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   1 /* Definitions for Intel 386 running system V, using gas.
   2    Copyright (C) 1992 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #include "i386/gas.h"
  22
  23 /* Add stuff that normally comes from i386/sysv3.h */
  24
  25 /* longjmp may fail to restore the registers if called from the same
  26    function that called setjmp.  To compensate, the compiler avoids
  27    putting variables in registers in functions that use both setjmp
  28    and longjmp.  */
  29
  30 #define NON_SAVING_SETJMP \
  31   (current_function_calls_setjmp && current_function_calls_longjmp)
  32
  33 /* longjmp may fail to restore the stack pointer if the saved frame
  34    pointer is the same as the caller's frame pointer.  Requiring a frame
  35    pointer in any function that calls setjmp or longjmp avoids this
  36    problem, unless setjmp and longjmp are called from the same function.
  37    Since a frame pointer will be required in such a function, it is OK
  38    that the stack pointer is not restored.  */
  39
  40 #undef FRAME_POINTER_REQUIRED
  41 #define FRAME_POINTER_REQUIRED \
  42   (current_function_calls_setjmp || current_function_calls_longjmp)
  43
  44 /* Modify ASM_OUTPUT_LOCAL slightly to test -msvr3-shlib, adapted to gas  */
  45 #undef ASM_OUTPUT_LOCAL
  46 #define ASM_OUTPUT_LOCAL(FILE, NAME, SIZE, ROUNDED)     \
  47   do {                                                  \
  48     int align = exact_log2 (ROUNDED);                   \
  49     if (align > 2) align = 2;                           \
  50     if (TARGET_SVR3_SHLIB)                              \
  51       {                                                 \
  52         data_section ();                                \
  53         ASM_OUTPUT_ALIGN ((FILE), align == -1 ? 2 : align); \
  54         ASM_OUTPUT_LABEL ((FILE), (NAME));              \
  55         fprintf ((FILE), "\t.set .,.+%u\n", (ROUNDED)); \
  56       }                                                 \
  57     else                                                \
  58       {                                                 \
  59         fputs (".lcomm ", (FILE));                      \
  60         assemble_name ((FILE), (NAME));                 \
  61         fprintf ((FILE), ",%u\n", (ROUNDED));           \
  62       }                                                 \
  63   } while (0)
  64
  65 /* Add stuff that normally comes from i386/sysv3.h via svr3.h */
  66
  67 /* Define the actual types of some ANSI-mandated types.  These
  68    definitions should work for most SVR3 systems.  */
  69
  70 #undef SIZE_TYPE
  71 #define SIZE_TYPE "unsigned int"
  72
  73 #undef PTRDIFF_TYPE
  74 #define PTRDIFF_TYPE "int"
  75
  76 #undef WCHAR_TYPE
  77 #define WCHAR_TYPE "long int"
  78
  79 #undef WCHAR_TYPE_SIZE
  80 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  81 \f
  82 /* ??? This stuff is copied from config/svr3.h.  In the future,
  83    this file should be rewritten to include config/svr3.h
  84    and override what isn't right.  */
  85
  86 /* Support const sections and the ctors and dtors sections for g++.
  87    Note that there appears to be two different ways to support const
  88    sections at the moment.  You can either #define the symbol
  89    READONLY_DATA_SECTION (giving it some code which switches to the
  90    readonly data section) or else you can #define the symbols
  91    EXTRA_SECTIONS, EXTRA_SECTION_FUNCTIONS, SELECT_SECTION, and
  92    SELECT_RTX_SECTION.  We do both here just to be on the safe side.
  93    However, use of the const section is turned off by default
  94    unless the specific tm.h file turns it on by defining
  95    USE_CONST_SECTION as 1.  */
  96
  97 /* Define a few machine-specific details of the implementation of
  98    constructors.
  99
 100    The __CTORS_LIST__ goes in the .init section.  Define CTOR_LIST_BEGIN
 101    and CTOR_LIST_END to contribute to the .init section an instruction to
 102    push a word containing 0 (or some equivalent of that).
