gcc/config/openbsd.h

   1 /* Base configuration file for all OpenBSD targets.
   2    Copyright (C) 1999-2018 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     { NATIVE_SYSTEM_HEADER_DIR, NATIVE_SYSTEM_HEADER_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 #undef CPP_SPEC
 122 #define CPP_SPEC OBSD_CPP_SPEC
 123
 124 #ifdef OBSD_OLD_GAS
 125 /* ASM_SPEC appropriate for OpenBSD.  For some architectures, OpenBSD
 126    still uses a special flavor of gas that needs to be told when generating
 127    pic code.  */
 128 #undef ASM_SPEC
 129 #define ASM_SPEC "%{" FPIE1_OR_FPIC1_SPEC ":-k} %{" FPIE2_OR_FPIC2_SPEC ":-k -K}"
 130 #endif
 131
 132 /* Since we use gas, stdin -> - is a good idea.  */
 133 #define AS_NEEDS_DASH_FOR_PIPED_INPUT
 134
 135 #undef LIB_SPEC
 136 #define LIB_SPEC OBSD_LIB_SPEC
 137
 138 #if defined(HAVE_LD_EH_FRAME_HDR)
 139 #define LINK_EH_SPEC "%{!static|static-pie:--eh-frame-hdr} "
 140 #endif
 141
 142 #undef LIB_SPEC
 143 #define LIB_SPEC OBSD_LIB_SPEC
 144 #endif
 145
 146 #define TARGET_POSIX_IO
 147
 148 /* All new versions of OpenBSD have C99 functions.  We redefine this hook
 149    so the version from elfos.h header won't be used.  */
 150 #undef TARGET_LIBC_HAS_FUNCTION
 151 #define TARGET_LIBC_HAS_FUNCTION default_libc_has_function
 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 /* - we use . - _func instead of a local label,
 166    - we put extra spaces in expressions such as
 167      .type _func , @function
 168      This is more readable for a human being and confuses c++filt less.  */
 169
 170 /* Assembler format: output and generation of labels.  */
 171
 172 /* Define the strings used for the .type and .size directives.
 173    These strings generally do not vary from one system running OpenBSD
 174    to another, but if a given system needs to use different pseudo-op
 175    names for these, they may be overridden in the arch specific file.  */
 176
 177 /* OpenBSD assembler is hacked to have .type & .size support even in a.out
 178    format object files.  Functions size are supported but not activated
 179    yet (look for GRACE_PERIOD_EXPIRED in gas/config/obj-aout.c).
 180    SET_ASM_OP is needed for attribute alias to work.  */
 181
 182 #undef TYPE_ASM_OP
 183 #undef SIZE_ASM_OP
 184 #undef SET_ASM_OP
 185 #undef GLOBAL_ASM_OP
 186
 187 #define TYPE_ASM_OP     "\t.type\t"
 188 #define SIZE_ASM_OP     "\t.size\t"
 189 #define SET_ASM_OP      "\t.set\t"
 190 #define GLOBAL_ASM_OP   "\t.globl\t"
 191
 192 /* The following macro defines the format used to output the second
 193    operand of the .type assembler directive.  */
 194 #undef TYPE_OPERAND_FMT
 195 #define TYPE_OPERAND_FMT        "@%s"
 196
 197 /* Provision if extra assembler code is needed to declare a function's result
 198    (taken from svr4, not needed yet actually).  */
 199 #ifndef ASM_DECLARE_RESULT
 200 #define ASM_DECLARE_RESULT(FILE, RESULT)
 201 #endif
 202
 203 /* These macros generate the special .type and .size directives which
 204    are used to set the corresponding fields of the linker symbol table
 205    entries under OpenBSD.  These macros also have to output the starting
 206    labels for the relevant functions/objects.  */
 207
 208 #ifndef OBSD_HAS_DECLARE_FUNCTION_NAME
 209 /* Extra assembler code needed to declare a function properly.
 210    Some assemblers may also need to also have something extra said
 211    about the function's return value.  We allow for that here.  */
 212 #undef ASM_DECLARE_FUNCTION_NAME
 213 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)                     \
 214   do {                                                                  \
 215     ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");                 \
 216     ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));                      \
 217     ASM_OUTPUT_FUNCTION_LABEL (FILE, NAME, DECL);                       \
 218   } while (0)
 219 #endif
 220
 221 #ifndef OBSD_HAS_DECLARE_FUNCTION_SIZE
 222 /* Declare the size of a function.  */
 223 #undef ASM_DECLARE_FUNCTION_SIZE
 224 #define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)            \
 225   do {                                                          \
 226     if (!flag_inhibit_size_directive)                           \
 227       ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);                   \
 228   } while (0)
 229 #endif
 230
 231 #ifndef OBSD_HAS_DECLARE_OBJECT
 232 /* Extra assembler code needed to declare an object properly.  */
 233 #undef ASM_DECLARE_OBJECT_NAME
 234 #define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)               \
 235   do {                                                          \
 236       HOST_WIDE_INT size;                                       \
 237       ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");         \
 238       size_directive_output = 0;                                \
 239       if (!flag_inhibit_size_directive                          \
 240           && (DECL) && DECL_SIZE (DECL))                        \
 241         {                                                       \
 242           size_directive_output = 1;                            \
 243           size = int_size_in_bytes (TREE_TYPE (DECL));          \
 244           ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);         \
 245         }                                                       \
 246       ASM_OUTPUT_LABEL (FILE, NAME);                            \
 247   } while (0)
 248
 249 /* Output the size directive for a decl in rest_of_decl_compilation
 250    in the case where we did not do so before the initializer.
 251    Once we find the error_mark_node, we know that the value of
 252    size_directive_output was set by ASM_DECLARE_OBJECT_NAME
 253    when it was run for the same decl.  */
 254 #undef ASM_FINISH_DECLARE_OBJECT
 255 #define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)         \
 256 do {                                                                     \
 257      const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);             \
 258      HOST_WIDE_INT size;                                                 \
 259      if (!flag_inhibit_size_directive && DECL_SIZE (DECL)                \
 260          && ! AT_END && TOP_LEVEL                                        \
 261          && DECL_INITIAL (DECL) == error_mark_node                       \
 262          && !size_directive_output)                                      \
 263        {                                                                 \
 264          size_directive_output = 1;                                      \
 265          size = int_size_in_bytes (TREE_TYPE (DECL));                    \
 266          ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);                   \
 267        }                                                                 \
 268    } while (0)
 269 #endif
 270
 271 \f
 272 /* Those are `generic' ways to weaken/globalize a label. We shouldn't need
 273    to override a processor specific definition. Hence, #ifndef ASM_*
 274    In case overriding turns out to be needed, one can always #undef ASM_*
 275    before including this file.  */
 276
 277 /* Tell the assembler that a symbol is weak.  */
 278 /* Note: netbsd arm32 assembler needs a .globl here. An override may
 279    be needed when/if we go for arm32 support.  */
 280 #ifndef ASM_WEAKEN_LABEL
 281 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 282   do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
 283        fputc ('\n', FILE); } while (0)
 284 #endif
 285 \f
 286 /* Storage layout.  */
 287
 288 \f
 289 #define HAVE_ENABLE_EXECUTE_STACK