Don't compute a patched/semantic storage class.

For variables and functions clang used to store two storage classes. The one
"as written" in the code and a patched one, which, for example, propagates
static to the following decls.

This apparently is from the days clang lacked linkage computation. It is now
redundant and this patch removes it.

llvm-svn: 178663

1 files changed, 41 insertions, 55 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index 4b920697629..9505d299ab1 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -498,26 +498,24 @@ static LinkageInfo getLVForNamespaceScopeDecl(const NamedDecl *D,
     //   declared to have external linkage; or (there is no equivalent in C99)
     if (Context.getLangOpts().CPlusPlus &&
         Var->getType().isConstQualified() && 
-        !Var->getType().isVolatileQualified() &&
-        Var->getStorageClass() != SC_Extern &&
-        Var->getStorageClass() != SC_PrivateExtern) {
-      bool FoundExtern = false;
-      for (const VarDecl *PrevVar = Var->getPreviousDecl();
-           PrevVar && !FoundExtern; 
-           PrevVar = PrevVar->getPreviousDecl())
-        if (isExternalLinkage(PrevVar->getLinkage()))
-          FoundExtern = true;
-      
-      if (!FoundExtern)
-        return LinkageInfo::internal();
-    }
-    if (Var->getStorageClass() == SC_None) {
+        !Var->getType().isVolatileQualified()) {
       const VarDecl *PrevVar = Var->getPreviousDecl();
-      for (; PrevVar; PrevVar = PrevVar->getPreviousDecl())
-        if (PrevVar->getStorageClass() == SC_PrivateExtern)
-          break;
       if (PrevVar)
         return PrevVar->getLinkageAndVisibility();
+
+      if (Var->getStorageClass() != SC_Extern &&
+          Var->getStorageClass() != SC_PrivateExtern)
+        return LinkageInfo::internal();
+    }
+
+    for (const VarDecl *PrevVar = Var->getPreviousDecl(); PrevVar;
+         PrevVar = PrevVar->getPreviousDecl()) {
+      if (PrevVar->getStorageClass() == SC_PrivateExtern &&
+          Var->getStorageClass() == SC_None)
+        return PrevVar->getLinkageAndVisibility();
+      // Explicitly declared static.
+      if (PrevVar->getStorageClass() == SC_Static)
+        return LinkageInfo::internal();
     }
   } else if (isa<FunctionDecl>(D) || isa<FunctionTemplateDecl>(D)) {
     // C++ [temp]p4:
@@ -531,7 +529,7 @@ static LinkageInfo getLVForNamespaceScopeDecl(const NamedDecl *D,
       Function = cast<FunctionDecl>(D);
 
     // Explicitly declared static.
-    if (Function->getStorageClass() == SC_Static)
+    if (Function->getCanonicalDecl()->getStorageClass() == SC_Static)
       return LinkageInfo(InternalLinkage, DefaultVisibility, false);
   } else if (const FieldDecl *Field = dyn_cast<FieldDecl>(D)) {
     //   - a data member of an anonymous union.
@@ -995,7 +993,7 @@ static LinkageInfo getLVForLocalDecl(const NamedDecl *D,
       return LinkageInfo::uniqueExternal();
 
     // This is a "void f();" which got merged with a file static.
-    if (Function->getStorageClass() == SC_Static)
+    if (Function->getCanonicalDecl()->getStorageClass() == SC_Static)
       return LinkageInfo::internal();
 
     LinkageInfo LV;
@@ -1013,15 +1011,11 @@ static LinkageInfo getLVForLocalDecl(const NamedDecl *D,
   }
 
   if (const VarDecl *Var = dyn_cast<VarDecl>(D)) {
-    if (Var->hasExternalStorageAsWritten()) {
+    if (Var->hasExternalStorage()) {
       if (Var->isInAnonymousNamespace() &&
           !Var->getDeclContext()->isExternCContext())
         return LinkageInfo::uniqueExternal();
 
