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      1 //===-lto.cpp - LLVM Link Time Optimizer ----------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file implements the Link Time Optimization library. This library is
     11 // intended to be used by linker to optimize code at link time.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "llvm-c/lto.h"
     16 #include "LTOCodeGenerator.h"
     17 #include "LTOModule.h"
     18 #include "llvm-c/Core.h"
     19 
     20 
     21 // Holds most recent error string.
     22 // *** Not thread safe ***
     23 static std::string sLastErrorString;
     24 
     25 /// lto_get_version - Returns a printable string.
     26 extern const char* lto_get_version() {
     27   return LTOCodeGenerator::getVersionString();
     28 }
     29 
     30 /// lto_get_error_message - Returns the last error string or NULL if last
     31 /// operation was successful.
     32 const char* lto_get_error_message() {
     33   return sLastErrorString.c_str();
     34 }
     35 
     36 /// lto_module_is_object_file - Validates if a file is a loadable object file.
     37 bool lto_module_is_object_file(const char* path) {
     38   return LTOModule::isBitcodeFile(path);
     39 }
     40 
     41 /// lto_module_is_object_file_for_target - Validates if a file is a loadable
     42 /// object file compilable for requested target.
     43 bool lto_module_is_object_file_for_target(const char* path,
     44                                           const char* target_triplet_prefix) {
     45   return LTOModule::isBitcodeFileForTarget(path, target_triplet_prefix);
     46 }
     47 
     48 /// lto_module_is_object_file_in_memory - Validates if a buffer is a loadable
     49 /// object file.
     50 bool lto_module_is_object_file_in_memory(const void* mem, size_t length) {
     51   return LTOModule::isBitcodeFile(mem, length);
     52 }
     53 
     54 /// lto_module_is_object_file_in_memory_for_target - Validates if a buffer is a
     55 /// loadable object file compilable for the target.
     56 bool
     57 lto_module_is_object_file_in_memory_for_target(const void* mem,
     58                                             size_t length,
     59                                             const char* target_triplet_prefix) {
     60   return LTOModule::isBitcodeFileForTarget(mem, length, target_triplet_prefix);
     61 }
     62 
     63 /// lto_module_create - Loads an object file from disk. Returns NULL on error
     64 /// (check lto_get_error_message() for details).
     65 lto_module_t lto_module_create(const char* path) {
     66   return LTOModule::makeLTOModule(path, sLastErrorString);
     67 }
     68 
     69 /// lto_module_create_from_fd - Loads an object file from disk. Returns NULL on
     70 /// error (check lto_get_error_message() for details).
     71 lto_module_t lto_module_create_from_fd(int fd, const char *path, size_t size) {
     72   return LTOModule::makeLTOModule(fd, path, size, sLastErrorString);
     73 }
     74 
     75 /// lto_module_create_from_fd_at_offset - Loads an object file from disk.
     76 /// Returns NULL on error (check lto_get_error_message() for details).
     77 lto_module_t lto_module_create_from_fd_at_offset(int fd, const char *path,
     78                                                  size_t file_size,
     79                                                  size_t map_size,
     80                                                  off_t offset) {
     81   return LTOModule::makeLTOModule(fd, path, map_size, offset, sLastErrorString);
     82 }
     83 
     84 /// lto_module_create_from_memory - Loads an object file from memory. Returns
     85 /// NULL on error (check lto_get_error_message() for details).
     86 lto_module_t lto_module_create_from_memory(const void* mem, size_t length) {
     87   return LTOModule::makeLTOModule(mem, length, sLastErrorString);
     88 }
     89 
     90 /// lto_module_dispose - Frees all memory for a module. Upon return the
     91 /// lto_module_t is no longer valid.
     92 void lto_module_dispose(lto_module_t mod) {
     93   delete mod;
     94 }
     95 
     96 /// lto_module_get_target_triple - Returns triplet string which the object
     97 /// module was compiled under.
     98 const char* lto_module_get_target_triple(lto_module_t mod) {
     99   return mod->getTargetTriple();
    100 }
    101 
    102 /// lto_module_set_target_triple - Sets triple string with which the object will
    103 /// be codegened.
    104 void lto_module_set_target_triple(lto_module_t mod, const char *triple) {
    105   return mod->setTargetTriple(triple);
    106 }
    107 
    108 /// lto_module_get_num_symbols - Returns the number of symbols in the object
    109 /// module.
    110 unsigned int lto_module_get_num_symbols(lto_module_t mod) {
    111   return mod->getSymbolCount();
    112 }
    113 
    114 /// lto_module_get_symbol_name - Returns the name of the ith symbol in the
    115 /// object module.
