path: root/rts/linker/PEi386.c

/* --------------------------------------------------------------------------
 * PEi386(+) specifics (Win32 targets)
 * ------------------------------------------------------------------------*/

/* The information for this linker comes from
      Microsoft Portable Executable
      and Common Object File Format Specification
      revision 8.3 February 2013

   It can be found online at:

      https://msdn.microsoft.com/en-us/windows/hardware/gg463119.aspx

   Things move, so if that fails, try searching for it via

      http://www.google.com/search?q=PE+COFF+specification

   The ultimate reference for the PE format is the Winnt.h
   header file that comes with the Platform SDKs; as always,
   implementations will drift wrt their documentation.

   A good background article on the PE format is Matt Pietrek's
   March 1994 article in Microsoft System Journal (MSJ)
   (Vol.9, No. 3): "Peering Inside the PE: A Tour of the
   Win32 Portable Executable File Format." The info in there
   has recently been updated in a two part article in
   MSDN magazine, issues Feb and March 2002,
   "Inside Windows: An In-Depth Look into the Win32 Portable
   Executable File Format"

   John Levine's book "Linkers and Loaders" contains useful
   info on PE too.

   The PE specification doesn't specify how to do the actual
   relocations. For this reason, and because both PE and ELF are
   based on COFF, the relocations for the PEi386+ code is based on
   the ELF relocations for the equivalent relocation type.

   The ELF ABI can be found at

   http://www.x86-64.org/documentation/abi.pdf

   The current code is based on version 0.99.6 - October 2013

   The current GHCi linker supports the following four object file formats:

   * PE/PE+ obj - The normal COFF_ANON_OBJ format which is generated by default
     from Windows compilers

   * PE/PE+ big-obj - The big object format COFF_ANON_BIG_OBJ which extends the
     number of sections to 2^31 and the number of symbols in each section. This
     requires a flag but all Windows compilers can produce it.

   * PE Import format - The import library format defined in the PE standard
     COFF_IMPORT_LIB and commonly has the file extension .lib

   * GNU BFD import format - The import library format defined and used by GNU
     tools. See note below.

