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 /* CPP_SPEC appropriate for OpenBSD. We deal with -posix and -pthread.
  88    XXX the way threads are handled currently is not very satisfying,
  89    since all code must be compiled with -pthread to work.
  90    This two-stage defines makes it easy to pick that for targets that
  91    have subspecs.  */
  92 #ifdef CPP_CPU_SPEC
  93 #define OBSD_CPP_SPEC "%(cpp_cpu) %{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
  94 #else
  95 #define OBSD_CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
  96 #endif
  97
  98 /* LIB_SPEC appropriate for OpenBSD.  */
  99 #ifdef HAS_LIBC_R
 100 /*   -lc(_r)?(_p)?, select _r for threads, and _p for p or pg.  */
 101 # define OBSD_LIB_SPEC "%{!shared:-lc%{pthread:_r}%{p:_p}%{!p:%{pg:_p}}}"
 102 #else
 103 /* Include -lpthread if -pthread is specified on the command line. */
 104 # define OBSD_LIB_SPEC "%{!shared:%{pthread:-lpthread%{p:_p}%{!p:%{pg:_p}}}} %{!shared:-lc%{p:_p}%{!p:%{pg:_p}}}"
 105 #endif
 106
 107
 108 #ifndef OBSD_HAS_CORRECT_SPECS
 109
 110 #ifndef OBSD_NO_DYNAMIC_LIBRARIES
 111 #undef SWITCH_TAKES_ARG
 112 #define SWITCH_TAKES_ARG(CHAR) \
 113   (DEFAULT_SWITCH_TAKES_ARG (CHAR) \
 114    || (CHAR) == 'R')
 115 #endif
 116
 117 #undef CPP_SPEC
 118 #define CPP_SPEC OBSD_CPP_SPEC
 119
 120 #ifdef OBSD_OLD_GAS
 121 /* ASM_SPEC appropriate for OpenBSD.  For some architectures, OpenBSD
 122    still uses a special flavor of gas that needs to be told when generating
 123    pic code.  */
 124 #undef ASM_SPEC
 125 #define ASM_SPEC "%{fpic|fpie:-k} %{fPIC|fPIE:-k -K}"
 126 #endif
 127
 128 /* Since we use gas, stdin -> - is a good idea.  */
 129 #define AS_NEEDS_DASH_FOR_PIPED_INPUT
 130
 131 /* LINK_SPEC appropriate for OpenBSD.  Support for GCC options
 132    -static, -assert, and -nostdlib.  */
 133 #undef LINK_SPEC
 134 #ifdef OBSD_NO_DYNAMIC_LIBRARIES
 135 #define LINK_SPEC \
 136   "%{g:%{!nostdlib:-L/usr/lib/debug}} %{!nostdlib:%{!r*:%{!e*:-e start}}} -dc -dp %{assert*}"
 137 #else
 138 #define LINK_SPEC \
 139   "%{g:%{!nostdlib:-L/usr/lib/debug}} %{!shared:%{!nostdlib:%{!r*:%{!e*:-e start}}}} %{shared:-Bshareable -x} -dc -dp %{R*} %{static:-Bstatic} %{assert*}"
 140 #endif
 141
 142 #undef LIB_SPEC
 143 #define LIB_SPEC OBSD_LIB_SPEC
 144 #endif
 145
 146 \f
 147 /* Runtime target specification.  */
 148
 149 /* Miscellaneous parameters.  */
 150
 151 /* Controlling debugging info: dbx options.  */
 152
 153 /* Don't use the `xsTAG;' construct in DBX output; OpenBSD systems that
 154    use DBX don't support it.  */
 155 #define DBX_NO_XREFS
 156
 157 \f
 158 /* Support of shared libraries, mostly imported from svr4.h through netbsd.  */
 159 /* Two differences from svr4.h:
 160    - we use . - _func instead of a local label,
 161    - we put extra spaces in expressions such as
 162      .type _func , @function
 163      This is more readable for a human being and confuses c++filt less.  */
 164
 165 /* Assembler format: output and generation of labels.  */
 166
 167 /* Define the strings used for the .type and .size directives.
 168    These strings generally do not vary from one system running OpenBSD
 169    to another, but if a given system needs to use different pseudo-op
 170    names for these, they may be overridden in the arch specific file.  */
 171
 172 /* OpenBSD assembler is hacked to have .type & .size support even in a.out
 173    format object files.  Functions size are supported but not activated
 174    yet (look for GRACE_PERIOD_EXPIRED in gas/config/obj-aout.c).
