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

[via cfe-commits]

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@@ -0,0 +1,214 @@
+//===-- 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.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/FlowSensitive/ASTOps.h"
+#include "clang/AST/ComputeDependence.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclBase.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/Stmt.h"
+#include "clang/AST/Type.h"
+#include "clang/Analysis/FlowSensitive/StorageLocation.h"
+#include "clang/Basic/LLVM.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/STLExtras.h"
+#include <cassert>
+#include <iterator>
+#include <vector>
+
+#define DEBUG_TYPE "dataflow"
+
+namespace clang::dataflow {
+std::vector<const FieldDecl *>
+getFieldsForInitListExpr(const InitListExpr *InitList) {
+  const RecordDecl *RD = InitList->getType()->getAsRecordDecl();
+  assert(RD != nullptr);
+
+  std::vector<const FieldDecl *> Fields;
+
+  if (InitList->getType()->isUnionType()) {
+    Fields.push_back(InitList->getInitializedFieldInUnion());
+    return Fields;
+  }
+
+  // Unnamed bitfields are only used for padding and do not appear in
+  // `InitListExpr`'s inits. However, those fields do appear in `RecordDecl`'s
+  // field list, and we thus need to remove them before mapping inits to
+  // fields to avoid mapping inits to the wrongs fields.
+  llvm::copy_if(
+      RD->fields(), std::back_inserter(Fields),
+      [](const FieldDecl *Field) { return !Field->isUnnamedBitfield(); });
+  return Fields;
+}
+
+static void insertIfGlobal(const Decl &D,
+                           llvm::DenseSet<const VarDecl *> &Vars) {
+  if (auto *V = dyn_cast<VarDecl>(&D))
+    if (V->hasGlobalStorage())
+      Vars.insert(V);
+}
+
+static void insertIfFunction(const Decl &D,
+                             llvm::DenseSet<const FunctionDecl *> &Funcs) {
+  if (auto *FD = dyn_cast<FunctionDecl>(&D))
+    Funcs.insert(FD);
+}
+
+static MemberExpr *getMemberForAccessor(const CXXMemberCallExpr &C) {
+  // Use getCalleeDecl instead of getMethodDecl in order to handle
+  // pointer-to-member calls.
+  const auto *MethodDecl = dyn_cast_or_null<CXXMethodDecl>(C.getCalleeDecl());
+  if (!MethodDecl)
+    return nullptr;
+  auto *Body = dyn_cast_or_null<CompoundStmt>(MethodDecl->getBody());
+  if (!Body || Body->size() != 1)
+    return nullptr;
+  if (auto *RS = dyn_cast<ReturnStmt>(*Body->body_begin()))
+    if (auto *Return = RS->getRetValue())
+      return dyn_cast<MemberExpr>(Return->IgnoreParenImpCasts());
+  return nullptr;
+}
+
+static void getReferencedDecls(const Decl &D, FieldSet &Fields,
+                               llvm::DenseSet<const VarDecl *> &Vars,
+                               llvm::DenseSet<const FunctionDecl *> &Funcs) {
+  insertIfGlobal(D, Vars);
+  insertIfFunction(D, Funcs);
+  if (const auto *Decomp = dyn_cast<DecompositionDecl>(&D))
+    for (const auto *B : Decomp->bindings())
+      if (auto *ME = dyn_cast_or_null<MemberExpr>(B->getBinding()))
+        // FIXME: should we be using `E->getFoundDecl()`?
+        if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
+          Fields.insert(FD);
+}
+
+/// Traverses `S` and inserts into `Fields`, `Vars` and `Funcs` any fields,
+/// global variables and functions that are declared in or referenced from
+/// sub-statements.
+static void getReferencedDecls(const Stmt &S, FieldSet &Fields,
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martinboehme wrote:

Again, suggest a `ReferencedDecls` parameter. This would also make the multiple recursive calls less verbose.

https://github.com/llvm/llvm-project/pull/88754