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(struct LTOModule *);
74 void setTargetOptions(TargetOptions options);
75 void setDebugInfo(lto_debug_model);
76 void setCodePICModel(lto_codegen_model);
78 void setCpu(const char *mCpu) { MCpu = mCpu; }
79 void setAttr(const char *mAttr) { MAttr = mAttr; }
80 void setOptLevel(unsigned optLevel) { OptLevel = optLevel; }
82 void addMustPreserveSymbol(const char *sym) { MustPreserveSymbols[sym] = 1; }
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);
90 // Parse the options set in setCodeGenDebugOptions. Like
91 // setCodeGenDebugOptions, this must be called before
92 // LTOCodeGenerator::compilexxx() and LTOCodeGenerator::writeMergedModules()
93 void parseCodeGenDebugOptions();
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);
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
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,
108 bool disableGVNLoadPRE,
109 bool disableVectorization,
110 std::string &errMsg);
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,
119 bool disableGVNLoadPRE,
120 bool disableVectorization,
121 std::string &errMsg);
123 // Optimizes the merged module. Returns true on success.
124 bool optimize(bool disableInline,
125 bool disableGVNLoadPRE,
126 bool disableVectorization,
127 std::string &errMsg);
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);
134 void setDiagnosticHandler(lto_diagnostic_handler_t, void *);
136 LLVMContext &getContext() { return Context; }
139 void initializeLTOPasses();
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,
148 bool determineTarget(std::string &errMsg);
150 static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
152 void DiagnosticHandler2(const DiagnosticInfo &DI);
154 typedef StringMap<uint8_t> StringSet;
157 void destroyMergedModule();
158 std::unique_ptr<LLVMContext> OwnedContext;
159 LLVMContext &Context;
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;
171 std::string NativeObjectPath;
172 TargetOptions Options;
174 lto_diagnostic_handler_t DiagHandler;
176 LTOModule *OwnedModule;