[PATCH] D126034: [clang-tidy] bugfix in InfiniteLoopCheck to not print warnings for unevaluated loops

[Usama Hameed via Phabricator via cfe-commits]

usama54321 updated this revision to Diff 431516.
usama54321 added a comment.

- updated canResolveToExpr to accept both statements and expressions. Removed 
unnecessary code


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D126034/new/

https://reviews.llvm.org/D126034

Files:
  clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
  clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
  clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
  clang/lib/Analysis/ExprMutationAnalyzer.cpp


Index: clang/lib/Analysis/ExprMutationAnalyzer.cpp
===================================================================
--- clang/lib/Analysis/ExprMutationAnalyzer.cpp
+++ clang/lib/Analysis/ExprMutationAnalyzer.cpp
@@ -39,8 +39,13 @@
   return InnerMatcher.matches(*Result, Finder, Builder);
 }
 
-AST_MATCHER_P(Expr, canResolveToExpr, ast_matchers::internal::Matcher<Expr>,
+AST_MATCHER_P(Stmt, canResolveToExpr, ast_matchers::internal::Matcher<Stmt>,
               InnerMatcher) {
+  auto *Exp = dyn_cast<Expr>(&Node);
+  if (!Exp) {
+    return stmt().matches(Node, Finder, Builder);
+  }
+
   auto DerivedToBase = [](const ast_matchers::internal::Matcher<Expr> &Inner) {
     return implicitCastExpr(anyOf(hasCastKind(CK_DerivedToBase),
                                   hasCastKind(CK_UncheckedDerivedToBase)),
@@ -71,7 +76,7 @@
                  IgnoreDerivedToBase(ConditionalOperator),
                  IgnoreDerivedToBase(ElvisOperator))));
 
-  return ComplexMatcher.matches(Node, Finder, Builder);
+  return ComplexMatcher.matches(*Exp, Finder, Builder);
 }
 
 // Similar to 'hasAnyArgument', but does not work because 'InitListExpr' does
@@ -194,12 +199,13 @@
   return nullptr;
 }
 
-bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp) {
-  return selectFirst<Expr>(
+bool ExprMutationAnalyzer::isUnevaluated(const Stmt *Exp, const Stmt &Stm,
+                                         ASTContext &Context) {
+  return selectFirst<Stmt>(
              NodeID<Expr>::value,
              match(
                  findAll(
-                     expr(canResolveToExpr(equalsNode(Exp)),
+                     stmt(canResolveToExpr(equalsNode(Exp)),
                           anyOf(
                               // `Exp` is part of the underlying expression of
                               // decltype/typeof if it has an ancestor of
@@ -225,6 +231,10 @@
                  Stm, Context)) != nullptr;
 }
 
+bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp) {
+  return isUnevaluated(Exp, Stm, Context);
+}
+
 const Stmt *
 ExprMutationAnalyzer::findExprMutation(ArrayRef<BoundNodes> Matches) {
   return tryEachMatch<Expr>(Matches, this, &ExprMutationAnalyzer::findMutation);
Index: clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
===================================================================
--- clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
+++ clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
@@ -38,6 +38,8 @@
   }
   const Stmt *findPointeeMutation(const Expr *Exp);
   const Stmt *findPointeeMutation(const Decl *Dec);
+  static bool isUnevaluated(const Stmt *Smt, const Stmt &Stm,
+                            ASTContext &Context);
 
 private:
   using MutationFinder = const Stmt *(ExprMutationAnalyzer::*)(const Expr *);
Index: clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
===================================================================
--- clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
+++ clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
@@ -650,3 +650,38 @@
   do {
   } while (1, (false) && val4 == 1);
 }
+
+void test_typeof() {
+  __typeof__({
+    for (int i = 0; i < 10; ++i) {
+    }
+    0;
+  }) x;
+}
+
+void test_typeof_infinite() {
+  __typeof__({
+    for (int i = 0; i < 10;) {
+    }
+    0;
+  }) x;
+}
+
+void test_typeof_while_infinite() {
+  __typeof__({
+    int i = 0;
+    while (i < 10) {
+    }
+    0;
+  }) x;
+}
+
+void test_typeof_dowhile_infinite() {
+  __typeof__({
+    int i = 0;
+    do {
+
+    } while (i < 10);
+    0;
+  }) x;
+}
Index: clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
===================================================================
--- clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
+++ clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
@@ -177,6 +177,9 @@
     }
   }
 
+  if (ExprMutationAnalyzer::isUnevaluated(LoopStmt, *LoopStmt, *Result.Context))
+    return;
+
   if (isAtLeastOneCondVarChanged(Func, LoopStmt, Cond, Result.Context))
     return;
 

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