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

1 files changed, 77 insertions, 0 deletions

diff --git a/clang/test/Modules/macros2.c b/clang/test/Modules/macros2.c
new file mode 100644
index 00000000000..87b4c97d96d
--- /dev/null
+++ b/clang/test/Modules/macros2.c
@@ -0,0 +1,77 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules -x objective-c -emit-module -fmodules-cache-path=%t -fmodule-name=macros_top %S/Inputs/module.map
+// RUN: %clang_cc1 -fmodules -x objective-c -emit-module -fmodules-cache-path=%t -fmodule-name=macros_left %S/Inputs/module.map
+// RUN: %clang_cc1 -fmodules -x objective-c -emit-module -fmodules-cache-path=%t -fmodule-name=macros_right %S/Inputs/module.map
+// RUN: %clang_cc1 -fmodules -x objective-c -emit-module -fmodules-cache-path=%t -fmodule-name=macros %S/Inputs/module.map
+// RUN: %clang_cc1 -fmodules -x objective-c -verify -fmodules-cache-path=%t -I %S/Inputs %s
+
+// This test checks some of the same things as macros.c, but imports modules in
+// a different order.
+
+@import macros_other;
+
+int n0 = TOP_OTHER_DEF_RIGHT_UNDEF; // ok
+
+@import macros_top;
+
+TOP_OTHER_DEF_RIGHT_UNDEF *n0b; // expected-warning{{ambiguous expansion of macro 'TOP_OTHER_DEF_RIGHT_UNDEF'}}
+// expected-note@macros_top.h:22 {{expanding this definition of 'TOP_OTHER_DEF_RIGHT_UNDEF'}}
+// expected-note@macros_other.h:6 {{other definition of 'TOP_OTHER_DEF_RIGHT_UNDEF'}}
+
+@import macros_right;
+@import macros_left;
+
+#ifdef TOP_LEFT_UNDEF
+#  error TOP_LEFT_UNDEF should not be defined
+#endif
+
+#ifndef TOP_RIGHT_UNDEF
+#  error TOP_RIGHT_UNDEF should still be defined
+#endif
+
+void test() {
+  float f;
+  TOP_RIGHT_REDEF *fp = &f; // ok, right's definition overrides top's definition
+
+  // Note, left's definition wins here, whereas right's definition wins in
+  // macros.c.
+  int i;
+  LEFT_RIGHT_IDENTICAL *ip = &i;
+  LEFT_RIGHT_DIFFERENT *ip2 = &f; // expected-warning{{ambiguous expansion of macro 'LEFT_RIGHT_DIFFERENT'}}
+  // expected-note@macros_left.h:14 {{expanding this}}
+  // expected-note@macros_right.h:12 {{other}}
+  LEFT_RIGHT_DIFFERENT2 *ip3 = &f; // expected-warning{{ambiguous expansion of macro 'LEFT_RIGHT_DIFFERENT2}}
+  // expected-note@macros_left.h:11 {{expanding this}}
+  // expected-note@macros_right.h:13 {{other}}
+#undef LEFT_RIGHT_DIFFERENT3
+  int LEFT_RIGHT_DIFFERENT3;
+}
+
+@import macros_right.undef;
+
+// FIXME: See macros.c.
+#ifdef TOP_RIGHT_UNDEF
+# error TOP_RIGHT_UNDEF should not be defined
+#endif
+
+#ifndef TOP_OTHER_UNDEF1
+# error TOP_OTHER_UNDEF1 should still be defined
+#endif
+
+#ifndef TOP_OTHER_UNDEF2
+# error TOP_OTHER_UNDEF2 should still be defined
+#endif
+
+#ifndef TOP_OTHER_REDEF1
+# error TOP_OTHER_REDEF1 should still be defined
+#endif
+int n1 = TOP_OTHER_REDEF1; // expected-warning{{ambiguous expansion of macro 'TOP_OTHER_REDEF1'}}
+// expected-note@macros_top.h:19 {{expanding this definition}}
+// expected-note@macros_other.h:4 {{other definition}}
+
+#ifndef TOP_OTHER_REDEF2
+# error TOP_OTHER_REDEF2 should still be defined
+#endif
+int n2 = TOP_OTHER_REDEF2; // ok
+
+int n3 = TOP_OTHER_DEF_RIGHT_UNDEF; // ok