gcc/config/i386/freebsd-elf.h

   1 /* Definitions for Intel 386 running FreeBSD with ELF format
   2    Copyright (C) 1996 Free Software Foundation, Inc.
   3    Contributed by Eric Youngdale.
   4    Modified for stabs-in-ELF by H.J. Lu.
   5    Adapted from GNU/Linux version by John Polstra.
   6    Continued development by David O'Brien <obrien@freebsd.org>
   7
   8 This file is part of GNU CC.
   9
  10 GNU CC is free software; you can redistribute it and/or modify
  11 it under the terms of the GNU General Public License as published by
  12 the Free Software Foundation; either version 2, or (at your option)
  13 any later version.
  14
  15 GNU CC is distributed in the hope that it will be useful,
  16 but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 GNU General Public License for more details.
  19
  20 You should have received a copy of the GNU General Public License
  21 along with GNU CC; see the file COPYING.  If not, write to
  22 the Free Software Foundation, 59 Temple Place - Suite 330,
  23 Boston, MA 02111-1307, USA.  */
  24
  25 #undef TARGET_VERSION
  26 #define TARGET_VERSION fprintf (stderr, " (i386 FreeBSD/ELF)");
  27
  28 /* The svr4 ABI for the i386 says that records and unions are returned
  29    in memory.  */
  30 /* On FreeBSD, we do not. */
  31 #undef DEFAULT_PCC_STRUCT_RETURN
  32 #define DEFAULT_PCC_STRUCT_RETURN 0
  33
  34 /* This gets defined in tm.h->linux.h->svr4.h, and keeps us from using
  35    libraries compiled with the native cc, so undef it. */
  36 #undef NO_DOLLAR_IN_LABEL
  37
  38 /* Use more efficient ``thunks'' to implement C++ vtables. */
  39 #undef DEFAULT_VTABLE_THUNKS
  40 #define DEFAULT_VTABLE_THUNKS 1
  41
  42 /* Override the default comment-starter of "/".  */
  43 #undef ASM_COMMENT_START
  44 #define ASM_COMMENT_START "#"
  45
  46 #undef ASM_APP_ON
  47 #define ASM_APP_ON "#APP\n"
  48
  49 #undef ASM_APP_OFF
  50 #define ASM_APP_OFF "#NO_APP\n"
  51
  52 #undef SET_ASM_OP
  53 #define SET_ASM_OP      ".set"
  54
  55 /* This is how to output an element of a case-vector that is relative.
  56    This is only used for PIC code.  See comments by the `casesi' insn in
  57    i386.md for an explanation of the expression this outputs. */
  58 #undef ASM_OUTPUT_ADDR_DIFF_ELT
  59 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, BODY, VALUE, REL) \
  60   fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
  61
  62 /* Indicate that jump tables go in the text section.  This is
  63    necessary when compiling PIC code.  */
  64 #define JUMP_TABLES_IN_TEXT_SECTION (flag_pic)
  65
  66 /* Use stabs instead of DWARF debug format.  */
  67 #undef PREFERRED_DEBUGGING_TYPE
  68 #define PREFERRED_DEBUGGING_TYPE DBX_DEBUG
  69
  70 /* Copy this from the svr4 specifications... */
  71 /* Define the register numbers to be used in Dwarf debugging information.
  72    The SVR4 reference port C compiler uses the following register numbers
  73    in its Dwarf output code:
  74         0 for %eax (gnu regno = 0)
  75         1 for %ecx (gnu regno = 2)
  76         2 for %edx (gnu regno = 1)
  77         3 for %ebx (gnu regno = 3)
  78         4 for %esp (gnu regno = 7)
  79         5 for %ebp (gnu regno = 6)
  80         6 for %esi (gnu regno = 4)
  81         7 for %edi (gnu regno = 5)
  82    The following three DWARF register numbers are never generated by
  83    the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
  84    believes these numbers have these meanings.
