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80070c0d34
Complement commit902e9fc76a("PR ld/20828: Move symbol version processing ahead of GC symbol sweep"), commitb531344c34("PR ld/20828: Reorder the symbol sweep stage of section GC") and commit81ff47b3a5("PR ld/20828: Fix linker script symbols wrongly forced local with section GC"), and prevent symbols forcibly entered in the output file with the use of the `--undefined=' or `--require-defined=' linker command line options or the EXTERN linker script command from being swept in section garbage collection and consequently recorded in the dynamic symbol table as local entries. This happens in certain circumstances, where a symbol reference also exists in one of the static input files, however only in a section which is garbage-collected and does not make it to the output file, and the symbol is defined in a dynamic object present in the link. For example with the `i386-linux' target and the `pr21233.s' and `pr21233-l.s' sources, and the `pr21233.ld' linker script included with this change we get: $ as -o pr21233-l.o pr21233-l.s $ ld -shared -T pr21233.ld -o libpr21233.so pr21233-l.o $ as -o pr21233.o pr21233.s $ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so $ readelf --dyn-syms pr21233 Symbol table '.dynsym' contains 2 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00000000 0 OBJECT LOCAL DEFAULT UND bar $ which makes the run-time `bar' dependency of the `pr21233' executable different from its corresponding link-time dependency, i.e. the presence of `libpr21233.so' and its `bar' symbol is required at the link time, however at the run time a copy of `libpr21233.so' without `bar' will do. Similarly with `--undefined=' and EXTERN which do not actually require the reference to the symbol requested to be satisfied with a definition at the link time, however once the definition has been pulled at the link time, so it should at the dynamic load time. Additionally with the `mips-linux' target we get: $ ld --gc-sections -e foo --require-defined=bar -T pr21233.ld -o pr21233 pr21233.o libpr21233.so ld: BFD (GNU Binutils) 2.28.51.20170324 assertion fail .../bfd/elfxx-mips.c:3861 $ as the target is not prepared to handle such a local dynamic symbol. With this change in effect we get: $ readelf --dyn-syms pr21233 Symbol table '.dynsym' contains 2 entries: Num: Value Size Type Bind Vis Ndx Name 0: 00000000 0 NOTYPE LOCAL DEFAULT UND 1: 00000000 0 OBJECT GLOBAL DEFAULT UND bar $ instead, for both targets. ld/ PR ld/21233 * ldlang.c (insert_undefined): Set `mark' for ELF symbols. * testsuite/ld-elf/pr21233.sd: New test. * testsuite/ld-elf/pr21233-l.sd: New test. * testsuite/ld-elf/pr21233.ld: New test linker script. * testsuite/ld-elf/pr21233-e.ld: New test linker script. * testsuite/ld-elf/pr21233.s: New test source. * testsuite/ld-elf/pr21233-l.s: New test source. * testsuite/ld-elf/shared.exp: Run the new tests.
18 lines
373 B
Plaintext
18 lines
373 B
Plaintext
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