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Merge pull request #77951 from rastogishubham/LostVarsFalse
Add false positive detection to sil lost variables
This commit is contained in:
Shubham Sandeep Rastogi
GitHub
@@ -276,6 +276,11 @@ llvm::cl::opt<std::string> StatsOnlyFunctionsNamePattern(
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struct FunctionStat {
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int BlockCount = 0;
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int InstCount = 0;
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/// True when the FunctionStat is created for a SIL Function after a SIL
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/// Optimization pass has been run on it. When it is a post optimization SIL
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/// Function, we do not want to store anything in the InlinedAts Map in
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/// InstCountVisitor.
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bool NewFunc = false;
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/// Instruction counts per SILInstruction kind.
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InstructionCounts InstCounts;
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@@ -283,8 +288,10 @@ struct FunctionStat {
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unsigned, unsigned>;
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llvm::StringSet<> VarNames;
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llvm::DenseSet<FunctionStat::VarID> DebugVariables;
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llvm::DenseSet<const SILDebugScope *> VisitedScope;
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llvm::DenseMap<VarID, const SILDebugScope *> InlinedAts;
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FunctionStat(SILFunction *F);
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FunctionStat(SILFunction *F, bool NewFunc = false);
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FunctionStat() {}
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// The DebugVariables set contains pointers to VarNames. Disallow copy.
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@@ -384,15 +391,24 @@ struct ModuleStat {
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struct InstCountVisitor : SILInstructionVisitor<InstCountVisitor> {
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int BlockCount = 0;
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int InstCount = 0;
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/// True when the InstCountVisitor is created for a SIL Function after a SIL
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/// Optimization pass has been run on it. When it is a post optimization SIL
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/// Function, we do not want to store anything in the InlinedAts Map in
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/// InstCountVisitor.
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const bool &NewFunc;
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InstructionCounts &InstCounts;
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llvm::StringSet<> &VarNames;
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llvm::DenseSet<FunctionStat::VarID> &DebugVariables;
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llvm::DenseMap<FunctionStat::VarID, const SILDebugScope *> &InlinedAts;
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InstCountVisitor(InstructionCounts &InstCounts,
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llvm::StringSet<> &VarNames,
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llvm::DenseSet<FunctionStat::VarID> &DebugVariables)
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: InstCounts(InstCounts), VarNames(VarNames), DebugVariables(DebugVariables) {}
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InstCountVisitor(
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InstructionCounts &InstCounts, llvm::StringSet<> &VarNames,
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llvm::DenseSet<FunctionStat::VarID> &DebugVariables,
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llvm::DenseMap<FunctionStat::VarID, const SILDebugScope *> &InlinedAts,
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bool &NewFunc)
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: NewFunc(NewFunc), InstCounts(InstCounts), VarNames(VarNames),
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DebugVariables(DebugVariables), InlinedAts(InlinedAts) {}
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int getBlockCount() const {
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return BlockCount;
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@@ -431,6 +447,8 @@ struct InstCountVisitor : SILInstructionVisitor<InstCountVisitor> {
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varInfo->Scope ? varInfo->Scope : inst->getDebugScope(),
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UniqueName, line, col);
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DebugVariables.insert(key);
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if (!NewFunc)
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InlinedAts.try_emplace(key, varInfo->Scope->InlinedCallSite);
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}
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};
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@@ -710,16 +728,85 @@ bool isFirstTimeData(int Old, int New) {
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return Old == 0 && New != Old;
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}
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int computeLostVariables(llvm::DenseSet<FunctionStat::VarID> &Old,
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llvm::DenseSet<FunctionStat::VarID> &New) {
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unsigned count = 0;
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for (auto &var : Old) {
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if (New.contains(var))
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continue;
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// llvm::dbgs() << "Lost variable: " << std::get<1>(var) << "\n";
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count++;
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/// Return true if \p Scope is the same as \p DbgValScope or a child scope of
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/// \p DbgValScope, return false otherwise.