   Note [BFD import library]
   ~~~~~~~~~~~~~~~~~~~~~~~~~

   On Windows, compilers don't link directly to dynamic libraries.
   The reason for this is that the exports are not always by symbol, the
   Import Address Table (IAT) also allows exports by ordinal number
   or raw addresses.

   So to solve the linking issue, import libraries were added. Import libraries
   can be seen as a specification of how to link implicitly against a dynamic
   library. As a side note, import libraries are also the mechanism which
   can be used to break mutual dependencies between shared libraries and to
   implement delay loading or override the location of a shared library at
   startup.

   Linkers use these import libraries to populate the IAT of the resulting
   binary. At startup the system dynamic loader processes the IAT entries
   and populates the symbols with the correct addresses.

   Anyway, the Windows PE format specifies a simple and efficient format for
   this: It's essentially a list, saying these X symbols can be found in DLL y.
   Commonly, y is a versioned name. e.g. liby_43.dll. This is an artifact of
   the days when Windows did not support side-by-side assemblies. So the
   solution was to version the DLLs by renaming them to include explicit
   version numbers, and to then use the import libraries to point to the right
   version, having the linker do the leg work.

   The format in the PE specification is commonly named using the suffix .lib.
   Unfortunately, GCC/binutils decided not to implement this format, and instead
   have created their own format. This format is either named using the suffix
   .dll.a or .a depending on the tool that makes them. This format is
   undocumented. However the source of dlltool.c in binutils is pretty handy to
   understant it.

   To understand the implementation in GHC, this is what is important:

   the .idata section group is used to hold this information. An import library
   object file will always have these section groups, but the specific
   configuration depends on what the purpose of the file is. They will also
   never have a CODE or DATA section, though depending on the tool that creates
   them they may have the section headers, which will mostly be empty.

   You have to different possible configuration:

   1) Those that define a redirection. In this case the .idata$7 section will
      contain the name of the actual dll to load. This will be the only content
      of the section. In the symbol table, the last symbol will be the name
      used to refer to the dll in the relocation tables. This name will always
      be in the format "symbol_name_iname", however when refered to, the format
      "_head_symbol_name" is used.

      We record this symbol early on during GetNames and load the dll and use
      the module handle as the symbol address.

   2) Symbol definitions. In this case .idata$6 will contain the symbol to load.
      This is stored in the fixed format of 2-byte ordinals followed by a null
      terminated string with the symbol name. The ordinal is to be used when
      the dll does not export symbols by name. (NOTE: We don't currently
      support this in the runtime linker, but it's easy to add should it be
      needed). The last symbol in the symbol table of the section will contain
      the name symbol which contains the dll name to use to resolve the
      reference.

   As a technicality, this also means that the GCC format will allow us to use
   one library to store references to multiple dlls. This can't be produced by
   dlltool, but it can be combined using ar. This is an important feature
   required for dynamic linking support for GHC. So the runtime linker now
   supports this too.
*/

#include "Rts.h"

#if defined(x86_64_HOST_ARCH)
#define USED_IF_x86_64_HOST_ARCH    /* Nothing */
#else
#define USED_IF_x86_64_HOST_ARCH    STG_UNUSED
#endif

#if defined(mingw32_HOST_OS)

#include "RtsUtils.h"
#include "RtsSymbolInfo.h"
#include "GetEnv.h"
#include "linker/PEi386.h"
#include "LinkerInternals.h"

#include <windows.h>
#include <shfolder.h> /* SHGetFolderPathW */
#include <math.h>
#include <wchar.h>
#include <stdbool.h>
#include <stdint.h>

static uint8_t* cstring_from_COFF_symbol_name(
    uint8_t* name,
    uint8_t* strtab);

#if defined(x86_64_HOST_ARCH)
static size_t makeSymbolExtra_PEi386(
    ObjectCode* oc,
    uint64_t index,
    size_t s,
    SymbolName* symbol);
#endif

static void addDLLHandle(
    pathchar* dll_name,
    HINSTANCE instance);

static bool verifyCOFFHeader(
    uint16_t machine,
    IMAGE_FILE_HEADER *hdr,
    pathchar *fileName);

static bool checkIfDllLoaded(
    HINSTANCE instance);

/* Add ld symbol for PE image base. */
#if defined(__GNUC__)
#define __ImageBase __MINGW_LSYMBOL(_image_base__)
#endif

/* Get the base of the module.       */
/* This symbol is defined by ld.     */
extern IMAGE_DOS_HEADER __ImageBase;
#define __image_base (void*)((HINSTANCE)&__ImageBase)

void initLinker_PEi386()
{
    if (!ghciInsertSymbolTable(WSTR("(GHCi/Ld special symbols)"),
                               symhash, "__image_base__", __image_base, HS_BOOL_TRUE, NULL)) {
        barf("ghciInsertSymbolTable failed");
    }

#if defined(mingw32_HOST_OS)
    addDLLHandle(WSTR("*.exe"), GetModuleHandle(NULL));
   /*
    * Most of these are included by base, but GCC always includes them
    * So lets make sure we always have them too.
    *
    * In most cases they would have been loaded by the
    * addDLLHandle above.
    */
    addDLL(WSTR("msvcrt"));
    addDLL(WSTR("kernel32"));
    addDLL(WSTR("advapi32"));
    addDLL(WSTR("shell32"));
    addDLL(WSTR("user32"));
#endif
}

/* A list thereof. */
static OpenedDLL* opened_dlls = NULL;

/* A list thereof. */
static IndirectAddr* indirects = NULL;

/* Adds a DLL instance to the list of DLLs in which to search for symbols. */
static void addDLLHandle(pathchar* dll_name, HINSTANCE instance) {

    /* At this point, we actually know what was loaded.
       So bail out if it's already been loaded.  */
    if (checkIfDllLoaded(instance))
    {
        return;
    }

    OpenedDLL* o_dll;
    o_dll           = stgMallocBytes( sizeof(OpenedDLL), "addDLLHandle" );
    o_dll->name     = dll_name ? pathdup(dll_name) : NULL;
    o_dll->instance = instance;
    o_dll->next     = opened_dlls;
    opened_dlls     = o_dll;

    /* Now discover the dependencies of dll_name that were
       just loaded in our process space. The reason is we have access to them
       without the user having to explicitly specify them.  */
    PIMAGE_NT_HEADERS header =
        (PIMAGE_NT_HEADERS)((BYTE *)instance +
         ((PIMAGE_DOS_HEADER)instance)->e_lfanew);
    PIMAGE_IMPORT_DESCRIPTOR imports =
        (PIMAGE_IMPORT_DESCRIPTOR)((BYTE *)instance + header->
        OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress);

    bool importTableMissing =
        header->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].Size == 0;

    if (importTableMissing) {
        return;
    }

    /* Ignore these compatibility shims.  */
    const pathchar* ms_dll = WSTR("api-ms-win-");
    const int len = wcslen(ms_dll);

    do {
        pathchar* module = mkPath((char*)(BYTE *)instance + imports->Name);
        HINSTANCE module_instance = GetModuleHandleW(module);
        if (0 != wcsncmp(module, ms_dll, len)
            && module_instance
            && !checkIfDllLoaded(module_instance))
        {
            IF_DEBUG(linker, debugBelch("Loading dependency %" PATH_FMT " -> %" PATH_FMT ".\n", dll_name, module));
            /* Now recursively load dependencies too.  */
            addDLLHandle(module, module_instance);
        }
        stgFree(module);
        imports++;
    } while (imports->Name);
}

static OpenedDLL* findLoadedDll(HINSTANCE instance)
{
    for (OpenedDLL* o_dll = opened_dlls; o_dll != NULL; o_dll = o_dll->next) {
        if (o_dll->instance == instance)
        {
            return o_dll;
        }
    }

    return NULL;
}

static bool checkIfDllLoaded(HINSTANCE instance)
{
    return findLoadedDll (instance) != NULL;
}

void freePreloadObjectFile_PEi386(ObjectCode *oc)
{
    VirtualFree(oc->image - PEi386_IMAGE_OFFSET, 0, MEM_RELEASE);

    IndirectAddr *ia, *ia_next;
    ia = indirects;
    while (ia != NULL) {
        ia_next = ia->next;
        stgFree(ia);
        ia = ia_next;
    }
    indirects = NULL;
}

/*************
 * This function determines what kind of COFF image we are dealing with.
 * This is needed in order to correctly load and verify objects and their
 * sections.
 *************/
COFF_OBJ_TYPE getObjectType ( char* image, pathchar* fileName )
{
    /* {D1BAA1C7-BAEE-4ba9-AF20-FAF66AA4DCB8} */
    static const char header_bigobj_classid[16] =
    {
      0xC7, 0xA1, 0xBA, 0xD1,
      0xEE, 0xBA,
      0xa9, 0x4b,
      0xAF, 0x20,
      0xFA, 0xF6, 0x6A, 0xA4, 0xDC, 0xB8
    };

    WORD machine;
    COFF_OBJ_TYPE ret = COFF_UNKNOWN;
    /* First check if we have an ANON_OBJECT_HEADER signature.  */
    ANON_OBJECT_HEADER* anon = (ANON_OBJECT_HEADER*)image;
    if (   anon->Sig1 == IMAGE_FILE_MACHINE_UNKNOWN
        && anon->Sig2 == IMPORT_OBJECT_HDR_SIG2)
    {
        machine = anon->Machine;
        if (verifyCOFFHeader (machine, NULL, fileName))
        {
            switch (anon->Version)
            {
                case 0:
                    ret = COFF_IMPORT_LIB;
                    break;
                case 1:
                    ret = COFF_ANON_OBJ;
                    break;
                case 2:
                    if (memcmp (&anon->ClassID, header_bigobj_classid, 16) == 0)
                        ret = COFF_ANON_BIG_OBJ;
                    break;
                default:
                    break;
            }
        }
    } else {
        /* If it's not an ANON_OBJECT then try an image file.  */
        IMAGE_FILE_HEADER* img = (IMAGE_FILE_HEADER*)image;
