1 //===-LTOCodeGenerator.h - LLVM Link Time Optimizer -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the LTOCodeGenerator class.
12 // LTO compilation consists of three phases: Pre-IPO, IPO and Post-IPO.
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
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).
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()).
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.
33 //===----------------------------------------------------------------------===//
35 #ifndef LLVM_LTO_LTOCODEGENERATOR_H
36 #define LLVM_LTO_LTOCODEGENERATOR_H
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/Target/TargetMachine.h"
43 #include "llvm/Target/TargetOptions.h"
54 class TargetLibraryInfo;
57 class raw_pwrite_stream;
59 //===----------------------------------------------------------------------===//
60 /// C++ class which implements the opaque lto_code_gen_t type.
62 struct LTOCodeGenerator {
63 static const char *getVersionString();
65 LTOCodeGenerator(LLVMContext &Context);
68 /// Merge given module. Return true on success.
69 bool addModule(struct LTOModule *);
71 /// Set the destination module.
72 void setModule(std::unique_ptr<LTOModule> M);
74 void setTargetOptions(TargetOptions Options);
75 void setDebugInfo(lto_debug_model);
76 void setCodePICModel(Reloc::Model Model) { RelocModel = Model; }
78 /// Set the file type to be emitted (assembly or object code).
79 /// The default is TargetMachine::CGFT_ObjectFile.
80 void setFileType(TargetMachine::CodeGenFileType FT) { FileType = FT; }
82 void setCpu(const char *MCpu) { this->MCpu = MCpu; }
83 void setAttr(const char *MAttr) { this->MAttr = MAttr; }
84 void setOptLevel(unsigned OptLevel);
86 void setShouldInternalize(bool Value) { ShouldInternalize = Value; }
87 void setShouldEmbedUselists(bool Value) { ShouldEmbedUselists = Value; }
89 void addMustPreserveSymbol(StringRef Sym) { MustPreserveSymbols[Sym] = 1; }
91 /// Pass options to the driver and optimization passes.
93 /// These options are not necessarily for debugging purpose (the function
94 /// name is misleading). This function should be called before
95 /// LTOCodeGenerator::compilexxx(), and
96 /// LTOCodeGenerator::writeMergedModules().
97 void setCodeGenDebugOptions(const char *Opts);
99 /// Parse the options set in setCodeGenDebugOptions.
101 /// Like \a setCodeGenDebugOptions(), this must be called before
102 /// LTOCodeGenerator::compilexxx() and
103 /// LTOCodeGenerator::writeMergedModules().
104 void parseCodeGenDebugOptions();
106 /// Write the merged module to the file specified by the given path. Return
108 bool writeMergedModules(const char *Path);
110 /// Compile the merged module into a *single* output file; the path to output
111 /// file is returned to the caller via argument "name". Return true on
114 /// \note It is up to the linker to remove the intermediate output file. Do
115 /// not try to remove the object file in LTOCodeGenerator's destructor as we
116 /// don't who (LTOCodeGenerator or the output file) will last longer.
117 bool compile_to_file(const char **Name, bool DisableVerify,
118 bool DisableInline, bool DisableGVNLoadPRE,
119 bool DisableVectorization);
121 /// As with compile_to_file(), this function compiles the merged module into
122 /// single output file. Instead of returning the output file path to the
123 /// caller (linker), it brings the output to a buffer, and returns the buffer
124 /// to the caller. This function should delete the intermediate file once
125 /// its content is brought to memory. Return NULL if the compilation was not
127 std::unique_ptr<MemoryBuffer> compile(bool DisableVerify, bool DisableInline,
128 bool DisableGVNLoadPRE,
129 bool DisableVectorization);
131 /// Optimizes the merged module. Returns true on success.
132 bool optimize(bool DisableVerify, bool DisableInline, bool DisableGVNLoadPRE,
133 bool DisableVectorization);
135 /// Compiles the merged optimized module into a single output file. It brings
136 /// the output to a buffer, and returns the buffer to the caller. Return NULL
137 /// if the compilation was not successful.
138 std::unique_ptr<MemoryBuffer> compileOptimized();
140 /// Compile the merged optimized module into out.size() output files each
141 /// representing a linkable partition of the module. If out contains more
142 /// than one element, code generation is done in parallel with out.size()
143 /// threads. Output files will be written to members of out. Returns true on
145 bool compileOptimized(ArrayRef<raw_pwrite_stream *> Out);
147 void setDiagnosticHandler(lto_diagnostic_handler_t, void *);
149 LLVMContext &getContext() { return Context; }
152 void initializeLTOPasses();
154 bool compileOptimizedToFile(const char **Name);
155 void applyScopeRestrictions();
156 void applyRestriction(GlobalValue &GV, ArrayRef<StringRef> Libcalls,
157 std::vector<const char *> &MustPreserveList,
158 SmallPtrSetImpl<GlobalValue *> &AsmUsed,
160 bool determineTarget();
162 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
164 void DiagnosticHandler2(const DiagnosticInfo &DI);
166 void emitError(const std::string &ErrMsg);
168 typedef StringMap<uint8_t> StringSet;
170 LLVMContext &Context;
171 std::unique_ptr<Module> MergedModule;
172 std::unique_ptr<Linker> IRLinker;
173 std::unique_ptr<TargetMachine> TargetMach;
174 bool EmitDwarfDebugInfo = false;
175 bool ScopeRestrictionsDone = false;
176 Reloc::Model RelocModel = Reloc::Default;
177 StringSet MustPreserveSymbols;
178 StringSet AsmUndefinedRefs;
179 std::vector<std::string> CodegenOptions;
180 std::string FeatureStr;
183 std::string NativeObjectPath;
184 TargetOptions Options;
185 CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
186 unsigned OptLevel = 2;
187 lto_diagnostic_handler_t DiagHandler = nullptr;
188 void *DiagContext = nullptr;
189 bool ShouldInternalize = true;
190 bool ShouldEmbedUselists = false;
191 TargetMachine::CodeGenFileType FileType = TargetMachine::CGFT_ObjectFile;