Fix an old (2009) FIXME:

// FIXME: This needs to happen before we merge declarations. Then,
// let attribute merging cope with attribute conflicts.

This was already being done for variables, but for functions we were merging
then first and then applying the attributes. To avoid duplicating merging
logic, some of the helpers in SemaDeclAttr.cpp become methods that can
handle merging two attributes in one decl or inheriting attributes from one
decl to another.

With this change we are now able to produce errors for variables with
incompatible visibility attributes or warn about unused dllimports in
variables.

This changes the attribute list iteration back to being in reverse source
code order, as that matches what decl merging does and avoids differentiating
the two cases is the merge*Attr methods.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@156531 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 40 insertions, 24 deletions

diff --git a/lib/Sema/TargetAttributesSema.cpp b/lib/Sema/TargetAttributesSema.cpp
index c0746388e5..9ace9ad65a 100644
--- a/lib/Sema/TargetAttributesSema.cpp
+++ b/lib/Sema/TargetAttributesSema.cpp
@@ -151,6 +151,24 @@ static void HandleX86ForceAlignArgPointerAttr(Decl *D,
                                                            S.Context));
 }
 
+bool Sema::mergeDLLImportAttr(Decl *D, SourceRange Range, bool Inherited) {
+  if (D->hasAttr<DLLExportAttr>()) {
+    Diag(Range.getBegin(), diag::warn_attribute_ignored) << "dllimport";
+    return false;
+  }
+
+  if (D->hasAttr<DLLImportAttr>())
+    return false;
+
+  DLLImportAttr *Attr =
+    ::new (Context) DLLImportAttr(Range, Context);
+  if (Inherited)
+    Attr->setInherited(true);
+  D->addAttr(Attr);
+
+  return true;
+}
+
 static void HandleDLLImportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
   // check the attribute arguments.
   if (Attr.getNumArgs() != 0) {
@@ -159,13 +177,8 @@ static void HandleDLLImportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
   }
 
   // Attribute can be applied only to functions or variables.
-  if (isa<VarDecl>(D)) {
-    D->addAttr(::new (S.Context) DLLImportAttr(Attr.getLoc(), S.Context));
-    return;
-  }
-
   FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
-  if (!FD) {
+  if (!FD && !isa<VarDecl>(D)) {
     // Apparently Visual C++ thinks it is okay to not emit a warning
     // in this case, so only emit a warning when -fms-extensions is not
     // specified.
@@ -177,17 +190,30 @@ static void HandleDLLImportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
 
   // Currently, the dllimport attribute is ignored for inlined functions.
   // Warning is emitted.
-  if (FD->isInlineSpecified()) {
+  if (FD && FD->isInlineSpecified()) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "dllimport";
     return;
   }
 
-  if (D->getAttr<DLLExportAttr>()) {
-    S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "dllimport";
-    return;
+  S.mergeDLLImportAttr(D, Attr.getRange(), false);
+}
+
+bool Sema::mergeDLLExportAttr(Decl *D, SourceRange Range, bool Inherited) {
+  if (DLLImportAttr *Import = D->getAttr<DLLImportAttr>()) {
+    Diag(Import->getLocation(), diag::warn_attribute_ignored) << "dllimport";
+    D->dropAttr<DLLImportAttr>();
   }
 
-  D->addAttr(::new (S.Context) DLLImportAttr(Attr.getLoc(), S.Context));
+  if (D->hasAttr<DLLExportAttr>())
+    return false;
+
+  DLLExportAttr *Attr =
+    ::new (Context) DLLExportAttr(Range, Context);
+  if (Inherited)
+    Attr->setInherited(true);
+  D->addAttr(Attr);
+
+  return true;
 }
 
 static void HandleDLLExportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
@@ -198,13 +224,8 @@ static void HandleDLLExportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
   }
 
   // Attribute can be applied only to functions or variables.
-  if (isa<VarDecl>(D)) {
-    D->addAttr(::new (S.Context) DLLExportAttr(Attr.getLoc(), S.Context));
-    return;
-  }
-
   FunctionDecl *FD = dyn_cast<FunctionDecl>(D);
-  if (!FD) {
+  if (!FD && !isa<VarDecl>(D)) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
       << Attr.getName() << 2 /*variable and function*/;
     return;
@@ -212,18 +233,13 @@ static void HandleDLLExportAttr(Decl *D, const AttributeList &Attr, Sema &S) {
 
   // Currently, the dllexport attribute is ignored for inlined functions, unless
   // the -fkeep-inline-functions flag has been used. Warning is emitted;
-  if (FD->isInlineSpecified()) {
+  if (FD && FD->isInlineSpecified()) {
     // FIXME: ... unless the -fkeep-inline-functions flag has been used.
     S.Diag(Attr.getLoc(), diag::warn_attribute_ignored) << "dllexport";
     return;
   }
 
-  if (DLLImportAttr *Import = D->getAttr<DLLImportAttr>()) {
-    S.Diag(Import->getLocation(), diag::warn_attribute_ignored) << "dllimport";
-    D->dropAttr<DLLImportAttr>();
-  }
-
-  D->addAttr(::new (S.Context) DLLExportAttr(Attr.getLoc(), S.Context));
+  S.mergeDLLExportAttr(D, Attr.getRange(), false);
 }
 
 namespace {