From: Douglas Gregor <dgregor@apple.com>
Date: Thu, 9 Feb 2012 00:47:04 +0000 (+0000)
Subject: Various interrelated cleanups for lambdas:
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=503384f731b5abcbf870b0a5224eb920e631db0a;p=clang

Various interrelated cleanups for lambdas:
  - Complete the lambda class when we finish the lambda expression
    (previously, it was left in the "being completed" state)
  - Actually return the LambdaExpr object and bind to the resulting
  temporary when needed.
  - Detect when cleanups are needed while capturing a variable into a
  lambda (e.g., due to default arguments in the copy constructor), and
  make sure those cleanups apply for the whole of the lambda
  expression.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150123 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Sema/ScopeInfo.h b/include/clang/Sema/ScopeInfo.h
index d1e47b2b2f..91f468b3e5 100644
--- a/include/clang/Sema/ScopeInfo.h
+++ b/include/clang/Sema/ScopeInfo.h
@@ -290,15 +290,20 @@ public:
   /// explicit captures.
   unsigned NumExplicitCaptures;
 
+  /// \brief Whether this is a mutable lambda.
   bool Mutable;
   
   /// \brief Whether the (empty) parameter list is explicit.
   bool ExplicitParams;
 
+  /// \brief Whether any of the capture expressions requires cleanups.
+  bool ExprNeedsCleanups;
+
   LambdaScopeInfo(DiagnosticsEngine &Diag, CXXRecordDecl *Lambda,
                   CXXMethodDecl *CallOperator)
     : CapturingScopeInfo(Diag, ImpCap_None), Lambda(Lambda),
-      CallOperator(CallOperator), NumExplicitCaptures(0), Mutable(false)
+      CallOperator(CallOperator), NumExplicitCaptures(0), Mutable(false),
+      ExprNeedsCleanups(false)
   {
     Kind = SK_Lambda;
   }
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 378930a0e5..69731e45ef 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -4185,7 +4185,10 @@ void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
   BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
   bool IsLogicalOperator = BO && BO->isLogicalOp();
   for (Stmt::child_range I = E->children(); I; ++I) {
-    Expr *ChildExpr = cast<Expr>(*I);
+    Expr *ChildExpr = dyn_cast<Expr>(*I);
+    if (!ChildExpr)
+      continue;
+
     if (IsLogicalOperator &&
         isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
       // Ignore checking string literals that are in logical operators.
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index accf85171e..aed6eaf4e3 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9652,7 +9652,8 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
     Expr *copyExpr = 0;
     const RecordType *rtype;
     if (isLambda) {
-      CXXRecordDecl *Lambda = cast<LambdaScopeInfo>(CSI)->Lambda;
+      LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CSI);
+      CXXRecordDecl *Lambda = LSI->Lambda;
       QualType FieldType;
       if (byRef) {
         // C++11 [expr.prim.lambda]p15:
@@ -9704,6 +9705,11 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
       //
       // FIXME: Introduce an initialization entity for lambda captures.
       // FIXME: Totally broken for arrays.
+      
+      // Introduce a new evaluation context for the initialization, so that
+      // temporaries introduced as part of the capture
+      PushExpressionEvaluationContext(PotentiallyEvaluated);
+
       Expr *Ref = new (Context) DeclRefExpr(var, type.getNonReferenceType(),
                                             VK_LValue, loc);
       InitializedEntity InitEntity
@@ -9717,6 +9723,17 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
         if (!Result.isInvalid())
           copyExpr = Result.take();
       }
+
+      // If this initialization requires any cleanups (e.g., due to a
+      // default argument to a copy constructor), note that for the
+      // lambda.
+      if (ExprNeedsCleanups)
+        LSI->ExprNeedsCleanups = true;
+
+      // Exit the expression evaluation context used for the capture.
+      CleanupVarDeclMarking();
+      DiscardCleanupsInEvaluationContext();
+      PopExpressionEvaluationContext();
     } else if (!byRef && getLangOptions().CPlusPlus &&
         (rtype = type.getNonReferenceType()->getAs<RecordType>())) {
       // The capture logic needs the destructor, so make sure we mark it.
diff --git a/lib/Sema/SemaLambda.cpp b/lib/Sema/SemaLambda.cpp
index 3e9e210244..b90f5e3d63 100644
--- a/lib/Sema/SemaLambda.cpp
+++ b/lib/Sema/SemaLambda.cpp
@@ -103,13 +103,11 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
   Method->setAccess(AS_public);
   Class->addDecl(Method);
   Method->setLexicalDeclContext(DC); // FIXME: Minor hack.
-  
+
+  // Attributes on the lambda apply to the method.  
   ProcessDeclAttributes(CurScope, Method, ParamInfo);
   
