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