Add llvm-style RTTI to ObjectFile hierarchy

Summary:
On the heels of D62934, this patch uses the same approach to introduce
llvm RTTI support to the ObjectFile hierarchy. It also replaces the
existing uses of GetPluginName doing run-time type checks with
llvm::dyn_cast and friends.

This formally introduces new dependencies from some other plugins to
ObjectFile plugins. However, I believe this is fine because:
- these dependencies were already kind of there, and the only reason
  we could get away with not modeling them explicitly was because the
  code was relying on magically knowing what will GetPluginName() return
  for a particular kind of object files.
- the dependencies themselves are logical (it makes sense for
  SymbolVendorELF to depend on ObjectFileELF), or at least don't
  actively get in the way (the JitLoaderGDB->MachO thing).
- they don't introduce any new dependency loops as ObjectFile plugins
  don't depend on any other plugins

Reviewers: xiaobai, JDevlieghere, espindola

Subscribers: emaste, mgorny, arichardson, MaskRay, lldb-commits

Differential Revision: https://reviews.llvm.org/D65450

llvm-svn: 367413

1 files changed, 7 insertions, 0 deletions

diff --git a/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.h b/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.h
index 99241126cd1..c992683cfc3 100644
--- a/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.h
+++ b/lldb/source/Plugins/ObjectFile/JIT/ObjectFileJIT.h
@@ -46,6 +46,13 @@ public:
                                         lldb::offset_t length,
                                         lldb_private::ModuleSpecList &specs);
 
+  // LLVM RTTI support
+  static char ID;
+  bool isA(const void *ClassID) const override {
+    return ClassID == &ID || ObjectFile::isA(ClassID);
+  }
+  static bool classof(const ObjectFile *obj) { return obj->isA(&ID); }
+
   // Member Functions
   bool ParseHeader() override;