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Re: [objc] exception handling rewrite; gnu runtime operational


On Fri, Jun 18, 2004 at 11:41:54PM +0200, David Ayers wrote:
> #define TAG_EXCEPTIONEXTRACT		"objc_exception_extract"

This retrieves the exception object from the setjmp struct.  For
gcc native exceptions this is handled behind the scenes and is
represented in the tree data structures by EXC_PTR_EXPR.

> #define TAG_EXCEPTIONTRYENTER		"objc_exception_try_enter"
> #define TAG_EXCEPTIONTRYEXIT		"objc_exception_try_exit"

These manage the setjmp struct.  Natually not needed for gcc
native exceptions.

> #define TAG_EXCEPTIONMATCH		"objc_exception_match"

Determines if the catch type matches the exception object.

This is handled by isKindOf in libobjc/exception.c.  Note
the comment there wondering if we needed something more
than the simplistic check there.

> #define TAG_EXCEPTIONTHROW		"objc_exception_throw"

Already replicated in libobjc/exception.c.  I don't think
there's anything otherwise necessary, modulo potential
out-of-memory concerns.

> #define TAG_SYNCENTER			"objc_sync_enter"
> #define TAG_SYNCEXIT			"objc_sync_exit"

Need to be implemented.

> #define TAG_SETJMP			"_setjmp"

Duh.

> #define UTAG_EXCDATA			"_objc_exception_data"
> #define UTAG_EXCDATA_VAR		"_stackExceptionData"
> #define UTAG_CAUGHTEXC_VAR		"_caughtException"
> #define UTAG_RETHROWEXC_VAR		"_rethrowException"

These were *local* data variable names used during the generation
of code.  Now handled in the new code by objc_create_temporary.


r~


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