[clang-tidy] ExprMutationAnalyzer: construct from references. Fixes PR38888

Summary:
I have hit this the rough way, while trying to use this in D51870.

There is no particular point in storing the pointers, and moreover
the pointers are assumed to be non-null, and that assumption is not
enforced. If they are null, it won't be able to do anything good
with them anyway.

Initially i thought about simply adding asserts() that they are
not null, but taking/storing references looks like even cleaner solution?

Fixes [[ https://bugs.llvm.org/show_bug.cgi?id=38888 | PR38888 ]]

Reviewers: JonasToth, shuaiwang, alexfh, george.karpenkov

Reviewed By: shuaiwang

Subscribers: xazax.hun, a.sidorin, Szelethus, cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D51884

llvm-svn: 341854

2 files changed, 11 insertions, 11 deletions

diff --git a/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.cpp b/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.cpp
index f1cd1daf577..f979e97a03d 100644
--- a/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.cpp
+++ b/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.cpp
@@ -102,7 +102,7 @@ bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp) {
                                       hasDescendant(equalsNode(Exp)))),
                                   cxxNoexceptExpr())))))
                          .bind("expr")),
-                 *Stm, *Context)) != nullptr;
+                 Stm, Context)) != nullptr;
 }
 
 const Stmt *
@@ -125,7 +125,7 @@ ExprMutationAnalyzer::findDeclMutation(ArrayRef<BoundNodes> Matches) {
 
 const Stmt *ExprMutationAnalyzer::findDeclMutation(const Decl *Dec) {
   const auto Refs = match(
-      findAll(declRefExpr(to(equalsNode(Dec))).bind("expr")), *Stm, *Context);
+      findAll(declRefExpr(to(equalsNode(Dec))).bind("expr")), Stm, Context);
   for (const auto &RefNodes : Refs) {
     const auto *E = RefNodes.getNodeAs<Expr>("expr");
     if (findMutation(E))
@@ -200,7 +200,7 @@ const Stmt *ExprMutationAnalyzer::findDirectMutation(const Expr *Exp) {
                                AsNonConstRefArg, AsLambdaRefCaptureInit,
                                AsNonConstRefReturn))
                         .bind("stmt")),
-            *Stm, *Context);
+            Stm, Context);
   return selectFirst<Stmt>("stmt", Matches);
 }
 
@@ -211,7 +211,7 @@ const Stmt *ExprMutationAnalyzer::findMemberMutation(const Expr *Exp) {
                                cxxDependentScopeMemberExpr(
                                    hasObjectExpression(equalsNode(Exp)))))
                         .bind("expr")),
-            *Stm, *Context);
+            Stm, Context);
   return findExprMutation(MemberExprs);
 }
 
@@ -220,7 +220,7 @@ const Stmt *ExprMutationAnalyzer::findArrayElementMutation(const Expr *Exp) {
   const auto SubscriptExprs = match(
       findAll(arraySubscriptExpr(hasBase(ignoringImpCasts(equalsNode(Exp))))
                   .bind("expr")),
-      *Stm, *Context);
+      Stm, Context);
   return findExprMutation(SubscriptExprs);
 }
 
@@ -233,7 +233,7 @@ const Stmt *ExprMutationAnalyzer::findCastMutation(const Expr *Exp) {
                                    implicitCastExpr(hasImplicitDestinationType(
                                        nonConstReferenceType()))))
                         .bind("expr")),
-            *Stm, *Context);
+            Stm, Context);
   return findExprMutation(Casts);
 }
 
@@ -245,7 +245,7 @@ const Stmt *ExprMutationAnalyzer::findRangeLoopMutation(const Expr *Exp) {
                 hasLoopVariable(
                     varDecl(hasType(nonConstReferenceType())).bind("decl")),
                 hasRangeInit(equalsNode(Exp)))),
-            *Stm, *Context);
+            Stm, Context);
   return findDeclMutation(LoopVars);
 }
 
@@ -265,7 +265,7 @@ const Stmt *ExprMutationAnalyzer::findReferenceMutation(const Expr *Exp) {
               unless(hasParent(declStmt(hasParent(
                   cxxForRangeStmt(hasRangeStmt(equalsBoundNode("stmt"))))))))
               .bind("decl"))),
-      *Stm, *Context);
+      Stm, Context);
   return findDeclMutation(Refs);
 }
 
diff --git a/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.h b/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.h
index 256bb712891..e295de9bb88 100644
--- a/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.h
+++ b/clang-tools-extra/clang-tidy/utils/ExprMutationAnalyzer.h
@@ -23,7 +23,7 @@ namespace utils {
 /// a given statement.
 class ExprMutationAnalyzer {
 public:
-  ExprMutationAnalyzer(const Stmt *Stm, ASTContext *Context)
+  ExprMutationAnalyzer(const Stmt &Stm, ASTContext &Context)
       : Stm(Stm), Context(Context) {}
 
   bool isMutated(const Decl *Dec) { return findDeclMutation(Dec) != nullptr; }
@@ -44,8 +44,8 @@ private:
   const Stmt *findRangeLoopMutation(const Expr *Exp);
   const Stmt *findReferenceMutation(const Expr *Exp);
 
-  const Stmt *const Stm;
-  ASTContext *const Context;
+  const Stmt &Stm;
+  ASTContext &Context;
   llvm::DenseMap<const Expr *, const Stmt *> Results;
 };