-  // Enter a new evaluation context to insulate the block from any
-  // cleanups from the enclosing full-expression.
-  PushExpressionEvaluationContext(PotentiallyEvaluated);
-  
+  // Introduce the function call operator as the current declaration context.
   PushDeclContext(CurScope, Method);
     
   // Introduce the lambda scope.
@@ -255,6 +253,9 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
 
   // FIXME: Check return type is complete, !isObjCObjectType
   
+  // Enter a new evaluation context to insulate the block from any
+  // cleanups from the enclosing full-expression.
+  PushExpressionEvaluationContext(PotentiallyEvaluated);  
 }
 
 void Sema::ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope) {
@@ -273,8 +274,6 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
   DiscardCleanupsInEvaluationContext();
   PopExpressionEvaluationContext();
 
-  // FIXME: End-of-lambda checking
-
   // Collect information from the lambda scope.
   llvm::SmallVector<LambdaExpr::Capture, 4> Captures;
   llvm::SmallVector<Expr *, 4> CaptureInits;
@@ -282,11 +281,13 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
   CXXRecordDecl *Class;
   SourceRange IntroducerRange;
   bool ExplicitParams;
+  bool LambdaExprNeedsCleanups;
   {
     LambdaScopeInfo *LSI = getCurLambda();
     Class = LSI->Lambda;
     IntroducerRange = LSI->IntroducerRange;
     ExplicitParams = LSI->ExplicitParams;
+    LambdaExprNeedsCleanups = LSI->ExprNeedsCleanups;
 
     // Translate captures.
     for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
@@ -331,16 +332,25 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
       break;
     }
 
+    // Finalize the lambda class.
+    SmallVector<Decl*, 4> Fields(Class->field_begin(), Class->field_end());
+    ActOnFields(0, Class->getLocation(), Class, Fields, 
+                SourceLocation(), SourceLocation(), 0);
+    CheckCompletedCXXClass(Class);
+
     // C++ [expr.prim.lambda]p7:
     //   The lambda-expression's compound-statement yields the
     //   function-body (8.4) of the function call operator [...].
     ActOnFinishFunctionBody(LSI->CallOperator, Body, /*IsInstantation=*/false);
   }
 
+  if (LambdaExprNeedsCleanups)
+    ExprNeedsCleanups = true;
+
   Expr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange, 
                                     CaptureDefault, Captures, ExplicitParams, 
                                     CaptureInits, Body->getLocEnd());
-  (void)Lambda;
   Diag(StartLoc, diag::err_lambda_unsupported);
-  return ExprError();
+
+  return MaybeBindToTemporary(Lambda);
 }
diff --git a/test/CXX/class/class.local/p1-0x.cpp b/test/CXX/class/class.local/p1-0x.cpp
index 8916295825..b8e1f68000 100644
--- a/test/CXX/class/class.local/p1-0x.cpp
+++ b/test/CXX/class/class.local/p1-0x.cpp
@@ -7,12 +7,12 @@ void f() {
     int& x2 = x; // expected-error{{reference to local variable 'x' declared in enclosing function 'f'}}
     int cc = c;
   };
-  []() mutable { // expected-error {{not supported yet}}
+  (void)[]() mutable { // expected-error {{not supported yet}}
     int x = 3; // expected-note{{'x' declared here}}
     struct C {
       int& x2 = x; // expected-error{{reference to local variable 'x' declared in enclosing lambda expression}}
     };
-  }
+  };
   C();
 }
 
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p10.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p10.cpp
index 497307ff75..6f09c53e57 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p10.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p10.cpp
@@ -1,6 +1,6 @@
 // RUN: %clang_cc1 -std=c++11 %s -verify
 
