[llvm] r228764 - Debug Info: Support variables that are described by more than one MMI
Adrian Prantl
aprantl at apple.com
Tue Feb 10 15:45:35 PST 2015
> On Feb 10, 2015, at 3:33 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
> On Tue, Feb 10, 2015 at 3:18 PM, Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
> Author: adrian
> Date: Tue Feb 10 17:18:28 2015
> New Revision: 228764
>
> URL: http://llvm.org/viewvc/llvm-project?rev=228764&view=rev <http://llvm.org/viewvc/llvm-project?rev=228764&view=rev>
> Log:
> Debug Info: Support variables that are described by more than one MMI
> table entry. This happens when SROA splits up an alloca and the resulting
> allocas cannot be lowered to SSA values because their address is passed
> to a function.
>
> Forgot to git add the test case, perhaps? (& given the description, I hope the test case can be a bit cleaner/simpler than the reduced reproductions we were looking at earlier, but I realize that might not be the case)
Yes & yes (a bit). Thanks for noticing!
-- adrian
>
>
> Fixes PR22502.
>
> Modified:
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp?rev=228764&r1=228763&r2=228764&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp?rev=228764&r1=228763&r2=228764&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp Tue Feb 10 17:18:28 2015
> @@ -516,15 +516,21 @@ DwarfCompileUnit::constructVariableDIEIm
> }
>
> // .. else use frame index.
> - int FI = DV.getFrameIndex();
> - if (FI != ~0) {
> + if (DV.getFrameIndex().back() == ~0)
> + return VariableDie;
> +
> + auto Expr = DV.getExpression().begin();
> + DIELoc *Loc = new (DIEValueAllocator) DIELoc();
> + DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
> + for (auto FI : DV.getFrameIndex()) {
> unsigned FrameReg = 0;
> const TargetFrameLowering *TFI =
> Asm->TM.getSubtargetImpl()->getFrameLowering();
> int Offset = TFI->getFrameIndexReference(*Asm->MF, FI, FrameReg);
> - MachineLocation Location(FrameReg, Offset);
> - addVariableAddress(DV, *VariableDie, Location);
> + DwarfExpr.AddMachineRegIndirect(FrameReg, Offset);
> + DwarfExpr.AddExpression(*(Expr++));
> }
> + addBlock(*VariableDie, dwarf::DW_AT_location, Loc);
>
> return VariableDie;
> }
> @@ -767,7 +773,8 @@ void DwarfCompileUnit::addComplexAddress
> const MachineLocation &Location) {
> DIELoc *Loc = new (DIEValueAllocator) DIELoc();
> DIEDwarfExpression DwarfExpr(*Asm, *this, *Loc);
> - DIExpression Expr = DV.getExpression();
> + assert(DV.getExpression().size() == 1);
> + DIExpression Expr = DV.getExpression().back();
> bool ValidReg;
> if (Location.getOffset()) {
> ValidReg = DwarfExpr.AddMachineRegIndirect(Location.getReg(),
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=228764&r1=228763&r2=228764&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=228764&r1=228763&r2=228764&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Tue Feb 10 17:18:28 2015
> @@ -783,10 +783,9 @@ void DwarfDebug::collectVariableInfoFrom
> DIVariable DV(VI.Var);
> DIExpression Expr(VI.Expr);
> ensureAbstractVariableIsCreatedIfScoped(DV, Scope->getScopeNode());
> - ConcreteVariables.push_back(make_unique<DbgVariable>(DV, Expr, this));
> - DbgVariable *RegVar = ConcreteVariables.back().get();
> - RegVar->setFrameIndex(VI.Slot);
> - InfoHolder.addScopeVariable(Scope, RegVar);
> + auto RegVar = make_unique<DbgVariable>(DV, Expr, this, VI.Slot);
> + if (InfoHolder.addScopeVariable(Scope, RegVar.get()))
> + ConcreteVariables.push_back(std::move(RegVar));
> }
> }
>
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=228764&r1=228763&r2=228764&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=228764&r1=228763&r2=228764&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Tue Feb 10 17:18:28 2015
> @@ -67,41 +67,66 @@ public:
>
> //===----------------------------------------------------------------------===//
> /// \brief This class is used to track local variable information.
> +///
> +/// - Variables whose location changes over time have a DotDebugLocOffset and the
> +/// other fields are not used.
> +///
> +/// - Variables that are described by multiple MMI table entries have multiple
> +/// expressions and frame indices.
> class DbgVariable {
> - DIVariable Var; // Variable Descriptor.
> - DIExpression Expr; // Complex address location expression.
> - DIE *TheDIE; // Variable DIE.
> - unsigned DotDebugLocOffset; // Offset in DotDebugLocEntries.
> - const MachineInstr *MInsn; // DBG_VALUE instruction of the variable.
> - int FrameIndex;
> + DIVariable Var; /// Variable Descriptor.
> + SmallVector<DIExpression, 1> Expr; /// Complex address location expression.
> + DIE *TheDIE; /// Variable DIE.
> + unsigned DotDebugLocOffset; /// Offset in DotDebugLocEntries.
> + const MachineInstr *MInsn; /// DBG_VALUE instruction of the variable.
> + SmallVector<int, 1> FrameIndex; /// Frame index of the variable.
> DwarfDebug *DD;
>
> public:
> /// Construct a DbgVariable from a DIVariable.
