<rdar://problem/13560075> Teach name lookup for builtin names to find hidden declarations.

Normal name lookup ignores any hidden declarations. When name lookup
for builtin declarations fails, we just synthesize a new
declaration at the point of use. With modules, this could lead to
multiple declarations of the same builtin, if one came from a (hidden)
submodule that was later made visible. Teach name lookup to always
find builtin names, so we don't create these redundant declarations in
the first place.

llvm-svn: 178711

4 files changed, 30 insertions, 0 deletions

diff --git a/clang/test/Modules/Inputs/builtin.h b/clang/test/Modules/Inputs/builtin.h
new file mode 100644
index 00000000000..7be90177d19
--- /dev/null
+++ b/clang/test/Modules/Inputs/builtin.h
@@ -0,0 +1,3 @@
+int i;
+int *p = &i;
+
diff --git a/clang/test/Modules/Inputs/builtin_sub.h b/clang/test/Modules/Inputs/builtin_sub.h
new file mode 100644
index 00000000000..79e3c033259
--- /dev/null
+++ b/clang/test/Modules/Inputs/builtin_sub.h
@@ -0,0 +1,4 @@
+int getBos1(void) {
+  return __builtin_object_size(p, 0);
+}
+
diff --git a/clang/test/Modules/Inputs/module.map b/clang/test/Modules/Inputs/module.map
index 93ba4935ffd..595e5d88468 100644
--- a/clang/test/Modules/Inputs/module.map
+++ b/clang/test/Modules/Inputs/module.map
@@ -192,3 +192,10 @@ module config {
 module diag_pragma {
   header "diag_pragma.h"
 }
+
+module builtin {
+  header "builtin.h"
+  explicit module sub {
+    header "builtin_sub.h"
+  }
+}
diff --git a/clang/test/Modules/builtins.m b/clang/test/Modules/builtins.m
new file mode 100644
index 00000000000..40b4f9c7439
--- /dev/null
+++ b/clang/test/Modules/builtins.m
@@ -0,0 +1,16 @@
+@import builtin;
+
+int foo() {
+  return __builtin_object_size(p, 0);
+}
+
+@import builtin.sub;
+
+int bar() {
+  return __builtin_object_size(p, 0);
+}
+
+
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -I %S/Inputs %s -verify
+// expected-no-diagnostics