Revert "[DebugInfo] Add DWARF emission for DBG_VALUE_LIST"

This reverts commit 0da27ba.

This revision was causing an error on the sanitizer-x86_64-linux-autoconf build.

Author: SLTozer

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -918,6 +918,9 @@ static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
   OS << V->getName();
   OS << " <- ";
 
+  // The second operand is only an offset if it's an immediate.
+  bool MemLoc = MI->isIndirectDebugValue();
+  auto Offset = StackOffset::getFixed(MemLoc ? MI->getOperand(1).getImm() : 0);
   const DIExpression *Expr = MI->getDebugExpression();
   if (Expr->getNumElements()) {
     OS << '[';
@@ -931,71 +934,56 @@ static bool emitDebugValueComment(const MachineInstr *MI, AsmPrinter &AP) {
   }
 
   // Register or immediate value. Register 0 means undef.
-  for (const MachineOperand &Op : MI->debug_operands()) {
-    if (&Op != MI->debug_operands().begin())
-      OS << ", ";
-    switch (Op.getType()) {
-    case MachineOperand::MO_FPImmediate: {
-      APFloat APF = APFloat(Op.getFPImm()->getValueAPF());
-      if (Op.getFPImm()->getType()->isFloatTy()) {
-        OS << (double)APF.convertToFloat();
-      } else if (Op.getFPImm()->getType()->isDoubleTy()) {
-        OS << APF.convertToDouble();
-      } else {
-        // There is no good way to print long double.  Convert a copy to
-        // double.  Ah well, it's only a comment.
-        bool ignored;
-        APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
-                    &ignored);
-        OS << "(long double) " << APF.convertToDouble();
-      }
-      break;
-    }
-    case MachineOperand::MO_Immediate: {
-      OS << Op.getImm();
-      break;
+  if (MI->getDebugOperand(0).isFPImm()) {
+    APFloat APF = APFloat(MI->getDebugOperand(0).getFPImm()->getValueAPF());
+    if (MI->getDebugOperand(0).getFPImm()->getType()->isFloatTy()) {
+      OS << (double)APF.convertToFloat();
+    } else if (MI->getDebugOperand(0).getFPImm()->getType()->isDoubleTy()) {
+      OS << APF.convertToDouble();
+    } else {
+      // There is no good way to print long double.  Convert a copy to
+      // double.  Ah well, it's only a comment.
+      bool ignored;
+      APF.convert(APFloat::IEEEdouble(), APFloat::rmNearestTiesToEven,
+                  &ignored);
+      OS << "(long double) " << APF.convertToDouble();
     }
-    case MachineOperand::MO_CImmediate: {
-      Op.getCImm()->getValue().print(OS, false /*isSigned*/);
-      break;
+  } else if (MI->getDebugOperand(0).isImm()) {
+    OS << MI->getDebugOperand(0).getImm();
+  } else if (MI->getDebugOperand(0).isCImm()) {
+    MI->getDebugOperand(0).getCImm()->getValue().print(OS, false /*isSigned*/);
+  } else if (MI->getDebugOperand(0).isTargetIndex()) {
+    auto Op = MI->getDebugOperand(0);
+    OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
+    // NOTE: Want this comment at start of line, don't emit with AddComment.
+    AP.OutStreamer->emitRawComment(OS.str());
+    return true;
+  } else {
+    Register Reg;
+    if (MI->getDebugOperand(0).isReg()) {
+      Reg = MI->getDebugOperand(0).getReg();
+    } else {
+      assert(MI->getDebugOperand(0).isFI() && "Unknown operand type");
+      const TargetFrameLowering *TFI = AP.MF->getSubtarget().getFrameLowering();
+      Offset += TFI->getFrameIndexReference(
+          *AP.MF, MI->getDebugOperand(0).getIndex(), Reg);
+      MemLoc = true;
     }
-    case MachineOperand::MO_TargetIndex: {
-      OS << "!target-index(" << Op.getIndex() << "," << Op.getOffset() << ")";
+    if (Reg == 0) {
+      // Suppress offset, it is not meaningful here.
+      OS << "undef";
       // NOTE: Want this comment at start of line, don't emit with AddComment.
       AP.OutStreamer->emitRawComment(OS.str());
-      break;
-    }
-    case MachineOperand::MO_Register:
-    case MachineOperand::MO_FrameIndex: {
-      Register Reg;
-      Optional<StackOffset> Offset;
-      if (Op.isReg()) {
-        Reg = Op.getReg();
-      } else {
-        const TargetFrameLowering *TFI =
-            AP.MF->getSubtarget().getFrameLowering();
-        Offset = TFI->getFrameIndexReference(*AP.MF, Op.getIndex(), Reg);
-      }
-      if (!Reg) {
-        // Suppress offset, it is not meaningful here.
-        OS << "undef";
-        break;
-      }
-      // The second operand is only an offset if it's an immediate.
-      if (MI->isIndirectDebugValue())
-        Offset = StackOffset::getFixed(MI->getDebugOffset().getImm());
-      if (Offset)
-        OS << '[';
-      OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
-      if (Offset)
-        OS << '+' << Offset->getFixed() << ']';
-      break;
-    }
-    default:
-      llvm_unreachable("Unknown operand type");
+      return true;
     }
+    if (MemLoc)
+      OS << '[';
+    OS << printReg(Reg, AP.MF->getSubtarget().getRegisterInfo());
   }
 
