gcc/config/openbsd.h

/* Base configuration file for all OpenBSD targets.
   Copyright (C) 1999-2020 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* Common OpenBSD configuration. 
   All OpenBSD architectures include this file, which is intended as
   a repository for common defines. 

   Some defines are common to all architectures, a few of them are
   triggered by OBSD_* guards, so that we won't override architecture
   defaults by mistakes.

   OBSD_HAS_CORRECT_SPECS: 
      another mechanism provides correct specs already.
   OBSD_NO_DYNAMIC_LIBRARIES: 
      no implementation of dynamic libraries.
   OBSD_OLD_GAS: 
      older flavor of gas which needs help for PIC.
   OBSD_HAS_DECLARE_FUNCTION_NAME, OBSD_HAS_DECLARE_FUNCTION_SIZE,
   OBSD_HAS_DECLARE_OBJECT: 
      PIC support, FUNCTION_NAME/FUNCTION_SIZE are independent, whereas
      the corresponding logic for OBJECTS is necessarily coupled.

   There are also a few `default' defines such as ASM_WEAKEN_LABEL,
   intended as common ground for arch that don't provide 
   anything suitable.  */

/* OPENBSD_NATIVE is defined only when gcc is configured as part of
   the OpenBSD source tree, specifically through Makefile.bsd-wrapper.

   In such a case the include path can be trimmed as there is no
   distinction between system includes and gcc includes.  */

/* This configuration method, namely Makefile.bsd-wrapper and
   OPENBSD_NATIVE is NOT recommended for building cross-compilers.  */

#ifdef OPENBSD_NATIVE

/* The compiler is configured with ONLY the gcc/g++ standard headers.  */
#undef INCLUDE_DEFAULTS
#define INCLUDE_DEFAULTS			\
  {						\
    { GPLUSPLUS_INCLUDE_DIR, "G++", 1, 1 },	\
    { GPLUSPLUS_TOOL_INCLUDE_DIR, "G++", 1, 1 }, \
    { GPLUSPLUS_BACKWARD_INCLUDE_DIR, "G++", 1, 1 }, \
    { NATIVE_SYSTEM_HEADER_DIR, NATIVE_SYSTEM_HEADER_COMPONENT, 0, 0 }, \
    { 0, 0, 0, 0 }				\
  }

/* Under OpenBSD, the normal location of the various *crt*.o files is the
   /usr/lib directory.  */
#undef STANDARD_STARTFILE_PREFIX
#define STANDARD_STARTFILE_PREFIX	"/usr/local/lib/"

#endif


/* Controlling the compilation driver.  */
/* TARGET_OS_CPP_BUILTINS() common to all OpenBSD targets.  */
#define OPENBSD_OS_CPP_BUILTINS()		\
  do						\
    {						\
      builtin_define ("__OpenBSD__");		\
      builtin_define ("__unix__");		\
      builtin_define ("__ANSI_COMPAT");		\
      builtin_assert ("system=unix");		\
      builtin_assert ("system=bsd");		\
      builtin_assert ("system=OpenBSD");	\
    }						\
  while (0)

/* TARGET_OS_CPP_BUILTINS() common to all OpenBSD ELF targets.  */
#define OPENBSD_OS_CPP_BUILTINS_ELF()		\
  do						\
    {						\
      OPENBSD_OS_CPP_BUILTINS();		\
      builtin_define ("__ELF__");		\
    }						\
while (0)

/* TARGET_OS_CPP_BUILTINS() common to all LP64 OpenBSD targets.  */
#define OPENBSD_OS_CPP_BUILTINS_LP64()		\
  do						\
    {						\
      builtin_define ("_LP64");			\
      builtin_define ("__LP64__");		\
    }						\
  while (0)

/* CPP_SPEC appropriate for OpenBSD. We deal with -posix and -pthread.
   XXX the way threads are handled currently is not very satisfying,
   since all code must be compiled with -pthread to work. 
   This two-stage defines makes it easy to pick that for targets that
   have subspecs.  */
#ifdef CPP_CPU_SPEC
#define OBSD_CPP_SPEC "%(cpp_cpu) %{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
#else
#define OBSD_CPP_SPEC "%{posix:-D_POSIX_SOURCE} %{pthread:-D_POSIX_THREADS}"
#endif

#undef LIB_SPEC
#define LIB_SPEC OBSD_LIB_SPEC

#ifndef OBSD_HAS_CORRECT_SPECS

#undef CPP_SPEC
#define CPP_SPEC OBSD_CPP_SPEC

#ifdef OBSD_OLD_GAS
/* ASM_SPEC appropriate for OpenBSD.  For some architectures, OpenBSD 
   still uses a special flavor of gas that needs to be told when generating 
   pic code.  */
#undef ASM_SPEC
#define ASM_SPEC "%{" FPIE1_OR_FPIC1_SPEC ":-k} %{" FPIE2_OR_FPIC2_SPEC ":-k -K}"
#endif

/* Since we use gas, stdin -> - is a good idea.  */
#define AS_NEEDS_DASH_FOR_PIPED_INPUT

#undef LIB_SPEC
#define LIB_SPEC OBSD_LIB_SPEC

#if defined(HAVE_LD_EH_FRAME_HDR)
#define LINK_EH_SPEC "%{!static|static-pie:--eh-frame-hdr} "
#endif

#undef LIB_SPEC
#define LIB_SPEC OBSD_LIB_SPEC
#endif

#define TARGET_POSIX_IO

/* All new versions of OpenBSD have C99 functions.  We redefine this hook
   so the version from elfos.h header won't be used.  */
#undef TARGET_LIBC_HAS_FUNCTION
#define TARGET_LIBC_HAS_FUNCTION default_libc_has_function


