[llvm] r327303 - [SelectionDAG] Improve handling of dangling debug info

Adrian Prantl via llvm-commits llvm-commits at lists.llvm.org
Thu Mar 29 11:15:34 PDT 2018



> On Mar 29, 2018, at 11:07 AM, David Blaikie <dblaikie at gmail.com> wrote:
> 
> OK - so that seems like we're getting some variables with really small ranges, perhaps? Not that they are necessarily wrong but maybe worth looking at a sampling of the variables added by this change to see if they're correct/reasonable/worth having?
> 
> Seems like a big enough swing that it'd be worth the extra validation?
> 
> - Dave
> 
> On Thu, Mar 29, 2018 at 10:37 AM Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
> I think you are right. I looked at the Statistics.cpp code and "source variables" means source variables with a DW_AT_locations or DW_AT_constant_value.

I think I didn't look closely enough: there are two metrics: "source variables" is supposed to be counting the number of unique variables regardless of location and "variables with location" is the subset that has a location. But the unique variables are indexed by DIE offset (instead of by DIE offset of their abstract origin or somehting), so inlined instances of variables with a location aren't uniqued with their abstract origin and are thus counted multiple times. That's a bug in dwarfdump. So what we are seeing here is more inlined variables that previously didn't have a location.

> 
> -- adrian
> 
> 
>> On Mar 29, 2018, at 10:23 AM, David Blaikie <dblaikie at gmail.com <mailto:dblaikie at gmail.com>> wrote:
>> 
>> But that shouldn't cause the DW_TAG_variable to not be present, right? we keep all the variables in the "variables" list off the subprogram to emit even in the case of optimizations eliminating a variable (then the variable is emitted, but without any DW_AT_location) - that was my understanding.
>> 
>> On Thu, Mar 29, 2018 at 10:11 AM Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
>> 
>>> On Mar 29, 2018, at 10:00 AM, David Blaikie <dblaikie at gmail.com <mailto:dblaikie at gmail.com>> wrote:
>>> 
>>> 
>>> 
>>> On Thu, Mar 29, 2018 at 9:09 AM Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
>>> 
>>>> On Mar 29, 2018, at 9:02 AM, David Blaikie <dblaikie at gmail.com <mailto:dblaikie at gmail.com>> wrote:
>>>> 
>>>> Seeing about a 7.5% increase in (compressed) debug_loc (and 4.2% increase in debug_info) in one binary at Google.
>>> 
>>> So I guess this is ... good news?
>>> 
>>>> 
>>>> I haven't looked into it further - if you all think this is expected (an increase in debug location accuracy/granularity/etc would account for this sort of growth), I'm OK with it.
>>>> 
>>>> If useful, I can look into some samples further - or you can (assuming an optimized Clang shows similar growth - I haven't checked yet).
>>> 
>>> Would it be easy for you to run llvm-dwarfdump --statistics on before and after? That might tell us how many more variables are visible for the extra cost in size.
>>> 
>>> Sure, in both cases llvm-dwarfdump printed:
>>> 
>>> Location list overflows the debug_loc section.
>>> error: failed to consume entire .debug_loc section
>>> 
>>> The % improvements:
>>> 
>>> Source functions: 0%
>>> Inlined functions: 0%
>>> Unique source variables: 11.19%
>>> Source variables: 357.78%
>>> Variables with locations: 15.09%
>>> Scope bytes total: 8.39%
>>> Scope bytes covered: 16.87%
>>> 
>>> So what does the "source variables" mean? Changes to optimizations shouldn't increase the number of variables we put in the DWARF, right? (that's why there's the "variables" list off the subprogram - to keep track of variables even if they're totally optimized away)
>> 
>> dwarfdump has no way of knowing what variables *should* be in the debug info, so if this patch added new DBG_VALUEs that were previously being dropped, we can see an increase in variables that were previously missing entirely because the only DBG_VALUE describing them was dropped by SDag.
>> 
>> -- adrian
>>> 
>>>> 
>>>> On Mon, Mar 12, 2018 at 11:05 AM Bjorn Pettersson via llvm-commits <llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>> wrote:
>>>> Author: bjope
>>>> Date: Mon Mar 12 11:02:39 2018
>>>> New Revision: 327303
>>>> 
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=327303&view=rev <http://llvm.org/viewvc/llvm-project?rev=327303&view=rev>
>>>> Log:
>>>> [SelectionDAG] Improve handling of dangling debug info
>>>> 
>>>> Summary:
>>>> 1) Make sure to discard dangling debug info if the variable (or
>>>> variable fragment) is mapped to something new before we had a
>>>> chance to resolve the dangling debug info.
>>>> 
>>>> 2) When resolving debug info, make sure to bump the associated
>>>> SDNodeOrder to ensure that the DBG_VALUE is emitted after the
>>>> instruction that defines the value used in the DBG_VALUE.
