31ddb15694
Add a new script operator, PROVIDE, to define a symbol only if it is needed. * ldgram.y (PROVIDE): New token. (assignment): Accept PROVIDE. * ldlex.l (PROVIDE): New token. * ldexp.h (node_type): Add etree_provide to node_class enum. (exp_provide): Declare. * ldexp.c (exp_fold_tree): Handle etree_provide. (exp_provide): New function. (exp_print_tree): Handle etree_provide. * ld.texinfo: Document PROVIDE.
105 lines
3.8 KiB
Scala
105 lines
3.8 KiB
Scala
#
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# Unusual variables checked by this code:
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# NOP - two byte opcode for no-op (defaults to 0)
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# DATA_ADDR - if end-of-text-plus-one-page isn't right for data start
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# OTHER_READONLY_SECTIONS - other than .text .init .ctors .rodata ...
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# (e.g., .PARISC.milli)
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# OTHER_READWRITE_SECTIONS - other than .data .bss .sdata ...
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# (e.g., .PARISC.global)
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# OTHER_SECTIONS - at the end
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# EXECUTABLE_SYMBOLS - symbols that must be defined for an
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# executable (e.g., _DYNAMIC_LINK)
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# TEXT_START_SYMBOLS - symbols that appear at the start of the
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# .text section.
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# DATA_START_SYMBOLS - symbols that appear at the start of the
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# .data section.
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# OTHER_BSS_SYMBOLS - symbols that appear at the start of the
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# .bss section besides __bss_start.
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# DATA_PLT - .plt should be in data segment, not text segment.
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#
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# When adding sections, do note that the names of some sections are used
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# when specifying the start address of the next.
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#
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INTERP=".interp ${RELOCATING-0} : { *(.interp) }"
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PLT=".plt ${RELOCATING-0} : { *(.plt) }"
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cat <<EOF
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OUTPUT_FORMAT("${OUTPUT_FORMAT}")
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OUTPUT_ARCH(${ARCH})
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${RELOCATING+${LIB_SEARCH_DIRS}}
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${RELOCATING+/* Do we need any of these for elf?
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__DYNAMIC = 0; ${STACKZERO+${STACKZERO}} ${SHLIB_PATH+${SHLIB_PATH}} */}
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${RELOCATING+${EXECUTABLE_SYMBOLS}}
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${RELOCATING- /* For some reason, the Solaris linker makes bad executables
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if gld -r is used and the intermediate file has sections starting
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at non-zero addresses. Could be a Solaris ld bug, could be a GNU ld
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bug. But for now assigning the zero vmas works. */}
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SECTIONS
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{
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/* Read-only sections, merged into text segment: */
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${CREATE_SHLIB-${RELOCATING+. = ${TEXT_START_ADDR} + SIZEOF_HEADERS;}}
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${CREATE_SHLIB+${RELOCATING+. = SIZEOF_HEADERS;}}
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${CREATE_SHLIB-${INTERP}}
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.hash ${RELOCATING-0} : { *(.hash) }
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.dynsym ${RELOCATING-0} : { *(.dynsym) }
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.dynstr ${RELOCATING-0} : { *(.dynstr) }
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.rel.bss ${RELOCATING-0} : { *(.rel.bss) }
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.rel.plt ${RELOCATING-0} : { *(.rel.plt) }
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.rela.bss ${RELOCATING-0} : { *(.rela.bss) }
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.rela.plt ${RELOCATING-0} : { *(.rela.plt) }
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.init ${RELOCATING-0} : { *(.init) } =${NOP-0}
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${DATA_PLT-${PLT}}
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.text ${RELOCATING-0} :
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{
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${RELOCATING+${TEXT_START_SYMBOLS}}
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*(.text)
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}
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${RELOCATING+_etext = .;}
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${RELOCATING+PROVIDE (etext = .);}
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.fini ${RELOCATING-0} : { *(.fini) } =${NOP-0}
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.ctors ${RELOCATING-0} : { *(.ctors) }
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.dtors ${RELOCATING-0} : { *(.dtors) }
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.rodata ${RELOCATING-0} : { *(.rodata) }
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.rodata1 ${RELOCATING-0} : { *(.rodata1) }
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${RELOCATING+${OTHER_READONLY_SECTIONS}}
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/* Read-write section, merged into data segment: */
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${RELOCATING+. = ${DATA_ADDR- ALIGN(8) + ${MAXPAGESIZE}};}
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.data ${RELOCATING-0} :
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{
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${RELOCATING+${DATA_START_SYMBOLS}}
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*(.data)
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${CONSTRUCTING+CONSTRUCTORS}
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}
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.data1 ${RELOCATING-0} : { *(.data1) }
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${RELOCATING+${OTHER_READWRITE_SECTIONS}}
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.got ${RELOCATING-0} : { *(.got) }
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.dynamic ${RELOCATING-0} : { *(.dynamic) }
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${DATA_PLT+${PLT}}
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/* We want the small data sections together, so single-instruction offsets
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can access them all, and initialized data all before uninitialized, so
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we can shorten the on-disk segment size. */
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.sdata ${RELOCATING-0} : { *(.sdata) }
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${RELOCATING+_edata = .;}
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${RELOCATING+PROVIDE (edata = .);}
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${RELOCATING+__bss_start = .;}
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${RELOCATING+${OTHER_BSS_SYMBOLS}}
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.sbss ${RELOCATING-0} : { *(.sbss) *(.scommon) }
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.bss ${RELOCATING-0} :
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{
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*(.dynbss)
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*(.bss)
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*(COMMON)
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}
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${RELOCATING+_end = . ;}
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${RELOCATING+PROVIDE (end = .);}
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/* These are needed for ELF backends which have not yet been
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converted to the new style linker. */
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.stab 0 : { *(.stab) }
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.stabstr 0 : { *(.stabstr) }
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/* These must appear regardless of ${RELOCATING}. */
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${OTHER_SECTIONS}
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}
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EOF
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