+  if (MemLoc)
+    OS << '+' << Offset.getFixed() << ']';
+
   // NOTE: Want this comment at start of line, don't emit with AddComment.
   AP.OutStreamer->emitRawComment(OS.str());
   return true;

llvm/lib/CodeGen/AsmPrinter/DbgEntityHistoryCalculator.cpp

@@ -37,6 +37,22 @@ namespace {
 using EntryIndex = DbgValueHistoryMap::EntryIndex;
 }
 
+// If @MI is a DBG_VALUE with debug value described by a
+// defined register, returns the number of this register.
+// In the other case, returns 0.
+static Register isDescribedByReg(const MachineInstr &MI) {
+  assert(MI.isDebugValue());
+  assert(MI.getNumOperands() == 4);
+  // If the location of variable is an entry value (DW_OP_LLVM_entry_value)
+  // do not consider it as a register location.
+  if (MI.getDebugExpression()->isEntryValue())
+    return 0;
+  // If location of variable is described using a register (directly or
+  // indirectly), this register is always a first operand.
+  return MI.getDebugOperand(0).isReg() ? MI.getDebugOperand(0).getReg()
+                                       : Register();
+}
+
 void InstructionOrdering::initialize(const MachineFunction &MF) {
   // We give meta instructions the same ordinal as the preceding instruction
   // because this class is written for the task of comparing positions of
@@ -317,44 +333,24 @@ static void addRegDescribedVar(RegDescribedVarsMap &RegVars, unsigned RegNo,
 }
 
 /// Create a clobbering entry and end all open debug value entries
-/// for \p Var that are described by \p RegNo using that entry. Inserts into \p
-/// FellowRegisters the set of Registers that were also used to describe \p Var
-/// alongside \p RegNo.
+/// for \p Var that are described by \p RegNo using that entry.
 static void clobberRegEntries(InlinedEntity Var, unsigned RegNo,
                               const MachineInstr &ClobberingInstr,
                               DbgValueEntriesMap &LiveEntries,
-                              DbgValueHistoryMap &HistMap,
-                              SmallVectorImpl<Register> &FellowRegisters) {
+                              DbgValueHistoryMap &HistMap) {
   EntryIndex ClobberIndex = HistMap.startClobber(Var, ClobberingInstr);
+
   // Close all entries whose values are described by the register.
   SmallVector<EntryIndex, 4> IndicesToErase;
-  // If a given register appears in a live DBG_VALUE_LIST for Var alongside the
-  // clobbered register, and never appears in a live DBG_VALUE* for Var without
-  // the clobbered register, then it is no longer linked to the variable.
-  SmallSet<Register, 4> MaybeRemovedRegisters;
-  SmallSet<Register, 4> KeepRegisters;
   for (auto Index : LiveEntries[Var]) {
     auto &Entry = HistMap.getEntry(Var, Index);
     assert(Entry.isDbgValue() && "Not a DBG_VALUE in LiveEntries");
-    if (Entry.getInstr()->isDebugEntryValue())
-      continue;
-    if (Entry.getInstr()->hasDebugOperandForReg(RegNo)) {
+    if (isDescribedByReg(*Entry.getInstr()) == RegNo) {
       IndicesToErase.push_back(Index);
       Entry.endEntry(ClobberIndex);
-      for (auto &MO : Entry.getInstr()->debug_operands())
-        if (MO.isReg() && MO.getReg() && MO.getReg() != RegNo)
-          MaybeRemovedRegisters.insert(MO.getReg());
-    } else {
-      for (auto &MO : Entry.getInstr()->debug_operands())
-        if (MO.isReg() && MO.getReg())
-          KeepRegisters.insert(MO.getReg());
     }
   }
 
