commit 64c32411549e1ea94a0e0ba557b90fa4e962d328
author Gabor Horvath <xazax.hun@gmail.com> Wed Aug 09 08:57:09 2017 +0000
committer Gabor Horvath <xazax.hun@gmail.com> Wed Aug 09 08:57:09 2017 +0000
tree 4d6de269afc85d3d3282cae69df17096dedfc348
parent 34eeabbca3157958f62131fd4b7beeb4d9c203f8

[Sema] Extend -Wenum-compare to handle mixed enum comparisons in switch statements

Patch by: Reka Nikolett Kovacs

Differential Revision: https://reviews.llvm.org/D36407

llvm-svn: 310449

clang/lib/Sema/SemaStmt.cpp

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 2a38a1f..6bdc71b 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -602,14 +602,14 @@
 
 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
 /// potentially integral-promoted expression @p expr.
-static QualType GetTypeBeforeIntegralPromotion(Expr *&expr) {
-  if (ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(expr))
-    expr = cleanups->getSubExpr();
-  while (ImplicitCastExpr *impcast = dyn_cast<ImplicitCastExpr>(expr)) {
-    if (impcast->getCastKind() != CK_IntegralCast) break;
-    expr = impcast->getSubExpr();
+static QualType GetTypeBeforeIntegralPromotion(const Expr *&E) {
+  if (const auto *CleanUps = dyn_cast<ExprWithCleanups>(E))
+    E = CleanUps->getSubExpr();
+  while (const auto *ImpCast = dyn_cast<ImplicitCastExpr>(E)) {
+    if (ImpCast->getCastKind() != CK_IntegralCast) break;
+    E = ImpCast->getSubExpr();
   }
-  return expr->getType();
+  return E->getType();
 }
 
 ExprResult Sema::CheckSwitchCondition(SourceLocation SwitchLoc, Expr *Cond) {
@@ -743,6 +743,24 @@
   return true;
 }
 
+static void checkEnumTypesInSwitchStmt(Sema &S, const Expr *Cond,
+                                       const Expr *Case) {
+  QualType CondType = GetTypeBeforeIntegralPromotion(Cond);
+  QualType CaseType = Case->getType();
+
+  const EnumType *CondEnumType = CondType->getAs<EnumType>();
+  const EnumType *CaseEnumType = CaseType->getAs<EnumType>();
+  if (!CondEnumType || !CaseEnumType)
+    return;
+
+  if (S.Context.hasSameUnqualifiedType(CondType, CaseType))
+    return;
+
+  S.Diag(Case->getExprLoc(), diag::warn_comparison_of_mixed_enum_types)
+      << CondType << CaseType << Cond->getSourceRange()
+      << Case->getSourceRange();
+}
+
 StmtResult
 Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
                             Stmt *BodyStmt) {
@@ -760,7 +778,7 @@
 
   QualType CondType = CondExpr->getType();
 
-  Expr *CondExprBeforePromotion = CondExpr;
+  const Expr *CondExprBeforePromotion = CondExpr;
   QualType CondTypeBeforePromotion =
       GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
 
@@ -843,6 +861,8 @@
         break;
       }
 
+      checkEnumTypesInSwitchStmt(*this, CondExpr, Lo);
+
       llvm::APSInt LoVal;
 
       if (getLangOpts().CPlusPlus11) {