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[BOLT] Fix debug info update for inlining. 

Summary:
When inlining, if a callee has debug info and a caller does not
(i.e. a containing compilation unit was compiled without "-g"), we try
to update a nonexistent compilation unit. Instead we should skip
updating debug info in such cases.

Minor refactoring of line number emitting code.

(cherry picked from FBD4823982)
This commit is contained in:
Maksim Panchenko 2017-04-03 16:24:26 -07:00
parent 0bde796e50
commit c166a8c1a7
2 changed files with 75 additions and 61 deletions
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106
bolt/BinaryFunction.cpp
View File

@ -2526,7 +2526,6 @@ void BinaryFunction::modifyLayout(LayoutType Type, bool MinBranchClusters,
}
void BinaryFunction::emitBody(MCStreamer &Streamer, bool EmitColdPart) {
auto ULT = getDWARFUnitLineTable();
int64_t CurrentGnuArgsSize = 0;
for (auto BB : layout()) {
if (EmitColdPart != BB->isCold())
@ -2536,14 +2535,9 @@ void BinaryFunction::emitBody(MCStreamer &Streamer, bool EmitColdPart) {
Streamer.EmitCodeAlignment(BB->getAlignment());
Streamer.EmitLabel(BB->getLabel());
// Remember last .debug_line entry emitted so that we don't repeat them in
// subsequent instructions, as gdb can figure it out by looking at the
// previous instruction with available line number info.
SMLoc LastLocSeen;
// Remember if last instruction emitted was a prefix
bool LastIsPrefix = false;
SMLoc LastLocSeen;
for (auto I = BB->begin(), E = BB->end(); I != E; ++I) {
auto &Instr = *I;
// Handle pseudo instructions.
@ -2558,52 +2552,8 @@ void BinaryFunction::emitBody(MCStreamer &Streamer, bool EmitColdPart) {
Streamer.EmitCFIInstruction(*getCFIFor(Instr));
continue;
}
if (opts::UpdateDebugSections) {
auto RowReference = DebugLineTableRowRef::fromSMLoc(Instr.getLoc());
if (RowReference != DebugLineTableRowRef::NULL_ROW &&
Instr.getLoc().getPointer() != LastLocSeen.getPointer()) {
auto Unit = ULT.first;
auto OriginalLineTable = ULT.second;
const auto OrigUnitID = Unit->getOffset();
unsigned NewFilenum = 0;
// If the CU id from the current instruction location does not
// match the CU id from the current function, it means that we
// have come across some inlined code. We must look up the CU
// for the instruction's original function and get the line table
// from that. We also update the current CU debug info with the
// filename of the inlined function.
if (RowReference.DwCompileUnitIndex != OrigUnitID) {
Unit = BC.DwCtx->
getCompileUnitForOffset(RowReference.DwCompileUnitIndex);
OriginalLineTable = BC.DwCtx->getLineTableForUnit(Unit);
const auto Filenum =
OriginalLineTable->Rows[RowReference.RowIndex - 1].File;
NewFilenum =
BC.addDebugFilenameToUnit(OrigUnitID,
RowReference.DwCompileUnitIndex,
Filenum);
}
assert(Unit && OriginalLineTable &&
"Invalid CU offset set in instruction debug info.");
const auto &OriginalRow =
OriginalLineTable->Rows[RowReference.RowIndex - 1];
BC.Ctx->setCurrentDwarfLoc(
NewFilenum == 0 ? OriginalRow.File : NewFilenum,
OriginalRow.Line,
OriginalRow.Column,
(DWARF2_FLAG_IS_STMT * OriginalRow.IsStmt) |
(DWARF2_FLAG_BASIC_BLOCK * OriginalRow.BasicBlock) |
(DWARF2_FLAG_PROLOGUE_END * OriginalRow.PrologueEnd) |
(DWARF2_FLAG_EPILOGUE_BEGIN * OriginalRow.EpilogueBegin),
OriginalRow.Isa,
OriginalRow.Discriminator);
BC.Ctx->setDwarfCompileUnitID(OrigUnitID);
LastLocSeen = Instr.getLoc();
}
if (opts::UpdateDebugSections && UnitLineTable.first) {
LastLocSeen = emitLineInfo(Instr.getLoc(), LastLocSeen);
}
// Emit GNU_args_size CFIs as necessary.
@ -3497,6 +3447,56 @@ bool BinaryFunction::isSymbolValidInScope(const SymbolRef &Symbol,
return true;
}
SMLoc BinaryFunction::emitLineInfo(SMLoc NewLoc, SMLoc PrevLoc) const {
auto *FunctionCU = UnitLineTable.first;
const auto *FunctionLineTable = UnitLineTable.second;
assert(FunctionCU && "cannot emit line info for function without CU");
auto RowReference = DebugLineTableRowRef::fromSMLoc(NewLoc);
// Check if no new line info needs to be emitted.
if (RowReference == DebugLineTableRowRef::NULL_ROW ||
NewLoc.getPointer() == PrevLoc.getPointer())
return PrevLoc;
unsigned CurrentFilenum = 0;
const auto *CurrentLineTable = FunctionLineTable;
// If the CU id from the current instruction location does not
// match the CU id from the current function, it means that we
// have come across some inlined code. We must look up the CU
// for the instruction's original function and get the line table
// from that.
const auto FunctionUnitIndex = FunctionCU->getOffset();
const auto CurrentUnitIndex = RowReference.DwCompileUnitIndex;
if (CurrentUnitIndex != FunctionUnitIndex) {
CurrentLineTable = BC.DwCtx->getLineTableForUnit(
BC.DwCtx->getCompileUnitForOffset(CurrentUnitIndex));
// Add filename from the inlined function to the current CU.
CurrentFilenum =
BC.addDebugFilenameToUnit(FunctionUnitIndex, CurrentUnitIndex,
CurrentLineTable->Rows[RowReference.RowIndex - 1].File);
}
const auto &CurrentRow = CurrentLineTable->Rows[RowReference.RowIndex - 1];
if (!CurrentFilenum)
CurrentFilenum = CurrentRow.File;
BC.Ctx->setCurrentDwarfLoc(
CurrentFilenum,
CurrentRow.Line,
CurrentRow.Column,
(DWARF2_FLAG_IS_STMT * CurrentRow.IsStmt) |
(DWARF2_FLAG_BASIC_BLOCK * CurrentRow.BasicBlock) |
(DWARF2_FLAG_PROLOGUE_END * CurrentRow.PrologueEnd) |
(DWARF2_FLAG_EPILOGUE_BEGIN * CurrentRow.EpilogueBegin),
CurrentRow.Isa,
CurrentRow.Discriminator);
BC.Ctx->setDwarfCompileUnitID(FunctionUnitIndex);
return NewLoc;
}
BinaryFunction::~BinaryFunction() {
for (auto BB : BasicBlocks) {
delete BB;