 103
 104    Define ASM_OUTPUT_CONSTRUCTOR to push the address of the constructor.  */
 105
 106 #define USE_CONST_SECTION       0
 107
 108 #define INIT_SECTION_ASM_OP     ".section\t.init"
 109 #define FINI_SECTION_ASM_OP     ".section .fini,\"x\""
 110 #define CONST_SECTION_ASM_OP    ".section\t.rodata, \"x\""
 111 #define CTORS_SECTION_ASM_OP    INIT_SECTION_ASM_OP
 112 #define DTORS_SECTION_ASM_OP    FINI_SECTION_ASM_OP
 113
 114 /* CTOR_LIST_BEGIN and CTOR_LIST_END are machine-dependent
 115    because they push on the stack.  */
 116
 117 #ifdef STACK_GROWS_DOWNWARD
 118
 119 /* Constructor list on stack is in reverse order.  Go to the end of the
 120    list and go backwards to call constructors in the right order.  */
 121 #define DO_GLOBAL_CTORS_BODY                                    \
 122 do {                                                            \
 123   func_ptr *p, *beg = alloca (0);                               \
 124   for (p = beg; *p; p++)                                        \
 125     ;                                                           \
 126   while (p != beg)                                              \
 127     (*--p) ();                                                  \
 128 } while (0)
 129
 130 #else
 131
 132 /* Constructor list on stack is in correct order.  Just call them.  */
 133 #define DO_GLOBAL_CTORS_BODY                                    \
 134 do {                                                            \
 135   func_ptr *p, *beg = alloca (0);                               \
 136   for (p = beg; *p; )                                           \
 137     (*p++) ();                                                  \
 138 } while (0)
 139
 140 #endif /* STACK_GROWS_DOWNWARD */
 141
 142 /* Add extra sections .init and .fini, in addition to .bss from att386.h. */
 143
 144 #undef EXTRA_SECTIONS
 145 #define EXTRA_SECTIONS in_const, in_bss, in_init, in_fini
 146
 147 #undef EXTRA_SECTION_FUNCTIONS
 148 #define EXTRA_SECTION_FUNCTIONS                                 \
 149   CONST_SECTION_FUNCTION                                        \
 150   BSS_SECTION_FUNCTION                                          \
 151   INIT_SECTION_FUNCTION                                         \
 152   FINI_SECTION_FUNCTION
 153
 154 #define BSS_SECTION_FUNCTION                                    \
 155 void                                                            \
 156 bss_section ()                                                  \
 157 {                                                               \
 158   if (in_section != in_bss)                                     \
 159     {                                                           \
 160       fprintf (asm_out_file, "\t%s\n", BSS_SECTION_ASM_OP);     \
 161       in_section = in_bss;                                      \
 162     }                                                           \
 163 }
 164
 165 #define INIT_SECTION_FUNCTION                                   \
 166 void                                                            \
 167 init_section ()                                                 \
 168 {                                                               \
 169   if (in_section != in_init)                                    \
 170     {                                                           \
 171       fprintf (asm_out_file, "\t%s\n", INIT_SECTION_ASM_OP);    \
 172       in_section = in_init;                                     \
 173     }                                                           \
 174 }
 175
 176 #define FINI_SECTION_FUNCTION                                   \
 177 void                                                            \
 178 fini_section ()                                                 \
 179 {                                                               \
 180   if (in_section != in_fini)                                    \
 181     {                                                           \
 182       fprintf (asm_out_file, "\t%s\n", FINI_SECTION_ASM_OP);    \
 183       in_section = in_fini;                                     \
 184     }                                                           \
 185 }
 186
 187 #define READONLY_DATA_SECTION() const_section ()
 188
 189 #define CONST_SECTION_FUNCTION                                          \
 190 void                                                                    \
 191 const_section ()                                                        \
 192 {                                                                       \
 193   extern void text_section();                                           \
 194   if (!USE_CONST_SECTION)                                               \
 195     text_section();                                                     \
 196   else if (in_section != in_const)                                      \
 197     {                                                                   \
 198       fprintf (asm_out_file, "%s\n", CONST_SECTION_ASM_OP);             \
 199       in_section = in_const;                                            \
 200     }                                                                   \
 201 }
 202
 203 /* The ctors and dtors sections are not normally put into use
 204    by EXTRA_SECTIONS and EXTRA_SECTION_FUNCTIONS as defined in svr3.h,
 205    but it can't hurt to define these macros for whatever systems use them.  */
 206 #define CTORS_SECTION_FUNCTION                                          \
