[clang] [llvm] Introduce a new WebKit checker for a unchecked local variable (PR #113708)

Ryosuke Niwa via cfe-commits cfe-commits at lists.llvm.org
Thu Oct 31 22:43:40 PDT 2024


https://github.com/rniwa updated https://github.com/llvm/llvm-project/pull/113708

>From cf5ca301bc9ed2c65eed92e7299bf598d5f88103 Mon Sep 17 00:00:00 2001
From: Ryosuke Niwa <rniwa at webkit.org>
Date: Sat, 14 Sep 2024 01:46:23 -0700
Subject: [PATCH 1/2] Introduce a new WebKit checker for a unchecked local
 variable

This PR introduces alpha.webkit.UncheckedLocalVarsChecker which detects a raw reference or a raw pointer
local, static, or global variable to a CheckedPtr capable object without a guardian variable in an outer scope.
---
 clang/docs/analyzer/checkers.rst              |  47 ++-
 .../clang/StaticAnalyzer/Checkers/Checkers.td |   4 +
 .../StaticAnalyzer/Checkers/CMakeLists.txt    |   2 +-
 .../Checkers/WebKit/PtrTypesSemantics.cpp     |   9 +
 .../Checkers/WebKit/PtrTypesSemantics.h       |   4 +
 ...cker.cpp => RawPtrRefLocalVarsChecker.cpp} |  54 ++-
 .../Analysis/Checkers/WebKit/mock-types.h     |   2 +
 .../Checkers/WebKit/unchecked-local-vars.cpp  | 342 ++++++++++++++++++
 .../lib/StaticAnalyzer/Checkers/BUILD.gn      |   2 +-
 9 files changed, 449 insertions(+), 17 deletions(-)
 rename clang/lib/StaticAnalyzer/Checkers/WebKit/{UncountedLocalVarsChecker.cpp => RawPtrRefLocalVarsChecker.cpp} (85%)
 create mode 100644 clang/test/Analysis/Checkers/WebKit/unchecked-local-vars.cpp

diff --git a/clang/docs/analyzer/checkers.rst b/clang/docs/analyzer/checkers.rst
index 58dbd686a6dc9f..f56f603a8f6eab 100644
--- a/clang/docs/analyzer/checkers.rst
+++ b/clang/docs/analyzer/checkers.rst
@@ -3615,7 +3615,7 @@ These are examples of cases that we consider safe:
       RefCountable* uncounted = this; // ok
     }
 
-Here are some examples of situations that we warn about as they *might* be potentially unsafe. The logic is that either we're able to guarantee that an argument is safe or it's considered if not a bug then bug-prone.
+Here are some examples of situations that we warn about as they *might* be potentially unsafe. The logic is that either we're able to guarantee that a local variable is safe or it's considered unsafe.
 
   .. code-block:: cpp
 
@@ -3634,11 +3634,48 @@ Here are some examples of situations that we warn about as they *might* be poten
       RefCountable* uncounted = counted.get(); // warn
     }
 
-We don't warn about these cases - we don't consider them necessarily safe but since they are very common and usually safe we'd introduce a lot of false positives otherwise:
-- variable defined in condition part of an ```if``` statement
-- variable defined in init statement condition of a ```for``` statement
+alpha.webkit.UncheckedLocalVarsChecker
+""""""""""""""""""""""""""""""""""""""
+The goal of this rule is to make sure that any unchecked local variable is backed by a CheckedPtr or CheckedRef with lifetime that is strictly larger than the scope of the unchecked local variable. To be on the safe side we require the scope of an unchecked variable to be embedded in the scope of CheckedPtr/CheckRef object that backs it.
+
+These are examples of cases that we consider safe:
+
+  .. code-block:: cpp
 
