1 //===-LTOCodeGenerator.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 LTOCodeGenerator class. 11 // 12 // LTO compilation consists of three phases: Pre-IPO, IPO and Post-IPO. 13 // 14 // The Pre-IPO phase compiles source code into bitcode file. The resulting 15 // bitcode files, along with object files and libraries, will be fed to the 16 // linker to through the IPO and Post-IPO phases. By using obj-file extension, 17 // the resulting bitcode file disguises itself as an object file, and therefore 18 // obviates the need of writing a special set of the make-rules only for LTO 19 // compilation. 20 // 21 // The IPO phase perform inter-procedural analyses and optimizations, and 22 // the Post-IPO consists two sub-phases: intra-procedural scalar optimizations 23 // (SOPT), and intra-procedural target-dependent code generator (CG). 24 // 25 // As of this writing, we don't separate IPO and the Post-IPO SOPT. They 26 // are intermingled together, and are driven by a single pass manager (see 27 // PassManagerBuilder::populateLTOPassManager()). 28 // 29 // The "LTOCodeGenerator" is the driver for the IPO and Post-IPO stages. 30 // The "CodeGenerator" here is bit confusing. Don't confuse the "CodeGenerator" 31 // with the machine specific code generator. 32 // 33 //===----------------------------------------------------------------------===// 34 35 #ifndef LLVM_LTO_LTOCODEGENERATOR_H 36 #define LLVM_LTO_LTOCODEGENERATOR_H 37 38 #include "llvm-c/lto.h" 39 #include "llvm/ADT/ArrayRef.h" 40 #include "llvm/ADT/SmallPtrSet.h" 41 #include "llvm/ADT/StringMap.h" 42 #include "llvm/Linker/Linker.h" 43 #include "llvm/Target/TargetOptions.h" 44 #include <string> 45 #include <vector> 46 47 namespace llvm { 48 class LLVMContext; 49 class DiagnosticInfo; 50 class GlobalValue; 51 class Mangler; 52 class MemoryBuffer; 53 class TargetLibraryInfo; 54 class TargetMachine; 55 class raw_ostream; 56 class raw_pwrite_stream; 57 58 //===----------------------------------------------------------------------===// 59 /// C++ class which implements the opaque lto_code_gen_t type. 60 /// 61 struct LTOCodeGenerator { 62 static const char *getVersionString(); 63 64 LTOCodeGenerator(); 65 LTOCodeGenerator(std::unique_ptr<LLVMContext> Context); 66 ~LTOCodeGenerator(); 67 68 // Merge given module, return true on success. 69 bool addModule(struct LTOModule *); 70 71 // Set the destination module. 72 void setModule(struct LTOModule *); 73 74 void setTargetOptions(TargetOptions options); 75 void setDebugInfo(lto_debug_model); 76 void setCodePICModel(lto_codegen_model); 77 78 void setCpu(const char *mCpu) { MCpu = mCpu; } 79 void setAttr(const char *mAttr) { MAttr = mAttr; } 80 void setOptLevel(unsigned optLevel) { OptLevel = optLevel; } 81 82 void addMustPreserveSymbol(const char *sym) { MustPreserveSymbols[sym] = 1; } 83 84 // To pass options to the driver and optimization passes. These options are 85 // not necessarily for debugging purpose (The function name is misleading). 86 // This function should be called before LTOCodeGenerator::compilexxx(), 87 // and LTOCodeGenerator::writeMergedModules(). 88 void setCodeGenDebugOptions(const char *opts); 89 90 // Parse the options set in setCodeGenDebugOptions. Like 91 // setCodeGenDebugOptions, this must be called before 92 // LTOCodeGenerator::compilexxx() and LTOCodeGenerator::writeMergedModules() 93 void parseCodeGenDebugOptions(); 94 95 // Write the merged module to the file specified by the given path. 96 // Return true on success. 97 bool writeMergedModules(const char *path, std::string &errMsg); 98 99 // Compile the merged module into a *single* object file; the path to object 100 // file is returned to the caller via argument "name". Return true on 101 // success. 102 // 103 // NOTE that it is up to the linker to remove the intermediate object file. 104 // Do not try to remove the object file in LTOCodeGenerator's destructor 105 // as we don't who (LTOCodeGenerator or the obj file) will last longer. 106 bool compile_to_file(const char **name, 107 bool disableInline, 108 bool disableGVNLoadPRE, 109 bool disableVectorization, 110 std::string &errMsg); 111 112 // As with compile_to_file(), this function compiles the merged module into 113 // single object file. Instead of returning the object-file-path to the caller 114 // (linker), it brings the object to a buffer, and return the buffer to the 115 // caller. This function should delete intermediate object file once its content 116 // is brought to memory. Return NULL if the compilation was not successful. 117 const void *compile(size_t *length, 118 bool disableInline, 119 bool disableGVNLoadPRE, 120 bool disableVectorization, 121 std::string &errMsg); 122 123 // Optimizes the merged module. Returns true on success. 124 bool optimize(bool disableInline, 125 bool disableGVNLoadPRE, 126 bool disableVectorization, 127 std::string &errMsg); 128 129 // Compiles the merged optimized module into a single object file. It brings 130 // the object to a buffer, and returns the buffer to the caller. Return NULL 131 // if the compilation was not successful. 132 const void *compileOptimized(size_t *length, std::string &errMsg); 133 134 void setDiagnosticHandler(lto_diagnostic_handler_t, void *); 135 136 LLVMContext &getContext() { return Context; } 137 138 private: 139 void initializeLTOPasses(); 140 141 bool compileOptimized(raw_pwrite_stream &out, std::string &errMsg); 142 bool compileOptimizedToFile(const char **name, std::string &errMsg); 143 void applyScopeRestrictions(); 144 void applyRestriction(GlobalValue &GV, ArrayRef<StringRef> Libcalls, 145 std::vector<const char *> &MustPreserveList, 146 SmallPtrSetImpl<GlobalValue *> &AsmUsed, 147 Mangler &Mangler); 148 bool determineTarget(std::string &errMsg); 149 150 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context); 151 152 void DiagnosticHandler2(const DiagnosticInfo &DI); 153 154 typedef StringMap<uint8_t> StringSet; 155 156 void initialize(); 157 void destroyMergedModule(); 158 std::unique_ptr<LLVMContext> OwnedContext; 159 LLVMContext &Context; 160 Linker IRLinker; 161 TargetMachine *TargetMach; 162 bool EmitDwarfDebugInfo; 163 bool ScopeRestrictionsDone; 164 lto_codegen_model CodeModel; 165 StringSet MustPreserveSymbols; 166 StringSet AsmUndefinedRefs; 167 std::unique_ptr<MemoryBuffer> NativeObjectFile; 168 std::vector<char *> CodegenOptions; 169 std::string MCpu; 170 std::string MAttr; 171 std::string NativeObjectPath; 172 TargetOptions Options; 173 unsigned OptLevel; 174 lto_diagnostic_handler_t DiagHandler; 175 void *DiagContext; 176 LTOModule *OwnedModule; 177 }; 178 } 179 #endif 180
