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[BOLT] Emit sorted DWARF ranges and location lists.
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Summary:
When producing address ranges and location lists for debug info
add a post-processing step that sorts them and merges adjacent
entries.

Fix a memory allocation/free issue for .debug_ranges section.

(cherry picked from FBD5130583)
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@maksfb
maksfb committed May 24, 2017
1 parent 96943d2 commit 2e744e6
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Showing 3 changed files with 95 additions and 34 deletions.
104 changes: 79 additions & 25 deletions bolt/BinaryFunction.cpp
View file
Expand Up @@ -3773,14 +3773,15 @@ DWARFAddressRangesVector BinaryFunction::getOutputAddressRanges() const {
}

DWARFAddressRangesVector BinaryFunction::translateInputToOutputRanges(
DWARFAddressRangesVector InputRanges) const {
// If the function wasn't changed - there's nothing to update.
const DWARFAddressRangesVector &InputRanges) const {
// If the function hasn't changed return the same ranges.
if (!isEmitted() && !opts::Relocs)
return InputRanges;

DWARFAddressRangesVector OutputRanges;
// Even though we will merge ranges in a post-processing pass, we attempt to
// merge them in a main processing loop as it improves the processing time.
uint64_t PrevEndAddress = 0;

DWARFAddressRangesVector OutputRanges;
for (const auto &Range : InputRanges) {
if (!containsAddress(Range.first)) {
DEBUG(dbgs() << "BOLT-DEBUG: invalid debug address range detected for "
Expand All @@ -3790,10 +3791,16 @@ DWARFAddressRangesVector BinaryFunction::translateInputToOutputRanges(
continue;
}
auto InputOffset = Range.first - getAddress();
const auto InputEndOffset = Range.second - getAddress();
const auto InputEndOffset = std::min(Range.second - getAddress(), getSize());

auto BBI = std::upper_bound(BasicBlockOffsets.begin(),
BasicBlockOffsets.end(),
BasicBlockOffset(InputOffset, nullptr),
CompareBasicBlockOffsets());
--BBI;
do {
const auto *BB = getBasicBlockContainingOffset(InputOffset);
if (!BB) {
const auto *BB = BBI->second;
if (InputOffset < BB->getOffset() || InputOffset >= BB->getEndOffset()) {
DEBUG(dbgs() << "BOLT-DEBUG: invalid debug address range detected for "
<< *this << " : [0x" << Twine::utohexstr(Range.first)
<< ", 0x" << Twine::utohexstr(Range.second) << "]\n");
Expand All @@ -3809,24 +3816,40 @@ DWARFAddressRangesVector BinaryFunction::translateInputToOutputRanges(
EndAddress = StartAddress + InputEndOffset - InputOffset;

if (StartAddress == PrevEndAddress) {
OutputRanges.back().second = EndAddress;
OutputRanges.back().second = std::max(OutputRanges.back().second,
EndAddress);
} else {
OutputRanges.emplace_back(StartAddress, EndAddress);
OutputRanges.emplace_back(StartAddress,
std::max(StartAddress, EndAddress));
}
PrevEndAddress = EndAddress;
PrevEndAddress = OutputRanges.back().second;
}

InputOffset = BB->getEndOffset();
++BBI;
} while (InputOffset < InputEndOffset);
}

return OutputRanges;
// Post-processing pass to sort and merge ranges.
std::sort(OutputRanges.begin(), OutputRanges.end());
DWARFAddressRangesVector MergedRanges;
PrevEndAddress = 0;
for(const auto &Range : OutputRanges) {
if (Range.first <= PrevEndAddress) {
MergedRanges.back().second = std::max(MergedRanges.back().second,
Range.second);
} else {
MergedRanges.emplace_back(Range.first, Range.second);
}
PrevEndAddress = MergedRanges.back().second;
}

return MergedRanges;
}

DWARFDebugLoc::LocationList BinaryFunction::translateInputToOutputLocationList(
DWARFDebugLoc::LocationList &&InputLL,
const DWARFDebugLoc::LocationList &InputLL,
uint64_t BaseAddress) const {

// If the function wasn't changed - there's nothing to update.
if (!isEmitted() && !opts::Relocs) {
if (!BaseAddress) {
Expand All @@ -3841,24 +3864,28 @@ DWARFDebugLoc::LocationList BinaryFunction::translateInputToOutputLocationList(
}
}

DWARFDebugLoc::LocationList OutputLL;

uint64_t PrevEndAddress = 0;
SmallVectorImpl<unsigned char> *PrevLoc = nullptr;
DWARFDebugLoc::LocationList OutputLL;
for (auto &Entry : InputLL.Entries) {
const auto Start = Entry.Begin + BaseAddress;
const auto End = Entry.End + BaseAddress;
if (!containsAddress(Start)) {
DEBUG(dbgs() << "BOLT-DEBUG: invalid debug address range detected for "
<< *this << " : [0x" << Twine::utohexstr(Start)
<< ", 0x" << Twine::utohexstr(End) << "]\n");
PrevEndAddress = 0;
continue;
}
auto InputOffset = Start - getAddress();
const auto InputEndOffset = End - getAddress();
const auto InputEndOffset = std::min(End - getAddress(), getSize());
auto BBI = std::upper_bound(BasicBlockOffsets.begin(),
BasicBlockOffsets.end(),
BasicBlockOffset(InputOffset, nullptr),
CompareBasicBlockOffsets());
--BBI;
do {
const auto *BB = getBasicBlockContainingOffset(InputOffset);
if (!BB) {
const auto *BB = BBI->second;
if (InputOffset < BB->getOffset() || InputOffset >= BB->getEndOffset()) {
DEBUG(dbgs() << "BOLT-DEBUG: invalid debug address range detected for "
<< *this << " : [0x" << Twine::utohexstr(Start)
<< ", 0x" << Twine::utohexstr(End) << "]\n");
Expand All @@ -3873,21 +3900,48 @@ DWARFDebugLoc::LocationList BinaryFunction::translateInputToOutputLocationList(
if (InputEndOffset < BB->getEndOffset())
EndAddress = StartAddress + InputEndOffset - InputOffset;