-For the time being we also don't warn about uninitialized uncounted local variables.
+    void foo1() {
+      CheckedPtr<RefCountable> counted;
+      // The scope of uncounted is EMBEDDED in the scope of counted.
+      {
+        RefCountable* uncounted = counted.get(); // ok
+      }
+    }
+
+    void foo2(CheckedPtr<RefCountable> counted_param) {
+      RefCountable* uncounted = counted_param.get(); // ok
+    }
+
+    void FooClass::foo_method() {
+      RefCountable* uncounted = this; // ok
+    }
+
+Here are some examples of situations that we warn about as they *might* be potentially unsafe. The logic is that either we're able to guarantee that a local variable is safe or it's considered unsafe.
+
+  .. code-block:: cpp
+
+    void foo1() {
+      RefCountable* uncounted = new RefCountable; // warn
+    }
+
+    RefCountable* global_uncounted;
+    void foo2() {
+      RefCountable* uncounted = global_uncounted; // warn
+    }
+
+    void foo3() {
+      RefPtr<RefCountable> counted;
+      // The scope of uncounted is not EMBEDDED in the scope of counted.
+      RefCountable* uncounted = counted.get(); // warn
+    }
 
 Debug Checkers
 ---------------
diff --git a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
index 349040c15eeb83..2685d194482123 100644
--- a/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ b/clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -1782,4 +1782,8 @@ def UncountedLocalVarsChecker : Checker<"UncountedLocalVarsChecker">,
   HelpText<"Check uncounted local variables.">,
   Documentation<HasDocumentation>;
 
+def UncheckedLocalVarsChecker : Checker<"UncheckedLocalVarsChecker">,
+  HelpText<"Check unchecked local variables.">,
+  Documentation<HasDocumentation>;
+
 } // end alpha.webkit
diff --git a/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt b/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
index 6da3665ab9a4df..4f2806593aaa30 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
+++ b/clang/lib/StaticAnalyzer/Checkers/CMakeLists.txt
@@ -138,7 +138,7 @@ add_clang_library(clangStaticAnalyzerCheckers
   WebKit/RefCntblBaseVirtualDtorChecker.cpp
   WebKit/UncountedCallArgsChecker.cpp
   WebKit/UncountedLambdaCapturesChecker.cpp
-  WebKit/UncountedLocalVarsChecker.cpp
+  WebKit/RawPtrRefLocalVarsChecker.cpp
 
   LINK_LIBS
   clangAST
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
index 2293dcf1d4bd64..5d39d02a2f40f7 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
@@ -200,6 +200,15 @@ std::optional<bool> isUncountedPtr(const QualType T) {
   return false;
 }
 
+std::optional<bool> isUncheckedPtr(const QualType T)
+{
+  if (T->isPointerType() || T->isReferenceType()) {
+    if (auto *CXXRD = T->getPointeeCXXRecordDecl())
+      return isUnchecked(CXXRD);
+  }
+  return false;
+}
+
 std::optional<bool> isUnsafePtr(const QualType T) {
   if (T->isPointerType() || T->isReferenceType()) {
     if (auto *CXXRD = T->getPointeeCXXRecordDecl()) {
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
index 4b41ca96e1df1d..30bdaed706bb53 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.h
@@ -63,6 +63,10 @@ std::optional<bool> isUncounted(const clang::CXXRecordDecl* Class);
 /// class, false if not, std::nullopt if inconclusive.
 std::optional<bool> isUncountedPtr(const clang::QualType T);
 
+/// \returns true if \p T is either a raw pointer or reference to an unchecked
+/// class, false if not, std::nullopt if inconclusive.
+std::optional<bool> isUncheckedPtr(const clang::QualType T);
+
 /// \returns true if \p T is a RefPtr, Ref, CheckedPtr, CheckedRef, or its
 /// variant, false if not.
 bool isSafePtrType(const clang::QualType T);
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedLocalVarsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
similarity index 85%
rename from clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedLocalVarsChecker.cpp
rename to clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
index 5cdf047738abcb..0842cdbc4037b7 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedLocalVarsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
@@ -103,15 +103,18 @@ bool isGuardedScopeEmbeddedInGuardianScope(const VarDecl *Guarded,
   return false;
 }
 
-class UncountedLocalVarsChecker
+class RawPtrRefLocalVarsChecker
     : public Checker<check::ASTDecl<TranslationUnitDecl>> {
-  BugType Bug{this,
-              "Uncounted raw pointer or reference not provably backed by "
-              "ref-counted variable",
-              "WebKit coding guidelines"};
+  BugType Bug;
   mutable BugReporter *BR;
 
 public:
+  RawPtrRefLocalVarsChecker(const char* description)
+      : Bug(this, description, "WebKit coding guidelines") {}
+
+  virtual std::optional<bool> isUnsafePtr(const QualType T) const = 0;
+  virtual const char *ptrKind() const = 0;
+
   void checkASTDecl(const TranslationUnitDecl *TUD, AnalysisManager &MGR,
                     BugReporter &BRArg) const {
     BR = &BRArg;
@@ -120,14 +123,14 @@ class UncountedLocalVarsChecker
     // visit template instantiations or lambda classes. We
     // want to visit those, so we make our own RecursiveASTVisitor.
     struct LocalVisitor : public RecursiveASTVisitor<LocalVisitor> {
-      const UncountedLocalVarsChecker *Checker;
+      const RawPtrRefLocalVarsChecker *Checker;
       Decl *DeclWithIssue{nullptr};
 
