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Differential D11655

COFF: Sort output sections which start with .debug to the end of the file
ClosedPublic

Authored by majnemer on Jul 30 2015, 10:46 AM.

Details

Reviewers
ruiu
Commits
rG13ac40ea6ef9: COFF: Sort output sections which start with .debug to the end of the file
rLLD243680: COFF: Sort output sections which start with .debug to the end of the file
rL243680: COFF: Sort output sections which start with .debug to the end of the file
Summary

We want to convince the NT loader not to map these sections into memory.
A good first step is to move them to the end of the executable.

Diff Detail

Repository
rL LLVM

Event Timeline

majnemer updated this revision to Diff 31049.Jul 30 2015, 10:46 AM
majnemer retitled this revision from to COFF: Sort output sections which start with .debug to the end of the file.
majnemer updated this object.
majnemer added a reviewer: ruiu.
majnemer added a subscriber: llvm-commits.
ruiu added inline comments.Jul 30 2015, 12:58 PM
COFF/Writer.cpp
405 ↗(On Diff #31049)

I'd check for S->getPermissions() & DISCARDABLE.

majnemer updated this revision to Diff 31067.Jul 30 2015, 1:12 PM
  • Address review comments
ruiu accepted this revision.Jul 30 2015, 1:16 PM
ruiu edited edge metadata.

LGTM with a nit.

COFF/Writer.cpp
401 ↗(On Diff #31067)

Please add a comment saying that the code is to move DISCARDABLE (or non-memory-mapped) sections to the end of file because the loader cannnot handle holes.

This revision is now accepted and ready to land.Jul 30 2015, 1:16 PM
Closed by commit rL243680: COFF: Sort output sections which start with .debug to the end of the file (authored by majnemer). · Explain WhyJul 30 2015, 1:27 PM
This revision was automatically updated to reflect the committed changes.
mstorsjo mentioned this in D120805: [LLD] [COFF] Order .debug_* sections at the end, to avoid leaving gaps if stripped.Mar 2 2022, 3:03 AM

Revision Contents

PathSize
lld/
trunk/
COFF/
6 lines
test/
COFF/
2 lines
296 lines

Diff 31069

lld/trunk/COFF/Writer.cpp

Show First 20 Lines • Show All 392 Lines • ▼ Show 20 Linesvoid Writer::assignAddresses() {
SizeOfHeaders = DOSStubSize + sizeof(PEMagic) + sizeof(coff_file_header) + SizeOfHeaders = DOSStubSize + sizeof(PEMagic) + sizeof(coff_file_header) +
sizeof(data_directory) * NumberfOfDataDirectory + sizeof(data_directory) * NumberfOfDataDirectory +
sizeof(coff_section) * OutputSections.size(); sizeof(coff_section) * OutputSections.size();
SizeOfHeaders += SizeOfHeaders +=
Config->is64() ? sizeof(pe32plus_header) : sizeof(pe32_header); Config->is64() ? sizeof(pe32plus_header) : sizeof(pe32_header);
SizeOfHeaders = RoundUpToAlignment(SizeOfHeaders, PageSize); SizeOfHeaders = RoundUpToAlignment(SizeOfHeaders, PageSize);
uint64_t RVA = 0x1000; // The first page is kept unmapped. uint64_t RVA = 0x1000; // The first page is kept unmapped.
uint64_t FileOff = SizeOfHeaders; uint64_t FileOff = SizeOfHeaders;
// Move DISCARDABLE (or non-memory-mapped) sections to the end of file because
// the loader cannot handle holes.
std::stable_partition(
OutputSections.begin(), OutputSections.end(), [](OutputSection *S) {
return (S->getPermissions() & IMAGE_SCN_MEM_DISCARDABLE) == 0;
});
for (OutputSection *Sec : OutputSections) { for (OutputSection *Sec : OutputSections) {
if (Sec->getName() == ".reloc") if (Sec->getName() == ".reloc")
addBaserels(Sec); addBaserels(Sec);
Sec->setRVA(RVA); Sec->setRVA(RVA);
Sec->setFileOffset(FileOff); Sec->setFileOffset(FileOff);
RVA += RoundUpToAlignment(Sec->getVirtualSize(), PageSize); RVA += RoundUpToAlignment(Sec->getVirtualSize(), PageSize);
FileOff += RoundUpToAlignment(Sec->getRawSize(), FileAlignment); FileOff += RoundUpToAlignment(Sec->getRawSize(), FileAlignment);
} }
▲ Show 20 Lines • Show All 291 Lines • Show Last 20 Lines

lld/trunk/test/COFF/seh.test

# RUN: yaml2obj < %s > %t.obj # RUN: yaml2obj < %s > %t.obj
# RUN: lld -flavor link2 /out:%t.exe /subsystem:console /entry:main %t.obj # RUN: lld -flavor link2 /out:%t.exe /subsystem:console /entry:main %t.obj
# RUN: llvm-objdump -s %t.exe | FileCheck %s # RUN: llvm-objdump -s %t.exe | FileCheck %s
# CHECK: Contents of section .rdata: # CHECK: Contents of section .rdata:
# CHECK: 2000 00100000 02100000 # CHECK: 1000 00200000 02200000
--- ---
header: header:
Machine: IMAGE_FILE_MACHINE_I386 Machine: IMAGE_FILE_MACHINE_I386
Characteristics: [ ] Characteristics: [ ]
sections: sections:
- Name: .text - Name: .text
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ] Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
▲ Show 20 Lines • Show All 56 Lines • Show Last 20 Lines