        machine = img->Machine;
        if (verifyCOFFHeader (machine, img, fileName))
            ret = COFF_IMAGE;
    }
    return ret;
}

/*************
 * Retrieve common header information
 *************/
COFF_HEADER_INFO* getHeaderInfo ( ObjectCode* oc )
{
   COFF_OBJ_TYPE coff_type = getObjectType (oc->image, oc->fileName);

   COFF_HEADER_INFO* info
     = stgMallocBytes (sizeof(COFF_HEADER_INFO), "getHeaderInfo");
   memset (info, 0, sizeof(COFF_HEADER_INFO));
   info->type = coff_type;
   switch (coff_type)
   {
       case COFF_IMAGE:
        {
         IMAGE_FILE_HEADER* hdr = (IMAGE_FILE_HEADER*)oc->image;
         info->sizeOfHeader         = sizeof(IMAGE_FILE_HEADER);
         info->sizeOfOptionalHeader = hdr->SizeOfOptionalHeader;
         info->pointerToSymbolTable = hdr->PointerToSymbolTable;
         info->numberOfSymbols      = hdr->NumberOfSymbols;
         info->numberOfSections     = hdr->NumberOfSections;
        }
        break;
       case COFF_ANON_BIG_OBJ:
        {
         ANON_OBJECT_HEADER_BIGOBJ* hdr = (ANON_OBJECT_HEADER_BIGOBJ*)oc->image;
         info->sizeOfHeader         = sizeof(ANON_OBJECT_HEADER_BIGOBJ);
         info->sizeOfOptionalHeader = 0;
         info->pointerToSymbolTable = hdr->PointerToSymbolTable;
         info->numberOfSymbols      = hdr->NumberOfSymbols;
         info->numberOfSections     = hdr->NumberOfSections;
        }
        break;
       default:
        {
         stgFree (info);
         info = NULL;
         errorBelch ("Unknown COFF %d type in getHeaderInfo.", coff_type);
        }
        break;
   }

   return info;
}

/*************
 * Symbol utility functions
 *************/
__attribute__ ((always_inline)) inline
size_t getSymbolSize ( COFF_HEADER_INFO *info )
{
    ASSERT(info);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sizeof_COFF_symbol_ex;
        default:
            return sizeof_COFF_symbol_og;
    }
}

__attribute__ ((always_inline)) inline
int32_t getSymSectionNumber ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.SectionNumber;
        default:
            return sym->og.SectionNumber;
    }
}

__attribute__ ((always_inline)) inline
uint32_t getSymValue ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.Value;
        default:
            return sym->og.Value;
    }
}

__attribute__ ((always_inline)) inline
uint8_t getSymStorageClass ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.StorageClass;
        default:
            return sym->og.StorageClass;
    }
}

__attribute__ ((always_inline)) inline
uint8_t getSymNumberOfAuxSymbols ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.NumberOfAuxSymbols;
        default:
            return sym->og.NumberOfAuxSymbols;
    }
}

__attribute__ ((always_inline)) inline
uint16_t getSymType ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.Type;
        default:
            return sym->og.Type;
    }
}

__attribute__ ((always_inline)) inline
uint8_t* getSymShortName ( COFF_HEADER_INFO *info, COFF_symbol* sym )
{
    ASSERT(info);
    ASSERT(sym);
    switch (info->type)
    {
        case COFF_ANON_BIG_OBJ:
            return sym->ex.N.ShortName;
        default:
            return sym->og.N.ShortName;
    }
}

const char *
addDLL_PEi386( pathchar *dll_name, HINSTANCE *loaded )
{
   /* ------------------- Win32 DLL loader ------------------- */

   pathchar*  buf;
   HINSTANCE  instance;

   IF_DEBUG(linker, debugBelch("addDLL; dll_name = `%" PATH_FMT "'\n", dll_name));

    /* The file name has no suffix (yet) so that we can try
       both foo.dll and foo.drv

      The documentation for LoadLibrary says:
        If no file name extension is specified in the lpFileName
        parameter, the default library extension .dll is
        appended. However, the file name string can include a trailing
        point character (.) to indicate that the module name has no
        extension. */

    size_t bufsize = pathlen(dll_name) + 10;
    buf = stgMallocBytes(bufsize * sizeof(wchar_t), "addDLL");

    /* These are ordered by probability of success and order we'd like them.  */
    const wchar_t *formats[] = { L"%ls.DLL", L"%ls.DRV", L"lib%ls.DLL", L"%ls" };
    const DWORD flags[] = { LOAD_LIBRARY_SEARCH_USER_DIRS | LOAD_LIBRARY_SEARCH_DEFAULT_DIRS, 0 };

    int cFormat, cFlag;
    int flags_start = 1; /* Assume we don't support the new API.  */

    /* Detect if newer API are available, if not, skip the first flags entry.  */
    if (GetProcAddress((HMODULE)LoadLibraryW(L"Kernel32.DLL"), "AddDllDirectory")) {
        flags_start = 0;
    }

    /* Iterate through the possible flags and formats.  */
    for (cFlag = flags_start; cFlag < 2; cFlag++)
    {
        for (cFormat = 0; cFormat < 4; cFormat++)
        {
            snwprintf(buf, bufsize, formats[cFormat], dll_name);
            instance = LoadLibraryExW(buf, NULL, flags[cFlag]);
            if (instance == NULL) {
                if (GetLastError() != ERROR_MOD_NOT_FOUND)
                {
                    goto error;
                }
            }
            else
            {
                break; /* We're done. DLL has been loaded.  */
            }
        }
    }

    /* Check if we managed to load the DLL.  */
    if (instance == NULL) {
        goto error;
    }

    addDLLHandle(buf, instance);
    if (loaded) {
        *loaded = instance;
    }
    stgFree(buf);

    return NULL;

error:
    stgFree(buf);

    char* errormsg = malloc(sizeof(char) * 80);
    snprintf(errormsg, 80, "addDLL: %" PATH_FMT " or dependencies not loaded. (Win32 error %lu)", dll_name, GetLastError());
    /* LoadLibrary failed; return a ptr to the error msg. */
    return errormsg;
}

pathchar* findSystemLibrary_PEi386( pathchar* dll_name )
{
    const unsigned int init_buf_size = 1024;
    unsigned int bufsize             = init_buf_size;
    wchar_t* result = malloc(sizeof(wchar_t) * bufsize);
    DWORD wResult   = SearchPathW(NULL, dll_name, NULL, bufsize, result, NULL);

    if (wResult > bufsize) {
        result  = realloc(result, sizeof(wchar_t) * wResult);
        wResult = SearchPathW(NULL, dll_name, NULL, wResult, result, NULL);
    }


    if (!wResult) {
        free(result);
        return NULL;
    }

    return result;
}

HsPtr addLibrarySearchPath_PEi386(pathchar* dll_path)
{
    HINSTANCE hDLL = LoadLibraryW(L"Kernel32.DLL");
    LPAddDLLDirectory AddDllDirectory = (LPAddDLLDirectory)GetProcAddress((HMODULE)hDLL, "AddDllDirectory");

    HsPtr result = NULL;

    const unsigned int init_buf_size = 4096;
    int bufsize                      = init_buf_size;

    // Make sure the path is an absolute path
    WCHAR* abs_path = malloc(sizeof(WCHAR) * init_buf_size);
    DWORD wResult = GetFullPathNameW(dll_path, bufsize, abs_path, NULL);
    if (!wResult){
        sysErrorBelch("addLibrarySearchPath[GetFullPathNameW]: %" PATH_FMT " (Win32 error %lu)", dll_path, GetLastError());
    }
    else if (wResult > init_buf_size) {
        abs_path = realloc(abs_path, sizeof(WCHAR) * wResult);
        if (!GetFullPathNameW(dll_path, bufsize, abs_path, NULL)) {
            sysErrorBelch("addLibrarySearchPath[GetFullPathNameW]: %" PATH_FMT " (Win32 error %lu)", dll_path, GetLastError());
        }
    }

    if (AddDllDirectory) {
        result = AddDllDirectory(abs_path);
    }
    else
    {
        warnMissingKBLibraryPaths();
        WCHAR* str = malloc(sizeof(WCHAR) * init_buf_size);
        wResult = GetEnvironmentVariableW(L"PATH", str, bufsize);

        if (wResult > init_buf_size) {
            str = realloc(str, sizeof(WCHAR) * wResult);
            bufsize = wResult;
            wResult = GetEnvironmentVariableW(L"PATH", str, bufsize);
            if (!wResult) {
                sysErrorBelch("addLibrarySearchPath[GetEnvironmentVariableW]: %" PATH_FMT " (Win32 error %lu)", dll_path, GetLastError());
            }
        }

        bufsize = wResult + 2 + pathlen(abs_path);
        wchar_t* newPath = malloc(sizeof(wchar_t) * bufsize);

        wcscpy(newPath, abs_path);
        wcscat(newPath, L";");
        wcscat(newPath, str);
        if (!SetEnvironmentVariableW(L"PATH", (LPCWSTR)newPath)) {
            sysErrorBelch("addLibrarySearchPath[SetEnvironmentVariableW]: %" PATH_FMT " (Win32 error %lu)", abs_path, GetLastError());
        }

        free(newPath);
        free(abs_path);

        return str;
    }

    if (!result) {
        sysErrorBelch("addLibrarySearchPath: %" PATH_FMT " (Win32 error %lu)", abs_path, GetLastError());
        free(abs_path);
        return NULL;
    }

    free(abs_path);
    return result;
}

bool removeLibrarySearchPath_PEi386(HsPtr dll_path_index)
{
    bool result = false;

    if (dll_path_index != NULL) {
        HINSTANCE hDLL = LoadLibraryW(L"Kernel32.DLL");
        LPRemoveDLLDirectory RemoveDllDirectory = (LPRemoveDLLDirectory)GetProcAddress((HMODULE)hDLL, "RemoveDllDirectory");

        if (RemoveDllDirectory) {
            result = RemoveDllDirectory(dll_path_index);
            // dll_path_index is now invalid, do not use it after this point.
        }
        else
        {
            warnMissingKBLibraryPaths();
            result = SetEnvironmentVariableW(L"PATH", (LPCWSTR)dll_path_index);
            free(dll_path_index);
        }

        if (!result) {
            sysErrorBelch("removeLibrarySearchPath: (Win32 error %lu)", GetLastError());
            return false;
        }
    }

    return !result;
}


/* We assume file pointer is right at the
   beginning of COFF object.
 */
char *
allocateImageAndTrampolines (
   pathchar* arch_name, char* member_name,
   FILE* f USED_IF_x86_64_HOST_ARCH,
   int size,
   int isThin USED_IF_x86_64_HOST_ARCH)
{
   char* image;
#if defined(x86_64_HOST_ARCH)
   if (!isThin)
   {
       /* PeCoff contains number of symbols right in it's header, so
          we can reserve the room for symbolExtras right here. */