       TrivialFunctionAnalysis TFA;
 
       using Base = RecursiveASTVisitor<LocalVisitor>;
 
-      explicit LocalVisitor(const UncountedLocalVarsChecker *Checker)
+      explicit LocalVisitor(const RawPtrRefLocalVarsChecker *Checker)
           : Checker(Checker) {
         assert(Checker);
       }
@@ -199,7 +202,7 @@ class UncountedLocalVarsChecker
     if (shouldSkipVarDecl(V))
       return;
 
-    std::optional<bool> IsUncountedPtr = isUncountedPtr(V->getType());
+    std::optional<bool> IsUncountedPtr = isUnsafePtr(V->getType());
     if (IsUncountedPtr && *IsUncountedPtr) {
       if (tryToFindPtrOrigin(
               Value, /*StopAtFirstRefCountedObj=*/false,
@@ -262,7 +265,7 @@ class UncountedLocalVarsChecker
     llvm::raw_svector_ostream Os(Buf);
 
     if (dyn_cast<ParmVarDecl>(V)) {
-      Os << "Assignment to an uncounted parameter ";
+      Os << "Assignment to an " << ptrKind() << " parameter ";
       printQuotedQualifiedName(Os, V);
       Os << " is unsafe.";
 
@@ -280,7 +283,7 @@ class UncountedLocalVarsChecker
       else
         Os << "Variable ";
       printQuotedQualifiedName(Os, V);
-      Os << " is uncounted and unsafe.";
+      Os << " is " << ptrKind() << " and unsafe.";
 
       PathDiagnosticLocation BSLoc(V->getLocation(), BR->getSourceManager());
       auto Report = std::make_unique<BasicBugReport>(Bug, Os.str(), BSLoc);
@@ -290,6 +293,29 @@ class UncountedLocalVarsChecker
     }
   }
 };
+
+class UncountedLocalVarsChecker final : public RawPtrRefLocalVarsChecker {
+public:
+  UncountedLocalVarsChecker()
+      : RawPtrRefLocalVarsChecker("Uncounted raw pointer or reference not "
+                                  "provably backed by ref-counted variable") {}
+  std::optional<bool> isUnsafePtr(const QualType T) const final {
+    return isUncountedPtr(T);
+  }
+  const char *ptrKind() const final { return "uncounted"; }
+};
+
+class UncheckedLocalVarsChecker final : public RawPtrRefLocalVarsChecker {
+public:
+  UncheckedLocalVarsChecker()
+      : RawPtrRefLocalVarsChecker("Unchecked raw pointer or reference not "
+                                  "provably backed by checked variable") {}
+  std::optional<bool> isUnsafePtr(const QualType T) const final {
+    return isUncheckedPtr(T);
+  }
+  const char *ptrKind() const final { return "unchecked"; }
+};
+
 } // namespace
 
 void ento::registerUncountedLocalVarsChecker(CheckerManager &Mgr) {
@@ -299,3 +325,11 @@ void ento::registerUncountedLocalVarsChecker(CheckerManager &Mgr) {
 bool ento::shouldRegisterUncountedLocalVarsChecker(const CheckerManager &) {
   return true;
 }
+
+void ento::registerUncheckedLocalVarsChecker(CheckerManager &Mgr) {
+  Mgr.registerChecker<UncheckedLocalVarsChecker>();
+}
+
+bool ento::shouldRegisterUncheckedLocalVarsChecker(const CheckerManager &) {
+  return true;
+}
diff --git a/clang/test/Analysis/Checkers/WebKit/mock-types.h b/clang/test/Analysis/Checkers/WebKit/mock-types.h
index 8d8a90f0afae0e..5aed6a403fe8f4 100644
--- a/clang/test/Analysis/Checkers/WebKit/mock-types.h
+++ b/clang/test/Analysis/Checkers/WebKit/mock-types.h
@@ -154,6 +154,8 @@ class CheckedObj {
 public:
   void incrementPtrCount();
   void decrementPtrCount();
+  void method();
+  int trivial() { return 123; }
 };
 