-  for (Register Reg : MaybeRemovedRegisters)
-    if (!KeepRegisters.contains(Reg))
-      FellowRegisters.push_back(Reg);
-
   // Drop all entries that have ended.
   for (auto Index : IndicesToErase)
     LiveEntries[Var].erase(Index);
@@ -382,24 +378,17 @@ static void handleNewDebugValue(InlinedEntity Var, const MachineInstr &DV,
         IndicesToErase.push_back(Index);
         Entry.endEntry(NewIndex);
       }
-      if (!DV.isDebugEntryValue())
-        for (const MachineOperand &Op : DV.debug_operands())
-          if (Op.isReg() && Op.getReg())
-            TrackedRegs[Op.getReg()] |= !Overlaps;
+      if (Register Reg = isDescribedByReg(DV))
+        TrackedRegs[Reg] |= !Overlaps;
     }
 
     // If the new debug value is described by a register, add tracking of
     // that register if it is not already tracked.
-    if (!DV.isDebugEntryValue()) {
-      for (const MachineOperand &Op : DV.debug_operands()) {
-        if (Op.isReg() && Op.getReg()) {
-          Register NewReg = Op.getReg();
-          if (!TrackedRegs.count(NewReg))
-            addRegDescribedVar(RegVars, NewReg, Var);
-          LiveEntries[Var].insert(NewIndex);
-          TrackedRegs[NewReg] = true;
-        }
-      }
+    if (Register NewReg = isDescribedByReg(DV)) {
+      if (!TrackedRegs.count(NewReg))
+        addRegDescribedVar(RegVars, NewReg, Var);
+      LiveEntries[Var].insert(NewIndex);
+      TrackedRegs[NewReg] = true;
     }
 
     // Drop tracking of registers that are no longer used.
@@ -422,16 +411,9 @@ static void clobberRegisterUses(RegDescribedVarsMap &RegVars,
                                 DbgValueEntriesMap &LiveEntries,
                                 const MachineInstr &ClobberingInstr) {
   // Iterate over all variables described by this register and add this
-  // instruction to their history, clobbering it. All registers that also
-  // describe the clobbered variables (i.e. in variadic debug values) will have
-  // those Variables removed from their DescribedVars.
-  for (const auto &Var : I->second) {
-    SmallVector<Register, 4> FellowRegisters;
-    clobberRegEntries(Var, I->first, ClobberingInstr, LiveEntries, HistMap,
-                      FellowRegisters);
-    for (Register RegNo : FellowRegisters)
-      dropRegDescribedVar(RegVars, RegNo, Var);
-  }
+  // instruction to their history, clobbering it.
+  for (const auto &Var : I->second)
+    clobberRegEntries(Var, I->first, ClobberingInstr, LiveEntries, HistMap);
   RegVars.erase(I);
 }
 

llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp

@@ -35,8 +35,7 @@ Optional<DbgVariableLocation>
 DbgVariableLocation::extractFromMachineInstruction(
     const MachineInstr &Instruction) {
   DbgVariableLocation Location;
-  // Variables calculated from multiple locations can't be represented here.
-  if (Instruction.getNumDebugOperands() != 1)
+  if (!Instruction.isDebugValue())
     return None;
   if (!Instruction.getDebugOperand(0).isReg())
     return None;
@@ -47,15 +46,6 @@ DbgVariableLocation::extractFromMachineInstruction(
   int64_t Offset = 0;
   const DIExpression *DIExpr = Instruction.getDebugExpression();
   auto Op = DIExpr->expr_op_begin();
-  // We can handle a DBG_VALUE_LIST iff it has exactly one location operand that
-  // appears exactly once at the start of the expression.
-  if (Instruction.isDebugValueList()) {
-    if (Instruction.getNumDebugOperands() == 1 &&
-        Op->getOp() == dwarf::DW_OP_LLVM_arg)
-      ++Op;
-    else
-      return None;
-  }
   while (Op != DIExpr->expr_op_end()) {
     switch (Op->getOp()) {
     case dwarf::DW_OP_constu: {
@@ -271,8 +261,7 @@ void DebugHandlerBase::beginFunction(const MachineFunction *MF) {
       continue;
 
     auto IsDescribedByReg = [](const MachineInstr *MI) {
-      return any_of(MI->debug_operands(),
-                    [](auto &MO) { return MO.isReg() && MO.getReg(); });
+      return MI->getDebugOperand(0).isReg() && MI->getDebugOperand(0).getReg();
     };
 
     // The first mention of a function argument gets the CurrentFnBegin label,