       size_t n;
       /* Minimum header size to read.  */
       const size_t MIN_HEADER_SIZE = sizeof(ANON_OBJECT_HEADER);
       char* tmp = stgMallocBytes (MIN_HEADER_SIZE, "allocateImageAndTrampolines");
       n = fread (tmp, 1, MIN_HEADER_SIZE, f);
       if (n != MIN_HEADER_SIZE) {
           stgFree (tmp);
           errorBelch ("getNumberOfSymbols: error whilst reading `%s' header "
                       "in `%" PATH_FMT "'",
                       member_name, arch_name);
           return NULL;
       }
       fseek(f, -(long int)MIN_HEADER_SIZE, SEEK_CUR);

       COFF_OBJ_TYPE objType = getObjectType (tmp, arch_name);
       stgFree (tmp);
       uint32_t numberOfSymbols = 0;
       switch (objType)
       {
           case COFF_IMAGE:
            {
                IMAGE_FILE_HEADER hdr;
                n = fread (&hdr, 1, sizeof(IMAGE_FILE_HEADER), f);
                if (n != sizeof(IMAGE_FILE_HEADER))
                {
                  errorBelch ("getNumberOfSymbols: error whilst reading `%s' "
                              "image header in `%" PATH_FMT "'",
                              member_name, arch_name);
                  return NULL;
                }
                fseek (f, -(long int)sizeof(IMAGE_FILE_HEADER), SEEK_CUR);
                if (!verifyCOFFHeader (hdr.Machine, &hdr, arch_name)) {
                    return NULL;
                }
                numberOfSymbols = hdr.NumberOfSymbols;
            }
            break;
           case COFF_ANON_BIG_OBJ:
            {
                ANON_OBJECT_HEADER_BIGOBJ hdr;
                n = fread (&hdr, 1, sizeof(ANON_OBJECT_HEADER_BIGOBJ), f);
                if (n != sizeof(ANON_OBJECT_HEADER_BIGOBJ))
                {
                  errorBelch ("getNumberOfSymbols: error whilst reading `%s' "
                              "big obj header in `%" PATH_FMT "'",
                              member_name, arch_name);
                  return NULL;
                }
                fseek (f, -(long int)sizeof(ANON_OBJECT_HEADER_BIGOBJ), SEEK_CUR);
                if (!verifyCOFFHeader (hdr.Machine, NULL, arch_name)) {
                    return NULL;
                }
                numberOfSymbols = hdr.NumberOfSymbols;
            }
            break;
           case COFF_ANON_OBJ:
             barf ("COFF_ANON_OBJ should not be allocated with "
                   "allocateImageAndTrampolines. It is not specific enough.\n");
           case COFF_IMPORT_LIB:
             barf ("COFF_IMPORT_LIB should not be allocated with "
                   "allocateImageAndTrampolines. It is read-only.\n");
           case COFF_UNKNOWN:
           default:
            {
              errorBelch (
                  "getNumberOfSymbols: error whilst reading `%s' header "
                  "in `%" PATH_FMT "': Unknown COFF_OBJ_TYPE.",
                  member_name, arch_name);
              return NULL;
            }
       }

       /* We get back 8-byte aligned memory (is that guaranteed?), but
          the offsets to the sections within the file are all 4 mod 8
          (is that guaranteed?). We therefore need to offset the image
          by 4, so that all the pointers are 8-byte aligned, so that
          pointer tagging works. */
       /* For 32-bit case we don't need this, hence we use macro PEi386_IMAGE_OFFSET,
          which equals to 4 for 64-bit case and 0 for 32-bit case. */
       /* We allocate trampolines area for all symbols right behind
          image data, aligned on 8. */
       size = ((PEi386_IMAGE_OFFSET + size + 0x7) & ~0x7)
           + numberOfSymbols * sizeof(SymbolExtra);
   }
#endif
   image = VirtualAlloc(NULL, size,
                        MEM_RESERVE | MEM_COMMIT,
                        PAGE_EXECUTE_READWRITE);

   if (image == NULL) {
       errorBelch("%" PATH_FMT ": failed to allocate memory for image for %s",
                  arch_name, member_name);
       return NULL;
   }

   return image + PEi386_IMAGE_OFFSET;
}

/* -----------------------
 * This loads import libraries following Microsoft's official standard in the PE
 * documentation. This is a smaller more efficient format which is just a list
 * of symbol name => dll.
 *
 * This function must fail gracefully and if it does, the filestream needs to
 * be reset to what it was when the function was called.
 */
bool checkAndLoadImportLibrary( pathchar* arch_name, char* member_name, FILE* f )
{
    char* image;
    static bool load_dll_warn = false;

    if (load_dll_warn) { return 0; }

    /* Based on Import Library specification. PE Spec section 7.1 */

    COFF_import_header hdr;
    size_t n;

    n = fread(&hdr, 1, sizeof_COFF_import_Header, f);
    if (n != sizeof_COFF_import_Header)  {
        errorBelch("loadImportLibrary: error whilst reading `%s' header "
                   "in `%" PATH_FMT "'\n",
                   member_name, arch_name);
        fseek(f, -(long int)sizeof_COFF_import_Header, SEEK_CUR);
        return false;
    }

    if (   hdr.Sig1 != IMAGE_FILE_MACHINE_UNKNOWN
        || hdr.Sig2 != IMPORT_OBJECT_HDR_SIG2
        || getObjectType ((char*)&hdr, arch_name) != COFF_IMPORT_LIB) {
        fseek(f, -(long int)sizeof_COFF_import_Header, SEEK_CUR);
        IF_DEBUG(linker, debugBelch("loadArchive: Object `%s` is not an import lib. Skipping...\n", member_name));
        return false;
    }

    IF_DEBUG(linker, debugBelch("loadArchive: reading %lu bytes at %ld\n", hdr.SizeOfData, ftell(f)));

    image = malloc(hdr.SizeOfData);
    n = fread(image, 1, hdr.SizeOfData, f);
    if (n != hdr.SizeOfData) {
        errorBelch("loadArchive: error whilst reading `%s' header in `%" PATH_FMT "'. Did not read enough bytes.\n",
            member_name, arch_name);
        fseek(f, -(n + sizeof_COFF_import_Header), SEEK_CUR);
        return false;
    }

    char* symbol  = strtok(image, "\0");
    int symLen    = strlen(symbol) + 1;
    int nameLen   = n - symLen;
    char* dllName = malloc(sizeof(char) * nameLen);
    dllName       = strncpy(dllName, image + symLen, nameLen);
    pathchar* dll = malloc(sizeof(wchar_t) * nameLen);
    mbstowcs(dll, dllName, nameLen);
    free(dllName);

    IF_DEBUG(linker, debugBelch("loadArchive: read symbol %s from lib `%" PATH_FMT "'\n", symbol, dll));
    const char* result = addDLL(dll);

    free(image);

    if (result != NULL) {
        errorBelch("Could not load `%" PATH_FMT "'. Reason: %s\n", dll, result);
        load_dll_warn = true;

        free(dll);
        fseek(f, -(n + sizeof_COFF_import_Header), SEEK_CUR);
        return false;
    }

    free(dll);
    return true;
}

static void
printName ( uint8_t* name, uint8_t* strtab )
{
   if (name[0]==0 && name[1]==0 && name[2]==0 && name[3]==0) {
      uint32_t strtab_offset = * (uint32_t*)(name+4);
      debugBelch("%s", strtab + strtab_offset );
   } else {
      int i;
      for (i = 0; i < 8; i++) {
         if (name[i] == 0) break;
         debugBelch("%c", name[i] );
      }
   }
}


static void
copyName ( uint8_t* name, uint8_t* strtab, uint8_t* dst, int dstSize )
{
   if (name[0]==0 && name[1]==0 && name[2]==0 && name[3]==0) {
      uint32_t strtab_offset = * (uint32_t*)(name+4);
      strncpy ( (char*)dst, (char*)strtab+strtab_offset, dstSize );
      dst[dstSize-1] = 0;
   } else {
      int i = 0;
      while (1) {
         if (i >= 8) break;
         if (name[i] == 0) break;
         dst[i] = name[i];
         i++;
      }
      dst[i] = 0;
   }
}


static uint8_t *
cstring_from_COFF_symbol_name ( uint8_t* name, uint8_t* strtab )
{
   uint8_t* newstr;
   /* If the string is longer than 8 bytes, look in the
      string table for it -- this will be correctly zero terminated.
   */
   if (name[0]==0 && name[1]==0 && name[2]==0 && name[3]==0) {
      uint32_t strtab_offset = * (uint32_t*)(name+4);
      return strtab + strtab_offset;
   }
   /* Otherwise, if shorter than 8 bytes, return the original,
      which by defn is correctly terminated.
   */
   if (name[7]==0) return name;
   /* The annoying case: 8 bytes.  Copy into a temporary
      (XXX which is never freed ...)
   */
   newstr = stgMallocBytes(9, "cstring_from_COFF_symbol_name");
   ASSERT(newstr);
   strncpy((char*)newstr,(char*)name,8);
   newstr[8] = 0;
   return newstr;
}

/* Getting the name of a section is mildly tricky, so we make a
   function for it.  Sadly, in one case we have to copy the string
   (when it is exactly 8 bytes long there's no trailing '\0'), so for
   consistency we *always* copy the string; the caller must free it
*/
char *
cstring_from_section_name (uint8_t* name, uint8_t* strtab)
{
    char *newstr;

    if (name[0]=='/') {
        int strtab_offset = strtol((char*)name+1,NULL,10);
        int len = strlen(((char*)strtab) + strtab_offset);

        newstr = stgMallocBytes(len+1, "cstring_from_section_symbol_name");
        strcpy(newstr, (char*)strtab + strtab_offset);
        return newstr;
    }
    else
    {
        newstr = stgMallocBytes(9, "cstring_from_section_symbol_name");
        ASSERT(newstr);
        strncpy(newstr,(char*)name,8);
        newstr[8] = 0;
        return newstr;
    }
}

/* See Note [mingw-w64 name decoration scheme] */
#if !defined(x86_64_HOST_ARCH)
static void
zapTrailingAtSign ( uint8_t* sym )
{
#  define my_isdigit(c) ((c) >= '0' && (c) <= '9')
   int i, j;
   if (sym[0] == 0) return;
   i = 0;
   while (sym[i] != 0) i++;
   i--;
   j = i;
   while (j > 0 && my_isdigit(sym[j])) j--;
   if (j > 0 && sym[j] == '@' && j != i) sym[j] = 0;
#  undef my_isdigit
}
#endif

SymbolAddr*
lookupSymbolInDLLs ( uint8_t *lbl )
{
    OpenedDLL* o_dll;
    SymbolAddr* sym;

    for (o_dll = opened_dlls; o_dll != NULL; o_dll = o_dll->next) {
        /* debugBelch("look in %ls for %s\n", o_dll->name, lbl); */

        sym = GetProcAddress(o_dll->instance, (char*)(lbl+STRIP_LEADING_UNDERSCORE));
        if (sym != NULL) {
