ld/scripttempl/elf.sc

   1 #
   2 # Unusual variables checked by this code:
   3 #       NOP - four byte opcode for no-op (defaults to 0)
   4 #       DATA_ADDR - if end-of-text-plus-one-page isn't right for data start
   5 #       INITIAL_READONLY_SECTIONS - at start of text segment
   6 #       OTHER_READONLY_SECTIONS - other than .text .init .rodata ...
   7 #               (e.g., .PARISC.milli)
   8 #       OTHER_TEXT_SECTIONS - these get put in .text when relocating
   9 #       OTHER_READWRITE_SECTIONS - other than .data .bss .ctors .sdata ...
  10 #               (e.g., .PARISC.global)
  11 #       OTHER_BSS_SECTIONS - other than .bss .sbss ...
  12 #       OTHER_SECTIONS - at the end
  13 #       EXECUTABLE_SYMBOLS - symbols that must be defined for an
  14 #               executable (e.g., _DYNAMIC_LINK)
  15 #       TEXT_START_SYMBOLS - symbols that appear at the start of the
  16 #               .text section.
  17 #       DATA_START_SYMBOLS - symbols that appear at the start of the
  18 #               .data section.
  19 #       OTHER_GOT_SYMBOLS - symbols defined just before .got.
  20 #       OTHER_GOT_SECTIONS - sections just after .got.
  21 #       OTHER_SDATA_SECTIONS - sections just after .sdata.
  22 #       OTHER_BSS_SYMBOLS - symbols that appear at the start of the
  23 #               .bss section besides __bss_start.
  24 #       DATA_PLT - .plt should be in data segment, not text segment.
  25 #       BSS_PLT - .plt should be in bss segment
  26 #       TEXT_DYNAMIC - .dynamic in text segment, not data segment.
  27 #       EMBEDDED - whether this is for an embedded system.
  28 #       SHLIB_TEXT_START_ADDR - if set, add to SIZEOF_HEADERS to set
  29 #               start address of shared library.
  30 #       INPUT_FILES - INPUT command of files to always include
  31 #       WRITABLE_RODATA - if set, the .rodata section should be writable
  32 #       INIT_START, INIT_END -  statements just before and just after
  33 #       combination of .init sections.
  34 #       FINI_START, FINI_END - statements just before and just after
  35 #       combination of .fini sections.
  36 #       STACK_ADDR - start of a .stack section.
  37 #       OTHER_END_SYMBOLS - symbols to place right at the end of the script.
  38 #
  39 # When adding sections, do note that the names of some sections are used
  40 # when specifying the start address of the next.
  41 #
  42
  43 #  Many sections come in three flavours.  There is the 'real' section,
  44 #  like ".data".  Then there are the per-procedure or per-variable
  45 #  sections, generated by -ffunction-sections and -fdata-sections in GCC,
  46 #  and useful for --gc-sections, which for a variable "foo" might be
  47 #  ".data.foo".  Then there are the linkonce sections, for which the linker
  48 #  eliminates duplicates, which are named like ".gnu.linkonce.d.foo".
  49 #  The exact correspondences are:
  50 #
  51 #  Section      Linkonce section
  52 #  .text        .gnu.linkonce.t.foo
  53 #  .rodata      .gnu.linkonce.r.foo
  54 #  .data        .gnu.linkonce.d.foo
  55 #  .bss         .gnu.linkonce.b.foo
  56 #  .sdata       .gnu.linkonce.s.foo
  57 #  .sbss        .gnu.linkonce.sb.foo
  58 #  .sdata2      .gnu.linkonce.s2.foo
  59 #  .sbss2       .gnu.linkonce.sb2.foo
  60 #  .debug_info  .gnu.linkonce.wi.foo
  61 #
  62 #  Each of these can also have corresponding .rel.* and .rela.* sections.
  63
  64 test -z "$ENTRY" && ENTRY=_start
  65 test -z "${BIG_OUTPUT_FORMAT}" && BIG_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  66 test -z "${LITTLE_OUTPUT_FORMAT}" && LITTLE_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  67 if [ -z "$MACHINE" ]; then OUTPUT_ARCH=${ARCH}; else OUTPUT_ARCH=${ARCH}:${MACHINE}; fi
  68 test -z "${ELFSIZE}" && ELFSIZE=32
  69 test -z "${ALIGNMENT}" && ALIGNMENT="${ELFSIZE} / 8"
  70 test "$LD_FLAG" = "N" && DATA_ADDR=.
