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Differential D129720

[JITLink][COFF] Don't dead strip COMDAT associative symbol.
ClosedPublic

Authored by sunho on Jul 13 2022, 7:27 PM.

Details

Reviewers
lhames
sgraenitz
Commits
rGb4878493dc3e: [JITLink][COFF] Don't dead strip COMDAT associative symbol.
Summary

This prevents the dead strip of associative comdat section when parent section is alive.

Diff Detail

Event Timeline

sunho created this revision.Jul 13 2022, 7:27 PM
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Herald added a subscriber: hiraditya. · View Herald Transcript
sunho requested review of this revision.Jul 13 2022, 7:27 PM
Herald added a project: Restricted Project. · View Herald TranscriptJul 13 2022, 7:27 PM
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sunho added reviewers: lhames, sgraenitz.Jul 13 2022, 7:29 PM
Herald added a subscriber: StephenFan. · View Herald TranscriptJul 13 2022, 7:29 PM
sunho edited the summary of this revision. (Show Details)Jul 13 2022, 7:29 PM
Harbormaster completed remote builds in B175284: Diff 444495.Jul 13 2022, 8:49 PM
sunho retitled this revision from [JITLink][COFF] Don't dead strip comdat associative symbol. to [JITLink][COFF] Don't dead strip COMDAT associative symbol..Jul 14 2022, 4:18 AM
sunho added a child revision: D129721: [JITLink][COFF] Handle out-of-order COMDAT second symbol..Jul 15 2022, 10:48 PM
sgraenitz accepted this revision.Jul 17 2022, 12:01 PM

LGTM. Thanks!

This revision is now accepted and ready to land.Jul 17 2022, 12:01 PM
Closed by commit rGb4878493dc3e: [JITLink][COFF] Don't dead strip COMDAT associative symbol. (authored by sunho). · Explain WhyJul 25 2022, 7:00 AM
This revision was automatically updated to reflect the committed changes.
sunho added a commit: rGb4878493dc3e: [JITLink][COFF] Don't dead strip COMDAT associative symbol..
sunho removed a child revision: D129721: [JITLink][COFF] Handle out-of-order COMDAT second symbol..Jul 25 2022, 7:02 AM

Revision Contents

PathSize
llvm/
lib/
ExecutionEngine/
JITLink/
6 lines
test/
ExecutionEngine/
JITLink/
X86/
63 lines
88 lines

Diff 444495

llvm/lib/ExecutionEngine/JITLink/COFFLinkGraphBuilder.cpp

Show First 20 Lines • Show All 415 Lines • ▼ Show 20 Lines const object::coff_aux_section_definition *Definition =
Symbol.getSectionDefinition(); Symbol.getSectionDefinition();
if (!Definition || !isComdatSection(Section)) { if (!Definition || !isComdatSection(Section)) {
// Handle typical static symbol // Handle typical static symbol
return &G->addDefinedSymbol( return &G->addDefinedSymbol(
*B, Symbol.getValue(), SymbolName, 0, Linkage::Strong, Scope::Local, *B, Symbol.getValue(), SymbolName, 0, Linkage::Strong, Scope::Local,
Symbol.getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION, false); Symbol.getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION, false);
} }
if (Definition->Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) { if (Definition->Selection == COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE) {
// FIXME: don't dead strip this when parent section is alive auto Target = Definition->getNumber(Symbol.isBigObj());
return &G->addDefinedSymbol( auto GSym = &G->addDefinedSymbol(
*B, Symbol.getValue(), SymbolName, 0, Linkage::Strong, Scope::Local, *B, Symbol.getValue(), SymbolName, 0, Linkage::Strong, Scope::Local,
Symbol.getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION, false); Symbol.getComplexType() == COFF::IMAGE_SYM_DTYPE_FUNCTION, false);
getGraphBlock(Target)->addEdge(Edge::KeepAlive, 0, *GSym, 0);
return GSym;
} }
if (PendingComdatExport) if (PendingComdatExport)
return make_error<JITLinkError>( return make_error<JITLinkError>(
"COMDAT export request already exists before symbol " + "COMDAT export request already exists before symbol " +
formatv("{0:d}", SymIndex)); formatv("{0:d}", SymIndex));
return createCOMDATExportRequest(SymIndex, Symbol, Definition); return createCOMDATExportRequest(SymIndex, Symbol, Definition);
} }
return make_error<JITLinkError>("Unsupported storage class " + return make_error<JITLinkError>("Unsupported storage class " +
▲ Show 20 Lines • Show All 83 Lines • ▼ Show 20 Lines LLVM_DEBUG({
dbgs() << " " << *Target << "\n"; dbgs() << " " << *Target << "\n";
}); });
PendingComdatExport = None; PendingComdatExport = None;
return Target; return Target;
} }
} // namespace jitlink } // namespace jitlink
} // namespace llvm } // namespace llvm
No newline at end of file No newline at end of file

