[clang-tidy] add abseil-unchecked-statusor-access

Pull Request: llvm#171188

Author: fmayer

clang-tools-extra/clang-tidy/abseil/AbseilTidyModule.cpp

@@ -27,6 +27,7 @@
 #include "StringFindStrContainsCheck.h"
 #include "TimeComparisonCheck.h"
 #include "TimeSubtractionCheck.h"
+#include "UncheckedStatusOrAccessCheck.h"
 #include "UpgradeDurationConversionsCheck.h"
 
 namespace clang::tidy {
@@ -67,6 +68,8 @@ class AbseilModule : public ClangTidyModule {
     CheckFactories.registerCheck<TimeComparisonCheck>("abseil-time-comparison");
     CheckFactories.registerCheck<TimeSubtractionCheck>(
         "abseil-time-subtraction");
+    CheckFactories.registerCheck<UncheckedStatusOrAccessCheck>(
+        "abseil-unchecked-statusor-access");
     CheckFactories.registerCheck<UpgradeDurationConversionsCheck>(
         "abseil-upgrade-duration-conversions");
   }

clang-tools-extra/clang-tidy/abseil/CMakeLists.txt

@@ -25,6 +25,7 @@ add_clang_library(clangTidyAbseilModule STATIC
   TimeComparisonCheck.cpp
   TimeSubtractionCheck.cpp
   UpgradeDurationConversionsCheck.cpp
+  UncheckedStatusOrAccessCheck.cpp
 
   LINK_LIBS
   clangTidy

clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.cpp

@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 "UncheckedStatusOrAccessCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/ASTMatchers/ASTMatchers.h"
+#include "clang/Analysis/FlowSensitive/DataflowAnalysis.h"
+#include "clang/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.h"
+#include "clang/Basic/SourceLocation.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/Error.h"
+
+namespace clang::tidy::abseil {
+using ast_matchers::MatchFinder;
+using dataflow::statusor_model::UncheckedStatusOrAccessDiagnoser;
+using dataflow::statusor_model::UncheckedStatusOrAccessModel;
+
+static constexpr llvm::StringLiteral FuncID("fun");
+
+void UncheckedStatusOrAccessCheck::registerMatchers(MatchFinder *Finder) {
+  using namespace ast_matchers;
+
+  auto HasStatusOrCallDescendant =
+      hasDescendant(callExpr(callee(cxxMethodDecl(ofClass(hasAnyName(
+          "absl::StatusOr", "absl::internal_statusor::OperatorBase"))))));
+  Finder->addMatcher(functionDecl(unless(isExpansionInSystemHeader()),
+                                  hasBody(HasStatusOrCallDescendant))
+                         .bind(FuncID),
+                     this);
+  Finder->addMatcher(
+      cxxConstructorDecl(hasAnyConstructorInitializer(
+                             withInitializer(HasStatusOrCallDescendant)))
+          .bind(FuncID),
+      this);
+}
+
+void UncheckedStatusOrAccessCheck::check(
+    const MatchFinder::MatchResult &Result) {
+  if (Result.SourceManager->getDiagnostics().hasUncompilableErrorOccurred())
+    return;
+
+  const auto *FuncDecl = Result.Nodes.getNodeAs<FunctionDecl>(FuncID);
+  if (FuncDecl->isTemplated())
+    return;
+
+  UncheckedStatusOrAccessDiagnoser Diagnoser;
+  if (llvm::Expected<llvm::SmallVector<SourceLocation>> Locs =
+          dataflow::diagnoseFunction<UncheckedStatusOrAccessModel,
+                                     SourceLocation>(*FuncDecl, *Result.Context,
+                                                     Diagnoser))
+    for (const SourceLocation &Loc : *Locs)
+      diag(Loc, "unchecked access to 'absl::StatusOr' value");
+  else
+    llvm::consumeError(Locs.takeError());
+}
+
+bool UncheckedStatusOrAccessCheck::isLanguageVersionSupported(
+    const LangOptions &LangOpts) const {
+  return LangOpts.CPlusPlus;
+}
+
+} // namespace clang::tidy::abseil

clang-tools-extra/clang-tidy/abseil/UncheckedStatusOrAccessCheck.h

@@ -0,0 +1,24 @@
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_UNCHECKEDSTATUSORACCESSCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_UNCHECKEDSTATUSORACCESSCHECK_H
+
+#include "../ClangTidyCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+namespace clang::tidy::abseil {
+
+// Warns when the code is unwrapping an absl::StatusOr<T> object without
+// assuring that it contains a value.
+//
+// For details on the dataflow analysis implemented in this check see:
+// clang/lib/Analysis/FlowSensitive/Models/UncheckedStatusOrAccessModel.cpp
+class UncheckedStatusOrAccessCheck : public ClangTidyCheck {
+public:
+  using ClangTidyCheck::ClangTidyCheck;
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override;
+};
+
+} // namespace clang::tidy::abseil
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_UNCHECKEDSTATUSORACCESSCHECK_H

clang-tools-extra/docs/ReleaseNotes.rst

@@ -214,6 +214,11 @@ Improvements to clang-tidy
 New checks
 ^^^^^^^^^^
 
+- New :doc:`abseil-unchecked-statusor-access
+  <clang-tidy/checks/abseil/unchecked-statusor-access>` check.
+
+  Finds uses of ``absl::StatusOr`` without checking if a value is present.
+
 - New :doc:`bugprone-derived-method-shadowing-base-method
   <clang-tidy/checks/bugprone/derived-method-shadowing-base-method>` check.