[clang] Respect the [[clang::unsafe_buffer_usage]] attribute for field and constructor initializers (PR #91991)

[Dana Jansens via cfe-commits]

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@@ -3328,3 +3300,63 @@ void clang::checkUnsafeBufferUsage(const Decl *D,
     }
   }
 }
+
+void clang::checkUnsafeBufferUsage(const Decl *D,
+                                   UnsafeBufferUsageHandler &Handler,
+                                   bool EmitSuggestions) {
+#ifndef NDEBUG
+  Handler.clearDebugNotes();
+#endif
+
+  assert(D);
+
+  SmallVector<Stmt *> Stmts;
+
+  // We do not want to visit a Lambda expression defined inside a method
+  // independently. Instead, it should be visited along with the outer method.
+  // FIXME: do we want to do the same thing for `BlockDecl`s?
+  if (const auto *fd = dyn_cast<CXXMethodDecl>(D)) {
+    if (fd->getParent()->isLambda() && fd->getParent()->isLocalClass())
+      return;
+  }
+
+  // Do not emit fixit suggestions for functions declared in an
+  // extern "C" block.
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    for (FunctionDecl *FReDecl : FD->redecls()) {
+      if (FReDecl->isExternC()) {
+        EmitSuggestions = false;
+        break;
+      }
+    }
+
+    Stmts.push_back(FD->getBody());
+
+    if (const auto *ID = dyn_cast<CXXConstructorDecl>(D)) {
+      for (const CXXCtorInitializer *CI : ID->inits()) {
+        Stmts.push_back(CI->getInit());
+      }
+    }
+  }
+
+  if (const auto *FD = dyn_cast<FieldDecl>(D)) {
+    // Visit in-class initializers for fields.
+    if (!FD->hasInClassInitializer())
+      return;
+
+    Stmts.push_back(FD->getInClassInitializer());
+  }
+
+  if (isa<BlockDecl>(D) || isa<ObjCMethodDecl>(D)) {
+    Stmts.push_back(D->getBody());
+  }
+
+  assert(!Stmts.empty());
+
+  for (Stmt *S : Stmts) {
+    auto [FixableGadgets, WarningGadgets, Tracker] =
+        findGadgets(S, D->getASTContext(), Handler, EmitSuggestions);
+    applyGadgets(D, std::move(FixableGadgets), std::move(WarningGadgets),
----------------
danakj wrote:

If I understand correctly, we'd still collect a list of gadgets+trackers in the same way, but we'd pass them all at once to applyGadgets() so it could do some kind of global analysis over the full set if it wanted to. Though it will just need to iterate over them for now?

https://github.com/llvm/llvm-project/pull/91991