winnt.c

gcc-you can use this code to learn something about gcc, and inquire further into linux,

     and compare the string's addresses to see if two symbols are
     identical.  */
  idp = get_identifier (newname);

  newrtl = gen_rtx (MEM, Pmode,
		    gen_rtx (SYMBOL_REF, Pmode,
			     IDENTIFIER_POINTER (idp)));
  XEXP (DECL_RTL (decl), 0) = newrtl;

  /* Can't treat a pointer to this as a constant address */
  DECL_NON_ADDR_CONST_P (decl) = 1;
}

/* Return string which is the former assembler name modified with a 
   suffix consisting of an atsign (@) followed by the number of bytes of 
   arguments */

const char *
gen_stdcall_suffix (decl)
  tree decl;
{
  int total = 0;
  /* ??? This probably should use XSTR (XEXP (DECL_RTL (decl), 0), 0) instead
     of DECL_ASSEMBLER_NAME.  */
  const char *asmname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
  char *newsym;

  if (TYPE_ARG_TYPES (TREE_TYPE (decl)))
    if (TREE_VALUE (tree_last (TYPE_ARG_TYPES (TREE_TYPE (decl)))) 
        == void_type_node)
      {
	tree formal_type = TYPE_ARG_TYPES (TREE_TYPE (decl));

	while (TREE_VALUE (formal_type) != void_type_node)
	  {
	    int parm_size
	      = TREE_INT_CST_LOW (TYPE_SIZE (TREE_VALUE (formal_type)));
	    /* Must round up to include padding.  This is done the same
	       way as in store_one_arg.  */
	    parm_size = ((parm_size + PARM_BOUNDARY - 1)
			 / PARM_BOUNDARY * PARM_BOUNDARY);
	    total += parm_size;
	    formal_type = TREE_CHAIN (formal_type);
	  }
      }

  newsym = xmalloc (strlen (asmname) + 10);
  sprintf (newsym, "%s@%d", asmname, total/BITS_PER_UNIT);
  return IDENTIFIER_POINTER (get_identifier (newsym));
}

void
i386_pe_encode_section_info (decl, first)
     tree decl;
     int first ATTRIBUTE_UNUSED;
{
  /* This bit is copied from i386.h.  */
  if (optimize > 0 && TREE_CONSTANT (decl)
      && (!flag_writable_strings || TREE_CODE (decl) != STRING_CST))
    {
      rtx rtl = (TREE_CODE_CLASS (TREE_CODE (decl)) != 'd'
                 ? TREE_CST_RTL (decl) : DECL_RTL (decl));
      SYMBOL_REF_FLAG (XEXP (rtl, 0)) = 1;
    }

  if (TREE_CODE (decl) == FUNCTION_DECL)
    if (lookup_attribute ("stdcall",
			  TYPE_ATTRIBUTES (TREE_TYPE (decl))))
      XEXP (DECL_RTL (decl), 0) = 
	gen_rtx (SYMBOL_REF, Pmode, gen_stdcall_suffix (decl));

  /* Mark the decl so we can tell from the rtl whether the object is
     dllexport'd or dllimport'd.  This also handles dllexport/dllimport
     override semantics.  */

  if (i386_pe_dllexport_p (decl))
    i386_pe_mark_dllexport (decl);
  else if (i386_pe_dllimport_p (decl))
    i386_pe_mark_dllimport (decl);
  /* It might be that DECL has already been marked as dllimport, but a
     subsequent definition nullified that.  The attribute is gone but
     DECL_RTL still has (DLL_IMPORT_EXPORT_PREFIX)i._imp__foo.  We need
     to remove that. Ditto for the DECL_NON_ADDR_CONST_P flag.  */
  else if ((TREE_CODE (decl) == FUNCTION_DECL
	    || TREE_CODE (decl) == VAR_DECL)
	   && DECL_RTL (decl) != NULL_RTX
	   && GET_CODE (DECL_RTL (decl)) == MEM
	   && GET_CODE (XEXP (DECL_RTL (decl), 0)) == MEM
	   && GET_CODE (XEXP (XEXP (DECL_RTL (decl), 0), 0)) == SYMBOL_REF
	   && i386_pe_dllimport_name_p (XSTR (XEXP (XEXP (DECL_RTL (decl), 0), 0), 0)))
    {
      const char *oldname = XSTR (XEXP (XEXP (DECL_RTL (decl), 0), 0), 0);
      tree idp = get_identifier (oldname + 9);
      rtx newrtl = gen_rtx (SYMBOL_REF, Pmode, IDENTIFIER_POINTER (idp));

      warning_with_decl (decl, "'%s' %s after being referenced with dllimport linkage.",
	         	 (DECL_INITIAL (decl) || !DECL_EXTERNAL (decl))
			 ? "defined locally" : "redeclared without dllimport attribute");

