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diff --git a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
new file mode 100644
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--- /dev/null
+++ b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
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+//===- WebAssemblyTargetMachine.cpp - Define TargetMachine for WebAssembly -==//
+//
+//                     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 defines the WebAssembly-specific subclass of TargetMachine.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssembly.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "WebAssemblyTargetMachine.h"
+#include "WebAssemblyTargetObjectFile.h"
+#include "WebAssemblyTargetTransformInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/RegAllocRegistry.h"
+#include "llvm/IR/Function.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Transforms/Scalar.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "wasm"
+
+extern "C" void LLVMInitializeWebAssemblyTarget() {
+  // Register the target.
+  RegisterTargetMachine<WebAssemblyTargetMachine> X(TheWebAssemblyTarget32);
+  RegisterTargetMachine<WebAssemblyTargetMachine> Y(TheWebAssemblyTarget64);
+}
+
+//===----------------------------------------------------------------------===//
+// WebAssembly Lowering public interface.
+//===----------------------------------------------------------------------===//
+
+/// Create an WebAssembly architecture model.
+///
+WebAssemblyTargetMachine::WebAssemblyTargetMachine(
+    const Target &T, const Triple &TT, StringRef CPU, StringRef FS,
+    const TargetOptions &Options, Reloc::Model RM, CodeModel::Model CM,
+    CodeGenOpt::Level OL)
+    : LLVMTargetMachine(T, TT.isArch64Bit() ? "e-p:64:64-i64:64-n32:64-S128"
+                                            : "e-p:32:32-i64:64-n32:64-S128",
+                        TT, CPU, FS, Options, RM, CM, OL),
+      TLOF(make_unique<WebAssemblyTargetObjectFile>()) {
+  // WebAssembly type-checks expressions, but a noreturn function with a return
+  // type that doesn't match the context will cause a check failure. So we lower
+  // LLVM 'unreachable' to ISD::TRAP and then lower that to WebAssembly's
+  // 'unreachable' expression which is meant for that case.
+  this->Options.TrapUnreachable = true;
+
+  initAsmInfo();
+
+  // We need a reducible CFG, so disable some optimizations which tend to
+  // introduce irreducibility.
+  setRequiresStructuredCFG(true);
+}
+
+WebAssemblyTargetMachine::~WebAssemblyTargetMachine() {}
+
+const WebAssemblySubtarget *
+WebAssemblyTargetMachine::getSubtargetImpl(const Function &F) const {
+  Attribute CPUAttr = F.getFnAttribute("target-cpu");
+  Attribute FSAttr = F.getFnAttribute("target-features");
+
+  std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
+                        ? CPUAttr.getValueAsString().str()
+                        : TargetCPU;
+  std::string FS = !FSAttr.hasAttribute(Attribute::None)
+                       ? FSAttr.getValueAsString().str()
+                       : TargetFS;
+
+  auto &I = SubtargetMap[CPU + FS];
+  if (!I) {
+    // This needs to be done before we create a new subtarget since any
+    // creation will depend on the TM and the code generation flags on the
+    // function that reside in TargetOptions.
+    resetTargetOptions(F);
+    I = llvm::make_unique<WebAssemblySubtarget>(TargetTriple, CPU, FS, *this);
+  }
+  return I.get();
+}
+
+namespace {
+/// WebAssembly Code Generator Pass Configuration Options.
