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release/19.x: [BOLT] Support map other function entry address (#101466) #102282

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Merged
merged 1 commit into from
Aug 10, 2024
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release/19.x: [BOLT] Support map other function entry address (#101466) #102282

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8 changes: 8 additions & 0 deletions bolt/lib/Rewrite/RewriteInstance.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5498,6 +5498,14 @@ uint64_t RewriteInstance::getNewFunctionOrDataAddress(uint64_t OldAddress) {
if (const BinaryFunction *BF =
BC->getBinaryFunctionContainingAddress(OldAddress)) {
if (BF->isEmitted()) {
// If OldAddress is the another entry point of
// the function, then BOLT could get the new address.
if (BF->isMultiEntry()) {
for (const BinaryBasicBlock &BB : *BF)
if (BB.isEntryPoint() &&
(BF->getAddress() + BB.getOffset()) == OldAddress)
return BF->getOutputAddress() + BB.getOffset();
}
BC->errs() << "BOLT-ERROR: unable to get new address corresponding to "
"input address 0x"
<< Twine::utohexstr(OldAddress) << " in function " << *BF
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32 changes: 32 additions & 0 deletions bolt/test/X86/dynamic-relocs-on-entry.s
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@@ -0,0 +1,32 @@
// This test examines whether BOLT can correctly process when
// dynamic relocation points to other entry points of the
// function.

# RUN: %clang %cflags -fPIC -pie %s -o %t.exe -nostdlib -Wl,-q
# RUN: llvm-bolt %t.exe -o %t.bolt > %t.out.txt
# RUN: readelf -r %t.bolt >> %t.out.txt
# RUN: llvm-objdump --disassemble-symbols=chain %t.bolt >> %t.out.txt
# RUN: FileCheck %s --input-file=%t.out.txt

## Check if the new address in `chain` is correctly updated by BOLT
# CHECK: Relocation section '.rela.dyn' at offset 0x{{.*}} contains 1 entry:
# CHECK: {{.*}} R_X86_64_RELATIVE [[#%x,ADDR:]]
# CHECK: [[#ADDR]]: c3 retq
.text
.type chain, @function
chain:
movq $1, %rax
Label:
ret
.size chain, .-chain

.type _start, @function
.global _start
_start:
jmpq *.Lfoo(%rip)
ret
.size _start, .-_start

.data
.Lfoo:
.quad Label
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