bug#22114: 24.5; [PATCH] Allow profiler.el to display reports after stopping

[Vasilij Schneidermann <v.schneidermann@gmail.com>]

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On 12/13/15 at 09:33pm, Vasilij Schneidermann wrote:
> What if one would just create a deep copy of the log that can be
> safely used externally?

Apparently not even that is necessary.  I wrote another variant of the
patch that disables the check for a running profiler before generating a
report, avoids erroring out if generating a report for a non-running
profiler and doesn't reset the log after stopping.  Either my testing
has been too superficial and something unexpected will come bite me or
the comments are simply outdated.

I've taken the liberty to include Paul Eggert and Stefan Monnier into
the CC as they've contributed several patches to profiler.c and should
be able to illuminate this matter.

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From 7153c42d55d14ad6d367f4e7f8a5482cb814e810 Mon Sep 17 00:00:00 2001
From: Vasilij Schneidermann <v.schneidermann@gmail.com>
Date: Sun, 13 Dec 2015 23:09:12 +0100
Subject: [PATCH] Disable profiler log reset on stop

---
 lisp/profiler.el | 31 +++++++++++++++----------------
 src/profiler.c   | 16 +---------------
 2 files changed, 16 insertions(+), 31 deletions(-)

diff --git a/lisp/profiler.el b/lisp/profiler.el
index f28bbfe..90a4241 100644
--- a/lisp/profiler.el
+++ b/lisp/profiler.el
@@ -216,19 +216,17 @@ Optional argument MODE means only check for the specified mode (cpu or mem)."
 
 (defun profiler-cpu-profile ()
   "Return CPU profile."
-  (when (profiler-running-p 'cpu)
-    (profiler-make-profile
-     :type 'cpu
-     :timestamp (current-time)
-     :log (profiler-cpu-log))))
+  (profiler-make-profile
+   :type 'cpu
+   :timestamp (current-time)
+   :log (profiler-cpu-log)))
 
 (defun profiler-memory-profile ()
   "Return memory profile."
-  (when (profiler-memory-running-p)
-    (profiler-make-profile
-     :type 'memory
-     :timestamp (current-time)
-     :log (profiler-memory-log))))
+  (profiler-make-profile
+   :type 'memory
+   :timestamp (current-time)
+   :log (profiler-memory-log)))
 
 \f
 ;;; Calltrees
@@ -845,20 +843,21 @@ Also, if MODE is `mem' or `cpu+mem', then memory profiler will be started."
   t)
 
 (defun profiler-report-cpu ()
+  (when (profiler-cpu-log))
   (let ((profile (profiler-cpu-profile)))
-    (when profile
-      (profiler-report-profile-other-window profile))))
+    (profiler-report-profile-other-window profile)))
 
 (defun profiler-report-memory ()
   (let ((profile (profiler-memory-profile)))
-    (when profile
-      (profiler-report-profile-other-window profile))))
+    (profiler-report-profile-other-window profile)))
 
 (defun profiler-report ()
   "Report profiling results."
   (interactive)
-  (profiler-report-cpu)
-  (profiler-report-memory))
+  (when (and (fboundp 'profiler-cpu-log) (profiler-cpu-log))
+    (profiler-report-cpu))
+  (when (profiler-memory-log)
+    (profiler-report-memory)))
 
 ;;;###autoload
 (defun profiler-find-profile (filename)
diff --git a/src/profiler.c b/src/profiler.c
index efdb1d9..4cd6bb0 100644
--- a/src/profiler.c
+++ b/src/profiler.c
@@ -41,9 +41,7 @@ static Lisp_Object
 make_log (EMACS_INT heap_size, EMACS_INT max_stack_depth)
 {
   /* We use a standard Elisp hash-table object, but we use it in
-     a special way.  This is OK as long as the object is not exposed
-     to Elisp, i.e. until it is returned by *-profiler-log, after which
-     it can't be used any more.  */
+     a special way.  */
   Lisp_Object log = make_hash_table (hashtest_profiler,
 				     make_number (heap_size),
 				     make_float (DEFAULT_REHASH_SIZE),
@@ -412,12 +410,6 @@ Before returning, a new log is allocated for future samples.  */)
   (void)
 {
   Lisp_Object result = cpu_log;
-  /* Here we're making the log visible to Elisp, so it's not safe any
-     more for our use afterwards since we can't rely on its special
-     pre-allocated keys anymore.  So we have to allocate a new one.  */
-  cpu_log = (profiler_cpu_running
-	     ? make_log (profiler_log_size, profiler_max_stack_depth)
-	     : Qnil);
   Fputhash (Fmake_vector (make_number (1), Qautomatic_gc),
 	    make_number (cpu_gc_count),
 	    result);
@@ -487,12 +479,6 @@ Before returning, a new log is allocated for future samples.  */)
   (void)
 {
   Lisp_Object result = memory_log;
-  /* Here we're making the log visible to Elisp , so it's not safe any
-     more for our use afterwards since we can't rely on its special
-     pre-allocated keys anymore.  So we have to allocate a new one.  */
-  memory_log = (profiler_memory_running
-		? make_log (profiler_log_size, profiler_max_stack_depth)
-		: Qnil);
   return result;
 }
 
-- 
2.6.2