>>>> This will avoid a debug-use before def scenario as seen in
>>>> https://bugs.llvm.org/show_bug.cgi?id=36417 <https://bugs.llvm.org/show_bug.cgi?id=36417>.
>>>> 
>>>> The new test case, test/DebugInfo/X86/sdag-dangling-dbgvalue.ll,
>>>> show some other limitations in how dangling debug info is
>>>> handled in the SelectionDAG. Since we currently only support
>>>> having one dangling dbg.value per Value, we will end up dropping
>>>> debug info when there are more than one variable that is described
>>>> by the same "dangling value".
>>>> 
>>>> Reviewers: aprantl
>>>> 
>>>> Reviewed By: aprantl
>>>> 
>>>> Subscribers: aprantl, eraman, llvm-commits, JDevlieghere
>>>> 
>>>> Tags: #debug-info
>>>> 
>>>> Differential Revision: https://reviews.llvm.org/D44369 <https://reviews.llvm.org/D44369>
>>>> 
>>>> Added:
>>>>     llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll
>>>> Modified:
>>>>     llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
>>>>     llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
>>>>     llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
>>>>     llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h
>>>>     llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
>>>>     llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>>>>     llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
>>>>     llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll
>>>> 
>>>> Modified: llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DebugInfoMetadata.h?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DebugInfoMetadata.h?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/include/llvm/IR/DebugInfoMetadata.h (original)
>>>> +++ llvm/trunk/include/llvm/IR/DebugInfoMetadata.h Mon Mar 12 11:02:39 2018
>>>> @@ -2415,6 +2415,32 @@ public:
>>>>    static Optional<DIExpression *>
>>>>    createFragmentExpression(const DIExpression *Expr, unsigned OffsetInBits,
>>>>                             unsigned SizeInBits);
>>>> +
>>>> +  /// Determine the relative position of the fragments described by this
>>>> +  /// DIExpression and \p Other.
>>>> +  /// Returns -1 if this is entirely before Other, 0 if this and Other overlap,
>>>> +  /// 1 if this is entirely after Other.
>>>> +  int fragmentCmp(const DIExpression *Other) const {
>>>> +    auto Fragment1 = *getFragmentInfo();
>>>> +    auto Fragment2 = *Other->getFragmentInfo();
>>>> +    unsigned l1 = Fragment1.OffsetInBits;
>>>> +    unsigned l2 = Fragment2.OffsetInBits;
>>>> +    unsigned r1 = l1 + Fragment1.SizeInBits;
>>>> +    unsigned r2 = l2 + Fragment2.SizeInBits;
>>>> +    if (r1 <= l2)
>>>> +      return -1;
>>>> +    else if (r2 <= l1)
>>>> +      return 1;
>>>> +    else
>>>> +      return 0;
>>>> +  }
>>>> +
>>>> +  /// Check if fragments overlap between this DIExpression and \p Other.
>>>> +  bool fragmentsOverlap(const DIExpression *Other) const {
>>>> +    if (!isFragment() || !Other->isFragment())
>>>> +      return true;
>>>> +    return fragmentCmp(Other) == 0;
>>>> +  }
>>>>  };
>>>> 
>>>>  /// Global variables.
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Mon Mar 12 11:02:39 2018
>>>> @@ -1107,7 +1107,7 @@ void CodeViewDebug::calculateRanges(
>>>>        auto J = std::next(I);
>>>>        const DIExpression *DIExpr = DVInst->getDebugExpression();
>>>>        while (J != E &&
>>>> -             !fragmentsOverlap(DIExpr, J->first->getDebugExpression()))
>>>> +             !DIExpr->fragmentsOverlap(J->first->getDebugExpression()))
>>>>          ++J;
>>>>        if (J != E)
>>>>          End = getLabelBeforeInsn(J->first);
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp Mon Mar 12 11:02:39 2018
>>>> @@ -123,29 +123,6 @@ MCSymbol *DebugHandlerBase::getLabelAfte
>>>>    return LabelsAfterInsn.lookup(MI);
>>>>  }
>>>> 
>>>> -int DebugHandlerBase::fragmentCmp(const DIExpression *P1,
>>>> -                                  const DIExpression *P2) {
>>>> -  auto Fragment1 = *P1->getFragmentInfo();
>>>> -  auto Fragment2 = *P2->getFragmentInfo();
>>>> -  unsigned l1 = Fragment1.OffsetInBits;
>>>> -  unsigned l2 = Fragment2.OffsetInBits;
>>>> -  unsigned r1 = l1 + Fragment1.SizeInBits;
>>>> -  unsigned r2 = l2 + Fragment2.SizeInBits;
>>>> -  if (r1 <= l2)
>>>> -    return -1;
>>>> -  else if (r2 <= l1)
>>>> -    return 1;
>>>> -  else
>>>> -    return 0;
>>>> -}
>>>> -
>>>> -bool DebugHandlerBase::fragmentsOverlap(const DIExpression *P1,
>>>> -                                        const DIExpression *P2) {
>>>> -  if (!P1->isFragment() || !P2->isFragment())
>>>> -    return true;
>>>> -  return fragmentCmp(P1, P2) == 0;
>>>> -}
>>>> -
>>>>  /// If this type is derived from a base type then return base type size.