-int GlobalVar; // expected-note 2{{declared here}}
+int GlobalVar; // expected-note {{declared here}}
 
 namespace N {
   int AmbiguousVar; // expected-note {{candidate}}
@@ -16,9 +16,11 @@ class X0 {
   virtual X0& Overload(float);
 
   void explicit_capture() {
-    [&Overload] () {}; // expected-error {{does not name a variable}} expected-error {{not supported yet}}
-    [&GlobalVar] () {}; // expected-error {{does not have automatic storage duration}} expected-error {{not supported yet}}
-    [&AmbiguousVar] () {} // expected-error {{reference to 'AmbiguousVar' is ambiguous}} expected-error {{not supported yet}}
-    [&Globalvar] () {}; // expected-error {{use of undeclared identifier 'Globalvar'; did you mean 'GlobalVar}}
+    int variable; // expected-note {{declared here}}
+    (void)[&Overload] () {}; // expected-error {{does not name a variable}} expected-error {{not supported yet}}
+    (void)[&GlobalVar] () {}; // expected-error {{does not have automatic storage duration}} expected-error {{not supported yet}}
+    (void)[&AmbiguousVar] () {}; // expected-error {{reference to 'AmbiguousVar' is ambiguous}} expected-error {{not supported yet}}
+    (void)[&Variable] () {}; // expected-error {{use of undeclared identifier 'Variable'; did you mean 'variable'}} \
+    // expected-error{{lambda expressions are not supported yet}}
   }
 };
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p14.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p14.cpp
index 0bbb9ae744..4c876d7480 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p14.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p14.cpp
@@ -6,10 +6,26 @@ class NonCopyable {
 
 void capture_by_copy(NonCopyable nc, NonCopyable &ncr) {
   // FIXME: error messages should talk about capture
-  [nc] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}} \
+  (void)[nc] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}} \
              // expected-error{{lambda expressions are not supported yet}}
-  [ncr] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}} \
+  (void)[ncr] { }; // expected-error{{field of type 'NonCopyable' has private copy constructor}} \
              // expected-error{{lambda expressions are not supported yet}}
 }
 
+struct NonTrivial {
+  NonTrivial();
+  NonTrivial(const NonTrivial &);
+  ~NonTrivial();
+};
+
+struct CopyCtorDefault {
+  CopyCtorDefault(const CopyCtorDefault&, NonTrivial nt = NonTrivial());
+
+  void foo() const;
+};
+
+void capture_with_default_args(CopyCtorDefault cct) {
+  (void)[=] () -> void { cct.foo(); }; // expected-error{{lambda expressions are not supported yet}}
+}
+
 // FIXME: arrays!
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p15.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p15.cpp
index 7264fa18d0..e17d8b5101 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p15.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p15.cpp
@@ -5,6 +5,6 @@ class NonCopyable {
 };
 
 void capture_by_ref(NonCopyable nc, NonCopyable &ncr) {
-  [&nc] () -> void {}; // expected-error{{lambda expressions are not supported yet}}
-  [&ncr] () -> void {}; // expected-error{{lambda expressions are not supported yet}}
+  (void)[&nc] () -> void {}; // expected-error{{lambda expressions are not supported yet}}
+  (void)[&ncr] () -> void {}; // expected-error{{lambda expressions are not supported yet}}
 }
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
index a6fca9b2c4..93ba6f61c7 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p5.cpp
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -std=c++11 %s -verify
 
 int test_default_args() {
-  [](int i = 5,  // expected-error{{default arguments can only be specified for parameters in a function declaration}} \
+  (void)[](int i = 5,  // expected-error{{default arguments can only be specified for parameters in a function declaration}} \
                  // expected-error{{lambda expressions are not supported yet}}
      int j = 17) {}; // expected-error{{default arguments can only be specified for parameters in a function declaration}}
 }
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p7.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p7.cpp
index 3c5ac220a1..e816426cbf 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p7.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p7.cpp
@@ -2,7 +2,7 @@
 
 // Check that analysis-based warnings work in lambda bodies.
 void analysis_based_warnings() {
-  []() -> int { }; // expected-warning{{control reaches end of non-void function}} \
+  (void)[]() -> int { }; // expected-warning{{control reaches end of non-void function}} \
   // expected-error{{lambda expressions are not supported yet}}
 }
 
