ld/scripttempl/elf.sc

   1 #
   2 # Unusual variables checked by this code:
   3 #       NOP - two 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 #
  37 # When adding sections, do note that the names of some sections are used
  38 # when specifying the start address of the next.
  39 #
  40
  41 #  Many sections come in three flavours.  There is the 'real' section,
  42 #  like ".data".  Then there are the per-procedure or per-variable
  43 #  sections, generated by -ffunction-sections and -fdata-sections in GCC,
  44 #  and useful for --gc-sections, which for a variable "foo" might be
  45 #  ".data.foo".  Then there are the linkonce sections, for which the linker
  46 #  eliminates duplicates, which are named like ".gnu.linkonce.d.foo".
  47 #  The exact correspondences are:
  48 #
  49 #  Section      Linkonce section
  50 #  .text        .gnu.linkonce.t.foo
  51 #  .rodata      .gnu.linkonce.r.foo
  52 #  .data        .gnu.linkonce.d.foo
  53 #  .bss         .gnu.linkonce.b.foo
  54 #  .sdata       .gnu.linkonce.s.foo
  55 #  .sbss        .gnu.linkonce.sb.foo
  56 #  .sdata2      .gnu.linkonce.s2.foo
  57 #  .sbss2       .gnu.linkonce.sb2.foo
  58 #
  59 #  Each of these can also have corresponding .rel.* and .rela.* sections.
  60
  61 test -z "$ENTRY" && ENTRY=_start
  62 test -z "${BIG_OUTPUT_FORMAT}" && BIG_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  63 test -z "${LITTLE_OUTPUT_FORMAT}" && LITTLE_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  64 if [ -z "$MACHINE" ]; then OUTPUT_ARCH=${ARCH}; else OUTPUT_ARCH=${ARCH}:${MACHINE}; fi
  65 test -z "${ELFSIZE}" && ELFSIZE=32
  66 test -z "${ALIGNMENT}" && ALIGNMENT="${ELFSIZE} / 8"
  67 test "$LD_FLAG" = "N" && DATA_ADDR=.
  68 INTERP=".interp   ${RELOCATING-0} : { *(.interp)        }"
  69 PLT=".plt    ${RELOCATING-0} : { *(.plt)        }"
  70 DYNAMIC=".dynamic     ${RELOCATING-0} : { *(.dynamic) }"
  71 RODATA=".rodata ${RELOCATING-0} : { *(.rodata) ${RELOCATING+*(.rodata.*)} ${RELOCATING+*(.gnu.linkonce.r.*)} }"
  72 SBSS2=".sbss2 ${RELOCATING-0} : { *(.sbss2) ${RELOCATING+*(.sbss2.*)} ${RELOCATING+*(.gnu.linkonce.sb2.*)} }"
  73 SDATA2=".sdata2 ${RELOCATING-0} : { *(.sdata2) ${RELOCATING+*(.sdata2.*)} ${RELOCATING+*(.gnu.linkonce.s2.*)} }"
  74 CTOR=".ctors ${CONSTRUCTING-0} :
  75   {
  76     ${CONSTRUCTING+${CTOR_START}}
  77     /* gcc uses crtbegin.o to find the start of
  78        the constructors, so we make sure it is
  79        first.  Because this is a wildcard, it
  80        doesn't matter if the user does not
  81        actually link against crtbegin.o; the
  82        linker won't look for a file to match a
  83        wildcard.  The wildcard also means that it
  84        doesn't matter which directory crtbegin.o
  85        is in.  */
  86
  87     KEEP (*crtbegin.o(.ctors))
  88
  89     /* We don't want to include the .ctor section from
  90        from the crtend.o file until after the sorted ctors.
