remove some overly-crazy ideas.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63614 91177308-0d34-0410-b5e6-96231b3b80d8

NOTES.txt

@@ -48,55 +48,6 @@ TODO: File Manager Speedup:
    3. Reading the dir uses the getdirentries syscall, creating an FileEntry
       for all files found.
 
-//===---------------------------------------------------------------------===//
-
-TODO: Fast #Import:
-
- * Get frameworks that don't use #import to do so, e.g. 
-   DirectoryService, AudioToolbox, CoreFoundation, etc.  Why not using #import?
-   Because they work in C mode? C has #import.
- * Have the lexer return a token for #import instead of handling it itself.
-   - Create a new preprocessor object with no external state (no -D/U options
-     from the command line, etc).  Alternatively, keep track of exactly which
-     external state is used by a #import: declare it somehow.
- * When having reading a #import file, keep track of whether we have (and/or
-   which) seen any "configuration" macros.  Various cases:
-   - Uses of target args (__POWERPC__, __i386): Header has to be parsed 
-     multiple times, per-target.  What about #ifndef checks?  How do we know?
-   - "Configuration" preprocessor macros not defined: POWERPC, etc.  What about
-     things like __STDC__ etc?  What is and what isn't allowed.
- * Special handling for "umbrella" headers, which just contain #import stmts:
-   - Cocoa.h/AppKit.h - Contain pointers to digests instead of entire digests
-     themselves?  Foundation.h isn't pure umbrella!
- * Frameworks digests:
-   - Can put "digest" of a framework-worth of headers into the framework
-     itself.  To open AppKit, just mmap
-     /System/Library/Frameworks/AppKit.framework/"digest", which provides a
-     symbol table in a well defined format.  Lazily unstream stuff that is
-     needed.  Contains declarations, macros, and debug information.
-   - System frameworks ship with digests.  How do we handle configuration
-     information?  How do we handle stuff like:
-       #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_2
-     which guards a bunch of decls?  Should there be a couple of default
-     configs, then have the UI fall back to building/caching its own?
-   - GUI automatically builds digests when UI is idle, both of system
-     frameworks if they aren't not available in the right config, and of app
-     frameworks.
-   - GUI builds dependence graph of frameworks/digests based on #imports.  If a
-     digest is out date, dependent digests are automatically invalidated.
-
- * New constraints on #import for objc-v3:
-   - #imported file must not define non-inline function bodies.
-     - Alternatively, they can, and these bodies get compiled/linked *once*
-       per app into a dylib.  What about building user dylibs?
-   - Restrictions on ObjC grammar: can't #import the body of a for stmt or fn.
-   - Compiler must detect and reject these cases.
-   - #defines defined within a #import have two behaviors:
-     - By default, they escape the header.  These macros *cannot* be #undef'd
-       by other code: this is enforced by the front-end.
-     - Optionally, user can specify what macros escape (whitelist) or can use
-       #undef.
-
 //===---------------------------------------------------------------------===//
 // Specifying targets:  -triple and -arch
 ===---------------------------------------------------------------------===//