ld/scripttempl/elf_chaos.sc

   1 # Copyright (C) 2014-2023 Free Software Foundation, Inc.
   2 #
   3 # Copying and distribution of this file, with or without modification,
   4 # are permitted in any medium without royalty provided the copyright
   5 # notice and this notice are preserved.
   6 #
   7 # Unusual variables checked by this code:
   8 #       NOP - four byte opcode for no-op (defaults to 0)
   9 #       NO_SMALL_DATA - no .sbss/.sbss2/.sdata/.sdata2 sections if not
  10 #               empty.
  11 #       DATA_ADDR - if end-of-text-plus-one-page isn't right for data start
  12 #       INITIAL_READONLY_SECTIONS - at start of text segment
  13 #       OTHER_READONLY_SECTIONS - other than .text .init .rodata ...
  14 #               (e.g., .PARISC.milli)
  15 #       OTHER_TEXT_SECTIONS - these get put in .text when relocating
  16 #       OTHER_READWRITE_SECTIONS - other than .data .bss .ctors .sdata ...
  17 #               (e.g., .PARISC.global)
  18 #       ATTRS_SECTIONS - at the end
  19 #       OTHER_SECTIONS - at the end
  20 #       EXECUTABLE_SYMBOLS - symbols that must be defined for an
  21 #               executable (e.g., _DYNAMIC_LINK)
  22 #       TEXT_START_SYMBOLS - symbols that appear at the start of the
  23 #               .text section.
  24 #       DATA_START_SYMBOLS - symbols that appear at the start of the
  25 #               .data section.
  26 #       OTHER_GOT_SYMBOLS - symbols defined just before .got.
  27 #       OTHER_GOT_SECTIONS - sections just after .got.
  28 #       OTHER_SDATA_SECTIONS - sections just after .sdata.
  29 #       OTHER_BSS_SYMBOLS - symbols that appear at the start of the
  30 #               .bss section besides __bss_start.
  31 #       DATA_PLT - .plt should be in data segment, not text segment.
  32 #       BSS_PLT - .plt should be in bss segment
  33 #       TEXT_DYNAMIC - .dynamic in text segment, not data segment.
  34 #       EMBEDDED - whether this is for an embedded system.
  35 #       SHLIB_TEXT_START_ADDR - if set, add to SIZEOF_HEADERS to set
  36 #               start address of shared library.
  37 #       INPUT_FILES - INPUT command of files to always include
  38 #       WRITABLE_RODATA - if set, the .rodata section should be writable
  39 #       INIT_START, INIT_END -  statements just before and just after
  40 #       combination of .init sections.
  41 #       FINI_START, FINI_END - statements just before and just after
  42 #       combination of .fini sections.
  43 #       STACK_ADDR - start of a .stack section.
  44 #       OTHER_SYMBOLS - symbols to place right at the end of the script.
  45 #
  46 # When adding sections, do note that the names of some sections are used
  47 # when specifying the start address of the next.
  48 #
  49
  50 #  Many sections come in three flavours.  There is the 'real' section,
  51 #  like ".data".  Then there are the per-procedure or per-variable
  52 #  sections, generated by -ffunction-sections and -fdata-sections in GCC,
  53 #  and useful for --gc-sections, which for a variable "foo" might be
  54 #  ".data.foo".  Then there are the linkonce sections, for which the linker
  55 #  eliminates duplicates, which are named like ".gnu.linkonce.d.foo".
  56 #  The exact correspondences are:
  57 #
  58 #  Section      Linkonce section
  59 #  .text        .gnu.linkonce.t.foo
  60 #  .rodata      .gnu.linkonce.r.foo
  61 #  .data        .gnu.linkonce.d.foo
  62 #  .bss         .gnu.linkonce.b.foo
  63 #  .sdata       .gnu.linkonce.s.foo
  64 #  .sbss        .gnu.linkonce.sb.foo
  65 #  .sdata2      .gnu.linkonce.s2.foo
  66 #  .sbss2       .gnu.linkonce.sb2.foo
  67 #  .debug_info  .gnu.linkonce.wi.foo
  68 #
  69 #  Each of these can also have corresponding .rel.* and .rela.* sections.
