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/Object/IRObjectFile.h"
22 #include "llvm/Target/TargetMachine.h"
23 #include <string>
24 #include <vector>
25 
26 // Forward references to llvm classes.
27 namespace llvm {
28   class Function;
29   class GlobalValue;
30   class MemoryBuffer;
31   class TargetOptions;
32   class Value;
33 
34 //===----------------------------------------------------------------------===//
35 /// C++ class which implements the opaque lto_module_t type.
36 ///
37 struct LTOModule {
38 private:
39   struct NameAndAttributes {
40     const char        *name;
41     uint32_t           attributes;
42     bool               isFunction;
43     const GlobalValue *symbol;
44   };
45 
46   std::unique_ptr<LLVMContext> OwnedContext;
47 
48   std::string LinkerOpts;
49 
50   std::unique_ptr<object::IRObjectFile> IRFile;
51   std::unique_ptr<TargetMachine> _target;
52   std::vector<NameAndAttributes> _symbols;
53 
54   // _defines and _undefines only needed to disambiguate tentative definitions
55   StringSet<>                             _defines;
56   StringMap<NameAndAttributes> _undefines;
57   std::vector<const char*>                _asm_undefines;
58 
59   LTOModule(std::unique_ptr<object::IRObjectFile> Obj, TargetMachine *TM);
60 
61 public:
62   ~LTOModule();
63 
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 Module is produced for ThinLTO.
69   bool isThinLTO();
70 
71   /// Returns 'true' if the memory buffer is LLVM bitcode for the specified
72   /// triple.
73   static bool isBitcodeForTarget(MemoryBuffer *memBuffer,
74                                  StringRef triplePrefix);
75 
76   /// Returns a string representing the producer identification stored in the
77   /// bitcode, or "" if the bitcode does not contains any.
78   ///
79   static std::string getProducerString(MemoryBuffer *Buffer);
80 
81   /// Create a MemoryBuffer from a memory range with an optional name.
82   static std::unique_ptr<MemoryBuffer>
83   makeBuffer(const void *mem, size_t length, StringRef name = "");
84 
85   /// Create an LTOModule. N.B. These methods take ownership of the buffer. The
86   /// caller must have initialized the Targets, the TargetMCs, the AsmPrinters,
87   /// and the AsmParsers by calling:
88   ///
89   /// InitializeAllTargets();
90   /// InitializeAllTargetMCs();
91   /// InitializeAllAsmPrinters();
92   /// InitializeAllAsmParsers();
93   static ErrorOr<std::unique_ptr<LTOModule>>
94   createFromFile(LLVMContext &Context, const char *path,
95                  const TargetOptions &options);
96   static ErrorOr<std::unique_ptr<LTOModule>>
97   createFromOpenFile(LLVMContext &Context, int fd, const char *path,
98                      size_t size, const 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,
102                           const TargetOptions &options);
103   static ErrorOr<std::unique_ptr<LTOModule>>
104   createFromBuffer(LLVMContext &Context, const void *mem, size_t length,
105                    const TargetOptions &options, StringRef path = "");
106   static ErrorOr<std::unique_ptr<LTOModule>>
107   createInLocalContext(std::unique_ptr<LLVMContext> Context, const void *mem,
108                        size_t length, const TargetOptions &options,
109                        StringRef path);
110 
getModuleLTOModule111   const Module &getModule() const {
112     return const_cast<LTOModule*>(this)->getModule();
113   }
getModuleLTOModule114   Module &getModule() {
115     return IRFile->getModule();
116   }
117 
takeModuleLTOModule118   std::unique_ptr<Module> takeModule() { return IRFile->takeModule(); }
119 
120   /// Return the Module's target triple.
getTargetTripleLTOModule121   const std::string &getTargetTriple() {
122     return getModule().getTargetTriple();
123   }
124 
125   /// Set the Module's target triple.
setTargetTripleLTOModule126   void setTargetTriple(StringRef Triple) {
127     getModule().setTargetTriple(Triple);
128   }
129 
130   /// Get the number of symbols
getSymbolCountLTOModule131   uint32_t getSymbolCount() {
132     return _symbols.size();
133   }
134 
135   /// Get the attributes for a symbol at the specified index.
getSymbolAttributesLTOModule136   lto_symbol_attributes getSymbolAttributes(uint32_t index) {
137     if (index < _symbols.size())
138       return lto_symbol_attributes(_symbols[index].attributes);
139     return lto_symbol_attributes(0);
140   }
141 
142   /// Get the name of the symbol at the specified index.
getSymbolNameLTOModule143   const char *getSymbolName(uint32_t index) {
144     if (index < _symbols.size())
145       return _symbols[index].name;
146     return nullptr;
147   }
148 
getSymbolGVLTOModule149   const GlobalValue *getSymbolGV(uint32_t index) {
150     if (index < _symbols.size())
151       return _symbols[index].symbol;
152     return nullptr;
153   }
154 
getLinkerOptsLTOModule155   const char *getLinkerOpts() {
156     return LinkerOpts.c_str();
157   }
158 
getAsmUndefinedRefsLTOModule159   const std::vector<const char*> &getAsmUndefinedRefs() {
160     return _asm_undefines;
161   }
162 
163 private:
164   /// Parse metadata from the module
165   // FIXME: it only parses "Linker Options" metadata at the moment
166   void parseMetadata();
167 
168   /// Parse the symbols from the module and model-level ASM and add them to
169   /// either the defined or undefined lists.
170   void parseSymbols();
171 
172   /// Add a symbol which isn't defined just yet to a list to be resolved later.
173   void addPotentialUndefinedSymbol(const object::BasicSymbolRef &Sym,
174                                    bool isFunc);
175 
176   /// Add a defined symbol to the list.
177   void addDefinedSymbol(const char *Name, const GlobalValue *def,
178                         bool isFunction);
179 
180   /// Add a data symbol as defined to the list.
181   void addDefinedDataSymbol(const object::BasicSymbolRef &Sym);
182   void addDefinedDataSymbol(const char*Name, const GlobalValue *v);
183 
184   /// Add a function symbol as defined to the list.
185   void addDefinedFunctionSymbol(const object::BasicSymbolRef &Sym);
186   void addDefinedFunctionSymbol(const char *Name, const Function *F);
187 
188   /// Add a global symbol from module-level ASM to the defined list.
189   void addAsmGlobalSymbol(const char *, lto_symbol_attributes scope);
190 
191   /// Add a global symbol from module-level ASM to the undefined list.
192   void addAsmGlobalSymbolUndef(const char *);
193 
194   /// Parse i386/ppc ObjC class data structure.
195   void addObjCClass(const GlobalVariable *clgv);
196 
197   /// Parse i386/ppc ObjC category data structure.
198   void addObjCCategory(const GlobalVariable *clgv);
199 
200   /// Parse i386/ppc ObjC class list data structure.
201   void addObjCClassRef(const GlobalVariable *clgv);
202 
203   /// Get string that the data pointer points to.
204   bool objcClassNameFromExpression(const Constant *c, std::string &name);
205 
206   /// Create an LTOModule (private version).
207   static ErrorOr<std::unique_ptr<LTOModule>>
208   makeLTOModule(MemoryBufferRef Buffer, const TargetOptions &options,
209                 LLVMContext &Context, bool ShouldBeLazy);
210 };
211 }
212 #endif
213