gcc/config/arm/linux-elf.h

   1 /* Definitions for ARM running Linux-based GNU systems using ELF
   2    Copyright (C) 1993, 1994, 1997, 1998, 1999 Free Software Foundation, Inc.
   3    Contributed by Philip Blundell <philb@gnu.org>
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU CC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* Run-time Target Specification.  */
  23 #define TARGET_VERSION  fputs (" (ARM GNU/Linux with ELF)", stderr);
  24
  25 /* We have libgcc2.  */
  26 #define HAVE_ATEXIT
  27
  28 /* Default is to use APCS-32 mode.  */
  29 #ifndef SUBTARGET_DEFAULT_APCS26
  30 #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_SHORT_BYTE)
  31 #define SUBTARGET_EXTRA_LINK_SPEC       \
  32         " %{mapcs-26:-m elf32arm26} %{!mapcs-26:-m elf32arm}"
  33 #define SUBTARGET_EXTRA_ASM_SPEC        \
  34         " %{mapcs-26:-mapcs-26} %(!mapcs-26:-mapcs-32}"
  35 #endif
  36
  37 /* This was defined in linux.h.  Define it here also. */
  38 #undef  DEFAULT_VTABLE_THUNKS
  39 #define DEFAULT_VTABLE_THUNKS   1
  40
  41 /* Handle #pragma weak and #pragma pack.  */
  42 #define HANDLE_SYSV_PRAGMA
  43
  44 /* Now we define the strings used to build the spec file.  */
  45 #define LIB_SPEC \
  46   "%{shared: -lc} \
  47    %{!shared: %{pthread:-lpthread} \
  48         %{profile:-lc_p} %{!profile: -lc}}"
  49
  50 #define LIBGCC_SPEC "%{msoft-float:-lfloat} -lgcc"
  51
  52 /* Provide a STARTFILE_SPEC appropriate for GNU/Linux.  Here we add
  53    the GNU/Linux magical crtbegin.o file (see crtstuff.c) which
  54    provides part of the support for getting C++ file-scope static
  55    object constructed before entering `main'. */
  56
  57 #define STARTFILE_SPEC \
  58   "%{!shared: \
  59      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} \
  60                        %{!p:%{profile:gcrt1.o%s} \
  61                          %{!profile:crt1.o%s}}}} \
  62    crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}"
  63
  64 /* Provide a ENDFILE_SPEC appropriate for GNU/Linux.  Here we tack on
  65    the GNU/Linux magical crtend.o file (see crtstuff.c) which
  66    provides part of the support for getting C++ file-scope static
  67    object constructed before entering `main', followed by a normal
  68    GNU/Linux "finalizer" file, `crtn.o'.  */
  69
  70 #define ENDFILE_SPEC \
  71   "%{!shared:crtend.o%s} %{shared:crtendS.o%s} crtn.o%s"
  72
  73 #define LINK_SPEC "%{h*} %{version:-v} \
  74    %{b} %{Wl,*:%*} \
  75    %{static:-Bstatic} \
  76    %{shared:-shared} \
  77    %{symbolic:-Bsymbolic} \
  78    %{rdynamic:-export-dynamic} \
  79    %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2} \
  80    -X \
  81    %{mbig-endian:-EB}" \
  82    SUBTARGET_EXTRA_LINK_SPEC
  83
  84 #undef  CPP_PREDEFINES
  85 #define CPP_PREDEFINES \
  86 "-Dunix -Darm -Dlinux -Asystem(unix) -Asystem(posix) -Acpu(arm) \
  87 -Amachine(arm) -D__ELF__ -Darm_elf"
  88
  89 #ifndef SUBTARGET_DEFAULT_APCS26
  90 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  91 #endif
  92
  93 /* Allow #sccs in preprocessor.  */
  94 #define SCCS_DIRECTIVE
  95
  96 #define USER_LABEL_PREFIX       ""      /* For ELF the default is no underscores */
  97 #define LOCAL_LABEL_PREFIX      "."
  98
  99 /* Attach a special .ident directive to the end of the file to identify
 100    the version of GCC which compiled this code.  */
 101 #define IDENT_ASM_OP    ".ident"
 102
 103 /* Output #ident as a .ident.  */
 104 #define ASM_OUTPUT_IDENT(FILE, NAME) \
 105   fprintf (FILE, "\t%s\t\"%s\"\n", IDENT_ASM_OP, NAME);
 106
 107 #ifdef IDENTIFY_WITH_IDENT
 108 #define ASM_IDENTIFY_GCC(FILE) /* nothing */
 109 #define ASM_IDENTIFY_LANGUAGE(FILE)                     \
 110  fprintf (FILE, "\t%s \"GCC (%s) %s\"\n", IDENT_ASM_OP, \
 111          lang_identify (), version_string)
 112 #else
 113 #define ASM_FILE_END(FILE)                                      \
 114 do {                                                            \
 115      if (!flag_no_ident)                                        \
 116         fprintf ((FILE), "\t%s\t\"GCC: (GNU) %s\"\n",           \
 117                  IDENT_ASM_OP, version_string);                 \
 118    } while (0)
 119 #endif
 120
 121 /* Support const sections and the ctors and dtors sections for g++.
