gcc/config/alpha/elf.h

   1 /* Definitions of target machine for GNU compiler, for DEC Alpha w/ELF.
   2    Copyright (C) 1996-2018 Free Software Foundation, Inc.
   3    Contributed by Richard Henderson (rth@tamu.edu).
   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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #undef  CC1_SPEC
  22 #define CC1_SPEC  "%{G*}"
  23
  24 #undef  ASM_SPEC
  25 #define ASM_SPEC  "%{G*} %{relax:-relax} %{!gstabs*:-no-mdebug}%{gstabs*:-mdebug} %{mcpu=*:-m%*}"
  26
  27 /* Do not output a .file directive at the beginning of the input file.  */
  28
  29 #undef  TARGET_ASM_FILE_START_FILE_DIRECTIVE
  30 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE false
  31
  32 /* This is how to output an assembler line
  33    that says to advance the location counter
  34    to a multiple of 2**LOG bytes.  */
  35
  36 #define ASM_OUTPUT_ALIGN(FILE,LOG)              \
  37   if ((LOG) != 0)                               \
  38     fprintf (FILE, "\t.align %d\n", LOG);
  39
  40 /* This says how to output assembler code to declare an
  41    uninitialized internal linkage data object.  Under SVR4,
  42    the linker seems to want the alignment of data objects
  43    to depend on their types.  We do exactly that here.  */
  44
  45 #undef  ASM_OUTPUT_ALIGNED_LOCAL
  46 #define ASM_OUTPUT_ALIGNED_LOCAL(FILE, NAME, SIZE, ALIGN)               \
  47 do {                                                                    \
  48   if ((SIZE) <= (unsigned HOST_WIDE_INT) g_switch_value)                \
  49     switch_to_section (sbss_section);                                   \
  50   else                                                                  \
  51     switch_to_section (bss_section);                                    \
  52   ASM_OUTPUT_TYPE_DIRECTIVE (FILE, NAME, "object");                     \
  53   if (!flag_inhibit_size_directive)                                     \
  54     ASM_OUTPUT_SIZE_DIRECTIVE (FILE, NAME, SIZE);                       \
  55   ASM_OUTPUT_ALIGN ((FILE), exact_log2((ALIGN) / BITS_PER_UNIT));       \
  56   ASM_OUTPUT_LABEL(FILE, NAME);                                         \
  57   ASM_OUTPUT_SKIP((FILE), (SIZE) ? (SIZE) : 1);                         \
  58 } while (0)
  59
  60 /* This says how to output assembler code to declare an
  61    uninitialized external linkage data object.  */
  62
  63 #undef  ASM_OUTPUT_ALIGNED_BSS
  64 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN)           \
  65 do {                                                                    \
  66   ASM_OUTPUT_ALIGNED_LOCAL (FILE, NAME, SIZE, ALIGN);                   \
  67 } while (0)
  68
  69 #undef  BSS_SECTION_ASM_OP
  70 #define BSS_SECTION_ASM_OP      "\t.section\t.bss"
  71 #undef  SBSS_SECTION_ASM_OP
  72 #define SBSS_SECTION_ASM_OP     "\t.section\t.sbss,\"aw\""
  73 #undef  SDATA_SECTION_ASM_OP
  74 #define SDATA_SECTION_ASM_OP    "\t.section\t.sdata,\"aw\""
  75
  76 /* This is how we tell the assembler that two symbols have the same value.  */
  77
  78 #undef  ASM_OUTPUT_DEF
  79 #define ASM_OUTPUT_DEF(FILE, ALIAS, NAME)                       \
  80   do {                                                          \
  81     assemble_name(FILE, ALIAS);                                 \
  82     fputs(" = ", FILE);                                         \
  83     assemble_name(FILE, NAME);                                  \
  84     fputc('\n', FILE);                                          \
  85   } while (0)
  86
  87 #undef  ASM_OUTPUT_DEF_FROM_DECLS
  88 #define ASM_OUTPUT_DEF_FROM_DECLS(FILE, DECL, TARGET)           \
  89   do {                                                          \
  90     const char *alias = XSTR (XEXP (DECL_RTL (DECL), 0), 0);    \
  91     const char *name = IDENTIFIER_POINTER (TARGET);             \
  92     if (TREE_CODE (DECL) == FUNCTION_DECL)                      \
  93       {                                                         \
