gcc/config/openbsd.h

   1 /* Base configuration file for all OpenBSD targets.
   2    Copyright (C) 1999, 2000, 2004, 2005, 2007 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC 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 3, or (at your option)
   9 any later version.
  10
  11 GCC 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 GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 /* Common OpenBSD configuration.
  21    All OpenBSD architectures include this file, which is intended as
  22    a repository for common defines.
  23
  24    Some defines are common to all architectures, a few of them are
  25    triggered by OBSD_* guards, so that we won't override architecture
  26    defaults by mistakes.
  27
  28    OBSD_HAS_CORRECT_SPECS:
  29       another mechanism provides correct specs already.
  30    OBSD_NO_DYNAMIC_LIBRARIES:
  31       no implementation of dynamic libraries.
  32    OBSD_OLD_GAS:
  33       older flavor of gas which needs help for PIC.
  34    OBSD_HAS_DECLARE_FUNCTION_NAME, OBSD_HAS_DECLARE_FUNCTION_SIZE,
  35    OBSD_HAS_DECLARE_OBJECT:
  36       PIC support, FUNCTION_NAME/FUNCTION_SIZE are independent, whereas
  37       the corresponding logic for OBJECTS is necessarily coupled.
  38
  39    There are also a few `default' defines such as ASM_WEAKEN_LABEL,
  40    intended as common ground for arch that don't provide
  41    anything suitable.  */
  42
  43 /* OPENBSD_NATIVE is defined only when gcc is configured as part of
  44    the OpenBSD source tree, specifically through Makefile.bsd-wrapper.
  45
  46    In such a case the include path can be trimmed as there is no
  47    distinction between system includes and gcc includes.  */
  48
  49 /* This configuration method, namely Makefile.bsd-wrapper and
  50    OPENBSD_NATIVE is NOT recommended for building cross-compilers.  */
  51
  52 #ifdef OPENBSD_NATIVE
  53
  54 /* The compiler is configured with ONLY the gcc/g++ standard headers.  */
  55 #undef INCLUDE_DEFAULTS
  56 #define INCLUDE_DEFAULTS                        \
  57   {                                             \
  58     { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1 },     \
  59     { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1 }, \
  60     { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1 }, \
  61     { STANDARD_INCLUDE_DIR, STANDARD_INCLUDE_COMPONENT, 0, 0 }, \
  62     { 0, 0, 0, 0 }                              \
  63   }
  64
  65 /* Under OpenBSD, the normal location of the various *crt*.o files is the
  66    /usr/lib directory.  */
  67 #undef STANDARD_STARTFILE_PREFIX
  68 #define STANDARD_STARTFILE_PREFIX       "/usr/local/lib/"
  69
  70 #endif
  71
  72 \f
  73 /* Controlling the compilation driver.  */
  74 /* TARGET_OS_CPP_BUILTINS() common to all OpenBSD targets.  */
  75 #define OPENBSD_OS_CPP_BUILTINS()               \
  76   do                                            \
  77     {                                           \
  78       builtin_define ("__OpenBSD__");           \
  79       builtin_define ("__unix__");              \
  80       builtin_define ("__ANSI_COMPAT");         \
  81       builtin_assert ("system=unix");           \
  82       builtin_assert ("system=bsd");            \
  83       builtin_assert ("system=OpenBSD");        \
  84     }                                           \
  85   while (0)
  86
  87 /* TARGET_OS_CPP_BUILTINS() common to all OpenBSD ELF targets.  */
  88 #define OPENBSD_OS_CPP_BUILTINS_ELF()           \
  89   do                                            \
  90     {                                           \
  91       OPENBSD_OS_CPP_BUILTINS();                \
  92       builtin_define ("__ELF__");               \
  93     }                                           \
  94 while (0)
  95
  96 /* TARGET_OS_CPP_BUILTINS() common to all LP64 OpenBSD targets.  */
  97 #define OPENBSD_OS_CPP_BUILTINS_LP64()          \
  98   do                                            \
  99     {                                           \
 100       builtin_define ("_LP64");                 \
 101       builtin_define ("__LP64__");              \
 102     }                                           \
 103   while (0)
 104
 105 /* CPP_SPEC appropriate for OpenBSD. We deal with -posix and -pthread.
 106    XXX the way threads are handled currently is not very satisfying,
 107    since all code must be compiled with -pthread to work.
