ValType> &Out);
 145
 146 std::unique_ptr<wasm::WasmSignature>
 147 signatureFromMVTs(const SmallVectorImpl<MVT> &Results,
 148                   const SmallVectorImpl<MVT> &Params);
 149
 150 namespace yaml {
 151
 152 struct WebAssemblyFunctionInfo final : public yaml::MachineFunctionInfo {
 153   bool CFGStackified = false;
 154
 155   WebAssemblyFunctionInfo() = default;
 156   WebAssemblyFunctionInfo(const llvm::WebAssemblyFunctionInfo &MFI);
 157
 158   void mappingImpl(yaml::IO &YamlIO) override;
 159   ~WebAssemblyFunctionInfo() = default;
 160 };
 161
 162 template <> struct MappingTraits<WebAssemblyFunctionInfo> {
 163   static void mapping(IO &YamlIO, WebAssemblyFunctionInfo &MFI) {
 164     YamlIO.mapOptional("isCFGStackified", MFI.CFGStackified, false);
 165   }
 166 };
 167
 168 } // end namespace yaml
 169
 170 } // end namespace llvm
 171
 172 #endif