Author: Martin Braenne Date: 2023-07-10T06:45:53Z New Revision: e8a1560d1de9514d3f1631388fe966476778e540
URL: https://github.com/llvm/llvm-project/commit/e8a1560d1de9514d3f1631388fe966476778e540 DIFF: https://github.com/llvm/llvm-project/commit/e8a1560d1de9514d3f1631388fe966476778e540.diff LOG: [clang][dataflow] Various changes to handling of modeled fields. - Rename `getReferencedFields()` to `getModeledFields()`. Move the logic that returns all object fields when doing a context-sensitive analysis to here from `DataflowAnalysisContext::createStorageLocation()`. I think all callers of the previous `getReferencedFields()` should use this logic; the fact that they were not doing so looks like a bug. - Make `getModeledFields()` public. I have an upcoming patch that will need to use this function from Transfer.cpp, and there doesn't seem to be any reason why this function should not be public. - Use a `SmallSetVector` to get deterministic iteration order. I have a pending patch where I'm getting flaky tests because `Environment::createValueUnlessSelfReferential()` is non-deterministically populating different fields depending on the iteration order. This change fixes those flaky tests. Reviewed By: gribozavr2 Differential Revision: https://reviews.llvm.org/D154586 Added: Modified: clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp Removed: ################################################################################ diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h index 2a31a3477e8ceb..e5c325b876bd7a 100644 --- a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h +++ b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h @@ -51,8 +51,12 @@ class Logger; const Expr &ignoreCFGOmittedNodes(const Expr &E); const Stmt &ignoreCFGOmittedNodes(const Stmt &S); +/// A set of `FieldDecl *`. Use `SmallSetVector` to guarantee deterministic +/// iteration order. +using FieldSet = llvm::SmallSetVector<const FieldDecl *, 4>; + /// Returns the set of all fields in the type. -llvm::DenseSet<const FieldDecl *> getObjectFields(QualType Type); +FieldSet getObjectFields(QualType Type); struct ContextSensitiveOptions { /// The maximum depth to analyze. A value of zero is equivalent to disabling @@ -181,6 +185,10 @@ class DataflowAnalysisContext { /// been stored in flow conditions. Solver::Result querySolver(llvm::SetVector<const Formula *> Constraints); + /// Returns the fields of `Type`, limited to the set of fields modeled by this + /// context. + FieldSet getModeledFields(QualType Type); + private: friend class Environment; @@ -196,11 +204,7 @@ class DataflowAnalysisContext { }; // Extends the set of modeled field declarations. - void addModeledFields(const llvm::DenseSet<const FieldDecl *> &Fields); - - /// Returns the fields of `Type`, limited to the set of fields modeled by this - /// context. - llvm::DenseSet<const FieldDecl *> getReferencedFields(QualType Type); + void addModeledFields(const FieldSet &Fields); /// Adds all constraints of the flow condition identified by `Token` and all /// of its transitive dependencies to `Constraints`. `VisitedTokens` is used @@ -257,7 +261,7 @@ class DataflowAnalysisContext { llvm::DenseMap<const FunctionDecl *, ControlFlowContext> FunctionContexts; // Fields modeled by environments covered by this context. - llvm::DenseSet<const FieldDecl *> ModeledFields; + FieldSet ModeledFields; std::unique_ptr<Logger> LogOwner; // If created via flags. }; diff --git a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp index a807ef8209be85..b0c1014e3c975e 100644 --- a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp +++ b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp @@ -40,31 +40,28 @@ static llvm::cl::opt<std::string> DataflowLog( namespace clang { namespace dataflow { -void DataflowAnalysisContext::addModeledFields( - const llvm::DenseSet<const FieldDecl *> &Fields) { - llvm::set_union(ModeledFields, Fields); +FieldSet DataflowAnalysisContext::getModeledFields(QualType Type) { + // During context-sensitive analysis, a struct may be allocated in one + // function, but its field accessed in a function lower in the stack than + // the allocation. Since we only collect fields used in the function where + // the allocation occurs, we can't apply that filter when performing + // context-sensitive analysis. But, this only applies to storage locations, + // since field access it not allowed to fail. In contrast, field *values* + // don't need this allowance, since the API allows for uninitialized fields. + if (Opts.ContextSensitiveOpts) + return getObjectFields(Type); + + return