 class RefCountableAndCheckable {
diff --git a/clang/test/Analysis/Checkers/WebKit/unchecked-local-vars.cpp b/clang/test/Analysis/Checkers/WebKit/unchecked-local-vars.cpp
new file mode 100644
index 00000000000000..3bc75230fcf821
--- /dev/null
+++ b/clang/test/Analysis/Checkers/WebKit/unchecked-local-vars.cpp
@@ -0,0 +1,342 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.webkit.UncheckedLocalVarsChecker -verify %s
+
+#include "mock-types.h"
+#include "mock-system-header.h"
+
+void someFunction();
+
+namespace raw_ptr {
+void foo() {
+  CheckedObj *bar;
+  // FIXME: later on we might warn on uninitialized vars too
+}
+
+void bar(CheckedObj *) {}
+} // namespace raw_ptr
+
+namespace reference {
+void foo_ref() {
+  CheckedObj automatic;
+  CheckedObj &bar = automatic;
+  // expected-warning at -1{{Local variable 'bar' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  someFunction();
+  bar.method();
+}
+
+void foo_ref_trivial() {
+  CheckedObj automatic;
+  CheckedObj &bar = automatic;
+}
+
+void bar_ref(CheckedObj &) {}
+} // namespace reference
+
+namespace guardian_scopes {
+void foo1() {
+  CheckedPtr<CheckedObj> foo;
+  { CheckedObj *bar = foo.get(); }
+}
+
+void foo2() {
+  CheckedPtr<CheckedObj> foo;
+  // missing embedded scope here
+  CheckedObj *bar = foo.get();
+  // expected-warning at -1{{Local variable 'bar' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  someFunction();
+  bar->method();
+}
+
+void foo3() {
+  CheckedPtr<CheckedObj> foo;
+  {
+    { CheckedObj *bar = foo.get(); }
+  }
+}
+
+void foo4() {
+  {
+    CheckedPtr<CheckedObj> foo;
+    { CheckedObj *bar = foo.get(); }
+  }
+}
+
+void foo5() {
+  CheckedPtr<CheckedObj> foo;
+  auto* bar = foo.get();
+  bar->trivial();
+}
+
+void foo6() {
+  CheckedPtr<CheckedObj> foo;
+  auto* bar = foo.get();
+  // expected-warning at -1{{Local variable 'bar' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  bar->method();
+}
+
+struct SelfReferencingStruct {
+  SelfReferencingStruct* ptr;
+  CheckedObj* obj { nullptr };
+};
+
+void foo7(CheckedObj* obj) {
+  SelfReferencingStruct bar = { &bar, obj };
+  bar.obj->method();
+}
+
+} // namespace guardian_scopes
+
+namespace auto_keyword {
+class Foo {
+  CheckedObj *provide_ref_ctnbl();
+
+  void evil_func() {
+    CheckedObj *bar = provide_ref_ctnbl();
+    // expected-warning at -1{{Local variable 'bar' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    auto *baz = provide_ref_ctnbl();
+    // expected-warning at -1{{Local variable 'baz' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    auto *baz2 = this->provide_ref_ctnbl();
+    // expected-warning at -1{{Local variable 'baz2' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    [[clang::suppress]] auto *baz_suppressed = provide_ref_ctnbl(); // no-warning
+  }
+
+  void func() {
+    CheckedObj *bar = provide_ref_ctnbl();
+    // expected-warning at -1{{Local variable 'bar' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    if (bar)
+      bar->method();
+  }
+};
+} // namespace auto_keyword
+
+namespace guardian_casts {
+void foo1() {
+  CheckedPtr<CheckedObj> foo;
+  {
+    CheckedObj *bar = downcast<CheckedObj>(foo.get());
+    bar->method();
+  }
+  foo->method();
+}
+
+void foo2() {
+  CheckedPtr<CheckedObj> foo;
+  {
+    CheckedObj *bar =
+        static_cast<CheckedObj *>(downcast<CheckedObj>(foo.get()));
+    someFunction();
+  }
+}
+} // namespace guardian_casts
+
+namespace guardian_ref_conversion_operator {
+void foo() {
+  CheckedRef<CheckedObj> rc;
+  {
+    CheckedObj &rr = rc;
+    rr.method();
+    someFunction();
+  }
+}
+} // namespace guardian_ref_conversion_operator
+
+namespace ignore_for_if {
+CheckedObj *provide_ref_ctnbl() { return nullptr; }
+
+void foo() {
+  // no warnings
+  if (CheckedObj *a = provide_ref_ctnbl())
+    a->trivial();
+  for (CheckedObj *b = provide_ref_ctnbl(); b != nullptr;)
+    b->trivial();
+  CheckedObj *array[1];
+  for (CheckedObj *c : array)
+    c->trivial();
+  while (CheckedObj *d = provide_ref_ctnbl())
+    d->trivial();
+  do {
+    CheckedObj *e = provide_ref_ctnbl();
+    e->trivial();
+  } while (1);
+  someFunction();
+}
+
+void bar() {
+  if (CheckedObj *a = provide_ref_ctnbl()) {
+    // expected-warning at -1{{Local variable 'a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    a->method();    
+  }
+  for (CheckedObj *b = provide_ref_ctnbl(); b != nullptr;) {
+    // expected-warning at -1{{Local variable 'b' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    b->method();
+  }
+  CheckedObj *array[1];
+  for (CheckedObj *c : array) {
+    // expected-warning at -1{{Local variable 'c' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    c->method();
+  }
+
+  while (CheckedObj *d = provide_ref_ctnbl()) {
+    // expected-warning at -1{{Local variable 'd' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    d->method();
