[modules] Don't emit initializers for VarDecls within a module eagerly whenever
we first touch any part of that module. Instead, defer them until the first
time that module is (transitively) imported. The initializer step for a module
then recursively initializes modules that its own headers imported.
For example, this avoids running the <iostream> global initializer in programs
that don't actually use iostreams, but do use other parts of the standard
library.
llvm-svn: 276159
diff --git a/clang/test/Modules/unused-global-init.cpp b/clang/test/Modules/unused-global-init.cpp
new file mode 100644
index 0000000..3bd7a7f
--- /dev/null
+++ b/clang/test/Modules/unused-global-init.cpp
@@ -0,0 +1,37 @@
+// RUN: rm -rf %t
+//
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-module %S/Inputs/unused-global-init/module.modulemap -fmodule-name=init -o %t/init.pcm
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-module %S/Inputs/unused-global-init/module.modulemap -fmodule-name=unused -o %t/unused.pcm -fmodule-file=%t/init.pcm
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-module %S/Inputs/unused-global-init/module.modulemap -fmodule-name=used -o %t/used.pcm -fmodule-file=%t/init.pcm
+//
+// No module file: init.h performs init.
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -DINIT | FileCheck --check-prefix=CHECK-INIT %s
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -DUSED | FileCheck --check-prefix=CHECK-INIT %s
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -DOTHER -DUNUSED | FileCheck --check-prefix=CHECK-NO-INIT %s
+//
+// With module files: if there is a transitive import of any part of the
+// module, we run its global initializers (even if the imported piece is not
+// visible here).
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -fmodule-file=%t/used.pcm -fmodule-file=%t/unused.pcm -DINIT | FileCheck --check-prefix=CHECK-INIT %s
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -fmodule-file=%t/used.pcm -fmodule-file=%t/unused.pcm -DOTHER | FileCheck --check-prefix=CHECK-NO-INIT %s
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -fmodule-file=%t/used.pcm -fmodule-file=%t/unused.pcm -DUSED | FileCheck --check-prefix=CHECK-INIT %s
+// RUN: %clang_cc1 -fmodules -fno-implicit-modules -x c++ -I %S/Inputs/unused-global-init -triple %itanium_abi_triple -emit-llvm -o - %s -fmodule-file=%t/used.pcm -fmodule-file=%t/unused.pcm -DUNUSED | FileCheck --check-prefix=CHECK-NO-INIT %s
+
+#ifdef INIT
+#include "init.h"
+#endif
+
+#ifdef OTHER
+#include "other.h"
+#endif
+
+#ifdef USED
+#include "used.h"
+#endif
+
+#ifdef UNUSED
+#include "unused.h"
+#endif
+
+// CHECK-INIT: call {{.*}}@_ZN4InitC
+// CHECK-NO-INIT-NOT: call {{.*}}@_ZN4InitC