gcc/config/arm/netbsd.h

   1 /* NetBSD/arm a.out version.
   2    Copyright (C) 1993, 1994, 1997, 1998 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, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* Run-time Target Specification.  */
  23 #undef  TARGET_VERSION
  24 #define TARGET_VERSION fputs (" (ARM/NetBSD)", stderr);
  25
  26 /* This is used in ASM_FILE_START.  */
  27 #undef ARM_OS_NAME
  28 #define ARM_OS_NAME "NetBSD"
  29
  30 /* Unsigned chars produces much better code than signed.  */
  31 #define DEFAULT_SIGNED_CHAR  0
  32
  33 /* Since we always use GAS as our assembler we support stabs.  */
  34 #define DBX_DEBUGGING_INFO 1
  35
  36 /*#undef ASM_DECLARE_FUNCTION_NAME*/
  37
  38 /* ARM6 family default cpu.  */
  39 #define SUBTARGET_CPU_DEFAULT TARGET_CPU_arm6
  40
  41 /* Default is to use APCS-32 mode.  */
  42 #undef TARGET_DEFAULT
  43 #define TARGET_DEFAULT (ARM_FLAG_APCS_32 | ARM_FLAG_SOFT_FLOAT | ARM_FLAG_APCS_FRAME)
  44
  45 /* Some defines for CPP.
  46    arm32 is the NetBSD port name, so we always define arm32 and __arm32__.  */
  47 #define TARGET_OS_CPP_BUILTINS()                \
  48     do {                                        \
  49         builtin_define_std ("arm32");           \
  50         builtin_define_std ("unix");            \
  51         builtin_define_std ("riscbsd");         \
  52         builtin_define ("__NetBSD__");          \
  53         builtin_assert ("system=unix");         \
  54         builtin_assert ("system=NetBSD");       \
  55     } while (0)
  56
  57 /* Define _POSIX_SOURCE if necessary.  */
  58 #undef CPP_SPEC
  59 #define CPP_SPEC "\
  60 %(cpp_cpu_arch) %(cpp_apcs_pc) %(cpp_float) %(cpp_endian) \
  61 %{posix:-D_POSIX_SOURCE} \
  62 "
  63
  64 /* Because TARGET_DEFAULT sets ARM_FLAG_APCS_32 */
  65 #undef CPP_APCS_PC_DEFAULT_SPEC
  66 #define CPP_APCS_PC_DEFAULT_SPEC "-D__APCS_32__"
  67
  68 /* Because TARGET_DEFAULT sets ARM_FLAG_SOFT_FLOAT */
  69 #undef CPP_FLOAT_DEFAULT_SPEC
  70 #define CPP_FLOAT_DEFAULT_SPEC "-D__SOFTFP__"
  71
  72 /* Pass -X to the linker so that it will strip symbols starting with 'L' */
  73 #undef LINK_SPEC
  74 #define LINK_SPEC "\
  75 -X %{!shared:%{!nostdlib:%{!r*:%{!e*:-e start}}} -dc -dp %{R*} \
  76 %{static:-Bstatic}} %{shared} %{assert*} \
  77 "
  78
  79 #undef SIZE_TYPE
  80 #define SIZE_TYPE "unsigned int"
  81
  82 #undef PTRDIFF_TYPE
  83 #define PTRDIFF_TYPE "int"
  84
  85 #define HANDLE_SYSV_PRAGMA
  86
  87 /* We don't have any limit on the length as out debugger is GDB.  */
  88 #undef DBX_CONTIN_LENGTH
  89
  90 /* NetBSD does its profiling differently to the Acorn compiler. We
  91    don't need a word following the mcount call; and to skip it
  92    requires either an assembly stub or use of fomit-frame-pointer when
  93    compiling the profiling functions.  Since we break Acorn CC
  94    compatibility below a little more won't hurt.  */
  95
  96 #undef  ARM_FUNCTION_PROFILER
  97 #define ARM_FUNCTION_PROFILER(STREAM,LABELNO)                               \
  98 {                                                                           \
  99   fprintf(STREAM, "\tmov\t%sip, %slr\n", REGISTER_PREFIX, REGISTER_PREFIX); \
 100   fprintf(STREAM, "\tbl\tmcount\n");                                        \
 101 }
 102
 103 /* On the ARM `@' introduces a comment, so we must use something else
 104    for .type directives.  */
 105 #undef TYPE_OPERAND_FMT
 106 #define TYPE_OPERAND_FMT "%%%s"
 107
 108 /* NetBSD uses the old PCC style aggregate returning conventions. */
 109 #undef DEFAULT_PCC_STRUCT_RETURN
 110 #define DEFAULT_PCC_STRUCT_RETURN 1
 111
 112 /* Although not normally relevant (since by default, all aggregates
 113    are returned in memory) compiling some parts of libc requires
 114    non-APCS style struct returns.  */
 115 #undef RETURN_IN_MEMORY
 116
 117 /* VERY BIG NOTE : Change of structure alignment for RiscBSD.
 118    There are consequences you should be aware of...
 119
 120    Normally GCC/arm uses a structure alignment of 32 for compatibility
 121    with armcc.  This means that structures are padded to a word
 122    boundary.  However this causes problems with bugged NetBSD kernel
 123    code (possibly userland code as well - I have not checked every
 124    binary).  The nature of this bugged code is to rely on sizeof()
 125    returning the correct size of various structures rounded to the
 126    nearest byte (SCSI and ether code are two examples, the vm system
 127    is another).  This code breaks when the structure alignment is 32
 128    as sizeof() will report a word=rounded size.  By changing the
 129    structure alignment to 8. GCC will conform to what is expected by
 130    NetBSD.
 131
 132    This has several side effects that should be considered.
 133    1. Structures will only be aligned to the size of the largest member.
 134       i.e. structures containing only bytes will be byte aligned.
 135            structures containing shorts will be half word alinged.
 136            structures containing ints will be word aligned.
 137
 138       This means structures should be padded to a word boundary if
 139       alignment of 32 is required for byte structures etc.
 140
 141    2. A potential performance penalty may exist if strings are no longer
 142       word aligned.  GCC will not be able to use word load/stores to copy
 143       short strings.
 144
 145    This modification is not encouraged but with the present state of the
 146    NetBSD source tree it is currently the only solution that meets the
 147    requirements.  */
 148 #undef  DEFAULT_STRUCTURE_SIZE_BOUNDARY
 149 #define DEFAULT_STRUCTURE_SIZE_BOUNDARY 8