;;; introspection library

;;; This is here as a discussion point, not yet a supported interface.  If
;;; you would like to use the functions here, or you would like other
;;; functions to be here, join the debate on navel@metacircles.com.
;;; List info at http://lists.metacircles.com/cgi-bin/mailman/listinfo/navel

;;; For the avoidance of doubt, the exported interface is the proposed
;;; supported interface.  Anything else is internal, though you're
;;; welcome to argue a case for exporting it.

;;; If you steal the code from this file to cut and paste into your
;;; own project, there will be much wailing and gnashing of teeth.
;;; Your teeth.  If need be, we'll kick them for you.  This is a
;;; contrib, we're allowed to look in internals.  You're an
;;; application programmer, and are not.

;;; TODO
;;; 1) structs don't have within-file location info.  problem for the
;;;   structure itself, accessors and the predicate
;;; 3) error handling.  Signal random errors, or handle and resignal 'our'
;;;   error, or return NIL?
;;; 4) FIXMEs

(defpackage :sb-introspect
  (:use "CL")
  (:export "FUNCTION-ARGLIST"
           "VALID-FUNCTION-NAME-P"
           "FIND-DEFINITION-SOURCE"
           "FIND-DEFINITION-SOURCES-BY-NAME"
           "DEFINITION-SOURCE"
           "DEFINITION-SOURCE-PATHNAME"
           "DEFINITION-SOURCE-FORM-PATH"
           "DEFINITION-SOURCE-CHARACTER-OFFSET"
           "DEFINITION-SOURCE-FILE-WRITE-DATE"
           "DEFINITION-SOURCE-PLIST"
           "DEFINITION-NOT-FOUND" "DEFINITION-NAME"
           "FIND-FUNCTION-CALLEES"
           "FIND-FUNCTION-CALLERS"
           "WHO-BINDS"
           "WHO-CALLS"
           "WHO-REFERENCES"
           "WHO-SETS"
           "WHO-MACROEXPANDS"))

(in-package :sb-introspect)

;;;; Internal interface for SBCL debug info

;;; Here are some tutorial-style type definitions to help understand
;;; the internal SBCL debugging data structures we're using. The
;;; commentary is based on CMUCL's debug internals manual.
;;;
(deftype debug-info ()
  "Structure containing all the debug information related to a function.
Function objects reference debug-infos which in turn reference
debug-sources and so on."
  'sb-c::compiled-debug-info)

(deftype debug-source ()
  "Debug sources describe where to find source code.
For example, the debug source for a function compiled from a file will
include the pathname of the file and the position of the definition."
  'sb-c::debug-source)

(deftype debug-function ()
  "Debug function represent static compile-time information about a function."
  'sb-c::compiled-debug-fun)

(declaim (ftype (function (function) debug-info) function-debug-info))
(defun function-debug-info (function)
  (let* ((function-object (sb-kernel::%closure-fun function))
         (function-header (sb-kernel:fun-code-header function-object)))
    (sb-kernel:%code-debug-info function-header)))

(declaim (ftype (function (function) debug-source) function-debug-source))
(defun function-debug-source (function)
  (debug-info-source (function-debug-info function)))

(declaim (ftype (function (debug-info) debug-source) debug-info-source))
(defun debug-info-source (debug-info)
  (sb-c::debug-info-source debug-info))

(declaim (ftype (function (debug-info) debug-function) debug-info-debug-function))
(defun debug-info-debug-function (debug-info)
  (elt (sb-c::compiled-debug-info-fun-map debug-info) 0))

(defun valid-function-name-p (name)
  "True if NAME denotes a function name that can be passed to MACRO-FUNCTION or FDEFINITION "
  (and (sb-int:valid-function-name-p name) t))

;;;; Finding definitions

(defstruct definition-source
  ;; Pathname of the source file that the definition was compiled from.
  ;; This is null if the definition was not compiled from a file.
  (pathname nil :type (or null pathname))
  ;; Source-path of the definition within the file.
  ;; This may be incomplete depending on the debug level at which the
  ;; source was compiled.
  (form-path '() :type list)
  ;; Character offset of the top-level-form containing the definition.
  ;; This corresponds to the first element of form-path.
  (character-offset nil :type (or null integer))
  ;; File-write-date of the source file when compiled.
  ;; Null if not compiled from a file.
  (file-write-date nil :type (or null integer))
  ;; plist from WITH-COMPILATION-UNIT
  (plist nil)
  ;; Any extra metadata that the caller might be interested in. For
  ;; example the specializers of the method whose definition-source this
  ;; is.
  (description nil :type list))