 122    Note that there appears to be two different ways to support const
 123    sections at the moment.  You can either #define the symbol
 124    READONLY_DATA_SECTION (giving it some code which switches to the
 125    readonly data section) or else you can #define the symbols
 126    EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
 127    SELECT_RTX_SECTION.  We do both here just to be on the safe side.  */
 128 #define USE_CONST_SECTION       1
 129
 130 /* Support for Constructors and Destructors.  */
 131 #define READONLY_DATA_SECTION() const_section ()
 132
 133 /* A default list of other sections which we might be "in" at any given
 134    time.  For targets that use additional sections (e.g. .tdesc) you
 135    should override this definition in the target-specific file which
 136    includes this file.  */
 137 #define SUBTARGET_EXTRA_SECTIONS in_const,
 138
 139 /* A default list of extra section function definitions.  For targets
 140    that use additional sections (e.g. .tdesc) you should override this
 141    definition in the target-specific file which includes this file.  */
 142 #define SUBTARGET_EXTRA_SECTION_FUNCTIONS       CONST_SECTION_FUNCTION
 143
 144 extern void text_section ();
 145
 146 #define CONST_SECTION_ASM_OP    ".section\t.rodata"
 147
 148 #define CONST_SECTION_FUNCTION                                          \
 149 void                                                                    \
 150 const_section ()                                                        \
 151 {                                                                       \
 152   if (!USE_CONST_SECTION)                                               \
 153     text_section ();                                                    \
 154   else if (in_section != in_const)                                      \
 155     {                                                                   \
 156       fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);             \
 157       in_section = in_const;                                            \
 158     }                                                                   \
 159 }
 160
 161 /* Switch into a generic section.
 162    This is currently only used to support section attributes.
 163
 164    We make the section read-only and executable for a function decl,
 165    read-only for a const data decl, and writable for a non-const data decl.  */
 166 #define ASM_OUTPUT_SECTION_NAME(FILE, DECL, NAME, RELOC) \
 167   fprintf (FILE, ".section\t%s,\"%s\",%%progbits\n", NAME, \
 168            (DECL) && TREE_CODE (DECL) == FUNCTION_DECL ? "ax" : \
 169            (DECL) && DECL_READONLY_SECTION (DECL, RELOC) ? "a" : "aw")
 170
 171 /* A C statement or statements to switch to the appropriate
 172    section for output of DECL.  DECL is either a `VAR_DECL' node
 173    or a constant of some sort.  RELOC indicates whether forming
 174    the initial value of DECL requires link-time relocations.  */
 175 #define SELECT_SECTION(DECL,RELOC)                                      \
 176 {                                                                       \
 177   if (TREE_CODE (DECL) == STRING_CST)                                   \
 178     {                                                                   \
 179       if (! flag_writable_strings)                                      \
 180         const_section ();                                               \
 181       else                                                              \
 182         data_section ();                                                \
 183     }                                                                   \
 184   else if (TREE_CODE (DECL) == VAR_DECL)                                \
 185     {                                                                   \
 186       if ((flag_pic && RELOC)                                           \
 187           || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)          \
 188           || !DECL_INITIAL (DECL)                                       \
 189           || (DECL_INITIAL (DECL) != error_mark_node                    \
 190               && !TREE_CONSTANT (DECL_INITIAL (DECL))))                 \
 191         data_section ();                                                \
 192       else                                                              \
 193         const_section ();                                               \
 194     }                                                                   \
 195   else                                                                  \
 196     const_section ();                                                   \
 197 }
 198
 199 /* A C statement or statements to switch to the appropriate
 200    section for output of RTX in mode MODE.  RTX is some kind
 201    of constant in RTL.  The argument MODE is redundant except
 202    in the case of a `const_int' rtx.  Currently, these always
 203    go into the const section.  */
 204 #define SELECT_RTX_SECTION(MODE,RTX) const_section ()
 205
 206 /* On svr4, we *do* have support for the .init and .fini sections, and we
 207    can put stuff in there to be executed before and after `main'.  We let
 208    crtstuff.c and other files know this by defining the following symbols.
 209    The definitions say how to change sections to the .init and .fini
 210    sections.  This is the same for all known svr4 assemblers.  */
 211 #define INIT_SECTION_ASM_OP     ".section\t.init"
 212 #define FINI_SECTION_ASM_OP     ".section\t.fini"
 213
 214
 215 /* This is how we tell the assembler that a symbol is weak.  */
 216 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 217   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 218        fputc ('\n', FILE); } while (0)
 219
 220 /* This is how we tell the assembler that two symbols have the same value.  */
 221
 222 #define ASM_OUTPUT_DEF(FILE,NAME1,NAME2) \
 223   do { assemble_name (FILE, NAME1);      \
 224        fputs (" = ", FILE);              \
 225        assemble_name (FILE, NAME2);      \
 226        fputc ('\n', FILE); } while (0)
 227
 228 /* Make DWARF2 an option, but keep DBX as the default for now.
 229    Use -gdwarf-2 to turn on DWARF2.  */
 230 #define DWARF2_DEBUGGING_INFO
 231 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
 232
 233 /* Get the standard ELF stabs definitions.  */
 234 #include "dbxelf.h"
 235
 236 #include "arm/elf.h"
 237 #include "arm/linux-gas.h"
 238
 239 #ifndef SUBTARGET_DEFAULT_APCS26
 240 /* On 32-bit machine it is always safe to assume we have the "new"
 241    floating point system.
 242    ?? Make this happen for all targets when NWFPE is better established.  */
 243 #undef  FP_DEFAULT
 244 #define FP_DEFAULT FP_SOFT3
 245 #endif