[WebAssembly] Initial WebAssembly backend

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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241022 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/WebAssembly/WebAssemblyTargetMachine.h

@@ -0,0 +1,51 @@
+// WebAssemblyTargetMachine.h - Define TargetMachine 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 file declares the WebAssembly-specific subclass of
+/// TargetMachine.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYTARGETMACHINE_H
+#define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYTARGETMACHINE_H
+
+#include "WebAssemblySubtarget.h"
+#include "llvm/Target/TargetMachine.h"
+
+namespace llvm {
+
+class WebAssemblyTargetMachine final : public LLVMTargetMachine {
+  std::unique_ptr<TargetLoweringObjectFile> TLOF;
+  mutable StringMap<std::unique_ptr<WebAssemblySubtarget>> SubtargetMap;
+
+public:
+  WebAssemblyTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
+                           StringRef FS, const TargetOptions &Options,
+                           Reloc::Model RM, CodeModel::Model CM,
+                           CodeGenOpt::Level OL);
+
+  ~WebAssemblyTargetMachine() override;
+  const WebAssemblySubtarget *
+  getSubtargetImpl(const Function &F) const override;
+
+  // Pass Pipeline Configuration
+  TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
+
+  TargetLoweringObjectFile *getObjFileLowering() const override {
+    return TLOF.get();
+  }
+
+  /// \brief Get the TargetIRAnalysis for this target.
+  TargetIRAnalysis getTargetIRAnalysis() override;
+};
+
+} // end namespace llvm
+
+#endif