Implement statistical errortrace-based profiling.

Add a mode to the profiler to use continuation marks inserted
by the errortrace annotator instead of the runtime.

Split `syntax/source-syntax` out from Typed Racket as a separate package,
and use it to give better names for errortrace stack frames.
Use caching to speed it up substantially when called repeatedly (as
errortrace does).

Also, document (internally) the format used by errortrace marks.

original commit: 1e7eb34ba170b6aad77ee67c0f4b802950ff1a4b

pkgs/profile-pkgs/profile-doc/info.rkt

@@ -5,6 +5,8 @@
 (define build-deps '("base"
                      "scribble-lib"
                      "profile-lib"
+                     "errortrace-doc"
+                     "errortrace-lib"
                      "racket-doc"))
 
 (define pkg-desc "documentation part of \"profile\"")

pkgs/profile-pkgs/profile-doc/profile/scribblings/sampler.scrbl

@@ -1,7 +1,8 @@
 #lang scribble/doc
 
 @(require scribble/manual
-          (for-label racket/base racket/contract profile/sampler profile/analyzer))
+          (for-label racket/base racket/contract profile/sampler profile/analyzer
+                     errortrace/errortrace-key))
 
 @title[#:tag "sampler"]{Collecting Profile Information}
 
@@ -11,7 +12,8 @@
                                          (listof (or/c thread? custodian?)))]
                          [delay (>=/c 0.0)]
                          [super-cust custodian? (current-custodian)]
-                         [custom-keys (listof any/c) '()])
+                         [custom-keys (listof any/c) '()]
+                         [#:use-errortrace? use-errortrace? any/c #f])
          ((symbol?) (any/c) . ->* . any/c)]{
 
 Creates a stack-snapshot collector thread, which tracks the given
@@ -26,6 +28,10 @@ When @racket[custom-keys] are provided, the sampler takes snapshots of the
 continuation marks corresponding to the given keys, in addition to taking
 snapshots of the stack.
 
+When @racket[use-errortrace?] is not @racket[#f], the @racket[errortrace-key] is 
+used to sample snapshots instead of the implicit key used by 
+@racket[continuation-mark-set->context].
+
 The resulting value is a controller function, which consumes a message
 consisting of a symbol and an optional argument, and can affect the
 sampler.  The following messages are currently supported:

pkgs/profile-pkgs/profile-doc/profile/scribblings/toplevel.scrbl

@@ -2,6 +2,7 @@
 
 @(require scribble/manual
           (for-label racket/base racket/contract profile profile/sampler
+                     errortrace/errortrace-lib
                      (only-in profile/analyzer analyze-samples profile?)
                      (prefix-in text: profile/render-text)))
 
@@ -23,7 +24,8 @@ intended as a convenient tool for profiling code.
           [#:periodic-renderer periodic-renderer
            (or/c #f (list/c (>=/c 0.0)
                             (profile? . -> . any/c)))
-           #f])
+           #f]
+          [#:use-errortrace? use-errortrace? any/c #f])
          void?]{
 
 Executes the given @racket[thunk] and collect profiling data during
@@ -40,6 +42,14 @@ can customize the profiling:
   actually sampled.  (The @racket[delay] value is passed on to
   @racket[create-sampler], which creates the sampler thread.)}
  
+@item{When @racket[use-errortrace?] is not @racket[#f], more accurate
+  stack snapshots are captured using 
+  @other-doc['(lib "errortrace/scribblings/errortrace.scrbl")]. Note that
+  when this is provided, it will only profile uncompiled files and files
+  compiled while using @racket[errortrace-compile-handler], and the profiled program
+  must be run using @commandline{racket -l errortrace -t program.rkt}
+  Removing compiled files (with extension @tt{.zo}) is sufficient to enable this.}
+
 @item{Due to the statistical nature of the profiler, longer executions
   result in more accurate analysis.  You can specify a number of
   @racket[iterations] to repeat the @racket[thunk] to collect more

pkgs/profile-pkgs/profile-lib/info.rkt

@@ -1,7 +1,7 @@
 #lang info
 
 (define collection "profile")
-(define deps '("base"))
+(define deps '("base" "errortrace-lib"))
 (define build-deps '("at-exp-lib"
                      "rackunit-lib"))
 

pkgs/profile-pkgs/profile-lib/main.rkt

@@ -11,12 +11,14 @@
                        #:repeat  [rpt 1]
                        #:threads [threads? #f]
                        #:render  [renderer text:render]
-                       #:periodic-renderer [periodic-renderer #f])
+                       #:periodic-renderer [periodic-renderer #f]
+                       #:use-errortrace? [et? #f])
   (define cust (and threads? (make-custodian (current-custodian))))
   (define sampler (create-sampler (if threads?
                                     (list cust (current-thread))
                                     (current-thread))
-                                  delay))
+                                  delay
+                                  #:use-errortrace? et?))
   (define periodic-thread
     (and periodic-renderer
          (let ([delay (car periodic-renderer)]

pkgs/profile-pkgs/profile-lib/sampler.rkt

@@ -6,8 +6,24 @@
 
 (provide create-sampler)
 
+(require errortrace/errortrace-key)
+
+;; (cons sexp srcloc) -> (cons symbol srcloc)
+;; just take the first symbol we find
+(define (errortrace-preprocess frame)
+  (cons (and (car frame)
+             (let loop ([e (car frame)])
+               (cond [(symbol? e) e]
+                     [(pair? e) (loop (car e))]
+                     [else (error 'errortrace-preprocess
+                                  "unexpected frame: ~a" frame)])))
+        (and (cdr frame)
+             (apply srcloc (cdr frame)))))
+
 ;; create-sampler : creates a sample collector thread, which tracks the given
 ;; `to-track' value every `delay' seconds.
+;; Uses errortrace annotations when #:use-errortrace? is specified, otherwise
+;;   uses the native stack traces provided by `cms->context`.
 ;; * The input value can be either a thread (track just that thread), a
 ;;   custodian (track all threads managed by the custodian), or a list of
 ;;   threads and/or custodians.  If a custodian is given, it must be
@@ -57,7 +73,8 @@
 ;;     same format as the output of continuation-mark-set->list*.
 (define (create-sampler to-track delay
                         [super-cust  (current-custodian)]
-                        [custom-keys #f])
+                        [custom-keys #f]
+                        #:use-errortrace? [do-errortrace #f])
   ;; the collected data
   (define snapshots '())
   ;; listof (cons continuation-mark-key value/#f)
@@ -116,9 +133,15 @@
                  (set! snapshots
                        (cons (list* (thread-id t)
                                     (current-process-milliseconds t)
+                                    (if do-errortrace
+                                        (for/list ([frame (in-list
+                                                           (continuation-mark-set->list
+                                                            (continuation-marks t)
+                                                            errortrace-key))])
+                                            (intern-entry (errortrace-preprocess frame)))
                                         (map intern-entry
                                              (continuation-mark-set->context
-                                          (continuation-marks t))))
+                                              (continuation-marks t)))))
                              snapshots)))]
               [(custodian? t)
                (for-each loop (custodian-managed-list t super-cust))]