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 LTO_CODE_GENERATOR_H
36 #define LTO_CODE_GENERATOR_H
38 #include "llvm-c/lto.h"
39 #include "llvm/ADT/SmallPtrSet.h"
40 #include "llvm/ADT/StringMap.h"
41 #include "llvm/Linker.h"
54 //===----------------------------------------------------------------------===//
55 /// LTOCodeGenerator - C++ class which implements the opaque lto_code_gen_t
58 struct LTOCodeGenerator {
59 static const char *getVersionString();
64 // Merge given module, return true on success.
65 bool addModule(struct LTOModule*, std::string &errMsg);
67 void setDebugInfo(lto_debug_model);
68 void setCodePICModel(lto_codegen_model);
70 void setCpu(const char *mCpu) { MCpu = mCpu; }
72 void addMustPreserveSymbol(const char *sym) { MustPreserveSymbols[sym] = 1; }
74 // To pass options to the driver and optimization passes. These options are
75 // not necessarily for debugging purpose (The function name is misleading).
76 // This function should be called before LTOCodeGenerator::compilexxx(),
77 // and LTOCodeGenerator::writeMergedModules().
79 void setCodeGenDebugOptions(const char *opts);
81 // Write the merged module to the file specified by the given path.
82 // Return true on success.
83 bool writeMergedModules(const char *path, std::string &errMsg);
85 // Compile the merged module into a *single* object file; the path to object
86 // file is returned to the caller via argument "name". Return true on
89 // NOTE that it is up to the linker to remove the intermediate object file.
90 // Do not try to remove the object file in LTOCodeGenerator's destructor
91 // as we don't who (LTOCodeGenerator or the obj file) will last longer.
93 bool compile_to_file(const char **name, std::string &errMsg);
95 // As with compile_to_file(), this function compiles the merged module into
96 // single object file. Instead of returning the object-file-path to the caller
97 // (linker), it brings the object to a buffer, and return the buffer to the
98 // caller. This function should delete intermediate object file once its content
99 // is brought to memory. Return NULL if the compilation was not successful.
101 const void *compile(size_t *length, std::string &errMsg);
104 void initializeLTOPasses();
106 bool generateObjectFile(llvm::raw_ostream &out, std::string &errMsg);
107 void applyScopeRestrictions();
108 void applyRestriction(llvm::GlobalValue &GV,
109 std::vector<const char*> &MustPreserveList,
110 llvm::SmallPtrSet<llvm::GlobalValue*, 8> &AsmUsed,
111 llvm::Mangler &Mangler);
112 bool determineTarget(std::string &errMsg);
114 typedef llvm::StringMap<uint8_t> StringSet;
116 llvm::LLVMContext &Context;
118 llvm::TargetMachine *TargetMach;
119 bool EmitDwarfDebugInfo;
120 bool ScopeRestrictionsDone;
121 lto_codegen_model CodeModel;
122 StringSet MustPreserveSymbols;
123 StringSet AsmUndefinedRefs;
124 llvm::MemoryBuffer *NativeObjectFile;
125 std::vector<char *> CodegenOptions;
127 std::string NativeObjectPath;
130 #endif // LTO_CODE_GENERATOR_H