 175    SET_ASM_OP is needed for attribute alias to work.  */
 176
 177 #undef TYPE_ASM_OP
 178 #undef SIZE_ASM_OP
 179 #undef SET_ASM_OP
 180 #undef GLOBAL_ASM_OP
 181
 182 #define TYPE_ASM_OP     "\t.type\t"
 183 #define SIZE_ASM_OP     "\t.size\t"
 184 #define SET_ASM_OP      "\t.set\t"
 185 #define GLOBAL_ASM_OP   "\t.globl\t"
 186
 187 /* The following macro defines the format used to output the second
 188    operand of the .type assembler directive.  */
 189 #undef TYPE_OPERAND_FMT
 190 #define TYPE_OPERAND_FMT        "@%s"
 191
 192 /* Provision if extra assembler code is needed to declare a function's result
 193    (taken from svr4, not needed yet actually).  */
 194 #ifndef ASM_DECLARE_RESULT
 195 #define ASM_DECLARE_RESULT(FILE, RESULT)
 196 #endif
 197
 198 /* These macros generate the special .type and .size directives which
 199    are used to set the corresponding fields of the linker symbol table
 200    entries under OpenBSD.  These macros also have to output the starting
 201    labels for the relevant functions/objects.  */
 202
 203 #ifndef OBSD_HAS_DECLARE_FUNCTION_NAME
 204 /* Extra assembler code needed to declare a function properly.
 205    Some assemblers may also need to also have something extra said
 206    about the function's return value.  We allow for that here.  */
 207 #undef ASM_DECLARE_FUNCTION_NAME
 208 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)                     \
 209   do {                                                                  \
 210     ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");                 \
 211     ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));                      \
 212     ASM_OUTPUT_LABEL(FILE, NAME);                                       \
 213   } while (0)
 214 #endif
 215
 216 #ifndef OBSD_HAS_DECLARE_FUNCTION_SIZE
 217 /* Declare the size of a function.  */
 218 #undef ASM_DECLARE_FUNCTION_SIZE
 219 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 220   do {                                                          \
 221     if (!flag_inhibit_size_directive)                           \
 222       ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                   \
 223   } while (0)
 224 #endif
 225
 226 #ifndef OBSD_HAS_DECLARE_OBJECT
 227 /* Extra assembler code needed to declare an object properly.  */
 228 #undef ASM_DECLARE_OBJECT_NAME
 229 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 230   do {                                                          \
 231       HOST_WIDE_INT size;                                       \
 232       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 233       size_directive_output = 0;                                \
 234       if (!flag_inhibit_size_directive                          \
 235           && (DECL) && DECL_SIZE (DECL))                        \
 236         {                                                       \
 237           size_directive_output = 1;                            \
 238           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 239           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 240         }                                                       \
 241       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 242   } while (0)
 243
 244 /* Output the size directive for a decl in rest_of_decl_compilation
 245    in the case where we did not do so before the initializer.
 246    Once we find the error_mark_node, we know that the value of
 247    size_directive_output was set by ASM_DECLARE_OBJECT_NAME
 248    when it was run for the same decl.  */
 249 #undef ASM_FINISH_DECLARE_OBJECT
 250 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 251 do {                                                                     \
 252      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 253      HOST_WIDE_INT size;                                                 \
 254      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 255          && ! AT_END && TOP_LEVEL                                        \
 256          && DECL_INITIAL (DECL) == error_mark_node                       \
 257          && !size_directive_output)                                      \
 258        {                                                                 \
 259          size_directive_output = 1;                                      \
 260          size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 261          ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);                   \
 262        }                                                                 \
 263    } while (0)
 264 #endif
 265
 266 \f
 267 /* Those are `generic' ways to weaken/globalize a label. We shouldn't need
 268    to override a processor specific definition. Hence, #ifndef ASM_*
 269    In case overriding turns out to be needed, one can always #undef ASM_*
 270    before including this file.  */
 271
 272 /* Tell the assembler that a symbol is weak.  */
 273 /* Note: netbsd arm32 assembler needs a .globl here. An override may
 274    be needed when/if we go for arm32 support.  */
 275 #ifndef ASM_WEAKEN_LABEL
 276 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 277   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 278        fputc ('\n', FILE); } while (0)
 279 #endif
 280 \f
 281 /* Storage layout.  */
 282
 283 \f
 284 /* Otherwise, since we support weak, gthr.h erroneously tries to use
 285    #pragma weak.  */
 286 #define GTHREAD_USE_WEAK 0
 287
 288 /* bug work around: we don't want to support #pragma weak, but the current
 289    code layout needs HANDLE_PRAGMA_WEAK asserted for __attribute((weak)) to
 290    work.  On the other hand, we don't define HANDLE_PRAGMA_WEAK directly,
 291    as this depends on a few other details as well...  */
 292 #define HANDLE_SYSV_PRAGMA 1
 293
 294 /* Stack is explicitly denied execution rights on OpenBSD platforms.  */
 295 #define ENABLE_EXECUTE_STACK                                            \
 296 extern void __enable_execute_stack (void *);                            \
 297 void                                                                    \
 298 __enable_execute_stack (void *addr)                                     \
 299 {                                                                       \
 300   long size = getpagesize ();                                           \
 301   long mask = ~(size-1);                                                \
 302   char *page = (char *) (((long) addr) & mask);                         \
 303   char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
 304                                                                       \
 305   if (mprotect (page, end - page, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) \
 306     perror ("mprotect of trampoline code");                             \
 307 }
 308
 309 #include <sys/types.h>
 310 #include <sys/mman.h>