From a8e0cd8cdecc7e0ba1792e46773b884c6eed4829 Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Sat, 6 Aug 2011 07:30:58 +0000
Subject: [PATCH] Do l-value conversion, etc., on a switch condition expression
 in ActOnStartOfSwitchStmt (i.e. before binding up a full-expression) instead
 of ActOnFinishSwitchStmt.

Among other things, this means that property l-values are properly
converted inside the full-expression.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137014 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Sema/SemaCodeComplete.cpp |  9 +++++----
 lib/Sema/SemaStmt.cpp         | 35 ++++++++++++++++-------------------
 test/SemaObjC/arc.m           | 13 +++++++++++++
 3 files changed, 34 insertions(+), 23 deletions(-)

diff --git a/lib/Sema/SemaCodeComplete.cpp b/lib/Sema/SemaCodeComplete.cpp
index 5803a76600..cff9d6b4a9 100644
--- a/lib/Sema/SemaCodeComplete.cpp
+++ b/lib/Sema/SemaCodeComplete.cpp
@@ -3448,10 +3448,11 @@ void Sema::CodeCompleteTypeQualifiers(DeclSpec &DS) {
 void Sema::CodeCompleteCase(Scope *S) {
   if (getCurFunction()->SwitchStack.empty() || !CodeCompleter)
     return;
-  
+
   SwitchStmt *Switch = getCurFunction()->SwitchStack.back();
-  if (!Switch->getCond()->getType()->isEnumeralType()) {
-    CodeCompleteExpressionData Data(Switch->getCond()->getType());
+  QualType type = Switch->getCond()->IgnoreImplicit()->getType();
+  if (!type->isEnumeralType()) {
+    CodeCompleteExpressionData Data(type);
     Data.IntegralConstantExpression = true;
     CodeCompleteExpression(S, Data);
     return;
@@ -3459,7 +3460,7 @@ void Sema::CodeCompleteCase(Scope *S) {
   
   // Code-complete the cases of a switch statement over an enumeration type
   // by providing the list of 
-  EnumDecl *Enum = Switch->getCond()->getType()->getAs<EnumType>()->getDecl();
+  EnumDecl *Enum = type->castAs<EnumType>()->getDecl();
   
   // Determine which enumerators we have already seen in the switch statement.
   // FIXME: Ideally, we would also be able to look *past* the code-completion
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 6b2935fdf7..6e814e53bd 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -407,13 +407,12 @@ static bool EqEnumVals(const std::pair<llvm::APSInt, EnumConstantDecl*>& lhs,
 
 /// GetTypeBeforeIntegralPromotion - Returns the pre-promotion type of
 /// potentially integral-promoted expression @p expr.
-static QualType GetTypeBeforeIntegralPromotion(const Expr* expr) {
-  if (const CastExpr *ImplicitCast = dyn_cast<ImplicitCastExpr>(expr)) {
-    const Expr *ExprBeforePromotion = ImplicitCast->getSubExpr();
-    QualType TypeBeforePromotion = ExprBeforePromotion->getType();
-    if (TypeBeforePromotion->isIntegralOrEnumerationType()) {
-      return TypeBeforePromotion;
-    }
+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();
   }
   return expr->getType();
 }
@@ -449,6 +448,11 @@ Sema::ActOnStartOfSwitchStmt(SourceLocation SwitchLoc, Expr *Cond,
   if (CondResult.isInvalid()) return StmtError();
   Cond = CondResult.take();
 
+  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
+  CondResult = UsualUnaryConversions(Cond);
+  if (CondResult.isInvalid()) return StmtError();
+  Cond = CondResult.take();
+
   if (!CondVar) {
     CheckImplicitConversions(Cond, SwitchLoc);
     CondResult = MaybeCreateExprWithCleanups(Cond);
@@ -482,21 +486,14 @@ Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
   SS->setBody(BodyStmt, SwitchLoc);
   getCurFunction()->SwitchStack.pop_back();
 
-  if (SS->getCond() == 0)
-    return StmtError();
-
   Expr *CondExpr = SS->getCond();
-  Expr *CondExprBeforePromotion = CondExpr;
-  QualType CondTypeBeforePromotion =
-      GetTypeBeforeIntegralPromotion(CondExpr);
+  if (!CondExpr) return StmtError();
 
-  // C99 6.8.4.2p5 - Integer promotions are performed on the controlling expr.
-  ExprResult CondResult = UsualUnaryConversions(CondExpr);
-  if (CondResult.isInvalid())
-    return StmtError();
-  CondExpr = CondResult.take();
   QualType CondType = CondExpr->getType();
-  SS->setCond(CondExpr);
+
+  Expr *CondExprBeforePromotion = CondExpr;
+  QualType CondTypeBeforePromotion =
+      GetTypeBeforeIntegralPromotion(CondExprBeforePromotion);
 
   // C++ 6.4.2.p2:
   // Integral promotions are performed (on the switch condition).
diff --git a/test/SemaObjC/arc.m b/test/SemaObjC/arc.m
index 88d08181f6..83835ebd03 100644
--- a/test/SemaObjC/arc.m
+++ b/test/SemaObjC/arc.m
@@ -649,3 +649,16 @@ void test37(Test37 *c) {
     (void) y;
   }
 }
+
+// rdar://problem/9887979
+@interface Test38
+@property int value;
+@end
+void test38() {
+  extern Test38 *test38_helper(void);
+  switch (test38_helper().value) {
+  case 0:
+  case 1:
+    ;
+  }
+}
-- 
2.40.0