index f5b8dd79cd08de1c7aa0343d145a8b8f12a94148..454c10f180895d51f2865755a72e9d5444364727 100644 (file)
llvm_unreachable("Unexpected 3 operand DBG_VALUE instruction!");
}
+/// Determine whether two variable pieces overlap.
+static bool piecesOverlap(DIVariable P1, DIVariable P2) {
+ if (!P1.isVariablePiece() || !P2.isVariablePiece())
+ return true;
+ unsigned l1 = P1.getPieceOffset();
+ unsigned l2 = P2.getPieceOffset();
+ unsigned r1 = l1 + P1.getPieceSize();
+ unsigned r2 = l2 + P2.getPieceSize();
+ // True where [l1,r1[ and [r1,r2[ overlap.
+ return (l1 < r2) && (l2 < r1);
+}
+
+/// Build the location list for all DBG_VALUEs in the function that
+/// describe the same variable. If the ranges of several independent
+/// pieces of the same variable overlap partially, split them up and
+/// combine the ranges. The resulting DebugLocEntries are will have
+/// strict monotonically increasing begin addresses and will never
+/// overlap.
+//
+// Input:
+//
+// Ranges History [var, loc, piece ofs size]
+// 0 | [x, (reg0, piece 0, 32)]
+// 1 | | [x, (reg1, piece 32, 32)] <- IsPieceOfPrevEntry
+// 2 | | ...
+// 3 | [clobber reg0]
+// 4 [x, (mem, piece 0, 64)] <- overlapping with both previous pieces of x.
+//
+// Output:
+//
+// [0-1] [x, (reg0, piece 0, 32)]
+// [1-3] [x, (reg0, piece 0, 32), (reg1, piece 32, 32)]
+// [3-4] [x, (reg1, piece 32, 32)]
+// [4- ] [x, (mem, piece 0, 64)]
+void DwarfDebug::
+buildLocationList(SmallVectorImpl<DebugLocEntry> &DebugLoc,
+ const DbgValueHistoryMap::InstrRanges &Ranges,
+ DwarfCompileUnit *TheCU) {
+ typedef std::pair<DIVariable, DebugLocEntry::Value> Range;
+ SmallVector<Range, 4> OpenRanges;
+
+ for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
+ const MachineInstr *Begin = I->first;
+ const MachineInstr *End = I->second;
+ assert(Begin->isDebugValue() && "Invalid History entry");
+
+ // Check if a variable is inaccessible in this range.
+ if (!Begin->isDebugValue() ||
+ (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
+ !Begin->getOperand(0).getReg())) {
+ OpenRanges.clear();
+ continue;
+ }
+
+ // If this piece overlaps with any open ranges, truncate them.
+ DIVariable DIVar = Begin->getDebugVariable();
+ auto Last = std::remove_if(OpenRanges.begin(), OpenRanges.end(), [&](Range R){
+ return piecesOverlap(DIVar, R.first);
+ });
+ OpenRanges.erase(Last, OpenRanges.end());
+
+ const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
+ assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
+
+ const MCSymbol *EndLabel;
+ if (End != nullptr)
+ EndLabel = getLabelAfterInsn(End);
+ else if (std::next(I) == Ranges.end())
+ EndLabel = FunctionEndSym;
+ else
+ EndLabel = getLabelBeforeInsn(std::next(I)->first);
+ assert(EndLabel && "Forgot label after instruction ending a range!");
+
+ DEBUG(dbgs() << "DotDebugLoc: " << *Begin << "\n");
+
+ auto Value = getDebugLocValue(Begin);
+ DebugLocEntry Loc(StartLabel, EndLabel, Value, TheCU);
+ if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc)) {
+ // Add all values from still valid non-overlapping pieces.
+ for (auto Range : OpenRanges)
+ Loc.addValue(Range.second);
+ DebugLoc.push_back(std::move(Loc));
+ }
+ // Add this value to the list of open ranges.
