[WebAssembly] Initial WebAssembly backend

This WebAssembly backend is just a skeleton at this time and is not yet
functional.

llvm-svn: 241022

1 files changed, 48 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
new file mode 100644
index 00000000000..0b112d02c0b
--- /dev/null
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.h
@@ -0,0 +1,48 @@
+// WebAssemblyFrameLowering.h - TargetFrameLowering for WebAssembly -*- C++ -*-/
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief 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/Target/TargetFrameLowering.h"
+
+namespace llvm {
+
+class WebAssemblyFrameLowering final : public TargetFrameLowering {
+public:
+  WebAssemblyFrameLowering()
+      : TargetFrameLowering(StackGrowsDown, /*StackAlignment=*/16,
+                            /*LocalAreaOffset=*/0,
+                            /*TransientStackAlignment=*/16,
+                            /*StackRealignable=*/true) {}
+
+  void
+  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;
+
+  void processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+                                            RegScavenger *RS) const override;
+};
+
+} // end namespace llvm
+
+#endif