src/gallium/frontends/clover/llvm/codegen/native.cpp

   1 //
   2 // Copyright 2012-2016 Francisco Jerez
   3 // Copyright 2012-2016 Advanced Micro Devices, Inc.
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining a
   6 // copy of this software and associated documentation files (the "Software"),
   7 // to deal in the Software without restriction, including without limitation
   8 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9 // and/or sell copies of the Software, and to permit persons to whom the
  10 // Software is furnished to do so, subject to the following conditions:
  11 //
  12 // The above copyright notice and this permission notice shall be included in
  13 // all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18 // THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  19 // OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  20 // ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  21 // OTHER DEALINGS IN THE SOFTWARE.
  22 //
  23
  24 ///
  25 /// \file
  26 /// Generate code using an arbitrary LLVM back-end capable of emitting
  27 /// executable code as an ELF object file.
  28 ///
  29
  30 #include "llvm/codegen.hpp"
  31 #include "llvm/compat.hpp"
  32 #include "llvm/util.hpp"
  33 #include "core/error.hpp"
  34
  35 #include <llvm/Target/TargetMachine.h>
  36 #include <llvm/Support/TargetRegistry.h>
  37 #include <llvm/Transforms/Utils/Cloning.h>
  38
  39 #include <libelf.h>
  40 #include <gelf.h>
  41
  42 using namespace clover;
  43 using namespace clover::llvm;
  44 using ::llvm::TargetMachine;
  45
  46 namespace {
  47    namespace elf {
  48       std::unique_ptr<Elf, int (*)(Elf *)>
  49       get(const std::vector<char> &code) {
  50          // One of the libelf implementations
  51          // (http://www.mr511.de/software/english.htm) requires calling
  52          // elf_version() before elf_memory().
  53          elf_version(EV_CURRENT);
  54          return { elf_memory(const_cast<char *>(code.data()), code.size()),
  55                   elf_end };
  56       }
  57
  58       Elf_Scn *
  59       get_symbol_table(Elf *elf) {
  60          size_t section_str_index;
  61          elf_getshdrstrndx(elf, &section_str_index);
  62
  63          for (Elf_Scn *s = elf_nextscn(elf, NULL); s; s = elf_nextscn(elf, s)) {
  64             GElf_Shdr header;
  65             if (gelf_getshdr(s, &header) != &header)
  66                return nullptr;
  67
  68             if (!std::strcmp(elf_strptr(elf, section_str_index, header.sh_name),
  69                              ".symtab"))
  70                return s;
  71          }
  72
  73          return nullptr;
  74       }
  75
  76       std::map<std::string, unsigned>
  77       get_symbol_offsets(Elf *elf, Elf_Scn *symtab) {
  78          Elf_Data *const symtab_data = elf_getdata(symtab, NULL);
  79          GElf_Shdr header;
  80          if (gelf_getshdr(symtab, &header) != &header)
  81             return {};
  82
  83          std::map<std::string, unsigned> symbol_offsets;
  84          GElf_Sym symbol;
  85          unsigned i = 0;
  86
  87          while (GElf_Sym *s = gelf_getsym(symtab_data, i++, &symbol)) {
  88             const char *name = elf_strptr(elf, header.sh_link, s->st_name);
  89             symbol_offsets[name] = s->st_value;
  90          }
  91
  92          return symbol_offsets;
  93       }
  94    }
  95
  96    std::map<std::string, unsigned>
  97    get_symbol_offsets(const std::vector<char> &code, std::string &r_log) {
  98       const auto elf = elf::get(code);
  99       const auto symtab = elf::get_symbol_table(elf.get());
 100       if (!symtab)
 101          fail(r_log, build_error(), "Unable to find symbol table.");
 102
 103       return elf::get_symbol_offsets(elf.get(), symtab);
 104    }
 105
 106    std::vector<char>
 107    emit_code(::llvm::Module &mod, const target &target,
 108              compat::CodeGenFileType ft,
 109              std::string &r_log) {
 110       std::string err;
 111       auto t = ::llvm::TargetRegistry::lookupTarget(target.triple, err);
 112       if (!t)
 113          fail(r_log, build_error(), err);
 114
 115       std::unique_ptr<TargetMachine> tm {
 116          t->createTargetMachine(target.triple, target.cpu, "", {},
 117                                 ::llvm::None, compat::default_code_model,
 118                                 ::llvm::CodeGenOpt::Default) };
 119       if (!tm)
 120          fail(r_log, build_error(),
 121               "Could not create TargetMachine: " + target.triple);
 122
 123       ::llvm::SmallVector<char, 1024> data;
 124
 125       {
 126          ::llvm::legacy::PassManager pm;
 127          ::llvm::raw_svector_ostream os { data };
 128
 129          mod.setDataLayout(tm->createDataLayout());
 130          tm->Options.MCOptions.AsmVerbose =
 131             (ft == compat::CGFT_AssemblyFile);
 132
 133          if (compat::add_passes_to_emit_file(*tm, pm, os, ft))
 134             fail(r_log, build_error(), "TargetMachine can't emit this file");
 135
 136          pm.run(mod);
 137       }
 138
 139       return { data.begin(), data.end() };
 140    }
 141 }
 142
 143 module
 144 clover::llvm::build_module_native(::llvm::Module &mod, const target &target,
 145                                   const clang::CompilerInstance &c,
 146                                   std::string &r_log) {
 147    const auto code = emit_code(mod, target,
 148                                compat::CGFT_ObjectFile, r_log);
 149    return build_module_common(mod, code, get_symbol_offsets(code, r_log), c);
 150 }
 151
 152 std::string
 153 clover::llvm::print_module_native(const ::llvm::Module &mod,
 154                                   const target &target) {
 155    std::string log;
 156    try {
 157       std::unique_ptr< ::llvm::Module> cmod { compat::clone_module(mod) };
 158       return as_string(emit_code(*cmod, target,
 159                                  compat::CGFT_AssemblyFile, log));
 160    } catch (...) {
 161       return "Couldn't output native disassembly: " + log;
 162    }
 163 }