(defun find-definition-sources-by-name (name type)
  "Returns a list of DEFINITION-SOURCEs for the objects of type TYPE
defined with name NAME. NAME may be a symbol or a extended function
name. Type can currently be one of the following:

   (Public)
   :CLASS
   :COMPILER-MACRO
   :CONDITION
   :CONSTANT
   :FUNCTION
   :GENERIC-FUNCTION
   :MACRO
   :METHOD
   :METHOD-COMBINATION
   :PACKAGE
   :SETF-EXPANDER
   :STRUCTURE
   :SYMBOL-MACRO
   :TYPE
   :VARIABLE

   (Internal)
   :OPTIMIZER
   :SOURCE-TRANSFORM
   :TRANSFORM
   :VOP

If an unsupported TYPE is requested, the function will return NIL.
"
  (flet ((listify (x)
           (if (listp x)
               x
               (list x)))
         (get-class (name)
           (and (symbolp name)
                (find-class name nil)))
         (real-fdefinition (name)
           ;; for getting the real function object, even if the
           ;; function is being profiled
           (let ((profile-info (gethash name sb-profile::*profiled-fun-name->info*)))
             (if profile-info
                 (sb-profile::profile-info-encapsulated-fun profile-info)
                 (fdefinition name)))))
    (listify
     (case type
       ((:variable)
        (when (and (symbolp name)
                   (eq (sb-int:info :variable :kind name) :special))
          (translate-source-location (sb-int:info :source-location type name))))
       ((:constant)
        (when (and (symbolp name)
                   (eq (sb-int:info :variable :kind name) :constant))
          (translate-source-location (sb-int:info :source-location type name))))
       ((:symbol-macro)
        (when (and (symbolp name)
                   (eq (sb-int:info :variable :kind name) :macro))
          (translate-source-location (sb-int:info :source-location type name))))
       ((:macro)
        (when (and (symbolp name)
                   (macro-function name))
          (find-definition-source (macro-function name))))
       ((:compiler-macro)
        (when (compiler-macro-function name)
          (find-definition-source (compiler-macro-function name))))
       ((:function :generic-function)
        (when (and (fboundp name)
                   (or (not (symbolp name))
                       (not (macro-function name))))
          (let ((fun (real-fdefinition name)))
            (when (eq (not (typep fun 'generic-function))
                      (not (eq type :generic-function)))
              (find-definition-source fun)))))
       ((:type)
        (let ((expander-fun (sb-int:info :type :expander name)))
          (when expander-fun
            (find-definition-source expander-fun))))
       ((:method)
        (when (fboundp name)
          (let ((fun (real-fdefinition name)))
           (when (typep fun 'generic-function)
             (loop for method in (sb-mop::generic-function-methods
                                  fun)
                for source = (find-definition-source method)
                when source collect source)))))
       ((:setf-expander)
        (when (and (consp name)
                   (eq (car name) 'setf))
          (setf name (cadr name)))
        (let ((expander (or (sb-int:info :setf :inverse name)
                            (sb-int:info :setf :expander name))))
          (when expander
            (sb-introspect:find-definition-source (if (symbolp expander)
                                                      (symbol-function expander)
                                                      expander)))))
       ((:structure)
        (let ((class (get-class name)))
          (if class
              (when (typep class 'sb-pcl::structure-class)
                (find-definition-source class))
              (when (sb-int:info :typed-structure :info name)
                (translate-source-location
                 (sb-int:info :source-location :typed-structure name))))))
       ((:condition :class)
        (let ((class (get-class name)))
          (when (and class
                     (not (typep class 'sb-pcl::structure-class)))
            (when (eq (not (typep class 'sb-pcl::condition-class))
                      (not (eq type :condition)))
              (find-definition-source class)))))
       ((:method-combination)
        (let ((combination-fun
               (ignore-errors (find-method #'sb-mop:find-method-combination
                                           nil
                                           (list (find-class 'generic-function)
                                                 (list 'eql name)
                                                 t)))))
          (when combination-fun
            (find-definition-source combination-fun))))
       ((:package)
        (when (symbolp name)
          (let ((package (find-package name)))
            (when package
              (find-definition-source package)))))
       ;; TRANSFORM and OPTIMIZER handling from swank-sbcl
       ((:transform)
        (when (symbolp name)
          (let ((fun-info (sb-int:info :function :info name)))
            (when fun-info
              (loop for xform in (sb-c::fun-info-transforms fun-info)
                    for source = (find-definition-source
                                  (sb-c::transform-function xform))
                    for typespec = (sb-kernel:type-specifier
                                    (sb-c::transform-type xform))
                    for note = (sb-c::transform-note xform)
                    do (setf (definition-source-description source)
                             (if (consp typespec)
                                 (list (second typespec) note)
                                 (list note)))
                    collect source)))))
       ((:optimizer)
        (when (symbolp name)
          (let ((fun-info (sb-int:info :function :info name)))
            (when fun-info
              (let ((otypes '((sb-c::fun-info-derive-type . sb-c:derive-type)
                              (sb-c::fun-info-ltn-annotate . sb-c:ltn-annotate)
                              (sb-c::fun-info-ltn-annotate . sb-c:ltn-annotate)
                              (sb-c::fun-info-optimizer . sb-c:optimizer))))
                (loop for (reader . name) in otypes
                      for fn = (funcall reader fun-info)
                      when fn collect
                      (let ((source (find-definition-source fn)))
                        (setf (definition-source-description source)
                              (list name))
                        source)))))))
       ((:vop)
        (when (symbolp name)
          (let ((fun-info (sb-int:info :function :info name)))
            (when fun-info
              (loop for vop in (sb-c::fun-info-templates fun-info)
                    for source = (find-definition-source
                                  (sb-c::vop-info-generator-function vop))
                    do (setf (definition-source-description source)
                             (list (sb-c::template-name vop)
                                   (sb-c::template-note vop)))
                    collect source)))))
       ((:source-transform)
        (when (symbolp name)
          (let ((transform-fun (sb-int:info :function :source-transform name)))
            (when transform-fun
              (sb-introspect:find-definition-source transform-fun)))))
       (t
        nil)))))

