[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/WebAssemblySubtarget.cpp

@@ -0,0 +1,48 @@
+//===-- WebAssemblySubtarget.cpp - WebAssembly Subtarget Information ------===//
+//
+//                     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 implements the WebAssembly-specific subclass of
+/// TargetSubtarget.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssemblyInstrInfo.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "WebAssemblySubtarget.h"
+#include "llvm/Support/TargetRegistry.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "subtarget"
+
+#define GET_SUBTARGETINFO_CTOR
+#define GET_SUBTARGETINFO_TARGET_DESC
+#include "WebAssemblyGenSubtargetInfo.inc"
+
+WebAssemblySubtarget &
+WebAssemblySubtarget::initializeSubtargetDependencies(StringRef FS) {
+  // Determine default and user-specified characteristics
+
+  if (CPUString.empty())
+    CPUString = "generic";
+
+  ParseSubtargetFeatures(CPUString, FS);
+  return *this;
+}
+
+WebAssemblySubtarget::WebAssemblySubtarget(const Triple &TT,
+                                           const std::string &CPU,
+                                           const std::string &FS,
+                                           const TargetMachine &TM)
+    : WebAssemblyGenSubtargetInfo(TT, CPU, FS), HasSIMD(true), CPUString(CPU),
+      TargetTriple(TT), FrameLowering(),
+      InstrInfo(initializeSubtargetDependencies(FS)),
+      TSInfo(TM.getDataLayout()), TLInfo(TM, *this) {}
+
+bool WebAssemblySubtarget::enableMachineScheduler() const { return true; }