1 files changed, 195 insertions, 0 deletions
diff --git a/clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedCallArgsChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedCallArgsChecker.cpp
new file mode 100644
index 000000000000..940a1f349831
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/WebKit/UncountedCallArgsChecker.cpp
@@ -0,0 +1,195 @@
+//=======- UncountedCallArgsChecker.cpp --------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "ASTUtils.h"
+#include "DiagOutputUtils.h"
+#include "PtrTypesSemantics.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "llvm/ADT/DenseSet.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class UncountedCallArgsChecker
+    : public Checker<check::ASTDecl<TranslationUnitDecl>> {
+  BugType Bug{this,
+            "Uncounted call argument for a raw pointer/reference parameter",
+            "WebKit coding guidelines"};
+  mutable BugReporter *BR;
+
+public:
+
+  void checkASTDecl(const TranslationUnitDecl *TUD, AnalysisManager &MGR,
+                    BugReporter &BRArg) const {
+    BR = &BRArg;
+
+    // The calls to checkAST* from AnalysisConsumer don't
+    // visit template instantiations or lambda classes. We
+    // want to visit those, so we make our own RecursiveASTVisitor.
+    struct LocalVisitor : public RecursiveASTVisitor<LocalVisitor> {
+      const UncountedCallArgsChecker *Checker;
+      explicit LocalVisitor(const UncountedCallArgsChecker *Checker)
+          : Checker(Checker) {
+        assert(Checker);
+      }
+
+      bool shouldVisitTemplateInstantiations() const { return true; }
+      bool shouldVisitImplicitCode() const { return false; }
+
+      bool VisitCallExpr(const CallExpr *CE) {
+        Checker->visitCallExpr(CE);
+        return true;
+      }
+    };
+
+    LocalVisitor visitor(this);
+    visitor.TraverseDecl(const_cast<TranslationUnitDecl *>(TUD));
+  }
+
+  void visitCallExpr(const CallExpr *CE) const {
+    if (shouldSkipCall(CE))
+      return;
+
+    if (auto *F = CE->getDirectCallee()) {
+      // Skip the first argument for overloaded member operators (e. g. lambda
+      // or std::function call operator).
+      unsigned ArgIdx =
+          isa<CXXOperatorCallExpr>(CE) && dyn_cast_or_null<CXXMethodDecl>(F);
+
+      for (auto P = F->param_begin();
+           // FIXME: Also check variadic function parameters.
+           // FIXME: Also check default function arguments. Probably a different
+           // checker. In case there are default arguments the call can have
+           // fewer arguments than the callee has parameters.
+           P < F->param_end() && ArgIdx < CE->getNumArgs(); ++P, ++ArgIdx) {
+        // TODO: attributes.
+        // if ((*P)->hasAttr<SafeRefCntblRawPtrAttr>())
+        //  continue;
+
+        const auto *ArgType = (*P)->getType().getTypePtrOrNull();
+        if (!ArgType)
+          continue; // FIXME? Should we bail?
+
+        // FIXME: more complex types (arrays, references to raw pointers, etc)
+        if (!isUncountedPtr(ArgType))
+          continue;
+
+        const auto *Arg = CE->getArg(ArgIdx);
+
+        std::pair<const clang::Expr *, bool> ArgOrigin =
+            tryToFindPtrOrigin(Arg, true);
+
+        // Temporary ref-counted object created as part of the call argument
+        // would outlive the call.
+        if (ArgOrigin.second)
+          continue;
+
+        if (isa<CXXNullPtrLiteralExpr>(ArgOrigin.first)) {
+          // foo(nullptr)
+          continue;
+        }
+        if (isa<IntegerLiteral>(ArgOrigin.first)) {
+          // FIXME: Check the value.
+          // foo(NULL)
+          continue;
+        }
+
+        if (isASafeCallArg(ArgOrigin.first))
+          continue;
+
+        reportBug(Arg, *P);
+      }
+    }
+  }
+
+  bool shouldSkipCall(const CallExpr *CE) const {
+    if (CE->getNumArgs() == 0)
+      return false;
+
+    // If an assignment is problematic we should warn about the sole existence
+    // of object on LHS.
+    if (auto *MemberOp = dyn_cast<CXXOperatorCallExpr>(CE)) {
+      // Note: assignemnt to built-in type isn't derived from CallExpr.
+      if (MemberOp->isAssignmentOp())
+        return false;
+    }
+
+    const auto *Callee = CE->getDirectCallee();
+    if (!Callee)
+      return false;
+
+    auto overloadedOperatorType = Callee->getOverloadedOperator();
+    if (overloadedOperatorType == OO_EqualEqual ||
+        overloadedOperatorType == OO_ExclaimEqual ||
+        overloadedOperatorType == OO_LessEqual ||
+        overloadedOperatorType == OO_GreaterEqual ||
+        overloadedOperatorType == OO_Spaceship ||
+        overloadedOperatorType == OO_AmpAmp ||
+        overloadedOperatorType == OO_PipePipe)
+      return true;
+
+    if (isCtorOfRefCounted(Callee))
+      return true;
+
+    auto name = safeGetName(Callee);
+    if (name == "adoptRef" || name == "getPtr" || name == "WeakPtr" ||
+        name == "makeWeakPtr" || name == "downcast" || name == "bitwise_cast" ||
+        name == "is" || name == "equal" || name == "hash" ||
+        name == "isType"
+        // FIXME: Most/all of these should be implemented via attributes.
+        || name == "equalIgnoringASCIICase" ||
+        name == "equalIgnoringASCIICaseCommon" ||
+        name == "equalIgnoringNullity")
+      return true;
+
+    return false;
+  }
+
+  void reportBug(const Expr *CallArg, const ParmVarDecl *Param) const {
+    assert(CallArg);
+
+    SmallString<100> Buf;
+    llvm::raw_svector_ostream Os(Buf);
+
+    const std::string paramName = safeGetName(Param);
+    Os << "Call argument";
+    if (!paramName.empty()) {
+      Os << " for parameter ";
+      printQuotedQualifiedName(Os, Param);
+    }
+    Os << " is uncounted and unsafe.";
+
+    const SourceLocation SrcLocToReport =
+        isa<CXXDefaultArgExpr>(CallArg) ? Param->getDefaultArg()->getExprLoc()
+                                        : CallArg->getSourceRange().getBegin();
+
+    PathDiagnosticLocation BSLoc(SrcLocToReport, BR->getSourceManager());
+    auto Report = std::make_unique<BasicBugReport>(Bug, Os.str(), BSLoc);
+    Report->addRange(CallArg->getSourceRange());
+    BR->emitReport(std::move(Report));
+  }
+};
+} // namespace
+
+void ento::registerUncountedCallArgsChecker(CheckerManager &Mgr) {
+  Mgr.registerChecker<UncountedCallArgsChecker>();
+}
+
+bool ento::shouldRegisterUncountedCallArgsChecker(const CheckerManager &) {
+  return true;
+}