  71 INTERP=".interp       ${RELOCATING-0} : { *(.interp) }"
  72 PLT=".plt          ${RELOCATING-0} : { *(.plt) }"
  73 DYNAMIC=".dynamic      ${RELOCATING-0} : { *(.dynamic) }"
  74 RODATA=".rodata       ${RELOCATING-0} : { *(.rodata${RELOCATING+ .rodata.* .gnu.linkonce.r.*}) }"
  75 SBSS2=".sbss2        ${RELOCATING-0} : { *(.sbss2${RELOCATING+ .sbss2.* .gnu.linkonce.sb2.*}) }"
  76 SDATA2=".sdata2       ${RELOCATING-0} : { *(.sdata2${RELOCATING+ .sdata2.* .gnu.linkonce.s2.*}) }"
  77 CTOR=".ctors        ${CONSTRUCTING-0} :
  78   {
  79     ${CONSTRUCTING+${CTOR_START}}
  80     /* gcc uses crtbegin.o to find the start of
  81        the constructors, so we make sure it is
  82        first.  Because this is a wildcard, it
  83        doesn't matter if the user does not
  84        actually link against crtbegin.o; the
  85        linker won't look for a file to match a
  86        wildcard.  The wildcard also means that it
  87        doesn't matter which directory crtbegin.o
  88        is in.  */
  89
  90     KEEP (*crtbegin.o(.ctors))
  91
  92     /* We don't want to include the .ctor section from
  93        from the crtend.o file until after the sorted ctors.
  94        The .ctor section from the crtend file contains the
  95        end of ctors marker and it must be last */
  96
  97     KEEP (*(EXCLUDE_FILE (*crtend.o $OTHER_EXCLUDE_FILES) .ctors))
  98     KEEP (*(SORT(.ctors.*)))
  99     KEEP (*(.ctors))
 100     ${CONSTRUCTING+${CTOR_END}}
 101   }"
 102 DTOR=".dtors        ${CONSTRUCTING-0} :
 103   {
 104     ${CONSTRUCTING+${DTOR_START}}
 105     KEEP (*crtbegin.o(.dtors))
 106     KEEP (*(EXCLUDE_FILE (*crtend.o $OTHER_EXCLUDE_FILES) .dtors))
 107     KEEP (*(SORT(.dtors.*)))
 108     KEEP (*(.dtors))
 109     ${CONSTRUCTING+${DTOR_END}}
 110   }"
 111 STACK="  .stack        ${RELOCATING-0}${RELOCATING+${STACK_ADDR}} :
 112   {
 113     ${RELOCATING+_stack = .;}
 114     *(.stack)
 115   }"
 116
 117 # if this is for an embedded system, don't add SIZEOF_HEADERS.
 118 if [ -z "$EMBEDDED" ]; then
 119    test -z "${TEXT_BASE_ADDRESS}" && TEXT_BASE_ADDRESS="${TEXT_START_ADDR} + SIZEOF_HEADERS"
 120 else
 121    test -z "${TEXT_BASE_ADDRESS}" && TEXT_BASE_ADDRESS="${TEXT_START_ADDR}"
 122 fi
 123
 124 cat <<EOF
 125 OUTPUT_FORMAT("${OUTPUT_FORMAT}", "${BIG_OUTPUT_FORMAT}",
 126               "${LITTLE_OUTPUT_FORMAT}")
 127 OUTPUT_ARCH(${OUTPUT_ARCH})
 128 ENTRY(${ENTRY})
 129
 130 ${RELOCATING+${LIB_SEARCH_DIRS}}
 131 ${RELOCATING+/* Do we need any of these for elf?