            /*debugBelch("found %s in %s\n", lbl+1,o_dll->name);*/
            return sym;
        }

        /* Ticket #2283.
           Long description: http://support.microsoft.com/kb/132044
           tl;dr:
             If C/C++ compiler sees __declspec(dllimport) ... foo ...
             it generates call *__imp_foo, and __imp_foo here has exactly
             the same semantics as in __imp_foo = GetProcAddress(..., "foo")
         */
        if (sym == NULL && strncmp ((const char*)lbl, "__imp_", 6) == 0) {
            sym = GetProcAddress(o_dll->instance, (char*)(lbl+6+STRIP_LEADING_UNDERSCORE));
            if (sym != NULL) {
                IndirectAddr* ret;
                ret = stgMallocBytes( sizeof(IndirectAddr), "lookupSymbolInDLLs" );
                ret->addr = sym;
                ret->next = indirects;
                indirects = ret;
                IF_DEBUG(linker,
                  debugBelch("warning: %s from %S is linked instead of %s\n",
                             (char*)(lbl+6+STRIP_LEADING_UNDERSCORE), o_dll->name, (char*)lbl));
                return (void*) & ret->addr;
               }
        }

        sym = GetProcAddress(o_dll->instance, (char*)lbl);
        if (sym != NULL) {
            /*debugBelch("found %s in %s\n", lbl,o_dll->name);*/
            return sym;
           }
    }
    return NULL;
}

static bool
verifyCOFFHeader ( uint16_t machine, IMAGE_FILE_HEADER *hdr,
                   pathchar *fileName )
{
#if defined(i386_HOST_ARCH)
   if (machine != IMAGE_FILE_MACHINE_I386) {
      errorBelch("%" PATH_FMT ": Not a x86 PE file.", fileName);
      return false;
   }
#elif defined(x86_64_HOST_ARCH)
   if (machine != IMAGE_FILE_MACHINE_AMD64) {
      errorBelch("%" PATH_FMT ": Not a x86_64 PE+ file.", fileName);
      return false;
   }
#else
   errorBelch("PE/PE+ not supported on this arch.");
#endif

   if (!hdr)
     return true;

   if (hdr->SizeOfOptionalHeader != 0) {
      errorBelch("%" PATH_FMT ": PE/PE+ with nonempty optional header",
                 fileName);
      return 0;
   }
   if ( (hdr->Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE) ||
        (hdr->Characteristics & IMAGE_FILE_DLL             ) ||
        (hdr->Characteristics & IMAGE_FILE_SYSTEM          ) ) {
      errorBelch("%" PATH_FMT ": Not a PE/PE+ object file", fileName);
      return false;
   }
   if ( (hdr->Characteristics & IMAGE_FILE_BYTES_REVERSED_HI)) {
      errorBelch("%" PATH_FMT ": Invalid PE/PE+ word size or endiannness: %d",
                 fileName,
                 (int)(hdr->Characteristics));
      return false;
   }
   return true;
}

bool
ocVerifyImage_PEi386 ( ObjectCode* oc )
{
   unsigned int i;
   uint32_t j, noRelocs;
   COFF_section* sectab;
   COFF_symbol*  symtab;
   uint8_t*      strtab;

   COFF_HEADER_INFO *info = getHeaderInfo (oc);

   sectab = (COFF_section*) (
               ((uint8_t*)(oc->image))
               + info->sizeOfHeader + info->sizeOfOptionalHeader
            );
   symtab = (COFF_symbol*) (
               ((uint8_t*)(oc->image))
               + info->pointerToSymbolTable
            );
   strtab = ((uint8_t*)symtab)
            + info->numberOfSymbols * getSymbolSize (info);

   /* If the string table size is way crazy, this might indicate that
      there are more than 64k relocations, despite claims to the
      contrary.  Hence this test. */
   /* debugBelch("strtab size %d\n", * (uint32_t*)strtab); */
#if 0
   if ( (*(uint32_t*)strtab) > 600000 ) {
      /* Note that 600k has no special significance other than being
         big enough to handle the almost-2MB-sized lumps that
         constitute HSwin32*.o. */
      debugBelch("PEi386 object has suspiciously large string table; > 64k relocs?");
      return false;
   }
#endif

   /* .BSS Section is initialized in ocGetNames_PEi386
      but we need the Sections array initialized here already. */
   Section *sections;
   sections = (Section*)stgCallocBytes(
       sizeof(Section),
       info->numberOfSections + 1, /* +1 for the global BSS section see ocGetNames_PEi386 */
       "ocVerifyImage_PEi386(sections)");
   oc->sections = sections;
   oc->n_sections = info->numberOfSections + 1;

   /* Initialize the Sections */
   for (i = 0; i < info->numberOfSections; i++) {
       COFF_section* sectab_i
           = (COFF_section*)
           myindex(sizeof_COFF_section, sectab, i);

       /* Calculate the start of the data section */
       sections[i].start = oc->image + sectab_i->PointerToRawData;
   }

   /* No further verification after this point; only debug printing. */
   i = 0;
   IF_DEBUG(linker, i=1);
   if (i == 0)
    {
      stgFree (info);
      return true;
    }

   debugBelch("sectab offset = %" FMT_SizeT "\n",
              ((uint8_t*)sectab) - ((uint8_t*)oc->image) );
   debugBelch("symtab offset = %" FMT_SizeT "\n",
              ((uint8_t*)symtab) - ((uint8_t*)oc->image) );
   debugBelch("strtab offset = %" FMT_SizeT "\n",
              ((uint8_t*)strtab) - ((uint8_t*)oc->image) );

   debugBelch("\n" );
   if (info->type == COFF_IMAGE)
    {
      IMAGE_FILE_HEADER* hdr = (IMAGE_FILE_HEADER*)oc->image;
      debugBelch( "COFF Type:         IMAGE_FILE_HEADER\n");
      debugBelch( "Machine:           0x%x\n",
                  (uint32_t)(hdr->Machine) );
      debugBelch( "# sections:        %d\n",
                  (uint32_t)(hdr->NumberOfSections) );
      debugBelch( "time/date:         0x%x\n",
                  (uint32_t)(hdr->TimeDateStamp) );
      debugBelch( "symtab offset:     %d\n",
                  (uint32_t)(hdr->PointerToSymbolTable) );
      debugBelch( "# symbols:         %d\n",
                  (uint32_t)(hdr->NumberOfSymbols) );
      debugBelch( "sz of opt hdr:     %d\n",
                  (uint32_t)(hdr->SizeOfOptionalHeader) );
      debugBelch( "characteristics:   0x%x\n",
                  (uint32_t)(hdr->Characteristics) );
    }
   else if (info->type == COFF_ANON_BIG_OBJ)
    {
      ANON_OBJECT_HEADER_BIGOBJ* hdr = (ANON_OBJECT_HEADER_BIGOBJ*)oc->image;
      debugBelch( "COFF Type:         ANON_OBJECT_HEADER_BIGOBJ\n");
      debugBelch( "Machine:           0x%x\n",
                  (uint32_t)(hdr->Machine) );
      debugBelch( "# sections:        %d\n",
                  (uint32_t)(hdr->NumberOfSections) );
      debugBelch( "time/date:         0x%x\n",
                  (uint32_t)(hdr->TimeDateStamp) );
      debugBelch( "symtab offset:     %d\n",
                  (uint32_t)(hdr->PointerToSymbolTable) );
      debugBelch( "# symbols:         %d\n",
                  (uint32_t)(hdr->NumberOfSymbols) );
    }
   else
    {
      debugBelch( "COFF Type:         UNKNOWN\n");
      stgFree (info);
      return false;
    }

   /* Print the section table. */
   debugBelch("\n" );
   for (i = 0; i < info->numberOfSections; i++) {
      COFF_reloc* reltab;
      COFF_section* sectab_i
         = (COFF_section*)
           myindex ( sizeof_COFF_section, sectab, i );
      Section section = sections[i];
      debugBelch(
                "\n"
                "section %d\n"
                "     name `",
                i
              );
      printName ( sectab_i->Name, strtab );
      debugBelch(
                "'\n"
                "    vsize %lu\n"
                "    vaddr %lu\n"
                "  data sz %lu\n"
                " data off 0x%p\n"
                "  num rel %hu\n"
                "  off rel %lu\n"
                "  ptr raw 0x%lx\n",
                sectab_i->Misc.VirtualSize,
                sectab_i->VirtualAddress,
                sectab_i->SizeOfRawData,
                section.start,
                sectab_i->NumberOfRelocations,
                sectab_i->PointerToRelocations,
                sectab_i->PointerToRawData
              );
      reltab = (COFF_reloc*) (
                  ((uint8_t*)(oc->image)) + sectab_i->PointerToRelocations
               );

      if ( sectab_i->Characteristics & IMAGE_SCN_LNK_NRELOC_OVFL ) {
        /* If the relocation field (a short) has overflowed, the
         * real count can be found in the first reloc entry.
         *
         * See Section 4.1 (last para) of the PE spec (rev6.0).
         */
        COFF_reloc* rel = (COFF_reloc*)
                           myindex ( sizeof_COFF_reloc, reltab, 0 );
        noRelocs = rel->VirtualAddress;
        j = 1;
      } else {
        noRelocs = sectab_i->NumberOfRelocations;
        j = 0;
      }

      for (; j < noRelocs; j++) {
         COFF_symbol* sym;
         COFF_reloc* rel = (COFF_reloc*)
                           myindex ( sizeof_COFF_reloc, reltab, j );
         debugBelch(
                   "        type 0x%-4x   vaddr 0x%-8lx   name `",
                   (uint32_t)rel->Type,
                   rel->VirtualAddress );
         sym = (COFF_symbol*)
               myindex ( getSymbolSize (info), symtab, rel->SymbolTableIndex );
         printName ( getSymShortName (info, sym), strtab );
         debugBelch("'\n" );
      }

      debugBelch("\n" );
   }
   debugBelch("\n" );
   debugBelch("string table has size 0x%x\n", * (uint32_t*)strtab );
   debugBelch("---START of string table---\n");
   for (i = 4; i < *(uint32_t*)strtab; i++) {
      if (strtab[i] == 0)
         debugBelch("\n"); else
         debugBelch("%c", strtab[i] );
   }
   debugBelch("--- END  of string table---\n");

   debugBelch("\n" );
   i = 0;
   while (1) {
      COFF_symbol* symtab_i;
      if (i >= info->numberOfSymbols) break;
      symtab_i = (COFF_symbol*)
                 myindex ( getSymbolSize (info), symtab, i );
      debugBelch(
                "symbol %d\n"
                "     name `",
                i
              );
      printName ( getSymShortName (info, symtab_i), strtab );
      debugBelch(
                "'\n"
                "    value 0x%x\n"
                "   1+sec# %d\n"
                "     type 0x%x\n"
                "   sclass 0x%x\n"