  70
  71 test -z "$ENTRY" && ENTRY=_start
  72 test -z "${BIG_OUTPUT_FORMAT}" && BIG_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  73 test -z "${LITTLE_OUTPUT_FORMAT}" && LITTLE_OUTPUT_FORMAT=${OUTPUT_FORMAT}
  74 if [ -z "$MACHINE" ]; then OUTPUT_ARCH=${ARCH}; else OUTPUT_ARCH=${ARCH}:${MACHINE}; fi
  75 test -z "${ELFSIZE}" && ELFSIZE=32
  76 test -z "${ALIGNMENT}" && ALIGNMENT="${ELFSIZE} / 8"
  77 test -z "$ATTRS_SECTIONS" && ATTRS_SECTIONS=".gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }"
  78 test "$LD_FLAG" = "N" && DATA_ADDR=.
  79 INTERP=".interp       ${RELOCATING-0} : { *(.interp) }"
  80 PLT=".plt          ${RELOCATING-0} : { *(.plt) }"
  81 DYNAMIC=".dynamic      ${RELOCATING-0} : { *(.dynamic) }"
  82 RODATA=".rodata       ${RELOCATING-0} : { *(.rodata${RELOCATING+ .rodata.* .gnu.linkonce.r.*}) }"
  83 if test -z "${NO_SMALL_DATA}"; then
  84   SBSS=".sbss         ${RELOCATING-0} :
  85   {
  86     ${RELOCATING+PROVIDE (__sbss_start = .);}
  87     ${RELOCATING+PROVIDE (___sbss_start = .);}
  88     *(.dynsbss)
  89     *(.sbss${RELOCATING+ .sbss.* .gnu.linkonce.sb.*})
  90     *(.scommon)
  91     ${RELOCATING+PROVIDE (__sbss_end = .);}
  92     ${RELOCATING+PROVIDE (___sbss_end = .);}
  93   }"
  94   SBSS2=".sbss2        ${RELOCATING-0} : { *(.sbss2${RELOCATING+ .sbss2.* .gnu.linkonce.sb2.*}) }"
  95   SDATA="/* We want the small data sections together, so single-instruction offsets
  96      can access them all, and initialized data all before uninitialized, so
  97      we can shorten the on-disk segment size.  */
  98   .sdata        ${RELOCATING-0} :
  99   {
 100     ${RELOCATING+${SDATA_START_SYMBOLS}}
 101     *(.sdata${RELOCATING+ .sdata.* .gnu.linkonce.s.*})
 102   }"
 103   SDATA2=".sdata2       ${RELOCATING-0} : { *(.sdata2${RELOCATING+ .sdata2.* .gnu.linkonce.s2.*}) }"
 104   REL_SDATA=".rel.sdata    ${RELOCATING-0} : { *(.rel.sdata${RELOCATING+ .rel.sdata.* .rel.gnu.linkonce.s.*}) }
 105   .rela.sdata   ${RELOCATING-0} : { *(.rela.sdata${RELOCATING+ .rela.sdata.* .rela.gnu.linkonce.s.*}) }"
 106   REL_SBSS=".rel.sbss     ${RELOCATING-0} : { *(.rel.sbss${RELOCATING+ .rel.sbss.* .rel.gnu.linkonce.sb.*}) }
 107   .rela.sbss    ${RELOCATING-0} : { *(.rela.sbss${RELOCATING+ .rela.sbss.* .rela.gnu.linkonce.sb.*}) }"
 108   REL_SDATA2=".rel.sdata2   ${RELOCATING-0} : { *(.rel.sdata2${RELOCATING+ .rel.sdata2.* .rel.gnu.linkonce.s2.*}) }
 109   .rela.sdata2  ${RELOCATING-0} : { *(.rela.sdata2${RELOCATING+ .rela.sdata2.* .rela.gnu.linkonce.s2.*}) }"
 110   REL_SBSS2=".rel.sbss2    ${RELOCATING-0} : { *(.rel.sbss2${RELOCATING+ .rel.sbss2.* .rel.gnu.linkonce.sb2.*}) }
 111   .rela.sbss2   ${RELOCATING-0} : { *(.rela.sbss2${RELOCATING+ .rela.sbss2.* .rela.gnu.linkonce.sb2.*}) }"
 112 fi
 113 CTOR="
 114     ${CONSTRUCTING+${CTOR_START}}
 115     /* gcc uses crtbegin.o to find the start of
 116        the constructors, so we make sure it is
 117        first.  Because this is a wildcard, it
 118        doesn't matter if the user does not
 119        actually link against crtbegin.o; the
 120        linker won't look for a file to match a
 121        wildcard.  The wildcard also means that it
 122        doesn't matter which directory crtbegin.o
 123        is in.  */
 124
 125     KEEP (*crtbegin.o(.ctors))
 126     KEEP (*crtbegin?.o(.ctors))
 127
 128     /* We don't want to include the .ctor section from
 129        the crtend.o file until after the sorted ctors.
