gcc/config/arm/netbsd.h

   1 /* NetBSD/arm (RiscBSD) version.
   2    Copyright (C) 1993, 1994, 1997 Free Software Foundation, Inc.
   3    Contributed by Mark Brinicombe (amb@physig.ph.kcl.ac.uk)
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC 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 2, or (at your option)
  10 any later version.
  11
  12 GNU CC 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 GNU CC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /* Run-time Target Specification.  */
  22 #define TARGET_VERSION fputs (" (ARM/NetBSD)", stderr);
  23
  24 /* This is used in ASM_FILE_START.  */
  25 #define ARM_OS_NAME "NetBSD"
  26
  27 /* Unsigned chars produces much better code than signed.  */
  28 #define DEFAULT_SIGNED_CHAR  0
  29
  30 /* Since we always use GAS as our assembler we support stabs.  */
  31 #define DBX_DEBUGGING_INFO 1
  32
  33 /*#undef ASM_DECLARE_FUNCTION_NAME*/
  34
  35 /* ARM6 family default cpu.  */
  36 #define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm6
  37
  38 /* Default is to use APCS-32 mode.  */
  39 #define TARGET_DEFAULT ARM_FLAG_APCS_32
  40
  41 #include "arm/aout.h"
  42
  43 /* This gets redefined in config/netbsd.h.  */
  44 #undef TARGET_MEM_FUNCTIONS
  45
  46 #include <netbsd.h>
  47
  48 /* Some defines for CPP.
  49    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  50 #undef CPP_PREDEFINES
  51 #define CPP_PREDEFINES "\
  52 -Dunix -Driscbsd -Darm32 -D__arm32__ -D__arm__ -D__NetBSD__ \
  53 -Asystem(unix) -Asystem(NetBSD) -Acpu(arm) -Amachine(arm)"
  54
  55 /* Define _POSIX_SOURCE if necessary.  */
  56 #undef CPP_SPEC
  57 #define CPP_SPEC "\
  58 %(cpp_cpu_arch) %(cpp_apcs_pc) %(cpp_float) %(cpp_endian) \
  59 %{posix:-D_POSIX_SOURCE} \
  60 "
  61
  62 /* Because TARGET_DEFAULT sets ARM_FLAG_APCS_32 */
  63 #undef CPP_APCS_PC_DEFAULT_SPEC
  64 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  65
  66 /* Pass -X to the linker so that it will strip symbols starting with 'L' */
  67 #undef LINK_SPEC
  68 #define LINK_SPEC "\
  69 -X %{!nostdlib:%{!r*:%{!e*:-e start}}} -dc -dp %{R*} \
  70 %{static:-Bstatic} %{assert*} \
  71 "
  72
  73 #undef SIZE_TYPE
  74 #define SIZE_TYPE "unsigned int"
  75
  76 #undef PTRDIFF_TYPE
  77 #define PTRDIFF_TYPE "int"
  78
  79 #undef WCHAR_TYPE
  80 #define WCHAR_TYPE "int"
  81
  82 #undef WCHAR_UNSIGNED
  83 #define WCHAR_UNSIGNED 0
  84
  85 #undef WCHAR_TYPE_SIZE
  86 #define WCHAR_TYPE_SIZE 32
  87
  88 #define HANDLE_SYSV_PRAGMA
  89
  90 /* We don't have any limit on the length as out debugger is GDB.  */
  91 #undef DBX_CONTIN_LENGTH
  92
  93 /* NetBSD does its profiling differently to the Acorn compiler. We
  94    don't need a word following the mcount call; and to skip it
  95    requires either an assembly stub or use of fomit-frame-pointer when
  96    compiling the profiling functions.  Since we break Acorn CC
  97    compatibility below a little more won't hurt.  */
  98
  99 #undef FUNCTION_PROFILER
 100 #define FUNCTION_PROFILER(STREAM,LABELNO)                                   \
 101 {                                                                           \
 102   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
 103   fprintf(STREAM, "\tbl\tmcount\n");                                        \
 104 }
 105
 106 /* On the ARM `@' introduces a comment, so we must use something else
 107    for .type directives.  */
 108 #undef TYPE_OPERAND_FMT
 109 #define TYPE_OPERAND_FMT "%%%s"
 110
 111 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 112    There are consequences you should be aware of...
 113
 114    Normally GCC/arm uses a structure alignment of 32 for compatibility
 115    with armcc.  This means that structures are padded to a word
 116    boundary.  However this causes problems with bugged NetBSD kernel
 117    code (possibly userland code as well - I have not checked every
 118    binary).  The nature of this bugged code is to rely on sizeof()
 119    returning the correct size of various structures rounded to the
 120    nearest byte (SCSI and ether code are two examples, the vm system
 121    is another).  This code breaks when the structure alignment is 32
 122    as sizeof() will report a word=rounded size.  By changing the
 123    structure alignment to 8. GCC will conform to what is expected by
 124    NetBSD.
 125
 126    This has several side effects that should be considered.
 127    1. Structures will only be aligned to the size of the largest member.
 128       i.e. structures containing only bytes will be byte aligned.
 129            structures containing shorts will be half word alinged.
 130            structures containing ints will be word aligned.
 131
 132       This means structures should be padded to a word boundary if
 133       alignment of 32 is required for byte structures etc.
 134
 135    2. A potential performance penalty may exist if strings are no longer
 136       word aligned.  GCC will not be able to use word load/stores to copy
 137       short strings.
 138
 139    This modification is not encouraged but with the present state of the
 140    NetBSD source tree it is currently the only solution that meets the
 141    requirements.  */
 142 #undef STRUCTURE_SIZE_BOUNDARY
 143 #define STRUCTURE_SIZE_BOUNDARY 8
 144
 145 /* Until they use ELF or something that handles dwarf2 unwinds
 146    and initialization stuff better.  */
 147 #define DWARF2_UNWIND_INFO 0
 148