                "     nAux %d\n",
                getSymValue (info, symtab_i),
                getSymSectionNumber (info, symtab_i),
                getSymType (info, symtab_i),
                getSymStorageClass (info, symtab_i),
                getSymNumberOfAuxSymbols (info, symtab_i)
              );
      i += getSymNumberOfAuxSymbols (info, symtab_i);
      i++;
   }

   debugBelch("\n" );
   stgFree (info);
   return true;
}

bool
ocGetNames_PEi386 ( ObjectCode* oc )
{
   COFF_section* sectab;
   COFF_symbol*  symtab;
   uint8_t*        strtab;
   bool          has_code_section = false;

   uint8_t*     sname;
   SymbolAddr* addr;
   unsigned int   i;

   COFF_HEADER_INFO *info = getHeaderInfo (oc);

   sectab = (COFF_section*) (
               ((uint8_t*)(oc->image))
               + info->sizeOfHeader + info->sizeOfOptionalHeader
            );
   symtab = (COFF_symbol*) (
               ((uint8_t*)(oc->image))
               + info->pointerToSymbolTable
            );
   strtab = ((uint8_t*)(oc->image))
            + info->pointerToSymbolTable
            + info->numberOfSymbols * getSymbolSize (info);

   /* Allocate space for any (local, anonymous) .bss sections. */

   for (i = 0; i < info->numberOfSections; i++) {
      uint32_t bss_sz;
      uint8_t* zspace;
      COFF_section* sectab_i
         = (COFF_section*)
           myindex ( sizeof_COFF_section, sectab, i );

      char *secname = cstring_from_section_name(sectab_i->Name, strtab);

      if (0 != strcmp(secname, ".bss")) {
          stgFree(secname);
          continue;
      }

      stgFree(secname);

      /* sof 10/05: the PE spec text isn't too clear regarding what
       * the SizeOfRawData field is supposed to hold for object
       * file sections containing just uninitialized data -- for executables,
       * it is supposed to be zero; unclear what it's supposed to be
       * for object files. However, VirtualSize is guaranteed to be
       * zero for object files, which definitely suggests that SizeOfRawData
       * will be non-zero (where else would the size of this .bss section be
       * stored?) Looking at the COFF_section info for incoming object files,
       * this certainly appears to be the case.
       *
       * => I suspect we've been incorrectly handling .bss sections in (relocatable)
       * object files up until now. This turned out to bite us with ghc-6.4.1's use
       * of gcc-3.4.x, which has started to emit initially-zeroed-out local 'static'
       * variable decls into the .bss section. (The specific function in Q which
       * triggered this is libraries/base/cbits/dirUtils.c:__hscore_getFolderPath())
       */
      if (sectab_i->Misc.VirtualSize == 0 && sectab_i->SizeOfRawData == 0) continue;
      /* This is a non-empty .bss section.
         Allocate zeroed space for it */
      bss_sz = sectab_i->Misc.VirtualSize;
      if ( bss_sz < sectab_i->SizeOfRawData) { bss_sz = sectab_i->SizeOfRawData; }
      zspace = stgCallocBytes(1, bss_sz, "ocGetNames_PEi386(anonymous bss)");
      oc->sections[i].start = zspace;
      addProddableBlock(oc, zspace, bss_sz);
      /* debugBelch("BSS anon section at 0x%x\n", zspace); */
   }

   /* Copy section information into the ObjectCode. */

   for (i = 0; i < info->numberOfSections; i++) {
      uint8_t* start;
      uint8_t* end;
      uint32_t sz;

      /* By default consider all section as CODE or DATA, which means we want to load them. */
      SectionKind kind
          = SECTIONKIND_CODE_OR_RODATA;
      COFF_section* sectab_i
         = (COFF_section*)
           myindex ( sizeof_COFF_section, sectab, i );
      Section section = oc->sections[i];

      char *secname = cstring_from_section_name(sectab_i->Name, strtab);

      IF_DEBUG(linker, debugBelch("section name = %s\n", secname ));

      /* The PE file section flag indicates whether the section contains code or data. */
      if (sectab_i->Characteristics & IMAGE_SCN_CNT_CODE) {
          has_code_section = has_code_section || sectab_i->SizeOfRawData > 0;
          kind = SECTIONKIND_CODE_OR_RODATA;
       }

       if (sectab_i->Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA)
           kind = SECTIONKIND_CODE_OR_RODATA;

      /* Check next if it contains any uninitialized data */
      if (sectab_i->Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA)
          kind = SECTIONKIND_RWDATA;

      /* Finally check if it can be discarded. This will also ignore .debug sections */
      if (sectab_i->Characteristics & IMAGE_SCN_MEM_DISCARDABLE ||
          sectab_i->Characteristics & IMAGE_SCN_LNK_REMOVE)
          kind = SECTIONKIND_OTHER;

      if (0==strncmp(".ctors", (char*)secname, 6))
          kind = SECTIONKIND_INIT_ARRAY;

      if (0==strncmp(".idata", (char*)secname, 6))
          kind = SECTIONKIND_IMPORT;

      /* See Note [BFD import library].  */
      if (0==strncmp(".idata$7", (char*)secname, 8))
          kind = SECTIONKIND_IMPORT_LIBRARY;

      if (0==strncmp(".idata$6", (char*)secname, 8)) {
          /* The first two bytes contain the ordinal of the function
             in the format of lowpart highpart. The two bytes combined
             for the total range of 16 bits which is the function export limit
             of DLLs.  */
          sname = ((uint8_t*)section.start)+2;
          COFF_symbol* symtab_i = (COFF_symbol*)
                myindex ( getSymbolSize(info), symtab, info->numberOfSymbols-1 );
          addr = (char*)cstring_from_COFF_symbol_name(
                               getSymShortName (info, symtab_i),
                               strtab);
          stgFree (info);

          IF_DEBUG(linker,
                   debugBelch("addImportSymbol `%s' => `%s'\n",
                              sname, (char*)addr));
          if (!ghciInsertSymbolTable(oc->fileName, symhash, (SymbolName*)sname,
                                     addr, false, oc))
             return false;
          setImportSymbol (oc, sname);

          /* Don't process this oc any futher. Just exit.  */
          oc->n_symbols = 0;
          oc->symbols   = NULL;
          return true;
      }

      ASSERT(sectab_i->SizeOfRawData == 0 || sectab_i->Misc.VirtualSize == 0);
      sz = sectab_i->SizeOfRawData;
      if (sz < sectab_i->Misc.VirtualSize) sz = sectab_i->Misc.VirtualSize;

      start = section.start;
      end   = start + sz - 1;

      if (kind != SECTIONKIND_OTHER && end >= start) {
          addSection(&oc->sections[i], kind, SECTION_NOMEM, start, sz, 0, 0, 0);
          addProddableBlock(oc, start, sz);
      }

      stgFree(secname);
   }

   /* Copy exported symbols into the ObjectCode. */

   oc->n_symbols = info->numberOfSymbols;
   oc->symbols   = stgCallocBytes(sizeof(SymbolName*), oc->n_symbols,
                                  "ocGetNames_PEi386(oc->symbols)");

   /* Work out the size of the global BSS section */
   StgWord globalBssSize = 0;
   for (i=0; i < info->numberOfSymbols; i++) {
      COFF_symbol* symtab_i;
       symtab_i = (COFF_symbol*)
           myindex ( getSymbolSize (info), symtab, i );
       if (getSymSectionNumber (info, symtab_i) == IMAGE_SYM_UNDEFINED
           && getSymValue (info, symtab_i) > 0
           && getSymStorageClass (info, symtab_i) != IMAGE_SYM_CLASS_SECTION) {
           globalBssSize += getSymValue (info, symtab_i);
       }
       i += getSymNumberOfAuxSymbols (info, symtab_i);
   }

   /* Allocate BSS space */
   SymbolAddr* bss = NULL;
   if (globalBssSize > 0) {
       bss = stgCallocBytes(1, globalBssSize,
                            "ocGetNames_PEi386(non-anonymous bss)");
       addSection(&oc->sections[oc->n_sections-1],
                  SECTIONKIND_RWDATA, SECTION_MALLOC,
                  bss, globalBssSize, 0, 0, 0);
       IF_DEBUG(linker, debugBelch("bss @ %p %" FMT_Word "\n", bss, globalBssSize));
       addProddableBlock(oc, bss, globalBssSize);
   } else {
       addSection(&oc->sections[oc->n_sections-1],
                  SECTIONKIND_OTHER, SECTION_NOMEM, NULL, 0, 0, 0, 0);
   }

   for (i = 0; i < (uint32_t)oc->n_symbols; i++) {
      COFF_symbol* symtab_i;
      symtab_i = (COFF_symbol*)
                 myindex ( getSymbolSize (info), symtab, i );

      int32_t secNumber = getSymSectionNumber (info, symtab_i);
      uint32_t symValue = getSymValue (info, symtab_i);
      uint8_t symStorageClass = getSymStorageClass (info, symtab_i);

      addr = NULL;
      bool isWeak = false;
      Section *section = secNumber > 0
                       ? &oc->sections[secNumber-1]
                       : NULL;
      sname = cstring_from_COFF_symbol_name(getSymShortName (info, symtab_i), strtab);

      if (   secNumber != IMAGE_SYM_UNDEFINED
          && secNumber > 0
          && section
          && section->kind != SECTIONKIND_IMPORT_LIBRARY) {
         /* This symbol is global and defined, viz, exported */
         /* for IMAGE_SYMCLASS_EXTERNAL
                && !IMAGE_SYM_UNDEFINED,
            the address of the symbol is:
                address of relevant section + offset in section
         */
         COFF_section* sectabent
            = (COFF_section*) myindex ( sizeof_COFF_section,
                                        sectab, secNumber-1 );
         if (symStorageClass == IMAGE_SYM_CLASS_EXTERNAL
            || (   symStorageClass == IMAGE_SYM_CLASS_STATIC
                && sectabent->Characteristics & IMAGE_SCN_LNK_COMDAT
                && section)
            ) {
                 addr = (void*)((size_t)section->start
                      + symValue);
                 if (sectabent->Characteristics & IMAGE_SCN_LNK_COMDAT) {
                    isWeak = true;
              }
         }
      }
      else if (symStorageClass == IMAGE_SYM_CLASS_WEAK_EXTERNAL) {
          isWeak = true;
      }
      else if (  secNumber == IMAGE_SYM_UNDEFINED && symValue > 0) {
         /* This symbol isn't in any section at all, ie, global bss.