  94         fputc ('$', FILE);                                      \
  95         assemble_name (FILE, alias);                            \
  96         fputs ("..ng = $", FILE);                               \
  97         assemble_name (FILE, name);                             \
  98         fputs ("..ng\n", FILE);                                 \
  99       }                                                         \
 100     ASM_OUTPUT_DEF (FILE, alias, name);                         \
 101   } while (0)
 102
 103 /* Provide a STARTFILE_SPEC appropriate for ELF.  Here we add the
 104    (even more) magical crtbegin.o file which provides part of the
 105    support for getting C++ file-scope static object constructed
 106    before entering `main'.  */
 107
 108 #undef  STARTFILE_SPEC
 109 #ifdef HAVE_LD_PIE
 110 #define STARTFILE_SPEC \
 111   "%{!shared: %{pg|p:gcrt1.o%s;pie:Scrt1.o%s;:crt1.o%s}}\
 112    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 113 #else
 114 #define STARTFILE_SPEC \
 115   "%{!shared: %{pg|p:gcrt1.o%s;:crt1.o%s}}\
 116    crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}"
 117 #endif
 118
 119 /* Provide a ENDFILE_SPEC appropriate for ELF.  Here we tack on the
 120    magical crtend.o file which provides part of the support for
 121    getting C++ file-scope static object constructed before entering
 122    `main', followed by a normal ELF "finalizer" file, `crtn.o'.  */
 123
 124 #undef  ENDFILE_SPEC
 125 #define ENDFILE_SPEC \
 126   "%{Ofast|ffast-math|funsafe-math-optimizations:crtfastmath.o%s} \
 127    %{shared|pie:crtendS.o%s;:crtend.o%s} crtn.o%s"
 128
 129 /* This variable should be set to 'true' if the target ABI requires
 130    unwinding tables even when exceptions are not used.  */
 131 #define TARGET_UNWIND_TABLES_DEFAULT true
 132
 133 /* Select a format to encode pointers in exception handling data.  CODE
 134    is 0 for data, 1 for code labels, 2 for function pointers.  GLOBAL is
 135    true if the symbol may be affected by dynamic relocations.
 136
 137    Since application size is already constrained to <2GB by the form of
 138    the ldgp relocation, we can use a 32-bit pc-relative relocation to
 139    static data.  Dynamic data is accessed indirectly to allow for read
 140    only EH sections.  */
 141 #define ASM_PREFERRED_EH_DATA_FORMAT(CODE,GLOBAL)       \
 142   (((GLOBAL) ? DW_EH_PE_indirect : 0) | DW_EH_PE_pcrel | DW_EH_PE_sdata4)
 143
 144 /* If defined, a C statement to be executed just prior to the output of
 145    assembler code for INSN.  */
 146 #define FINAL_PRESCAN_INSN(INSN, OPVEC, NOPERANDS)      \
 147  (alpha_this_literal_sequence_number = 0,               \
 148   alpha_this_gpdisp_sequence_number = 0)
 149 extern int alpha_this_literal_sequence_number;
 150 extern int alpha_this_gpdisp_sequence_number;
 151
 152 /* Since the bits of the _init and _fini function is spread across
 153    many object files, each potentially with its own GP, we must assume
 154    we need to load our GP.  Further, the .init/.fini section can
 155    easily be more than 4MB away from the function to call so we can't
 156    use bsr.  */
 157 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 158    asm (SECTION_OP "\n"                                 \
 159 "       br $29,1f\n"                                    \
 160 "1:     ldgp $29,0($29)\n"                              \
 161 "       unop\n"                                         \
 162 "       jsr $26," USER_LABEL_PREFIX #FUNC "\n"          \
 163 "       .align 3\n"                                     \
 164 "       .previous");
 165
 166 /* If we have the capability create headers for efficient EH lookup.
 167    As of Jan 2002, only glibc 2.2.4 can actually make use of this, but
 168    I imagine that other systems will catch up.  In the meantime, it
 169    doesn't harm to make sure that the data exists to be used later.  */
 170 #if defined(HAVE_LD_EH_FRAME_HDR)
 171 #define LINK_EH_SPEC "%{!static|static-pie:--eh-frame-hdr} "
 172 #endif