(defun find-definition-source (object)
  (typecase object
    ((or sb-pcl::condition-class sb-pcl::structure-class)
     (let ((classoid (sb-impl::find-classoid (class-name object))))
       (when classoid
         (let ((layout (sb-impl::classoid-layout classoid)))
           (when layout
             (translate-source-location
              (sb-kernel::layout-source-location layout)))))))
    (method-combination
     (car
      (find-definition-sources-by-name
       (sb-pcl::method-combination-type-name object) :method-combination)))
    (package
     (translate-source-location (sb-impl::package-source-location object)))
    (class
     (translate-source-location (sb-pcl::definition-source object)))
    ;; Use the PCL definition location information instead of the function
    ;; debug-info for methods and generic functions. Sometimes the
    ;; debug-info would point into PCL internals instead of the proper
    ;; location.
    (generic-function
     (let ((source (translate-source-location
                    (sb-pcl::definition-source object))))
       (when source
         (setf (definition-source-description source)
               (list (sb-mop:generic-function-lambda-list object))))
       source))
    (method
     (let ((source (translate-source-location
                    (sb-pcl::definition-source object))))
       (when source
         (setf (definition-source-description source)
               (append (method-qualifiers object)
                       (if (sb-mop:method-generic-function object)
                           (sb-pcl::unparse-specializers
                            (sb-mop:method-generic-function object)
                            (sb-mop:method-specializers object))
                           (sb-mop:method-specializers object)))))
       source))
    #+sb-eval
    (sb-eval:interpreted-function
     (let ((source (translate-source-location
                    (sb-eval:interpreted-function-source-location object))))
       source))
    (function
     (cond ((struct-accessor-p object)
            (find-definition-source
             (struct-accessor-structure-class object)))
           ((struct-predicate-p object)
            (find-definition-source
             (struct-predicate-structure-class object)))
           (t
            (find-function-definition-source object))))
    ((or condition standard-object structure-object)
     (find-definition-source (class-of object)))
    (t
     (error "Don't know how to retrieve source location for a ~S~%"
            (type-of object)))))

(defun find-function-definition-source (function)
  (let* ((debug-info (function-debug-info function))
         (debug-source (debug-info-source debug-info))
         (debug-fun (debug-info-debug-function debug-info))
         (tlf (if debug-fun (sb-c::compiled-debug-fun-tlf-number debug-fun))))
    (make-definition-source
     :pathname
     (if (eql (sb-c::debug-source-from debug-source) :file)
         (parse-namestring (sb-c::debug-source-name debug-source)))
     :character-offset
     (if tlf
         (elt (sb-c::debug-source-start-positions debug-source) tlf))
     ;; Unfortunately there is no proper source path available in the
     ;; debug-source. FIXME: We could use sb-di:code-locations to get
     ;; a full source path. -luke (12/Mar/2005)
     :form-path (if tlf (list tlf))
     :file-write-date (sb-c::debug-source-created debug-source)
     :plist (sb-c::debug-source-plist debug-source))))

