1 files changed, 18 insertions, 22 deletions

diff --git a/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h b/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
index 6a60280900a9..89f607d84b71 100644
--- a/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
+++ b/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
@@ -39,18 +39,24 @@ class WebAssemblyFunctionInfo final : public MachineFunctionInfo {
   ///   - defined and used in LIFO order with other stack registers
   BitVector VRegStackified;
 
-  // One entry for each possible target reg. we expect it to be small.
-  std::vector<unsigned> PhysRegs;
+  // A virtual register holding the pointer to the vararg buffer for vararg
+  // functions. It is created and set in TLI::LowerFormalArguments and read by
+  // TLI::LowerVASTART
+  unsigned VarargVreg = -1U;
 
-public:
-  explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {
-    PhysRegs.resize(WebAssembly::NUM_TARGET_REGS, -1U);
-  }
+ public:
+  explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {}
   ~WebAssemblyFunctionInfo() override;
 
   void addParam(MVT VT) { Params.push_back(VT); }
   const std::vector<MVT> &getParams() const { return Params; }
 
+  unsigned getVarargBufferVreg() const {
+    assert(VarargVreg != -1U && "Vararg vreg hasn't been set");
+    return VarargVreg;
+  }
+  void setVarargBufferVreg(unsigned Reg) { VarargVreg = Reg; }
+
   static const unsigned UnusedReg = -1u;
 
   void stackifyVReg(unsigned VReg) {
@@ -71,25 +77,15 @@ public:
     WARegs[TargetRegisterInfo::virtReg2Index(VReg)] = WAReg;
   }
   unsigned getWAReg(unsigned Reg) const {
-    if (TargetRegisterInfo::isVirtualRegister(Reg)) {
-      assert(TargetRegisterInfo::virtReg2Index(Reg) < WARegs.size());
-      return WARegs[TargetRegisterInfo::virtReg2Index(Reg)];
-    }
-    return PhysRegs[Reg];
-  }
-  // If new virtual registers are created after initWARegs has been called,
-  // this function can be used to add WebAssembly register mappings for them.
-  void addWAReg(unsigned VReg, unsigned WAReg) {
-    assert(VReg = WARegs.size());
-    WARegs.push_back(WAReg);
+    assert(TargetRegisterInfo::virtReg2Index(Reg) < WARegs.size());
+    return WARegs[TargetRegisterInfo::virtReg2Index(Reg)];
   }
 
-  void addPReg(unsigned PReg, unsigned WAReg) {
-    assert(PReg < WebAssembly::NUM_TARGET_REGS);
-    assert(WAReg < -1U);
-    PhysRegs[PReg] = WAReg;
+  // For a given stackified WAReg, return the id number to print with push/pop.
+  static unsigned getWARegStackId(unsigned Reg) {
+    assert(Reg & INT32_MIN);
+    return Reg & INT32_MAX;
   }
-  const std::vector<unsigned> &getPhysRegs() const { return PhysRegs; }
 };
 
 } // end namespace llvm