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llvm-project/lld/test/ELF/gnu-ifunc-canon.s

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ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// REQUIRES: x86
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %S/Inputs/gnu-ifunc-canon-ro-pcrel.s -o %t-ro-pcrel.o
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %S/Inputs/gnu-ifunc-canon-ro-abs.s -o %t-ro-abs.o
// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %S/Inputs/gnu-ifunc-canon-rw-addend.s -o %t-rw-addend.o
// RUN: ld.lld %t.o -o %t1
[ELF] Don't special case symbolic relocations with 0 addend to ifunc in writable locations Currently the following 3 relocation types do not trigger the creation of a canonical PLT (which changes STT_GNU_IFUNC to STT_FUNC and redirects all references): 1) GOT-generating (`needsGot`) 2) PLT-generating (`needsPlt`) 3) R_ABS with 0 addend in a writable location. This is used for for ifunc function pointers in writable sections such as .data and .toc. This patch deletes case 3) to simplify the R_*_IRELATIVE generating logic added in D57371. Other advantages: * It is guaranteed no more than 1 R_*_IRELATIVE is created for an ifunc. * PPC64: no need to special case ifunc in toc-indirect to toc-relative relaxation. See D65755 The deleted elf::addIRelativeRelocs demonstrates that one-pass scan through relocations makes several optimizations difficult. This is something we can think about in the future. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D65995 llvm-svn: 368661
2019-08-13 17:43:40 +08:00
// RUN: llvm-readobj -r %t1 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o %t-ro-pcrel.o -o %t2
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t2 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o %t-ro-abs.o -o %t3
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t3 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o %t-rw-addend.o -o %t4
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t4 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: llvm-objdump -s %t4 | FileCheck --check-prefix=DUMP %s
// RUN: ld.lld %t.o %t-rw-addend.o -o %t4a -z retpolineplt
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t4a | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: llvm-objdump -s %t4a | FileCheck --check-prefix=DUMP2 %s
// RUN: ld.lld %t-ro-pcrel.o %t.o -o %t5
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t5 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t-ro-abs.o %t.o -o %t6
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t6 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t-rw-addend.o %t.o -o %t7
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t7 | FileCheck --check-prefix=IREL1 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o -o %t8 -pie
[ELF] Don't special case symbolic relocations with 0 addend to ifunc in writable locations Currently the following 3 relocation types do not trigger the creation of a canonical PLT (which changes STT_GNU_IFUNC to STT_FUNC and redirects all references): 1) GOT-generating (`needsGot`) 2) PLT-generating (`needsPlt`) 3) R_ABS with 0 addend in a writable location. This is used for for ifunc function pointers in writable sections such as .data and .toc. This patch deletes case 3) to simplify the R_*_IRELATIVE generating logic added in D57371. Other advantages: * It is guaranteed no more than 1 R_*_IRELATIVE is created for an ifunc. * PPC64: no need to special case ifunc in toc-indirect to toc-relative relaxation. See D65755 The deleted elf::addIRelativeRelocs demonstrates that one-pass scan through relocations makes several optimizations difficult. This is something we can think about in the future. Reviewed By: peter.smith Differential Revision: https://reviews.llvm.org/D65995 llvm-svn: 368661
2019-08-13 17:43:40 +08:00
// RUN: llvm-readobj -r %t8 | FileCheck --check-prefix=IREL1-REL2 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o %t-ro-pcrel.o -o %t9 -pie
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t9 | FileCheck --check-prefix=IREL1-REL2 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t.o %t-rw-addend.o -o %t10 -pie
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t10 | FileCheck --check-prefix=IREL1-REL3 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t-ro-pcrel.o %t.o -o %t11 -pie
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t11 | FileCheck --check-prefix=IREL1-REL2 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// RUN: ld.lld %t-rw-addend.o %t.o -o %t12 -pie
[test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC Also change some options that have different semantics (cause confusion) in llvm-readelf mode: -s => -S -t => --symbols -sd => --section-data llvm-svn: 359651
2019-05-01 13:49:01 +08:00
// RUN: llvm-readobj -r %t12 | FileCheck --check-prefix=IREL1-REL3 %s
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// One reloc for the canonical PLT.
// IREL1-NOT: R_X86_64_
[ELF] Move R_*_IRELATIVE from .rel[a].plt to .rel[a].dyn unless --pack-dyn-relocs=android[+relr] 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
2019-08-03 10:26:52 +08:00
// IREL1: .rela.dyn
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// IREL1-NEXT: R_X86_64_IRELATIVE
// IREL1-NOT: R_X86_64_
// One reloc for the canonical PLT and two RELATIVE relocations pointing to it,
// one in the GOT and one in .data.
