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[BOLT][NFC] Simplify getOrCreate/analyze/populate/emitJumpTable (#132108)

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This commit is contained in:
Amir Ayupov 2025-04-10 21:17:04 -07:00 committed by GitHub
parent 04c38981a9
commit ba93fe97c2
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GPG Key ID: B5690EEEBB952194
3 changed files with 72 additions and 87 deletions
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75
bolt/lib/Core/BinaryContext.cpp
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@ -579,6 +579,21 @@ bool BinaryContext::analyzeJumpTable(const uint64_t Address,
TrimmedSize = EntriesAsAddress->size();
};
auto printEntryDiagnostics = [&](raw_ostream &OS,
const BinaryFunction *TargetBF) {
OS << "FAIL: function doesn't contain this address\n";
if (!TargetBF)
return;
OS << " ! function containing this address: " << *TargetBF << '\n';
if (!TargetBF->isFragment())
return;
OS << " ! is a fragment with parents: ";
ListSeparator LS;
for (BinaryFunction *Parent : TargetBF->ParentFragments)
OS << LS << *Parent;
OS << '\n';
};
ErrorOr<const BinarySection &> Section = getSectionForAddress(Address);
if (!Section)
return false;
@ -646,25 +661,8 @@ bool BinaryContext::analyzeJumpTable(const uint64_t Address,
// Function or one of its fragments.
const BinaryFunction *TargetBF = getBinaryFunctionContainingAddress(Value);
const bool DoesBelongToFunction =
BF.containsAddress(Value) ||
(TargetBF && areRelatedFragments(TargetBF, &BF));
if (!DoesBelongToFunction) {
LLVM_DEBUG({
if (!BF.containsAddress(Value)) {
dbgs() << "FAIL: function doesn't contain this address\n";
if (TargetBF) {
dbgs() << " ! function containing this address: "
<< TargetBF->getPrintName() << '\n';
if (TargetBF->isFragment()) {
dbgs() << " ! is a fragment";
for (BinaryFunction *Parent : TargetBF->ParentFragments)
dbgs() << ", parent: " << Parent->getPrintName();
dbgs() << '\n';
}
}
}
});
if (!TargetBF || !areRelatedFragments(TargetBF, &BF)) {
LLVM_DEBUG(printEntryDiagnostics(dbgs(), TargetBF));
break;
}
@ -703,10 +701,7 @@ void BinaryContext::populateJumpTables() {
++JTI) {
JumpTable *JT = JTI->second;
bool NonSimpleParent = false;
for (BinaryFunction *BF : JT->Parents)
NonSimpleParent |= !BF->isSimple();
if (NonSimpleParent)
if (!llvm::all_of(JT->Parents, std::mem_fn(&BinaryFunction::isSimple)))
continue;
uint64_t NextJTAddress = 0;
@ -840,33 +835,25 @@ BinaryContext::getOrCreateJumpTable(BinaryFunction &Function, uint64_t Address,
assert(JT->Type == Type && "jump table types have to match");
assert(Address == JT->getAddress() && "unexpected non-empty jump table");
if (llvm::is_contained(JT->Parents, &Function))
return JT->getFirstLabel();
// Prevent associating a jump table to a specific fragment twice.
if (!llvm::is_contained(JT->Parents, &Function)) {
assert(llvm::all_of(JT->Parents,
[&](const BinaryFunction *BF) {
return areRelatedFragments(&Function, BF);
}) &&
auto isSibling = std::bind(&BinaryContext::areRelatedFragments, this,
&Function, std::placeholders::_1);
assert(llvm::all_of(JT->Parents, isSibling) &&
"cannot re-use jump table of a different function");
// Duplicate the entry for the parent function for easy access
JT->Parents.push_back(&Function);
if (opts::Verbosity > 2) {
this->outs() << "BOLT-INFO: Multiple fragments access same jump table: "
<< JT->Parents[0]->getPrintName() << "; "
<< Function.getPrintName() << "\n";
this->outs() << "BOLT-INFO: multiple fragments access the same jump table"
<< ": " << *JT->Parents[0] << "; " << Function << '\n';
JT->print(this->outs());
}
if (JT->Parents.size() == 1)
JT->Parents.front()->setHasIndirectTargetToSplitFragment(true);
Function.setHasIndirectTargetToSplitFragment(true);
// Duplicate the entry for the parent function for easy access
JT->Parents.push_back(&Function);
Function.JumpTables.emplace(Address, JT);
for (BinaryFunction *Parent : JT->Parents)
Parent->setHasIndirectTargetToSplitFragment(true);
}
bool IsJumpTableParent = false;
(void)IsJumpTableParent;
for (BinaryFunction *Frag : JT->Parents)
if (Frag == &Function)
IsJumpTableParent = true;
assert(IsJumpTableParent &&
"cannot re-use jump table of a different function");
return JT->getFirstLabel();
}