>>>>  uint64_t DebugHandlerBase::getBaseTypeSize(const DITypeRef TyRef) {
>>>>    DIType *Ty = TyRef.resolve();
>>>> @@ -232,8 +209,8 @@ void DebugHandlerBase::beginFunction(con
>>>>            const DIExpression *Fragment = I->first->getDebugExpression();
>>>>            if (std::all_of(Ranges.begin(), I,
>>>>                            [&](DbgValueHistoryMap::InstrRange Pred) {
>>>> -                            return !fragmentsOverlap(
>>>> -                                Fragment, Pred.first->getDebugExpression());
>>>> +                            return !Fragment->fragmentsOverlap(
>>>> +                                Pred.first->getDebugExpression());
>>>>                            }))
>>>>              LabelsBeforeInsn[I->first] = Asm->getFunctionBegin();
>>>>            else
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h (original)
>>>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DebugHandlerBase.h Mon Mar 12 11:02:39 2018
>>>> @@ -122,14 +122,6 @@ public:
>>>>    /// Return Label immediately following the instruction.
>>>>    MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
>>>> 
>>>> -  /// Determine the relative position of the fragments described by P1 and P2.
>>>> -  /// Returns -1 if P1 is entirely before P2, 0 if P1 and P2 overlap, 1 if P1 is
>>>> -  /// entirely after P2.
>>>> -  static int fragmentCmp(const DIExpression *P1, const DIExpression *P2);
>>>> -
>>>> -  /// Determine whether two variable fragments overlap.
>>>> -  static bool fragmentsOverlap(const DIExpression *P1, const DIExpression *P2);
>>>> -
>>>>    /// If this type is derived from a base type then return base type size.
>>>>    static uint64_t getBaseTypeSize(const DITypeRef TyRef);
>>>>  };
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Mar 12 11:02:39 2018
>>>> @@ -919,8 +919,7 @@ bool DebugLocEntry::MergeValues(const De
>>>>      // sorted.
>>>>      for (unsigned i = 0, j = 0; i < Values.size(); ++i) {
>>>>        for (; j < Next.Values.size(); ++j) {
>>>> -        int res = DebugHandlerBase::fragmentCmp(
>>>> -            cast<DIExpression>(Values[i].Expression),
>>>> +        int res = cast<DIExpression>(Values[i].Expression)->fragmentCmp(
>>>>              cast<DIExpression>(Next.Values[j].Expression));
>>>>          if (res == 0) // The two expressions overlap, we can't merge.
>>>>            return false;
>>>> @@ -983,7 +982,7 @@ DwarfDebug::buildLocationList(SmallVecto
>>>>      // If this fragment overlaps with any open ranges, truncate them.
>>>>      const DIExpression *DIExpr = Begin->getDebugExpression();
>>>>      auto Last = remove_if(OpenRanges, [&](DebugLocEntry::Value R) {
>>>> -      return fragmentsOverlap(DIExpr, R.getExpression());
>>>> +      return DIExpr->fragmentsOverlap(R.getExpression());
>>>>      });
>>>>      OpenRanges.erase(Last, OpenRanges.end());
>>>> 
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Mon Mar 12 11:02:39 2018
>>>> @@ -12,6 +12,7 @@
>>>>  //===----------------------------------------------------------------------===//
>>>> 
>>>>  #include "SelectionDAGBuilder.h"
>>>> +#include "SDNodeDbgValue.h"
>>>>  #include "llvm/ADT/APFloat.h"
>>>>  #include "llvm/ADT/APInt.h"
>>>>  #include "llvm/ADT/ArrayRef.h"
>>>> @@ -1077,29 +1078,64 @@ void SelectionDAGBuilder::visit(unsigned
>>>>    }
>>>>  }
>>>> 
>>>> +void SelectionDAGBuilder::dropDanglingDebugInfo(const DILocalVariable *Variable,
>>>> +                                                const DIExpression *Expr) {
>>>> +  SmallVector<const Value *, 4> ToRemove;
>>>> +  for (auto &DMI : DanglingDebugInfoMap) {
>>>> +    DanglingDebugInfo &DDI = DMI.second;
>>>> +    if (DDI.getDI()) {
>>>> +      const DbgValueInst *DI = DDI.getDI();
>>>> +      DIVariable *DanglingVariable = DI->getVariable();
>>>> +      DIExpression *DanglingExpr = DI->getExpression();
>>>> +      if (DanglingVariable == Variable &&
>>>> +          Expr->fragmentsOverlap(DanglingExpr)) {
>>>> +        DEBUG(dbgs() << "Dropping dangling debug info for " << *DI << "\n");
>>>> +        ToRemove.push_back(DMI.first);
>>>> +      }
>>>> +    }
>>>> +  }
>>>> +
>>>> +  for (auto V : ToRemove)
>>>> +    DanglingDebugInfoMap[V] = DanglingDebugInfo();
>>>> +}
>>>> +
>>>>  // resolveDanglingDebugInfo - if we saw an earlier dbg_value referring to V,
>>>>  // generate the debug data structures now that we've seen its definition.
