If a module A exports a macro M, and a module B imports that macro and #undef's
it, importers of B should not see the macro. This is complicated by the fact
that A's macro could also be visible through a different path. The rules (as
hashed out on cfe-commits) are included as a documentation update in this
change.
With this, the number of regressions in libc++'s testsuite when modules are
enabled drops from 47 to 7. Those remaining 7 are also macro-related, and are
due to remaining bugs in this change (in particular, the handling of submodules
is imperfect).
llvm-svn: 202560
diff --git a/clang/test/PCH/macro-undef.cpp b/clang/test/PCH/macro-undef.cpp
new file mode 100644
index 0000000..c0ce2de
--- /dev/null
+++ b/clang/test/PCH/macro-undef.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -emit-pch -o %t %s
+// RUN: %clang_cc1 -fsyntax-only -include-pch %t %s -Wuninitialized -verify
+// RUN: %clang_cc1 -fsyntax-only -include-pch %t %s -Wuninitialized -fdiagnostics-parseable-fixits 2>&1 | FileCheck %s
+
+#ifndef HEADER
+#define HEADER
+
+#define NULL 0
+template<typename T>
+void *f() {
+ void *p; // @11
+ return p; // @12
+}
+#undef NULL
+template<typename T>
+void *g() {
+ void *p; // @17
+ return p; // @18
+}
+
+#else
+
+// expected-warning@12 {{uninitialized}}
+// expected-note@11 {{initialize}}
+// CHECK: fix-it:"{{.*}}":{11:10-11:10}:" = NULL"
+
+// expected-warning@18 {{uninitialized}}
+// expected-note@17 {{initialize}}
+// CHECK: fix-it:"{{.*}}":{17:10-17:10}:" = 0"
+
+int main() {
+ f<int>(); // expected-note {{instantiation}}
+ g<int>(); // expected-note {{instantiation}}
+}
+
+#endif