[clang][dataflow] Expose getReferencedDecls and relocate free functions. (#88754)

Moves free functions from DataflowEnvironment.h/cc and
DataflowAnalysisContext.h/cc to RecordOps and a new ASTOps and exposes
them as needed for current use and to expose getReferencedDecls for
out-of-tree use.

Minimal change in functionality, only to modify the return type of
getReferenceDecls to return the collected decls instead of using output
params.

Tested with `ninja check-clang-tooling`.

Author: bazuzi

clang/docs/tools/clang-formatted-files.txt

@@ -123,6 +123,7 @@ clang/include/clang/Analysis/Analyses/CalledOnceCheck.h
 clang/include/clang/Analysis/Analyses/CFGReachabilityAnalysis.h
 clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
 clang/include/clang/Analysis/FlowSensitive/AdornedCFG.h
+clang/include/clang/Analysis/FlowSensitive/ASTOps.h
 clang/include/clang/Analysis/FlowSensitive/DataflowAnalysis.h
 clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
 clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
@@ -307,6 +308,7 @@ clang/lib/Analysis/CalledOnceCheck.cpp
 clang/lib/Analysis/CloneDetection.cpp
 clang/lib/Analysis/CodeInjector.cpp
 clang/lib/Analysis/FlowSensitive/AdornedCFG.cpp
+clang/lib/Analysis/FlowSensitive/ASTOps.cpp
 clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
 clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
 clang/lib/Analysis/FlowSensitive/DebugSupport.cpp

clang/include/clang/Analysis/FlowSensitive/ASTOps.h

@@ -0,0 +1,98 @@
+//===-- ASTOps.h -------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//  Operations on AST nodes that are used in flow-sensitive analysis.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_ASTOPS_H
+#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_ASTOPS_H
+
+#include "clang/AST/Decl.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/Type.h"
+#include "clang/Analysis/FlowSensitive/StorageLocation.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SetVector.h"
+
+namespace clang {
+namespace dataflow {
+
+/// Skip past nodes that the CFG does not emit. These nodes are invisible to
+/// flow-sensitive analysis, and should be ignored as they will effectively not
+/// exist.
+///
+///   * `ParenExpr` - The CFG takes the operator precedence into account, but
+///   otherwise omits the node afterwards.
+///
+///   * `ExprWithCleanups` - The CFG will generate the appropriate calls to
+///   destructors and then omit the node.
+///
+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.
+FieldSet getObjectFields(QualType Type);
+
+/// Returns whether `Fields` and `FieldLocs` contain the same fields.
+bool containsSameFields(const FieldSet &Fields,
+                        const RecordStorageLocation::FieldToLoc &FieldLocs);
+
+/// Helper class for initialization of a record with an `InitListExpr`.
+/// `InitListExpr::inits()` contains the initializers for both the base classes
+/// and the fields of the record; this helper class separates these out into two
+/// different lists. In addition, it deals with special cases associated with
+/// unions.
+class RecordInitListHelper {
+public:
+  // `InitList` must have record type.
+  RecordInitListHelper(const InitListExpr *InitList);
+
+  // Base classes with their associated initializer expressions.
+  ArrayRef<std::pair<const CXXBaseSpecifier *, Expr *>> base_inits() const {
+    return BaseInits;
+  }
+
+  // Fields with their associated initializer expressions.
+  ArrayRef<std::pair<const FieldDecl *, Expr *>> field_inits() const {
+    return FieldInits;
+  }
+
+private:
+  SmallVector<std::pair<const CXXBaseSpecifier *, Expr *>> BaseInits;
+  SmallVector<std::pair<const FieldDecl *, Expr *>> FieldInits;
+
+  // We potentially synthesize an `ImplicitValueInitExpr` for unions. It's a
+  // member variable because we store a pointer to it in `FieldInits`.
+  std::optional<ImplicitValueInitExpr> ImplicitValueInitForUnion;
+};
+
+/// A collection of several types of declarations, all referenced from the same
+/// function.
+struct ReferencedDecls {
+  /// Non-static member variables.
+  FieldSet Fields;
+  /// All variables with static storage duration, notably including static
+  /// member variables and static variables declared within a function.
+  llvm::DenseSet<const VarDecl *> Globals;
+  /// Free functions and member functions which are referenced (but not
+  /// necessarily called).
+  llvm::DenseSet<const FunctionDecl *> Functions;
+};
+
+/// Returns declarations that are declared in or referenced from `FD`.
+ReferencedDecls getReferencedDecls(const FunctionDecl &FD);
+
+} // namespace dataflow
+} // namespace clang
+
+#endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_ASTOPS_H

clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h

@@ -18,6 +18,7 @@
 #include "clang/AST/Decl.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/TypeOrdering.h"
+#include "clang/Analysis/FlowSensitive/ASTOps.h"
 #include "clang/Analysis/FlowSensitive/AdornedCFG.h"
 #include "clang/Analysis/FlowSensitive/Arena.h"
 #include "clang/Analysis/FlowSensitive/Solver.h"
@@ -30,38 +31,11 @@
 #include <cassert>
 #include <memory>
 #include <optional>
-#include <type_traits>
-#include <utility>
-#include <vector>
 
 namespace clang {
 namespace dataflow {
 class Logger;
 
-/// Skip past nodes that the CFG does not emit. These nodes are invisible to
-/// flow-sensitive analysis, and should be ignored as they will effectively not
-/// exist.
-///
-///   * `ParenExpr` - The CFG takes the operator precedence into account, but
-///   otherwise omits the node afterwards.
-///
-///   * `ExprWithCleanups` - The CFG will generate the appropriate calls to
-///   destructors and then omit the node.
-///
-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.
-FieldSet getObjectFields(QualType Type);
-
-/// Returns whether `Fields` and `FieldLocs` contain the same fields.
-bool containsSameFields(const FieldSet &Fields,
-                        const RecordStorageLocation::FieldToLoc &FieldLocs);
-
 struct ContextSensitiveOptions {
   /// The maximum depth to analyze. A value of zero is equivalent to disabling
   /// context-sensitive analysis entirely.

clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h

@@ -775,42 +775,6 @@ RecordStorageLocation *getImplicitObjectLocation(const CXXMemberCallExpr &MCE,
 RecordStorageLocation *getBaseObjectLocation(const MemberExpr &ME,
                                              const Environment &Env);
 
-/// Returns the fields of a `RecordDecl` that are initialized by an
-/// `InitListExpr`, in the order in which they appear in
-/// `InitListExpr::inits()`.
-/// `Init->getType()` must be a record type.
-std::vector<const FieldDecl *>
-getFieldsForInitListExpr(const InitListExpr *InitList);
-
-/// Helper class for initialization of a record with an `InitListExpr`.
-/// `InitListExpr::inits()` contains the initializers for both the base classes
-/// and the fields of the record; this helper class separates these out into two
-/// different lists. In addition, it deals with special cases associated with
-/// unions.
-class RecordInitListHelper {
-public:
-  // `InitList` must have record type.
-  RecordInitListHelper(const InitListExpr *InitList);
-
-  // Base classes with their associated initializer expressions.
-  ArrayRef<std::pair<const CXXBaseSpecifier *, Expr *>> base_inits() const {
-    return BaseInits;
-  }
-
-  // Fields with their associated initializer expressions.
-  ArrayRef<std::pair<const FieldDecl *, Expr *>> field_inits() const {
-    return FieldInits;
-  }
-
-private:
-  SmallVector<std::pair<const CXXBaseSpecifier *, Expr *>> BaseInits;
-  SmallVector<std::pair<const FieldDecl *, Expr *>> FieldInits;
-
-  // We potentially synthesize an `ImplicitValueInitExpr` for unions. It's a
-  // member variable because we store a pointer to it in `FieldInits`.
-  std::optional<ImplicitValueInitExpr> ImplicitValueInitForUnion;
-};
-
 /// Associates a new `RecordValue` with `Loc` and returns the new value.
 RecordValue &refreshRecordValue(RecordStorageLocation &Loc, Environment &Env);