>>>>  void SelectionDAGBuilder::resolveDanglingDebugInfo(const Value *V,
>>>>                                                     SDValue Val) {
>>>>    DanglingDebugInfo &DDI = DanglingDebugInfoMap[V];
>>>> -  if (DDI.getDI()) {
>>>> -    const DbgValueInst *DI = DDI.getDI();
>>>> -    DebugLoc dl = DDI.getdl();
>>>> -    unsigned DbgSDNodeOrder = DDI.getSDNodeOrder();
>>>> -    DILocalVariable *Variable = DI->getVariable();
>>>> -    DIExpression *Expr = DI->getExpression();
>>>> -    assert(Variable->isValidLocationForIntrinsic(dl) &&
>>>> -           "Expected inlined-at fields to agree");
>>>> -    SDDbgValue *SDV;
>>>> -    if (Val.getNode()) {
>>>> -      if (!EmitFuncArgumentDbgValue(V, Variable, Expr, dl, false, Val)) {
>>>> -        SDV = getDbgValue(Val, Variable, Expr, dl, DbgSDNodeOrder);
>>>> -        DAG.AddDbgValue(SDV, Val.getNode(), false);
>>>> -      }
>>>> +  if (!DDI.getDI())
>>>> +    return;
>>>> +  const DbgValueInst *DI = DDI.getDI();
>>>> +  DebugLoc dl = DDI.getdl();
>>>> +  unsigned ValSDNodeOrder = Val.getNode()->getIROrder();
>>>> +  unsigned DbgSDNodeOrder = DDI.getSDNodeOrder();
>>>> +  DILocalVariable *Variable = DI->getVariable();
>>>> +  DIExpression *Expr = DI->getExpression();
>>>> +  assert(Variable->isValidLocationForIntrinsic(dl) &&
>>>> +         "Expected inlined-at fields to agree");
>>>> +  SDDbgValue *SDV;
>>>> +  if (Val.getNode()) {
>>>> +    if (!EmitFuncArgumentDbgValue(V, Variable, Expr, dl, false, Val)) {
>>>> +      DEBUG(dbgs() << "Resolve dangling debug info [order=" << DbgSDNodeOrder
>>>> +            << "] for:\n  " << *DI << "\n");
>>>> +      DEBUG(dbgs() << "  By mapping to:\n    "; Val.dump());
>>>> +      // Increase the SDNodeOrder for the DbgValue here to make sure it is
>>>> +      // inserted after the definition of Val when emitting the instructions
>>>> +      // after ISel. An alternative could be to teach
>>>> +      // ScheduleDAGSDNodes::EmitSchedule to delay the insertion properly.
>>>> +      DEBUG(if (ValSDNodeOrder > DbgSDNodeOrder)
>>>> +              dbgs() << "changing SDNodeOrder from " << DbgSDNodeOrder
>>>> +                     << " to " << ValSDNodeOrder << "\n");
>>>> +      SDV = getDbgValue(Val, Variable, Expr, dl,
>>>> +                        std::max(DbgSDNodeOrder, ValSDNodeOrder));
>>>> +      DAG.AddDbgValue(SDV, Val.getNode(), false);
>>>>      } else
>>>> -      DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
>>>> -    DanglingDebugInfoMap[V] = DanglingDebugInfo();
>>>> -  }
>>>> +      DEBUG(dbgs() << "Resolved dangling debug info for " << *DI
>>>> +            << "in EmitFuncArgumentDbgValue\n");
>>>> +  } else
>>>> +    DEBUG(dbgs() << "Dropping debug info for " << *DI << "\n");
>>>> +  DanglingDebugInfoMap[V] = DanglingDebugInfo();
>>>>  }
>>>> 
>>>>  /// getCopyFromRegs - If there was virtual register allocated for the value V
>>>> @@ -5178,6 +5214,7 @@ SelectionDAGBuilder::visitIntrinsicCall(
>>>>      const DbgInfoIntrinsic &DI = cast<DbgInfoIntrinsic>(I);
>>>>      DILocalVariable *Variable = DI.getVariable();
>>>>      DIExpression *Expression = DI.getExpression();
>>>> +    dropDanglingDebugInfo(Variable, Expression);
>>>>      assert(Variable && "Missing variable");
>>>> 
>>>>      // Check if address has undef value.
