[cfe-commits] r38550 - /cfe/cfe/trunk/README.txt

[sabre at cs.uiuc.edu]

Author: sabre
Date: Wed Jul 11 11:22:29 2007
New Revision: 38550

URL: http://llvm.org/viewvc/llvm-project?rev=38550&view=rev
Log:
Add a bunch more forward looking notes

Modified:
    cfe/cfe/trunk/README.txt

Modified: cfe/cfe/trunk/README.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/cfe/trunk/README.txt?rev=38550&r1=38549&r2=38550&view=diff

==============================================================================
--- cfe/cfe/trunk/README.txt (original)
+++ cfe/cfe/trunk/README.txt Wed Jul 11 11:22:29 2007
@@ -57,4 +57,67 @@
  
 Parser Actions:
  * All.
+ * Need some way to effeciently either work in 'callback'/devkit mode or in
+   default AST building mode.
+
+Fast #Import:
+ * All.
+ * 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?
+ * 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.
+
+New language feature: Configuration queries:
+  - Instead of #ifdef __POWERPC__, use "if (strcmp(`cpu`, __POWERPC__))", or
+    some other syntax.
+  - Use it to increase the number of "architecture-clean" #import'd files.
+
+Cocoa GUI Front-end:
+ * All.
+ * Start with very simple "textedit" GUI.
+ * Trivial project model: list of files, list of cmd line options.
+ * Build simple developer examples.
+ * Tight integration with compiler components.
+ * Primary advantage: batch compiles, keeping digests in memory, dependency mgmt
+   between app frameworks, building code/digests in the background, etc.
  
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