28
bolt/BinaryFunction.h
View File

@ -315,6 +315,12 @@ private:
std::vector<std::pair<const DWARFDebugInfoEntryMinimal *,
DWARFCompileUnit *>> SubprogramDIEs;
/// Line table for the function with containing compilation unit.
/// Because of identical code folding the function could have multiple
/// associated compilation units. The first of them with line number info
/// is referenced by UnitLineTable.
DWARFUnitLineTable UnitLineTable{nullptr, nullptr};
/// Offset of this function's address ranges in the .debug_ranges section of
/// the output binary.
uint32_t AddressRangesOffset{-1U};
@ -753,6 +759,12 @@ private:
unsigned Size,
uint64_t Offset);
/// Emit line number information corresponding to \p NewLoc. \p PrevLoc
/// provides a context for de-duplication of line number info.
///
/// Return new current location which is either \p NewLoc or \p PrevLoc.
SMLoc emitLineInfo(SMLoc NewLoc, SMLoc PrevLoc) const;
BinaryFunction& operator=(const BinaryFunction &) = delete;
BinaryFunction(const BinaryFunction &) = delete;
@ -1670,20 +1682,22 @@ public:
void addSubprogramDIE(DWARFCompileUnit *Unit,
const DWARFDebugInfoEntryMinimal *DIE) {
SubprogramDIEs.emplace_back(DIE, Unit);
if (!UnitLineTable.first) {
if (const auto *LineTable = BC.DwCtx->getLineTableForUnit(Unit)) {
UnitLineTable = std::make_pair(Unit, LineTable);
}
}
}
/// Return all compilation units with entry for this function.
/// Because of identical code folding there could be multiple of these.
const decltype(SubprogramDIEs) &getSubprogramDIEs() const {
return SubprogramDIEs;
}
/// Return DWARF compile unit with line info.
/// Return DWARF compile unit with line info for this function.
DWARFUnitLineTable getDWARFUnitLineTable() const {
for (auto &DIEUnitPair : SubprogramDIEs) {
if (auto *LT = BC.DwCtx->getLineTableForUnit(DIEUnitPair.second)) {
return std::make_pair(DIEUnitPair.second, LT);
}
}
return std::make_pair(nullptr, nullptr);
return UnitLineTable;
}
/// Returns the size of the basic block in the original binary.