1 // WebAssemblyMachineFunctionInfo.h-WebAssembly machine function info-*- C++ -*-
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// This file declares WebAssembly-specific per-machine-function
12 /// information.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
17 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYMACHINEFUNCTIONINFO_H
18 
19 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
20 #include "llvm/CodeGen/MachineRegisterInfo.h"
21 
22 namespace llvm {
23 
24 /// This class is derived from MachineFunctionInfo and contains private
25 /// WebAssembly-specific information for each MachineFunction.
26 class WebAssemblyFunctionInfo final : public MachineFunctionInfo {
27   MachineFunction &MF;
28 
29   std::vector<MVT> Params;
30   std::vector<MVT> Results;
31   std::vector<MVT> Locals;
32 
33   /// A mapping from CodeGen vreg index to WebAssembly register number.
34   std::vector<unsigned> WARegs;
35 
36   /// A mapping from CodeGen vreg index to a boolean value indicating whether
37   /// the given register is considered to be "stackified", meaning it has been
38   /// determined or made to meet the stack requirements:
39   ///   - single use (per path)
40   ///   - single def (per path)
41   ///   - defined and used in LIFO order with other stack registers
42   BitVector VRegStackified;
43 
44   // A virtual register holding the pointer to the vararg buffer for vararg
45   // functions. It is created and set in TLI::LowerFormalArguments and read by
46   // TLI::LowerVASTART
47   unsigned VarargVreg = -1U;
48 
49   // A virtual register holding the base pointer for functions that have
50   // overaligned values on the user stack.
51   unsigned BasePtrVreg = -1U;
52 
53  public:
54   explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {}
55   ~WebAssemblyFunctionInfo() override;
56 
57   void addParam(MVT VT) { Params.push_back(VT); }
58   const std::vector<MVT> &getParams() const { return Params; }
59 
60   void addResult(MVT VT) { Results.push_back(VT); }
61   const std::vector<MVT> &getResults() const { return Results; }
62 
63   void clearParamsAndResults() { Params.clear(); Results.clear(); }
64 
65   void setNumLocals(size_t NumLocals) { Locals.resize(NumLocals, MVT::i32); }
66   void setLocal(size_t i, MVT VT) { Locals[i] = VT; }
67   void addLocal(MVT VT) { Locals.push_back(VT); }
68   const std::vector<MVT> &getLocals() const { return Locals; }
69 
70   unsigned getVarargBufferVreg() const {
71     assert(VarargVreg != -1U && "Vararg vreg hasn't been set");
72     return VarargVreg;
73   }
74   void setVarargBufferVreg(unsigned Reg) { VarargVreg = Reg; }
75 
76   unsigned getBasePointerVreg() const {
77     assert(BasePtrVreg != -1U && "Base ptr vreg hasn't been set");
78     return BasePtrVreg;
79   }
80   void setBasePointerVreg(unsigned Reg) { BasePtrVreg = Reg; }
81 
82   static const unsigned UnusedReg = -1u;
83 
84   void stackifyVReg(unsigned VReg) {
85     assert(MF.getRegInfo().getUniqueVRegDef(VReg));
86     if (TargetRegisterInfo::virtReg2Index(VReg) >= VRegStackified.size())
87       VRegStackified.resize(TargetRegisterInfo::virtReg2Index(VReg) + 1);
88     VRegStackified.set(TargetRegisterInfo::virtReg2Index(VReg));
89   }
90   bool isVRegStackified(unsigned VReg) const {
91     if (TargetRegisterInfo::virtReg2Index(VReg) >= VRegStackified.size())
92       return false;
93     return VRegStackified.test(TargetRegisterInfo::virtReg2Index(VReg));
94   }
95 
96   void initWARegs();
97   void setWAReg(unsigned VReg, unsigned WAReg) {
98     assert(WAReg != UnusedReg);
99     assert(TargetRegisterInfo::virtReg2Index(VReg) < WARegs.size());
100     WARegs[TargetRegisterInfo::virtReg2Index(VReg)] = WAReg;
101   }
102   unsigned getWAReg(unsigned Reg) const {
103     assert(TargetRegisterInfo::virtReg2Index(Reg) < WARegs.size());
104     return WARegs[TargetRegisterInfo::virtReg2Index(Reg)];
105   }
106 
107   // For a given stackified WAReg, return the id number to print with push/pop.
108   static unsigned getWARegStackId(unsigned Reg) {
109     assert(Reg & INT32_MIN);
110     return Reg & INT32_MAX;
111   }
112 };
113 
114 void ComputeLegalValueVTs(const Function &F, const TargetMachine &TM,
115                           Type *Ty, SmallVectorImpl<MVT> &ValueVTs);
116 
117 void ComputeSignatureVTs(const Function &F, const TargetMachine &TM,
118                          SmallVectorImpl<MVT> &Params,
119                          SmallVectorImpl<MVT> &Results);
120 
121 } // end namespace llvm
122 
123 #endif
124