+class WebAssemblyPassConfig final : public TargetPassConfig {
+public:
+  WebAssemblyPassConfig(WebAssemblyTargetMachine *TM, PassManagerBase &PM)
+      : TargetPassConfig(TM, PM) {}
+
+  WebAssemblyTargetMachine &getWebAssemblyTargetMachine() const {
+    return getTM<WebAssemblyTargetMachine>();
+  }
+
+  FunctionPass *createTargetRegisterAllocator(bool) override;
+
+  void addIRPasses() override;
+  bool addInstSelector() override;
+  bool addILPOpts() override;
+  void addPreRegAlloc() override;
+  void addPostRegAlloc() override;
+  void addPreEmitPass() override;
+};
+} // end anonymous namespace
+
+TargetIRAnalysis WebAssemblyTargetMachine::getTargetIRAnalysis() {
+  return TargetIRAnalysis([this](const Function &F) {
+    return TargetTransformInfo(WebAssemblyTTIImpl(this, F));
+  });
+}
+
+TargetPassConfig *
+WebAssemblyTargetMachine::createPassConfig(PassManagerBase &PM) {
+  return new WebAssemblyPassConfig(this, PM);
+}
+
+FunctionPass *WebAssemblyPassConfig::createTargetRegisterAllocator(bool) {
+  return nullptr; // No reg alloc
+}
+
+//===----------------------------------------------------------------------===//
+// The following functions are called from lib/CodeGen/Passes.cpp to modify
+// the CodeGen pass sequence.
+//===----------------------------------------------------------------------===//
+
+void WebAssemblyPassConfig::addIRPasses() {
+  if (TM->Options.ThreadModel == ThreadModel::Single)
+    // In "single" mode, atomics get lowered to non-atomics.
+    addPass(createLowerAtomicPass());
+  else
+    // Expand some atomic operations. WebAssemblyTargetLowering has hooks which
+    // control specifically what gets lowered.
+    addPass(createAtomicExpandPass(TM));
+
+  // Optimize "returned" function attributes.
+  addPass(createWebAssemblyOptimizeReturned());
+
+  TargetPassConfig::addIRPasses();
+}
+
+bool WebAssemblyPassConfig::addInstSelector() {
+  (void)TargetPassConfig::addInstSelector();
+  addPass(
+      createWebAssemblyISelDag(getWebAssemblyTargetMachine(), getOptLevel()));
+  // Run the argument-move pass immediately after the ScheduleDAG scheduler
+  // so that we can fix up the ARGUMENT instructions before anything else
+  // sees them in the wrong place.
+  addPass(createWebAssemblyArgumentMove());
+  return false;
+}
+
+bool WebAssemblyPassConfig::addILPOpts() {
+  (void)TargetPassConfig::addILPOpts();
+  return true;
+}
+
+void WebAssemblyPassConfig::addPreRegAlloc() {
+  TargetPassConfig::addPreRegAlloc();
+
+  // Prepare store instructions for register stackifying.
+  addPass(createWebAssemblyStoreResults());
+}
+
+void WebAssemblyPassConfig::addPostRegAlloc() {
+  // TODO: The following CodeGen passes don't currently support code containing
+  // virtual registers. Consider removing their restrictions and re-enabling
+  // them.
+  //
+  // We use our own PrologEpilogInserter which is very slightly modified to
+  // tolerate virtual registers.
+  disablePass(&PrologEpilogCodeInserterID);
+  // Fails with: should be run after register allocation.
+  disablePass(&MachineCopyPropagationID);
+
+  // Mark registers as representing wasm's expression stack.
+  addPass(createWebAssemblyRegStackify());
+
+  // Run the register coloring pass to reduce the total number of registers.
+  addPass(createWebAssemblyRegColoring());
+
+  TargetPassConfig::addPostRegAlloc();
+
+  // Run WebAssembly's version of the PrologEpilogInserter. Target-independent
+  // PEI runs after PostRegAlloc and after ShrinkWrap. Putting it here will run
+  // PEI before ShrinkWrap but otherwise in the same position in the order.
+  addPass(createWebAssemblyPEI());
+}
+
+void WebAssemblyPassConfig::addPreEmitPass() {
+  TargetPassConfig::addPreEmitPass();
+
+  // Put the CFG in structured form; insert BLOCK and LOOP markers.
+  addPass(createWebAssemblyCFGStackify());
+
+  // Lower br_unless into br_if.
+  addPass(createWebAssemblyLowerBrUnless());
+
+  // Create a mapping from LLVM CodeGen virtual registers to wasm registers.
+  addPass(createWebAssemblyRegNumbering());
+
+  // Perform the very last peephole optimizations on the code.
+  addPass(createWebAssemblyPeephole());
+}