1 files changed, 16 insertions, 5 deletions
diff --git a/lib/Target/WebAssembly/WebAssemblyFrameLowering.h b/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
index 5f4708fe77ed..e20fc5df7443 100644
--- a/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
+++ b/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
@@ -19,18 +19,24 @@
 #include "llvm/Target/TargetFrameLowering.h"
 
 namespace llvm {
+class MachineFrameInfo;
 
 class WebAssemblyFrameLowering final : public TargetFrameLowering {
-public:
+ public:
+  /// Size of the red zone for the user stack (leaf functions can use this much
+  /// space below the stack pointer without writing it back to memory).
+  // TODO: (ABI) Revisit and decide how large it should be.
+  static const size_t RedZoneSize = 128;
+
   WebAssemblyFrameLowering()
       : TargetFrameLowering(StackGrowsDown, /*StackAlignment=*/16,
                             /*LocalAreaOffset=*/0,
                             /*TransientStackAlignment=*/16,
                             /*StackRealignable=*/true) {}
 
-  void
-  eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
-                                MachineBasicBlock::iterator I) const override;
+  MachineBasicBlock::iterator eliminateCallFramePseudoInstr(
+      MachineFunction &MF, MachineBasicBlock &MBB,
+      MachineBasicBlock::iterator I) const override;
 
   /// These methods insert prolog and epilog code into the function.
   void emitPrologue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
@@ -38,8 +44,13 @@ public:
 
   bool hasFP(const MachineFunction &MF) const override;
   bool hasReservedCallFrame(const MachineFunction &MF) const override;
+
+ private:
+  bool needsSP(const MachineFunction &MF, const MachineFrameInfo &MFI) const;
+  bool needsSPWriteback(const MachineFunction &MF,
+                        const MachineFrameInfo &MFI) const;
 };
 
-} // end namespace llvm
+}  // end namespace llvm
 
 #endif