gcc/config/pa/som.h

   1 /* Definitions for SOM assembler support.
   2    Copyright (C) 1999, 2001, 2002, 2003, 2004, 2005 Free Software Foundation,
   3    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 2, 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 COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* So we can conditionalize small amounts of code in pa.c or pa.md.  */
  23 #undef TARGET_SOM
  24 #define TARGET_SOM 1
  25
  26 /* We do not use BINCL stabs in SOM.
  27    ??? If it does not hurt, we probably should to avoid useless divergence
  28    from other embedded stabs implementations.  */
  29 #undef DBX_USE_BINCL
  30
  31 #define DBX_LINES_FUNCTION_RELATIVE 1
  32
  33 /* gdb needs a null N_SO at the end of each file for scattered loading.  */
  34
  35 #define DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END
  36
  37 /* Select a format to encode pointers in exception handling data.  CODE
  38    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
  39    true if the symbol may be affected by dynamic relocations.  Because
  40    the HP assembler does auto alignment, it is necessary to use
  41    DW_EH_PE_aligned instead of the default DW_EH_PE_absptr.  */
  42
  43 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE, GLOBAL) \
  44   (TARGET_GAS ? DW_EH_PE_absptr : DW_EH_PE_aligned)
  45
  46 /* HPUX has a program 'chatr' to list the dependencies of dynamically
  47    linked executables and shared libraries.  */
  48 #define LDD_SUFFIX "chatr"
  49 /* Look for lines like "dynamic   /usr/lib/X11R5/libX11.sl"
  50    or "static    /usr/lib/X11R5/libX11.sl".
  51
  52    HPUX 10.20 also has lines like "static branch prediction ..."
  53    so we filter that out explicitly.
  54
  55    We also try to bound our search for libraries with marker
  56    lines.  What a pain.  */
  57 #define PARSE_LDD_OUTPUT(PTR)                                   \
  58 do {                                                            \
  59   static int in_shlib_list = 0;                                 \
  60   while (*PTR == ' ') PTR++;                                    \
  61   if (strncmp (PTR, "shared library list:",                     \
  62                sizeof ("shared library list:") - 1) == 0)       \
  63     {                                                           \
  64       PTR = 0;                                                  \
  65       in_shlib_list = 1;                                        \
  66     }                                                           \
  67   else if (strncmp (PTR, "shared library binding:",             \
  68                     sizeof ("shared library binding:") - 1) == 0)\
  69     {                                                           \
  70       PTR = 0;                                                  \
  71       in_shlib_list = 0;                                        \
  72     }                                                           \
  73   else if (strncmp (PTR, "static branch prediction disabled",   \
  74                     sizeof ("static branch prediction disabled") - 1) == 0)\
  75     {                                                           \
  76       PTR = 0;                                                  \
  77       in_shlib_list = 0;                                        \
  78     }                                                           \
  79   else if (in_shlib_list                                        \
  80            &&  strncmp (PTR, "dynamic", sizeof ("dynamic") - 1) == 0) \
  81     {                                                           \
  82       PTR += sizeof ("dynamic") - 1;                            \
  83       while (*p == ' ') PTR++;                                  \
  84     }                                                           \
  85   else if (in_shlib_list                                        \
  86            && strncmp (PTR, "static", sizeof ("static") - 1) == 0) \
  87     {                                                           \
  88       PTR += sizeof ("static") - 1;                             \
  89       while (*p == ' ') PTR++;                                  \
  90     }                                                           \
  91   else                                                          \
  92     PTR = 0;                                                    \
  93 } while (0)
  94
  95 /* Output the label for a function definition.  */
  96 #ifndef HP_FP_ARG_DESCRIPTOR_REVERSED
  97 #define ASM_DOUBLE_ARG_DESCRIPTORS(FILE, ARG0, ARG1)    \
  98   do { fprintf (FILE, ",ARGW%d=FR", (ARG0));            \
  99        fprintf (FILE, ",ARGW%d=FU", (ARG1));} while (0)
 100 #define DFMODE_RETURN_STRING ",RTNVAL=FU"
 101 #define SFMODE_RETURN_STRING ",RTNVAL=FR"
 102 #else
 103 #define ASM_DOUBLE_ARG_DESCRIPTORS(FILE, ARG0, ARG1)    \
 104   do { fprintf (FILE, ",ARGW%d=FU", (ARG0));            \
 105        fprintf (FILE, ",ARGW%d=FR", (ARG1));} while (0)
 106 #define DFMODE_RETURN_STRING ",RTNVAL=FR"
 107 #define SFMODE_RETURN_STRING ",RTNVAL=FU"
 108 #endif
 109
 110 \f
 111 #define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL) \
 112     do { tree fntype = TREE_TYPE (TREE_TYPE (DECL));                    \
 113          tree tree_type = TREE_TYPE (DECL);                             \
 114          tree parm;                                                     \
 115          int i;                                                         \
 116          if (TREE_PUBLIC (DECL) || TARGET_GAS)                          \
 117            {                                                            \
 118              if (TREE_PUBLIC (DECL))                                    \
