[PCH] Avoid VarDecl emission attempt if no owning module avaiable

This is a stopgap fix for PR31863, a regression introduced in r276159.

Consider this snippet:

struct FVector;
struct FVector {};
struct FBox {
  FVector Min;
  FBox(int);
};
namespace {
FBox InvalidBoundingBox(0);
}

While parsing the DECL_VAR for 'struct FBox', clang recursively read all the
dep decls until it finds the DECL_CXX_RECORD forward declaration for 'struct
FVector'. Then, it resumes all the way up back to DECL_VAR handling in
`ReadDeclRecord`, where it checks if `isConsumerInterestedIn` for the decl.

One of the condition for `isConsumerInterestedIn` to return false is if the
VarDecl is imported from a module `D->getImportedOwningModule()`, because it
will get emitted when we import the relevant module. However, before checking
if it comes from a module, clang checks if `Ctx.DeclMustBeEmitted(D)`, which
triggers the emission of 'struct FBox'. Since one of its fields is still
incomplete, it crashes.

Instead, check if `D->getImportedOwningModule()` is true before calling
`Ctx.DeclMustBeEmitted(D)`.

Differential Revision: https://reviews.llvm.org/D29753

rdar://problem/30173654

llvm-svn: 296656

0 files changed, 0 insertions, 0 deletions