            Allocate zeroed space for it from the BSS section */
          addr = bss;
          bss = (SymbolAddr*)((StgWord)bss + (StgWord)symValue);
          IF_DEBUG(linker, debugBelch("bss symbol @ %p %u\n", addr, symValue));
      }
      else if (secNumber > 0
               && section
               && section->kind == SECTIONKIND_IMPORT_LIBRARY) {
          /* This is an import section. We should load the dll and lookup
             the symbols.
             See Note [BFD import library].  */
          char* dllName = (char*)section->start;
          if (strlen(dllName) == 0 || dllName[0] == 0 || has_code_section)
              continue;

          pathchar* dirName = pathdir(oc->fileName);
          HsPtr token       = addLibrarySearchPath(dirName);
          stgFree(dirName);

          symtab_i = (COFF_symbol*)
                 myindex ( getSymbolSize (info), symtab, oc->n_symbols-1 );
          sname = cstring_from_COFF_symbol_name(getSymShortName (info, symtab_i), strtab);

          IF_DEBUG(linker,
                   debugBelch("loading symbol `%s' from dll: '%ls' => `%s'\n",
                              sname, oc->fileName, dllName));

          pathchar* dll = mkPath(dllName);
          HINSTANCE dllInstance = 0;
          const char* result = addDLL_PEi386(dll, &dllInstance);
          removeLibrarySearchPath(token);
          stgFree(dll);

          if (result != NULL || dllInstance == 0) {
              errorBelch("Could not load `%s'. Reason: %s\n",
                         (char*)dllName, result);
              stgFree (info);
              return false;
          }

          /* Set the _dll_iname symbol to the dll's handle.  */
          addr = (SymbolAddr*)dllInstance;

          /* the symbols are named <name>_iname when defined, but are named
             _head_<name> when looked up. (Ugh. thanks GCC.) So correct it when
             stored so we don't have to correct it each time when retrieved.  */
          int size = strlen((char*)sname)+1;
          char *tmp = stgMallocBytes(size*sizeof(char),
                                     "ocGetNames_PEi386");
          strncpy(tmp, (char*)sname, size);
          char *pos = strstr(tmp, "_iname");
          /* drop anything after the name. There are some inconsistencies with
             whitespaces trailing the name.  */
          if (pos) pos[0] = '\0';
          int start = 0;

          /* msys2 project's import lib builder has some inconsistent name
             manglings. Their names start with _ or __ yet they drop this when
             making the _head_ symbol. So do the same.  */
          while (tmp[start]=='_')
            start++;

          snprintf((char*)sname, size, "_head_%s", tmp+start);
          sname[size-start]='\0';
          stgFree(tmp);
          if (!ghciInsertSymbolTable(oc->fileName, symhash, (SymbolName*)sname,
                                     addr, false, oc)) {
               stgFree (info);
               return false;
          }
          break;
      }

      if ((addr != NULL || isWeak)
         && (!section || (section && section->kind != SECTIONKIND_IMPORT))) {
         /* debugBelch("addSymbol %p `%s' Weak:%lld \n", addr, sname, isWeak); */
         IF_DEBUG(linker, debugBelch("addSymbol %p `%s'\n", addr,sname));
         ASSERT(i < (uint32_t)oc->n_symbols);
         /* cstring_from_COFF_symbol_name always succeeds. */
         oc->symbols[i] = (SymbolName*)sname;
         if (isWeak) {
             setWeakSymbol(oc, sname);
         }

         if (! ghciInsertSymbolTable(oc->fileName, symhash, (SymbolName*)sname, addr,
                                     isWeak, oc)) {
             stgFree (info);
             return false;
         }
      } else {
          /* We're skipping the symbol, but if we ever load this
          object file we'll want to skip it then too. */
          oc->symbols[i] = NULL;

#        if 0
         debugBelch(
                   "IGNORING symbol %d\n"
                   "     name `",
                   i
                 );
         printName ( getSymShortName (info, symtab_i), strtab );
         debugBelch(
                   "'\n"
                   "    value 0x%x\n"
                   "   1+sec# %d\n"
                   "     type 0x%x\n"
                   "   sclass 0x%x\n"
                   "     nAux %d\n",
                   symValue,
                   getSymSectionNumber (info, symtab_i),
                   getSymType (info, symtab_i),
                   getSymStorageClass (info, symtab_i),
                   getSymNumberOfAuxSymbols (info, symtab_i)
                 );
#        endif
      }

      i += getSymNumberOfAuxSymbols (info, symtab_i);
   }

   stgFree (info);
   return true;
}

#if defined(x86_64_HOST_ARCH)

/* We've already reserved a room for symbol extras in loadObj,
 * so simply set correct pointer here.
 */
bool
ocAllocateSymbolExtras_PEi386 ( ObjectCode* oc )
{
   oc->symbol_extras = (SymbolExtra*)(oc->image - PEi386_IMAGE_OFFSET
                                      + ((PEi386_IMAGE_OFFSET + oc->fileSize + 0x7) & ~0x7));
   oc->first_symbol_extra = 0;
   COFF_HEADER_INFO *info = getHeaderInfo (oc);
   oc->n_symbol_extras = info->numberOfSymbols;
   stgFree (info);

   return true;
}

static size_t
makeSymbolExtra_PEi386( ObjectCode* oc, uint64_t index, size_t s, char* symbol )
{
    unsigned int curr_thunk;
    SymbolExtra *extra;
    curr_thunk = oc->first_symbol_extra + index;
    if (index >= oc->n_symbol_extras) {
      IF_DEBUG(linker, debugBelch("makeSymbolExtra first:%d, num:%lu, member:%s, index:%llu\n", curr_thunk, oc->n_symbol_extras, oc->archiveMemberName, index));
      barf("Can't allocate thunk for `%s' in `%" PATH_FMT "' with member `%s'", symbol, oc->fileName, oc->archiveMemberName);
    }

    extra = oc->symbol_extras + curr_thunk;

    if (!extra->addr)
    {
        // jmp *-14(%rip)
        static uint8_t jmp[] = { 0xFF, 0x25, 0xF2, 0xFF, 0xFF, 0xFF };
        extra->addr = (uint64_t)s;
        memcpy(extra->jumpIsland, jmp, 6);
    }

    return (size_t)extra->jumpIsland;
}

#endif /* x86_64_HOST_ARCH */

bool
ocResolve_PEi386 ( ObjectCode* oc )
{
   COFF_section* sectab;
   COFF_symbol*  symtab;
   uint8_t*      strtab;

   uint32_t    A;
   size_t      S;
   SymbolAddr* pP;

   unsigned int i;
   uint32_t j, noRelocs;

   /* ToDo: should be variable-sized?  But is at least safe in the
      sense of buffer-overrun-proof. */
   uint8_t symbol[1000];
   /* debugBelch("resolving for %s\n", oc->fileName); */

   COFF_HEADER_INFO *info = getHeaderInfo (oc);

   sectab = (COFF_section*) (
               ((uint8_t*)(oc->image))
               + info->sizeOfHeader + info->sizeOfOptionalHeader
            );
   symtab = (COFF_symbol*) (
               ((uint8_t*)(oc->image))
               + info->pointerToSymbolTable
            );
   strtab = ((uint8_t*)(oc->image))
            + info->pointerToSymbolTable
            + info->numberOfSymbols * getSymbolSize (info);

   uint32_t numberOfSections = info->numberOfSections;

   for (i = 0; i < numberOfSections; i++) {
      COFF_section* sectab_i
         = (COFF_section*)
           myindex ( sizeof_COFF_section, sectab, i );
      COFF_reloc* reltab
         = (COFF_reloc*) (
              ((uint8_t*)(oc->image)) + sectab_i->PointerToRelocations
           );
      Section section = oc->sections[i];

      char *secname = cstring_from_section_name(sectab_i->Name, strtab);

      /* Ignore sections called which contain stabs debugging information. */
      if (    0 == strcmp(".stab", (char*)secname)
           || 0 == strcmp(".stabstr", (char*)secname)
           || 0 == strncmp(".pdata", (char*)secname, 6)
           || 0 == strncmp(".xdata", (char*)secname, 6)
           || 0 == strncmp(".debug", (char*)secname, 6)
           || 0 == strcmp(".rdata$zzz", (char*)secname)) {
           stgFree(secname);
           continue;
      }

      stgFree(secname);

      if ( sectab_i->Characteristics & IMAGE_SCN_LNK_NRELOC_OVFL ) {
        /* If the relocation field (a short) has overflowed, the
         * real count can be found in the first reloc entry.
         *
         * See Section 4.1 (last para) of the PE spec (rev6.0).
         *
         * Nov2003 update: the GNU linker still doesn't correctly
         * handle the generation of relocatable object files with
         * overflown relocations. Hence the output to warn of potential
         * troubles.
         */
        COFF_reloc* rel = (COFF_reloc*)
                           myindex ( sizeof_COFF_reloc, reltab, 0 );
        noRelocs = rel->VirtualAddress;

        /* 10/05: we now assume (and check for) a GNU ld that is capable
         * of handling object files with (>2^16) of relocs.
         */
#if 0
        debugBelch("WARNING: Overflown relocation field (# relocs found: %u)\n",
                   noRelocs);
#endif
        j = 1;
      } else {
        noRelocs = sectab_i->NumberOfRelocations;
        j = 0;
      }

      for (; j < noRelocs; j++) {
         COFF_symbol* sym;
         COFF_reloc* reltab_j
            = (COFF_reloc*)
              myindex ( sizeof_COFF_reloc, reltab, j );

         /* the location to patch */
         pP = (void*)(
                   (size_t)section.start
                 + reltab_j->VirtualAddress
                 - sectab_i->VirtualAddress
              );
         /* the existing contents of pP */
         A = *(uint32_t*)pP;
         /* the symbol to connect to */
         sym = (COFF_symbol*)
               myindex ( getSymbolSize (info),
                         symtab, reltab_j->SymbolTableIndex );
#if defined(x86_64_HOST_ARCH)
         uint64_t symIndex = ((uint64_t)myindex(getSymbolSize (info), symtab,
                                                reltab_j->SymbolTableIndex)
                                        - (uint64_t)symtab) / getSymbolSize (info);
#endif