 130        The .ctor section from the crtend file contains the
 131        end of ctors marker and it must be last */
 132
 133     KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o $OTHER_EXCLUDE_FILES) .ctors))
 134     KEEP (*(SORT(.ctors.*)))
 135     KEEP (*(.ctors))
 136     ${CONSTRUCTING+${CTOR_END}}
 137 "
 138 DTOR="
 139     ${CONSTRUCTING+${DTOR_START}}
 140     KEEP (*crtbegin.o(.dtors))
 141     KEEP (*crtbegin?.o(.dtors))
 142     KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o $OTHER_EXCLUDE_FILES) .dtors))
 143     KEEP (*(SORT(.dtors.*)))
 144     KEEP (*(.dtors))
 145     ${CONSTRUCTING+${DTOR_END}}
 146 "
 147 STACK="  .stack        ${RELOCATING-0}${RELOCATING+${STACK_ADDR}} :
 148   {
 149     ${RELOCATING+_stack = .;}
 150     *(.stack)
 151   }"
 152
 153 test -z "${TEXT_BASE_ADDRESS}" && TEXT_BASE_ADDRESS="${TEXT_START_ADDR}"
 154
 155 cat <<EOF
 156 /* Copyright (C) 2014-2023 Free Software Foundation, Inc.
 157
 158    Copying and distribution of this script, with or without modification,
 159    are permitted in any medium without royalty provided the copyright
 160    notice and this notice are preserved.  */
 161
 162 OUTPUT_FORMAT("${OUTPUT_FORMAT}", "${BIG_OUTPUT_FORMAT}",
 163               "${LITTLE_OUTPUT_FORMAT}")
 164 OUTPUT_ARCH(${OUTPUT_ARCH})
 165 ${RELOCATING+ENTRY(${ENTRY})}
 166
 167 ${RELOCATING+${LIB_SEARCH_DIRS}}
 168 ${RELOCATING+/* Do we need any of these for elf?
 169    __DYNAMIC = 0; ${STACKZERO+${STACKZERO}} ${SHLIB_PATH+${SHLIB_PATH}}  */}
 170 ${RELOCATING+${EXECUTABLE_SYMBOLS}}
 171 ${RELOCATING+${INPUT_FILES}}
 172 ${RELOCATING- /* For some reason, the Solaris linker makes bad executables
 173   if gld -r is used and the intermediate file has sections starting
 174   at non-zero addresses.  Could be a Solaris ld bug, could be a GNU ld
 175   bug.  But for now assigning the zero vmas works.  */}
 176
 177 SECTIONS
 178 {
 179   /* Read-only sections, merged into text segment: */
 180   ${CREATE_SHLIB-${RELOCATING+. = ${TEXT_BASE_ADDRESS};}}
 181   ${CREATE_SHLIB+${RELOCATING+. = ${SHLIB_TEXT_START_ADDR:-0};}}
 182   ${CREATE_SHLIB-${INTERP}}
 183   ${INITIAL_READONLY_SECTIONS}
 184   ${TEXT_DYNAMIC+${DYNAMIC}}
 185   .hash         ${RELOCATING-0} : { *(.hash) }
 186   .dynsym       ${RELOCATING-0} : { *(.dynsym) }
 187   .dynstr       ${RELOCATING-0} : { *(.dynstr) }
 188   .gnu.version  ${RELOCATING-0} : { *(.gnu.version) }
 189   .gnu.version_d ${RELOCATING-0}: { *(.gnu.version_d) }
 190   .gnu.version_r ${RELOCATING-0}: { *(.gnu.version_r) }
 191
 192 EOF
 193 if [ "x$COMBRELOC" = x ]; then
 194   COMBRELOCCAT=cat
 195 else
 196   COMBRELOCCAT="cat > $COMBRELOC"
 197 fi
 198 eval $COMBRELOCCAT <<EOF
