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

David Blaikie via llvm-commits llvm-commits at lists.llvm.org
Thu Mar 29 09:02:42 PDT 2018


Seeing about a 7.5% increase in (compressed) debug_loc (and 4.2% increase
in debug_info) in one binary at Google.

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).

On Mon, Mar 12, 2018 at 11:05 AM Bjorn Pettersson via llvm-commits <
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
> 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.
>
> 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
>
> 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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
>
> ==============================================================================
> --- 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 = !{!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)
>
>
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