Stop instantiating a class if we hit a static_assert failure. Also, if the

static_assert fails when parsing the template, don't diagnose it again on every
instantiation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160088 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 35 insertions, 17 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index fa42fdd827..ebd9180ec6 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -9736,37 +9736,49 @@ Decl *Sema::ActOnExceptionDeclarator(Scope *S, Declarator &D) {
 
 Decl *Sema::ActOnStaticAssertDeclaration(SourceLocation StaticAssertLoc,
                                          Expr *AssertExpr,
-                                         Expr *AssertMessageExpr_,
+                                         Expr *AssertMessageExpr,
                                          SourceLocation RParenLoc) {
-  StringLiteral *AssertMessage = cast<StringLiteral>(AssertMessageExpr_);
+  StringLiteral *AssertMessage = cast<StringLiteral>(AssertMessageExpr);
 
-  if (!AssertExpr->isTypeDependent() && !AssertExpr->isValueDependent()) {
+  if (DiagnoseUnexpandedParameterPack(AssertExpr, UPPC_StaticAssertExpression))
+    return 0;
+
+  return BuildStaticAssertDeclaration(StaticAssertLoc, AssertExpr,
+                                      AssertMessage, RParenLoc, false);
+}
+
+Decl *Sema::BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
+                                         Expr *AssertExpr,
+                                         StringLiteral *AssertMessage,
+                                         SourceLocation RParenLoc,
+                                         bool Failed) {
+  if (!AssertExpr->isTypeDependent() && !AssertExpr->isValueDependent() &&
+      !Failed) {
     // In a static_assert-declaration, the constant-expression shall be a
     // constant expression that can be contextually converted to bool.
     ExprResult Converted = PerformContextuallyConvertToBool(AssertExpr);
     if (Converted.isInvalid())
-      return 0;
+      Failed = true;
 
     llvm::APSInt Cond;
-    if (VerifyIntegerConstantExpression(Converted.get(), &Cond,
+    if (!Failed && VerifyIntegerConstantExpression(Converted.get(), &Cond,
           diag::err_static_assert_expression_is_not_constant,
           /*AllowFold=*/false).isInvalid())
-      return 0;
+      Failed = true;
 
-    if (!Cond) {
+    if (!Failed && !Cond) {
       llvm::SmallString<256> MsgBuffer;
       llvm::raw_svector_ostream Msg(MsgBuffer);
       AssertMessage->printPretty(Msg, Context, 0, getPrintingPolicy());
       Diag(StaticAssertLoc, diag::err_static_assert_failed)
         << Msg.str() << AssertExpr->getSourceRange();
+      Failed = true;
     }
   }
 
-  if (DiagnoseUnexpandedParameterPack(AssertExpr, UPPC_StaticAssertExpression))
-    return 0;
-
   Decl *Decl = StaticAssertDecl::Create(Context, CurContext, StaticAssertLoc,
-                                        AssertExpr, AssertMessage, RParenLoc);
+                                        AssertExpr, AssertMessage, RParenLoc,
+                                        Failed);
 
   CurContext->addDecl(Decl);
   return Decl;
diff --git a/lib/Sema/SemaTemplateInstantiate.cpp b/lib/Sema/SemaTemplateInstantiate.cpp
index 239a0d73eb..0a0016c50b 100644
--- a/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1904,7 +1904,7 @@ Sema::InstantiateClass(SourceLocation PointOfInstantiation,
       continue;
 
     if ((*Member)->isInvalidDecl()) {
-      Instantiation->setInvalidDecl(); 
+      Instantiation->setInvalidDecl();
       continue;
     }
 
@@ -1928,6 +1928,13 @@ Sema::InstantiateClass(SourceLocation PointOfInstantiation,
           MSInfo->setTemplateSpecializationKind(TSK_ImplicitInstantiation);
           MSInfo->setPointOfInstantiation(PointOfInstantiation);
         }
+      } else if (StaticAssertDecl *SA = dyn_cast<StaticAssertDecl>(NewMember)) {
+        if (SA->isFailed()) {
+          // A static_assert failed. Bail out; instantiating this
+          // class is probably not meaningful.
+          Instantiation->setInvalidDecl();
+          break;
+        }
       }
 
       if (NewMember->isInvalidDecl())
diff --git a/lib/Sema/SemaTemplateInstantiateDecl.cpp b/lib/Sema/SemaTemplateInstantiateDecl.cpp
index cce0b0d093..0d3e8a0ba8 100644
--- a/lib/Sema/SemaTemplateInstantiateDecl.cpp
+++ b/lib/Sema/SemaTemplateInstantiateDecl.cpp
@@ -552,12 +552,11 @@ Decl *TemplateDeclInstantiator::VisitStaticAssertDecl(StaticAssertDecl *D) {
   if (InstantiatedAssertExpr.isInvalid())
     return 0;
 
-  ExprResult Message(D->getMessage());
-  D->getMessage();
-  return SemaRef.ActOnStaticAssertDeclaration(D->getLocation(),
+  return SemaRef.BuildStaticAssertDeclaration(D->getLocation(),
                                               InstantiatedAssertExpr.get(),
-                                              Message.get(),
-                                              D->getRParenLoc());
+                                              D->getMessage(),
+                                              D->getRParenLoc(),
+                                              D->isFailed());
 }
 
 Decl *TemplateDeclInstantiator::VisitEnumDecl(EnumDecl *D) {