 199   .rel.init     ${RELOCATING-0} : { *(.rel.init) }
 200   .rela.init    ${RELOCATING-0} : { *(.rela.init) }
 201   .rel.text     ${RELOCATING-0} : { *(.rel.text${RELOCATING+ .rel.text.* .rel.gnu.linkonce.t.*}) }
 202   .rela.text    ${RELOCATING-0} : { *(.rela.text${RELOCATING+ .rela.text.* .rela.gnu.linkonce.t.*}) }
 203   .rel.fini     ${RELOCATING-0} : { *(.rel.fini) }
 204   .rela.fini    ${RELOCATING-0} : { *(.rela.fini) }
 205   .rel.rodata   ${RELOCATING-0} : { *(.rel.rodata${RELOCATING+ .rel.rodata.* .rel.gnu.linkonce.r.*}) }
 206   .rela.rodata  ${RELOCATING-0} : { *(.rela.rodata${RELOCATING+ .rela.rodata.* .rela.gnu.linkonce.r.*}) }
 207   ${OTHER_READONLY_RELOC_SECTIONS}
 208   .rel.data     ${RELOCATING-0} : { *(.rel.data${RELOCATING+ .rel.data.* .rel.gnu.linkonce.d.*}) }
 209   .rela.data    ${RELOCATING-0} : { *(.rela.data${RELOCATING+ .rela.data.* .rela.gnu.linkonce.d.*}) }
 210   .rel.ctors    ${RELOCATING-0} : { *(.rel.ctors) }
 211   .rela.ctors   ${RELOCATING-0} : { *(.rela.ctors) }
 212   .rel.dtors    ${RELOCATING-0} : { *(.rel.dtors) }
 213   .rela.dtors   ${RELOCATING-0} : { *(.rela.dtors) }
 214   .rel.got      ${RELOCATING-0} : { *(.rel.got) }
 215   .rela.got     ${RELOCATING-0} : { *(.rela.got) }
 216   ${OTHER_GOT_RELOC_SECTIONS}
 217   ${REL_SDATA}
 218   ${REL_SBSS}
 219   ${REL_SDATA2}
 220   ${REL_SBSS2}
 221   .rel.bss      ${RELOCATING-0} : { *(.rel.bss${RELOCATING+ .rel.bss.* .rel.gnu.linkonce.b.*}) }
 222   .rela.bss     ${RELOCATING-0} : { *(.rela.bss${RELOCATING+ .rela.bss.* .rela.gnu.linkonce.b.*}) }
 223 EOF
 224 if [ -n "$COMBRELOC" ]; then
 225 cat <<EOF
 226   .rel.dyn      ${RELOCATING-0} :
 227     {
 228 EOF
 229 sed -e '/^[      ]*[{}][         ]*$/d;/:[       ]*$/d;/\.rela\./d;s/^.*: { *\(.*\)}$/      \1/' $COMBRELOC
 230 cat <<EOF
 231     }
 232   .rela.dyn     ${RELOCATING-0} :
 233     {
 234 EOF
 235 sed -e '/^[      ]*[{}][         ]*$/d;/:[       ]*$/d;/\.rel\./d;s/^.*: { *\(.*\)}/      \1/' $COMBRELOC
 236 cat <<EOF
 237     }
 238 EOF
 239 fi
 240 cat <<EOF
 241   ${RELOCATING+. = ALIGN(0x1000);}
 242   .rel.plt      ${RELOCATING-0} : { *(.rel.plt) }
 243   .rela.plt     ${RELOCATING-0} : { *(.rela.plt) }
 244   ${OTHER_PLT_RELOC_SECTIONS}
 245   ${DATA_PLT-${BSS_PLT-${PLT}}}
 246   .text         ${RELOCATING-0} :
 247   {
 248     ${RELOCATING+${TEXT_START_SYMBOLS}}
 249     *(.text .stub${RELOCATING+ .text.* .gnu.linkonce.t.*})
 250     /* .gnu.warning sections are handled specially by elf.em.  */
 251     *(.gnu.warning)
 252     ${RELOCATING+${OTHER_TEXT_SECTIONS}}
 253   } =${NOP-0}
 254   .init         ${RELOCATING-0} :
 255   {
 256     ${RELOCATING+${INIT_START}}
 257     KEEP (*(SORT_NONE(.init)))
