[clang] [Clang] Optimize -Wunsafe-buffer-usage. (PR #125492)

[Ilya Biryukov via cfe-commits]

================
@@ -186,106 +214,212 @@ class MatchDescendantVisitor : public DynamicRecursiveASTVisitor {
     return DynamicRecursiveASTVisitor::TraverseStmt(Node);
   }
 
+  void setASTContext(ASTContext &Context) { ActiveASTContext = &Context; }
+
+  void setHandler(const UnsafeBufferUsageHandler &NewHandler) {
+    Handler = &NewHandler;
+  }
+
 private:
   // Sets 'Matched' to true if 'Matcher' matches 'Node'
   //
   // Returns 'true' if traversal should continue after this function
   // returns, i.e. if no match is found or 'Bind' is 'BK_All'.
   template <typename T> bool match(const T &Node) {
-    internal::BoundNodesTreeBuilder RecursiveBuilder(*Builder);
-
-    if (Matcher->matches(DynTypedNode::create(Node), Finder,
-                         &RecursiveBuilder)) {
-      ResultBindings.addMatch(RecursiveBuilder);
+    if (Matcher->matches(DynTypedNode::create(Node), *ActiveASTContext,
+                         *Handler)) {
       Matches = true;
-      if (Bind != internal::ASTMatchFinder::BK_All)
+      if (!FindAll)
         return false; // Abort as soon as a match is found.
     }
     return true;
   }
 
-  const internal::DynTypedMatcher *const Matcher;
-  internal::ASTMatchFinder *const Finder;
-  internal::BoundNodesTreeBuilder *const Builder;
-  internal::BoundNodesTreeBuilder ResultBindings;
-  const internal::ASTMatchFinder::BindKind Bind;
+  FastMatcher *const Matcher;
+  // When true, finds all matches. When false, finds the first match and stops.
+  const bool FindAll;
   bool Matches;
   bool ignoreUnevaluatedContext;
+  ASTContext *ActiveASTContext;
+  const UnsafeBufferUsageHandler *Handler;
 };
 
 // Because we're dealing with raw pointers, let's define what we mean by that.
-static auto hasPointerType() {
-  return hasType(hasCanonicalType(pointerType()));
+static bool hasPointerType(const Expr &E) {
+  return isa<PointerType>(E.getType().getCanonicalType());
 }
 
-static auto hasArrayType() { return hasType(hasCanonicalType(arrayType())); }
-
-AST_MATCHER_P(Stmt, forEachDescendantEvaluatedStmt, internal::Matcher<Stmt>,
-              innerMatcher) {
-  const DynTypedMatcher &DTM = static_cast<DynTypedMatcher>(innerMatcher);
-
-  MatchDescendantVisitor Visitor(&DTM, Finder, Builder, ASTMatchFinder::BK_All,
-                                 true);
-  return Visitor.findMatch(DynTypedNode::create(Node));
+static bool hasArrayType(const Expr &E) {
+  return isa<ArrayType>(E.getType().getCanonicalType());
 }
 
-AST_MATCHER_P(Stmt, forEachDescendantStmt, internal::Matcher<Stmt>,
-              innerMatcher) {
-  const DynTypedMatcher &DTM = static_cast<DynTypedMatcher>(innerMatcher);
+static void
+forEachDescendantEvaluatedStmt(const Stmt *S, ASTContext &Ctx,
+                               const UnsafeBufferUsageHandler &Handler,
+                               FastMatcher &Matcher) {
+  MatchDescendantVisitor Visitor(Matcher, /* FindAll */ true,
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ilya-biryukov wrote:

NIT: LLVM tends to specify parameter names in the following style: `/*FindAll=*/` (at least the parts I've touched).
Could you update the code to follow the same style?

https://github.com/llvm/llvm-project/pull/125492