+ if (DIVar.isVariablePiece())
+ OpenRanges.push_back(std::make_pair(DIVar, Value));
+
+ DEBUG(dbgs() << "Values:\n";
+ for (auto Value : DebugLoc.back().getValues())
+ Value.getVariable()->dump();
+ dbgs() << "-----\n");
+ }
+}
+
+
// Find variables for each lexical scope.
void
DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
if (!Scope)
continue;
- Processed.insert(DV);
+ Processed.insert(getEntireVariable(DV));
const MachineInstr *MInsn = Ranges.front().first;
assert(MInsn->isDebugValue() && "History must begin with debug value");
ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
@@ -1246,38 +1341,9 @@ DwarfDebug::collectVariableInfo(SmallPtrSet<const MDNode *, 16> &Processed) {
DebugLocList &LocList = DotDebugLocEntries.back();
LocList.Label =
Asm->GetTempSymbol("debug_loc", DotDebugLocEntries.size() - 1);
- SmallVector<DebugLocEntry, 4> &DebugLoc = LocList.List;
- for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
- const MachineInstr *Begin = I->first;
- const MachineInstr *End = I->second;
- assert(Begin->isDebugValue() && "Invalid History entry");
-
- // Check if a variable is unaccessible in this range.
- if (Begin->getNumOperands() > 1 && Begin->getOperand(0).isReg() &&
- !Begin->getOperand(0).getReg())
- continue;
- DEBUG(dbgs() << "DotDebugLoc Pair:\n" << "\t" << *Begin);
- if (End != nullptr)
- DEBUG(dbgs() << "\t" << *End);
- else
- DEBUG(dbgs() << "\tNULL\n");
-
- const MCSymbol *StartLabel = getLabelBeforeInsn(Begin);
- assert(StartLabel && "Forgot label before DBG_VALUE starting a range!");
-
- const MCSymbol *EndLabel;
- if (End != nullptr)
- EndLabel = getLabelAfterInsn(End);
- else if (std::next(I) == Ranges.end())
- EndLabel = FunctionEndSym;
- else
- EndLabel = getLabelBeforeInsn(std::next(I)->first);
- assert(EndLabel && "Forgot label after instruction ending a range!");
-
- DebugLocEntry Loc(StartLabel, EndLabel, getDebugLocValue(Begin), TheCU);
- if (DebugLoc.empty() || !DebugLoc.back().Merge(Loc))
- DebugLoc.push_back(std::move(Loc));
- }
+
+ // Build the location list for this variable.
+ buildLocationList(LocList.List, Ranges, TheCU);
}
// Collect info for variables that were optimized out.
// The first mention of a function argument gets the FunctionBeginSym
// label, so arguments are visible when breaking at function entry.
- DIVariable DV(I.first);
+ DIVariable DV(Ranges.front().first->getDebugVariable());
if (DV.isVariable() && DV.getTag() == dwarf::DW_TAG_arg_variable &&
- getDISubprogram(DV.getContext()).describes(MF->getFunction()))
- LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
+ getDISubprogram(DV.getContext()).describes(MF->getFunction())) {
+ if (!DV.isVariablePiece())
+ LabelsBeforeInsn[Ranges.front().first] = FunctionBeginSym;
+ else {
+ // Mark all non-overlapping initial pieces.
+ for (auto I = Ranges.begin(); I != Ranges.end(); ++I) {
+ DIVariable Piece = I->first->getDebugVariable();
+ if (std::all_of(Ranges.begin(), I,
+ [&](DbgValueHistoryMap::InstrRange Pred){
+ return !piecesOverlap(Piece, Pred.first->getDebugVariable());
+ }))
+ LabelsBeforeInsn[I->first] = FunctionBeginSym;
+ else
+ break;
+ }
+ }
+ }
for (const auto &Range : Ranges) {
requestLabelBeforeInsn(Range.first);
Holder.emitStrings(Asm->getObjFileLowering().getDwarfStrSection());
}
+/// Emits an optimal (=sorted) sequence of DW_OP_pieces.