+  }
+  do {
+    CheckedObj *e = provide_ref_ctnbl();
+    // expected-warning at -1{{Local variable 'e' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    e->method();
+  } while (1);
+  someFunction();
+}
+
+} // namespace ignore_for_if
+
+namespace ignore_system_headers {
+
+CheckedObj *provide_checkable();
+
+void system_header() {
+  localVar<CheckedObj>(provide_checkable);
+}
+
+} // ignore_system_headers
+
+namespace conditional_op {
+CheckedObj *provide_checkable();
+bool bar();
+
+void foo() {
+  CheckedObj *a = bar() ? nullptr : provide_checkable();
+  // expected-warning at -1{{Local variable 'a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  CheckedPtr<CheckedObj> b = provide_checkable();
+  {
+    CheckedObj* c = bar() ? nullptr : b.get();
+    c->method();
+    CheckedObj* d = bar() ? b.get() : nullptr;
+    d->method();
+  }
+}
+
+} // namespace conditional_op
+
+namespace local_assignment_basic {
+
+CheckedObj *provide_checkable();
+
+void foo(CheckedObj* a) {
+  CheckedObj* b = a;
+  // expected-warning at -1{{Local variable 'b' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  if (b->trivial())
+    b = provide_checkable();
+}
+
+void bar(CheckedObj* a) {
+  CheckedObj* b;
+  // expected-warning at -1{{Local variable 'b' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  b = provide_checkable();
+}
+
+void baz() {
+  CheckedPtr a = provide_checkable();
+  {
+    CheckedObj* b = a.get();
+    // expected-warning at -1{{Local variable 'b' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    b = provide_checkable();
+  }
+}
+
+} // namespace local_assignment_basic
+
+namespace local_assignment_to_parameter {
+
+CheckedObj *provide_checkable();
+void someFunction();
+
+void foo(CheckedObj* a) {
+  a = provide_checkable();
+  // expected-warning at -1{{Assignment to an unchecked parameter 'a' is unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  someFunction();
+  a->method();
+}
+
+} // namespace local_assignment_to_parameter
+
+namespace local_assignment_to_static_local {
+
+CheckedObj *provide_checkable();
+void someFunction();
+
+void foo() {
+  static CheckedObj* a = nullptr;
+  // expected-warning at -1{{Static local variable 'a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  a = provide_checkable();
+  someFunction();
+  a->method();
+}
+
+} // namespace local_assignment_to_static_local
+
+namespace local_assignment_to_global {
+
+CheckedObj *provide_ref_cntbl();
+void someFunction();
+
+CheckedObj* g_a = nullptr;
+// expected-warning at -1{{Global variable 'local_assignment_to_global::g_a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+
+void foo() {
+  g_a = provide_ref_cntbl();
+  someFunction();
+  g_a->method();
+}
+
+} // namespace local_assignment_to_global
+
+namespace local_refcountable_checkable_object {
+
+RefCountableAndCheckable* provide_obj();
+
+void local_raw_ptr() {
+  RefCountableAndCheckable* a = nullptr;
+  // expected-warning at -1{{Local variable 'a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  a = provide_obj();
+  a->method();
+}
+
+void local_checked_ptr() {
+  RefPtr<RefCountableAndCheckable> a = nullptr;
+  a = provide_obj();
+  a->method();
+}
+
+void local_var_with_guardian_checked_ptr() {
+  RefPtr<RefCountableAndCheckable> a = provide_obj();
+  {
+    auto* b = a.get();
+    b->method();
+  }
+}
+
+void local_var_with_guardian_checked_ptr_with_assignment() {
+  RefPtr<RefCountableAndCheckable> a = provide_obj();
+  {
+    RefCountableAndCheckable* b = a.get();
+    // expected-warning at -1{{Local variable 'b' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+    b = provide_obj();
+    b->method();
+  }
+}
+
+void local_var_with_guardian_checked_ref() {
+  Ref<RefCountableAndCheckable> a = *provide_obj();
+  {
+    RefCountableAndCheckable& b = a;
+    b.method();
+  }
+}
+
+void static_var() {
+  static RefCountableAndCheckable* a = nullptr;
+  // expected-warning at -1{{Static local variable 'a' is unchecked and unsafe [alpha.webkit.UncheckedLocalVarsChecker]}}
+  a = provide_obj();
+}
+
+} // namespace local_refcountable_checkable_object
diff --git a/llvm/utils/gn/secondary/clang/lib/StaticAnalyzer/Checkers/BUILD.gn b/llvm/utils/gn/secondary/clang/lib/StaticAnalyzer/Checkers/BUILD.gn
index 7a6c360e88c14e..65600992e702d0 100644
--- a/llvm/utils/gn/secondary/clang/lib/StaticAnalyzer/Checkers/BUILD.gn
+++ b/llvm/utils/gn/secondary/clang/lib/StaticAnalyzer/Checkers/BUILD.gn
@@ -146,7 +146,7 @@ static_library("Checkers") {
     "WebKit/RefCntblBaseVirtualDtorChecker.cpp",
     "WebKit/UncountedCallArgsChecker.cpp",
     "WebKit/UncountedLambdaCapturesChecker.cpp",
-    "WebKit/UncountedLocalVarsChecker.cpp",
+    "WebKit/RawPtrRefLocalVarsChecker.cpp",
     "cert/InvalidPtrChecker.cpp",
   ]
 }