 108    This two-stage defines makes it easy to pick that for targets that
 109    have subspecs.  */
 110 #ifdef CPP_CPU_SPEC
 111 #define OBSD_CPP_SPEC "%(cpp_cpu) %{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
 112 #else
 113 #define OBSD_CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
 114 #endif
 115
 116 #undef LIB_SPEC
 117 #define LIB_SPEC OBSD_LIB_SPEC
 118
 119 #ifndef OBSD_HAS_CORRECT_SPECS
 120
 121 #ifndef OBSD_NO_DYNAMIC_LIBRARIES
 122 #undef SWITCH_TAKES_ARG
 123 #define SWITCH_TAKES_ARG(CHAR) \
 124   (DEFAULT_SWITCH_TAKES_ARG (CHAR) \
 125    || (CHAR) == 'R')
 126 #endif
 127
 128 #undef CPP_SPEC
 129 #define CPP_SPEC OBSD_CPP_SPEC
 130
 131 #ifdef OBSD_OLD_GAS
 132 /* ASM_SPEC appropriate for OpenBSD.  For some architectures, OpenBSD
 133    still uses a special flavor of gas that needs to be told when generating
 134    pic code.  */
 135 #undef ASM_SPEC
 136 #define ASM_SPEC "%{fpic|fpie:-k} %{fPIC|fPIE:-k -K}"
 137 #endif
 138
 139 /* Since we use gas, stdin -> - is a good idea.  */
 140 #define AS_NEEDS_DASH_FOR_PIPED_INPUT
 141
 142 #undef LIB_SPEC
 143 #define LIB_SPEC OBSD_LIB_SPEC
 144
 145 #if defined(HAVE_LD_EH_FRAME_HDR)
 146 #define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
 147 #endif
 148
 149 #undef LIB_SPEC
 150 #define LIB_SPEC OBSD_LIB_SPEC
 151 #endif
 152
 153 \f
 154 /* Runtime target specification.  */
 155
 156 /* Miscellaneous parameters.  */
 157
 158 /* Controlling debugging info: dbx options.  */
 159
 160 /* Don't use the `xsTAG;' construct in DBX output; OpenBSD systems that
 161    use DBX don't support it.  */
 162 #define DBX_NO_XREFS
 163
 164 \f
 165 /* Support of shared libraries, mostly imported from svr4.h through netbsd.  */
 166 /* Two differences from svr4.h:
 167    - we use . - _func instead of a local label,
 168    - we put extra spaces in expressions such as
 169      .type _func , @function
 170      This is more readable for a human being and confuses c++filt less.  */
 171
 172 /* Assembler format: output and generation of labels.  */
 173
 174 /* Define the strings used for the .type and .size directives.
 175    These strings generally do not vary from one system running OpenBSD
 176    to another, but if a given system needs to use different pseudo-op
 177    names for these, they may be overridden in the arch specific file.  */
 178
 179 /* OpenBSD assembler is hacked to have .type & .size support even in a.out
 180    format object files.  Functions size are supported but not activated
 181    yet (look for GRACE_PERIOD_EXPIRED in gas/config/obj-aout.c).
 182    SET_ASM_OP is needed for attribute alias to work.  */
 183
 184 #undef TYPE_ASM_OP
 185 #undef SIZE_ASM_OP
 186 #undef SET_ASM_OP
 187 #undef GLOBAL_ASM_OP
 188
 189 #define TYPE_ASM_OP     "\t.type\t"
 190 #define SIZE_ASM_OP     "\t.size\t"
 191 #define SET_ASM_OP      "\t.set\t"
 192 #define GLOBAL_ASM_OP   "\t.globl\t"
 193
 194 /* The following macro defines the format used to output the second
 195    operand of the .type assembler directive.  */
 196 #undef TYPE_OPERAND_FMT
 197 #define TYPE_OPERAND_FMT        "@%s"
 198
 199 /* Provision if extra assembler code is needed to declare a function's result
 200    (taken from svr4, not needed yet actually).  */
 201 #ifndef ASM_DECLARE_RESULT
 202 #define ASM_DECLARE_RESULT(FILE, RESULT)
 203 #endif
 204
 205 /* These macros generate the special .type and .size directives which
 206    are used to set the corresponding fields of the linker symbol table
 207    entries under OpenBSD.  These macros also have to output the starting
 208    labels for the relevant functions/objects.  */
 209
 210 #ifndef OBSD_HAS_DECLARE_FUNCTION_NAME
 211 /* Extra assembler code needed to declare a function properly.
