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[BOLT] Skip FDE emission for patch functions #136224

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Merged
maksfb merged 2 commits into from
Apr 18, 2025
Merged

[BOLT] Skip FDE emission for patch functions #136224

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2316b4f
[BOLT] Skip FDE emission for patch functions
maksfb Apr 17, 2025
48fb627
fixup! [BOLT] Skip FDE emission for patch functions
maksfb Apr 18, 2025
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4 changes: 2 additions & 2 deletions bolt/lib/Core/BinaryEmitter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -374,7 +374,7 @@ bool BinaryEmitter::emitFunction(BinaryFunction &Function,
}

// Emit CFI start
if (Function.hasCFI()) {
if (Function.hasCFI() && !Function.isPatch()) {
Streamer.emitCFIStartProc(/*IsSimple=*/false);
if (Function.getPersonalityFunction() != nullptr)
Streamer.emitCFIPersonality(Function.getPersonalityFunction(),
Expand Down Expand Up @@ -421,7 +421,7 @@ bool BinaryEmitter::emitFunction(BinaryFunction &Function,
Streamer.emitBytes(BC.MIB->getTrapFillValue());

// Emit CFI end
if (Function.hasCFI())
if (Function.hasCFI() && !Function.isPatch())
Streamer.emitCFIEndProc();

MCSymbol *EndSymbol = Function.getFunctionEndLabel(FF.getFragmentNum());
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7 changes: 7 additions & 0 deletions bolt/test/AArch64/lite-mode.s
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Expand Up @@ -11,6 +11,13 @@
# RUN: llvm-objdump -d --disassemble-symbols=cold_function %t.bolt \
# RUN: | FileCheck %s


## Verify that the number of FDEs matches the number of functions in the output
## binary. There are three original functions and two optimized.
# RUN: llvm-readelf -u %t.bolt | grep -wc FDE \
# RUN: | FileCheck --check-prefix=CHECK-FDE %s
# CHECK-FDE: 5

## In lite mode, optimized code will be separated from the original .text by
## over 128MB, making it impossible for call/bl instructions in cold functions
## to reach optimized functions directly.
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