gcc/config/alpha/elf.h

   1 /* Definitions of target machine for GNU compiler, for DEC Alpha w/ELF.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2007, 2008,
   3    2009, 2010, 2011, 2012 Free Software Foundation, Inc.
   4    Contributed by Richard Henderson (rth@tamu.edu).
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 3, or (at your option)
  11 any later version.
  12
  13 GCC is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22 #undef  CC1_SPEC
  23 #define CC1_SPEC  "%{G*}"
  24
  25 #undef  ASM_SPEC
  26 #define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug}"
  27
  28 /* Do not output a .file directive at the beginning of the input file.  */
  29
  30 #undef  TARGET_ASM_FILE_START_FILE_DIRECTIVE
  31 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE false
  32
  33 /* This is how to output an assembler line
  34    that says to advance the location counter
  35    to a multiple of 2**LOG bytes.  */
  36
  37 #define ASM_OUTPUT_ALIGN(FILE,LOG)              \
  38   if ((LOG) != 0)                               \
  39     fprintf (FILE, "\t.align %d\n", LOG);
  40
  41 /* This says how to output assembler code to declare an
  42    uninitialized internal linkage data object.  Under SVR4,
  43    the linker seems to want the alignment of data objects
  44    to depend on their types.  We do exactly that here.  */
  45
  46 #undef  ASM_OUTPUT_ALIGNED_LOCAL
  47 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)               \
  48 do {                                                                    \
  49   if ((SIZE) <= (unsigned HOST_WIDE_INT) g_switch_value)                \
  50     switch_to_section (sbss_section);                                   \
  51   else                                                                  \
  52     switch_to_section (bss_section);                                    \
  53   ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");                     \
  54   if (!flag_inhibit_size_directive)                                     \
  55     ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, SIZE);                       \
  56   ASM_OUTPUT_ALIGN ((FILE), exact_log2((ALIGN) / BITS_PER_UNIT));       \
  57   ASM_OUTPUT_LABEL(FILE, NAME);                                         \
  58   ASM_OUTPUT_SKIP((FILE), (SIZE) ? (SIZE) : 1);                         \
  59 } while (0)
  60
  61 /* This says how to output assembler code to declare an
  62    uninitialized external linkage data object.  */
  63
  64 #undef  ASM_OUTPUT_ALIGNED_BSS
  65 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN)           \
  66 do {                                                                    \
  67   ASM_OUTPUT_ALIGNED_LOCAL (FILE, NAME, SIZE, ALIGN);                   \
  68 } while (0)
  69
  70 #undef  BSS_SECTION_ASM_OP
  71 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
  72 #undef  SBSS_SECTION_ASM_OP
  73 #define SBSS_SECTION_ASM_OP     "\t.section\t.sbss,\"aw\""
  74 #undef  SDATA_SECTION_ASM_OP
  75 #define SDATA_SECTION_ASM_OP    "\t.section\t.sdata,\"aw\""
  76
  77 /* This is how we tell the assembler that two symbols have the same value.  */
  78
  79 #undef  ASM_OUTPUT_DEF
  80 #define ASM_OUTPUT_DEF(FILE, ALIAS, NAME)                       \
  81   do {                                                          \
  82     assemble_name(FILE, ALIAS);                                 \
  83     fputs(" = ", FILE);                                         \
  84     assemble_name(FILE, NAME);                                  \
  85     fputc('\n', FILE);                                          \
  86   } while (0)
  87
  88 #undef  ASM_OUTPUT_DEF_FROM_DECLS
  89 #define ASM_OUTPUT_DEF_FROM_DECLS(FILE, DECL, TARGET)           \
  90   do {                                                          \
  91     const char *alias = XSTR (XEXP (DECL_RTL (DECL), 0), 0);    \
  92     const char *name = IDENTIFIER_POINTER (TARGET);             \
  93     if (TREE_CODE (DECL) == FUNCTION_DECL)                      \
  94       {                                                         \
  95         fputc ('$', FILE);                                      \
  96         assemble_name (FILE, alias);                            \
  97         fputs ("..ng = $", FILE);                               \
  98         assemble_name (FILE, name);                             \
  99         fputs ("..ng\n", FILE);                                 \
 100       }                                                         \
 101     ASM_OUTPUT_DEF (FILE, alias, name);                         \
 102   } while (0)
 103
 104 /* Provide a STARTFILE_SPEC appropriate for ELF.  Here we add the
 105    (even more) magical crtbegin.o file which provides part of the
 106    support for getting C++ file-scope static object constructed
 107    before entering `main'.  */
 108
 109 #undef  STARTFILE_SPEC
 110 #ifdef HAVE_LD_PIE
 111 #define STARTFILE_SPEC \
 112   "%{!shared: %{pg|p:gcrt1.o%s;pie:Scrt1.o%s;:crt1.o%s}}\
 113    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 114 #else
 115 #define STARTFILE_SPEC \
 116   "%{!shared: %{pg|p:gcrt1.o%s;:crt1.o%s}}\
 117    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 118 #endif
 119
 120 /* Provide a ENDFILE_SPEC appropriate for ELF.  Here we tack on the
 121    magical crtend.o file which provides part of the support for
 122    getting C++ file-scope static object constructed before entering
 123    `main', followed by a normal ELF "finalizer" file, `crtn.o'.  */
 124
 125 #undef  ENDFILE_SPEC
 126 #define ENDFILE_SPEC \
 127   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
 128    %{shared|pie:crtendS.o%s;:crtend.o%s} crtn.o%s"
 129
 130 /* Select a format to encode pointers in exception handling data.  CODE
 131    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
 132    true if the symbol may be affected by dynamic relocations.
 133
 134    Since application size is already constrained to <2GB by the form of
 135    the ldgp relocation, we can use a 32-bit pc-relative relocation to
 136    static data.  Dynamic data is accessed indirectly to allow for read
 137    only EH sections.  */
 138 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)       \
 139   (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
 140
 141 /* If defined, a C statement to be executed just prior to the output of
 142    assembler code for INSN.  */
 143 #define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS)      \
 144  (alpha_this_literal_sequence_number = 0,               \
 145   alpha_this_gpdisp_sequence_number = 0)
 146 extern int alpha_this_literal_sequence_number;
 147 extern int alpha_this_gpdisp_sequence_number;
 148
 149 /* Since the bits of the _init and _fini function is spread across
 150    many object files, each potentially with its own GP, we must assume
 151    we need to load our GP.  Further, the .init/.fini section can
 152    easily be more than 4MB away from the function to call so we can't
 153    use bsr.  */
 154 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 155    asm (SECTION_OP "\n"                                 \
 156 "       br $29,1f\n"                                    \
 157 "1:     ldgp $29,0($29)\n"                              \
 158 "       unop\n"                                         \
 159 "       jsr $26," USER_LABEL_PREFIX #FUNC "\n"          \
 160 "       .align 3\n"                                     \
 161 "       .previous");
 162
 163 /* If we have the capability create headers for efficient EH lookup.
 164    As of Jan 2002, only glibc 2.2.4 can actually make use of this, but
 165    I imagine that other systems will catch up.  In the meantime, it
 166    doesn't harm to make sure that the data exists to be used later.  */
 167 #if defined(HAVE_LD_EH_FRAME_HDR)
 168 #define LINK_EH_SPEC "%{!static:--eh-frame-hdr} "
 169 #endif