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/TargetOptions.h"
53 class TargetLibraryInfo;
56 class raw_pwrite_stream;
58 //===----------------------------------------------------------------------===//
59 /// C++ class which implements the opaque lto_code_gen_t type.
61 struct LTOCodeGenerator {
62 static const char *getVersionString();
65 LTOCodeGenerator(std::unique_ptr<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 void setCpu(const char *MCpu) { this->MCpu = MCpu; }
79 void setAttr(const char *MAttr) { this->MAttr = MAttr; }
80 void setOptLevel(unsigned OptLevel);
82 void setShouldInternalize(bool Value) { ShouldInternalize = Value; }
83 void setShouldEmbedUselists(bool Value) { ShouldEmbedUselists = Value; }
85 void addMustPreserveSymbol(StringRef Sym) { MustPreserveSymbols[Sym] = 1; }
87 /// Pass options to the driver and optimization passes.
89 /// These options are not necessarily for debugging purpose (the function
90 /// name is misleading). This function should be called before
91 /// LTOCodeGenerator::compilexxx(), and
92 /// LTOCodeGenerator::writeMergedModules().
93 void setCodeGenDebugOptions(const char *Opts);
95 /// Parse the options set in setCodeGenDebugOptions.
97 /// Like \a setCodeGenDebugOptions(), this must be called before
98 /// LTOCodeGenerator::compilexxx() and
99 /// LTOCodeGenerator::writeMergedModules().
100 void parseCodeGenDebugOptions();
102 /// Write the merged module to the file specified by the given path. Return
104 bool writeMergedModules(const char *Path, std::string &ErrMsg);
106 /// Compile the merged module into a *single* object file; the path to object
107 /// file is returned to the caller via argument "name". Return true on
110 /// \note It is up to the linker to remove the intermediate object file. Do
111 /// not try to remove the object file in LTOCodeGenerator's destructor as we
112 /// don't who (LTOCodeGenerator or the obj file) will last longer.
113 bool compile_to_file(const char **Name, bool DisableVerify,
114 bool DisableInline, bool DisableGVNLoadPRE,
115 bool DisableVectorization, std::string &ErrMsg);
117 /// As with compile_to_file(), this function compiles the merged module into
118 /// single object file. Instead of returning the object-file-path to the
119 /// caller (linker), it brings the object to a buffer, and return the buffer
120 /// to the caller. This function should delete intermediate object file once
121 /// its content is brought to memory. Return NULL if the compilation was not
123 std::unique_ptr<MemoryBuffer> compile(bool DisableVerify, bool DisableInline,
124 bool DisableGVNLoadPRE,
125 bool DisableVectorization,
126 std::string &errMsg);
128 /// Optimizes the merged module. Returns true on success.
129 bool optimize(bool DisableVerify, bool DisableInline, bool DisableGVNLoadPRE,
130 bool DisableVectorization, std::string &ErrMsg);
132 /// Compiles the merged optimized module into a single object file. It brings
133 /// the object to a buffer, and returns the buffer to the caller. Return NULL
134 /// if the compilation was not successful.
135 std::unique_ptr<MemoryBuffer> compileOptimized(std::string &ErrMsg);
137 /// Compile the merged optimized module into out.size() object files each
138 /// representing a linkable partition of the module. If out contains more
139 /// than one element, code generation is done in parallel with out.size()
140 /// threads. Object files will be written to members of out. Returns true on
142 bool compileOptimized(ArrayRef<raw_pwrite_stream *> Out, std::string &ErrMsg);
144 void setDiagnosticHandler(lto_diagnostic_handler_t, void *);
146 LLVMContext &getContext() { return Context; }
149 void initializeLTOPasses();
151 bool compileOptimizedToFile(const char **Name, std::string &ErrMsg);
152 void applyScopeRestrictions();
153 void applyRestriction(GlobalValue &GV, ArrayRef<StringRef> Libcalls,
154 std::vector<const char *> &MustPreserveList,
155 SmallPtrSetImpl<GlobalValue *> &AsmUsed,
157 bool determineTarget(std::string &ErrMsg);
159 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
161 void DiagnosticHandler2(const DiagnosticInfo &DI);
163 typedef StringMap<uint8_t> StringSet;
165 std::unique_ptr<LLVMContext> OwnedContext;
166 LLVMContext &Context;
167 std::unique_ptr<Module> MergedModule;
169 std::unique_ptr<TargetMachine> TargetMach;
170 bool EmitDwarfDebugInfo = false;
171 bool ScopeRestrictionsDone = false;
172 Reloc::Model RelocModel = Reloc::Default;
173 StringSet MustPreserveSymbols;
174 StringSet AsmUndefinedRefs;
175 std::vector<std::string> CodegenOptions;
176 std::string FeatureStr;
179 std::string NativeObjectPath;
180 TargetOptions Options;
181 CodeGenOpt::Level CGOptLevel = CodeGenOpt::Default;
182 unsigned OptLevel = 2;
183 lto_diagnostic_handler_t DiagHandler = nullptr;
184 void *DiagContext = nullptr;
185 bool ShouldInternalize = true;
186 bool ShouldEmbedUselists = false;