| blob | ba2e7b2411351f46e37b4978a783735edf94ace4 |
1 ;;;; This file contains stuff that was split out from 'globaldb.lisp'
2 ;;;; to satisfy build-order constraints.
4 ;;;; This software is part of the SBCL system. See the README file for
5 ;;;; more information.
6 ;;;;
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
13 ;;; Given the presence of docstrings and source locations,
14 ;;; this logic arguably belongs to the runtime kernel, not the compiler,
15 ;;; but such nuance isn't hugely important.
22 ;;; At run time, we represent the type of a piece of INFO in the globaldb
23 ;;; by a small integer between 1 and 63. [0 is reserved for internal use.]
24 ;;; CLISP, and maybe others, need EVAL-WHEN because without it, the constant
25 ;;; is not seen by the "#." expression a few lines down.
30 ;;; A map from info-number to its META-INFO object.
31 ;;; The reverse mapping is obtained by reading the META-INFO.
37 (:constructor
39 type-checker validate-function default))
41 ;; a number that uniquely identifies this object
43 ;; 2-part key to this piece of metainfo
46 ;; a type specifier which info of this type must satisfy
48 ;; Two functions called by (SETF INFO) before calling SET-INFO-VALUE.
49 ;; 1. A function that type-checks its argument and returns it,
50 ;; or signals an error.
51 ;; Some Lisps trip over their shoelaces trying to assert that
52 ;; a function is (function (t) t). Our code is fine though.
55 ;; 2. a function of two arguments, a name and new-value, which performs
56 ;; any other checks and/or side-effects including signaling an error.
58 ;; If FUNCTIONP, then a function called when there is no information of
59 ;; this type. If not FUNCTIONP, then any object serving as a default.
66 ;; Refer to info-vector.lisp for the meaning of this constant.
69 ;;; SYMBOL-INFO is a primitive object accessor defined in 'objdef.lisp'
70 ;;; But in the host Lisp, there is no such thing as a symbol-info slot.
71 ;;; Instead, symbol-info is kept in the host symbol's plist.
72 #+sb-xc-host
75 ;; Perform the equivalent of (GET-INFO-VALUE KIND +INFO-METAINFO-TYPE-NUM+)
76 ;; but skipping the defaulting logic.
77 ;; Return zero or more META-INFOs that match on KIND, which is usually
78 ;; - though not always - a unique identifier for the (:TYPE :KIND) pair.
79 ;; Note that bypassing of defaults is critical for bootstrapping,
80 ;; since INFO is used to retrieve its own META-INFO at system-build time.
88 ;; (UNSIGNED-BYTE 16) is an arbitrarily generous limit on the number of
89 ;; cells in an info-vector. Most vectors have a fewer than a handful of things,
90 ;; and performance would need to be re-thought if more than about a dozen
91 ;; cells were in use. (It would want to become hash-based probably)
94 packed-info-value-index))
96 ;; Return the META-INFO object for CATEGORY and KIND, signaling an error
97 ;; if not found and ERRORP is non-nil. Note that the two-level logical hierarchy
98 ;; of CATEGORY + KIND is physically grouped by KIND first, then CATEGORY.
99 ;; e.g. Searching for (:SETF :EXPANDER) searches for :EXPANDER and finds
100 ;; (#<:CAS :EXPANDER, 44> #<:SETF :EXPANDER, 43> #<:TYPE :EXPANDER, 25>)
101 ;; from which one is picked. This is slightly faster than searching first by
102 ;; CATEGORY, because in the case of :FUNCTION there would be ~11 things to sift
103 ;; through, whereas typically no more than 3 or 4 items have the same KIND.
104 ;;
110 category)
113 metadata)))
114 ;; !GET-META-INFOS enforces that KIND is a symbol, therefore
115 ;; if a metaobject was found, CATEGORY was necessarily a symbol too.
116 ;; Otherwise, if the caller wants no error to be signaled on missing info,
117 ;; we must nevertheless enforce that CATEGORY was actually a symbol.
122 ;;; Compiler macros for INFO functions.
123 ;;;
124 ;;; These are defined ASAP so that when building the cross-compiler, all calls
125 ;;; occurring after compilation of "globaldb" (for known constant meta-info)
126 ;;; are transformed; and when executing the cross-compiler, *all* inlineable
127 ;;; calls for known constant meta-info are transformed;
128 ;;; and when running target code, calls with legal constants for the first two
129 ;;; arguments are transformed.
135 ;; In the target Lisp, it's a STYLE-WARNING if this macro
136 ;; defers to a full call to #'INFO.
137 ;; If the cross-compilation host, if any info-type is
138 ;; defined, then it's an error not to find the meta-info.
139 ;; If no info-types are defined, silently defer.
144 ,form
146 #-sb-xc-host
148 category kind)
149 .whole.)))
150 .whole.))))
162 ;; is (or ... null), but non-null at macroexpansion time
163 ;; implies non-null at runtime.
169 ;; enforce type-correctness regardless of enclosing policy
179 ;; Perform the approximate equivalent operations of retrieving
180 ;; (INFO :CATEGORY :KIND NAME), but if no info is found, invoke CREATION-FORM
181 ;; to produce an object that becomes the value for that piece of info, storing
182 ;; and returning it. The entire sequence behaves atomically but with a proviso:
183 ;; the creation form's result may be discarded, and another object returned
184 ;; instead (presumably) from another thread's execution of the creation form.
185 ;; If constructing the object has either non-trivial cost, or deleterious
186 ;; side-effects from making and discarding its result, do NOT use this macro.
187 ;; A mutex-guarded table would probably be more appropriate in such cases.
188 ;;