if (StartAddress == PrevEndAddress) {
OutputLL.Entries.back().End = EndAddress;
if (StartAddress == PrevEndAddress && Entry.Loc == *PrevLoc) {
OutputLL.Entries.back().End = std::max(OutputLL.Entries.back().End,
EndAddress);
} else {
OutputLL.Entries.emplace_back(
DWARFDebugLoc::Entry{StartAddress,
EndAddress,
std::move(Entry.Loc)});
std::max(StartAddress, EndAddress),
Entry.Loc});
}
PrevEndAddress = EndAddress;
PrevEndAddress = OutputLL.Entries.back().End;
PrevLoc = &OutputLL.Entries.back().Loc;
}

++BBI;
InputOffset = BB->getEndOffset();
} while (InputOffset < InputEndOffset);
}

return OutputLL;
// Sort and merge adjacent entries with identical location.
std::stable_sort(OutputLL.Entries.begin(), OutputLL.Entries.end(),
[] (const DWARFDebugLoc::Entry &A, const DWARFDebugLoc::Entry &B) {
return A.Begin < B.Begin;
});
DWARFDebugLoc::LocationList MergedLL;
PrevEndAddress = 0;
PrevLoc = nullptr;
for(const auto &Entry : OutputLL.Entries) {
if (Entry.Begin <= PrevEndAddress && *PrevLoc == Entry.Loc) {
MergedLL.Entries.back().End = std::max(Entry.End,
MergedLL.Entries.back().End);;
} else {
const auto Begin = std::max(Entry.Begin, PrevEndAddress);
const auto End = std::max(Begin, Entry.End);
MergedLL.Entries.emplace_back(DWARFDebugLoc::Entry{Begin,
End,
Entry.Loc});
}
PrevEndAddress = MergedLL.Entries.back().End;
PrevLoc = &MergedLL.Entries.back().Loc;
}

return MergedLL;
}

void BinaryFunction::printLoopInfo(raw_ostream &OS) const {
Expand Down
11 changes: 8 additions & 3 deletions bolt/BinaryFunction.h
View file
Expand Up @@ -1821,12 +1821,17 @@ class BinaryFunction {
/// Return output address ranges for a function.
DWARFAddressRangesVector getOutputAddressRanges() const;

/// Take address ranges corresponding to the input binary and translate
/// them to address ranges in the output binary.
DWARFAddressRangesVector translateInputToOutputRanges(
DWARFAddressRangesVector InputRanges) const;
const DWARFAddressRangesVector &InputRanges) const;

/// \p BaseAddress to be applied to all addresses in \pInputLL.
/// Similar to translateInputToOutputRanges() but operates on location lists
/// and moves associated data to output location lists.
///
/// \p BaseAddress is applied to all addresses in \pInputLL.
DWARFDebugLoc::LocationList translateInputToOutputLocationList(
DWARFDebugLoc::LocationList &&InputLL,
const DWARFDebugLoc::LocationList &InputLL,
uint64_t BaseAddress) const;

virtual ~BinaryFunction();
Expand Down
14 changes: 8 additions & 6 deletions bolt/DWARFRewriter.cpp
View file
Expand Up @@ -169,8 +169,7 @@ void RewriteInstance::updateUnitDebugInfo(
assert(!LL.Entries.empty() && "location list cannot be empty");

const auto OutputLL = Function
->translateInputToOutputLocationList(std::move(LL),
Unit->getBaseAddress());
->translateInputToOutputLocationList(LL, Unit->getBaseAddress());
DEBUG(
if (OutputLL.Entries.empty()) {
dbgs() << "BOLT-DEBUG: location list translated to an empty one "
Expand Down Expand Up @@ -459,17 +458,20 @@ void RewriteInstance::finalizeDebugSections() {
}

auto RangesSectionContents = RangesSectionsWriter->finalize();
auto SectionSize = RangesSectionContents->size();
uint8_t *SectionData = new uint8_t[SectionSize];
memcpy(SectionData, RangesSectionContents->data(), SectionSize);
EFMM->NoteSectionInfo[".debug_ranges"] = SectionInfo(
reinterpret_cast<uint64_t>(RangesSectionContents->data()),
RangesSectionContents->size(),
reinterpret_cast<uint64_t>(SectionData),
SectionSize,
/*Alignment=*/1,
/*IsCode=*/false,
/*IsReadOnly=*/true,
/*IsLocal=*/false);

auto LocationListSectionContents = LocationListWriter->finalize();
const auto SectionSize = LocationListSectionContents->size();
uint8_t *SectionData = new uint8_t[SectionSize];
SectionSize = LocationListSectionContents->size();
SectionData = new uint8_t[SectionSize];
memcpy(SectionData, LocationListSectionContents->data(), SectionSize);
EFMM->NoteSectionInfo[".debug_loc"] = SectionInfo(
reinterpret_cast<uint64_t>(SectionData),
Expand Down

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