From 6b68dbf2e79df25f286bcd11805ae52093ba2b15 Mon Sep 17 00:00:00 2001
From: Fangrui Song <i@maskray.me>
Date: Sun, 27 Dec 2020 16:54:29 -0800
Subject: [PATCH] WIP. find icall

---
 .../bugprone/BugproneTidyModule.cpp           |  2 +
 .../clang-tidy/bugprone/CMakeLists.txt        |  1 +
 .../clang-tidy/bugprone/FindICallCheck.cpp    | 43 +++++++++++++++++++
 .../clang-tidy/bugprone/FindICallCheck.h      | 30 +++++++++++++
 4 files changed, 76 insertions(+)
 create mode 100644 clang-tools-extra/clang-tidy/bugprone/FindICallCheck.cpp
 create mode 100644 clang-tools-extra/clang-tidy/bugprone/FindICallCheck.h

diff --git a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
index 7f4d40f9701..c9a8f250766 100644
--- a/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/BugproneTidyModule.cpp
@@ -19,6 +19,7 @@
 #include "DanglingHandleCheck.h"
 #include "DynamicStaticInitializersCheck.h"
 #include "ExceptionEscapeCheck.h"
+#include "FindICallCheck.h"
 #include "FoldInitTypeCheck.h"
 #include "ForwardDeclarationNamespaceCheck.h"
 #include "ForwardingReferenceOverloadCheck.h"
@@ -161,6 +162,7 @@ public:
         "bugprone-suspicious-semicolon");
     CheckFactories.registerCheck<SuspiciousStringCompareCheck>(
         "bugprone-suspicious-string-compare");
+    CheckFactories.registerCheck<FindICallCheck>("bugprone-find-icall");
     CheckFactories.registerCheck<SwappedArgumentsCheck>(
         "bugprone-swapped-arguments");
     CheckFactories.registerCheck<TerminatingContinueCheck>(
diff --git a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
index b3684a5c101..2e52673069f 100644
--- a/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/bugprone/CMakeLists.txt
@@ -49,6 +49,7 @@ add_clang_library(clangTidyBugproneModule
   SuspiciousMissingCommaCheck.cpp
   SuspiciousSemicolonCheck.cpp
   SuspiciousStringCompareCheck.cpp
+  FindICallCheck.cpp
   SwappedArgumentsCheck.cpp
   TerminatingContinueCheck.cpp
   ThrowKeywordMissingCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.cpp
new file mode 100644
index 00000000000..81a3e87e0f6
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.cpp
@@ -0,0 +1,43 @@
+//===--- FindICallCheck.cpp - clang-tidy ---------------------------===//
+//
+// 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 "FindICallCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Tooling/FixIt.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+void FindICallCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(callExpr().bind("call"), this);
+}
+
+static const Expr *ignoreNoOpCasts(const Expr *E) {
+  if (auto *Cast = dyn_cast<CastExpr>(E))
+    if (Cast->getCastKind() != CK_LValueToRValue &&
+        Cast->getCastKind() != CK_FunctionToPointerDecay)
+      return ignoreNoOpCasts(Cast->getSubExpr());
+  return E;
+}
+
+void FindICallCheck::check(const MatchFinder::MatchResult &Result) {
+  const auto *Call = Result.Nodes.getNodeAs<CallExpr>("call");
+  if (auto *C = ignoreNoOpCasts(Call->getCallee()))
+    if (auto *Cast = dyn_cast<CastExpr>(C))
+      if (Cast->getCastKind() == CK_LValueToRValue)
+        diag(Call->getBeginLoc(), "%0") << C->getType();
+}
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
diff --git a/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.h b/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.h
new file mode 100644
index 00000000000..8becedee82f
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/bugprone/FindICallCheck.h
@@ -0,0 +1,30 @@
+//===--- SwappedArgumentsCheck.h - clang-tidy -------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_FINDICALLCHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_FINDICALLCHECK_H
+
+#include "../ClangTidyCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace bugprone {
+
+class FindICallCheck : public ClangTidyCheck {
+public:
+  FindICallCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace bugprone
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_FINDICALLCHECK_H
-- 
2.29.2