[clang] [alpha.webkit.UncountedCallArgsChecker] Skip std::forward in tryToFindPtrOrigin. (PR #111222)

[Ryosuke Niwa via cfe-commits]

https://github.com/rniwa created https://github.com/llvm/llvm-project/pull/111222

Ignore std::forward when it appears while looking for the pointer origin.

>From a67655fa83adab03351aa02d0982dd6a20726939 Mon Sep 17 00:00:00 2001
From: Ryosuke Niwa <rniwa at webkit.org>
Date: Fri, 4 Oct 2024 17:44:11 -0700
Subject: [PATCH] [alpha.webkit.UncountedCallArgsChecker] Skip std::forward in
 tryToFindPtrOrigin.

Ignore std::forward when it appears while looking for the pointer origin.
---
 .../StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp   |  5 +++++
 .../Checkers/WebKit/uncounted-obj-arg.cpp         | 15 +++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
index 394cb26f03cf99..b7b2f8a16f07b3 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/ASTUtils.cpp
@@ -101,6 +101,11 @@ bool tryToFindPtrOrigin(
         if (isSingleton(callee))
           return callback(E, true);
 
+        if (callee->isInStdNamespace() && safeGetName(callee) == "forward") {
+          E = call->getArg(0);
+          continue;
+        }
+
         if (isPtrConversion(callee)) {
           E = call->getArg(0);
           continue;
diff --git a/clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp b/clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp
index 97efb354f0371d..b6ab369f69a87d 100644
--- a/clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp
+++ b/clang/test/Analysis/Checkers/WebKit/uncounted-obj-arg.cpp
@@ -588,6 +588,8 @@ class UnrelatedClass {
     getFieldTrivial().nonTrivial23();
     // expected-warning at -1{{Call argument for 'this' parameter is uncounted and unsafe}}
   }
+
+  void setField(RefCounted*);
 };
 
 class UnrelatedClass2 {
@@ -598,11 +600,24 @@ class UnrelatedClass2 {
   RefCounted &getFieldTrivialRecursively() { return getFieldTrivial().getFieldTrivial(); }
   RefCounted *getFieldTrivialTernary() { return Field ? Field->getFieldTernary() : nullptr; }
 
+  template<typename T, typename ... AdditionalArgs>
+  void callSetField(T&& item, AdditionalArgs&&... args)
+  {
+    item.setField(std::forward<AdditionalArgs>(args)...);
+  }
+
+  template<typename T, typename ... AdditionalArgs>
+  void callSetField2(T&& item, AdditionalArgs&&... args)
+  {
+    item.setField(std::move<AdditionalArgs>(args)...);
+  }
+
   void test() {
     getFieldTrivialRecursively().trivial1(); // no-warning
     getFieldTrivialTernary()->trivial2(); // no-warning
     getFieldTrivialRecursively().someFunction();
     // expected-warning at -1{{Call argument for 'this' parameter is uncounted and unsafe}}
+    callSetField(getFieldTrivial(), refCountedObj()); // no-warning
   }
 };