  91        The .ctor section from the crtend file contains the
  92        end of ctors marker and it must be last */
  93
  94     KEEP (*(EXCLUDE_FILE (*crtend.o $OTHER_EXCLUDE_FILES) .ctors))
  95     KEEP (*(SORT(.ctors.*)))
  96     KEEP (*(.ctors))
  97     ${CONSTRUCTING+${CTOR_END}}
  98   }"
  99
 100 DTOR=" .dtors       ${CONSTRUCTING-0} :
 101   {
 102     ${CONSTRUCTING+${DTOR_START}}
 103     KEEP (*crtbegin.o(.dtors))
 104     KEEP (*(EXCLUDE_FILE (*crtend.o $OTHER_EXCLUDE_FILES) .dtors))
 105     KEEP (*(SORT(.dtors.*)))
 106     KEEP (*(.dtors))
 107     ${CONSTRUCTING+${DTOR_END}}
 108   }"
 109
 110 # if this is for an embedded system, don't add SIZEOF_HEADERS.
 111 if [ -z "$EMBEDDED" ]; then
 112    test -z "${TEXT_BASE_ADDRESS}" && TEXT_BASE_ADDRESS="${TEXT_START_ADDR} + SIZEOF_HEADERS"
 113 else
 114    test -z "${TEXT_BASE_ADDRESS}" && TEXT_BASE_ADDRESS="${TEXT_START_ADDR}"
 115 fi
 116
 117 cat <<EOF
 118 OUTPUT_FORMAT("${OUTPUT_FORMAT}", "${BIG_OUTPUT_FORMAT}",
 119               "${LITTLE_OUTPUT_FORMAT}")
 120 OUTPUT_ARCH(${OUTPUT_ARCH})
 121 ENTRY(${ENTRY})
 122
 123 ${RELOCATING+${LIB_SEARCH_DIRS}}
 124 ${RELOCATING+/* Do we need any of these for elf?
 125    __DYNAMIC = 0; ${STACKZERO+${STACKZERO}} ${SHLIB_PATH+${SHLIB_PATH}}  */}
 126 ${RELOCATING+${EXECUTABLE_SYMBOLS}}
 127 ${RELOCATING+${INPUT_FILES}}
 128 ${RELOCATING- /* For some reason, the Solaris linker makes bad executables
 129   if gld -r is used and the intermediate file has sections starting
 130   at non-zero addresses.  Could be a Solaris ld bug, could be a GNU ld
 131   bug.  But for now assigning the zero vmas works.  */}
 132
 133 SECTIONS
 134 {
 135   /* Read-only sections, merged into text segment: */
 136   ${CREATE_SHLIB-${RELOCATING+. = ${TEXT_BASE_ADDRESS};}}
 137   ${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_TEXT_START_ADDR:-0} + SIZEOF_HEADERS;}}
 138   ${CREATE_SHLIB-${INTERP}}
 139   ${INITIAL_READONLY_SECTIONS}
 140   ${TEXT_DYNAMIC+${DYNAMIC}}
 141   .hash        ${RELOCATING-0} : { *(.hash)             }
 142   .dynsym      ${RELOCATING-0} : { *(.dynsym)           }
 143   .dynstr      ${RELOCATING-0} : { *(.dynstr)           }
 144   .gnu.version ${RELOCATING-0} : { *(.gnu.version)      }
 145   .gnu.version_d ${RELOCATING-0} : { *(.gnu.version_d)  }
 146   .gnu.version_r ${RELOCATING-0} : { *(.gnu.version_r)  }
 147
 148   .rel.init    ${RELOCATING-0} : { *(.rel.init) }
 149   .rela.init   ${RELOCATING-0} : { *(.rela.init)        }
 150   .rel.text    ${RELOCATING-0} :
 151     {
 152       *(.rel.text)
 153       ${RELOCATING+*(.rel.text.*)}
 154       ${RELOCATING+*(.rel.gnu.linkonce.t.*)}
 155     }
 156   .rela.text   ${RELOCATING-0} :
 157     {
 158       *(.rela.text)
 159       ${RELOCATING+*(.rela.text.*)}
 160       ${RELOCATING+*(.rela.gnu.linkonce.t.*)}
 161     }
 162   .rel.fini    ${RELOCATING-0} : { *(.rel.fini) }
