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1 //===-LTOModule.h - LLVM Link Time Optimizer ------------------------------===//
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 the LTOModule class.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LTO_LTOMODULE_H
15 #define LLVM_LTO_LTOMODULE_H
16 
17 #include "llvm-c/lto.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/ADT/StringSet.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCObjectFileInfo.h"
23 #include "llvm/Object/IRObjectFile.h"
24 #include "llvm/Target/TargetMachine.h"
25 #include <string>
26 #include <vector>
27 
28 // Forward references to llvm classes.
29 namespace llvm {
30   class Function;
31   class GlobalValue;
32   class MemoryBuffer;
33   class TargetOptions;
34   class Value;
35 
36 //===----------------------------------------------------------------------===//
37 /// C++ class which implements the opaque lto_module_t type.
38 ///
39 struct LTOModule {
40 private:
41   struct NameAndAttributes {
42     const char        *name;
43     uint32_t           attributes;
44     bool               isFunction;
45     const GlobalValue *symbol;
46   };
47 
48   std::unique_ptr<LLVMContext> OwnedContext;
49 
50   std::string LinkerOpts;
51 
52   std::unique_ptr<object::IRObjectFile> IRFile;
53   std::unique_ptr<TargetMachine> _target;
54   std::vector<NameAndAttributes> _symbols;
55 
56   // _defines and _undefines only needed to disambiguate tentative definitions
57   StringSet<>                             _defines;
58   StringMap<NameAndAttributes> _undefines;
59   std::vector<const char*>                _asm_undefines;
60 
61   LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM);
62   LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM,
63             std::unique_ptr<LLVMContext> Context);
64 
65 public:
66   ~LTOModule();
67 
68   /// Returns 'true' if the file or memory contents is LLVM bitcode.
69   static bool isBitcodeFile(const void *mem, size_t length);
70   static bool isBitcodeFile(const char *path);
71 
72   /// Returns 'true' if the memory buffer is LLVM bitcode for the specified
73   /// triple.
74   static bool isBitcodeForTarget(MemoryBuffer *memBuffer,
75                                  StringRef triplePrefix);
76 
77   /// Returns a string representing the producer identification stored in the
78   /// bitcode, or "" if the bitcode does not contains any.
79   ///
80   static std::string getProducerString(MemoryBuffer *Buffer);
81 
82   /// Create a MemoryBuffer from a memory range with an optional name.
83   static std::unique_ptr<MemoryBuffer>
84   makeBuffer(const void *mem, size_t length, StringRef name = "");
85 
86   /// Create an LTOModule. N.B. These methods take ownership of the buffer. The
87   /// caller must have initialized the Targets, the TargetMCs, the AsmPrinters,
88   /// and the AsmParsers by calling:
89   ///
90   /// InitializeAllTargets();
91   /// InitializeAllTargetMCs();
92   /// InitializeAllAsmPrinters();
93   /// InitializeAllAsmParsers();
94   static ErrorOr<std::unique_ptr<LTOModule>>
95   createFromFile(LLVMContext &Context, const char *path, TargetOptions options);
96   static ErrorOr<std::unique_ptr<LTOModule>>
97   createFromOpenFile(LLVMContext &Context, int fd, const char *path,
98                      size_t size, TargetOptions options);
99   static ErrorOr<std::unique_ptr<LTOModule>>
100   createFromOpenFileSlice(LLVMContext &Context, int fd, const char *path,
101                           size_t map_size, off_t offset, TargetOptions options);
102   static ErrorOr<std::unique_ptr<LTOModule>>
103   createFromBuffer(LLVMContext &Context, const void *mem, size_t length,
104                    TargetOptions options, StringRef path = "");
105 
106   static ErrorOr<std::unique_ptr<LTOModule>>
107   createInLocalContext(const void *mem, size_t length, TargetOptions options,
108                        StringRef path);
109   static ErrorOr<std::unique_ptr<LTOModule>>
110   createInContext(const void *mem, size_t length, TargetOptions options,
111                   StringRef path, LLVMContext *Context);
112 
getModuleLTOModule113   const Module &getModule() const {
114     return const_cast<LTOModule*>(this)->getModule();
115   }
getModuleLTOModule116   Module &getModule() {
117     return IRFile->getModule();
118   }
119 
takeModuleLTOModule120   std::unique_ptr<Module> takeModule() { return IRFile->takeModule(); }
121 
122   /// Return the Module's target triple.
