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