7b346357db
`findOrphanPos` finds the most similar output section (that has input sections). In the event of proximity ties, we select the first section. However, when an orphan section's rank is equal to or larger than the most similar sections's, it makes sense to prioritize the last similar section. This new behavior matches GNU ld better. ``` // orphan placement for .bss (SHF_ALLOC|SHF_WRITE, SHT_NOBITS) WA SHT_PROGBITS (old behavior) <= here A WA SHT_PROGBITS AX WA (.data) (new behavior) <= here ``` When the orphan section's rank is less, the current behavior prioritizing the first section still makes sense. ``` // orphan with a smaller rank, e.g. .rodata <= here WA AX WA ``` Close #92987 Pull Request: https://github.com/llvm/llvm-project/pull/94099
92 lines
4.3 KiB
ArmAsm
92 lines
4.3 KiB
ArmAsm
# REQUIRES: x86
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# RUN: split-file %s %t
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# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/main.s -o %t.o
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## Non-SHF_ALLOC sections are placed after all SHF_ALLOC sections. They will
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## thus not be contained in a PT_LOAD segment. data2 has a PT_LOAD segment,
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## even if it is preceded by a non-SHF_ALLOC section. Non-SHF_ALLOC orphan
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## sections have zero addresses.
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## NOTE: GNU ld assigns non-zero addresses to non-SHF_ALLOC non-orphan sections.
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# RUN: ld.lld -T %t/a.lds %t.o -o %ta
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# RUN: llvm-readelf -S -l %ta | FileCheck %s
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# CHECK: [Nr] Name Type Address Off Size ES Flg Lk
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# CHECK-NEXT: [ 0] NULL 0000000000000000 000000 000000 00 0
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# CHECK-NEXT: [ 1] .bss NOBITS 0000000000000000 001000 000001 00 WA 0
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# CHECK-NEXT: [ 2] data1 PROGBITS 0000000000000001 001001 000001 00 WA 0
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# CHECK-NEXT: [ 3] other1 PROGBITS 0000000000000000 001008 000001 00 0
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# CHECK-NEXT: [ 4] other2 PROGBITS 0000000000000000 001010 000001 00 0
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## Orphan placement places other3, .symtab, .shstrtab and .strtab after other2.
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# CHECK-NEXT: [ 5] other3 PROGBITS 0000000000000000 001020 000001 00 0
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# CHECK-NEXT: [ 6] .symtab SYMTAB 0000000000000000 001028 000030 18 8
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# CHECK-NEXT: [ 7] .shstrtab STRTAB 0000000000000000 001058 00004d 00 0
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# CHECK-NEXT: [ 8] .strtab STRTAB 0000000000000000 0010a5 000008 00 0
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# CHECK-NEXT: [ 9] data2 PROGBITS 0000000000000002 001002 000001 00 WA 0
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## max{sortRank(data1),sortRank(data2)} <= sortRank(data3). data3 is placed after the latter.
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# CHECK-NEXT: [10] data3 PROGBITS 0000000000000003 001003 000001 00 WA 0
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# CHECK-NEXT: [11] .text PROGBITS 0000000000000004 001004 000001 00 AX 0
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# CHECK: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
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# CHECK-NEXT: LOAD 0x001000 0x0000000000000000 0x0000000000000000 0x000004 0x000004 RW 0x1000
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# CHECK-NEXT: LOAD 0x001004 0x0000000000000004 0x0000000000000004 0x000001 0x000001 R E 0x1000
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# CHECK-NEXT: GNU_STACK 0x000000 0x0000000000000000 0x0000000000000000 0x000000 0x000000 RW 0
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# RUN: ld.lld -T %t/b.lds %t.o -o %tb
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# RUN: llvm-readelf -S -l %tb | FileCheck %s --check-prefix=CHECK1
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# CHECK1: [Nr] Name Type Address Off Size ES Flg Lk
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# CHECK1-NEXT: [ 0] NULL 0000000000000000 000000 000000 00 0
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# CHECK1-NEXT: [ 1] .text PROGBITS 00000000000000b0 0000b0 000001 00 AX 0
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# CHECK1-NEXT: [ 2] .bss NOBITS 00000000000000b1 0000b1 000001 00 WA 0
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# CHECK1-NEXT: [ 3] data1 PROGBITS 00000000000000b2 0000b2 000001 00 WA 0
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# CHECK1-NEXT: [ 4] other1 PROGBITS 0000000000000000 0000b8 000001 00 0
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# CHECK1-NEXT: [ 5] other2 PROGBITS 0000000000000000 0000c0 000001 00 0
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# CHECK1-NEXT: [ 6] other3 PROGBITS 0000000000000000 0000d0 000001 00 0
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# CHECK1-NEXT: [ 7] .symtab SYMTAB 0000000000000000 0000d8 000030 18 9
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# CHECK1-NEXT: [ 8] .shstrtab STRTAB 0000000000000000 000108 00004d 00 0
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# CHECK1-NEXT: [ 9] .strtab STRTAB 0000000000000000 000155 000008 00 0
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# CHECK1-NEXT: [10] data2 PROGBITS 00000000000000b3 0000b3 000001 00 WA 0
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# CHECK1-NEXT: [11] data3 PROGBITS 00000000000000b4 0000b4 000001 00 WA 0
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# CHECK1: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
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# CHECK1-NEXT: LOAD 0x000000 0x0000000000000000 0x0000000000000000 0x0000b5 0x0000b5 RWE 0x1000
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# CHECK1-NEXT: 0x60000000 0x0000b8 0x0000000000000000 0x0000000000000000 0x000009 0x000001 0x8
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#--- a.lds
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SECTIONS {
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.bss : { *(.bss) }
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data1 : { *(data1) }
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other1 : { *(other1) }
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other2 : { *(other2) }
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data2 : { *(data2) }
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.text : { *(.text) }
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/DISCARD/ : { *(.comment) }
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}
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#--- b.lds
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PHDRS {
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text PT_LOAD FILEHDR PHDRS;
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foo 0x60000000 FLAGS (0);
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}
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SECTIONS {
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. = SIZEOF_HEADERS;
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.text : { *(.text) } : text
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.bss : { *(.bss) } : text
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data1 : { *(data1) } : text
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other1 : { *(other1) } : foo
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other2 : { *(other2) } : foo
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data2 : { *(data1) } : text
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/DISCARD/ : { *(.comment) }
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}
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#--- main.s
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.globl _start
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_start: nop
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.section data1,"aw"; .byte 0
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.section data2,"aw"; .byte 0
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.section data3,"aw"; .byte 0
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.bss; .byte 0
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.section other1; .p2align 2; .byte 0
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.section other2; .p2align 3; .byte 0
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.section other3; .p2align 4; .byte 0
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