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[BOLT][RelVTable] Skip special handling on non virtual function pointer relocations (#137406)

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Besides virtual function pointers vtable could contain other kinds of
entries like those for RTTI data that also require relocations. We need
to skip special handling on relocations for non virtual function pointers
in relative vtable.

Co-authored-by: Maksim Panchenko <maks@meta.com>
This commit is contained in:
YongKang Zhu 2025-04-29 08:13:44 -07:00 committed by GitHub
parent 900505900e
commit 316a6ff3d0
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GPG Key ID: B5690EEEBB952194
2 changed files with 47 additions and 13 deletions
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25
bolt/lib/Rewrite/RewriteInstance.cpp
View File

@ -2697,20 +2697,19 @@ void RewriteInstance::handleRelocation(const SectionRef &RelocatedSection,
BD->nameStartsWith("_ZTCN"))) { // construction vtable BD->nameStartsWith("_ZTCN"))) { // construction vtable
BinaryFunction *BF = BC->getBinaryFunctionContainingAddress( BinaryFunction *BF = BC->getBinaryFunctionContainingAddress(
SymbolAddress, /*CheckPastEnd*/ false, /*UseMaxSize*/ true); SymbolAddress, /*CheckPastEnd*/ false, /*UseMaxSize*/ true);
if (!BF || BF->getAddress() != SymbolAddress) { if (BF) {
BC->errs() if (BF->getAddress() != SymbolAddress) {
<< "BOLT-ERROR: the virtual function table entry at offset 0x" BC->errs()
<< Twine::utohexstr(Rel.getOffset()); << "BOLT-ERROR: the virtual function table entry at offset 0x"
if (BF) << Twine::utohexstr(Rel.getOffset())
BC->errs() << " points to the middle of a function @ 0x" << " points to the middle of a function @ 0x"
<< Twine::utohexstr(BF->getAddress()) << "\n"; << Twine::utohexstr(BF->getAddress()) << "\n";
else exit(1);
BC->errs() << " does not point to any function\n"; }
exit(1); BC->addRelocation(Rel.getOffset(), BF->getSymbol(), RType, Addend,
ExtractedValue);
return;
} }
BC->addRelocation(Rel.getOffset(), BF->getSymbol(), RType, Addend,
ExtractedValue);
return;
} }
} }

35
bolt/test/AArch64/skip-non-vfuncptr-reloc-in-relative-vtable.s Normal file
View File

@ -0,0 +1,35 @@
// Test the fix that BOLT should skip special handling of any non-virtual
// function pointer relocations in relative vtable.
// RUN: llvm-mc -filetype=obj -triple aarch64-unknown-gnu %s -o %t.o
// RUN: %clang %cxxflags -fuse-ld=lld %t.o -o %t.so -Wl,-q
// RUN: llvm-bolt %t.so -o %t.bolted.so
.text
.p2align 2
.type foo,@function
foo:
.cfi_startproc
adrp x8, _ZTV3gooE
add x8, x8, :lo12:_ZTV3gooE
ldr x0, [x8]
ret
.Lfunc_end0:
.size foo, .Lfunc_end0-foo
.cfi_endproc
.type _fake_rtti_data,@object
.section .rodata.cst16._fake_rtti_data,"aMG",@progbits,16,_fake_rtti_data,comdat
.p2align 3, 0x0
_fake_rtti_data:
.ascii "_FAKE_RTTI_DATA_"
.size _fake_rtti_data, 16
.type _ZTV3gooE,@object
.section .rodata,"a",@progbits
.p2align 2, 0x0
_ZTV3gooE:
.word 0
.word _fake_rtti_data-_ZTV3gooE-8
.word foo@PLT-_ZTV3gooE-8
.size _ZTV3gooE, 12