    116 const char* lto_module_get_symbol_name(lto_module_t mod, unsigned int index) {
    117   return mod->getSymbolName(index);
    118 }
    119 
    120 /// lto_module_get_symbol_attribute - Returns the attributes of the ith symbol
    121 /// in the object module.
    122 lto_symbol_attributes lto_module_get_symbol_attribute(lto_module_t mod,
    123                                                       unsigned int index) {
    124   return mod->getSymbolAttributes(index);
    125 }
    126 
    127 /// lto_codegen_create - Instantiates a code generator. Returns NULL if there
    128 /// is an error.
    129 lto_code_gen_t lto_codegen_create(void) {
    130   return new LTOCodeGenerator();
    131 }
    132 
    133 /// lto_codegen_dispose - Frees all memory for a code generator. Upon return the
    134 /// lto_code_gen_t is no longer valid.
    135 void lto_codegen_dispose(lto_code_gen_t cg) {
    136   delete cg;
    137 }
    138 
    139 /// lto_codegen_add_module - Add an object module to the set of modules for
    140 /// which code will be generated. Returns true on error (check
    141 /// lto_get_error_message() for details).
    142 bool lto_codegen_add_module(lto_code_gen_t cg, lto_module_t mod) {
    143   return !cg->addModule(mod, sLastErrorString);
    144 }
    145 
    146 /// lto_codegen_set_debug_model - Sets what if any format of debug info should
    147 /// be generated. Returns true on error (check lto_get_error_message() for
    148 /// details).
    149 bool lto_codegen_set_debug_model(lto_code_gen_t cg, lto_debug_model debug) {
    150   cg->setDebugInfo(debug);
    151   return false;
    152 }
    153 
    154 /// lto_codegen_set_pic_model - Sets what code model to generated. Returns true
    155 /// on error (check lto_get_error_message() for details).
    156 bool lto_codegen_set_pic_model(lto_code_gen_t cg, lto_codegen_model model) {
    157   cg->setCodePICModel(model);
    158   return false;
    159 }
    160 
    161 /// lto_codegen_set_cpu - Sets the cpu to generate code for.
    162 void lto_codegen_set_cpu(lto_code_gen_t cg, const char *cpu) {
    163   return cg->setCpu(cpu);
    164 }
    165 
    166 /// lto_codegen_set_assembler_path - Sets the path to the assembler tool.
    167 void lto_codegen_set_assembler_path(lto_code_gen_t cg, const char *path) {
    168   // In here only for backwards compatibility. We use MC now.
    169 }
    170 
    171 /// lto_codegen_set_assembler_args - Sets extra arguments that libLTO should
    172 /// pass to the assembler.
    173 void lto_codegen_set_assembler_args(lto_code_gen_t cg, const char **args,
    174                                     int nargs) {
    175   // In here only for backwards compatibility. We use MC now.
    176 }
    177 
    178 /// lto_codegen_add_must_preserve_symbol - Adds to a list of all global symbols
    179 /// that must exist in the final generated code. If a function is not listed
    180 /// there, it might be inlined into every usage and optimized away.
    181 void lto_codegen_add_must_preserve_symbol(lto_code_gen_t cg,
    182                                           const char *symbol) {
    183   cg->addMustPreserveSymbol(symbol);
    184 }
    185 
    186 /// lto_codegen_write_merged_modules - Writes a new file at the specified path
    187 /// that contains the merged contents of all modules added so far. Returns true
    188 /// on error (check lto_get_error_message() for details).
    189 bool lto_codegen_write_merged_modules(lto_code_gen_t cg, const char *path) {
    190   return !cg->writeMergedModules(path, sLastErrorString);
    191 }
    192 
    193 /// lto_codegen_compile - Generates code for all added modules into one native
    194 /// object file. On success returns a pointer to a generated mach-o/ELF buffer
    195 /// and length set to the buffer size. The buffer is owned by the lto_code_gen_t
    196 /// object and will be freed when lto_codegen_dispose() is called, or
    197 /// lto_codegen_compile() is called again. On failure, returns NULL (check
    198 /// lto_get_error_message() for details).
    199 const void *lto_codegen_compile(lto_code_gen_t cg, size_t *length) {
    200   return cg->compile(length, sLastErrorString);
    201 }
    202 
    203 /// lto_codegen_compile_to_file - Generates code for all added modules into one
    204 /// native object file. The name of the file is written to name. Returns true on
    205 /// error.
    206 bool lto_codegen_compile_to_file(lto_code_gen_t cg, const char **name) {
    207   return !cg->compile_to_file(name, sLastErrorString);
    208 }
    209 
    210 /// lto_codegen_debug_options - Used to pass extra options to the code
    211 /// generator.
    212 void lto_codegen_debug_options(lto_code_gen_t cg, const char *opt) {
    213   cg->setCodeGenDebugOptions(opt);
    214 }
    215