+void DwarfDebug::emitLocPieces(ByteStreamer &Streamer,
+ const DITypeIdentifierMap &Map,
+ ArrayRef<DebugLocEntry::Value> Values) {
+ typedef DebugLocEntry::Value Piece;
+ SmallVector<Piece, 4> Pieces(Values.begin(), Values.end());
+ assert(std::all_of(Pieces.begin(), Pieces.end(), [](Piece &P) {
+ return DIVariable(P.getVariable()).isVariablePiece();
+ }) && "all values are expected to be pieces");
+
+ // Sort the pieces so they can be emitted using DW_OP_piece.
+ std::sort(Pieces.begin(), Pieces.end(), [](const Piece &A, const Piece &B) {
+ DIVariable VarA(A.getVariable());
+ DIVariable VarB(B.getVariable());
+ return VarA.getPieceOffset() < VarB.getPieceOffset();
+ });
+ // Remove any duplicate entries by dropping all but the first.
+ Pieces.erase(std::unique(Pieces.begin(), Pieces.end(),
+ [] (const Piece &A,const Piece &B){
+ return A.getVariable() == B.getVariable();
+ }), Pieces.end());
+
+ unsigned Offset = 0;
+ for (auto Piece : Pieces) {
+ DIVariable Var(Piece.getVariable());
+ unsigned PieceOffset = Var.getPieceOffset();
+ unsigned PieceSize = Var.getPieceSize();
+ assert(Offset <= PieceOffset && "overlapping pieces in DebugLocEntry");
+ if (Offset < PieceOffset) {
+ // The DWARF spec seriously mandates pieces with no locations for gaps.
+ Asm->EmitDwarfOpPiece(Streamer, (PieceOffset-Offset)*8);
+ Offset += PieceOffset-Offset;
+ }
+
+ Offset += PieceSize;
+
+ const unsigned SizeOfByte = 8;
+ assert(!Var.isIndirect() && "indirect address for piece");
+#ifndef NDEBUG
+ unsigned VarSize = Var.getSizeInBits(Map);
+ assert(PieceSize+PieceOffset <= VarSize/SizeOfByte
+ && "piece is larger than or outside of variable");
+ assert(PieceSize*SizeOfByte != VarSize
+ && "piece covers entire variable");
+#endif
+ if (Piece.isLocation() && Piece.getLoc().isReg())
+ Asm->EmitDwarfRegOpPiece(Streamer,
+ Piece.getLoc(),
+ PieceSize*SizeOfByte);
+ else {
+ emitDebugLocValue(Streamer, Piece);
+ Asm->EmitDwarfOpPiece(Streamer, PieceSize*SizeOfByte);
+ }
+ }
+}
+
+
void DwarfDebug::emitDebugLocEntry(ByteStreamer &Streamer,
const DebugLocEntry &Entry) {
- assert(Entry.getValues().size() == 1 &&
- "multi-value entries are not supported yet.");
const DebugLocEntry::Value Value = Entry.getValues()[0];
DIVariable DV(Value.getVariable());
+ if (DV.isVariablePiece())
+ // Emit all pieces that belong to the same variable and range.
+ return emitLocPieces(Streamer, TypeIdentifierMap, Entry.getValues());
+
+ assert(Entry.getValues().size() == 1 && "only pieces may have >1 value");
+ emitDebugLocValue(Streamer, Value);
+}
+
+void DwarfDebug::emitDebugLocValue(ByteStreamer &Streamer,
+ const DebugLocEntry::Value &Value) {
+ DIVariable DV(Value.getVariable());
+ // Regular entry.
if (Value.isInt()) {
DIBasicType BTy(resolve(DV.getType()));
if (BTy.Verify() && (BTy.getEncoding() == dwarf::DW_ATE_signed ||
} else if (Element == DIBuilder::OpDeref) {
if (!Loc.isReg())
Streamer.EmitInt8(dwarf::DW_OP_deref, "DW_OP_deref");
+ } else if (Element == DIBuilder::OpPiece) {
+ i += 3;
+ // handled in emitDebugLocEntry.
} else
llvm_unreachable("unknown Opcode found in complex address");
}