/* Runtime target specification.  */

/* Miscellaneous parameters.  */

/* Controlling debugging info: dbx options.  */

/* Don't use the `xsTAG;' construct in DBX output; OpenBSD systems that
   use DBX don't support it.  */
#define DBX_NO_XREFS


/* - we use . - _func instead of a local label,
   - we put extra spaces in expressions such as 
     .type _func , @function
     This is more readable for a human being and confuses c++filt less.  */

/* Assembler format: output and generation of labels.  */

/* Define the strings used for the .type and .size directives.
   These strings generally do not vary from one system running OpenBSD
   to another, but if a given system needs to use different pseudo-op
   names for these, they may be overridden in the arch specific file.  */ 

/* OpenBSD assembler is hacked to have .type & .size support even in a.out
   format object files.  Functions size are supported but not activated 
   yet (look for GRACE_PERIOD_EXPIRED in gas/config/obj-aout.c).  
   SET_ASM_OP is needed for attribute alias to work.  */

#undef TYPE_ASM_OP
#undef SIZE_ASM_OP
#undef SET_ASM_OP
#undef GLOBAL_ASM_OP

#define TYPE_ASM_OP	"\t.type\t"
#define SIZE_ASM_OP	"\t.size\t"
#define SET_ASM_OP	"\t.set\t"
#define GLOBAL_ASM_OP	"\t.globl\t"

/* The following macro defines the format used to output the second
   operand of the .type assembler directive.  */
#undef TYPE_OPERAND_FMT
#define TYPE_OPERAND_FMT	"@%s"

/* Provision if extra assembler code is needed to declare a function's result
   (taken from svr4, not needed yet actually).  */
#ifndef ASM_DECLARE_RESULT
#define ASM_DECLARE_RESULT(FILE, RESULT)
#endif

/* These macros generate the special .type and .size directives which
   are used to set the corresponding fields of the linker symbol table
   entries under OpenBSD.  These macros also have to output the starting 
   labels for the relevant functions/objects.  */

#ifndef OBSD_HAS_DECLARE_FUNCTION_NAME
/* Extra assembler code needed to declare a function properly.
   Some assemblers may also need to also have something extra said 
   about the function's return value.  We allow for that here.  */
#undef ASM_DECLARE_FUNCTION_NAME
#define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL)			\
  do {									\
    ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "function");			\
    ASM_DECLARE_RESULT (FILE, DECL_RESULT (DECL));			\
    ASM_OUTPUT_FUNCTION_LABEL (FILE, NAME, DECL);			\
  } while (0)
#endif

#ifndef OBSD_HAS_DECLARE_FUNCTION_SIZE
/* Declare the size of a function.  */
#undef ASM_DECLARE_FUNCTION_SIZE
#define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)		\
  do {								\
    if (!flag_inhibit_size_directive)				\
      ASM_OUTPUT_MEASURED_SIZE (FILE, FNAME);			\
  } while (0)
#endif

#ifndef OBSD_HAS_DECLARE_OBJECT
/* Extra assembler code needed to declare an object properly.  */
#undef ASM_DECLARE_OBJECT_NAME
#define ASM_DECLARE_OBJECT_NAME(FILE, NAME, DECL)		\
  do {								\
      HOST_WIDE_INT size;					\
      ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");		\
      size_directive_output = 0;				\
      if (!flag_inhibit_size_directive				\
	  && (DECL) && DECL_SIZE (DECL))			\
	{							\
	  size_directive_output = 1;				\
	  size = int_size_in_bytes (TREE_TYPE (DECL));		\
	  ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, size);		\
	}							\
      ASM_OUTPUT_LABEL (FILE, NAME);				\
  } while (0)

/* Output the size directive for a decl in rest_of_decl_compilation
   in the case where we did not do so before the initializer.
   Once we find the error_mark_node, we know that the value of
   size_directive_output was set by ASM_DECLARE_OBJECT_NAME 
   when it was run for the same decl.  */
#undef ASM_FINISH_DECLARE_OBJECT
#define ASM_FINISH_DECLARE_OBJECT(FILE, DECL, TOP_LEVEL, AT_END)	 \
do {									 \
     const char *name = XSTR (XEXP (DECL_RTL (DECL), 0), 0);		 \
     HOST_WIDE_INT size;						 \
     if (!flag_inhibit_size_directive && DECL_SIZE (DECL)		 \
         && ! AT_END && TOP_LEVEL					 \
	 && DECL_INITIAL (DECL) == error_mark_node			 \
	 && !size_directive_output)					 \
       {								 \
	 size_directive_output = 1;					 \
	 size = int_size_in_bytes (TREE_TYPE (DECL));			 \
	 ASM_OUTPUT_SIZE_DIRECTIVE (FILE, name, size);			 \
       }								 \
   } while (0)
#endif


/* Those are `generic' ways to weaken/globalize a label. We shouldn't need
   to override a processor specific definition. Hence, #ifndef ASM_*
   In case overriding turns out to be needed, one can always #undef ASM_* 
   before including this file.  */

/* Tell the assembler that a symbol is weak.  */
/* Note: netbsd arm32 assembler needs a .globl here. An override may 
   be needed when/if we go for arm32 support.  */
#ifndef ASM_WEAKEN_LABEL
#define ASM_WEAKEN_LABEL(FILE,NAME) \
  do { fputs ("\t.weak\t", FILE); assemble_name (FILE, NAME); \
       fputc ('\n', FILE); } while (0)
#endif

/* Storage layout.  */


#define HAVE_ENABLE_EXECUTE_STACK