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- To: firstname.lastname@example.org
- Subject: Issue PROCLAIM-INLINE-WHERE
- From: David N Gray <Gray@DSG.csc.ti.com>
- Date: Fri, 16 Sep 88 20:33:08 CDT
- Sender: GRAY@Kelvin.csc.ti.com
References: CLtL p. 156, 159
Edit History: 16 Sept. 88 V1 by David Gray
Status: For preliminary discussion
CLtL does not specify whether a (PROCLAIM '(INLINE ...)) should come
before or after the DEFUNs that it refers to, but in most
implementations the compiler can't expand a function inline
unless it knows at the time it processes the DEFUN that the definition
needs to be saved for use in inline expansion.
Clarify that (PROCLAIM '(INLINE ...)) tells the compiler both that it is
desirable to use inline expansion for calls to the functions indicated
and that the compilation of any subsequent DEFUN of one of the functions
should record whatever information is used for performing inline
expansions. Consequently, the proclamation should precede the
definition of the functions that it names. When compiling a function
call, if the function has been proclaimed INLINE but the current
definition of the function was established before the PROCLAIM was
processed, it is implementation-dependent whether the function will
actually be expanded inline.
This clarification brings the specification in line with current
practice. The only alternative would appear to be to require the
compiler to always save the definition of every function, and that
doesn't seem reasonable.
Given the following input to COMPILE-FILE, does F1 get expanded inline
(defun f1 (a) (+ a 100))
(proclaim '(inline f1))
(defun f2 (b) (f1 b))
The documentation for Lucid and the TI Explorer both say that INLINE
proclamations need to precede the function definition. Symbolics
doesn't appear to document this, but requires it anyway. Thus none of
these three implementations do the inline expansion in the example
Cost to implementors:
Probably none required, although given this clarification it would be
nice if compilers warned about an INLINE proclamation that follows the
indicated DEFUN in the same file.
Cost to users:
Users will know how to use INLINE proclamations correctly.
Costs of Non-Adoption:
Continued confusion over cases such as the example above, which
conform to CLtL but don't do what is expected.