(defun translate-source-location (location)
  (if location
      (make-definition-source
       :pathname (let ((n (sb-c:definition-source-location-namestring location)))
                   (when n
                     (parse-namestring n)))
       :form-path
       (let ((number (sb-c:definition-source-location-toplevel-form-number
                         location)))
         (when number
           (list number)))
       :plist (sb-c:definition-source-location-plist location))
      (make-definition-source)))

;;; This is kludgey.  We expect these functions (the underlying functions,
;;; not the closures) to be in static space and so not move ever.
;;; FIXME It's also possibly wrong: not all structures use these vanilla
;;; accessors, e.g. when the :type option is used
(defvar *struct-slotplace-reader*
  (sb-vm::%simple-fun-self #'definition-source-pathname))
(defvar *struct-slotplace-writer*
  (sb-vm::%simple-fun-self #'(setf definition-source-pathname)))
(defvar *struct-predicate*
  (sb-vm::%simple-fun-self #'definition-source-p))

(defun struct-accessor-p (function)
  (let ((self (sb-vm::%simple-fun-self function)))
    ;; FIXME there are other kinds of struct accessor.  Fill out this list
    (member self (list *struct-slotplace-reader*
                       *struct-slotplace-writer*))))

(defun struct-predicate-p (function)
  (let ((self (sb-vm::%simple-fun-self function)))
    ;; FIXME there may be other structure predicate functions
    (member self (list *struct-predicate*))))

;;; FIXME: maybe this should be renamed as FUNCTION-LAMBDA-LIST?
(defun function-arglist (function)
  "Describe the lambda list for the extended function designator FUNCTION.
Works for special-operators, macros, simple functions,
interpreted functions, and generic functions.  Signals error if
not found"
  (cond ((valid-function-name-p function)
         (function-arglist (or (and (symbolp function)
                                    (macro-function function))
                               (fdefinition function))))
        ((typep function 'generic-function)
         (sb-pcl::generic-function-pretty-arglist function))
        #+sb-eval
        ((typep function 'sb-eval:interpreted-function)
         (sb-eval:interpreted-function-lambda-list function))
        (t (sb-kernel:%simple-fun-arglist (sb-kernel:%fun-fun function)))))

(defun struct-accessor-structure-class (function)
  (let ((self (sb-vm::%simple-fun-self function)))
    (cond
      ((member self (list *struct-slotplace-reader* *struct-slotplace-writer*))
       (find-class
        (sb-kernel::classoid-name
         (sb-kernel::layout-classoid
          (sb-kernel:%closure-index-ref function 1)))))
      )))

(defun struct-predicate-structure-class (function)
  (let ((self (sb-vm::%simple-fun-self function)))
    (cond
      ((member self (list *struct-predicate*))
       (find-class
        (sb-kernel::classoid-name
         (sb-kernel::layout-classoid
          (sb-kernel:%closure-index-ref function 0)))))
      )))

;;;; find callers/callees, liberated from Helmut Eller's code in SLIME

;;; This interface is trmendously experimental.

;;; For the moment I'm taking the view that FDEFN is an internal
;;; object (one out of one CMUCL developer surveyed didn't know what
;;; they were for), so these routines deal in FUNCTIONs

;;; Find callers and callees by looking at the constant pool of
;;; compiled code objects.  We assume every fdefn object in the
;;; constant pool corresponds to a call to that function.  A better
;;; strategy would be to use the disassembler to find actual
;;; call-sites.