>>>> @@ -5209,10 +5246,11 @@ SelectionDAGBuilder::visitIntrinsicCall(
>>>>      // DBG_VALUE instructions. llvm.dbg.declare is handled as a frame index in
>>>>      // the MachineFunction variable table.
>>>>      if (FI != std::numeric_limits<int>::max()) {
>>>> -      if (Intrinsic == Intrinsic::dbg_addr)
>>>> -        DAG.AddDbgValue(DAG.getFrameIndexDbgValue(Variable, Expression, FI, dl,
>>>> -                                                  SDNodeOrder),
>>>> -                        getRoot().getNode(), isParameter);
>>>> +      if (Intrinsic == Intrinsic::dbg_addr) {
>>>> +         SDDbgValue *SDV = DAG.getFrameIndexDbgValue(Variable, Expression,
>>>> +                                                     FI, dl, SDNodeOrder);
>>>> +         DAG.AddDbgValue(SDV, getRoot().getNode(), isParameter);
>>>> +      }
>>>>        return nullptr;
>>>>      }
>>>> 
>>>> @@ -5256,6 +5294,7 @@ SelectionDAGBuilder::visitIntrinsicCall(
>>>> 
>>>>      DILocalVariable *Variable = DI.getVariable();
>>>>      DIExpression *Expression = DI.getExpression();
>>>> +    dropDanglingDebugInfo(Variable, Expression);
>>>>      const Value *V = DI.getValue();
>>>>      if (!V)
>>>>        return nullptr;
>>>> @@ -5280,6 +5319,12 @@ SelectionDAGBuilder::visitIntrinsicCall(
>>>>        return nullptr;
>>>>      }
>>>> 
>>>> +    // TODO: When we get here we will either drop the dbg.value completely, or
>>>> +    // we try to move it forward by letting it dangle for awhile. So we should
>>>> +    // probably add an extra DbgValue to the DAG here, with a reference to
>>>> +    // "noreg", to indicate that we have lost the debug location for the
>>>> +    // variable.
>>>> +
>>>>      if (!V->use_empty() ) {
>>>>        // Do not call getValue(V) yet, as we don't want to generate code.
>>>>        // Remember it for later.
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h (original)
>>>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h Mon Mar 12 11:02:39 2018
>>>> @@ -671,6 +671,12 @@ public:
>>>>    /// emit CopyFromReg of the specified type Ty. Return empty SDValue() otherwise.
>>>>    SDValue getCopyFromRegs(const Value *V, Type *Ty);
>>>> 
>>>> +  /// If we have dangling debug info that describes \p Variable, or an
>>>> +  /// overlapping part of variable considering the \p Expr, then this method
>>>> +  /// weill drop that debug info as it isn't valid any longer.
>>>> +  void dropDanglingDebugInfo(const DILocalVariable *Variable,
>>>> +                             const DIExpression *Expr);
>>>> +
>>>>    // resolveDanglingDebugInfo - if we saw an earlier dbg_value referring to V,
>>>>    // generate the debug data structures now that we've seen its definition.
>>>>    void resolveDanglingDebugInfo(const Value *V, SDValue Val);
>>>> 
>>>> Modified: llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll?rev=327303&r1=327302&r2=327303&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll?rev=327303&r1=327302&r2=327303&view=diff>
>>>> ==============================================================================
>>>> --- llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll (original)
>>>> +++ llvm/trunk/test/DebugInfo/X86/dbg-value-inlined-parameter.ll Mon Mar 12 11:02:39 2018
>>>> @@ -32,10 +32,10 @@
>>>>  ;CHECK-NEXT: DW_AT_call_line
>>>> 
>>>>  ;CHECK: DW_TAG_formal_parameter
>>>> +;FIXME: Linux shouldn't drop this parameter either...
>>>>  ;CHECK-NOT: DW_TAG
>>>> -;FIXME: Shouldn't drop this parameter...
>>>> -;XCHECK:   DW_AT_abstract_origin {{.*}} "sp"
>>>> -;XCHECK: DW_TAG_formal_parameter
>>>> +;DARWIN:   DW_AT_abstract_origin {{.*}} "sp"
>>>> +;DARWIN: DW_TAG_formal_parameter
>>>>  ;CHECK: DW_AT_abstract_origin {{.*}} "nums"
>>>>  ;CHECK-NOT: DW_TAG_formal_parameter
>>>> 
>>>> 
>>>> Added: llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll?rev=327303&view=auto <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll?rev=327303&view=auto>
>>>> ==============================================================================
>>>> --- llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll (added)
>>>> +++ llvm/trunk/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll Mon Mar 12 11:02:39 2018
>>>> @@ -0,0 +1,201 @@
>>>> +; RUN: llc %s -stop-before expand-isel-pseudos -o - | FileCheck %s
>>>> +
>>>> +;--------------------------------------------------------------------
>>>> +; This test case is basically generated from the following C code.