getTargetTripleLTOModule123   const std::string &getTargetTriple() {
124     return getModule().getTargetTriple();
125   }
126 
127   /// Set the Module's target triple.
setTargetTripleLTOModule128   void setTargetTriple(StringRef Triple) {
129     getModule().setTargetTriple(Triple);
130   }
131 
132   /// Get the number of symbols
getSymbolCountLTOModule133   uint32_t getSymbolCount() {
134     return _symbols.size();
135   }
136 
137   /// Get the attributes for a symbol at the specified index.
getSymbolAttributesLTOModule138   lto_symbol_attributes getSymbolAttributes(uint32_t index) {
139     if (index < _symbols.size())
140       return lto_symbol_attributes(_symbols[index].attributes);
141     return lto_symbol_attributes(0);
142   }
143 
144   /// Get the name of the symbol at the specified index.
getSymbolNameLTOModule145   const char *getSymbolName(uint32_t index) {
146     if (index < _symbols.size())
147       return _symbols[index].name;
148     return nullptr;
149   }
150 
getSymbolGVLTOModule151   const GlobalValue *getSymbolGV(uint32_t index) {
152     if (index < _symbols.size())
153       return _symbols[index].symbol;
154     return nullptr;
155   }
156 
getLinkerOptsLTOModule157   const char *getLinkerOpts() {
158     return LinkerOpts.c_str();
159   }
160 
getAsmUndefinedRefsLTOModule161   const std::vector<const char*> &getAsmUndefinedRefs() {
162     return _asm_undefines;
163   }
164 
165 private:
166   /// Parse metadata from the module
167   // FIXME: it only parses "Linker Options" metadata at the moment
168   void parseMetadata();
169 
170   /// Parse the symbols from the module and model-level ASM and add them to
171   /// either the defined or undefined lists.
172   void parseSymbols();
173 
174   /// Add a symbol which isn't defined just yet to a list to be resolved later.
175   void addPotentialUndefinedSymbol(const object::BasicSymbolRef &Sym,
176                                    bool isFunc);
177 
178   /// Add a defined symbol to the list.
179   void addDefinedSymbol(const char *Name, const GlobalValue *def,
180                         bool isFunction);
181 
182   /// Add a data symbol as defined to the list.
183   void addDefinedDataSymbol(const object::BasicSymbolRef &Sym);
184   void addDefinedDataSymbol(const char*Name, const GlobalValue *v);
185 
186   /// Add a function symbol as defined to the list.
187   void addDefinedFunctionSymbol(const object::BasicSymbolRef &Sym);
188   void addDefinedFunctionSymbol(const char *Name, const Function *F);
189 
190   /// Add a global symbol from module-level ASM to the defined list.
191   void addAsmGlobalSymbol(const char *, lto_symbol_attributes scope);
192 
193   /// Add a global symbol from module-level ASM to the undefined list.
194   void addAsmGlobalSymbolUndef(const char *);
195 
196   /// Parse i386/ppc ObjC class data structure.
197   void addObjCClass(const GlobalVariable *clgv);
198 
199   /// Parse i386/ppc ObjC category data structure.
200   void addObjCCategory(const GlobalVariable *clgv);
201 
202   /// Parse i386/ppc ObjC class list data structure.
203   void addObjCClassRef(const GlobalVariable *clgv);
204 
205   /// Get string that the data pointer points to.
206   bool objcClassNameFromExpression(const Constant *c, std::string &name);
207 
208   /// Create an LTOModule (private version).
209   static ErrorOr<std::unique_ptr<LTOModule>>
210   makeLTOModule(MemoryBufferRef Buffer, TargetOptions options,
211                 LLVMContext *Context);
212 };
213 }
214 #endif
215