 119                {                                                        \
 120                  fputs ("\t.EXPORT ", FILE);                            \
 121                  assemble_name (FILE, NAME);                            \
 122                  fputs (",ENTRY,PRIV_LEV=3", FILE);                     \
 123                }                                                        \
 124              else                                                       \
 125                {                                                        \
 126                  fputs ("\t.PARAM ", FILE);                             \
 127                  assemble_name (FILE, NAME);                            \
 128                  fputs (",PRIV_LEV=3", FILE);                           \
 129                }                                                        \
 130              for (parm = DECL_ARGUMENTS (DECL), i = 0; parm && i < 4;   \
 131                   parm = TREE_CHAIN (parm))                             \
 132                {                                                        \
 133                  if (TYPE_MODE (DECL_ARG_TYPE (parm)) == SFmode         \
 134                      && ! TARGET_SOFT_FLOAT)                            \
 135                    fprintf (FILE, ",ARGW%d=FR", i++);                   \
 136                  else if (TYPE_MODE (DECL_ARG_TYPE (parm)) == DFmode    \
 137                           && ! TARGET_SOFT_FLOAT)                       \
 138                    {                                                    \
 139                      if (i <= 2)                                        \
 140                        {                                                \
 141                          if (i == 1) i++;                               \
 142                          ASM_DOUBLE_ARG_DESCRIPTORS (FILE, i++, i++);   \
 143                        }                                                \
 144                      else                                               \
 145                        break;                                           \
 146                    }                                                    \
 147                  else                                                   \
 148                    {                                                    \
 149                      int arg_size =                                     \
 150                        FUNCTION_ARG_SIZE (TYPE_MODE (DECL_ARG_TYPE (parm)),\
 151                                           DECL_ARG_TYPE (parm));        \
 152                      /* Passing structs by invisible reference uses     \
 153                         one general register.  */                       \
 154                      if (arg_size > 2                                   \
 155                          || TREE_ADDRESSABLE (DECL_ARG_TYPE (parm)))    \
 156                        arg_size = 1;                                    \
 157                      if (arg_size == 2 && i <= 2)                       \
 158                        {                                                \
 159                          if (i == 1) i++;                               \
 160                          fprintf (FILE, ",ARGW%d=GR", i++);             \
 161                          fprintf (FILE, ",ARGW%d=GR", i++);             \
 162                        }                                                \
 163                      else if (arg_size == 1)                            \
 164                        fprintf (FILE, ",ARGW%d=GR", i++);               \
 165                      else                                               \
 166                        i += arg_size;                                   \
 167                    }                                                    \
 168                }                                                        \
 169              /* anonymous args */                                       \
 170              if (TYPE_ARG_TYPES (tree_type) != 0                        \
 171                  && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (tree_type)))\
 172                      != void_type_node))                                \
 173                {                                                        \
 174                  for (; i < 4; i++)                                     \
 175                    fprintf (FILE, ",ARGW%d=GR", i);                     \
 176                }                                                        \
 177              if (TYPE_MODE (fntype) == DFmode && ! TARGET_SOFT_FLOAT)   \
 178                fputs (DFMODE_RETURN_STRING, FILE);                      \
 179              else if (TYPE_MODE (fntype) == SFmode && ! TARGET_SOFT_FLOAT) \
 180                fputs (SFMODE_RETURN_STRING, FILE);                      \
 181              else if (fntype != void_type_node)                         \
 182                fputs (",RTNVAL=GR", FILE);                              \
 183              fputs ("\n", FILE);                                        \
 184            }} while (0)
 185
 186 #define TARGET_ASM_FILE_START pa_som_file_start
 187
 188 /* String to output before text.  */
 189 #define TEXT_SECTION_ASM_OP som_text_section_asm_op ()
 190
 191 /* String to output before writable data.  */
 192 #define DATA_SECTION_ASM_OP "\t.SPACE $PRIVATE$\n\t.SUBSPA $DATA$\n"
 193
 194 /* String to output before uninitialized data.  */
 195 #define BSS_SECTION_ASM_OP "\t.SPACE $PRIVATE$\n\t.SUBSPA $BSS$\n"
 196
 197 /* FIXME: HPUX ld generates incorrect GOT entries for "T" fixups
 198    which reference data within the $TEXT$ space (for example constant
 199    strings in the $LIT$ subspace).