>>>> +; Compiled with "--target=x86_64-apple-darwin -S -g -O3" to get debug
>>>> +; info for optimized code.
>>>> +;
>>>> +; struct SS {
>>>> +;   int a;
>>>> +;   int b;
>>>> +; } S = { .a = 23, .b = -17 };
>>>> +;
>>>> +; int test1() {
>>>> +;   struct SS* foo1 = &S;
>>>> +;   return (int)foo1;
>>>> +; }
>>>> +;
>>>> +; int test2() {
>>>> +;   struct SS* foo2 = &S;
>>>> +;   struct SS* bar2 = &S;
>>>> +;   return (int)foo2 + (int)bar2;
>>>> +; }
>>>> +;
>>>> +; int test3() {
>>>> +;   struct SS* bar3 = &S;
>>>> +;   struct SS* foo3 = &S;
>>>> +;   return (int)foo3 + (int)bar3;
>>>> +; }
>>>> +;
>>>> +; int test4() {
>>>> +;   struct SS* foo4 = &S;
>>>> +;   struct SS* bar4 = &S;
>>>> +;   foo = 0;
>>>> +;   return (int)foo4 + (int)bar4;
>>>> +; }
>>>> +;
>>>> +; int test5() {
>>>> +;   struct SS* bar5 = &S;
>>>> +;   struct SS* foo5 = &S;
>>>> +;   foo5 = 0;
>>>> +;   return (int)foo5 + (int)bar5;
>>>> +; }
>>>> +;--------------------------------------------------------------------
>>>> +
>>>> +; CHECK:  ![[FOO1:.*]] = !DILocalVariable(name: "foo1"
>>>> +; CHECK:  ![[BAR1:.*]] = !DILocalVariable(name: "bar1"
>>>> +; CHECK:  ![[FOO2:.*]] = !DILocalVariable(name: "foo2"
>>>> +; CHECK:  ![[BAR2:.*]] = !DILocalVariable(name: "bar2"
>>>> +; CHECK:  ![[FOO3:.*]] = !DILocalVariable(name: "bar3"
>>>> +; CHECK:  ![[BAR3:.*]] = !DILocalVariable(name: "foo3"
>>>> +; CHECK:  ![[FOO4:.*]] = !DILocalVariable(name: "foo4"
>>>> +; CHECK:  ![[BAR4:.*]] = !DILocalVariable(name: "bar4"
>>>> +; CHECK:  ![[FOO5:.*]] = !DILocalVariable(name: "bar5"
>>>> +; CHECK:  ![[BAR5:.*]] = !DILocalVariable(name: "foo5"
>>>> +
>>>> +
>>>> +source_filename = "sdag-dangling-dbgvalue.c"
>>>> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>>>> +target triple = "x86_64-apple-macosx10.4.0"
>>>> +
>>>> +%struct.SS = type { i32, i32 }
>>>> +
>>>> + at S = global %struct.SS { i32 23, i32 -17 }, align 4, !dbg !0
>>>> +
>>>> +; Verify that the def comes before the debug-use for foo1.
>>>> +; TODO: Currently dbg.value for bar1 is dropped(?), is that expected?
>>>> +define i32 @test1() local_unnamed_addr #0 !dbg !17 {
>>>> +; CHECK-LABEL: bb.0.entry1
>>>> +; CHECK-NEXT:    [[REG1:%[0-9]+]]:gr64 =
>>>> +; CHECK-NEXT:    DBG_VALUE debug-use [[REG1]], debug-use $noreg, ![[FOO1]], !DIExpression()
>>>> +entry1:
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !20, metadata !DIExpression()), !dbg !23
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* null, metadata !22, metadata !DIExpression()), !dbg !24
>>>> +  ret i32 ptrtoint (%struct.SS* @S to i32), !dbg !25
>>>> +}
>>>> +
>>>> +; Verify that the def comes before the debug-use for bar2.
>>>> +; TODO: Currently dbg.value for foo2 is dropped. Seems to be a bug. The
>>>> +;       SelectionDAGBuilder should support several dangling dbg.value for the
>>>> +;       same value.
>>>> +define i32 @test2() local_unnamed_addr #0 !dbg !26 {
>>>> +; CHECK-LABEL: bb.0.entry2
>>>> +; CHECK-NEXT:    [[REG2:%[0-9]+]]:gr64 =
>>>> +; CHECK-NEXT:    DBG_VALUE debug-use [[REG2]], debug-use $noreg, ![[BAR2]], !DIExpression()
>>>> +entry2:
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !28, metadata !DIExpression()), !dbg !30
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !29, metadata !DIExpression()), !dbg !31
>>>> +  ret i32 add (i32 ptrtoint (%struct.SS* @S to i32), i32 ptrtoint (%struct.SS* @S to i32)), !dbg !32
>>>> +}
>>>> +
>>>> +; Verify that the def comes before the debug-use for foo3.
