1 files changed, 65 insertions, 0 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
new file mode 100644
index 000000000000..fdc0f561dcd9
--- /dev/null
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
@@ -0,0 +1,65 @@
+// WebAssemblyFrameLowering.h - TargetFrameLowering for WebAssembly -*- C++ -*-/
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This class implements WebAssembly-specific bits of
+/// TargetFrameLowering class.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYFRAMELOWERING_H
+#define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYFRAMELOWERING_H
+
+#include "llvm/CodeGen/TargetFrameLowering.h"
+
+namespace llvm {
+class MachineFrameInfo;
+
+class WebAssemblyFrameLowering final : public TargetFrameLowering {
+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 __stack_pointer
+  /// global).
+  // TODO: (ABI) Revisit and decide how large it should be.
+  static const size_t RedZoneSize = 128;
+
+  WebAssemblyFrameLowering()
+      : TargetFrameLowering(StackGrowsDown, /*StackAlignment=*/Align(16),
+                            /*LocalAreaOffset=*/0,
+                            /*TransientStackAlignment=*/Align(16),
+                            /*StackRealignable=*/true) {}
+
+  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;
+  void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
+
+  bool hasFP(const MachineFunction &MF) const override;
+  bool hasReservedCallFrame(const MachineFunction &MF) const override;
+
+  bool needsPrologForEH(const MachineFunction &MF) const;
+
+  /// Write SP back to __stack_pointer global.
+  void writeSPToGlobal(unsigned SrcReg, MachineFunction &MF,
+                       MachineBasicBlock &MBB,
+                       MachineBasicBlock::iterator &InsertStore,
+                       const DebugLoc &DL) const;
+
+private:
+  bool hasBP(const MachineFunction &MF) const;
+  bool needsSPForLocalFrame(const MachineFunction &MF) const;
+  bool needsSP(const MachineFunction &MF) const;
+  bool needsSPWriteback(const MachineFunction &MF) const;
+};
+
+} // end namespace llvm
+
+#endif