 258     ${RELOCATING+${INIT_END}}
 259   } =${NOP-0}
 260   .fini         ${RELOCATING-0} :
 261   {
 262     ${RELOCATING+${FINI_START}}
 263     KEEP (*(SORT_NONE(.fini)))
 264     ${RELOCATING+${FINI_END}}
 265   } =${NOP-0}
 266   ${RELOCATING+PROVIDE (__etext = .);}
 267   ${RELOCATING+PROVIDE (_etext = .);}
 268   ${RELOCATING+PROVIDE (etext = .);}
 269   ${RELOCATING+. = ALIGN(0x1000);}
 270   ${CREATE_SHLIB-${SDATA2}}
 271   ${CREATE_SHLIB-${SBSS2}}
 272   ${OTHER_READONLY_SECTIONS}
 273   .eh_frame_hdr ${RELOCATING-0} : { *(.eh_frame_hdr) }
 274
 275   ${RELOCATING+. = ALIGN(0x1000);}
 276   .data         ${RELOCATING-0} :
 277   {
 278     ${RELOCATING+*(.rodata .rodata.*)
 279     *(.rodata1)
 280     *(.gnu.linkonce.r.*)
 281     ${DATA_START_SYMBOLS}}
 282     *(.data${RELOCATING+ .data.* .gnu.linkonce.d.*})
 283     ${CONSTRUCTING+SORT(CONSTRUCTORS)}
 284     ${RELOCATING+KEEP (*(.eh_frame))
 285     *(.gcc_except_table)
 286     ${CTOR}
 287     ${DTOR}
 288     KEEP (*(.jcr))}
 289   }
 290   .data1        ${RELOCATING-0} : { *(.data1) }
 291   ${RELOCATING+. = ALIGN(0x1000);}
 292   .gcc_except_table ${RELOCATING-0} : { *(.gcc_except_table) }
 293   ${WRITABLE_RODATA+${RODATA}}
 294   ${OTHER_READWRITE_SECTIONS}
 295   ${TEXT_DYNAMIC-${DYNAMIC}}
 296   ${DATA_PLT+${PLT}}
 297   ${RELOCATING+${OTHER_GOT_SYMBOLS}}
 298   .got          ${RELOCATING-0} : {${RELOCATING+ *(.got.plt)} *(.got) }
 299   ${OTHER_GOT_SECTIONS}
 300   ${CREATE_SHLIB+${SDATA2}}
 301   ${CREATE_SHLIB+${SBSS2}}
 302   ${SDATA}
 303   ${OTHER_SDATA_SECTIONS}
 304   ${RELOCATING+_edata = .;}
 305   ${RELOCATING+PROVIDE (edata = .);}
 306   ${RELOCATING+__bss_start = .;}
 307   ${RELOCATING+${OTHER_BSS_SYMBOLS}}
 308   ${SBSS}
 309   ${BSS_PLT+${PLT}}
 310   ${RELOCATING+. = ALIGN(0x1000);}
 311   .bss          ${RELOCATING-0} :
 312   {
 313    ${RELOCATING+*(.dynbss)}
 314    *(.bss${RELOCATING+ .bss.* .gnu.linkonce.b.*})
 315    ${RELOCATING+*(COMMON)
 316    /* Align here to ensure that the .bss section occupies space up to
 317       _end.  Align after .bss to ensure correct alignment even if the
 318       .bss section disappears because there are no input sections.  */
 319    . = ALIGN(${ALIGNMENT});}
 320   }
 321   ${RELOCATING+${OTHER_BSS_END_SYMBOLS}}
 322   ${RELOCATING+. = ALIGN(${ALIGNMENT});}
 323   ${RELOCATING+${OTHER_END_SYMBOLS}}
 324   ${RELOCATING+_end = .;}
 325   ${RELOCATING+PROVIDE (end = .);}
 326   ${STACK_ADDR+${STACK}}
 327
 328 EOF
 329
 330 source_sh $srcdir/scripttempl/misc-sections.sc
 331 source_sh $srcdir/scripttempl/DWARF.sc
 332
 333 cat <<EOF
 334   ${ATTRS_SECTIONS}
 335   ${OTHER_SECTIONS}
 336   ${RELOCATING+${OTHER_SYMBOLS}}
 337 }
 338 EOF