// IREL1-REL2-NOT: R_X86_64_
// IREL1-REL2: .rela.dyn
// IREL1-REL2-NEXT: R_X86_64_RELATIVE
// IREL1-REL2-NEXT: R_X86_64_RELATIVE
// IREL1-REL2-NEXT: R_X86_64_IRELATIVE
// IREL1-REL2-NOT: R_X86_64_
// One reloc for the canonical PLT and three RELATIVE relocations pointing to it,
// one in the GOT and two in .data.
// IREL1-REL3-NOT: R_X86_64_
// IREL1-REL3: .rela.dyn
// IREL1-REL3-NEXT: R_X86_64_RELATIVE
// IREL1-REL3-NEXT: R_X86_64_RELATIVE
// IREL1-REL3-NEXT: R_X86_64_RELATIVE
// IREL1-REL3-NEXT: R_X86_64_IRELATIVE
// IREL1-REL3-NOT: R_X86_64_
// Make sure the static relocations look right, both with and without headers.
[ELF] Rename .plt to .iplt and decrease EM_PPC{,64} alignment of .glink to 4 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
2019-12-15 08:19:03 +08:00
// DUMP: Contents of section .iplt:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP-NEXT: 2011f0
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// DUMP: Contents of section .got:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP-NEXT: 202200 f0112000 00000000
[ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss) New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss) The placement of | indicates page alignment caused by PT_GNU_RELRO. The new layout has simpler rules and saves space for many cases. Old size: roundup(.data) + roundup(.data.rel.ro) New size: roundup(.data.rel.ro + .bss.rel.ro) + .data Other advantages: * At runtime the 3 memory mappings decrease to 2. * start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This simplifies binary manipulation tools. GNU strip before 2.31 discards PT_GNU_RELRO if its address is not equal to the start of its associated PT_LOAD. This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f But with this change, we will be compatible with GNU strip before 2.31 * Before, .got.plt (non-relro by default) was placed before .got (relro by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_ (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END) (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we can improve on this regard if we'd like to. Reviewers: ruiu, espindola, pcc Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert Differential Revision: https://reviews.llvm.org/D56828 llvm-svn: 356117
2019-03-14 11:47:45 +08:00
// DUMP: Contents of section .data:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP-NEXT: 203208 f0112000 00000000 f1112000 00000000
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// DUMP2: Contents of section .plt:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP2-NEXT: 2011f0
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
// DUMP2: Contents of section .got:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP2-NEXT: 202240 20122000 00000000
[ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss) New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss) The placement of | indicates page alignment caused by PT_GNU_RELRO. The new layout has simpler rules and saves space for many cases. Old size: roundup(.data) + roundup(.data.rel.ro) New size: roundup(.data.rel.ro + .bss.rel.ro) + .data Other advantages: * At runtime the 3 memory mappings decrease to 2. * start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This simplifies binary manipulation tools. GNU strip before 2.31 discards PT_GNU_RELRO if its address is not equal to the start of its associated PT_LOAD. This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f But with this change, we will be compatible with GNU strip before 2.31 * Before, .got.plt (non-relro by default) was placed before .got (relro by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_ (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END) (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we can improve on this regard if we'd like to. Reviewers: ruiu, espindola, pcc Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert Differential Revision: https://reviews.llvm.org/D56828 llvm-svn: 356117
2019-03-14 11:47:45 +08:00
// DUMP2: Contents of section .data:
[ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64 Port the D64906 technique to EM_X86_64. Differential Revision: https://reviews.llvm.org/D67482 llvm-svn: 371958
2019-09-16 15:05:34 +08:00
// DUMP2-NEXT: 203248 20122000 00000000 21122000 00000000
ELF: Allow GOT relocs pointing to non-preemptable ifunc to resolve to an IRELATIVE where possible. Non-GOT non-PLT relocations to non-preemptible ifuncs result in the creation of a canonical PLT, which now takes the identity of the IFUNC in the symbol table. This (a) ensures address consistency inside and outside the module, and (b) fixes a bug where some of these relocations end up pointing to the resolver. Fixes (at least) PR40474 and PR40501. Differential Revision: https://reviews.llvm.org/D57371 llvm-svn: 353981
2019-02-14 05:49:55 +08:00
lea ifunc@gotpcrel(%rip), %rbx
.type ifunc STT_GNU_IFUNC
.globl ifunc
ifunc:
ret
.data
.8byte ifunc