[PCH] Fix a PCH serialization crash, with invalid code related to forward enum references.

The problem was that an enum without closing semicolon could be associated as a forward enum
in an erroneous declaration, leading to the identifier being associated with the enum decl but
without a declaration actually referencing it.
This resulted in not having it serialized before serializing the identifier that is associated with.

Also prevent the ASTUnit from querying the serialized DeclID for an invalid top-level decl; it may not
have been serialized.

rdar://14539667

llvm-svn: 187914

clang/lib/Frontend/ASTUnit.cpp

@@ -1030,9 +1030,13 @@ public:
       // parsing into declaration IDs in the precompiled
       // preamble. This will allow us to deserialize those top-level
       // declarations when requested.
-      for (unsigned I = 0, N = TopLevelDecls.size(); I != N; ++I)
-        Unit.addTopLevelDeclFromPreamble(
-                                      getWriter().getDeclID(TopLevelDecls[I]));
+      for (unsigned I = 0, N = TopLevelDecls.size(); I != N; ++I) {
+        Decl *D = TopLevelDecls[I];
+        // Invalid top-level decls may not have been serialized.
+        if (D->isInvalidDecl())
+          continue;
+        Unit.addTopLevelDeclFromPreamble(getWriter().getDeclID(D));
+      }
 
       Action->setHasEmittedPreamblePCH();
     }

clang/lib/Serialization/ASTWriter.cpp

@@ -4047,6 +4047,21 @@ void ASTWriter::WriteASTCore(Sema &SemaRef,
     GetDeclRef(*I);
   }
 
+  // Make sure all decls associated with an identifier are registered for
+  // serialization.
+  for (IdentifierTable::iterator ID = PP.getIdentifierTable().begin(),
+                              IDEnd = PP.getIdentifierTable().end();
+       ID != IDEnd; ++ID) {
+    const IdentifierInfo *II = ID->second;
+    if (!Chain || !II->isFromAST() || II->hasChangedSinceDeserialization()) {
+      for (IdentifierResolver::iterator D = SemaRef.IdResolver.begin(II),
+                                     DEnd = SemaRef.IdResolver.end();
+           D != DEnd; ++D) {
+        GetDeclRef(*D);
+      }
+    }
+  }
+
   // Resolve any declaration pointers within the declaration updates block.
   ResolveDeclUpdatesBlocks();
   

clang/test/Index/Inputs/preamble-with-error.h

@@ -0,0 +1,3 @@
+typedef int Int;
+enum FFF
+extern Int *const www;

clang/test/Index/pch-with-errors.m

@@ -9,6 +9,12 @@
 -(void)meth;
 @end
 
+struct FFF1
+extern I2 *somevar1;
+
+enum FFF2
+extern I2 *somevar2;
+
 #else
 
 void foo(I2 *i) {

clang/test/Index/preamble.c

@@ -1,5 +1,7 @@
 #include "prefix.h"
 #include "preamble.h"
+#include "preamble-with-error.h"
+
 int wibble(int);
 
 void f(int x) {
@@ -14,10 +16,10 @@ void f(int x) {
 // CHECK: preamble.h:4:9: UnexposedExpr=ptr1:3:10 Extent=[4:9 - 4:13]
 // CHECK: preamble.h:4:9: DeclRefExpr=ptr1:3:10 Extent=[4:9 - 4:13]
 // CHECK: preamble.h:5:10: IntegerLiteral= Extent=[5:10 - 5:11]
-// CHECK: preamble.c:3:5: FunctionDecl=wibble:3:5 Extent=[3:1 - 3:16]
-// CHECK: preamble.c:3:15: ParmDecl=:3:15 (Definition) Extent=[3:12 - 3:16]
+// CHECK: preamble.c:5:5: FunctionDecl=wibble:5:5 Extent=[5:1 - 5:16]
+// CHECK: preamble.c:5:15: ParmDecl=:5:15 (Definition) Extent=[5:12 - 5:16]
 // CHECK-DIAG: preamble.h:4:7:{4:9-4:13}: warning: incompatible pointer types assigning to 'int *' from 'float *'
-// RUN: env CINDEXTEST_EDITING=1 c-index-test -code-completion-at=%s:6:1 -I %S/Inputs -include %t %s 2> %t.stderr.txt | FileCheck -check-prefix CHECK-CC %s
+// RUN: env CINDEXTEST_EDITING=1 c-index-test -code-completion-at=%s:8:1 -I %S/Inputs -include %t %s 2> %t.stderr.txt | FileCheck -check-prefix CHECK-CC %s
 // CHECK-CC: FunctionDecl:{ResultType int}{TypedText bar}{LeftParen (}{Placeholder int i}{RightParen )} (50)
 // CHECK-CC: FunctionDecl:{ResultType void}{TypedText f}{LeftParen (}{Placeholder int x}{RightParen )} (50)
 // CHECK-CC: FunctionDecl:{ResultType int}{TypedText foo}{LeftParen (}{Placeholder int}{RightParen )} (50)