      XEXP (DECL_RTL (decl), 0) = newrtl;

      DECL_NON_ADDR_CONST_P (decl) = 0;

      /* We previously set TREE_PUBLIC and DECL_EXTERNAL.
	 We leave these alone for now.  */
    }
}

/* Strip only the leading encoding, leaving the stdcall suffix.  */

const char *
i386_pe_strip_name_encoding (str)
     const char *str;
{
  if (*str == DLL_IMPORT_EXPORT_PREFIX)
    str += 3;
  if (*str == '*')
    str += 1;
  return str;
}

/* Also strip the stdcall suffix.  */

const char *
i386_pe_strip_name_encoding_full (str)
     const char *str;
{
  const char *p;
  const char *name = i386_pe_strip_name_encoding (str);
 
  p = strchr (name, '@');
  if (p)
    return ggc_alloc_string (name, p - name);

  return name;
}

void
i386_pe_unique_section (decl, reloc)
     tree decl;
     int reloc;
{
  int len;
  const char *name, *prefix;
  char *string;

  name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
  name = i386_pe_strip_name_encoding_full (name);

  /* The object is put in, for example, section .text$foo.
     The linker will then ultimately place them in .text
     (everything from the $ on is stripped). Don't put
     read-only data in .rdata section to avoid a PE linker 
     bug when .rdata$* grouped sections are used in code
     without a .rdata section.  */
  if (TREE_CODE (decl) == FUNCTION_DECL)
    prefix = ".text$";
  else if (decl_readonly_section (decl, reloc))
    prefix = ".rdata$";
  else
    prefix = ".data$";
  len = strlen (name) + strlen (prefix);
  string = alloca (len + 1);
  sprintf (string, "%s%s", prefix, name);

  DECL_SECTION_NAME (decl) = build_string (len, string);
}

/* Select a set of attributes for section NAME based on the properties
   of DECL and whether or not RELOC indicates that DECL's initializer
   might contain runtime relocations.

   We make the section read-only and executable for a function decl,
   read-only for a const data decl, and writable for a non-const data decl.

   If the section has already been defined, to not allow it to have
   different attributes, as (1) this is ambiguous since we're not seeing
   all the declarations up front and (2) some assemblers (e.g. SVR4)
   do not recoginize section redefinitions.  */
/* ??? This differs from the "standard" PE implementation in that we
   handle the SHARED variable attribute.  Should this be done for all
   PE targets?  */

#define SECTION_PE_SHARED	SECTION_MACH_DEP

unsigned int
i386_pe_section_type_flags (decl, name, reloc)
     tree decl;
     const char *name;
     int reloc;
{
  static htab_t htab;
  unsigned int flags;
  unsigned int **slot;

  /* The names we put in the hashtable will always be the unique
     versions gived to us by the stringtable, so we can just use
     their addresses as the keys.  */
  if (!htab)
    htab = htab_create (31, htab_hash_pointer, htab_eq_pointer, NULL);

  if (decl && TREE_CODE (decl) == FUNCTION_DECL)
    flags = SECTION_CODE;
  else if (decl && decl_readonly_section (decl, reloc))
    flags = 0;
  else
    {
      flags = SECTION_WRITE;

      if (decl && TREE_CODE (decl) == VAR_DECL
	  && lookup_attribute ("shared", DECL_ATTRIBUTES (decl)))
	flags |= SECTION_PE_SHARED;
    }

  if (decl && DECL_ONE_ONLY (decl))
    flags |= SECTION_LINKONCE;

