include/llvm/Support/SmallVectorMemoryBuffer.h

   1 //===- SmallVectorMemoryBuffer.h --------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file declares a wrapper class to hold the memory into which an
  10 // object will be generated.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_EXECUTIONENGINE_OBJECTMEMORYBUFFER_H
  15 #define LLVM_EXECUTIONENGINE_OBJECTMEMORYBUFFER_H
  16
  17 #include "llvm/ADT/SmallVector.h"
  18 #include "llvm/Support/MemoryBuffer.h"
  19 #include "llvm/Support/raw_ostream.h"
  20
  21 namespace llvm {
  22
  23 /// SmallVector-backed MemoryBuffer instance.
  24 ///
  25 /// This class enables efficient construction of MemoryBuffers from SmallVector
  26 /// instances. This is useful for MCJIT and Orc, where object files are streamed
  27 /// into SmallVectors, then inspected using ObjectFile (which takes a
  28 /// MemoryBuffer).
  29 class SmallVectorMemoryBuffer : public MemoryBuffer {
  30 public:
  31   /// Construct an SmallVectorMemoryBuffer from the given SmallVector
  32   /// r-value.
  33   ///
  34   /// FIXME: It'd be nice for this to be a non-templated constructor taking a
  35   /// SmallVectorImpl here instead of a templated one taking a SmallVector<N>,
  36   /// but SmallVector's move-construction/assignment currently only take
  37   /// SmallVectors. If/when that is fixed we can simplify this constructor and
  38   /// the following one.
  39   SmallVectorMemoryBuffer(SmallVectorImpl<char> &&SV)
  40       : SV(std::move(SV)), BufferName("<in-memory object>") {
  41     init(this->SV.begin(), this->SV.end(), false);
  42   }
  43
  44   /// Construct a named SmallVectorMemoryBuffer from the given
  45   /// SmallVector r-value and StringRef.
  46   SmallVectorMemoryBuffer(SmallVectorImpl<char> &&SV, StringRef Name)
  47       : SV(std::move(SV)), BufferName(Name) {
  48     init(this->SV.begin(), this->SV.end(), false);
  49   }
  50
  51   // Key function.
  52   ~SmallVectorMemoryBuffer() override;
  53
  54   StringRef getBufferIdentifier() const override { return BufferName; }
  55
  56   BufferKind getBufferKind() const override { return MemoryBuffer_Malloc; }
  57
  58 private:
  59   SmallVector<char, 0> SV;
  60   std::string BufferName;
  61 };
  62
  63 } // namespace llvm
  64
  65 #endif