>>>> +; TODO: Currently dbg.value for bar3 is dropped. Seems to be a bug. The
>>>> +;       SelectionDAGBuilder should support several dangling dbg.value for the
>>>> +;       same value.
>>>> +define i32 @test3() local_unnamed_addr #0 !dbg !33 {
>>>> +; CHECK-LABEL: bb.0.entry3
>>>> +; CHECK-NEXT:    [[REG3:%[0-9]+]]:gr64 =
>>>> +; CHECK-NEXT:    DBG_VALUE debug-use [[REG3]], debug-use $noreg, ![[FOO3]], !DIExpression()
>>>> +entry3:
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !36, metadata !DIExpression()), !dbg !38
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !35, metadata !DIExpression()), !dbg !37
>>>> +  ret i32 add (i32 ptrtoint (%struct.SS* @S to i32), i32 ptrtoint (%struct.SS* @S to i32)), !dbg !39
>>>> +}
>>>> +
>>>> +; Verify that the def comes before the debug-use for bar4.
>>>> +; TODO: Currently dbg.value for foo4 is dropped. It is set to null and not
>>>> +;       used. Just like in test1 it can be discussed if there should be a
>>>> +;       DBG_VALUE for foo4 here.
>>>> +define i32 @test4() local_unnamed_addr #0 !dbg !40 {
>>>> +; CHECK-LABEL: bb.0.entry4
>>>> +; CHECK-NEXT:    [[REG4:%[0-9]+]]:gr64 =
>>>> +; CHECK-NEXT:    DBG_VALUE debug-use [[REG4]], debug-use $noreg, ![[BAR4]], !DIExpression()
>>>> +entry4:
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !42, metadata !DIExpression()), !dbg !44
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !43, metadata !DIExpression()), !dbg !45
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* null, metadata !42, metadata !DIExpression()), !dbg !44
>>>> +  ret i32 ptrtoint (%struct.SS* @S to i32), !dbg !46
>>>> +}
>>>> +
>>>> +; Verify that we do not get a DBG_VALUE that maps foo5 to @S here.
>>>> +; TODO: At the moment we do not get any DBG_VALUE at all here. If
>>>> +;       SelectionDAGBuilder should support several dangling dbg.value for the
>>>> +;       same value it would be possible to at least get a DBG_VALUE for
>>>> +;       bar5.
>>>> +; TODO: foo5 is set to null, and it is not really used. Just like in test1 it
>>>> +;       can be discussed if there should be a DBG_VALUE for foo5 here.
>>>> +define i32 @test5() local_unnamed_addr #0 !dbg !47 {
>>>> +; CHECK-LABEL: bb.0.entry5:
>>>> +; CHECK-NOT:     DBG_VALUE
>>>> +; CHECK:         RET
>>>> +entry5:
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !49, metadata !DIExpression()), !dbg !51
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !50, metadata !DIExpression()), !dbg !52
>>>> +  call void @llvm.dbg.value(metadata %struct.SS* null, metadata !50, metadata !DIExpression()), !dbg !52
>>>> +  ret i32 ptrtoint (%struct.SS* @S to i32), !dbg !53
>>>> +}
>>>> +
>>>> +; Function Attrs: nounwind readnone speculatable
>>>> +declare void @llvm.dbg.value(metadata, metadata, metadata) #1
>>>> +
>>>> +attributes #0 = { nounwind readnone uwtable }
>>>> +attributes #1 = { nounwind readnone speculatable }
>>>> +
>>>> +!llvm.dbg.cu <http://llvm.dbg.cu/> = !{!2}
>>>> +!llvm.module.flags = !{!12, !13, !14, !15}
>>>> +!llvm.ident = !{!16}
>>>> +
>>>> +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
>>>> +!1 = distinct !DIGlobalVariable(name: "S", scope: !2, file: !3, line: 4, type: !8, isLocal: false, isDefinition: true)
>>>> +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 7.0.0 (trunk 327229) (llvm/trunk 327239)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !5, globals: !7)
>>>> +!3 = !DIFile(filename: "sdag-dangling-dbgvalue.c", directory: "/repo/uabbpet/llvm-master")
>>>> +!4 = !{}
>>>> +!5 = !{!6}
>>>> +!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
>>>> +!7 = !{!0}
>>>> +!8 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "SS", file: !3, line: 1, size: 64, elements: !9)
>>>> +!9 = !{!10, !11}
