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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 LTO_MODULE_H
15 #define LTO_MODULE_H
16 
17 #include "llvm-c/lto.h"
18 #include "llvm/ADT/StringMap.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCObjectFileInfo.h"
22 #include "llvm/Object/IRObjectFile.h"
23 #include "llvm/Target/TargetMachine.h"
24 #include <string>
25 #include <vector>
26 
27 // Forward references to llvm classes.
28 namespace llvm {
29   class Function;
30   class GlobalValue;
31   class MemoryBuffer;
32   class TargetOptions;
33   class Value;
34 
35 //===----------------------------------------------------------------------===//
36 /// C++ class which implements the opaque lto_module_t type.
37 ///
38 struct LTOModule {
39 private:
40   typedef StringMap<uint8_t> StringSet;
41 
42   struct NameAndAttributes {
43     const char        *name;
44     uint32_t           attributes;
45     bool               isFunction;
46     const GlobalValue *symbol;
47   };
48 
49   std::unique_ptr<object::IRObjectFile> IRFile;
50   std::unique_ptr<TargetMachine> _target;
51   StringSet                               _linkeropt_strings;
52   std::vector<const char *>               _deplibs;
53   std::vector<const char *>               _linkeropts;
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 
63 public:
64   /// Returns 'true' if the file or memory contents is LLVM bitcode.
65   static bool isBitcodeFile(const void *mem, size_t length);
66   static bool isBitcodeFile(const char *path);
67 
68   /// Returns 'true' if the memory buffer is LLVM bitcode for the specified
69   /// triple.
70   static bool isBitcodeForTarget(MemoryBuffer *memBuffer,
71                                  StringRef triplePrefix);
72 
73   /// Create a MemoryBuffer from a memory range with an optional name.
74   static MemoryBuffer *makeBuffer(const void *mem, size_t length,
75                                   StringRef name = "");
76 
77   /// Create an LTOModule. N.B. These methods take ownership of the buffer. The
78   /// caller must have initialized the Targets, the TargetMCs, the AsmPrinters,
79   /// and the AsmParsers by calling:
80   ///
81   /// InitializeAllTargets();
82   /// InitializeAllTargetMCs();
83   /// InitializeAllAsmPrinters();
84   /// InitializeAllAsmParsers();
85   static LTOModule *createFromFile(const char *path, TargetOptions options,
86                                    std::string &errMsg);
87   static LTOModule *createFromOpenFile(int fd, const char *path, size_t size,
88                                        TargetOptions options,
89                                        std::string &errMsg);
90   static LTOModule *createFromOpenFileSlice(int fd, const char *path,
91                                             size_t map_size, off_t offset,
92                                             TargetOptions options,
93                                             std::string &errMsg);
94   static LTOModule *createFromBuffer(const void *mem, size_t length,
95                                      TargetOptions options, std::string &errMsg,
96                                      StringRef path = "");
97 
getModuleLTOModule98   const Module &getModule() const {
99     return const_cast<LTOModule*>(this)->getModule();
100   }
getModuleLTOModule101   Module &getModule() {
102     return IRFile->getModule();
103   }
104 
105   /// Return the Module's target triple.
getTargetTripleLTOModule106   const std::string &getTargetTriple() {
107     return getModule().getTargetTriple();
108   }
109 
110   /// Set the Module's target triple.
setTargetTripleLTOModule111   void setTargetTriple(StringRef Triple) {
112     getModule().setTargetTriple(Triple);
113   }
114 
115   /// Get the number of symbols
getSymbolCountLTOModule116   uint32_t getSymbolCount() {
117     return _symbols.size();
118   }
119 
120   /// Get the attributes for a symbol at the specified index.
getSymbolAttributesLTOModule121   lto_symbol_attributes getSymbolAttributes(uint32_t index) {
122     if (index < _symbols.size())
123       return lto_symbol_attributes(_symbols[index].attributes);
124     return lto_symbol_attributes(0);
125   }
126 
127   /// Get the name of the symbol at the specified index.
getSymbolNameLTOModule128   const char *getSymbolName(uint32_t index) {
129     if (index < _symbols.size())
130       return _symbols[index].name;
131     return nullptr;
132   }
133 
134   /// Get the number of dependent libraries
getDependentLibraryCountLTOModule135   uint32_t getDependentLibraryCount() {
136     return _deplibs.size();
137   }
138 
139   /// Get the dependent library at the specified index.
getDependentLibraryLTOModule140   const char *getDependentLibrary(uint32_t index) {
141     if (index < _deplibs.size())
142       return _deplibs[index];
143     return nullptr;
144   }
145 
146   /// Get the number of linker options
getLinkerOptCountLTOModule147   uint32_t getLinkerOptCount() {
148     return _linkeropts.size();
149   }
150 
151   /// Get the linker option at the specified index.
getLinkerOptLTOModule152   const char *getLinkerOpt(uint32_t index) {
153     if (index < _linkeropts.size())
154       return _linkeropts[index];
155     return nullptr;
156   }
157 
getAsmUndefinedRefsLTOModule158   const std::vector<const char*> &getAsmUndefinedRefs() {
159     return _asm_undefines;
160   }
161 
162 private:
163   /// Parse metadata from the module
164   // FIXME: it only parses "Linker Options" metadata at the moment
165   void parseMetadata();
166 
167   /// Parse the symbols from the module and model-level ASM and add them to
168   /// either the defined or undefined lists.
169   bool parseSymbols(std::string &errMsg);
170 
171   /// Add a symbol which isn't defined just yet to a list to be resolved later.
172   void addPotentialUndefinedSymbol(const object::BasicSymbolRef &Sym,
173                                    bool isFunc);
174 
175   /// Add a defined symbol to the list.
176   void addDefinedSymbol(const char *Name, const GlobalValue *def,
177                         bool isFunction);
178 
179   /// Add a data symbol as defined to the list.
180   void addDefinedDataSymbol(const object::BasicSymbolRef &Sym);
181   void addDefinedDataSymbol(const char*Name, const GlobalValue *v);
182 
183   /// Add a function symbol as defined to the list.
184   void addDefinedFunctionSymbol(const object::BasicSymbolRef &Sym);
185   void addDefinedFunctionSymbol(const char *Name, const Function *F);
186 
187   /// Add a global symbol from module-level ASM to the defined list.
188   void addAsmGlobalSymbol(const char *, lto_symbol_attributes scope);
189 
190   /// Add a global symbol from module-level ASM to the undefined list.
191   void addAsmGlobalSymbolUndef(const char *);
192 
193   /// Parse i386/ppc ObjC class data structure.
194   void addObjCClass(const GlobalVariable *clgv);
195 
196   /// Parse i386/ppc ObjC category data structure.
197   void addObjCCategory(const GlobalVariable *clgv);
198 
199   /// Parse i386/ppc ObjC class list data structure.
200   void addObjCClassRef(const GlobalVariable *clgv);
201 
202   /// Get string that the data pointer points to.
203   bool objcClassNameFromExpression(const Constant *c, std::string &name);
204 
205   /// Create an LTOModule (private version). N.B. This method takes ownership of
206   /// the buffer.
207   static LTOModule *makeLTOModule(std::unique_ptr<MemoryBuffer> Buffer,
208                                   TargetOptions options, std::string &errMsg);
209 };
210 }
211 #endif // LTO_MODULE_H
212