llvm::set_intersection(getObjectFields(Type), ModeledFields); } -llvm::DenseSet<const FieldDecl *> -DataflowAnalysisContext::getReferencedFields(QualType Type) { - llvm::DenseSet<const FieldDecl *> Fields = getObjectFields(Type); - llvm::set_intersect(Fields, ModeledFields); - return Fields; +void DataflowAnalysisContext::addModeledFields(const FieldSet &Fields) { + ModeledFields.set_union(Fields); } StorageLocation &DataflowAnalysisContext::createStorageLocation(QualType Type) { if (!Type.isNull() && Type->isRecordType()) { llvm::DenseMap<const ValueDecl *, StorageLocation *> FieldLocs; - // During context-sensitive analysis, a struct may be allocated in one - // function, but its field accessed in a function lower in the stack than - // the allocation. Since we only collect fields used in the function where - // the allocation occurs, we can't apply that filter when performing - // context-sensitive analysis. But, this only applies to storage locations, - // since field access it not allowed to fail. In contrast, field *values* - // don't need this allowance, since the API allows for uninitialized fields. - auto Fields = Opts.ContextSensitiveOpts ? getObjectFields(Type) - : getReferencedFields(Type); - for (const FieldDecl *Field : Fields) + for (const FieldDecl *Field : getModeledFields(Type)) FieldLocs.insert({Field, &createStorageLocation(Field->getType())}); return arena().create<AggregateStorageLocation>(Type, std::move(FieldLocs)); } @@ -305,9 +302,8 @@ const Stmt &clang::dataflow::ignoreCFGOmittedNodes(const Stmt &S) { // FIXME: Does not precisely handle non-virtual diamond inheritance. A single // field decl will be modeled for all instances of the inherited field. -static void -getFieldsFromClassHierarchy(QualType Type, - llvm::DenseSet<const FieldDecl *> &Fields) { +static void getFieldsFromClassHierarchy(QualType Type, + clang::dataflow::FieldSet &Fields) { if (Type->isIncompleteType() || Type->isDependentType() || !Type->isRecordType()) return; @@ -320,9 +316,8 @@ getFieldsFromClassHierarchy(QualType Type, } /// Gets the set of all fields in the type. -llvm::DenseSet<const FieldDecl *> -clang::dataflow::getObjectFields(QualType Type) { - llvm::DenseSet<const FieldDecl *> Fields; +clang::dataflow::FieldSet clang::dataflow::getObjectFields(QualType Type) { + FieldSet Fields; getFieldsFromClassHierarchy(Type, Fields); return Fields; } diff --git a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp index 11bb7da97d52f4..c3de50894c9ede 100644 --- a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp +++ b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp @@ -170,8 +170,7 @@ static void insertIfFunction(const Decl &D, } static void -getFieldsGlobalsAndFuncs(const Decl &D, - llvm::DenseSet<const FieldDecl *> &Fields, +getFieldsGlobalsAndFuncs(const Decl &D, FieldSet &Fields, llvm::DenseSet<const VarDecl *> &Vars, llvm::DenseSet<const FunctionDecl *> &Funcs) { insertIfGlobal(D, Vars); @@ -188,8 +187,7 @@ getFieldsGlobalsAndFuncs(const Decl &D, /// global variables and functions that are declared in or referenced from /// sub-statements. static void -getFieldsGlobalsAndFuncs(const Stmt &S, - llvm::DenseSet<const FieldDecl *> &Fields, +getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields, llvm::DenseSet<const VarDecl *> &Vars, llvm::DenseSet<const FunctionDecl *> &Funcs) { for (auto *Child : S.children()) @@ -222,7 +220,7 @@ getFieldsGlobalsAndFuncs(const Stmt &S, void Environment::initFieldsGlobalsAndFuncs(const FunctionDecl *FuncDecl) { assert(FuncDecl->getBody() != nullptr); - llvm::DenseSet<const FieldDecl *> Fields; + FieldSet Fields; llvm::DenseSet<const VarDecl *> Vars; llvm::DenseSet<const FunctionDecl *> Funcs; @@ -708,7 +706,7 @@ void Environment::setValue(const StorageLocation &Loc, Value &Val) { const QualType Type = AggregateLoc.getType(); assert(Type->isRecordType()); - for (const FieldDecl *Field : DACtx->getReferencedFields(Type)) { + for (const FieldDecl *Field : DACtx->getModeledFields(Type)) { assert(Field != nullptr); StorageLocation &FieldLoc = AggregateLoc.getChild(*Field); MemberLocToStruct[&FieldLoc] = std::make_pair(StructVal, Field); @@ -846,7 +844,7 @@ Value *Environment::createValueUnlessSelfReferential( if (Type->isRecordType()) { CreatedValuesCount++; llvm::DenseMap<const ValueDecl *, Value *> FieldValues; - for (const FieldDecl *Field : DACtx->getReferencedFields(Type)) { + for (const FieldDecl *Field : DACtx->getModeledFields(Type)) { assert(Field != nullptr); QualType FieldType = Field->getType(); _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