llvm/test/ExecutionEngine/JITLink/X86/COFF_comdat_associative_dead_strip.test

  • This file was added.
# RUN: yaml2obj %s -o %t
# RUN: llvm-jitlink -noexec \
# RUN: -slab-allocate 100Kb -slab-address 0xfff00000 -slab-page-size 4096 \
# RUN: -show-graph -noexec %t 2>&1 | FileCheck %s
#
# Check a comdat child block connected by associative selection type is dead strip when
# parent block is dead.
#
# CHECK: section parent:
# CHECK-EMPTY:
# CHECK-NEXT: section child:
# CHECK-EMPTY:
--- !COFF
header:
Machine: IMAGE_FILE_MACHINE_AMD64
Characteristics: [ ]
sections:
- Name: .text
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
Alignment: 16
SectionData: '0000000000000000'
- Name: parent
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
Alignment: 16
SectionData: '0000000000000000'
- Name: child
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_READ ]
Alignment: 4
SectionData: '0000000000000000'
symbols:
- Name: .text
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 8
NumberOfRelocations: 0
CheckSum: 0
NumberOfLinenumbers: 0
Number: 1
- Name: child
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
Number: 2
CheckSum: 0
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: main
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_FUNCTION
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
...

llvm/test/ExecutionEngine/JITLink/X86/COFF_comdat_associative_no_dead_strip.test

  • This file was added.
# RUN: yaml2obj %s -o %t
# RUN: llvm-jitlink -noexec \
# RUN: -slab-allocate 100Kb -slab-address 0xfff00000 -slab-page-size 4096 \
# RUN: -show-graph -noexec %t 2>&1 | FileCheck %s
#
# Check a comdat child block connected by associative selection type is not dead strip when
# parent block is alive.
#
# CHECK: section child:
# CHECK-EMPTY:
# CHECK-NEXT: block 0xfff00000 size = 0x00000008, align = 4, alignment-offset = 0
# CHECK-NEXT: symbols:
# CHECK-NEXT: 0xfff00000 (block + 0x00000000): size: 0x00000008, linkage: strong, scope: local, live - child
# CHECK-NEXT: no edges
--- !COFF
header:
Machine: IMAGE_FILE_MACHINE_AMD64
Characteristics: [ ]
sections:
- Name: .text
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
Alignment: 16
SectionData: '0000000000000000'
Relocations:
- VirtualAddress: 0
SymbolTableIndex: 2
Type: IMAGE_REL_AMD64_REL32
- Name: parent
Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
Alignment: 16
SectionData: '0000000000000000'
- Name: child
Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_LNK_COMDAT, IMAGE_SCN_MEM_READ ]
Alignment: 4
SectionData: '0000000000000000'
symbols:
- Name: .text
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 8
NumberOfRelocations: 0
CheckSum: 0
NumberOfLinenumbers: 0
Number: 1
- Name: .text
Value: 0
SectionNumber: 2
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_STATIC
SectionDefinition:
Length: 8
NumberOfRelocations: 0
NumberOfLinenumbers: 0
CheckSum: 0
Number: 3
Selection: IMAGE_COMDAT_SELECT_ANY
- Name: func
Value: 0
SectionNumber: 2
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_FUNCTION
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
- Name: child
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
Number: 2
CheckSum: 0
Selection: IMAGE_COMDAT_SELECT_ASSOCIATIVE
- Name: main
Value: 0
SectionNumber: 1
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_FUNCTION
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
...