 200
 201    The assemblers (GAS and HP as) both have problems with handling
 202    the difference of two symbols which is the other correct way to
 203    reference constant data during PIC code generation.
 204
 205    So, there's no way to reference constant data which is in the
 206    $TEXT$ space during PIC generation.  Instead place all constant
 207    data into the $PRIVATE$ subspace (this reduces sharing, but it
 208    works correctly).  */
 209 #define READONLY_DATA_SECTION \
 210   (flag_pic ? data_section : som_readonly_data_section)
 211
 212 /* We must not have a reference to an external symbol defined in a
 213    shared library in a readonly section, else the SOM linker will
 214    complain.
 215
 216    So, we force exception information into the data section.  */
 217 #define TARGET_ASM_EXCEPTION_SECTION data_section
 218
 219 /* This is how to output a command to make the user-level label named NAME
 220    defined for reference from other files.
 221
 222    We call assemble_name, which in turn sets TREE_SYMBOL_REFERENCED.  This
 223    macro will restore the original value of TREE_SYMBOL_REFERENCED to avoid
 224    placing useless function definitions in the output file.
 225
 226    Also note that the SOM based tools need the symbol imported as a CODE
 227    symbol, while the ELF based tools require the symbol to be imported as
 228    an ENTRY symbol.  What a crock.  */
 229
 230 #define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME)   \
 231   do { int save_referenced;                                     \
 232        save_referenced = TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (DECL)); \
 233        fputs ("\t.IMPORT ", FILE);                              \
 234        assemble_name (FILE, NAME);                              \
 235        if (FUNCTION_NAME_P (NAME))                              \
 236          fputs (",CODE\n", FILE);                               \
 237        else                                                     \
 238          fputs (",DATA\n", FILE);                               \
 239        TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (DECL)) = save_referenced; \
 240      } while (0)
 241
 242 /* The bogus HP assembler requires ALL external references to be
 243    "imported", even library calls. They look a bit different, so
 244    here's this macro.
 245
 246    Also note not all libcall names are passed to pa_encode_section_info
 247    (__main for example).  To make sure all libcall names have section
 248    info recorded in them, we do it here.  We must also ensure that
 249    we don't import a libcall that has been previously exported since
 250    the HP assembler may change an ENTRY symbol to a CODE symbol.  */
 251
 252 #define ASM_OUTPUT_EXTERNAL_LIBCALL(FILE, RTL) \
 253   do { const char *name;                                                \
 254        tree id;                                                         \
 255                                                                         \
 256        if (!function_label_operand (RTL, VOIDmode))                     \
 257          hppa_encode_label (RTL);                                       \
 258                                                                         \
 259        name = targetm.strip_name_encoding (XSTR ((RTL), 0));            \
 260        id = maybe_get_identifier (name);                                \
 261        if (!id || !TREE_SYMBOL_REFERENCED (id))                         \
 262          {                                                              \
 263            fputs ("\t.IMPORT ", FILE);                                  \
 264            assemble_name (FILE, XSTR ((RTL), 0));                       \
 265            fputs (",CODE\n", FILE);                                     \
 266          }                                                              \
 267      } while (0)
 268
 269 /* We want __gcc_plt_call to appear in every program built by
 270    gcc, so we make a reference to it out of __main.
 271    We use the asm statement to fool the optimizer into not
 272    removing the dead (but important) initialization of
 273    REFERENCE.  */
 274
 275 #define DO_GLOBAL_DTORS_BODY                    \
 276 do {                                            \
 277   extern void __gcc_plt_call (void);            \
 278   void (*reference)(void) = &__gcc_plt_call;    \
 279   func_ptr *p;                                  \
 280   __asm__ ("" : : "r" (reference));             \
 281   for (p = __DTOR_LIST__ + 1; *p; )             \
 282     (*p++) ();                                  \
 283 } while (0)
 284
 285 /* This macro specifies the biggest alignment supported by the object
 286    file format of this machine.