 207 void                                                                    \
 208 ctors_section ()                                                        \
 209 {                                                                       \
 210   if (in_section != in_ctors)                                           \
 211     {                                                                   \
 212       fprintf (asm_out_file, "%s\n", CTORS_SECTION_ASM_OP);             \
 213       in_section = in_ctors;                                            \
 214     }                                                                   \
 215 }
 216
 217 #define DTORS_SECTION_FUNCTION                                          \
 218 void                                                                    \
 219 dtors_section ()                                                        \
 220 {                                                                       \
 221   if (in_section != in_dtors)                                           \
 222     {                                                                   \
 223       fprintf (asm_out_file, "%s\n", DTORS_SECTION_ASM_OP);             \
 224       in_section = in_dtors;                                            \
 225     }                                                                   \
 226 }
 227
 228 /* This is machine-dependent
 229    because it needs to push something on the stack.  */
 230 #undef ASM_OUTPUT_CONSTRUCTOR
 231
 232 /* A C statement (sans semicolon) to output an element in the table of
 233    global destructors.  */
 234 #define ASM_OUTPUT_DESTRUCTOR(FILE,NAME)                                \
 235   do {                                                                  \
 236     fini_section ();                                            \
 237     fprintf (FILE, "%s\t ", ASM_LONG);                                  \
 238     assemble_name (FILE, NAME);                                         \
 239     fprintf (FILE, "\n");                                               \
 240   } while (0)
 241
 242 /* A C statement or statements to switch to the appropriate
 243    section for output of DECL.  DECL is either a `VAR_DECL' node
 244    or a constant of some sort.  RELOC indicates whether forming
 245    the initial value of DECL requires link-time relocations.  */
 246
 247 #define SELECT_SECTION(DECL,RELOC)                                      \
 248 {                                                                       \
 249   if (TREE_CODE (DECL) == STRING_CST)                                   \
 250     {                                                                   \
 251       if (! flag_writable_strings)                                      \
 252         const_section ();                                               \
 253       else                                                              \
 254         data_section ();                                                \
 255     }                                                                   \
 256   else if (TREE_CODE (DECL) == VAR_DECL)                                \
 257     {                                                                   \
 258       if ((0 && RELOC)  /* should be (flag_pic && RELOC) */             \
 259           || !TREE_READONLY (DECL) || TREE_SIDE_EFFECTS (DECL)          \
 260           || !DECL_INITIAL (DECL)                                       \
 261           || (DECL_INITIAL (DECL) != error_mark_node                    \
 262               && !TREE_CONSTANT (DECL_INITIAL (DECL))))                 \
 263         data_section ();                                                \
 264       else                                                              \
 265         const_section ();                                               \
 266     }                                                                   \
 267   else                                                                  \
 268     const_section ();                                                   \
 269 }
 270
 271 /* A C statement or statements to switch to the appropriate
 272    section for output of RTX in mode MODE.  RTX is some kind
 273    of constant in RTL.  The argument MODE is redundant except
 274    in the case of a `const_int' rtx.  Currently, these always
 275    go into the const section.  */
 276
 277 #define SELECT_RTX_SECTION(MODE,RTX) const_section()
 278 \f
 279 /* This is copied from i386/sysv3.h.  */
 280
 281 /* Define a few machine-specific details of the implementation of
 282    constructors.
 283
 284    The __CTORS_LIST__ goes in the .init section.  Define CTOR_LIST_BEGIN
 285    and CTOR_LIST_END to contribute to the .init section an instruction to
 286    push a word containing 0 (or some equivalent of that).
 287
 288    ASM_OUTPUT_CONSTRUCTOR should be defined to push the address of the
 289    constructor.  */
 290
 291 #undef INIT_SECTION_ASM_OP
 292 #define INIT_SECTION_ASM_OP     ".section .init,\"x\""
 293
 294 #define CTOR_LIST_BEGIN                         \
 295   asm (INIT_SECTION_ASM_OP);                    \
 296   asm ("pushl $0")
 297 #define CTOR_LIST_END CTOR_LIST_BEGIN
 298
 299 #define ASM_OUTPUT_CONSTRUCTOR(FILE,NAME)       \
 300   do {                                          \
 301     init_section ();                            \
 302     fprintf (FILE, "\tpushl $");                \
 303     assemble_name (FILE, NAME);                 \
 304     fprintf (FILE, "\n");                       \
 305   } while (0)