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/Linker/Linker.h"
43 #include "llvm/Target/TargetMachine.h"
44 #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();
66 LTOCodeGenerator(std::unique_ptr<LLVMContext> Context);
69 /// Merge given module. Return true on success.
70 bool addModule(struct LTOModule *);
72 /// Set the destination module.
73 void setModule(std::unique_ptr<LTOModule> M);
75 void setTargetOptions(TargetOptions Options);
76 void setDebugInfo(lto_debug_model);
77 void setCodePICModel(Reloc::Model Model) { RelocModel = Model; }
79 /// Set the file type to be emitted (assembly or object code).
80 /// The default is TargetMachine::CGFT_ObjectFile.
81 void setFileType(TargetMachine::CodeGenFileType FT) { FileType = FT; }
83 void setCpu(const char *MCpu) { this->MCpu = MCpu; }
84 void setAttr(const char *MAttr) { this->MAttr = MAttr; }
85 void setOptLevel(unsigned OptLevel);
87 void setShouldInternalize(bool Value) { ShouldInternalize = Value; }
88 void setShouldEmbedUselists(bool Value) { ShouldEmbedUselists = Value; }
90 void addMustPreserveSymbol(StringRef Sym) { MustPreserveSymbols[Sym] = 1; }
92 /// Pass options to the driver and optimization passes.
94 /// These options are not necessarily for debugging purpose (the function
95 /// name is misleading). This function should be called before
96 /// LTOCodeGenerator::compilexxx(), and
97 /// LTOCodeGenerator::writeMergedModules().
98 void setCodeGenDebugOptions(const char *Opts);
100 /// Parse the options set in setCodeGenDebugOptions.
102 /// Like \a setCodeGenDebugOptions(), this must be called before
103 /// LTOCodeGenerator::compilexxx() and
104 /// LTOCodeGenerator::writeMergedModules().
105 void parseCodeGenDebugOptions();
107 /// Write the merged module to the file specified by the given path. Return
109 bool writeMergedModules(const char *Path);
111 /// Compile the merged module into a *single* output file; the path to output
112 /// file is returned to the caller via argument "name". Return true on
115 /// \note It is up to the linker to remove the intermediate output file. Do
116 /// not try to remove the object file in LTOCodeGenerator's destructor as we
117 /// don't who (LTOCodeGenerator or the output file) will last longer.
118 bool compile_to_file(const char **Name, bool DisableVerify,
119 bool DisableInline, bool DisableGVNLoadPRE,
120 bool DisableVectorization);
122 /// As with compile_to_file(), this function compiles the merged module into
123 /// single output file. Instead of returning the output file path to the
124 /// caller (linker), it brings the output to a buffer, and returns the buffer
125 /// to the caller. This function should delete the intermediate file once
126 /// its content is brought to memory. Return NULL if the compilation was not
128 std::unique_ptr<MemoryBuffer> compile(bool DisableVerify, bool DisableInline,
129 bool DisableGVNLoadPRE,
130 bool DisableVectorization);
132 /// Optimizes the merged module. Returns true on success.
133 bool optimize(bool DisableVerify, bool DisableInline, bool DisableGVNLoadPRE,
134 bool DisableVectorization);
136 /// Compiles the merged optimized module into a single output file. It brings
137 /// the output to a buffer, and returns the buffer to the caller. Return NULL
138 /// if the compilation was not successful.
139 std::unique_ptr<MemoryBuffer> compileOptimized();
141 /// Compile the merged optimized module into out.size() output files each
142 /// representing a linkable partition of the module. If out contains more
143 /// than one element, code generation is done in parallel with out.size()
144 /// threads. Output files will be written to members of out. Returns true on
146 bool compileOptimized(ArrayRef<raw_pwrite_stream *> Out);
148 void setDiagnosticHandler(lto_diagnostic_handler_t, void *);
150 LLVMContext &getContext() { return Context; }
153 void initializeLTOPasses();
155 bool compileOptimizedToFile(const char **Name);
156 void applyScopeRestrictions();
157 void applyRestriction(GlobalValue &GV, ArrayRef<StringRef> Libcalls,
158 std::vector<const char *> &MustPreserveList,
159 SmallPtrSetImpl<GlobalValue *> &AsmUsed,
161 bool determineTarget();
163 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
165 void DiagnosticHandler2(const DiagnosticInfo &DI);
167 void emitError(const std::string &ErrMsg);
169 typedef StringMap<uint8_t> StringSet;
171 std::unique_ptr<LLVMContext> OwnedContext;
172 LLVMContext &Context;
173 std::unique_ptr<Module> MergedModule;
175 std::unique_ptr<TargetMachine> TargetMach;
176 bool EmitDwarfDebugInfo = false;
177 bool ScopeRestrictionsDone = false;
178 Reloc::Model RelocModel = Reloc::Default;
179 StringSet MustPreserveSymbols;
180 StringSet AsmUndefinedRefs;
181 std::vector<std::string> CodegenOptions;
182 std::string FeatureStr;
185 std::string NativeObjectPath;
186 TargetOptions Options;
187 CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
188 unsigned OptLevel = 2;
189 lto_diagnostic_handler_t DiagHandler = nullptr;
190 void *DiagContext = nullptr;
191 bool ShouldInternalize = true;
192 bool ShouldEmbedUselists = false;
193 TargetMachine::CodeGenFileType FileType = TargetMachine::CGFT_ObjectFile;