lld/trunk/test/COFF/sort-debug.test

# RUN: yaml2obj < %s > %t.obj
# RUN: lld -flavor link2 /debug /out:%t.exe /entry:main %t.obj
# RUN: llvm-readobj -sections %t.exe | FileCheck %s
# CHECK: Name: .text
# CHECK: Name: .debug_abbrev
# CHECK: Name: .debug_info
# CHECK: Name: .debug_line
# CHECK: Name: .debug_pubnames
# CHECK: Name: .debug_pubtypes
# CHECK: Name: .reloc
---
header:
Machine: IMAGE_FILE_MACHINE_I386
Characteristics: [ ]
sections:
- Name: .text
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
Alignment: 16
SectionData: 508D0500000000C70424000000005AC3
Relocations:
- VirtualAddress: 3
SymbolName: '?x@@3HA'
Type: IMAGE_REL_I386_DIR32
- Name: .data
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
Alignment: 4
SectionData: ''
- Name: .bss
Characteristics: [ IMAGE_SCN_CNT_UNINITIALIZED_DATA, IMAGE_SCN_MEM_READ, IMAGE_SCN_MEM_WRITE ]
Alignment: 4
SectionData: ''
- Name: '.debug$S'
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 04000000F1000000300000002A00471100000000000000000000000010000000000000000000000000000000000000000000006D61696E0002004F11F200000024000000000000000000010010000000000000000100000018000000000000000100000000000000F4000000080000000100000000000000F30000003C000000005C7573725C6C6F63616C5C676F6F676C655C686F6D655C6D616A6E656D65725C6C6C766D5C7372635C746F6F6C735C6C6C645C3C737464696E3E00
Relocations:
- VirtualAddress: 44
SymbolName: _main
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 48
SymbolName: _main
Type: IMAGE_REL_I386_SECTION
- VirtualAddress: 68
SymbolName: _main
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 72
SymbolName: _main
Type: IMAGE_REL_I386_SECTION
- Name: .debug_str
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: ''
- Name: .debug_loc
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: ''
- Name: .debug_abbrev
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 011101250E1305030E10171B0E110112060000023400030E49133F193A0B3B0B02186E0E0000032400030E3E0B0B0B0000042E0011011206E77F194018030E3A0B3B0B49133F19000000
- Name: .debug_info
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 54000000040000000000040100000000040037000000000000003F000000000000001000000002720000003B0000000101050300000000780000000374000000050404000000001000000001548000000001013B00000000
Relocations:
- VirtualAddress: 6
SymbolName: .debug_abbrev
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 12
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 18
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 22
SymbolName: .debug_line
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 26
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 30
SymbolName: .text
Type: IMAGE_REL_I386_DIR32
- VirtualAddress: 39
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 51
SymbolName: '?x@@3HA'
Type: IMAGE_REL_I386_DIR32
- VirtualAddress: 55
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 60
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- VirtualAddress: 67
SymbolName: .text
Type: IMAGE_REL_I386_DIR32
- VirtualAddress: 77
SymbolName: .debug_str
Type: IMAGE_REL_I386_SECREL
- Name: .debug_ranges
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: ''
- Name: .debug_pubnames
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 1D00000002000000000058000000420000006D61696E0026000000780000000000
Relocations:
- VirtualAddress: 6
SymbolName: .debug_info
Type: IMAGE_REL_I386_SECREL
- Name: .debug_pubtypes
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 16000000020000000000580000003B000000696E740000000000
Relocations:
- VirtualAddress: 6
SymbolName: .debug_info
Type: IMAGE_REL_I386_SECREL
- Name: .debug_line
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_DISCARDABLE, IMAGE_SCN_MEM_READ ]
Alignment: 1
SectionData: 3300000002001E0000000101FB0E0D000101010100000001000001003C737464696E3E000000000000050200000000010AD60202000101
Relocations:
- VirtualAddress: 43
SymbolName: .text
Type: IMAGE_REL_I386_DIR32
symbols:
- Name: .text
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 16
NumberOfRelocations: 1
NumberOfLinenumbers: 0
CheckSum: 0
Number: 1
- Name: .data
Value: 0
SectionNumber: 2
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 0
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 2
- Name: .bss
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: 3
- Name: '.debug$S'
Value: 0
SectionNumber: 4
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 188
NumberOfRelocations: 4
NumberOfLinenumbers: 0
CheckSum: 0
Number: 4
- Name: .debug_str
Value: 0
SectionNumber: 5
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 133
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 5
- Name: .debug_loc
Value: 0
SectionNumber: 6
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 0
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 6
- Name: .debug_abbrev
Value: 0
SectionNumber: 7
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 74
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 7
- Name: .debug_info
Value: 0
SectionNumber: 8
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 88
NumberOfRelocations: 12
NumberOfLinenumbers: 0
CheckSum: 0
Number: 8
- Name: .debug_ranges
Value: 0
SectionNumber: 9
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 0
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 9
- Name: .debug_pubnames
Value: 0
SectionNumber: 10
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 33
NumberOfRelocations: 1
NumberOfLinenumbers: 0
CheckSum: 0
Number: 10
- Name: .debug_pubtypes
Value: 0
SectionNumber: 11
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 26
NumberOfRelocations: 1
NumberOfLinenumbers: 0
CheckSum: 0
Number: 11
- Name: .debug_line
Value: 0
SectionNumber: 12
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 55
NumberOfRelocations: 1
NumberOfLinenumbers: 0
CheckSum: 0
Number: 12
- Name: '@feat.00'
Value: 1
SectionNumber: -1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
- Name: _main
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_FUNCTION
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
- Name: '?x@@3HA'
Value: 0
SectionNumber: 3
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
...