Keep track of modules that have failed to build. If we encounter an
import of that module elsewhere, don't try to build the module again:
it won't work, and the experience is quite dreadful. We track this
information somewhat globally, shared among all of the related
CompilerInvocations used to build modules on-the-fly, so that a
particular Clang instance will only try to build a given module once.
Fixes <rdar://problem/12552849>.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@168961 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Modules/epic-fail.m b/test/Modules/epic-fail.m
new file mode 100644
index 0000000..7d2cdcf
--- /dev/null
+++ b/test/Modules/epic-fail.m
@@ -0,0 +1,11 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodule-cache-path %t -fmodules -F %S/Inputs -DgetModuleVersion="epic fail" %s 2>&1 | FileCheck %s
+
+@__experimental_modules_import Module;
+@__experimental_modules_import DependsOnModule;
+
+// CHECK: error: expected ';' after top level declarator
+// CHECK: note: expanded from macro 'getModuleVersion'
+// CHECK: fatal error: could not build module 'Module'
+// CHECK: fatal error: could not build module 'Module'
+// CHECK-NOT: error: