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[BOLT] Skip creation of new segments #146023

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Merged
merged 1 commit into from
Jun 27, 2025
Merged

[BOLT] Skip creation of new segments #146023

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5 changes: 5 additions & 0 deletions bolt/lib/Rewrite/RewriteInstance.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4190,6 +4190,11 @@ void RewriteInstance::patchELFPHDRTable() {
NewWritableSegmentSize = NextAvailableAddress - NewWritableSegmentAddress;
}

if (!NewTextSegmentSize && !NewWritableSegmentSize) {
BC->outs() << "BOLT-INFO: not adding new segments\n";
return;
}

const uint64_t SavedPos = OS.tell();
OS.seek(PHDRTableOffset);

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14 changes: 14 additions & 0 deletions bolt/test/program-header.test
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Original file line number Diff line number Diff line change
@@ -0,0 +1,14 @@
# Check that llvm-bolt does not add new segments when writing code in-place.

REQUIRES: system-linux

RUN: %clang %cflags %p/Inputs/hello.c -o %t -no-pie -Wl,-q
RUN: llvm-bolt %t -o %t.bolt --use-old-text --align-functions=1 \
RUN: --no-huge-pages --align-text=1 --use-gnu-stack \
RUN: | FileCheck %s --check-prefix=CHECK-BOLT
RUN: llvm-readelf -WS %t.bolt | FileCheck %s

CHECK-BOLT: rewriting .eh_frame_hdr in-place
CHECK-BOLT: not adding new segments

CHECK-NOT: .bolt.org.eh_frame_hdr
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