Make Sema::LocallyScopedExternalDecls lazily deserialized. In theory,

we could turn this into an on-disk hash table so we don't load the
whole thing the first time we need it. However, it tends to be very,
very small (i.e., empty) for most precompiled headers, so it isn't all
that interesting.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@136352 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 20 insertions, 3 deletions

diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index cb82b0c489..321ab780d4 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -3330,6 +3330,23 @@ Sema::RegisterLocallyScopedExternCDecl(NamedDecl *ND,
   }
 }
 
+llvm::DenseMap<DeclarationName, NamedDecl *>::iterator
+Sema::findLocallyScopedExternalDecl(DeclarationName Name) {
+  if (ExternalSource) {
+    // Load locally-scoped external decls from the external source.
+    SmallVector<NamedDecl *, 4> Decls;
+    ExternalSource->ReadLocallyScopedExternalDecls(Decls);
+    for (unsigned I = 0, N = Decls.size(); I != N; ++I) {
+      llvm::DenseMap<DeclarationName, NamedDecl *>::iterator Pos
+        = LocallyScopedExternalDecls.find(Decls[I]->getDeclName());
+      if (Pos == LocallyScopedExternalDecls.end())
+        LocallyScopedExternalDecls[Decls[I]->getDeclName()] = Decls[I];
+    }
+  }
+  
+  return LocallyScopedExternalDecls.find(Name);
+}
+
 /// \brief Diagnose function specifiers on a declaration of an identifier that
 /// does not identify a function.
 void Sema::DiagnoseFunctionSpecifiers(Declarator& D) {
@@ -4008,7 +4025,7 @@ void Sema::CheckVariableDeclaration(VarDecl *NewVD,
     // an extern "C" variable, look for a non-visible extern "C"
     // declaration with the same name.
     llvm::DenseMap<DeclarationName, NamedDecl *>::iterator Pos
-      = LocallyScopedExternalDecls.find(NewVD->getDeclName());
+      = findLocallyScopedExternalDecl(NewVD->getDeclName());
     if (Pos != LocallyScopedExternalDecls.end())
       Previous.addDecl(Pos->second);
   }
@@ -4970,7 +4987,7 @@ void Sema::CheckFunctionDeclaration(Scope *S, FunctionDecl *NewFD,
     // an extern "C" function, look for a non-visible extern "C"
     // declaration with the same name.
     llvm::DenseMap<DeclarationName, NamedDecl *>::iterator Pos
-      = LocallyScopedExternalDecls.find(NewFD->getDeclName());
+      = findLocallyScopedExternalDecl(NewFD->getDeclName());
     if (Pos != LocallyScopedExternalDecls.end())
       Previous.addDecl(Pos->second);
   }
@@ -6584,7 +6601,7 @@ NamedDecl *Sema::ImplicitlyDefineFunction(SourceLocation Loc,
   // this name as a function or variable. If so, use that
   // (non-visible) declaration, and complain about it.
   llvm::DenseMap<DeclarationName, NamedDecl *>::iterator Pos
-    = LocallyScopedExternalDecls.find(&II);
+    = findLocallyScopedExternalDecl(&II);
   if (Pos != LocallyScopedExternalDecls.end()) {
     Diag(Loc, diag::warn_use_out_of_scope_declaration) << Pos->second;
     Diag(Pos->second->getLocation(), diag::note_previous_declaration);