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1 //===- CompileUtils.h - Utilities for compiling IR in the JIT ---*- 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 // Contains utilities for compiling IR to object files.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_EXECUTIONENGINE_ORC_COMPILEUTILS_H
15 #define LLVM_EXECUTIONENGINE_ORC_COMPILEUTILS_H
16 
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/ExecutionEngine/ObjectCache.h"
19 #include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
20 #include "llvm/IR/LegacyPassManager.h"
21 #include "llvm/Object/Binary.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/Error.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/MemoryBuffer.h"
26 #include "llvm/Support/SmallVectorMemoryBuffer.h"
27 #include "llvm/Support/raw_ostream.h"
28 #include "llvm/Target/TargetMachine.h"
29 #include <algorithm>
30 #include <memory>
31 
32 namespace llvm {
33 
34 class MCContext;
35 class Module;
36 
37 namespace orc {
38 
39 /// Simple compile functor: Takes a single IR module and returns an ObjectFile.
40 /// This compiler supports a single compilation thread and LLVMContext only.
41 /// For multithreaded compilation, use MultiThreadedSimpleCompiler below.
42 class SimpleCompiler {
43 public:
44   using CompileResult = std::unique_ptr<MemoryBuffer>;
45 
46   /// Construct a simple compile functor with the given target.
47   SimpleCompiler(TargetMachine &TM, ObjectCache *ObjCache = nullptr)
TM(TM)48     : TM(TM), ObjCache(ObjCache) {}
49 
50   /// Set an ObjectCache to query before compiling.
setObjectCache(ObjectCache * NewCache)51   void setObjectCache(ObjectCache *NewCache) { ObjCache = NewCache; }
52 
53   /// Compile a Module to an ObjectFile.
operator()54   CompileResult operator()(Module &M) {
55     CompileResult CachedObject = tryToLoadFromObjectCache(M);
56     if (CachedObject)
57       return CachedObject;
58 
59     SmallVector<char, 0> ObjBufferSV;
60 
61     {
62       raw_svector_ostream ObjStream(ObjBufferSV);
63 
64       legacy::PassManager PM;
65       MCContext *Ctx;
66       if (TM.addPassesToEmitMC(PM, Ctx, ObjStream))
67         llvm_unreachable("Target does not support MC emission.");
68       PM.run(M);
69     }
70 
71     auto ObjBuffer =
72         llvm::make_unique<SmallVectorMemoryBuffer>(std::move(ObjBufferSV));
73     auto Obj =
74         object::ObjectFile::createObjectFile(ObjBuffer->getMemBufferRef());
75 
76     if (Obj) {
77       notifyObjectCompiled(M, *ObjBuffer);
78       return std::move(ObjBuffer);
79     }
80 
81     // TODO: Actually report errors helpfully.
82     consumeError(Obj.takeError());
83     return nullptr;
84   }
85 
86 private:
87 
tryToLoadFromObjectCache(const Module & M)88   CompileResult tryToLoadFromObjectCache(const Module &M) {
89     if (!ObjCache)
90       return CompileResult();
91 
92     return ObjCache->getObject(&M);
93   }
94 
notifyObjectCompiled(const Module & M,const MemoryBuffer & ObjBuffer)95   void notifyObjectCompiled(const Module &M, const MemoryBuffer &ObjBuffer) {
96     if (ObjCache)
97       ObjCache->notifyObjectCompiled(&M, ObjBuffer.getMemBufferRef());
98   }
99 
100   TargetMachine &TM;
101   ObjectCache *ObjCache = nullptr;
102 };
103 
104 /// A thread-safe version of SimpleCompiler.
105 ///
106 /// This class creates a new TargetMachine and SimpleCompiler instance for each
107 /// compile.
108 class MultiThreadedSimpleCompiler {
109 public:
110   MultiThreadedSimpleCompiler(JITTargetMachineBuilder JTMB,
111                               ObjectCache *ObjCache = nullptr)
JTMB(std::move (JTMB))112       : JTMB(std::move(JTMB)), ObjCache(ObjCache) {}
113 
setObjectCache(ObjectCache * ObjCache)114   void setObjectCache(ObjectCache *ObjCache) { this->ObjCache = ObjCache; }
115 
operator()116   std::unique_ptr<MemoryBuffer> operator()(Module &M) {
117     auto TM = cantFail(JTMB.createTargetMachine());
118     SimpleCompiler C(*TM, ObjCache);
119     return C(M);
120   }
121 
122 private:
123   JITTargetMachineBuilder JTMB;
124   ObjectCache *ObjCache = nullptr;
125 };
126 
127 } // end namespace orc
128 
129 } // end namespace llvm
130 
131 #endif // LLVM_EXECUTIONENGINE_ORC_COMPILEUTILS_H
132