         IF_DEBUG(linker,
                  debugBelch(
                            "reloc sec %2d num %3d:  type 0x%-4x   "
                            "vaddr 0x%-8lx   name `",
                            i, j,
                            (uint32_t)reltab_j->Type,
                            reltab_j->VirtualAddress );
                            printName ( getSymShortName (info, sym), strtab );
                            debugBelch("'\n" ));

         if (getSymStorageClass (info, sym) == IMAGE_SYM_CLASS_STATIC) {
            Section section = oc->sections[getSymSectionNumber (info, sym)-1];
            S = ((size_t)(section.start))
              + ((size_t)(getSymValue (info, sym)));
         } else {
            copyName ( getSymShortName (info, sym), strtab, symbol, 1000-1 );
            S = (size_t) lookupSymbol_( (char*)symbol );
            if ((void*)S == NULL) {
                errorBelch(" | %" PATH_FMT ": unknown symbol `%s'", oc->fileName, symbol);
                stgFree (info);
                return false;
            }
         }
         /* All supported relocations write at least 4 bytes */
         checkProddableBlock(oc, pP, 4);
         switch (reltab_j->Type) {
#if defined(i386_HOST_ARCH)
            case IMAGE_REL_I386_DIR32:
            case IMAGE_REL_I386_DIR32NB:
               *(uint32_t *)pP = ((uint32_t)S) + A;
               break;
            case IMAGE_REL_I386_REL32:
               /* Tricky.  We have to insert a displacement at
                  pP which, when added to the PC for the _next_
                  insn, gives the address of the target (S).
                  Problem is to know the address of the next insn
                  when we only know pP.  We assume that this
                  literal field is always the last in the insn,
                  so that the address of the next insn is pP+4
                  -- hence the constant 4.
                  Also I don't know if A should be added, but so
                  far it has always been zero.

                  SOF 05/2005: 'A' (old contents of *pP) have been observed
                  to contain values other than zero (the 'wx' object file
                  that came with wxhaskell-0.9.4; dunno how it was compiled..).
                  So, add displacement to old value instead of asserting
                  A to be zero. Fixes wxhaskell-related crashes, and no other
                  ill effects have been observed.

                  Update: the reason why we're seeing these more elaborate
                  relocations is due to a switch in how the NCG compiles SRTs
                  and offsets to them from info tables. SRTs live in .(ro)data,
                  while info tables live in .text, causing GAS to emit REL32/DISP32
                  relocations with non-zero values. Adding the displacement is
                  the right thing to do.
               */
               *(uint32_t *)pP = ((uint32_t)S) + A - ((uint32_t)(size_t)pP) - 4;
               break;
#elif defined(x86_64_HOST_ARCH)
            case 1: /* R_X86_64_64 (ELF constant 1) - IMAGE_REL_AMD64_ADDR64 (PE constant 1) */
               {
                   uint64_t A;
                   checkProddableBlock(oc, pP, 8);
                   A = *(uint64_t*)pP;
                   *(uint64_t *)pP = ((uint64_t)S) + ((uint64_t)A);
                   break;
               }
            case 2: /* R_X86_64_32 (ELF constant 10) - IMAGE_REL_AMD64_ADDR32 (PE constant 2) */
            case 3: /* R_X86_64_32S (ELF constant 11) - IMAGE_REL_AMD64_ADDR32NB (PE constant 3) */
            case 17: /* R_X86_64_32S ELF constant, no PE mapping. See note [ELF constant in PE file] */
               {
                   size_t v;
                   v = S + ((size_t)A);
                   if (v >> 32) {
                       copyName ( getSymShortName (info, sym), strtab, symbol, 1000-1 );
                       S = makeSymbolExtra_PEi386(oc, symIndex, S, (char *)symbol);
                       /* And retry */
                       v = S + ((size_t)A);
                       if (v >> 32) {
                           barf("IMAGE_REL_AMD64_ADDR32[NB]: High bits are set in %zx for %s",
                                v, (char *)symbol);
                       }
                   }
                   *(uint32_t *)pP = (uint32_t)v;
                   break;
               }
            case 4: /* R_X86_64_PC32 (ELF constant 2) - IMAGE_REL_AMD64_REL32 (PE constant 4) */
               {
                   intptr_t v;
                   v = ((intptr_t)S) + ((intptr_t)(int32_t)A) - ((intptr_t)pP) - 4;
                   if ((v >> 32) && ((-v) >> 32)) {
                       /* Make the trampoline then */
                       copyName ( getSymShortName (info, sym), strtab, symbol, 1000-1 );
                       S = makeSymbolExtra_PEi386(oc, symIndex, S, (char *)symbol);
                       /* And retry */
                       v = ((intptr_t)S) + ((intptr_t)(int32_t)A) - ((intptr_t)pP) - 4;
                       if ((v >> 32) && ((-v) >> 32)) {
                           barf("IMAGE_REL_AMD64_REL32: High bits are set in %zx for %s",
                                v, (char *)symbol);
                       }
                   }
                   *(uint32_t *)pP = (uint32_t)v;
                   break;
               }
#endif
            default:
               debugBelch("%" PATH_FMT ": unhandled PEi386 relocation type %d\n",
                     oc->fileName, reltab_j->Type);
               stgFree (info);
               return false;
         }

      }
   }

   stgFree (info);
   IF_DEBUG(linker, debugBelch("completed %" PATH_FMT "\n", oc->fileName));
   return true;
}

/*
  Note [ELF constant in PE file]

  For some reason, the PE files produced by GHC contain a linux
  relocation constant 17 (0x11) in the object files. As far as I (Phyx-) can tell
  this constant doesn't seem like it's coming from GHC, or at least I could not find
  anything in the .s output that GHC produces which specifies the relocation type.

  This leads me to believe that this is a bug in GAS. However because this constant is
  there we must deal with it. This is done by mapping it to the equivalent in behaviour PE
  relocation constant 0x03.

  See #9907
*/

bool
ocRunInit_PEi386 ( ObjectCode *oc )
{
    COFF_section* sectab;
    uint8_t*        strtab;
    unsigned int i;

    COFF_HEADER_INFO *info = getHeaderInfo (oc);
    sectab = (COFF_section*) (
                ((uint8_t*)(oc->image))
                + info->sizeOfHeader + info->sizeOfOptionalHeader
             );
    strtab = ((uint8_t*)(oc->image))
             + info->pointerToSymbolTable
             + info->numberOfSymbols * getSymbolSize (info);

    int argc, envc;
    char **argv, **envv;

    getProgArgv(&argc, &argv);
    getProgEnvv(&envc, &envv);

    /* TODO: This part is just looking for .ctors section. This can be optimized
       and should for objects compiled with function sections as these produce a
       large amount of sections.

       This can be done by saving the index of the .ctor section in the ObjectCode
       from ocGetNames. Then this loop isn't needed. */
    for (i = 0; i < info->numberOfSections; i++) {
        COFF_section* sectab_i
            = (COFF_section*)
                myindex ( sizeof_COFF_section, sectab, i );
        Section section = oc->sections[i];
        char *secname = cstring_from_section_name(sectab_i->Name, strtab);
        if (0 == strcmp(".ctors", (char*)secname)) {
            uint8_t *init_startC = section.start;
            init_t *init_start, *init_end, *init;
            init_start = (init_t*)init_startC;
            init_end = (init_t*)(init_startC + sectab_i->SizeOfRawData);
            // ctors are run *backwards*!
            for (init = init_end - 1; init >= init_start; init--) {
                (*init)(argc, argv, envv);
            }
        }
    }
    stgFree (info);
    freeProgEnvv(envc, envv);
    return true;
}

SymbolAddr *lookupSymbol_PEi386(SymbolName *lbl)
{
    RtsSymbolInfo *pinfo;

    if (!ghciLookupSymbolInfo(symhash, lbl, &pinfo)) {
        IF_DEBUG(linker, debugBelch("lookupSymbol: symbol '%s' not found\n", lbl));

        SymbolAddr* sym;

/* See Note [mingw-w64 name decoration scheme] */
#if !defined(x86_64_HOST_ARCH)
        zapTrailingAtSign ( (unsigned char*)lbl );
#endif
        sym = lookupSymbolInDLLs((unsigned char*)lbl);
        return sym; // might be NULL if not found
    } else {
#if defined(mingw32_HOST_OS)
        // If Windows, perform initialization of uninitialized
        // Symbols from the C runtime which was loaded above.
        // We do this on lookup to prevent the hit when
        // The symbol isn't being used.
        if (pinfo->value == (void*)0xBAADF00D)
        {
            char symBuffer[50];
            sprintf(symBuffer, "_%s", lbl);
            pinfo->value = GetProcAddress(GetModuleHandle("msvcrt"), symBuffer);
        }
        else if (pinfo && pinfo->owner && isSymbolImport (pinfo->owner, lbl))
        {
            /* See Note [BFD import library].  */
            HINSTANCE dllInstance = (HINSTANCE)lookupSymbol(pinfo->value);
            if (!dllInstance && pinfo->value)
               return pinfo->value;

            if (!dllInstance)
            {
               errorBelch("Unable to load import dll symbol `%s'. "
                          "No _iname symbol.", lbl);
               return NULL;
            }
            IF_DEBUG(linker,
               debugBelch("indexing import %s => %s using dll instance %p\n",
                   lbl, (char*)pinfo->value, dllInstance));
            pinfo->value = GetProcAddress((HMODULE)dllInstance, lbl);
            clearImportSymbol (pinfo->owner, lbl);
            return pinfo->value;
        }
#endif
        return loadSymbol(lbl, pinfo);
    }
}

#endif /* mingw32_HOST_OS */