Serialize the AST reader's mapping from canonical declarations to the

set of (previously-canonical) declaration IDs to the module file, so
that future AST reader instances that load the module know which
declarations are merged. This is important in the fairly tricky case
where a declaration of an entity, e.g.,

  @class X;

occurs before the import of a module that also declares that
entity. We merge the declarations, and record the fact that the
declaration of X loaded from the module was merged into the (now
canonical) declaration of X that we parsed.

llvm-svn: 147181

3 files changed, 10 insertions, 1 deletions

diff --git a/clang/test/Modules/Inputs/redecl-merge-bottom.h b/clang/test/Modules/Inputs/redecl-merge-bottom.h
index ce4368d08a0..50c191c8b60 100644
--- a/clang/test/Modules/Inputs/redecl-merge-bottom.h
+++ b/clang/test/Modules/Inputs/redecl-merge-bottom.h
@@ -8,6 +8,8 @@ __import_module__ redecl_merge_right;
 
 @class A;
 
+void refers_to_C4(C4*);
+
 #ifdef __cplusplus
 template<typename T> class Vector;
 
diff --git a/clang/test/Modules/Inputs/redecl-merge-left.h b/clang/test/Modules/Inputs/redecl-merge-left.h
index 7f355e8f9d6..c4789ad0c03 100644
--- a/clang/test/Modules/Inputs/redecl-merge-left.h
+++ b/clang/test/Modules/Inputs/redecl-merge-left.h
@@ -22,6 +22,8 @@ void accept_a_C2(C2*);
 void accept_a_C3(C3*);
 @class C3;
 
+@class C4;
+
 @class Explicit;
 
 int *explicit_func(void);
diff --git a/clang/test/Modules/redecl-merge.m b/clang/test/Modules/redecl-merge.m
index 930e8df6b87..ea04037707e 100644
--- a/clang/test/Modules/redecl-merge.m
+++ b/clang/test/Modules/redecl-merge.m
@@ -58,13 +58,18 @@ void test_C3(C3 *c3) {
 C4 *global_C4;
 __import_module__ redecl_merge_left_left;
 
-void test_C4(C4 *c4) {
+void test_C4a(C4 *c4) {
   global_C4 = c4 = get_a_C4();
   accept_a_C4(c4);
 }
 
 __import_module__ redecl_merge_bottom;
 
+void test_C4b() {
+  if (&refers_to_C4) {
+  }
+}
+
 @implementation B
 + (B*)create_a_B { return 0; }
 @end