 132    __DYNAMIC = 0; ${STACKZERO+${STACKZERO}} ${SHLIB_PATH+${SHLIB_PATH}}  */}
 133 ${RELOCATING+${EXECUTABLE_SYMBOLS}}
 134 ${RELOCATING+${INPUT_FILES}}
 135 ${RELOCATING- /* For some reason, the Solaris linker makes bad executables
 136   if gld -r is used and the intermediate file has sections starting
 137   at non-zero addresses.  Could be a Solaris ld bug, could be a GNU ld
 138   bug.  But for now assigning the zero vmas works.  */}
 139
 140 SECTIONS
 141 {
 142   /* Read-only sections, merged into text segment: */
 143   ${CREATE_SHLIB-${RELOCATING+. = ${TEXT_BASE_ADDRESS};}}
 144   ${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_TEXT_START_ADDR:-0} + SIZEOF_HEADERS;}}
 145   ${CREATE_SHLIB-${INTERP}}
 146   ${INITIAL_READONLY_SECTIONS}
 147   ${TEXT_DYNAMIC+${DYNAMIC}}
 148   .hash         ${RELOCATING-0} : { *(.hash) }
 149   .dynsym       ${RELOCATING-0} : { *(.dynsym) }
 150   .dynstr       ${RELOCATING-0} : { *(.dynstr) }
 151   .gnu.version  ${RELOCATING-0} : { *(.gnu.version) }
 152   .gnu.version_d ${RELOCATING-0}: { *(.gnu.version_d) }
 153   .gnu.version_r ${RELOCATING-0}: { *(.gnu.version_r) }
 154
 155 EOF
 156 if [ "x$COMBRELOC" = x ]; then
 157   COMBRELOCCAT=cat
 158 else
 159   COMBRELOCCAT="cat > $COMBRELOC"
 160 fi
 161 eval $COMBRELOCCAT <<EOF
 162   .rel.init     ${RELOCATING-0} : { *(.rel.init) }
 163   .rela.init    ${RELOCATING-0} : { *(.rela.init) }
 164   .rel.text     ${RELOCATING-0} : { *(.rel.text${RELOCATING+ .rel.text.* .rel.gnu.linkonce.t.*}) }
 165   .rela.text    ${RELOCATING-0} : { *(.rela.text${RELOCATING+ .rela.text.* .rela.gnu.linkonce.t.*}) }
 166   .rel.fini     ${RELOCATING-0} : { *(.rel.fini) }
 167   .rela.fini    ${RELOCATING-0} : { *(.rela.fini) }
 168   .rel.rodata   ${RELOCATING-0} : { *(.rel.rodata${RELOCATING+ .rel.rodata.* .rel.gnu.linkonce.r.*}) }
 169   .rela.rodata  ${RELOCATING-0} : { *(.rela.rodata${RELOCATING+ .rela.rodata.* .rela.gnu.linkonce.r.*}) }
 170   ${OTHER_READONLY_RELOC_SECTIONS}
 171   .rel.data     ${RELOCATING-0} : { *(.rel.data${RELOCATING+ .rel.data.* .rel.gnu.linkonce.d.*}) }
 172   .rela.data    ${RELOCATING-0} : { *(.rela.data${RELOCATING+ .rela.data.* .rela.gnu.linkonce.d.*}) }
 173   .rel.ctors    ${RELOCATING-0} : { *(.rel.ctors) }
 174   .rela.ctors   ${RELOCATING-0} : { *(.rela.ctors) }
 175   .rel.dtors    ${RELOCATING-0} : { *(.rel.dtors) }
 176   .rela.dtors   ${RELOCATING-0} : { *(.rela.dtors) }
 177   .rel.got      ${RELOCATING-0} : { *(.rel.got) }
 178   .rela.got     ${RELOCATING-0} : { *(.rela.got) }
 179   ${OTHER_GOT_RELOC_SECTIONS}
 180   .rel.sdata    ${RELOCATING-0} : { *(.rel.sdata${RELOCATING+ .rel.sdata.* .rel.gnu.linkonce.s.*}) }
 181   .rela.sdata   ${RELOCATING-0} : { *(.rela.sdata${RELOCATING+ .rela.sdata.* .rela.gnu.linkonce.s.*}) }
 182   .rel.sbss     ${RELOCATING-0} : { *(.rel.sbss${RELOCATING+ .rel.sbss.* .rel.gnu.linkonce.sb.*}) }
 183   .rela.sbss    ${RELOCATING-0} : { *(.rela.sbss${RELOCATING+ .rela.sbss.* .rela.gnu.linkonce.sb.*}) }
 184   .rel.sdata2   ${RELOCATING-0} : { *(.rel.sdata2${RELOCATING+ .rel.sdata2.* .rel.gnu.linkonce.s2.*}) }
 185   .rela.sdata2  ${RELOCATING-0} : { *(.rela.sdata2${RELOCATING+ .rela.sdata2.* .rela.gnu.linkonce.s2.*}) }