 163   .rela.fini   ${RELOCATING-0} : { *(.rela.fini)        }
 164   .rel.rodata  ${RELOCATING-0} :
 165     {
 166       *(.rel.rodata)
 167       ${RELOCATING+*(.rel.rodata.*)}
 168       ${RELOCATING+*(.rel.gnu.linkonce.r.*)}
 169     }
 170   .rela.rodata ${RELOCATING-0} :
 171     {
 172       *(.rela.rodata)
 173       ${RELOCATING+*(.rela.rodata.*)}
 174       ${RELOCATING+*(.rela.gnu.linkonce.r.*)}
 175     }
 176   ${OTHER_READONLY_RELOC_SECTIONS}
 177   .rel.data    ${RELOCATING-0} :
 178     {
 179       *(.rel.data)
 180       ${RELOCATING+*(.rel.data.*)}
 181       ${RELOCATING+*(.rel.gnu.linkonce.d.*)}
 182     }
 183   .rela.data   ${RELOCATING-0} :
 184     {
 185       *(.rela.data)
 186       ${RELOCATING+*(.rela.data.*)}
 187       ${RELOCATING+*(.rela.gnu.linkonce.d.*)}
 188     }
 189   .rel.ctors   ${RELOCATING-0} : { *(.rel.ctors)        }
 190   .rela.ctors  ${RELOCATING-0} : { *(.rela.ctors)       }
 191   .rel.dtors   ${RELOCATING-0} : { *(.rel.dtors)        }
 192   .rela.dtors  ${RELOCATING-0} : { *(.rela.dtors)       }
 193   .rel.got     ${RELOCATING-0} : { *(.rel.got)          }
 194   .rela.got    ${RELOCATING-0} : { *(.rela.got)         }
 195   ${OTHER_GOT_RELOC_SECTIONS}
 196   .rel.sdata   ${RELOCATING-0} :
 197     {
 198       *(.rel.sdata)
 199       ${RELOCATING+*(.rel.sdata.*)}
 200       ${RELOCATING+*(.rel.gnu.linkonce.s.*)}
 201     }
 202   .rela.sdata   ${RELOCATING-0} :
 203     {
 204       *(.rela.sdata)
 205       ${RELOCATING+*(.rela.sdata.*)}
 206       ${RELOCATING+*(.rela.gnu.linkonce.s.*)}
 207     }
 208   .rel.sbss    ${RELOCATING-0} :
 209     {
 210       *(.rel.sbss)
 211       ${RELOCATING+*(.rel.sbss.*)}
 212       ${RELOCATING+*(.rel.gnu.linkonce.sb.*)}
 213     }
 214   .rela.sbss   ${RELOCATING-0} :
 215     {
 216       *(.rela.sbss)
 217       ${RELOCATING+*(.rela.sbss.*)}
 218       ${RELOCATING+*(.rel.gnu.linkonce.sb.*)}
 219     }
 220   .rel.sdata2  ${RELOCATING-0} :
 221     {
 222       *(.rel.sdata2)
 223       ${RELOCATING+*(.rel.sdata2.*)}
 224       ${RELOCATING+*(.rel.gnu.linkonce.s2.*)}
 225     }
 226   .rela.sdata2 ${RELOCATING-0} :
 227     {
 228       *(.rela.sdata2)
 229       ${RELOCATING+*(.rela.sdata2.*)}
 230       ${RELOCATING+*(.rela.gnu.linkonce.s2.*)}
 231     }
 232   .rel.sbss2   ${RELOCATING-0} :
 233     {
 234       *(.rel.sbss2)
 235       ${RELOCATING+*(.rel.sbss2.*)}
 236       ${RELOCATING+*(.rel.gnu.linkonce.sb2.*)}
 237     }
 238   .rela.sbss2  ${RELOCATING-0} :
 239     {
 240       *(.rela.sbss2)
 241       ${RELOCATING+*(.rela.sbss2.*)}
 242       ${RELOCATING+*(.rela.gnu.linkonce.sb2.*)}
 243     }
 244   .rel.bss     ${RELOCATING-0} :
 245     {
 246       *(.rel.bss)
 247       ${RELOCATING+*(.rel.bss.*)}
 248       ${RELOCATING+*(.rel.gnu.linkonce.b.*)}
 249     }
 250   .rela.bss    ${RELOCATING-0} :
 251     {
 252       *(.rela.bss)
 253       ${RELOCATING+*(.rela.bss.*)}
