This behavior matches GNU ld and seems reasonable.
```
// If a SECTIONS command is not specified
.text.* -> .text
.rodata.* -> .rodata
.init_array.* -> .init_array
```
A proposed Linux feature CONFIG_FG_KASLR may depend on the GNU ld behavior.
Reword a comment about -z keep-text-section-prefix and a comment about
CommonSection (deleted by rL286234).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75225
This makes --orphan-handling= less noisy.
This change also improves our compatibility with GNU ld.
GNU ld special cases .symtab, .strtab and .shstrtab . We need output section
descriptions for .symtab, .strtab and .shstrtab to suppress:
<internal>:(.symtab) is being placed in '.symtab'
<internal>:(.shstrtab) is being placed in '.shstrtab'
<internal>:(.strtab) is being placed in '.strtab'
With --strip-all, .symtab and .strtab can be omitted (note, --strip-all is not compatible with --emit-relocs).
Reviewed By: nickdesaulniers
Differential Revision: https://reviews.llvm.org/D75149
GNU ld creates the synthetic section .iplt, and has a built-in linker
script that assigns .iplt to the output section .plt . There is no
output section named .iplt .
Making .iplt an output section actually has a benefit that makes the
tricky toolchain feature stand out. Symbolizers don't have to deal with
mixed PLT entries (e.g. llvm-objdump -d incorrectly annotates such jump
targets).
On EM_PPC{,64}, .glink contains a PLT resolver and a series of jump
instructions. The 4-byte entry size makes it unnecessary to have an
alignment of 16.
Mark ppc32-gnu-ifunc.s and ppc32-gnu-ifunc-nonpreemptable.s as `XFAIL: *`.
They test IPLT on EM_PPC, which never works.
Reviewed By: peter.smith
Differential Revision: https://reviews.llvm.org/D71520
An R_*_IRELATIVE represents the address of a STT_GNU_IFUNC symbol
(redirected at runtime) which is non-preemptable and is not associated
with a canonical PLT (associated with a symbol with a section index of
SHN_UNDEF but a non-zero st_value).
.rel[a].plt [DT_JMPREL, DT_JMPREL+DT_JMPRELSZ) contains relocations that
can be lazily resolved. R_*_IRELATIVE are always eagerly resolved, so
conceptually they do not belong to .rela.plt. "iplt" is mostly a misnomer.
glibc powerpc and powerpc64 do not resolve R_*_IRELATIVE if they are in .rela.plt.
// a.o - synthesized PLT call stub has an R_*_IRELATIVE
void ifunc(); int main() { ifunc(); }
// b.o
static void real() {}
asm (".type ifunc, %gnu_indirect_function");
void *ifunc() { return ℜ }
The lld-linked executable crashes. ld.bfd places R_*_IRELATIVE in
.rela.dyn and the executable works.
glibc i386, x86_64, and aarch64 have logic
(glibc/sysdeps/*/dl-machine.h:elf_machine_lazy_rel) to eagerly resolve
R_*_IRELATIVE in .rel[a].plt so the lld-linked executable works.
Move R_*_IRELATIVE from .rel[a].plt to .rel[a].dyn to fix the crashes on
glibc powerpc/powerpc64. This also helps simplifying ifunc
implementation in FreeBSD rtld-elf powerpc64.
If --pack-dyn-relocs=android[+relr] is specified, the Android packed
dynamic relocation format is used for .rela.dyn. We cannot name
in.relaIplt ".rela.dyn" because the output section will have mixed
formats. This can be improved in the future.
Reviewed By: pcc
Differential Revision: https://reviews.llvm.org/D65651
llvm-svn: 367745
We create several types of synthetic sections for loadable partitions, including:
- The dynamic symbol table. This allows code outside of the loadable partitions
to find entry points with dlsym.
- Creating a dynamic symbol table also requires the creation of several other
synthetic sections for the partition, such as the dynamic table and hash table
sections.
- The partition's ELF header is represented as a synthetic section in the
combined output file, and will be used by llvm-objcopy to extract partitions.
Differential Revision: https://reviews.llvm.org/D62350
llvm-svn: 362819
The typo was introduced to llvm MC in rL204769 (fixed in rL358247) and then to lld.
Also, for relocatable-many-sections.s, the size of .symtab changed at some point and the formula needs update.
llvm-svn: 358248
It is PR34946.
Spec (http://man7.org/linux/man-pages/man1/ld.1.html) tells about
--orphan-handling=MODE, option where MODE can be one of four:
"place", "discard", "warn", "error".
Currently we already report orphans when -verbose given,
what becomes excessive with option implemented.
Patch stops reporting orphans when -versbose is given,
and support "place", "warn" and "error" modes.
It is not yet clear that "discard" mode is useful so it is not supported.
Differential revision: https://reviews.llvm.org/D39000
llvm-svn: 316583
Its PR34712,
GNU linkers recently changed default values to "both" of "sysv".
Patch do the same for all targets except MIPS, where .gnu.hash
section is not yet supported.
Code suggested by Rui Ueyama.
Differential revision: https://reviews.llvm.org/D38407
llvm-svn: 315051
When -verbose is specified, patch outputs names of each input orphan section
assigned to output.
Differential revision: https://reviews.llvm.org/D37517
llvm-svn: 314098
Fangrui Song