 186   .rel.sbss2    ${RELOCATING-0} : { *(.rel.sbss2${RELOCATING+ .rel.sbss2.* .rel.gnu.linkonce.sb2.*}) }
 187   .rela.sbss2   ${RELOCATING-0} : { *(.rela.sbss2${RELOCATING+ .rela.sbss2.* .rela.gnu.linkonce.sb2.*}) }
 188   .rel.bss      ${RELOCATING-0} : { *(.rel.bss${RELOCATING+ .rel.bss.* .rel.gnu.linkonce.b.*}) }
 189   .rela.bss     ${RELOCATING-0} : { *(.rela.bss${RELOCATING+ .rela.bss.* .rela.gnu.linkonce.b.*}) }
 190 EOF
 191 if [ -n "$COMBRELOC" ]; then
 192 cat <<EOF
 193   .rel.dyn      ${RELOCATING-0} :
 194     {
 195 EOF
 196 sed -e '/^[     ]*[{}][         ]*$/d;/:[       ]*$/d;/\.rela\./d;s/^.*: { *\(.*\)}$/      \1/' $COMBRELOC
 197 cat <<EOF
 198     }
 199   .rela.dyn     ${RELOCATING-0} :
 200     {
 201 EOF
 202 sed -e '/^[     ]*[{}][         ]*$/d;/:[       ]*$/d;/\.rel\./d;s/^.*: { *\(.*\)}/      \1/' $COMBRELOC
 203 cat <<EOF
 204     }
 205 EOF
 206 fi
 207 cat <<EOF
 208   .rel.plt      ${RELOCATING-0} : { *(.rel.plt) }
 209   .rela.plt     ${RELOCATING-0} : { *(.rela.plt) }
 210   ${OTHER_PLT_RELOC_SECTIONS}
 211
 212   .init         ${RELOCATING-0} :
 213   {
 214     ${RELOCATING+${INIT_START}}
 215     KEEP (*(.init))
 216     ${RELOCATING+${INIT_END}}
 217   } =${NOP-0}
 218
 219   ${DATA_PLT-${BSS_PLT-${PLT}}}
 220   .text         ${RELOCATING-0} :
 221   {
 222     ${RELOCATING+${TEXT_START_SYMBOLS}}
 223     *(.text .stub${RELOCATING+ .text.* .gnu.linkonce.t.*})
 224     /* .gnu.warning sections are handled specially by elf32.em.  */
 225     *(.gnu.warning)
 226     ${RELOCATING+${OTHER_TEXT_SECTIONS}}
 227   } =${NOP-0}
 228   .fini         ${RELOCATING-0} :
 229   {
 230     ${RELOCATING+${FINI_START}}
 231     KEEP (*(.fini))
 232     ${RELOCATING+${FINI_END}}
 233   } =${NOP-0}
 234   ${RELOCATING+PROVIDE (__etext = .);}
 235   ${RELOCATING+PROVIDE (_etext = .);}
 236   ${RELOCATING+PROVIDE (etext = .);}
 237   ${WRITABLE_RODATA-${RODATA}}
 238   .rodata1      ${RELOCATING-0} : { *(.rodata1) }
 239   ${CREATE_SHLIB-${SDATA2}}
 240   ${CREATE_SHLIB-${SBSS2}}
 241   ${OTHER_READONLY_SECTIONS}
 242
 243   /* Adjust the address for the data segment.  We want to adjust up to
 244      the same address within the page on the next page up.  */
 245   ${CREATE_SHLIB-${RELOCATING+. = ${DATA_ADDR-ALIGN(${MAXPAGESIZE}) + (. & (${MAXPAGESIZE} - 1))};}}
 246   ${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_DATA_ADDR-ALIGN(${MAXPAGESIZE}) + (. & (${MAXPAGESIZE} - 1))};}}
 247
 248   .data         ${RELOCATING-0} :
 249   {
 250     ${RELOCATING+${DATA_START_SYMBOLS}}
 251     *(.data${RELOCATING+ .data.* .gnu.linkonce.d.*})
 252     ${CONSTRUCTING+SORT(CONSTRUCTORS)}
 253   }
 254   .data1        ${RELOCATING-0} : { *(.data1) }
 255   .eh_frame     ${RELOCATING-0} : { KEEP (*(.eh_frame)) }
 256   .gcc_except_table ${RELOCATING-0} : { *(.gcc_except_table) }
 257   ${WRITABLE_RODATA+${RODATA}}
 258   ${OTHER_READWRITE_SECTIONS}
 259   ${TEXT_DYNAMIC-${DYNAMIC}}
 260   ${RELOCATING+${CTOR}}
 261   ${RELOCATING+${DTOR}}
 262   .jcr          ${RELOCATING-0} : { KEEP (*(.jcr)) }
 263   ${DATA_PLT+${PLT}}
 264   ${RELOCATING+${OTHER_GOT_SYMBOLS}}
 265   .got          ${RELOCATING-0} : { *(.got.plt) *(.got) }
 266   ${OTHER_GOT_SECTIONS}
 267   ${CREATE_SHLIB+${SDATA2}}