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bool isScopeChildOfOrEqualTo(const SILDebugScope *Scope,
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const SILDebugScope *DbgValScope) {
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llvm::DenseSet<const SILDebugScope *> VisitedScope;
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while (Scope != nullptr) {
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if (VisitedScope.find(Scope) == VisitedScope.end()) {
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VisitedScope.insert(Scope);
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if (Scope == DbgValScope) {
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return true;
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}
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if (auto *S = dyn_cast<const SILDebugScope *>(Scope->Parent))
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Scope = S;
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} else
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return false;
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}
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return count;
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return false;
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}
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/// Return true if \p InlinedAt is the same as \p DbgValInlinedAt or part of
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/// the InlinedAt chain, return false otherwise.
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bool isInlinedAtChildOfOrEqualTo(const SILDebugScope *InlinedAt,
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const SILDebugScope *DbgValInlinedAt) {
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if (DbgValInlinedAt == InlinedAt)
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return true;
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if (!DbgValInlinedAt)
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return false;
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if (!InlinedAt)
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return false;
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auto *IA = InlinedAt;
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while (IA) {
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if (IA == DbgValInlinedAt)
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return true;
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IA = IA->InlinedCallSite;
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}
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return false;
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}
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int computeLostVariables(SILFunction *F, FunctionStat &Old, FunctionStat &New) {
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unsigned LostCount = 0;
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unsigned PrevLostCount = 0;
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auto &OldSet = Old.DebugVariables;
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auto &NewSet = New.DebugVariables;
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// Find an Instruction that shares the same scope as the dropped debug_value
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// or has a scope that is the child of the scope of the debug_value, and has
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// an inlinedAt equal to the inlinedAt of the debug_value or it's inlinedAt
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// chain contains the inlinedAt of the debug_value, if such an Instruction is
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// found, debug information is dropped.
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for (auto &Var : OldSet) {
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if (NewSet.contains(Var))
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continue;
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auto &DbgValScope = std::get<0>(Var);
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for (auto &BB : *F) {
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for (auto &I : BB) {
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if (I.isDebugInstruction()) {
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auto DbgLoc = I.getDebugLocation();
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auto Scope = DbgLoc.getScope();
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// If the Scope is a child of, or equal to the DbgValScope and is
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// inlined at the Var's InlinedAt location, return true to signify
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// that the Var has been dropped.
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if (isScopeChildOfOrEqualTo(Scope, DbgValScope)) {
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if (isInlinedAtChildOfOrEqualTo(Scope->InlinedCallSite,
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Old.InlinedAts[Var])) {
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// Found another instruction in the variable's scope, so there
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// exists a break point at which the variable could be observed.
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// Count it as dropped.
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LostCount++;
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break;
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}
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}
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}
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}
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if (PrevLostCount != LostCount) {
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PrevLostCount = LostCount;
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break;
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}
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}
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}
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return LostCount;
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}
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/// Dump statistics for a SILFunction. It is only used if a user asked to
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@@ -782,8 +869,7 @@ void processFuncStatsChanges(SILFunction *F, FunctionStat &OldStat,
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// Compute deltas.