>>>> +!10 = !DIDerivedType(tag: DW_TAG_member, name: "a", scope: !8, file: !3, line: 2, baseType: !6, size: 32)
>>>> +!11 = !DIDerivedType(tag: DW_TAG_member, name: "b", scope: !8, file: !3, line: 3, baseType: !6, size: 32, offset: 32)
>>>> +!12 = !{i32 2, !"Dwarf Version", i32 2}
>>>> +!13 = !{i32 2, !"Debug Info Version", i32 3}
>>>> +!14 = !{i32 1, !"wchar_size", i32 4}
>>>> +!15 = !{i32 7, !"PIC Level", i32 2}
>>>> +!16 = !{!"clang version 7.0.0 (trunk 327229) (llvm/trunk 327239)"}
>>>> +!17 = distinct !DISubprogram(name: "test1", scope: !3, file: !3, line: 6, type: !18, isLocal: false, isDefinition: true, scopeLine: 6, isOptimized: true, unit: !2, variables: !19)
>>>> +!18 = !DISubroutineType(types: !5)
>>>> +!19 = !{!20, !22}
>>>> +!20 = !DILocalVariable(name: "foo1", scope: !17, file: !3, line: 7, type: !21)
>>>> +!21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !8, size: 64)
>>>> +!22 = !DILocalVariable(name: "bar1", scope: !17, file: !3, line: 8, type: !21)
>>>> +!23 = !DILocation(line: 7, column: 14, scope: !17)
>>>> +!24 = !DILocation(line: 8, column: 14, scope: !17)
>>>> +!25 = !DILocation(line: 9, column: 3, scope: !17)
>>>> +!26 = distinct !DISubprogram(name: "test2", scope: !3, file: !3, line: 12, type: !18, isLocal: false, isDefinition: true, scopeLine: 12, isOptimized: true, unit: !2, variables: !27)
>>>> +!27 = !{!28, !29}
>>>> +!28 = !DILocalVariable(name: "foo2", scope: !26, file: !3, line: 13, type: !21)
>>>> +!29 = !DILocalVariable(name: "bar2", scope: !26, file: !3, line: 14, type: !21)
>>>> +!30 = !DILocation(line: 13, column: 14, scope: !26)
>>>> +!31 = !DILocation(line: 14, column: 14, scope: !26)
>>>> +!32 = !DILocation(line: 15, column: 3, scope: !26)
>>>> +!33 = distinct !DISubprogram(name: "test3", scope: !3, file: !3, line: 18, type: !18, isLocal: false, isDefinition: true, scopeLine: 18, isOptimized: true, unit: !2, variables: !34)
>>>> +!34 = !{!35, !36}
>>>> +!35 = !DILocalVariable(name: "bar3", scope: !33, file: !3, line: 19, type: !21)
>>>> +!36 = !DILocalVariable(name: "foo3", scope: !33, file: !3, line: 20, type: !21)
>>>> +!37 = !DILocation(line: 19, column: 14, scope: !33)
>>>> +!38 = !DILocation(line: 20, column: 14, scope: !33)
>>>> +!39 = !DILocation(line: 21, column: 3, scope: !33)
>>>> +!40 = distinct !DISubprogram(name: "test4", scope: !3, file: !3, line: 24, type: !18, isLocal: false, isDefinition: true, scopeLine: 24, isOptimized: true, unit: !2, variables: !41)
>>>> +!41 = !{!42, !43}
>>>> +!42 = !DILocalVariable(name: "foo4", scope: !40, file: !3, line: 25, type: !21)
>>>> +!43 = !DILocalVariable(name: "bar4", scope: !40, file: !3, line: 26, type: !21)
>>>> +!44 = !DILocation(line: 25, column: 14, scope: !40)
>>>> +!45 = !DILocation(line: 26, column: 14, scope: !40)
>>>> +!46 = !DILocation(line: 28, column: 3, scope: !40)
>>>> +!47 = distinct !DISubprogram(name: "test5", scope: !3, file: !3, line: 31, type: !18, isLocal: false, isDefinition: true, scopeLine: 31, isOptimized: true, unit: !2, variables: !48)
>>>> +!48 = !{!49, !50}
>>>> +!49 = !DILocalVariable(name: "bar5", scope: !47, file: !3, line: 32, type: !21)
>>>> +!50 = !DILocalVariable(name: "foo5", scope: !47, file: !3, line: 33, type: !21)
>>>> +!51 = !DILocation(line: 32, column: 14, scope: !47)
>>>> +!52 = !DILocation(line: 33, column: 14, scope: !47)
>>>> +!53 = !DILocation(line: 35, column: 3, scope: !47)
>>>> 
>>>> 
>>>> _______________________________________________
>>>> llvm-commits mailing list
>>>> llvm-commits at lists.llvm.org <mailto:llvm-commits at lists.llvm.org>
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits <http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits>
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20180329/690936c6/attachment.html>


More information about the llvm-commits mailing list