PrintAsClang is supposed to emit declarations in the same order regardless of the compiler’s internal state, but we have repeatedly found that our current criteria are inadequate, resulting in non-functionality-affecting changes to generated header content. Add a diagnostic that’s emitted when this happens soliciting a bug report.
Since there *should* be no cases where the compiler fails to order declarations, this diagnostic is never actually emitted. Instead, we test this change by enabling `-verify` on nearly all PrintAsClang tests to make sure they are unaffected.
This did demonstrate a missing criterion that only mattered in C++ mode: extensions that varied only in their generic signature were not sorted stably. Add a sort criterion for this.
Currently headers produced with `-emit-objc-header` /
`-emit-objc-header-path` produce headers that include modular imports.
If the consumer wishes to operate without modules enabled, these headers
cannot be used. This patch introduces a new flag
(`-emit-clang-header-nonmodular-includes`) that when enabled
attempts to argument each modular import included in such a header with
a set of equivalent textual imports.
Currently headers produced with `-emit-objc-header` /
`-emit-objc-header-path` produce headers that include modular imports.
If the consumer wishes to operate without modules enabled, these headers
cannot be used. This patch introduces a new flag
(`-emit-clang-header-nonmodular-includes`) that when enabled
attempts to argument each modular import included in such a header with
a set of equivalent textual imports.