-      // This is an "extern int foo;" which got merged with a file static.
-      if (Var->getStorageClass() == SC_Static)
-        return LinkageInfo::internal();
-
       LinkageInfo LV;
       if (Var->getStorageClass() == SC_PrivateExtern)
         LV.mergeVisibility(HiddenVisibility, true);
@@ -1030,9 +1024,13 @@ static LinkageInfo getLVForLocalDecl(const NamedDecl *D,
           LV.mergeVisibility(*Vis, true);
       }
 
-      // Note that Sema::MergeVarDecl already takes care of implementing
-      // C99 6.2.2p4 and propagating the visibility attribute, so we don't
-      // have to do it here.
+      if (const VarDecl *Prev = Var->getPreviousDecl()) {
+        LinkageInfo PrevLV = getLVForDecl(Prev, computation);
+        if (PrevLV.getLinkage())
+          LV.setLinkage(PrevLV.getLinkage());
+        LV.mergeVisibility(PrevLV);
+      }
+
       return LV;
     }
   }
@@ -1467,21 +1465,18 @@ const char *VarDecl::getStorageClassSpecifierString(StorageClass SC) {
 VarDecl *VarDecl::Create(ASTContext &C, DeclContext *DC,
                          SourceLocation StartL, SourceLocation IdL,
                          IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo,
-                         StorageClass S, StorageClass SCAsWritten) {
-  return new (C) VarDecl(Var, DC, StartL, IdL, Id, T, TInfo, S, SCAsWritten);
+                         StorageClass S) {
+  return new (C) VarDecl(Var, DC, StartL, IdL, Id, T, TInfo, S);
 }
 
 VarDecl *VarDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   void *Mem = AllocateDeserializedDecl(C, ID, sizeof(VarDecl));
   return new (Mem) VarDecl(Var, 0, SourceLocation(), SourceLocation(), 0, 
-                           QualType(), 0, SC_None, SC_None);
+                           QualType(), 0, SC_None);
 }
 
 void VarDecl::setStorageClass(StorageClass SC) {
   assert(isLegalForVariable(SC));
-  if (getStorageClass() != SC)
-    assert(isLinkageValid());
-
   VarDeclBits.SClass = SC;
 }
 
@@ -1581,7 +1576,7 @@ VarDecl::DefinitionKind VarDecl::isThisDeclarationADefinition(
   if (hasExternalStorage())
     return DeclarationOnly;
 
-  if (hasExternalStorageAsWritten()) {
+  if (hasExternalStorage()) {
     for (const VarDecl *PrevVar = getPreviousDecl();
          PrevVar; PrevVar = PrevVar->getPreviousDecl()) {
       if (PrevVar->getLinkage() == InternalLinkage)
@@ -1879,16 +1874,15 @@ ParmVarDecl *ParmVarDecl::Create(ASTContext &C, DeclContext *DC,
                                  SourceLocation StartLoc,
                                  SourceLocation IdLoc, IdentifierInfo *Id,
                                  QualType T, TypeSourceInfo *TInfo,
-                                 StorageClass S, StorageClass SCAsWritten,
-                                 Expr *DefArg) {
+                                 StorageClass S, Expr *DefArg) {
   return new (C) ParmVarDecl(ParmVar, DC, StartLoc, IdLoc, Id, T, TInfo,
-                             S, SCAsWritten, DefArg);
+                             S, DefArg);
 }
 
 ParmVarDecl *ParmVarDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   void *Mem = AllocateDeserializedDecl(C, ID, sizeof(ParmVarDecl));
   return new (Mem) ParmVarDecl(ParmVar, 0, SourceLocation(), SourceLocation(),
-                               0, QualType(), 0, SC_None, SC_None, 0);
+                               0, QualType(), 0, SC_None, 0);
 }
 
 SourceRange ParmVarDecl::getSourceRange() const {
@@ -2067,7 +2061,7 @@ bool FunctionDecl::isGlobal() const {
   if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(this))
     return Method->isStatic();
 