(defun find-function-callees (function)
  "Return functions called by FUNCTION."
  (let ((callees '()))
    (map-code-constants
     (sb-kernel:fun-code-header function)
     (lambda (obj)
       (when (sb-kernel:fdefn-p obj)
         (push (sb-kernel:fdefn-fun obj)
               callees))))
    callees))


(defun find-function-callers (function &optional (spaces '(:read-only :static
                                                           :dynamic)))
  "Return functions which call FUNCTION, by searching SPACES for code objects"
  (let ((referrers '()))
    (map-caller-code-components
     function
     spaces
     (lambda (code)
       (let ((entry (sb-kernel:%code-entry-points  code)))
         (cond ((not entry)
                (push (princ-to-string code) referrers))
               (t
                (loop for e = entry then (sb-kernel::%simple-fun-next e)
                      while e
                      do (pushnew e referrers)))))))
    referrers))

(declaim (inline map-code-constants))
(defun map-code-constants (code fn)
  "Call FN for each constant in CODE's constant pool."
  (check-type code sb-kernel:code-component)
  (loop for i from sb-vm:code-constants-offset below
        (sb-kernel:get-header-data code)
        do (funcall fn (sb-kernel:code-header-ref code i))))

(declaim (inline map-allocated-code-components))
(defun map-allocated-code-components (spaces fn)
  "Call FN for each allocated code component in one of SPACES.  FN
receives the object and its size as arguments.  SPACES should be a
list of the symbols :dynamic, :static, or :read-only."
  (dolist (space spaces)
    (sb-vm::map-allocated-objects
     (lambda (obj header size)
       (when (= sb-vm:code-header-widetag header)
         (funcall fn obj size)))
     space
     t)))

(declaim (inline map-caller-code-components))
(defun map-caller-code-components (function spaces fn)
  "Call FN for each code component with a fdefn for FUNCTION in its
constant pool."
  (let ((function (coerce function 'function)))
    (map-allocated-code-components
     spaces
     (lambda (obj size)
       (declare (ignore size))
       (map-code-constants
        obj
        (lambda (constant)
          (when (and (sb-kernel:fdefn-p constant)
                     (eq (sb-kernel:fdefn-fun constant)
                         function))
            (funcall fn obj))))))))

;;; XREF facility

(defun get-simple-fun (functoid)
  (etypecase functoid
    (sb-kernel::fdefn
     (get-simple-fun (sb-vm::fdefn-fun functoid)))
    ((or null sb-impl::funcallable-instance)
     nil)
    (function
     (sb-kernel::%closure-fun functoid))))

(defun collect-xref (kind-index wanted-name)
  (let ((ret nil))
    (dolist (env sb-c::*info-environment* ret)
      ;; Loop through the infodb ...
      (sb-c::do-info (env :class class :type type :name info-name
                          :value value)
        ;; ... looking for function or macro definitions
        (when (and (eql class :function)
                   (or (eql type :macro-function)
                       (eql type :definition)))
          ;; Get a simple-fun for the definition, and an xref array
          ;; from the table if available.
          (let* ((simple-fun (get-simple-fun value))
                 (xrefs (when simple-fun
                          (sb-vm::%simple-fun-xrefs simple-fun)))
                 (array (when xrefs
                          (aref xrefs kind-index))))
            ;; Loop through the name/path xref entries in the table
            (loop for i from 0 below (length array) by 2
                  for xref-name = (aref array i)
                  for xref-path = (aref array (1+ i))
                  do (when (eql xref-name wanted-name)
                       (let ((source-location
                              (find-function-definition-source simple-fun)))
                         ;; Use the more accurate source path from
                         ;; the xref entry.
                         (setf (definition-source-form-path source-location)
                               xref-path)
                         (push (cons info-name source-location)
                               ret))))))))))

(defun who-calls (function-name)
  "Use the xref facility to search for source locations where the
global function named FUNCTION-NAME is called. Returns a list of
function name, definition-source pairs."
  (collect-xref #.(position :calls sb-c::*xref-kinds*) function-name))

(defun who-binds (symbol)
  "Use the xref facility to search for source locations where the
special variable SYMBOL is rebound. Returns a list of function name,
definition-source pairs."
  (collect-xref #.(position :binds sb-c::*xref-kinds*) symbol))

(defun who-references (symbol)
  "Use the xref facility to search for source locations where the
special variable or constant SYMBOL is read. Returns a list of function
name, definition-source pairs."
  (collect-xref #.(position :references sb-c::*xref-kinds*) symbol))

(defun who-sets (symbol)
  "Use the xref facility to search for source locations where the
special variable SYMBOL is written to. Returns a list of function name,
definition-source pairs."
  (collect-xref #.(position :sets sb-c::*xref-kinds*) symbol))

(defun who-macroexpands (macro-name)
  "Use the xref facility to search for source locations where the
macro MACRO-NAME is expanded. Returns a list of function name,
definition-source pairs."
  (collect-xref #.(position :macroexpands sb-c::*xref-kinds*) macro-name))

(provide 'sb-introspect)