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double DeltaBlockCount = computeDelta(OldStat.BlockCount, NewStat.BlockCount);
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double DeltaInstCount = computeDelta(OldStat.InstCount, NewStat.InstCount);
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int LostVariables = computeLostVariables(OldStat.DebugVariables,
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NewStat.DebugVariables);
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int LostVariables = computeLostVariables(F, OldStat, NewStat);
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NewLineInserter nl;
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@@ -959,7 +1045,7 @@ void OptimizerStatsAnalysis::updateModuleStats(TransformationContext &Ctx) {
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InvalidatedFuncs.pop_back();
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auto &FuncStat = getFunctionStat(F);
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auto &OldFuncStat = FuncStat;
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FunctionStat NewFuncStat(F);
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FunctionStat NewFuncStat(F, true);
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processFuncStatsChanges(F, OldFuncStat, NewFuncStat, Ctx);
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NewModStat.subFunctionStat(OldFuncStat);
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NewModStat.addFunctionStat(NewFuncStat);
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@@ -984,7 +1070,7 @@ void OptimizerStatsAnalysis::updateModuleStats(TransformationContext &Ctx) {
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AddedFuncs.pop_back();
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auto &FuncStat = getFunctionStat(F);
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FunctionStat OldFuncStat;
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FunctionStat NewFuncStat(F);
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FunctionStat NewFuncStat(F, true);
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processFuncStatsChanges(F, OldFuncStat, NewFuncStat, Ctx);
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NewModStat.addFunctionStat(NewFuncStat);
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FuncStat = std::move(NewFuncStat);
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@@ -1003,8 +1089,8 @@ void OptimizerStatsAnalysis::updateModuleStats(TransformationContext &Ctx) {
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ModStat = NewModStat;
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}
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FunctionStat::FunctionStat(SILFunction *F) {
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InstCountVisitor V(InstCounts, VarNames, DebugVariables);
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FunctionStat::FunctionStat(SILFunction *F, bool NewFunc) : NewFunc(NewFunc) {
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InstCountVisitor V(InstCounts, VarNames, DebugVariables, InlinedAts, NewFunc);
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V.visitSILFunction(F);
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BlockCount = V.getBlockCount();
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InstCount = V.getInstCount();
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97
test/DebugInfo/dropped-var.sil
Normal file
97
test/DebugInfo/dropped-var.sil
Normal file
@@ -0,0 +1,97 @@
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// RUN: %target-sil-opt --diagnose-unreachable -o - %s -sil-stats-lost-variables 2>&1 | %FileCheck %s
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// CHECK: function, lostvars, Pass List Pipeline, DiagnoseUnreachable, 1, 1, {{[0-9]+}}, $s4test3bar1yS2i_tF
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sil_stage raw
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import Builtin
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import Swift
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import SwiftShims
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sil_scope 1 { loc "file.swift":1:6 parent @$s4test3bar1yS2i_tF : $@convention(thin) (Int) -> Int }
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// main
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// Isolation: unspecified
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sil [ossa] @main : $@convention(c) (Int32, UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>) -> Int32 {
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bb0(%0 : $Int32, %1 : $UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>):
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%2 = integer_literal $Builtin.Int32, 0 // user: %3; auto_gen
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%3 = struct $Int32 (%2 : $Builtin.Int32) // user: %4; auto_gen
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return %3 : $Int32 // id: %4; auto_gen
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} // end sil function 'main'
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// bar(y:)
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// Isolation: unspecified
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sil hidden [ossa] @$s4test3bar1yS2i_tF : $@convention(thin) (Int) -> Int {
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// %0 "y" // users: %5, %1
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bb0(%0 : $Int):
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debug_value %0 : $Int, let, name "y", argno 1 // id: %1; line:1:10:in_prologue
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%2 = integer_literal $Builtin.Int1, 0 // user: %3; line:2:11:minlined
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cond_br %2, bb1, bb2 // id: %3; line:2:11
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bb1: // Preds: bb0
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%4 = integer_literal $Builtin.Int64, 1 // user: %7; line:3:20:minlined
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debug_value %4 : $Builtin.Int64, let, name "num"
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%5 = struct_extract %0 : $Int, #Int._value // user: %7; line:3:18:minlined
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%6 = integer_literal $Builtin.Int1, -1 // user: %7; line:3:18:minlined
