[clang-tidy] New util `Aliasing` factored out from `bugprone-infinite-loop`

Function `hasPtrOrReferenceInfFunc()` of `bugprone-infinite-loop` is a
generic function which could be reused in another checks. This patch
moves this function into a newly created utility module.

Differential Revision: https://reviews.llvm.org/D81396

diff --git a/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
index c9dd47e..310fbec 100644 (file)
--- a/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
@@ -10,8 +10,10 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchFinder.h"
 #include "clang/Analysis/Analyses/ExprMutationAnalyzer.h"
+#include "../utils/Aliasing.h"
 
 using namespace clang::ast_matchers;
+using clang::tidy::utils::hasPtrOrReferenceInFunc;
 
 namespace clang {
 namespace tidy {
@@ -24,54 +26,6 @@ loopEndingStmt(internal::Matcher<Stmt> Internal) {
                     callExpr(Internal, callee(functionDecl(isNoReturn())))));
 }
 
-/// Return whether `S` is a reference to the declaration of `Var`.
-static bool isAccessForVar(const Stmt *S, const VarDecl *Var) {
-  if (const auto *DRE = dyn_cast<DeclRefExpr>(S))
-    return DRE->getDecl() == Var;
-
-  return false;
-}
-
-/// Return whether `Var` has a pointer or reference in `S`.
-static bool isPtrOrReferenceForVar(const Stmt *S, const VarDecl *Var) {
-  if (const auto *DS = dyn_cast<DeclStmt>(S)) {
-    for (const Decl *D : DS->getDeclGroup()) {
-      if (const auto *LeftVar = dyn_cast<VarDecl>(D)) {
-        if (LeftVar->hasInit() && LeftVar->getType()->isReferenceType()) {
-          return isAccessForVar(LeftVar->getInit(), Var);
-        }
-      }
-    }
-  } else if (const auto *UnOp = dyn_cast<UnaryOperator>(S)) {
-    if (UnOp->getOpcode() == UO_AddrOf)
-      return isAccessForVar(UnOp->getSubExpr(), Var);
-  }
-
-  return false;
-}
-
-/// Return whether `Var` has a pointer or reference in `S`.
-static bool hasPtrOrReferenceInStmt(const Stmt *S, const VarDecl *Var) {
-  if (isPtrOrReferenceForVar(S, Var))
-    return true;
-
-  for (const Stmt *Child : S->children()) {
-    if (!Child)
-      continue;
-
-    if (hasPtrOrReferenceInStmt(Child, Var))
-      return true;
-  }
-
-  return false;
-}
-
-/// Return whether `Var` has a pointer or reference in `Func`.
-static bool hasPtrOrReferenceInFunc(const FunctionDecl *Func,
-                                    const VarDecl *Var) {
-  return hasPtrOrReferenceInStmt(Func->getBody(), Var);
-}
-
 /// Return whether `Var` was changed in `LoopStmt`.
 static bool isChanged(const Stmt *LoopStmt, const VarDecl *Var,
                       ASTContext *Context) {

diff --git a/clang-tools-extra/clang-tidy/utils/Aliasing.cpp b/clang-tools-extra/clang-tidy/utils/Aliasing.cpp
new file mode 100644 (file)
index 0000000..3a88126
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/utils/Aliasing.cpp
@@ -0,0 +1,65 @@
+//===------------- Aliasing.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 "Aliasing.h"
+
+#include "clang/AST/Expr.h"
+
+namespace clang {
+namespace tidy {
+namespace utils {
+
+/// Return whether \p S is a reference to the declaration of \p Var.
+static bool isAccessForVar(const Stmt *S, const VarDecl *Var) {
+  if (const auto *DRE = dyn_cast<DeclRefExpr>(S))
+    return DRE->getDecl() == Var;
+
+  return false;
+}
+
+/// Return whether \p Var has a pointer or reference in \p S.
+static bool isPtrOrReferenceForVar(const Stmt *S, const VarDecl *Var) {
+  if (const auto *DS = dyn_cast<DeclStmt>(S)) {
+    for (const Decl *D : DS->getDeclGroup()) {
+      if (const auto *LeftVar = dyn_cast<VarDecl>(D)) {
+        if (LeftVar->hasInit() && LeftVar->getType()->isReferenceType()) {
+          return isAccessForVar(LeftVar->getInit(), Var);
+        }
+      }
+    }
+  } else if (const auto *UnOp = dyn_cast<UnaryOperator>(S)) {
+    if (UnOp->getOpcode() == UO_AddrOf)
+      return isAccessForVar(UnOp->getSubExpr(), Var);
+  }
+
+  return false;
+}
+
+/// Return whether \p Var has a pointer or reference in \p S.
+static bool hasPtrOrReferenceInStmt(const Stmt *S, const VarDecl *Var) {
+  if (isPtrOrReferenceForVar(S, Var))
+    return true;
+
+  for (const Stmt *Child : S->children()) {
+    if (!Child)
+      continue;
+
+    if (hasPtrOrReferenceInStmt(Child, Var))
+      return true;
+  }
+
+  return false;
+}
+
+bool hasPtrOrReferenceInFunc(const FunctionDecl *Func, const VarDecl *Var) {
+  return hasPtrOrReferenceInStmt(Func->getBody(), Var);
+}
+
+} // namespace utils
+} // namespace tidy
+} // namespace clang

diff --git a/clang-tools-extra/clang-tidy/utils/Aliasing.h b/clang-tools-extra/clang-tidy/utils/Aliasing.h
new file mode 100644 (file)
index 0000000..e43995a
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/utils/Aliasing.h
@@ -0,0 +1,36 @@
+//===------------- Aliasing.h - 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_ALIASING_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_ALIASING_H
+
+#include "clang/AST/Decl.h"
+
+namespace clang {
+namespace tidy {
+namespace utils {
+
+/// Returns whether \p Var has a pointer or reference in \p Func.
+///
+/// Example:
+/// void f() {
+///   int n;
+///   ...
+///   int *p = &n;
+/// }
+///
+/// For `f()` and `n` the function returns ``true`` because `p` is a
+/// pointer to `n` created in `f()`.
+
+bool hasPtrOrReferenceInFunc(const FunctionDecl *Func, const VarDecl *Var);
+
+} // namespace utils
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_UTILS_ALIASING_H

diff --git a/clang-tools-extra/clang-tidy/utils/CMakeLists.txt b/clang-tools-extra/clang-tidy/utils/CMakeLists.txt
index e42d692..70edb9c 100644 (file)
--- a/clang-tools-extra/clang-tidy/utils/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/utils/CMakeLists.txt
@@ -4,6 +4,7 @@ set(LLVM_LINK_COMPONENTS
   )
 
 add_clang_library(clangTidyUtils
+  Aliasing.cpp
   ASTUtils.cpp
   DeclRefExprUtils.cpp
   ExceptionAnalyzer.cpp