26
bolt/lib/Core/BinaryEmitter.cpp
View File

@ -809,24 +809,23 @@ void BinaryEmitter::emitJumpTable(const JumpTable &JT, MCSection *HotSection,
Streamer.switchSection(JT.Count > 0 ? HotSection : ColdSection);
Streamer.emitValueToAlignment(Align(JT.EntrySize));
}
MCSymbol *LastLabel = nullptr;
MCSymbol *JTLabel = nullptr;
uint64_t Offset = 0;
for (MCSymbol *Entry : JT.Entries) {
auto LI = JT.Labels.find(Offset);
if (LI != JT.Labels.end()) {
if (LI == JT.Labels.end())
goto emitEntry;
JTLabel = LI->second;
LLVM_DEBUG({
dbgs() << "BOLT-DEBUG: emitting jump table " << LI->second->getName()
dbgs() << "BOLT-DEBUG: emitting jump table " << JTLabel->getName()
<< " (originally was at address 0x"
<< Twine::utohexstr(JT.getAddress() + Offset)
<< (Offset ? ") as part of larger jump table\n" : ")\n");
});
if (!LabelCounts.empty()) {
LLVM_DEBUG(dbgs() << "BOLT-DEBUG: jump table count: "
<< LabelCounts[LI->second] << '\n');
if (LabelCounts[LI->second] > 0)
Streamer.switchSection(HotSection);
else
Streamer.switchSection(ColdSection);
const uint64_t JTCount = LabelCounts[JTLabel];
LLVM_DEBUG(dbgs() << "BOLT-DEBUG: jump table count: " << JTCount << '\n');
Streamer.switchSection(JTCount ? HotSection : ColdSection);
Streamer.emitValueToAlignment(Align(JT.EntrySize));
}
// Emit all labels registered at the address of this jump table
@ -842,19 +841,18 @@ void BinaryEmitter::emitJumpTable(const JumpTable &JT, MCSection *HotSection,
// whenever this address is referenced in the binary, it is
// certain to point to the jump table identified at this
// address.
if (BinaryData *BD = BC.getBinaryDataByName(LI->second->getName())) {
if (BinaryData *BD = BC.getBinaryDataByName(JTLabel->getName())) {
for (MCSymbol *S : BD->getSymbols())
Streamer.emitLabel(S);
} else {
Streamer.emitLabel(LI->second);
}
LastLabel = LI->second;
Streamer.emitLabel(JTLabel);
}
emitEntry:
if (JT.Type == JumpTable::JTT_NORMAL) {
Streamer.emitSymbolValue(Entry, JT.OutputEntrySize);
} else { // JTT_PIC
const MCSymbolRefExpr *JTExpr =
MCSymbolRefExpr::create(LastLabel, Streamer.getContext());
MCSymbolRefExpr::create(JTLabel, Streamer.getContext());
const MCSymbolRefExpr *E =
MCSymbolRefExpr::create(Entry, Streamer.getContext());
const MCBinaryExpr *Value =

2
bolt/test/X86/split-func-jump-table-fragment-bidirection.s
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@ -10,7 +10,7 @@
# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q
# RUN: llvm-bolt -print-cfg -v=3 %t.exe -o %t.out 2>&1 | FileCheck %s
# CHECK: BOLT-INFO: Multiple fragments access same jump table: main; main.cold.1
# CHECK: BOLT-INFO: multiple fragments access the same jump table: main; main.cold.1
# CHECK: PIC Jump table JUMP_TABLE1 for function main, main.cold.1 at {{.*}} with a total count of 0:
.text