gcc/config/openbsd.h

   1 /* Base configuration file for all OpenBSD targets.
   2    Copyright (C) 1999, 2000, 2004, 2005, 2007, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC 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 3, or (at your option)
  10 any later version.
  11
  12 GCC 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 GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* Common OpenBSD configuration.
  22    All OpenBSD architectures include this file, which is intended as
  23    a repository for common defines.
  24
  25    Some defines are common to all architectures, a few of them are
  26    triggered by OBSD_* guards, so that we won't override architecture
  27    defaults by mistakes.
  28
  29    OBSD_HAS_CORRECT_SPECS:
  30       another mechanism provides correct specs already.
  31    OBSD_NO_DYNAMIC_LIBRARIES:
  32       no implementation of dynamic libraries.
  33    OBSD_OLD_GAS:
  34       older flavor of gas which needs help for PIC.
  35    OBSD_HAS_DECLARE_FUNCTION_NAME, OBSD_HAS_DECLARE_FUNCTION_SIZE,
  36    OBSD_HAS_DECLARE_OBJECT:
  37       PIC support, FUNCTION_NAME/FUNCTION_SIZE are independent, whereas
  38       the corresponding logic for OBJECTS is necessarily coupled.
  39
  40    There are also a few `default' defines such as ASM_WEAKEN_LABEL,
  41    intended as common ground for arch that don't provide
  42    anything suitable.  */
  43
  44 /* OPENBSD_NATIVE is defined only when gcc is configured as part of
  45    the OpenBSD source tree, specifically through Makefile.bsd-wrapper.
  46
  47    In such a case the include path can be trimmed as there is no
  48    distinction between system includes and gcc includes.  */
  49
  50 /* This configuration method, namely Makefile.bsd-wrapper and
  51    OPENBSD_NATIVE is NOT recommended for building cross-compilers.  */
  52
  53 #ifdef OPENBSD_NATIVE
  54
  55 /* The compiler is configured with ONLY the gcc/g++ standard headers.  */
  56 #undef INCLUDE_DEFAULTS
  57 #define INCLUDE_DEFAULTS                        \
  58   {                                             \
  59     { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1 },     \
  60     { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1 }, \
  61     { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1 }, \
  62     { STANDARD_INCLUDE_DIR, STANDARD_INCLUDE_COMPONENT, 0, 0 }, \
  63     { 0, 0, 0, 0 }                              \
  64   }
  65
  66 /* Under OpenBSD, the normal location of the various *crt*.o files is the
  67    /usr/lib directory.  */
  68 #undef STANDARD_STARTFILE_PREFIX
  69 #define STANDARD_STARTFILE_PREFIX       "/usr/local/lib/"
  70
  71 #endif
  72
  73 \f
  74 /* Controlling the compilation driver.  */
  75 /* TARGET_OS_CPP_BUILTINS() common to all OpenBSD targets.  */
  76 #define OPENBSD_OS_CPP_BUILTINS()               \
  77   do                                            \
  78     {                                           \
  79       builtin_define ("__OpenBSD__");           \
  80       builtin_define ("__unix__");              \
  81       builtin_define ("__ANSI_COMPAT");         \
  82       builtin_assert ("system=unix");           \
  83       builtin_assert ("system=bsd");            \
  84       builtin_assert ("system=OpenBSD");        \
  85     }                                           \
  86   while (0)
  87
  88 /* TARGET_OS_CPP_BUILTINS() common to all OpenBSD ELF targets.  */
  89 #define OPENBSD_OS_CPP_BUILTINS_ELF()           \
  90   do                                            \
  91     {                                           \
  92       OPENBSD_OS_CPP_BUILTINS();                \
  93       builtin_define ("__ELF__");               \
  94     }                                           \
  95 while (0)
  96
  97 /* TARGET_OS_CPP_BUILTINS() common to all LP64 OpenBSD targets.  */
  98 #define OPENBSD_OS_CPP_BUILTINS_LP64()          \
  99   do                                            \
 100     {                                           \
 101       builtin_define ("_LP64");                 \
 102       builtin_define ("__LP64__");              \
 103     }                                           \
 104   while (0)
 105
 106 /* CPP_SPEC appropriate for OpenBSD. We deal with -posix and -pthread.
 107    XXX the way threads are handled currently is not very satisfying,
 108    since all code must be compiled with -pthread to work.
 109    This two-stage defines makes it easy to pick that for targets that
 110    have subspecs.  */
 111 #ifdef CPP_CPU_SPEC
 112 #define OBSD_CPP_SPEC "%(cpp_cpu) %{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
 113 #else
 114 #define OBSD_CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
 115 #endif
 116
 117 #undef LIB_SPEC
 118 #define LIB_SPEC OBSD_LIB_SPEC
 119
 120 #ifndef OBSD_HAS_CORRECT_SPECS
 121
 122 #undef CPP_SPEC
 123 #define CPP_SPEC OBSD_CPP_SPEC
 124
 125 #ifdef OBSD_OLD_GAS
 126 /* ASM_SPEC appropriate for OpenBSD.  For some architectures, OpenBSD
 127    still uses a special flavor of gas that needs to be told when generating
 128    pic code.  */
 129 #undef ASM_SPEC
 130 #define ASM_SPEC "%{fpic|fpie:-k} %{fPIC|fPIE:-k -K}"
 131 #endif
 132
 133 /* Since we use gas, stdin -> - is a good idea.  */
 134 #define AS_NEEDS_DASH_FOR_PIPED_INPUT
 135
 136 #undef LIB_SPEC
 137 #define LIB_SPEC OBSD_LIB_SPEC
 138
 139 #if defined(HAVE_LD_EH_FRAME_HDR)
 140 #define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
 141 #endif
 142
 143 #undef LIB_SPEC
 144 #define LIB_SPEC OBSD_LIB_SPEC
 145 #endif
 146
 147 #define TARGET_POSIX_IO
 148 \f
 149 /* Runtime target specification.  */
 150
 151 /* Miscellaneous parameters.  */
 152
 153 /* Controlling debugging info: dbx options.  */
 154
 155 /* Don't use the `xsTAG;' construct in DBX output; OpenBSD systems that
 156    use DBX don't support it.  */
 157 #define DBX_NO_XREFS
 158
 159 \f
 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_FUNCTION_LABEL (FILE, NAME, DECL);                       \
 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 /* Stack is explicitly denied execution rights on OpenBSD platforms.  */
 285 #define ENABLE_EXECUTE_STACK                                            \
 286 extern void __enable_execute_stack (void *);                            \
 287 void                                                                    \
 288 __enable_execute_stack (void *addr)                                     \
 289 {                                                                       \
 290   long size = getpagesize ();                                           \
 291   long mask = ~(size-1);                                                \
 292   char *page = (char *) (((long) addr) & mask);                         \
 293   char *end  = (char *) ((((long) (addr + TRAMPOLINE_SIZE)) & mask) + size); \
 294                                                                       \
 295   if (mprotect (page, end - page, PROT_READ | PROT_WRITE | PROT_EXEC) < 0) \
 296     perror ("mprotect of trampoline code");                             \
 297 }
 298
 299 #include <sys/types.h>
 300 #include <sys/mman.h>