07f8daf05e
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
83 lines
2.5 KiB
ArmAsm
83 lines
2.5 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: ld.lld %t -o %t2 -shared --apply-dynamic-relocs
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// RUN: llvm-readobj -s -section-data -r %t2 | FileCheck -check-prefix CHECK -check-prefix APPLYDYNREL %s
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// RUN: ld.lld %t -o %t2 -shared
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// RUN: llvm-readobj -s -section-data -r %t2 | FileCheck -check-prefix CHECK -check-prefix NOAPPLYDYNREL %s
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// RUN: ld.lld %t -o %t2 -shared --no-apply-dynamic-relocs
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// RUN: llvm-readobj -s -section-data -r %t2 | FileCheck -check-prefix CHECK -check-prefix NOAPPLYDYNREL %s
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// APPLYDYNREL: Name: .data
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// APPLYDYNREL-NEXT: Type: SHT_PROGBITS
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// APPLYDYNREL-NEXT: Flags [
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// APPLYDYNREL-NEXT: SHF_ALLOC
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// APPLYDYNREL-NEXT: SHF_WRITE
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// APPLYDYNREL-NEXT: ]
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// APPLYDYNREL-NEXT: Address: 0x2000
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// APPLYDYNREL-NEXT: Offset: 0x2000
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// APPLYDYNREL-NEXT: Size: 16
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// APPLYDYNREL-NEXT: Link: 0
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// APPLYDYNREL-NEXT: Info: 0
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// APPLYDYNREL-NEXT: AddressAlignment: 1
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// APPLYDYNREL-NEXT: EntrySize: 0
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// APPLYDYNREL-NEXT: SectionData (
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// APPLYDYNREL-NEXT: 0000: 00200000 00000000 00000000 00000000
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// APPLYDYNREL-NEXT: )
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// NOAPPLYDYNREL: Name: .data
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// NOAPPLYDYNREL-NEXT: Type: SHT_PROGBITS
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// NOAPPLYDYNREL-NEXT: Flags [
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// NOAPPLYDYNREL-NEXT: SHF_ALLOC
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// NOAPPLYDYNREL-NEXT: SHF_WRITE
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// NOAPPLYDYNREL-NEXT: ]
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// NOAPPLYDYNREL-NEXT: Address: 0x2000
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// NOAPPLYDYNREL-NEXT: Offset: 0x2000
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// NOAPPLYDYNREL-NEXT: Size: 16
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// NOAPPLYDYNREL-NEXT: Link: 0
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// NOAPPLYDYNREL-NEXT: Info: 0
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// NOAPPLYDYNREL-NEXT: AddressAlignment: 1
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// NOAPPLYDYNREL-NEXT: EntrySize: 0
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// NOAPPLYDYNREL-NEXT: SectionData (
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// NOAPPLYDYNREL-NEXT: 0000: 00000000 00000000 00000000 00000000
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// NOAPPLYDYNREL-NEXT: )
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// CHECK: Name: foo
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// CHECK-NEXT: Type: SHT_PROGBITS
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// CHECK-NEXT: Flags [
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// CHECK-NEXT: ]
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// CHECK-NEXT: Address: 0x0
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// CHECK-NEXT: Offset:
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// CHECK-NEXT: Size: 32
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// CHECK-NEXT: Link: 0
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// CHECK-NEXT: Info: 0
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// CHECK-NEXT: AddressAlignment: 1
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// CHECK-NEXT: EntrySize: 0
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// CHECK-NEXT: SectionData (
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// CHECK-NEXT: 0000: 00200000 00000000 00200000 00000000
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// CHECK-NEXT: 0010: 00200000 00000000 00200000 00000000
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// CHECK-NEXT: )
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// CHECK: Relocations [
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// CHECK-NEXT: Section ({{.}}) .rela.dyn {
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// CHECK-NEXT: 0x2000 R_X86_64_RELATIVE - 0x2000
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// CHECK-NEXT: 0x2008 R_X86_64_64 zed 0x0
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// CHECK-NEXT: }
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// CHECK-NEXT: ]
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.data
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.global zed
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zed:
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bar:
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.quad bar
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.quad zed
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.section foo
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.quad bar
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.quad zed
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.section foo
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.quad bar
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.quad zed
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