Many refinements to Sema::MergeVarDecl(). This routine still needs some re-work to fully handle tentative decls.

This includes a fix to bz1908.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@46540 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 42 insertions, 12 deletions

diff --git a/Sema/SemaDecl.cpp b/Sema/SemaDecl.cpp
index 9dd306944d..68177e03c8 100644
--- a/Sema/SemaDecl.cpp
+++ b/Sema/SemaDecl.cpp
@@ -319,26 +319,56 @@ VarDecl *Sema::MergeVarDecl(VarDecl *New, ScopedDecl *OldD) {
     Diag(OldD->getLocation(), diag::err_previous_definition);
     return New;
   }
+  // Verify the types match.
+  if (Old->getCanonicalType() != New->getCanonicalType() && 
+      !areEquivalentArrayTypes(New->getCanonicalType(), Old->getCanonicalType())) {
+    Diag(New->getLocation(), diag::err_redefinition, New->getName());
+    Diag(Old->getLocation(), diag::err_previous_definition);
+    return New;
+  }
+  // C99 6.2.2p4: Check if we have a static decl followed by a non-static.
+  if (New->getStorageClass() == VarDecl::Static &&
+      (Old->getStorageClass() == VarDecl::None ||
+       Old->getStorageClass() == VarDecl::Extern)) {
+    Diag(New->getLocation(), diag::err_static_non_static, New->getName());
+    Diag(Old->getLocation(), diag::err_previous_definition);
+    return New;
+  }
+  // C99 6.2.2p4: Check if we have a non-static decl followed by a static.
+  if (New->getStorageClass() != VarDecl::Static &&
+      Old->getStorageClass() == VarDecl::Static) {
+    Diag(New->getLocation(), diag::err_non_static_static, New->getName());
+    Diag(Old->getLocation(), diag::err_previous_definition);
+    return New;
+  }
+  // We've verified the types match, now handle "tentative" definitions.
   FileVarDecl *OldFSDecl = dyn_cast<FileVarDecl>(Old);
   FileVarDecl *NewFSDecl = dyn_cast<FileVarDecl>(New);
-  bool OldIsTentative = false;
   
-  if (OldFSDecl && NewFSDecl) { // C99 6.9.2
-    // Handle C "tentative" external object definitions. FIXME: finish!
+  if (OldFSDecl && NewFSDecl) {
+    // Handle C "tentative" external object definitions (C99 6.9.2).
+    bool OldIsTentative = false;
+    bool NewIsTentative = false;
+    
     if (!OldFSDecl->getInit() &&
         (OldFSDecl->getStorageClass() == VarDecl::None ||
          OldFSDecl->getStorageClass() == VarDecl::Static))
       OldIsTentative = true;
+      
+    // FIXME: this check doesn't work (since the initializer hasn't been
+    // attached yet). This check should be moved to FinalizeDeclaratorGroup.
+    // Unfortunately, by the time we get to FinializeDeclaratorGroup, we've 
+    // thrown out the old decl.
+    if (!NewFSDecl->getInit() &&
+        (NewFSDecl->getStorageClass() == VarDecl::None ||
+         NewFSDecl->getStorageClass() == VarDecl::Static))
+      ; // change to NewIsTentative = true; once the code is moved.
+    
+    if (NewIsTentative || OldIsTentative)
+      return New;
   }
-  // Verify the types match.
-  if (Old->getCanonicalType() != New->getCanonicalType() && 
-      !areEquivalentArrayTypes(New->getCanonicalType(), Old->getCanonicalType())) {
-    Diag(New->getLocation(), diag::err_redefinition, New->getName());
-    Diag(Old->getLocation(), diag::err_previous_definition);
-    return New;
-  }
-  // We've verified the types match, now check if Old is "extern".
-  if (Old->getStorageClass() != VarDecl::Extern) {
+  if (Old->getStorageClass() != VarDecl::Extern &&
+      New->getStorageClass() != VarDecl::Extern) {
     Diag(New->getLocation(), diag::err_redefinition, New->getName());
     Diag(Old->getLocation(), diag::err_previous_definition);
   }