210949a221
Summary: This should address remaining issues discussed in PR36555. Currently R_GOT*_FROM_END are exclusively used by x86 and x86_64 to express relocations types relative to the GOT base. We have _GLOBAL_OFFSET_TABLE_ (GOT base) = start(.got.plt) but end(.got) != start(.got.plt) This can have problems when _GLOBAL_OFFSET_TABLE_ is used as a symbol, e.g. glibc dl_machine_dynamic assumes _GLOBAL_OFFSET_TABLE_ is start(.got.plt), which is not true. extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden; return _GLOBAL_OFFSET_TABLE_[0]; // R_X86_64_GOTPC32 In this patch, we * Change all GOT*_FROM_END to GOTPLT* to fix the problem. * Add HasGotPltOffRel to denote whether .got.plt should be kept even if the section is empty. * Simplify GotSection::empty and GotPltSection::empty by setting HasGotOffRel and HasGotPltOffRel according to GlobalOffsetTable early. The change of R_386_GOTPC makes X86::writePltHeader simpler as we don't have to compute the offset start(.got.plt) - Ebx (it is constant 0). We still diverge from ld.bfd (at least in most cases) and gold in that .got.plt and .got are not adjacent, but the advantage doing that is unclear. Reviewers: ruiu, sivachandra, espindola Subscribers: emaste, mehdi_amini, arichardson, dexonsmith, jdoerfert, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59594 llvm-svn: 356968
142 lines
3.6 KiB
ArmAsm
142 lines
3.6 KiB
ArmAsm
// REQUIRES: x86
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// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t
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// RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/shared.s -o %t2
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// RUN: ld.lld %t2 -soname fixed-length-string.so -o %t2.so -shared
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// RUN: ld.lld --hash-style=sysv %t %t2.so -o %t3
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// RUN: llvm-readobj -s %t3 | FileCheck --check-prefix=SEC %s
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// RUN: llvm-objdump -s -d %t3 | FileCheck %s
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// SEC: Name: .plt
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// SEC-NEXT: Type: SHT_PROGBITS
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// SEC-NEXT: Flags [
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// SEC-NEXT: SHF_ALLOC
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// SEC-NEXT: SHF_EXECINSTR
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// SEC-NEXT: ]
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// SEC-NEXT: Address: 0x201030
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// SEC-NEXT: Offset: 0x1030
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// SEC-NEXT: Size: 48
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// SEC: Name: .got
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// SEC-NEXT: Type: SHT_PROGBITS
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// SEC-NEXT: Flags [
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// SEC-NEXT: SHF_ALLOC
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// SEC-NEXT: SHF_WRITE
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// SEC-NEXT: ]
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// SEC-NEXT: Address: 0x2020F0
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// SEC-NEXT: Offset:
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// SEC-NEXT: Size: 8
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// SEC-NEXT: Link: 0
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// SEC-NEXT: Info: 0
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// SEC-NEXT: AddressAlignment: 8
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// SEC-NEXT: EntrySize: 0
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// SEC-NEXT: }
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// SEC: Name: .got.plt
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// SEC-NEXT: Type: SHT_PROGBITS
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// SEC-NEXT: Flags [
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// SEC-NEXT: SHF_ALLOC
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// SEC-NEXT: SHF_WRITE
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// SEC-NEXT: ]
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// SEC-NEXT: Address: 0x203000
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// SEC-NEXT: Offset: 0x3000
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// SEC-NEXT: Size: 40
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// SEC-NEXT: Link: 0
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// SEC-NEXT: Info: 0
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// SEC-NEXT: AddressAlignment: 8
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// SEC-NEXT: EntrySize: 0
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// SEC-NEXT: }
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.section .text,"ax",@progbits,unique,1
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.global _start
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_start:
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call lulz
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.section .text,"ax",@progbits,unique,2
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.zero 4
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.global lulz
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lulz:
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nop
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// CHECK: Disassembly of section .text:
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// CHECK-NEXT: _start:
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// CHECK-NEXT: 201000: e8 04 00 00 00 callq 4
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// CHECK-NEXT: 201005:
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// CHECK: lulz:
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// CHECK-NEXT: 201009: 90 nop
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.section .text2,"ax",@progbits
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.global R_X86_64_32
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R_X86_64_32:
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movl $R_X86_64_32, %edx
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// FIXME: this would be far more self evident if llvm-objdump printed
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// constants in hex.
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// CHECK: Disassembly of section .text2:
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// CHECK-NEXT: R_X86_64_32:
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// CHECK-NEXT: 20100a: {{.*}} movl $2101258, %edx
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.section .R_X86_64_32S,"ax",@progbits
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.global R_X86_64_32S
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R_X86_64_32S:
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movq lulz - 0x100000, %rdx
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// CHECK: Disassembly of section .R_X86_64_32S:
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// CHECK-NEXT: R_X86_64_32S:
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// CHECK-NEXT: {{.*}}: {{.*}} movq 1052681, %rdx
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.section .R_X86_64_PC32,"ax",@progbits
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.global R_X86_64_PC32
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R_X86_64_PC32:
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call bar
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movl $bar, %eax
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//16 is a size of PLT[0]
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// 0x201030 + 16 - (0x201017 + 5) = 20
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// CHECK: Disassembly of section .R_X86_64_PC32:
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// CHECK-NEXT: R_X86_64_PC32:
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// CHECK-NEXT: 201017: {{.*}} callq 36
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// CHECK-NEXT: 20101c: {{.*}} movl $2101312, %eax
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.section .R_X86_64_32S_2,"ax",@progbits
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.global R_X86_64_32S_2
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R_X86_64_32S_2:
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mov bar2, %eax
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// plt is at 0x201030. The second plt entry is at 0x201050 == 69712
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// CHECK: Disassembly of section .R_X86_64_32S_2:
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// CHECK-NEXT: R_X86_64_32S_2:
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// CHECK-NEXT: 201021: {{.*}} movl 2101328, %eax
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.section .R_X86_64_64,"a",@progbits
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.global R_X86_64_64
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R_X86_64_64:
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.quad R_X86_64_64
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// CHECK: Contents of section .R_X86_64_64:
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// CHECK-NEXT: 2002f8 f8022000 00000000
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.section .R_X86_64_GOTPCREL,"a",@progbits
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.global R_X86_64_GOTPCREL
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R_X86_64_GOTPCREL:
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.long zed@gotpcrel
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// 0x2020F0(.got) - 0x2002c8(.R_X86_64_GOTPCREL) = 0x1e28
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// CHECK: Contents of section .R_X86_64_GOTPCREL
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// CHECK-NEXT: 200300 f01d0000
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.section .R_X86_64_GOT32,"a",@progbits
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.global R_X86_64_GOT32
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R_X86_64_GOT32:
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.long zed@got
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// CHECK: Contents of section .R_X86_64_GOT32:
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// CHECK-NEXT: f0f0ffff
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// CHECK: Contents of section .R_X86_64_GOT64:
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// CHECK-NEXT: f0f0ffff ffffffff
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.section .R_X86_64_GOT64,"a",@progbits
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.global R_X86_64_GOT64
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R_X86_64_GOT64:
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.quad zed@got
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