[llvm-objcopy] [COFF] Ignore associative sections in executables (#151143)

COFF associative sections is a feature where relocatable object files
can have section snippets marked as related to another section snippet,
so they are kept or discarded in relation to that other section snippet.

When llvm-objcopy removes sections, it also removes sections that are
marked as associative to the removed section (as the associative
sections otherwise would end up orphaned).

In a linked executable module (EXE or DLL), section associativity is
meaningless - thus, we should ignore those fields from the input.

After linking, GNU ld keeps the SectionDefinition auxillary part of
symbols intact as it was in the source object file, which means that it
references section numbers in the source object files.

This fixes https://github.com/llvm/llvm-project/issues/53433.
This commit is contained in:
Martin Storsjö 2025-07-30 15:39:04 +02:00 committed by GitHub
parent deced287ad
commit fcbbcffd2e
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2 changed files with 135 additions and 1 deletions

View File

@ -135,7 +135,7 @@ Error COFFReader::readSymbols(Object &Obj, bool IsBigObj) const {
// it is, find the target section unique id.
const coff_aux_section_definition *SD = SymRef.getSectionDefinition();
const coff_aux_weak_external *WE = SymRef.getWeakExternal();
if (SD && SD->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
if (SD && SD->Selection == IMAGE_COMDAT_SELECT_ASSOCIATIVE && !Obj.IsPE) {
int32_t Index = SD->getNumber(IsBigObj);
if (Index <= 0 || static_cast<uint32_t>(Index - 1) >= Sections.size())
return createStringError(object_error::parse_failed,

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@ -0,0 +1,134 @@
## Test that bogus associative section symbols in executables are ignored.
##
## The executable contains two (bogus) associative section symbols, both for
## (parts of) the .rdata section; one pointing at the .debug_info section
## (which will be stripped out) and one pointing at a nonexistent section.
##
## Check that stripping does succeed, and that it doesn't end up removing
## the .rdata section.
# RUN: yaml2obj %s -o %t.in.exe
# RUN: llvm-strip --strip-debug %t.in.exe -o %t.out.exe
# RUN: llvm-readobj --sections %t.out.exe | FileCheck %s
# CHECK: Name: .rdata
--- !COFF
OptionalHeader:
AddressOfEntryPoint: 4096
ImageBase: 5368709120
SectionAlignment: 4096
FileAlignment: 512
MajorOperatingSystemVersion: 4
MinorOperatingSystemVersion: 0
MajorImageVersion: 0
MinorImageVersion: 0
MajorSubsystemVersion: 5
MinorSubsystemVersion: 2
Subsystem: IMAGE_SUBSYSTEM_WINDOWS_CUI
DLLCharacteristics: [ ]
SizeOfStackReserve: 2097152
SizeOfStackCommit: 4096
SizeOfHeapReserve: 1048576
SizeOfHeapCommit: 4096
header:
Machine: IMAGE_FILE_MACHINE_AMD64
Characteristics: [ ]
sections:
- Name: .text
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
VirtualAddress: 4096
VirtualSize: 48
SectionData: E806000000E802000000C3C3C30F1F00FFFFFFFFFFFFFFFF0000000000000000FFFFFFFFFFFFFFFF0000000000000000
SizeOfRawData: 512
- Name: .rdata
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
VirtualAddress: 8192
VirtualSize: 4
SectionData: '00000000'
SizeOfRawData: 512
- Name: .debug_info
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
VirtualAddress: 16384
VirtualSize: 4
SectionData: '00000000'
SizeOfRawData: 512
symbols:
- Name: .text
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 11
NumberOfRelocations: 2
NumberOfLinenumbers: 0
CheckSum: 1703692295
Number: 1
- Name: '.text$func1'
Value: 11
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 1
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 40735498
Number: 3
Selection: IMAGE_COMDAT_SELECT_ANY
- Name: .rdata
Value: 0
SectionNumber: 2
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 1
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 3
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: '.text$func2'
Value: 12
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 1
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 40735498
Number: 4
Selection: IMAGE_COMDAT_SELECT_ANY
- Name: .rdata
Value: 1
SectionNumber: 2
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 1
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 4
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: .debug_info
Value: 0
SectionNumber: 3
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 4
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 0
...