Currently LLDB calls into ide::getDeclFromMangledSymbolName() to get
to this information and we would like to get rid of this call.
rdar://problem/47798056
instead of using name and decl context.
The advantages of this approach are three-fold:
- This is necessary to support inlined generic functions.
- We can retire the debugger-specific type name manfgling mode for archetypes.
- This saves 270kb of debug information in the x86_64 libSwiftCore.dylib alone.
<rdar://problem/38306256>
It hass been a longstanding principle in LLVM that the presence of
debug info shall not affect code generation. This patch brings the
Swift frontend closer to this ideal:
- unconditionally emit shadow copies
- unconditionally bind type metadata
The extra allocas, bitcasts, geps, and stores being emitted get
optimized away when compiling at anything but -Onone. There are few
use-cases for compiling at -Onone without -g, so this shouldn't affect
performance for any real-world use-cases.
