IRGen: Add another lldb resilience hack [4.2] #17726
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When accessing global variables defined in the REPL, lldb does not consult debug info, so it does not see that the DW_OP_deref was emitted. So instead, set a special bit on globals defined in the REPL which bypasses resilience for them altogether. Part of the fix <rdar://problem/39722386>.
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@swift-ci Please test |
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Description: Global variables with a resiliently-sized type cannot have statically-allocated storage, because their size is not known at compile time. Instead, IRGen dynamically allocates space, using a small buffer optimization if the runtime size of the global is less than three words. lldb is currently not smart enough to figure this out. We added a workaround for globals defined in compiled code, but REPL globals do not consult DWARF debug info so another workaround is needed. Add a global bit to VarDecl which gets set by LLDB, and if the bit is set, avoid this indirection.
Scope of the issue: Affects anyone defining new globals containing Foundation types in the REPL and trying to manipulate them with LLDB commands.
Origination: Introduced when we started building the standard library resiliently
Risk: Very low risk for the Swift change -- it's just adding this new bit.
Reviewed by: @adrian-prantl (in person)
Radar: rdar://problem/39722386