  /* See if we already have an entry for this section.  */
  slot = (unsigned int **) htab_find_slot (htab, name, INSERT);
  if (!*slot)
    {
      *slot = (unsigned int *) xmalloc (sizeof (unsigned int));
      **slot = flags;
    }
  else
    {
      if (decl && **slot != flags)
	error_with_decl (decl, "%s causes a section type conflict");
    }

  return flags;
}

void
i386_pe_asm_named_section (name, flags)
     const char *name;
     unsigned int flags;
{
  char flagchars[8], *f = flagchars;

  if (flags & SECTION_CODE)
    *f++ = 'x';
  if (flags & SECTION_WRITE)
    *f++ = 'w';
  if (flags & SECTION_PE_SHARED)
    *f++ = 's';
  *f = '\0';

  fprintf (asm_out_file, "\t.section\t%s,\"%s\"\n", name, flagchars);

  if (flags & SECTION_LINKONCE)
    {
      /* Functions may have been compiled at various levels of
         optimization so we can't use `same_size' here.
         Instead, have the linker pick one.  */
      fprintf (asm_out_file, "\t.linkonce %s\n",
	       (flags & SECTION_CODE ? "discard" : "same_size"));
    }
}

/* The Microsoft linker requires that every function be marked as
   DT_FCN.  When using gas on cygwin, we must emit appropriate .type
   directives.  */

#include "gsyms.h"

/* Mark a function appropriately.  This should only be called for
   functions for which we are not emitting COFF debugging information.
   FILE is the assembler output file, NAME is the name of the
   function, and PUBLIC is nonzero if the function is globally
   visible.  */

void
i386_pe_declare_function_type (file, name, public)
     FILE *file;
     const char *name;
     int public;
{
  fprintf (file, "\t.def\t");
  assemble_name (file, name);
  fprintf (file, ";\t.scl\t%d;\t.type\t%d;\t.endef\n",
	   public ? (int) C_EXT : (int) C_STAT,
	   (int) DT_FCN << N_BTSHFT);
}

/* Keep a list of external functions.  */

struct extern_list
{
  struct extern_list *next;
  const char *name;
};

static struct extern_list *extern_head;

/* Assemble an external function reference.  We need to keep a list of
   these, so that we can output the function types at the end of the
   assembly.  We can't output the types now, because we might see a
   definition of the function later on and emit debugging information
   for it then.  */

void
i386_pe_record_external_function (name)
     const char *name;
{
  struct extern_list *p;

  p = (struct extern_list *) xmalloc (sizeof *p);
  p->next = extern_head;
  p->name = name;
  extern_head = p;
}

/* Keep a list of exported symbols.  */

struct export_list
{
  struct export_list *next;
  const char *name;
  int is_data;		/* used to type tag exported symbols.  */
};

static struct export_list *export_head;

/* Assemble an export symbol entry.  We need to keep a list of
   these, so that we can output the export list at the end of the
   assembly.  We used to output these export symbols in each function,
   but that causes problems with GNU ld when the sections are 
   linkonce.  */

void
i386_pe_record_exported_symbol (name, is_data)
     const char *name;
     int is_data;
{
  struct export_list *p;

  p = (struct export_list *) xmalloc (sizeof *p);
  p->next = export_head;
  p->name = name;
  p->is_data = is_data;
  export_head = p;
}

/* This is called at the end of assembly.  For each external function
   which has not been defined, we output a declaration now.  We also
   output the .drectve section.  */

void
i386_pe_asm_file_end (file)
     FILE *file;
{
  struct extern_list *p;

  ix86_asm_file_end (file);

  for (p = extern_head; p != NULL; p = p->next)
    {
      tree decl;

      decl = get_identifier (p->name);

      /* Positively ensure only one declaration for any given symbol.  */
      if (! TREE_ASM_WRITTEN (decl) && TREE_SYMBOL_REFERENCED (decl))
	{
	  TREE_ASM_WRITTEN (decl) = 1;
	  i386_pe_declare_function_type (file, p->name, TREE_PUBLIC (decl));
	}
    }

  if (export_head)
    {
      struct export_list *q;
      drectve_section ();
      for (q = export_head; q != NULL; q = q->next)
	{
	  fprintf (file, "\t.ascii \" -export:%s%s\"\n",
		   i386_pe_strip_name_encoding (q->name),
		   (q->is_data) ? ",data" : "");
	}
    }
}