[clang] 6026822 - bugfix in InfiniteLoopCheck to not print warnings for unevaluated loops

[usama hameed via cfe-commits]

Author: usama hameed
Date: 2022-05-23T20:18:48-07:00
New Revision: 602682225ad6c9135e84bbca3b91d5738712c64f

URL: https://github.com/llvm/llvm-project/commit/602682225ad6c9135e84bbca3b91d5738712c64f
DIFF: https://github.com/llvm/llvm-project/commit/602682225ad6c9135e84bbca3b91d5738712c64f.diff

LOG: bugfix in InfiniteLoopCheck to not print warnings for unevaluated loops

Differential Revision: https://reviews.llvm.org/D126034

Added: 
    

Modified: 
    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

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp b/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
index 3359a7f8932ed..cb9bd7bb43f50 100644
--- a/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
+++ b/clang-tools-extra/clang-tidy/bugprone/InfiniteLoopCheck.cpp
@@ -81,6 +81,22 @@ static bool isVarThatIsPossiblyChanged(const Decl *Func, const Stmt *LoopStmt,
   return false;
 }
 
+bool isUnevaluated(const Decl *Func, const Stmt *LoopStmt, const Stmt *Cond,
+                   ASTContext *Context) {
+  if (const auto *Exp = dyn_cast<Expr>(Cond)) {
+    if (const auto *ForLoop = dyn_cast<ForStmt>(LoopStmt)) {
+      return (ForLoop->getInc() && ExprMutationAnalyzer::isUnevaluated(
+                                       Exp, *ForLoop->getInc(), *Context)) ||
+             (ForLoop->getBody() && ExprMutationAnalyzer::isUnevaluated(
+                                        Exp, *ForLoop->getBody(), *Context)) ||
+             (ForLoop->getCond() && ExprMutationAnalyzer::isUnevaluated(
+                                        Exp, *ForLoop->getCond(), *Context));
+    }
+    return ExprMutationAnalyzer::isUnevaluated(Exp, *LoopStmt, *Context);
+  }
+  return true;
+}
+
 /// Return whether at least one variable of `Cond` changed in `LoopStmt`.
 static bool isAtLeastOneCondVarChanged(const Decl *Func, const Stmt *LoopStmt,
                                        const Stmt *Cond, ASTContext *Context) {
@@ -177,6 +193,9 @@ void InfiniteLoopCheck::check(const MatchFinder::MatchResult &Result) {
     }
   }
 
+  if (isUnevaluated(Func, LoopStmt, Cond, Result.Context))
+    return;
+
   if (isAtLeastOneCondVarChanged(Func, LoopStmt, Cond, Result.Context))
     return;
 

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp b/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
index 0074266ce4b87..a22f1bf06a534 100644
--- a/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
+++ b/clang-tools-extra/test/clang-tidy/checkers/bugprone-infinite-loop.cpp
@@ -650,3 +650,38 @@ void test_dependent_condition() {
   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;
+}

diff  --git a/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h b/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
index 9397c5df78abe..1b2b7ffcfb67a 100644
--- a/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
+++ b/clang/include/clang/Analysis/Analyses/ExprMutationAnalyzer.h
@@ -38,6 +38,8 @@ class ExprMutationAnalyzer {
   }
   const Stmt *findPointeeMutation(const Expr *Exp);
   const Stmt *findPointeeMutation(const Decl *Dec);
+  static bool isUnevaluated(const Expr *Exp, const Stmt &Stm,
+                            ASTContext &Context);
 
 private:
   using MutationFinder = const Stmt *(ExprMutationAnalyzer::*)(const Expr *);

diff  --git a/clang/lib/Analysis/ExprMutationAnalyzer.cpp b/clang/lib/Analysis/ExprMutationAnalyzer.cpp
index e9ff5e5e87658..4d7decc1137c2 100644
--- a/clang/lib/Analysis/ExprMutationAnalyzer.cpp
+++ b/clang/lib/Analysis/ExprMutationAnalyzer.cpp
@@ -194,7 +194,8 @@ const Stmt *ExprMutationAnalyzer::tryEachDeclRef(const Decl *Dec,
   return nullptr;
 }
 
-bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp) {
+bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp, const Stmt &Stm,
+                                         ASTContext &Context) {
   return selectFirst<Expr>(
              NodeID<Expr>::value,
              match(
@@ -225,6 +226,10 @@ bool ExprMutationAnalyzer::isUnevaluated(const Expr *Exp) {
                  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);