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%7 = builtin "sadd_with_overflow_Int64"(%5 : $Builtin.Int64, %4 : $Builtin.Int64, %6 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1) // user: %8; line:3:18:minlined
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(%8, %9) = destructure_tuple %7 : $(Builtin.Int64, Builtin.Int1) // users: %11, %10; line:3:18:minlined
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cond_fail %9 : $Builtin.Int1, "arithmetic overflow" // id: %10; line:3:18:minlined
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%11 = struct $Int (%8 : $Builtin.Int64) // user: %12; line:3:18:minlined
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br bb3(%11 : $Int) // id: %12; line:3:9:return
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bb2: // Preds: bb0
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%13 = integer_literal $Builtin.Int64, 1 // user: %14; line:5:12:minlined
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%14 = struct $Int (%13 : $Builtin.Int64) // user: %15; line:5:12:minlined
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br bb3(%14 : $Int) // id: %15; line:5:5:return
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// %16 // user: %17
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bb3(%16 : $Int): // Preds: bb2 bb1
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return %16 : $Int // id: %17; line:6:1:cleanup
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// Do not count as dropped variable if there is no instruction that belongs to the same scope as lost debug_value
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bb4:
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%17 = integer_literal $Builtin.Int64, 1, loc "file.swift":1:6, scope 1
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debug_value %17 : $Builtin.Int64, let, name "num", loc "file.swift":1:6, scope 1
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%18 = struct $Int (%17 : $Builtin.Int64)
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br bb3(%18: $Int)
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} // end sil function '$s4test3bar1yS2i_tF'
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// Int.init(_builtinIntegerLiteral:)
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// Isolation: unspecified
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sil public_external [transparent] [serialized] [canonical] [ossa] @$sSi22_builtinIntegerLiteralSiBI_tcfC : $@convention(method) (Builtin.IntLiteral, @thin Int.Type) -> Int {
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// %0 // user: %2
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bb0(%0 : $Builtin.IntLiteral, %1 : $@thin Int.Type):
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%2 = builtin "s_to_s_checked_trunc_IntLiteral_Int64"(%0 : $Builtin.IntLiteral) : $(Builtin.Int64, Builtin.Int1) // user: %3; no_loc
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(%3, %4) = destructure_tuple %2 : $(Builtin.Int64, Builtin.Int1) // user: %5; no_loc
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%5 = struct $Int (%3 : $Builtin.Int64) // user: %6; no_loc
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return %5 : $Int // id: %6; no_loc
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} // end sil function '$sSi22_builtinIntegerLiteralSiBI_tcfC'
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// static Int.> infix(_:_:)
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// Isolation: unspecified
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sil public_external [transparent] [serialized] [canonical] [ossa] @$sSi1goiySbSi_SitFZ : $@convention(method) (Int, Int, @thin Int.Type) -> Bool {
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// %0 // user: %4
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// %1 // user: %3
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bb0(%0 : $Int, %1 : $Int, %2 : $@thin Int.Type):
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%3 = struct_extract %1 : $Int, #Int._value // user: %5; no_loc
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%4 = struct_extract %0 : $Int, #Int._value // user: %5; no_loc
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%5 = builtin "cmp_slt_Int64"(%3 : $Builtin.Int64, %4 : $Builtin.Int64) : $Builtin.Int1 // user: %6; no_loc
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%6 = struct $Bool (%5 : $Builtin.Int1) // user: %7; no_loc
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return %6 : $Bool // id: %7; no_loc
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} // end sil function '$sSi1goiySbSi_SitFZ'
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// static Int.+ infix(_:_:)
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// Isolation: unspecified
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sil public_external [transparent] [serialized] [canonical] [ossa] @$sSi1poiyS2i_SitFZ : $@convention(method) (Int, Int, @thin Int.Type) -> Int {
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// %0 // user: %3
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// %1 // user: %4
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bb0(%0 : $Int, %1 : $Int, %2 : $@thin Int.Type):
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%3 = struct_extract %0 : $Int, #Int._value // user: %6; no_loc
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%4 = struct_extract %1 : $Int, #Int._value // user: %6; no_loc
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%5 = integer_literal $Builtin.Int1, -1 // user: %6; no_loc
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%6 = builtin "sadd_with_overflow_Int64"(%3 : $Builtin.Int64, %4 : $Builtin.Int64, %5 : $Builtin.Int1) : $(Builtin.Int64, Builtin.Int1) // user: %7; no_loc
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(%7, %8) = destructure_tuple %6 : $(Builtin.Int64, Builtin.Int1) // users: %10, %9; no_loc
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cond_fail %8 : $Builtin.Int1, "arithmetic overflow" // id: %9; no_loc
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%10 = struct $Int (%7 : $Builtin.Int64) // user: %11; no_loc
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return %10 : $Int // id: %11; no_loc
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} // end sil function '$sSi1poiyS2i_SitFZ'
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