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[BOLT] Refactor markAmbiguousRelocations()

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Summary:
Refactor markAmbiguousRelocations() code and move it to BinaryContext.

Also remove a redundant check.

(cherry picked from FBD18623815)
This commit is contained in:
Maksim Panchenko
2019-11-18 14:08:17 -08:00
parent 658f270417
commit a09659fd54
3 changed files with 39 additions and 60 deletions
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31
bolt/src/BinaryContext.cpp
View File

@@ -1730,6 +1730,37 @@ const Relocation *BinaryContext::getRelocationAt(uint64_t Address) {
return Section->getRelocationAt(Address - Section->getAddress());
}
void BinaryContext::markAmbiguousRelocations(BinaryData &BD,
const uint64_t Address) {
auto setImmovable = [&](BinaryData &BD) {
auto *Root = BD.getAtomicRoot();
DEBUG(if (Root->isMoveable()) {
dbgs() << "BOLT-DEBUG: setting " << *Root << " as immovable "
<< "due to ambiguous relocation referencing 0x"
<< Twine::utohexstr(Address) << '\n';
});
Root->setIsMoveable(false);
};
if (Address == BD.getAddress()) {
setImmovable(BD);
// Set previous symbol as immovable
auto *Prev = getBinaryDataContainingAddress(Address-1);
if (Prev && Prev->getEndAddress() == BD.getAddress())
setImmovable(*Prev);
}
if (Address == BD.getEndAddress()) {
setImmovable(BD);
// Set next symbol as immovable
auto *Next = getBinaryDataContainingAddress(BD.getEndAddress());
if (Next && Next->getAddress() == BD.getEndAddress())
setImmovable(*Next);
}
}
void BinaryContext::exitWithBugReport(StringRef Message,
const BinaryFunction &Function) const {
errs() << "=======================================\n";

5
bolt/src/BinaryContext.h
View File

@@ -912,6 +912,11 @@ public:
/// is no relocation at such address.
const Relocation *getRelocationAt(uint64_t Address);
/// This function makes sure that symbols referenced by ambiguous relocations
/// are marked as immovable. For now, if a section relocation points at the
/// boundary between two symbols then those symbols are marked as immovable.
void markAmbiguousRelocations(BinaryData &BD, const uint64_t Address);
/// This function is thread safe.
const BinaryFunction *getFunctionForSymbol(const MCSymbol *Symbol) const {
std::shared_lock<std::shared_timed_mutex> Lock(SymbolToFunctionMapMutex);

63
bolt/src/RewriteInstance.cpp
View File

@@ -2346,7 +2346,6 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
}
}
uint64_t RefFunctionOffset = 0;
MCSymbol *ReferencedSymbol = nullptr;
if (ForceRelocation) {
auto Name = Relocation::isGOT(RType) ? "Zero" : SymbolName;
@@ -2358,6 +2357,7 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
<< SymbolName << " with addend " << Addend << '\n');
} else if (ReferencedBF) {
ReferencedSymbol = ReferencedBF->getSymbol();
uint64_t RefFunctionOffset = 0;
// Adjust the point of reference to a code location inside a function.
if (ReferencedBF->containsAddress(Address, /*UseMaxSize = */true)) {
@@ -2400,60 +2400,6 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
Addend = 0;
}
// This function makes sure that symbols referenced by ambiguous
// relocations are marked as unmoveable. For now, if a section
// relocation points at the boundary between two symbols then
// those symbols are marked as unmoveable.
auto markAmbiguousRelocations = [&](BinaryData *BD) {
if (Address == BD->getAddress()) {
BD = BD->getAtomicRoot();
DEBUG(if (BD->isMoveable()) {
dbgs() << "BOLT-DEBUG: setting " << *BD << " as unmoveable "
<< "due to ambiguous relocation (0x"
<< Twine::utohexstr(Address) << ") @ 0x"
<< Twine::utohexstr(Rel.getOffset()) << "\n";
});
BD->setIsMoveable(false);
// set previous symbol as unmoveable
auto *Prev = BC->getBinaryDataContainingAddress(Address-1);
if (Prev && Prev->getEndAddress() == BD->getAddress()) {
Prev = Prev->getAtomicRoot();
DEBUG(if (Prev->isMoveable()) {
dbgs() << "BOLT-DEBUG: setting " << *Prev << " as unmoveable "
<< "due to ambiguous relocation (0x"
<< Twine::utohexstr(Address) << ") @ 0x"
<< Twine::utohexstr(Rel.getOffset()) << "\n";
});
Prev->setIsMoveable(false);
}
}
if (Address == BD->getEndAddress()) {
BD = BD->getAtomicRoot();
DEBUG(if (BD->isMoveable()) {
dbgs() << "BOLT-DEBUG: setting " << *BD << " as unmoveable "
<< "due to ambiguous relocation (0x"
<< Twine::utohexstr(Address) << ") @ 0x"
<< Twine::utohexstr(Rel.getOffset()) << "\n";
});
BD->setIsMoveable(false);
// set next symbol as unmoveable
auto *Next = BC->getBinaryDataContainingAddress(BD->getEndAddress());
if (Next && Next->getAddress() == BD->getEndAddress()) {
Next = Next->getAtomicRoot();
DEBUG(if (Next->isMoveable()) {
dbgs() << "BOLT-DEBUG: setting " << *Next << " as unmoveable "
<< "due to ambiguous relocation (0x"
<< Twine::utohexstr(Address) << ") @ 0x"
<< Twine::utohexstr(Rel.getOffset()) << "\n";
});
Next->setIsMoveable(false);
}
}
};
// If we are allowing section relocations, we assign relocations
// that are pointing to the end of a symbol to that symbol rather
// than the following symbol.
@@ -2486,7 +2432,7 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
"up with symbol names referenced in the relocation");
if (!opts::AllowSectionRelocations && IsSectionRelocation) {
markAmbiguousRelocations(BD);
BC->markAmbiguousRelocations(*BD, Address);
}
ReferencedSymbol = BD->getSymbol();
@@ -2531,7 +2477,7 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
if (!opts::AllowSectionRelocations && IsSectionRelocation) {
auto *BD = BC->getBinaryDataByName(ReferencedSymbol->getName());
markAmbiguousRelocations(BD);
BC->markAmbiguousRelocations(*BD, Address);
}
}
}
@@ -2553,9 +2499,6 @@ void RewriteInstance::readRelocations(const SectionRef &Section,
NumDataRelocations < opts::MaxDataRelocations);
};
if (IsFromCode && IsAArch64)
ForceRelocation = true;
if ((RefSection && refersToReorderedSection(RefSection)) ||
(opts::ForceToDataRelocations && checkMaxDataRelocations()))
ForceRelocation = true;