@@ -12,32 +12,32 @@ int &check_const_int(int&);
 float &check_const_int(const int&);
 
 void test_capture_constness(int i, const int ic) {
-  [i,ic] ()->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[i,ic] ()->void { // expected-error{{lambda expressions are not supported yet}}
     float &fr1 = check_const_int(i);
     float &fr2 = check_const_int(ic);
   }; 
 
-  [=] ()->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[=] ()->void { // expected-error{{lambda expressions are not supported yet}}
     float &fr1 = check_const_int(i);
     float &fr2 = check_const_int(ic);
   }; 
 
-  [i,ic] () mutable ->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[i,ic] () mutable ->void { // expected-error{{lambda expressions are not supported yet}}
     int &ir = check_const_int(i);
     float &fr = check_const_int(ic);
   };
 
-  [=] () mutable ->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[=] () mutable ->void { // expected-error{{lambda expressions are not supported yet}}
     int &ir = check_const_int(i);
     float &fr = check_const_int(ic);
   };
 
-  [&i,&ic] ()->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[&i,&ic] ()->void { // expected-error{{lambda expressions are not supported yet}}
     int &ir = check_const_int(i);
     float &fr = check_const_int(ic);
   };
 
-  [&] ()->void { // expected-error{{lambda expressions are not supported yet}}
+  (void)[&] ()->void { // expected-error{{lambda expressions are not supported yet}}
     int &ir = check_const_int(i);
     float &fr = check_const_int(ic);
   };
diff --git a/test/CXX/expr/expr.prim/expr.prim.lambda/p8.cpp b/test/CXX/expr/expr.prim/expr.prim.lambda/p8.cpp
index 4bd5760bc4..53d2c75772 100644
--- a/test/CXX/expr/expr.prim/expr.prim.lambda/p8.cpp
+++ b/test/CXX/expr/expr.prim/expr.prim.lambda/p8.cpp
@@ -4,13 +4,13 @@ class X0 {
   void explicit_capture() {
     int foo;
 
-    [foo, foo] () {}; // expected-error {{'foo' can appear only once}} expected-error {{not supported yet}}
-    [this, this] () {}; // expected-error {{'this' can appear only once}} expected-error {{not supported yet}}
-    [=, foo] () {}; // expected-error {{'&' must precede a capture when}} expected-error {{not supported yet}}
-    [=, &foo] () {}; // expected-error {{not supported yet}}
-    [=, this] () {}; // expected-error {{'this' cannot appear}} expected-error {{not supported yet}}
-    [&, foo] () {}; // expected-error {{not supported yet}}
-    [&, &foo] () {}; // expected-error {{'&' cannot precede a capture when}} expected-error {{not supported yet}}
-    [&, this] () {}; // expected-error {{not supported yet}}
+    (void)[foo, foo] () {}; // expected-error {{'foo' can appear only once}} expected-error {{not supported yet}}
+    (void)[this, this] () {}; // expected-error {{'this' can appear only once}} expected-error {{not supported yet}}
+    (void)[=, foo] () {}; // expected-error {{'&' must precede a capture when}} expected-error {{not supported yet}}
+    (void)[=, &foo] () {}; // expected-error {{not supported yet}}
+    (void)[=, this] () {}; // expected-error {{'this' cannot appear}} expected-error {{not supported yet}}
+    (void)[&, foo] () {}; // expected-error {{not supported yet}}
+    (void)[&, &foo] () {}; // expected-error {{'&' cannot precede a capture when}} expected-error {{not supported yet}}
+    (void)[&, this] () {}; // expected-error {{not supported yet}}
   }
 };
diff --git a/test/SemaCXX/lambda-expressions.cpp b/test/SemaCXX/lambda-expressions.cpp
index 46c74c3c74..a414fc98e7 100644
--- a/test/SemaCXX/lambda-expressions.cpp
+++ b/test/SemaCXX/lambda-expressions.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify -fblocks %s
+// RUN: %clang_cc1 -std=c++0x -Wno-unused-value -fsyntax-only -verify -fblocks %s
 
 namespace std { class type_info; };