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lld: relocate PHDR if sectionStartMap is not empty #140126

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pskrgag wants to merge 1 commit into from
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lld: relocate PHDR if sectionStartMap is not empty #140126

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2 changes: 1 addition & 1 deletion lld/ELF/Writer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -331,7 +331,7 @@ template <class ELFT> void Writer<ELFT>::run() {
for (OutputSection *sec : ctx.outputSections)
sec->maybeCompress<ELFT>(ctx);

if (ctx.script->hasSectionsCommand)
if (ctx.script->hasSectionsCommand || !ctx.arg.sectionStartMap.empty())
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@MaskRay MaskRay May 16, 2025

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I don't think we should call allocateHeaders for the additional condition.

The user might specify --section-start to increase the address of a section. It should not change ELF header/program headers behavior.

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@pskrgag pskrgag May 16, 2025

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Ok, thanks for review! Closing pr in favor of #140187

ctx.script->allocateHeaders(ctx.mainPart->phdrs);

// Remove empty PT_LOAD to avoid causing the dynamic linker to try to mmap a
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24 changes: 24 additions & 0 deletions lld/test/ELF/sectionstart.s
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Expand Up @@ -11,6 +11,30 @@
# CHECK-NEXT: 2 .data 00000004 0000000000110000 DATA
# CHECK-NEXT: 3 .bss 00000004 0000000000200000 BSS

## Check that PHDRS are allocated below .text if .text is below default
## base for non-pie case

# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
# RUN: ld.lld %t.o -Ttext=0x3000 -o %t
# RUN: llvm-readelf -l %t | FileCheck --check-prefix=CHECK-TEXT %s

# CHECK-TEXT: Program Headers:
# CHECK-TEXT-NEXT: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
# CHECK-TEXT-NEXT: PHDR 0x000040 0x0000000000002040 0x0000000000002040 0x000118 0x000118 R 0x8
# CHECK-TEXT-NEXT: LOAD 0x000000 0x0000000000002000 0x0000000000002000 0x000158 0x000158 R 0x1000
# CHECK-TEXT-NEXT: LOAD 0x001000 0x0000000000003000 0x0000000000003000 0x000001 0x000001 R E 0x1000

## Check that PHDRS are deleted if they don't fit

# RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %s -o %t.o
# RUN: ld.lld %t.o -Ttext=0x0 -o %t
# RUN: llvm-readelf -l %t | FileCheck --check-prefix=CHECK-TEXT-ZERO %s

# CHECK-TEXT-ZERO: Program Headers:
# CHECK-TEXT-ZERO-NEXT: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align
# CHECK-TEXT-ZERO-NEXT: LOAD 0x001000 0x0000000000000000 0x0000000000000000 0x000001 0x000001 R E 0x1000
# CHECK-TEXT-ZERO-NEXT: LOAD 0x001001 0x0000000000001001 0x0000000000001001 0x000004 0x000008 RW 0x1000

## The same, but dropped "0x" prefix.
# RUN: ld.lld %t.o --section-start .text=100000 \
# RUN: --section-start .data=110000 --section-start .bss=0x200000 -o %t1
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2 changes: 0 additions & 2 deletions lld/test/ELF/ttext-tdata-tbss.s
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Expand Up @@ -24,8 +24,6 @@
# USER1-NEXT: .rodata PROGBITS 0000000000009008 002008 000008
# USER1-NEXT: .aw PROGBITS 000000000000a010 002010 000008
# USER1: Type
# USER1-NEXT: PHDR 0x000040 0x0000000000200040
# USER1-NEXT: LOAD 0x000000 0x0000000000200000
# USER1-NEXT: LOAD 0x001000 0x0000000000000000

## Specify --image-base to make program headers look normal.
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