> - DbgVariable(DIVariable V, DIExpression E, DwarfDebug *DD)
> - : Var(V), Expr(E), TheDIE(nullptr), DotDebugLocOffset(~0U),
> - MInsn(nullptr), FrameIndex(~0), DD(DD) {
> - assert(Var.Verify() && Expr.Verify());
> + DbgVariable(DIVariable V, DIExpression E, DwarfDebug *DD, int FI = ~0)
> + : Var(V), Expr(1, E), TheDIE(nullptr), DotDebugLocOffset(~0U),
> + MInsn(nullptr), DD(DD) {
> + FrameIndex.push_back(FI);
> + assert(Var.Verify() && E.Verify());
> }
>
> /// Construct a DbgVariable from a DEBUG_VALUE.
> /// AbstractVar may be NULL.
> DbgVariable(const MachineInstr *DbgValue, DwarfDebug *DD)
> - : Var(DbgValue->getDebugVariable()), Expr(DbgValue->getDebugExpression()),
> - TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(DbgValue),
> - FrameIndex(~0), DD(DD) {}
> + : Var(DbgValue->getDebugVariable()), Expr(1, DbgValue->getDebugExpression()),
> + TheDIE(nullptr), DotDebugLocOffset(~0U), MInsn(DbgValue), DD(DD) {
> + FrameIndex.push_back(~0);
> + }
>
> // Accessors.
> DIVariable getVariable() const { return Var; }
> - DIExpression getExpression() const { return Expr; }
> + const ArrayRef<DIExpression> getExpression() const { return Expr; }
> void setDIE(DIE &D) { TheDIE = &D; }
> DIE *getDIE() const { return TheDIE; }
> void setDotDebugLocOffset(unsigned O) { DotDebugLocOffset = O; }
> unsigned getDotDebugLocOffset() const { return DotDebugLocOffset; }
> StringRef getName() const { return Var.getName(); }
> const MachineInstr *getMInsn() const { return MInsn; }
> - int getFrameIndex() const { return FrameIndex; }
> - void setFrameIndex(int FI) { FrameIndex = FI; }
> + const ArrayRef<int> getFrameIndex() const { return FrameIndex; }
> +
> + void addMMIEntry(const DbgVariable &V) {
> + assert( DotDebugLocOffset == ~0U && !MInsn && "not an MMI entry");
> + assert(V.DotDebugLocOffset == ~0U && !V.MInsn && "not an MMI entry");
> + assert(V.Var == Var && "conflicting DIVariable");
> +
> + if (V.getFrameIndex().back() != ~0) {
> + auto E = V.getExpression();
> + auto FI = V.getFrameIndex();
> + Expr.append(E.begin(), E.end());
> + FrameIndex.append(FI.begin(), FI.end());
> + }
> + assert(Expr.size() > 1
> + ? std::all_of(Expr.begin(), Expr.end(),
> + [](DIExpression &E) { return E.isBitPiece(); })
> + : (true && "conflicting locations for variable"));
> + }
> +
> // Translate tag to proper Dwarf tag.
> dwarf::Tag getTag() const {
> if (Var.getTag() == dwarf::DW_TAG_arg_variable)
> @@ -128,14 +153,11 @@ public:
>
> bool variableHasComplexAddress() const {
> assert(Var.isVariable() && "Invalid complex DbgVariable!");
> - return Expr.getNumElements() > 0;
> + assert(Expr.size() == 1 &&
> + "variableHasComplexAddress() invoked on multi-FI variable");
> + return Expr.back().getNumElements() > 0;
> }
> bool isBlockByrefVariable() const;
> - unsigned getNumAddrElements() const {
> - assert(Var.isVariable() && "Invalid complex DbgVariable!");
> - return Expr.getNumElements();
> - }
> - uint64_t getAddrElement(unsigned i) const { return Expr.getElement(i); }
> DIType getType() const;
>
> private:
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp?rev=228764&r1=228763&r2=228764&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp?rev=228764&r1=228763&r2=228764&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.cpp Tue Feb 10 17:18:28 2015
> @@ -146,7 +146,7 @@ void DwarfFile::emitStrings(const MCSect
> StrPool.emit(*Asm, StrSection, OffsetSection);
> }
>
> -void DwarfFile::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
> +bool DwarfFile::addScopeVariable(LexicalScope *LS, DbgVariable *Var) {
> SmallVectorImpl<DbgVariable *> &Vars = ScopeVariables[LS];
> DIVariable DV = Var->getVariable();
> // Variables with positive arg numbers are parameters.
> @@ -168,13 +168,17 @@ void DwarfFile::addScopeVariable(Lexical
> // A later indexed parameter has been found, insert immediately before it.
> if (CurNum > ArgNum)
> break;
> - assert(CurNum != ArgNum && "Duplicate argument");
> + if (CurNum == ArgNum) {
> + (*I)->addMMIEntry(*Var);
> + return false;
> + }
> ++I;
> }
> Vars.insert(I, Var);
> - return;
> + return true;
> }
>
> Vars.push_back(Var);
> + return true;
> }
> }
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h?rev=228764&r1=228763&r2=228764&view=diff <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h?rev=228764&r1=228763&r2=228764&view=diff>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfFile.h Tue Feb 10 17:18:28 2015
> @@ -95,7 +95,8 @@ public:
> /// \brief Returns the string pool.
> DwarfStringPool &getStringPool() { return StrPool; }
>
> - void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
> + /// \returns false if the variable was merged with a previous one.
> + bool addScopeVariable(LexicalScope *LS, DbgVariable *Var);
>
> DenseMap<LexicalScope *, SmallVector<DbgVariable *, 8>> &getScopeVariables() {
> return ScopeVariables;
>
>
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