>From 7053b428098a780bd4807767d4b16e7f5b7c8007 Mon Sep 17 00:00:00 2001
From: Ryosuke Niwa <rniwa at webkit.org>
Date: Fri, 25 Oct 2024 09:41:22 -0700
Subject: [PATCH 2/2] Fix formatting.

---
 clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp | 3 +--
 .../Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp              | 2 +-
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
index 5d39d02a2f40f7..46819d5ca12058 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/PtrTypesSemantics.cpp
@@ -200,8 +200,7 @@ std::optional<bool> isUncountedPtr(const QualType T) {
   return false;
 }
 
-std::optional<bool> isUncheckedPtr(const QualType T)
-{
+std::optional<bool> isUncheckedPtr(const QualType T) {
   if (T->isPointerType() || T->isReferenceType()) {
     if (auto *CXXRD = T->getPointeeCXXRecordDecl())
       return isUnchecked(CXXRD);
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
index 0842cdbc4037b7..0781471d73cd3c 100644
--- a/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/RawPtrRefLocalVarsChecker.cpp
@@ -109,7 +109,7 @@ class RawPtrRefLocalVarsChecker
   mutable BugReporter *BR;
 
 public:
-  RawPtrRefLocalVarsChecker(const char* description)
+  RawPtrRefLocalVarsChecker(const char *description)
       : Bug(this, description, "WebKit coding guidelines") {}
 
   virtual std::optional<bool> isUnsafePtr(const QualType T) const = 0;



More information about the cfe-commits mailing list