 268   ${CREATE_SHLIB+${SBSS2}}
 269   /* We want the small data sections together, so single-instruction offsets
 270      can access them all, and initialized data all before uninitialized, so
 271      we can shorten the on-disk segment size.  */
 272   .sdata        ${RELOCATING-0} :
 273   {
 274     ${RELOCATING+${SDATA_START_SYMBOLS}}
 275     *(.sdata${RELOCATING+ .sdata.* .gnu.linkonce.s.*})
 276   }
 277   ${OTHER_SDATA_SECTIONS}
 278   ${RELOCATING+_edata = .;}
 279   ${RELOCATING+PROVIDE (edata = .);}
 280   ${RELOCATING+__bss_start = .;}
 281   ${RELOCATING+${OTHER_BSS_SYMBOLS}}
 282   .sbss         ${RELOCATING-0} :
 283   {
 284     ${RELOCATING+PROVIDE (__sbss_start = .);}
 285     ${RELOCATING+PROVIDE (___sbss_start = .);}
 286     *(.dynsbss)
 287     *(.sbss${RELOCATING+ .sbss.* .gnu.linkonce.sb.*})
 288     *(.scommon)
 289     ${RELOCATING+PROVIDE (__sbss_end = .);}
 290     ${RELOCATING+PROVIDE (___sbss_end = .);}
 291   }
 292   ${BSS_PLT+${PLT}}
 293   .bss          ${RELOCATING-0} :
 294   {
 295    *(.dynbss)
 296    *(.bss${RELOCATING+ .bss.* .gnu.linkonce.b.*})
 297    *(COMMON)
 298    /* Align here to ensure that the .bss section occupies space up to
 299       _end.  Align after .bss to ensure correct alignment even if the
 300       .bss section disappears because there are no input sections.  */
 301    ${RELOCATING+. = ALIGN(${ALIGNMENT});}
 302   }
 303   ${OTHER_BSS_SECTIONS}
 304   ${RELOCATING+. = ALIGN(${ALIGNMENT});}
 305   ${RELOCATING+_end = .;}
 306   ${RELOCATING+${OTHER_BSS_END_SYMBOLS}}
 307   ${RELOCATING+PROVIDE (end = .);}
 308
 309   /* Stabs debugging sections.  */
 310   .stab          0 : { *(.stab) }
 311   .stabstr       0 : { *(.stabstr) }
 312   .stab.excl     0 : { *(.stab.excl) }
 313   .stab.exclstr  0 : { *(.stab.exclstr) }
 314   .stab.index    0 : { *(.stab.index) }
 315   .stab.indexstr 0 : { *(.stab.indexstr) }
 316
 317   .comment       0 : { *(.comment) }
 318
 319   /* DWARF debug sections.
 320      Symbols in the DWARF debugging sections are relative to the beginning
 321      of the section so we begin them at 0.  */
 322
 323   /* DWARF 1 */
 324   .debug          0 : { *(.debug) }
 325   .line           0 : { *(.line) }
 326
 327   /* GNU DWARF 1 extensions */
 328   .debug_srcinfo  0 : { *(.debug_srcinfo) }
 329   .debug_sfnames  0 : { *(.debug_sfnames) }
 330
 331   /* DWARF 1.1 and DWARF 2 */
 332   .debug_aranges  0 : { *(.debug_aranges) }
 333   .debug_pubnames 0 : { *(.debug_pubnames) }
 334
 335   /* DWARF 2 */
 336   .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
 337   .debug_abbrev   0 : { *(.debug_abbrev) }
 338   .debug_line     0 : { *(.debug_line) }
 339   .debug_frame    0 : { *(.debug_frame) }
 340   .debug_str      0 : { *(.debug_str) }
 341   .debug_loc      0 : { *(.debug_loc) }
 342   .debug_macinfo  0 : { *(.debug_macinfo) }
 343
 344   /* SGI/MIPS DWARF 2 extensions */
 345   .debug_weaknames 0 : { *(.debug_weaknames) }
 346   .debug_funcnames 0 : { *(.debug_funcnames) }
 347   .debug_typenames 0 : { *(.debug_typenames) }
 348   .debug_varnames  0 : { *(.debug_varnames) }
 349
 350   ${STACK_ADDR+${STACK}}
 351   ${OTHER_SECTIONS}
 352   ${RELOCATING+${OTHER_END_SYMBOLS}}
 353 }
 354 EOF