  85         8  for %eip    (no gnu equivalent)
  86         9  for %eflags (no gnu equivalent)
  87         10 for %trapno (no gnu equivalent)
  88    It is not at all clear how we should number the FP stack registers
  89    for the x86 architecture.  If the version of SDB on x86/svr4 were
  90    a bit less brain dead with respect to floating-point then we would
  91    have a precedent to follow with respect to DWARF register numbers
  92    for x86 FP registers, but the SDB on x86/svr4 is so completely
  93    broken with respect to FP registers that it is hardly worth thinking
  94    of it as something to strive for compatibility with.
  95    The version of x86/svr4 SDB I have at the moment does (partially)
  96    seem to believe that DWARF register number 11 is associated with
  97    the x86 register %st(0), but that's about all.  Higher DWARF
  98    register numbers don't seem to be associated with anything in
  99    particular, and even for DWARF regno 11, SDB only seems to under-
 100    stand that it should say that a variable lives in %st(0) (when
 101    asked via an `=' command) if we said it was in DWARF regno 11,
 102    but SDB still prints garbage when asked for the value of the
 103    variable in question (via a `/' command).
 104    (Also note that the labels SDB prints for various FP stack regs
 105    when doing an `x' command are all wrong.)
 106    Note that these problems generally don't affect the native SVR4
 107    C compiler because it doesn't allow the use of -O with -g and
 108    because when it is *not* optimizing, it allocates a memory
 109    location for each floating-point variable, and the memory
 110    location is what gets described in the DWARF AT_location
 111    attribute for the variable in question.
 112    Regardless of the severe mental illness of the x86/svr4 SDB, we
 113    do something sensible here and we use the following DWARF
 114    register numbers.  Note that these are all stack-top-relative
 115    numbers.
 116         11 for %st(0) (gnu regno = 8)
 117         12 for %st(1) (gnu regno = 9)
 118         13 for %st(2) (gnu regno = 10)
 119         14 for %st(3) (gnu regno = 11)
 120         15 for %st(4) (gnu regno = 12)
 121         16 for %st(5) (gnu regno = 13)
 122         17 for %st(6) (gnu regno = 14)
 123         18 for %st(7) (gnu regno = 15)
 124 */
 125 #undef DBX_REGISTER_NUMBER
 126 #define DBX_REGISTER_NUMBER(n) \
 127 ((n) == 0 ? 0 \
 128  : (n) == 1 ? 2 \
 129  : (n) == 2 ? 1 \
 130  : (n) == 3 ? 3 \
 131  : (n) == 4 ? 6 \
 132  : (n) == 5 ? 7 \
 133  : (n) == 6 ? 5 \
 134  : (n) == 7 ? 4 \
 135  : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
 136  : (-1))
 137
 138 /* Tell final.c that we don't need a label passed to mcount.  */
 139
 140 #undef FUNCTION_PROFILER
 141 #define FUNCTION_PROFILER(FILE, LABELNO)  \
 142 {                                                                       \
 143   if (flag_pic)                                                         \
 144       fprintf (FILE, "\tcall *.mcount@GOT(%%ebx)\n");                   \
 145   else                                                                  \
 146       fprintf (FILE, "\tcall .mcount\n");                               \
 147 }
 148
 149 #undef SIZE_TYPE
 150 #define SIZE_TYPE "unsigned int"
 151
 152 #undef PTRDIFF_TYPE
 153 #define PTRDIFF_TYPE "int"
 154
 155 #undef WCHAR_TYPE
 156 #define WCHAR_TYPE "int"
 157
 158 #undef WCHAR_UNSIGNED
 159 #define WCHAR_UNSIGNED 0
 160
 161 #undef WCHAR_TYPE_SIZE
 162 #define WCHAR_TYPE_SIZE BITS_PER_WORD
 163
 164 #undef CPP_PREDEFINES
 165 #define CPP_PREDEFINES "-Di386 -Dunix -D__ELF__ -D__FreeBSD__ -Asystem(unix) -Asystem(FreeBSD) -Acpu(i386) -Amachine(i386)"
 166
 167 #undef CPP_SPEC
 168 #define CPP_SPEC "%(cpp_cpu) %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE}"
 169
 170 /* This defines which switch letters take arguments.  On FreeBSD, most of
 171    the normal cases (defined in gcc.c) apply, and we also have -h* and
 172    -z* options (for the linker) (comming from svr4).
