Implement cross-module declaration merging for tag declarations, so

that if two modules A and B both contain a declaration of a tag such
as

  struct X;

and those two modules are unrelated, the two declarations of X will be
merged into a single redeclaration chain.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147488 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 59 insertions, 0 deletions

diff --git a/test/Modules/Inputs/redecl-merge-bottom.h b/test/Modules/Inputs/redecl-merge-bottom.h
index a054cd2059..4e52a67247 100644
--- a/test/Modules/Inputs/redecl-merge-bottom.h
+++ b/test/Modules/Inputs/redecl-merge-bottom.h
@@ -13,6 +13,9 @@
 
 @protocol P1;
 
+struct S1;
+struct S3;
+
 void refers_to_C4(C4*);
 
 #ifdef __cplusplus
diff --git a/test/Modules/Inputs/redecl-merge-left.h b/test/Modules/Inputs/redecl-merge-left.h
index 82146f7ed5..b21271b146 100644
--- a/test/Modules/Inputs/redecl-merge-left.h
+++ b/test/Modules/Inputs/redecl-merge-left.h
@@ -15,6 +15,14 @@
 - (void)protoMethod2;
 @end
 
+struct S1;
+struct S2 {
+  int field;
+};
+
+struct S1 *produce_S1(void);
+void consume_S2(struct S2*);
+
 // Test declarations in different modules with no common initial
 // declaration.
 @class C;
@@ -39,6 +47,15 @@ struct explicit_struct;
 
 @protocol P3;
 
+struct S3;
+struct S3;
+struct S4 {
+  int field;
+};
+
+struct S3 *produce_S3(void);
+void consume_S4(struct S4*);
+
 #ifdef __cplusplus
 template<typename T> class Vector;
 
diff --git a/test/Modules/Inputs/redecl-merge-right.h b/test/Modules/Inputs/redecl-merge-right.h
index b6dfe2f53c..686a96228a 100644
--- a/test/Modules/Inputs/redecl-merge-right.h
+++ b/test/Modules/Inputs/redecl-merge-right.h
@@ -21,6 +21,12 @@
 
 @protocol P2;
 
+struct S1;
+struct S2;
+
+void consume_S1(struct S1*);
+struct S2 *produce_S2(void);
+
 // Test declarations in different modules with no common initial
 // declaration.
 @class C;
@@ -47,6 +53,12 @@ struct explicit_struct;
 @protocol P3;
 @protocol P3;
 
+struct S3;
+struct S4;
+
+void consume_S3(struct S3*);
+struct S4 *produce_S4(void);
+
 #ifdef __cplusplus
 template<typename T> class Vector { 
 public:
diff --git a/test/Modules/Inputs/redecl-merge-top.h b/test/Modules/Inputs/redecl-merge-top.h
index 64c0c92546..519254ca22 100644
--- a/test/Modules/Inputs/redecl-merge-top.h
+++ b/test/Modules/Inputs/redecl-merge-top.h
@@ -11,6 +11,10 @@
 @protocol P2;
 @protocol P2;
 
+struct S1;
+struct S2;
+struct S2;
+
 #ifdef __cplusplus
 template<typename T> class Vector;
 #endif
diff --git a/test/Modules/redecl-merge.m b/test/Modules/redecl-merge.m
index dfbc25fe9e..c0e83e8a86 100644
--- a/test/Modules/redecl-merge.m
+++ b/test/Modules/redecl-merge.m
@@ -32,6 +32,29 @@ void testProtoMerge(id<P1> p1, id<P2> p2) {
   [p2 protoMethod2];
 }
 
+struct S1 {
+  int s1_field;
+};
+
+struct S3 {
+  int s3_field;
+};
+
+void testTagMerge() {
+  consume_S1(produce_S1());
+  struct S2 s2;
+  s2.field = 0;
+  consume_S2(produce_S2());
+  struct S1 s1;
+  s1.s1_field = 0;
+  consume_S3(produce_S3());
+  struct S4 s4;
+  s4.field = 0;
+  consume_S4(produce_S4());
+  struct S3 s3;
+  s3.s3_field = 0;
+}
+
 // Test redeclarations of entities in explicit submodules, to make
 // sure we're maintaining the declaration chains even when normal name
 // lookup can't see what we're looking for.