 212    Some assemblers may also need to also have something extra said
 213    about the function's return value.  We allow for that here.  */
 214 #undef ASM_DECLARE_FUNCTION_NAME
 215 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)                     \
 216   do {                                                                  \
 217     ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");                 \
 218     ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));                      \
 219     ASM_OUTPUT_FUNCTION_LABEL (FILE, NAME, DECL);                       \
 220   } while (0)
 221 #endif
 222
 223 #ifndef OBSD_HAS_DECLARE_FUNCTION_SIZE
 224 /* Declare the size of a function.  */
 225 #undef ASM_DECLARE_FUNCTION_SIZE
 226 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 227   do {                                                          \
 228     if (!flag_inhibit_size_directive)                           \
 229       ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                   \
 230   } while (0)
 231 #endif
 232
 233 #ifndef OBSD_HAS_DECLARE_OBJECT
 234 /* Extra assembler code needed to declare an object properly.  */
 235 #undef ASM_DECLARE_OBJECT_NAME
 236 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 237   do {                                                          \
 238       HOST_WIDE_INT size;                                       \
 239       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 240       size_directive_output = 0;                                \
 241       if (!flag_inhibit_size_directive                          \
 242           && (DECL) && DECL_SIZE (DECL))                        \
 243         {                                                       \
 244           size_directive_output = 1;                            \
 245           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 246           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 247         }                                                       \
 248       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 249   } while (0)
 250
 251 /* Output the size directive for a decl in rest_of_decl_compilation
 252    in the case where we did not do so before the initializer.
 253    Once we find the error_mark_node, we know that the value of
 254    size_directive_output was set by ASM_DECLARE_OBJECT_NAME
 255    when it was run for the same decl.  */
 256 #undef ASM_FINISH_DECLARE_OBJECT
 257 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 258 do {                                                                     \
 259      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 260      HOST_WIDE_INT size;                                                 \
 261      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 262          && ! AT_END && TOP_LEVEL                                        \
 263          && DECL_INITIAL (DECL) == error_mark_node                       \
 264          && !size_directive_output)                                      \
 265        {                                                                 \
 266          size_directive_output = 1;                                      \
 267          size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 268          ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);                   \
 269        }                                                                 \
 270    } while (0)
 271 #endif
 272
 273 \f
 274 /* Those are `generic' ways to weaken/globalize a label. We shouldn't need
 275    to override a processor specific definition. Hence, #ifndef ASM_*
 276    In case overriding turns out to be needed, one can always #undef ASM_*
 277    before including this file.  */
 278
 279 /* Tell the assembler that a symbol is weak.  */
 280 /* Note: netbsd arm32 assembler needs a .globl here. An override may
 281    be needed when/if we go for arm32 support.  */
 282 #ifndef ASM_WEAKEN_LABEL
 283 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 284   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 285        fputc ('\n', FILE); } while (0)
 286 #endif
 287 \f
 288 /* Storage layout.  */
 289
 290 \f
 291 /* bug work around: we don't want to support #pragma weak, but the current
 292    code layout needs HANDLE_PRAGMA_WEAK asserted for __attribute((weak)) to
 293    work.  On the other hand, we don't define HANDLE_PRAGMA_WEAK directly,
 294    as this depends on a few other details as well...  */
 295 #define HANDLE_SYSV_PRAGMA 1
 296
 297 /* Stack is explicitly denied execution rights on OpenBSD platforms.  */
 298 #define ENABLE_EXECUTE_STACK                                            \
 299 extern void __enable_execute_stack (void *);                            \
 300 void                                                                    \
 301 __enable_execute_stack (void *addr)                                     \
 302 {                                                                       \
 303   long size = getpagesize ();                                           \
 304   long mask = ~(size-1);                                                \
 305   char *page = (char *) (((long) addr) & mask);                         \
 306   char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
 307                                                                       \
 308   if (mprotect (page, end - page, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) \
 309     perror ("mprotect of trampoline code");                             \
 310 }
 311
 312 #include <sys/types.h>
 313 #include <sys/mman.h>