 254       ${RELOCATING+*(.rela.gnu.linkonce.b.*)}
 255     }
 256   .rel.plt     ${RELOCATING-0} : { *(.rel.plt)          }
 257   .rela.plt    ${RELOCATING-0} : { *(.rela.plt)         }
 258   ${OTHER_PLT_RELOC_SECTIONS}
 259
 260   .init        ${RELOCATING-0} :
 261   {
 262     ${RELOCATING+${INIT_START}}
 263     KEEP (*(.init))
 264     ${RELOCATING+${INIT_END}}
 265   } =${NOP-0}
 266
 267   ${DATA_PLT-${BSS_PLT-${PLT}}}
 268   .text    ${RELOCATING-0} :
 269   {
 270     ${RELOCATING+${TEXT_START_SYMBOLS}}
 271     *(.text)
 272     ${RELOCATING+*(.text.*)}
 273     *(.stub)
 274     /* .gnu.warning sections are handled specially by elf32.em.  */
 275     *(.gnu.warning)
 276     ${RELOCATING+*(.gnu.linkonce.t.*)}
 277     ${RELOCATING+${OTHER_TEXT_SECTIONS}}
 278   } =${NOP-0}
 279   .fini    ${RELOCATING-0} :
 280   {
 281     ${RELOCATING+${FINI_START}}
 282     KEEP (*(.fini))
 283     ${RELOCATING+${FINI_END}}
 284   } =${NOP-0}
 285   ${RELOCATING+PROVIDE (__etext = .);}
 286   ${RELOCATING+PROVIDE (_etext = .);}
 287   ${RELOCATING+PROVIDE (etext = .);}
 288   ${WRITABLE_RODATA-${RODATA}}
 289   .rodata1 ${RELOCATING-0} : { *(.rodata1) }
 290   ${CREATE_SHLIB-${SDATA2}}
 291   ${CREATE_SHLIB-${SBSS2}}
 292   ${RELOCATING+${OTHER_READONLY_SECTIONS}}
 293
 294   /* Adjust the address for the data segment.  We want to adjust up to
 295      the same address within the page on the next page up.  */
 296   ${CREATE_SHLIB-${RELOCATING+. = ${DATA_ADDR-ALIGN(${MAXPAGESIZE}) + (. & (${MAXPAGESIZE} - 1))};}}
 297   ${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_DATA_ADDR-ALIGN(${MAXPAGESIZE}) + (. & (${MAXPAGESIZE} - 1))};}}
 298
 299   .data  ${RELOCATING-0} :
 300   {
 301     ${RELOCATING+${DATA_START_SYMBOLS}}
 302     *(.data)
 303     ${RELOCATING+*(.data.*)}
 304     ${RELOCATING+*(.gnu.linkonce.d.*)}
 305     ${CONSTRUCTING+SORT(CONSTRUCTORS)}
 306   }
 307   .data1 ${RELOCATING-0} : { *(.data1) }
 308   .eh_frame : { KEEP (*(.eh_frame)) }
 309   .gcc_except_table : { *(.gcc_except_table) }
 310   ${WRITABLE_RODATA+${RODATA}}
 311   ${RELOCATING+${OTHER_READWRITE_SECTIONS}}
 312   ${TEXT_DYNAMIC-${DYNAMIC}}
 313   ${RELOCATING+${CTOR}}
 314   ${RELOCATING+${DTOR}}
 315   ${DATA_PLT+${PLT}}
 316   ${RELOCATING+${OTHER_GOT_SYMBOLS}}
 317   .got          ${RELOCATING-0} : { *(.got.plt) *(.got) }
 318   ${RELOCATING+${OTHER_GOT_SECTIONS}}
 319   ${CREATE_SHLIB+${SDATA2}}
 320   ${CREATE_SHLIB+${SBSS2}}
 321   /* We want the small data sections together, so single-instruction offsets
 322      can access them all, and initialized data all before uninitialized, so
 323      we can shorten the on-disk segment size.  */
 324   .sdata   ${RELOCATING-0} :
 325   {
 326     ${RELOCATING+${SDATA_START_SYMBOLS}}
 327     *(.sdata)
 328     ${RELOCATING+*(.sdata.*)}
 329     ${RELOCATING+*(.gnu.linkonce.s.*)}
 330   }
 331   ${RELOCATING+${OTHER_SDATA_SECTIONS}}
