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diff --git a/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp b/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp
new file mode 100644
index 00000000000..112ac45b478
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+++ b/llvm/tools/llvm-exegesis/lib/SnippetFile.cpp
@@ -0,0 +1,164 @@
+//===-- SnippetFile.cpp -----------------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "SnippetFile.h"
+#include "BenchmarkRunner.h" // FIXME: Pull BenchmarkFailure out of there.
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/MC/MCParser/MCTargetAsmParser.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetRegistry.h"
+#include <string>
+
+namespace llvm {
+namespace exegesis {
+namespace {
+
+// An MCStreamer that reads a BenchmarkCode definition from a file.
+class BenchmarkCodeStreamer : public MCStreamer, public AsmCommentConsumer {
+public:
+  explicit BenchmarkCodeStreamer(MCContext *Context,
+                                 const MCRegisterInfo *TheRegInfo,
+                                 BenchmarkCode *Result)
+      : MCStreamer(*Context), RegInfo(TheRegInfo), Result(Result) {}
+
+  // Implementation of the MCStreamer interface. We only care about
+  // instructions.
+  void EmitInstruction(const MCInst &Instruction,
+                       const MCSubtargetInfo &STI) override {
+    Result->Instructions.push_back(Instruction);
+  }
+
+  // Implementation of the AsmCommentConsumer.
+  void HandleComment(SMLoc Loc, StringRef CommentText) override {
+    CommentText = CommentText.trim();
+    if (!CommentText.consume_front("LLVM-EXEGESIS-"))
+      return;
+    if (CommentText.consume_front("DEFREG")) {
+      // LLVM-EXEGESIS-DEFREF <reg> <hex_value>
+      RegisterValue RegVal;
+      SmallVector<StringRef, 2> Parts;
+      CommentText.split(Parts, ' ', /*unlimited splits*/ -1,
+                        /*do not keep empty strings*/ false);
+      if (Parts.size() != 2) {
+        errs() << "invalid comment 'LLVM-EXEGESIS-DEFREG " << CommentText
+               << "', expected two parameters <REG> <HEX_VALUE>\n";
+        ++InvalidComments;
+        return;
+      }
+      if (!(RegVal.Register = findRegisterByName(Parts[0].trim()))) {
+        errs() << "unknown register '" << Parts[0]
+               << "' in 'LLVM-EXEGESIS-DEFREG " << CommentText << "'\n";
+        ++InvalidComments;
+        return;
+      }
+      const StringRef HexValue = Parts[1].trim();
+      RegVal.Value = APInt(
+          /* each hex digit is 4 bits */ HexValue.size() * 4, HexValue, 16);
+      Result->RegisterInitialValues.push_back(std::move(RegVal));
+      return;
+    }
+    if (CommentText.consume_front("LIVEIN")) {
+      // LLVM-EXEGESIS-LIVEIN <reg>
+      const auto RegName = CommentText.ltrim();
+      if (unsigned Reg = findRegisterByName(RegName))
+        Result->LiveIns.push_back(Reg);
+      else {
+        errs() << "unknown register '" << RegName
+               << "' in 'LLVM-EXEGESIS-LIVEIN " << CommentText << "'\n";
+        ++InvalidComments;
+      }
+      return;
+    }
+  }
+
+  unsigned numInvalidComments() const { return InvalidComments; }
+
+private:
+  // We only care about instructions, we don't implement this part of the API.
+  void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                        unsigned ByteAlignment) override {}
+  bool EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
+    return false;
+  }
+  void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
+                            unsigned ValueSize,
+                            unsigned MaxBytesToEmit) override {}
+  void EmitZerofill(MCSection *Section, MCSymbol *Symbol, uint64_t Size,
+                    unsigned ByteAlignment, SMLoc Loc) override {}
+
+  unsigned findRegisterByName(const StringRef RegName) const {
+    // FIXME: Can we do better than this ?
+    for (unsigned I = 0, E = RegInfo->getNumRegs(); I < E; ++I) {
+      if (RegName == RegInfo->getName(I))
+        return I;
+    }
+    errs() << "'" << RegName
+           << "' is not a valid register name for the target\n";
+    return 0;
+  }
+
+  const MCRegisterInfo *const RegInfo;
+  BenchmarkCode *const Result;
+  unsigned InvalidComments = 0;
+};
+
+} // namespace
+
+// Reads code snippets from file `Filename`.
+Expected<std::vector<BenchmarkCode>> readSnippets(const LLVMState &State,
+                                                  StringRef Filename) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> BufferPtr =
+      MemoryBuffer::getFileOrSTDIN(Filename);
+  if (std::error_code EC = BufferPtr.getError()) {
+    return make_error<BenchmarkFailure>("cannot read snippet: " + Filename +
+                                        ": " + EC.message());
+  }
+  SourceMgr SM;
+  SM.AddNewSourceBuffer(std::move(BufferPtr.get()), SMLoc());
+
+  BenchmarkCode Result;
+
+  MCObjectFileInfo ObjectFileInfo;
+  const TargetMachine &TM = State.getTargetMachine();
+  MCContext Context(TM.getMCAsmInfo(), TM.getMCRegisterInfo(), &ObjectFileInfo);
+  ObjectFileInfo.InitMCObjectFileInfo(TM.getTargetTriple(), /*PIC*/ false,
+                                      Context);
+  BenchmarkCodeStreamer Streamer(&Context, TM.getMCRegisterInfo(), &Result);
+  const std::unique_ptr<MCAsmParser> AsmParser(
+      createMCAsmParser(SM, Context, Streamer, *TM.getMCAsmInfo()));
+  if (!AsmParser)
+    return make_error<BenchmarkFailure>("cannot create asm parser");
+  AsmParser->getLexer().setCommentConsumer(&Streamer);
+
+  const std::unique_ptr<MCTargetAsmParser> TargetAsmParser(
+      TM.getTarget().createMCAsmParser(*TM.getMCSubtargetInfo(), *AsmParser,
+                                       *TM.getMCInstrInfo(),
+                                       MCTargetOptions()));
+
+  if (!TargetAsmParser)
+    return make_error<BenchmarkFailure>("cannot create target asm parser");
+  AsmParser->setTargetParser(*TargetAsmParser);
+
+  if (AsmParser->Run(false))
+    return make_error<BenchmarkFailure>("cannot parse asm file");
+  if (Streamer.numInvalidComments())
+    return make_error<BenchmarkFailure>(
+        Twine("found ")
+            .concat(Twine(Streamer.numInvalidComments()))
+            .concat(" invalid LLVM-EXEGESIS comments"));
+  return std::vector<BenchmarkCode>{std::move(Result)};
+}
+
+} // namespace exegesis
+} // namespace llvm