-  if (getStorageClass() == SC_Static)
+  if (getCanonicalDecl()->getStorageClass() == SC_Static)
     return false;
 
   for (const DeclContext *DC = getDeclContext();
@@ -2112,14 +2106,6 @@ FunctionDecl *FunctionDecl::getCanonicalDecl() {
   return getFirstDeclaration();
 }
 
-void FunctionDecl::setStorageClass(StorageClass SC) {
-  assert(isLegalForFunction(SC));
-  if (getStorageClass() != SC)
-    assert(isLinkageValid());
-
-  SClass = SC;
-}
-
 /// \brief Returns a value indicating whether this function
 /// corresponds to a builtin function.
 ///
@@ -2270,7 +2256,7 @@ bool FunctionDecl::doesDeclarationForceExternallyVisibleDefinition() const {
     //
     // FIXME: What happens if gnu_inline gets added on after the first
     // declaration?
-    if (!isInlineSpecified() || getStorageClassAsWritten() == SC_Extern)
+    if (!isInlineSpecified() || getStorageClass() == SC_Extern)
       return false;
 
     const FunctionDecl *Prev = this;
@@ -2282,10 +2268,10 @@ bool FunctionDecl::doesDeclarationForceExternallyVisibleDefinition() const {
         // If it's not the case that both 'inline' and 'extern' are
         // specified on the definition, then it is always externally visible.
         if (!Prev->isInlineSpecified() ||
-            Prev->getStorageClassAsWritten() != SC_Extern)
+            Prev->getStorageClass() != SC_Extern)
           return false;
       } else if (Prev->isInlineSpecified() && 
-                 Prev->getStorageClassAsWritten() != SC_Extern) {
+                 Prev->getStorageClass() != SC_Extern) {
         return false;
       }
     }
@@ -2340,7 +2326,7 @@ bool FunctionDecl::isInlineDefinitionExternallyVisible() const {
     // If it's not the case that both 'inline' and 'extern' are
     // specified on the definition, then this inline definition is
     // externally visible.
-    if (!(isInlineSpecified() && getStorageClassAsWritten() == SC_Extern))
+    if (!(isInlineSpecified() && getStorageClass() == SC_Extern))
       return true;
     
     // If any declaration is 'inline' but not 'extern', then this definition
@@ -2349,7 +2335,7 @@ bool FunctionDecl::isInlineDefinitionExternallyVisible() const {
          Redecl != RedeclEnd;
          ++Redecl) {
       if (Redecl->isInlineSpecified() && 
-          Redecl->getStorageClassAsWritten() != SC_Extern)
+          Redecl->getStorageClass() != SC_Extern)
         return true;
     }    
     
@@ -3212,12 +3198,12 @@ FunctionDecl *FunctionDecl::Create(ASTContext &C, DeclContext *DC,
                                    SourceLocation StartLoc,
                                    const DeclarationNameInfo &NameInfo,
                                    QualType T, TypeSourceInfo *TInfo,
-                                   StorageClass SC, StorageClass SCAsWritten,
+                                   StorageClass SC,
                                    bool isInlineSpecified, 
                                    bool hasWrittenPrototype,
                                    bool isConstexprSpecified) {
   FunctionDecl *New = new (C) FunctionDecl(Function, DC, StartLoc, NameInfo,
-                                           T, TInfo, SC, SCAsWritten,
+                                           T, TInfo, SC,
                                            isInlineSpecified,
                                            isConstexprSpecified);
   New->HasWrittenPrototype = hasWrittenPrototype;
@@ -3228,7 +3214,7 @@ FunctionDecl *FunctionDecl::CreateDeserialized(ASTContext &C, unsigned ID) {
   void *Mem = AllocateDeserializedDecl(C, ID, sizeof(FunctionDecl));
   return new (Mem) FunctionDecl(Function, 0, SourceLocation(), 
                                 DeclarationNameInfo(), QualType(), 0,
-                                SC_None, SC_None, false, false);
+                                SC_None, false, false);
 }
 
 BlockDecl *BlockDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L) {