2018-06-27 06:20:04 +08:00
|
|
|
// REQUIRES: arm
|
2019-03-28 19:10:20 +08:00
|
|
|
// RUN: llvm-mc -filetype=obj -arm-add-build-attributes -triple=armv7a-none-linux-gnueabi %s -o %t
|
2019-07-22 19:37:03 +08:00
|
|
|
// RUN: ld.lld --hash-style=sysv %t --shared -o %t2
|
2016-10-20 17:59:26 +08:00
|
|
|
// RUN: llvm-readobj --relocations %t2 | FileCheck %s
|
2019-03-28 19:10:20 +08:00
|
|
|
// RUN: llvm-objdump -s -triple=armv7a-none-linux-gnueabi %t2 | FileCheck --check-prefix=CHECK-EXTAB-NEXT %s
|
2016-10-20 17:59:26 +08:00
|
|
|
|
|
|
|
|
// Check that the relative R_ARM_PREL31 relocation can access a PLT entry
|
|
|
|
|
// for when the personality routine is referenced from a shared library.
|
|
|
|
|
// Also check that the R_ARM_NONE no-op relocation can be used in a shared
|
|
|
|
|
// library.
|
|
|
|
|
.syntax unified
|
|
|
|
|
// Will produce an ARM.exidx entry with an R_ARM_NONE relocation to
|
|
|
|
|
// __aeabi_unwind_cpp_pr0
|
|
|
|
|
.section .text.func1, "ax",%progbits
|
|
|
|
|
.global func1
|
|
|
|
|
func1:
|
|
|
|
|
.fnstart
|
|
|
|
|
bx lr
|
|
|
|
|
.fnend
|
|
|
|
|
|
|
|
|
|
// Will produce a R_ARM_PREL31 relocation with respect to the PLT entry of
|
|
|
|
|
// __gxx_personality_v0
|
|
|
|
|
.section .text.func2, "ax",%progbits
|
|
|
|
|
.global func2
|
|
|
|
|
func2:
|
|
|
|
|
.fnstart
|
|
|
|
|
bx lr
|
|
|
|
|
.personality __gxx_personality_v0
|
|
|
|
|
.handlerdata
|
|
|
|
|
.long 0
|
|
|
|
|
.section .text.func2
|
|
|
|
|
.fnend
|
|
|
|
|
|
|
|
|
|
.section .text.__aeabi_unwind_cpp_pr0, "ax", %progbits
|
|
|
|
|
.global __aeabi_unwind_cpp_pr0
|
|
|
|
|
__aeabi_unwind_cpp_pr0:
|
|
|
|
|
bx lr
|
|
|
|
|
|
|
|
|
|
// CHECK: Relocations [
|
2018-06-27 06:13:32 +08:00
|
|
|
// CHECK-NEXT: Section {{.*}} .rel.plt {
|
[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
|
|
|
// CHECK-NEXT: 0x300C R_ARM_JUMP_SLOT __gxx_personality_v0
|
2016-10-20 17:59:26 +08:00
|
|
|
|
2017-06-28 17:12:38 +08:00
|
|
|
// CHECK-EXTAB: Contents of section .ARM.extab:
|
2019-03-28 19:10:20 +08:00
|
|
|
// 0x0238 + 0xdf8 = 0x1030 = __gxx_personality_v0(PLT)
|
|
|
|
|
// CHECK-EXTAB-NEXT: 0238 f80d0000 b0b0b000 00000000
|