 287
 288    The .align directive in the HP assembler allows alignments up to 4096
 289    bytes.  However, the maximum alignment of a global common symbol is 8
 290    bytes for objects smaller than the page size (4096 bytes).  For larger
 291    objects, the linker provides an alignment of 32 bytes.  Unfortunately,
 292    this macro doesn't provide a mechanism to test for common symbols.  */
 293 #define MAX_OFILE_ALIGNMENT 32768
 294
 295 /* The SOM linker hardcodes paths into binaries.  As a result, dotdots
 296    must be removed from library prefixes to prevent binaries from depending
 297    on the location of the GCC tool directory.  The downside is GCC
 298    cannot be moved after installation using a symlink.  */
 299 #define ALWAYS_STRIP_DOTDOT 1
 300
 301 /* Aggregates with a single float or double field should be passed and
 302    returned in the general registers.  */
 303 #define MEMBER_TYPE_FORCES_BLK(FIELD, MODE) (MODE==SFmode || MODE==DFmode)
 304
 305 /* If GAS supports weak, we can support weak when we have working linker
 306    support for secondary definitions and are generating code for GAS.  */
 307 #ifdef HAVE_GAS_WEAK
 308 #define SUPPORTS_WEAK (TARGET_SOM_SDEF && TARGET_GAS)
 309 #else
 310 #define SUPPORTS_WEAK 0
 311 #endif
 312
 313 /* CVS GAS as of 4/28/04 supports a comdat parameter for the .nsubspa
 314    directive.  This provides one-only linkage semantics even though we
 315    don't have weak support.  */
 316 #ifdef HAVE_GAS_NSUBSPA_COMDAT
 317 #define SUPPORTS_SOM_COMDAT (TARGET_GAS)
 318 #else
 319 #define SUPPORTS_SOM_COMDAT 0
 320 #endif
 321
 322 /* We can support one only if we support weak or comdat.  */
 323 #define SUPPORTS_ONE_ONLY (SUPPORTS_WEAK || SUPPORTS_SOM_COMDAT)
 324
 325 /* We use DECL_COMMON for uninitialized one-only variables as we don't
 326    have linkonce .bss.  We use SOM secondary definitions or comdat for
 327    initialized variables and functions.  */
 328 #define MAKE_DECL_ONE_ONLY(DECL) \
 329   do {                                                                  \
 330     if (TREE_CODE (DECL) == VAR_DECL                                    \
 331         && (DECL_INITIAL (DECL) == 0                                    \
 332             || DECL_INITIAL (DECL) == error_mark_node))                 \
 333       DECL_COMMON (DECL) = 1;                                           \
 334     else if (SUPPORTS_WEAK)                                             \
 335       DECL_WEAK (DECL) = 1;                                             \
 336   } while (0)
 337
 338 /* This is how we tell the assembler that a symbol is weak.  The SOM
 339    weak implementation uses the secondary definition (sdef) flag.
 340
 341    The behavior of sdef symbols is similar to ELF weak symbols in that
 342    multiple definitions can occur without incurring a link error.
 343    However, they differ in the following ways:
 344      1) Undefined sdef symbols are not allowed.
 345      2) The linker searches for undefined sdef symbols and will load an
 346         archive library member to resolve an undefined sdef symbol.
 347      3) The exported symbol from a shared library is a primary symbol
 348         rather than a sdef symbol.  Thus, more care is needed in the
 349         ordering of libraries.
 350
 351    It appears that the linker discards extra copies of "weak" functions
 352    when linking shared libraries, independent of whether or not they
 353    are in their own section.  In linking final executables, -Wl,-O can
 354    be used to remove dead procedures.  Thus, support for named sections
 355    is not needed and in previous testing caused problems with various
 356    HP tools.  */
 357 #define ASM_WEAKEN_LABEL(FILE,NAME) \
 358   do { fputs ("\t.weak\t", FILE);                               \
 359        assemble_name (FILE, NAME);                              \
 360        fputc ('\n', FILE);                                      \
 361        if (! FUNCTION_NAME_P (NAME))                            \
 362          {                                                      \
 363            fputs ("\t.EXPORT ", FILE);                          \
 364            assemble_name (FILE, NAME);                          \
 365            fputs (",DATA\n", FILE);                             \
 366          }                                                      \
 367   } while (0)
 368
 369 /* We can't handle weak aliases, and therefore can't support pragma weak.
 370    Suppress the use of pragma weak in gthr-dce.h and gthr-posix.h.  */
 371 #define GTHREAD_USE_WEAK 0