1 files changed, 72 insertions, 0 deletions
diff --git a/include/llvm/MCA/CodeEmitter.h b/include/llvm/MCA/CodeEmitter.h
new file mode 100644
index 000000000000..c8d222bd8c2f
--- /dev/null
+++ b/include/llvm/MCA/CodeEmitter.h
@@ -0,0 +1,72 @@
+//===--------------------- CodeEmitter.h ------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// A utility class used to compute instruction encodings. It buffers encodings
+/// for later usage. It exposes a simple API to compute and get the encodings as
+/// StringRef.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MCA_CODEEMITTER_H
+#define LLVM_MCA_CODEEMITTER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MCA/Instruction.h"
+#include "llvm/MCA/Support.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <string>
+
+namespace llvm {
+namespace mca {
+
+/// A utility class used to compute instruction encodings for a code region.
+///
+/// It provides a simple API to compute and return instruction encodings as
+/// strings. Encodings are cached internally for later usage.
+class CodeEmitter {
+  const MCSubtargetInfo &STI;
+  const MCAsmBackend &MAB;
+  const MCCodeEmitter &MCE;
+
+  SmallString<256> Code;
+  raw_svector_ostream VecOS;
+  ArrayRef<MCInst> Sequence;
+
+  // An EncodingInfo pair stores <base, length> information.  Base (i.e. first)
+  // is an index to the `Code`. Length (i.e. second) is the encoding size.
+  using EncodingInfo = std::pair<unsigned, unsigned>;
+
+  // A cache of encodings.
+  SmallVector<EncodingInfo, 16> Encodings;
+
+  EncodingInfo getOrCreateEncodingInfo(unsigned MCID);
+
+public:
+  CodeEmitter(const MCSubtargetInfo &ST, const MCAsmBackend &AB,
+              const MCCodeEmitter &CE, ArrayRef<MCInst> S)
+      : STI(ST), MAB(AB), MCE(CE), VecOS(Code), Sequence(S),
+        Encodings(S.size()) {}
+
+  StringRef getEncoding(unsigned MCID) {
+    EncodingInfo EI = getOrCreateEncodingInfo(MCID);
+    return StringRef(&Code[EI.first], EI.second);
+  }
+};
+
+} // namespace mca
+} // namespace llvm
+
+#endif // LLVM_MCA_CODEEMITTER_H