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//
// Copyright 2012-2016 Francisco Jerez
// Copyright 2012-2016 Advanced Micro Devices, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
//
///
/// \file
/// Generate code using an arbitrary LLVM back-end capable of emitting
/// executable code as an ELF object file.
///
#include "llvm/codegen.hpp"
#include "llvm/compat.hpp"
#include "llvm/util.hpp"
#include "core/error.hpp"
#include <llvm/Target/TargetMachine.h>
#include <llvm/Support/TargetRegistry.h>
#include <llvm/Transforms/Utils/Cloning.h>
#include <libelf.h>
#include <gelf.h>
using namespace clover;
using namespace clover::llvm;
using ::llvm::TargetMachine;
namespace {
namespace elf {
std::unique_ptr<Elf, int (*)(Elf *)>
get(const std::vector<char> &code) {
// One of the libelf implementations
// (http://www.mr511.de/software/english.htm) requires calling
// elf_version() before elf_memory().
elf_version(EV_CURRENT);
return { elf_memory(const_cast<char *>(code.data()), code.size()),
elf_end };
}
Elf_Scn *
get_symbol_table(Elf *elf) {
size_t section_str_index;
elf_getshdrstrndx(elf, §ion_str_index);
for (Elf_Scn *s = elf_nextscn(elf, NULL); s; s = elf_nextscn(elf, s)) {
GElf_Shdr header;
if (gelf_getshdr(s, &header) != &header)
return nullptr;
if (!std::strcmp(elf_strptr(elf, section_str_index, header.sh_name),
".symtab"))
return s;
}
return nullptr;
}
std::map<std::string, unsigned>
get_symbol_offsets(Elf *elf, Elf_Scn *symtab) {
Elf_Data *const symtab_data = elf_getdata(symtab, NULL);
GElf_Shdr header;
if (gelf_getshdr(symtab, &header) != &header)
return {};
std::map<std::string, unsigned> symbol_offsets;
GElf_Sym symbol;
unsigned i = 0;
while (GElf_Sym *s = gelf_getsym(symtab_data, i++, &symbol)) {
const char *name = elf_strptr(elf, header.sh_link, s->st_name);
symbol_offsets[name] = s->st_value;
}
return symbol_offsets;
}
}
std::map<std::string, unsigned>
get_symbol_offsets(const std::vector<char> &code, std::string &r_log) {
const auto elf = elf::get(code);
const auto symtab = elf::get_symbol_table(elf.get());
if (!symtab)
fail(r_log, build_error(), "Unable to find symbol table.");
return elf::get_symbol_offsets(elf.get(), symtab);
}
std::vector<char>
emit_code(::llvm::Module &mod, const target &target,
compat::CodeGenFileType ft,
std::string &r_log) {
std::string err;
auto t = ::llvm::TargetRegistry::lookupTarget(target.triple, err);
if (!t)
fail(r_log, build_error(), err);
std::unique_ptr<TargetMachine> tm {
t->createTargetMachine(target.triple, target.cpu, "", {},
::llvm::None, compat::default_code_model,
::llvm::CodeGenOpt::Default) };
if (!tm)
fail(r_log, build_error(),
"Could not create TargetMachine: " + target.triple);
::llvm::SmallVector<char, 1024> data;
{
::llvm::legacy::PassManager pm;
::llvm::raw_svector_ostream os { data };
mod.setDataLayout(tm->createDataLayout());
tm->Options.MCOptions.AsmVerbose =
(ft == compat::CGFT_AssemblyFile);
if (compat::add_passes_to_emit_file(*tm, pm, os, ft))
fail(r_log, build_error(), "TargetMachine can't emit this file");
pm.run(mod);
}
return { data.begin(), data.end() };
}
}
module
clover::llvm::build_module_native(::llvm::Module &mod, const target &target,
const clang::CompilerInstance &c,
std::string &r_log) {
const auto code = emit_code(mod, target,
compat::CGFT_ObjectFile, r_log);
return build_module_common(mod, code, get_symbol_offsets(code, r_log), c);
}
std::string
clover::llvm::print_module_native(const ::llvm::Module &mod,
const target &target) {
std::string log;
try {
std::unique_ptr< ::llvm::Module> cmod { compat::clone_module(mod) };
return as_string(emit_code(*cmod, target,
compat::CGFT_AssemblyFile, log));
} catch (...) {
return "Couldn't output native disassembly: " + log;
}
}
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