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[BOLT] Add constant island check in scanExternalRefs() #165577

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Merged
merged 2 commits into from
Oct 31, 2025
Merged

[BOLT] Add constant island check in scanExternalRefs() #165577

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0b280fe
add isInConstantIsland for scanExternalRefs
Jinjie-Huang Oct 29, 2025
a60a522
add document in test
Jinjie-Huang Oct 30, 2025
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16 changes: 13 additions & 3 deletions bolt/lib/Core/BinaryFunction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1699,9 +1699,19 @@ bool BinaryFunction::scanExternalRefs() {

const uint64_t FunctionOffset =
TargetAddress - TargetFunction->getAddress();
BranchTargetSymbol =
FunctionOffset ? TargetFunction->addEntryPointAtOffset(FunctionOffset)
: TargetFunction->getSymbol();
if (!TargetFunction->isInConstantIsland(TargetAddress)) {
BranchTargetSymbol =
FunctionOffset
? TargetFunction->addEntryPointAtOffset(FunctionOffset)
: TargetFunction->getSymbol();
} else {
TargetFunction->setIgnored();
BC.outs() << "BOLT-WARNING: Ignoring entry point at address 0x"
<< Twine::utohexstr(Address)
<< " in constant island of function " << *TargetFunction
<< '\n';
continue;
}
}

// Can't find more references. Not creating relocations since we are not
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9 changes: 7 additions & 2 deletions bolt/test/AArch64/constant-island-entry.s
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@@ -1,10 +1,15 @@
// This test checks that we ignore functions which add an entry point that
// is in a constant island.
## This test checks that we ignore functions which add an entry point that
## is in a constant island.

# RUN: llvm-mc -filetype=obj -triple aarch64-unknown-unknown %s -o %t.o
# RUN: %clang %cflags %t.o -pie -Wl,-q -o %t.exe

## Check when the caller is successfully disassembled.
# RUN: llvm-bolt %t.exe -o %t.bolt 2>&1 | FileCheck %s

## Skip caller to check the identical warning is triggered from ScanExternalRefs().
# RUN: llvm-bolt %t.exe -o %t.bolt -skip-funcs=caller 2>&1 | FileCheck %s

# CHECK: BOLT-WARNING: Ignoring entry point at address 0x{{[0-9a-f]+}} in constant island of function func

.globl func
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