 173    We also have -R (alias --rpath), no -z, --soname (-h), --assert etc. */
 174
 175 #undef SWITCH_TAKES_ARG
 176 #define SWITCH_TAKES_ARG(CHAR) \
 177   (DEFAULT_SWITCH_TAKES_ARG (CHAR) \
 178    || (CHAR) == 'h' \
 179    || (CHAR) == 'z' \
 180    || (CHAR) == 'R')
 181
 182 /* Provide a STARTFILE_SPEC appropriate for FreeBSD.  Here we add
 183    the magical crtbegin.o file (see crtstuff.c) which provides part
 184         of the support for getting C++ file-scope static object constructed
 185         before entering `main'. */
 186
 187 #undef  STARTFILE_SPEC
 188 #define STARTFILE_SPEC \
 189   "%{!shared: \
 190      %{pg:gcrt1.o%s} %{!pg:%{p:gcrt1.o%s} \
 191                        %{!p:%{profile:gcrt1.o%s} \
 192                          %{!profile:crt1.o%s}}}} \
 193    crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}"
 194
 195 /* Provide a ENDFILE_SPEC appropriate for FreeBSD.  Here we tack on
 196    the magical crtend.o file (see crtstuff.c) which provides part of
 197         the support for getting C++ file-scope static object constructed
 198         before entering `main', followed by a normal "finalizer" file,
 199         `crtn.o'.  */
 200
 201 #undef  ENDFILE_SPEC
 202 #define ENDFILE_SPEC \
 203   "%{!shared:crtend.o%s} %{shared:crtendS.o%s} crtn.o%s"
 204
 205 /* Provide a LIB_SPEC appropriate for FreeBSD.  Just select the appropriate
 206    libc, depending on whether we're doing profiling or need threads support.
 207    (simular to the default, except no -lg, and no -p.  */
 208
 209 #undef LIB_SPEC
 210 #define LIB_SPEC "%{!shared: \
 211    %{!pg:%{!pthread:%{!kthread:-lc} \
 212      %{kthread:-lpthread -lc}} \
 213      %{pthread:-lc_r}} \
 214    %{pg:%{!pthread:%{!kthread:-lc_p} \
 215      %{kthread:-lpthread_p -lc_p}} \
 216      %{pthread:-lc_r_p}}}"
 217
 218 /* Provide a LINK_SPEC appropriate for FreeBSD.  Here we provide support
 219    for the special GCC options -static and -shared, which allow us to
 220    link things in one of these three modes by applying the appropriate
 221    combinations of options at link-time. We like to support here for
 222    as many of the other GNU linker options as possible. But I don't
 223    have the time to search for those flags. I am sure how to add
 224    support for -soname shared_object_name. H.J.
 225
 226    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 227    -Wl,-V.
 228
 229    When the -shared link option is used a final link is not being
 230    done.  */
 231
 232 #undef  LINK_SPEC
 233 #define LINK_SPEC "-m elf_i386 \
 234   %{Wl,*:%*} \
 235   %{v:-V} \
 236   %{assert*} %{R*} %{rpath*} %{defsym*} \
 237   %{shared:-Bshareable %{h*} %{soname*}} \
 238     %{!shared: \
 239       %{!static: \
 240         %{rdynamic:-export-dynamic} \
 241         %{!dynamic-linker:-dynamic-linker /usr/libexec/ld-elf.so.1}} \
 242     %{static:-Bstatic}} \
 243   %{symbolic:-Bsymbolic}"
 244
 245 /* A C statement to output to the stdio stream FILE an assembler
 246    command to advance the location counter to a multiple of 1<<LOG
 247    bytes if it is within MAX_SKIP bytes.
 248
 249    This is used to align code labels according to Intel recommendations.  */
 250
 251 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 252 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP) \
 253   if ((LOG) != 0) {\
 254     if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG)); \
 255     else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP)); \
 256   }
 257 #endif