//===- ELFEmulation.cpp ---------------------------------------------------===//
//
//                     The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <mcld/Target/ELFEmulation.h>
#include <mcld/LinkerScript.h>
#include <mcld/LinkerConfig.h>
#include <mcld/Script/InputSectDesc.h>

#include <llvm/Support/Host.h>

using namespace mcld;

struct NameMap {
  const char* from; ///< the prefix of the input string. (match FROM*)
  const char* to;   ///< the output string.
  InputSectDesc::KeepPolicy policy; /// mark whether the input is kept in GC
};

static const NameMap map[] =
{
  {".text*", ".text", InputSectDesc::NoKeep},
  {".rodata*", ".rodata", InputSectDesc::NoKeep},
  {".data.rel.ro.local*", ".data.rel.ro.local", InputSectDesc::NoKeep},
  {".data.rel.ro*", ".data.rel.ro", InputSectDesc::NoKeep},
  {".data*", ".data", InputSectDesc::NoKeep},
  {".bss*", ".bss", InputSectDesc::NoKeep},
  {".tdata*", ".tdata", InputSectDesc::NoKeep},
  {".tbss*", ".tbss", InputSectDesc::NoKeep},
  {".init", ".init", InputSectDesc::Keep},
  {".fini", ".fini", InputSectDesc::Keep},
  {".preinit_array*", ".preinit_array", InputSectDesc::Keep},
  {".init_array*", ".init_array", InputSectDesc::Keep},
  {".fini_array*", ".fini_array", InputSectDesc::Keep},
  // TODO: Support DT_INIT_ARRAY for all constructors?
  {".ctors*", ".ctors", InputSectDesc::Keep},
  {".dtors*", ".dtors", InputSectDesc::Keep},
  {".jcr", ".jcr", InputSectDesc::Keep},
  // FIXME: in GNU ld, if we are creating a shared object .sdata2 and .sbss2
  // sections would be handled differently.
  {".sdata2*", ".sdata", InputSectDesc::NoKeep},
  {".sbss2*", ".sbss", InputSectDesc::NoKeep},
  {".sdata*", ".sdata", InputSectDesc::NoKeep},
  {".sbss*", ".sbss", InputSectDesc::NoKeep},
  {".lrodata*", ".lrodata", InputSectDesc::NoKeep},
  {".ldata*", ".ldata", InputSectDesc::NoKeep},
  {".lbss*", ".lbss", InputSectDesc::NoKeep},
  {".gcc_except_table*", ".gcc_except_table", InputSectDesc::Keep},
  {".gnu.linkonce.d.rel.ro.local*", ".data.rel.ro.local", InputSectDesc::NoKeep},
  {".gnu.linkonce.d.rel.ro*", ".data.rel.ro", InputSectDesc::NoKeep},
  {".gnu.linkonce.r*", ".rodata", InputSectDesc::NoKeep},
  {".gnu.linkonce.d*", ".data", InputSectDesc::NoKeep},
  {".gnu.linkonce.b*", ".bss", InputSectDesc::NoKeep},
  {".gnu.linkonce.sb2*", ".sbss", InputSectDesc::NoKeep},
  {".gnu.linkonce.sb*", ".sbss", InputSectDesc::NoKeep},
  {".gnu.linkonce.s2*", ".sdata", InputSectDesc::NoKeep},
  {".gnu.linkonce.s*", ".sdata", InputSectDesc::NoKeep},
  {".gnu.linkonce.wi*", ".debug_info", InputSectDesc::NoKeep},
  {".gnu.linkonce.td*", ".tdata", InputSectDesc::NoKeep},
  {".gnu.linkonce.tb*", ".tbss", InputSectDesc::NoKeep},
  {".gnu.linkonce.t*", ".text", InputSectDesc::NoKeep},
  {".gnu.linkonce.lr*", ".lrodata", InputSectDesc::NoKeep},
  {".gnu.linkonce.lb*", ".lbss", InputSectDesc::NoKeep},
  {".gnu.linkonce.l*", ".ldata", InputSectDesc::NoKeep},
};

bool mcld::MCLDEmulateELF(LinkerScript& pScript, LinkerConfig& pConfig)
// FIXME: LinkerConfig& pConfig should be constant
{
  // set up section map
  if (pConfig.options().getScriptList().empty() &&
      pConfig.codeGenType() != LinkerConfig::Object) {
    const unsigned int map_size =  (sizeof(map) / sizeof(map[0]) );
    for (unsigned int i = 0; i < map_size; ++i) {
      std::pair<SectionMap::mapping, bool> res =
        pScript.sectionMap().insert(map[i].from, map[i].to, map[i].policy);
      if (!res.second)
        return false;
    }
  } else {
    // FIXME: this is the hack to help assignment processing in current
    // implementation.
    pScript.sectionMap().insert("", "");
  }

  if (!pConfig.options().nostdlib()) {
    // TODO: check if user sets the default search path instead via -Y option
    // set up default search path
    switch (pConfig.targets().triple().getOS()) {
      case llvm::Triple::NetBSD:
        pScript.directories().insert("=/usr/lib");
        break;
      case llvm::Triple::MinGW32:
        pScript.directories().insert("=/mingw/lib");
        break;
      default:
        pScript.directories().insert("=/lib");
        pScript.directories().insert("=/usr/lib");
        break;
    }
  }
  return true;
}