 332   ${RELOCATING+_edata = .;}
 333   ${RELOCATING+PROVIDE (edata = .);}
 334   ${RELOCATING+__bss_start = .;}
 335   ${RELOCATING+${OTHER_BSS_SYMBOLS}}
 336   .sbss    ${RELOCATING-0} :
 337   {
 338     ${RELOCATING+PROVIDE (__sbss_start = .);}
 339     ${RELOCATING+PROVIDE (___sbss_start = .);}
 340     *(.dynsbss)
 341     *(.sbss)
 342     ${RELOCATING+*(.sbss.*)}
 343     ${RELOCATING+*(.gnu.linkonce.sb.*)}
 344     *(.scommon)
 345     ${RELOCATING+PROVIDE (__sbss_end = .);}
 346     ${RELOCATING+PROVIDE (___sbss_end = .);}
 347   }
 348   ${BSS_PLT+${PLT}}
 349   .bss     ${RELOCATING-0} :
 350   {
 351    *(.dynbss)
 352    *(.bss)
 353    ${RELOCATING+*(.bss.*)}
 354    ${RELOCATING+*(.gnu.linkonce.b.*)}
 355    *(COMMON)
 356    /* Align here to ensure that the .bss section occupies space up to
 357       _end.  Align after .bss to ensure correct alignment even if the
 358       .bss section disappears because there are no input sections.  */
 359    ${RELOCATING+. = ALIGN(${ALIGNMENT});}
 360   }
 361   ${RELOCATING+${OTHER_BSS_SECTIONS}}
 362   ${RELOCATING+. = ALIGN(${ALIGNMENT});}
 363   ${RELOCATING+_end = .;}
 364   ${RELOCATING+${OTHER_BSS_END_SYMBOLS}}
 365   ${RELOCATING+PROVIDE (end = .);}
 366
 367   /* Stabs debugging sections.  */
 368   .stab 0 : { *(.stab) }
 369   .stabstr 0 : { *(.stabstr) }
 370   .stab.excl 0 : { *(.stab.excl) }
 371   .stab.exclstr 0 : { *(.stab.exclstr) }
 372   .stab.index 0 : { *(.stab.index) }
 373   .stab.indexstr 0 : { *(.stab.indexstr) }
 374
 375   .comment 0 : { *(.comment) }
 376
 377   /* DWARF debug sections.
 378      Symbols in the DWARF debugging sections are relative to the beginning
 379      of the section so we begin them at 0.  */
 380
 381   /* DWARF 1 */
 382   .debug          0 : { *(.debug) }
 383   .line           0 : { *(.line) }
 384
 385   /* GNU DWARF 1 extensions */
 386   .debug_srcinfo  0 : { *(.debug_srcinfo) }
 387   .debug_sfnames  0 : { *(.debug_sfnames) }
 388
 389   /* DWARF 1.1 and DWARF 2 */
 390   .debug_aranges  0 : { *(.debug_aranges) }
 391   .debug_pubnames 0 : { *(.debug_pubnames) }
 392
 393   /* DWARF 2 */
 394   .debug_info     0 : { *(.debug_info) *(.gnu.linkonce.wi.*) }
 395   .debug_abbrev   0 : { *(.debug_abbrev) }
 396   .debug_line     0 : { *(.debug_line) }
 397   .debug_frame    0 : { *(.debug_frame) }
 398   .debug_str      0 : { *(.debug_str) }
 399   .debug_loc      0 : { *(.debug_loc) }
 400   .debug_macinfo  0 : { *(.debug_macinfo) }
 401
 402   /* SGI/MIPS DWARF 2 extensions */
 403   .debug_weaknames 0 : { *(.debug_weaknames) }
 404   .debug_funcnames 0 : { *(.debug_funcnames) }
 405   .debug_typenames 0 : { *(.debug_typenames) }
 406   .debug_varnames  0 : { *(.debug_varnames) }
 407
 408   ${RELOCATING+${OTHER_RELOCATING_SECTIONS}}
 409
 410   /* These must appear regardless of ${RELOCATING}.  */
 411   ${OTHER_SECTIONS}
 412 }
 413 EOF