[modules] Teach the ASTWriter to ignore mutations coming from the ASTReader.
Processing update records (and loading a module, in general) might trigger
unexpected calls to the ASTWriter (being a mutation listener). Now we have a
mechanism to suppress those calls to the ASTWriter but notify other possible
mutation listeners.
Fixes https://llvm.org/bugs/show_bug.cgi?id=28332
Patch by Cristina Cristescu and me.
Reviewed by Richard Smith (D21800).
llvm-svn: 276473
diff --git a/clang/test/Modules/Inputs/PR28332/module.modulemap b/clang/test/Modules/Inputs/PR28332/module.modulemap
new file mode 100644
index 0000000..8c3f4ec
--- /dev/null
+++ b/clang/test/Modules/Inputs/PR28332/module.modulemap
@@ -0,0 +1,3 @@
+module "c.h" { header "c.h" export * }
+module "b.h" { header "b.h" export * }
+module "a.h" { header "a.h" }