1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M - S T A C K _ U S A G E --
9 -- Copyright (C) 2004-2010, Free Software Foundation, Inc. --
11 -- GNARL is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
30 ------------------------------------------------------------------------------
32 with System.Parameters;
36 package body System.Stack_Usage is
37 use System.Storage_Elements;
46 -- Stackl_Slots is an internal data type to represent a sequence of real
47 -- stack slots initialized with a provided pattern, with operations to
48 -- abstract away the target call stack growth direction.
50 type Stack_Slots is array (Integer range <>) of Pattern_Type;
51 for Stack_Slots'Component_Size use Pattern_Type'Object_Size;
53 -- We will carefully handle the initializations ourselves and might want
54 -- to remap an initialized overlay later on with an address clause.
56 pragma Suppress_Initialization (Stack_Slots);
58 -- The abstract Stack_Slots operations all operate over the simple array
61 -- memory addresses increasing ---->
63 -- Slots('First) Slots('Last)
66 -- +------------------------------------------------------------------+
68 -- +------------------------------------------------------------------+
70 -- What we call Top or Bottom always denotes call chain leaves or entry
71 -- points respectively, and their relative positions in the stack array
72 -- depends on the target stack growth direction:
76 -- <----- calls push frames towards decreasing addresses
78 -- Top(most) Slot Bottom(most) Slot
81 -- +------------------------------------------------------------------+
82 -- |####| | leaf frame | ... | entry frame |
83 -- +------------------------------------------------------------------+
87 -- calls push frames towards increasing addresses ----->
89 -- Bottom(most) Slot Top(most) Slot
92 -- +------------------------------------------------------------------+
93 -- | entry frame | ... | leaf frame | |####|
94 -- +------------------------------------------------------------------+
96 function Top_Slot_Index_In (Stack : Stack_Slots) return Integer;
97 -- Index of the stack Top slot in the Slots array, denoting the latest
98 -- possible slot available to call chain leaves.
100 function Bottom_Slot_Index_In (Stack : Stack_Slots) return Integer;
101 -- Index of the stack Bottom slot in the Slots array, denoting the first
102 -- possible slot available to call chain entry points.
104 function Push_Index_Step_For (Stack : Stack_Slots) return Integer;
105 -- By how much do we need to update a Slots index to Push a single slot on
108 function Pop_Index_Step_For (Stack : Stack_Slots) return Integer;
109 -- By how much do we need to update a Slots index to Pop a single slot off
112 pragma Inline_Always (Top_Slot_Index_In);
113 pragma Inline_Always (Bottom_Slot_Index_In);
114 pragma Inline_Always (Push_Index_Step_For);
115 pragma Inline_Always (Pop_Index_Step_For);
117 -----------------------
118 -- Top_Slot_Index_In --
119 -----------------------
121 function Top_Slot_Index_In (Stack : Stack_Slots) return Integer is
123 if System.Parameters.Stack_Grows_Down then
128 end Top_Slot_Index_In;
130 ----------------------------
131 -- Bottom_Slot_Index_In --
132 ----------------------------
134 function Bottom_Slot_Index_In (Stack : Stack_Slots) return Integer is
136 if System.Parameters.Stack_Grows_Down then
141 end Bottom_Slot_Index_In;
143 -------------------------
144 -- Push_Index_Step_For --
145 -------------------------
147 function Push_Index_Step_For (Stack : Stack_Slots) return Integer is
148 pragma Unreferenced (Stack);
150 if System.Parameters.Stack_Grows_Down then
155 end Push_Index_Step_For;
157 ------------------------
158 -- Pop_Index_Step_For --
159 ------------------------
161 function Pop_Index_Step_For (Stack : Stack_Slots) return Integer is
163 return -Push_Index_Step_For (Stack);
164 end Pop_Index_Step_For;
170 -- Now the implementation of the services offered by this unit, on top of
171 -- the Stack_Slots abstraction above.
173 Index_Str : constant String := "Index";
174 Task_Name_Str : constant String := "Task Name";
175 Stack_Size_Str : constant String := "Stack Size";
176 Actual_Size_Str : constant String := "Stack usage";
178 function Get_Usage_Range (Result : Task_Result) return String;
179 -- Return string representing the range of possible result of stack usage
181 procedure Output_Result
182 (Result_Id : Natural;
183 Result : Task_Result;
184 Max_Stack_Size_Len : Natural;
185 Max_Actual_Use_Len : Natural);
186 -- Prints the result on the standard output. Result Id is the number of
187 -- the result in the array, and Result the contents of the actual result.
188 -- Max_Stack_Size_Len and Max_Actual_Use_Len are used for displaying the
189 -- proper layout. They hold the maximum length of the string representing
190 -- the Stack_Size and Actual_Use values.
196 procedure Initialize (Buffer_Size : Natural) is
197 Bottom_Of_Stack : aliased Integer;
198 Stack_Size_Chars : System.Address;
201 -- Initialize the buffered result array
203 Result_Array := new Result_Array_Type (1 .. Buffer_Size);
206 (Task_Name => (others => ASCII.NUL),
211 -- Set the Is_Enabled flag to true, so that the task wrapper knows that
212 -- it has to handle dynamic stack analysis
216 Stack_Size_Chars := System.CRTL.getenv ("GNAT_STACK_LIMIT" & ASCII.NUL);
218 -- If variable GNAT_STACK_LIMIT is set, then we will take care of the
219 -- environment task, using GNAT_STASK_LIMIT as the size of the stack.
220 -- It doesn't make sens to process the stack when no bound is set (e.g.
221 -- limit is typically up to 4 GB).
223 if Stack_Size_Chars /= Null_Address then
225 My_Stack_Size : Integer;
228 My_Stack_Size := System.CRTL.atoi (Stack_Size_Chars) * 1024;
231 (Environment_Task_Analyzer,
235 System.Storage_Elements.To_Integer (Bottom_Of_Stack'Address),
238 Fill_Stack (Environment_Task_Analyzer);
240 Compute_Environment_Task := True;
243 -- GNAT_STACK_LIMIT not set
246 Compute_Environment_Task := False;
254 procedure Fill_Stack (Analyzer : in out Stack_Analyzer) is
255 -- Change the local variables and parameters of this function with
256 -- super-extra care. The more the stack frame size of this function is
257 -- big, the more an "instrumentation threshold at writing" error is
260 Stack_Used_When_Filling : Integer;
261 Current_Stack_Level : aliased Integer;
263 Guard : constant Integer := 256;
264 -- Guard space between the Current_Stack_Level'Address and the last
265 -- allocated byte on the stack.
268 -- Easiest and most accurate method: the top of the stack is known.
270 if Analyzer.Top_Pattern_Mark /= 0 then
271 Analyzer.Pattern_Size :=
272 Stack_Size (Analyzer.Top_Pattern_Mark,
273 To_Stack_Address (Current_Stack_Level'Address))
276 if System.Parameters.Stack_Grows_Down then
277 Analyzer.Stack_Overlay_Address :=
278 To_Address (Analyzer.Top_Pattern_Mark);
280 Analyzer.Stack_Overlay_Address :=
281 To_Address (Analyzer.Top_Pattern_Mark
282 - Stack_Address (Analyzer.Pattern_Size));
286 Pattern : aliased Stack_Slots
287 (1 .. Analyzer.Pattern_Size / Bytes_Per_Pattern);
288 for Pattern'Address use Analyzer.Stack_Overlay_Address;
291 if System.Parameters.Stack_Grows_Down then
292 for J in reverse Pattern'Range loop
293 Pattern (J) := Analyzer.Pattern;
296 Analyzer.Bottom_Pattern_Mark :=
297 To_Stack_Address (Pattern (Pattern'Last)'Address);
300 for J in Pattern'Range loop
301 Pattern (J) := Analyzer.Pattern;
304 Analyzer.Bottom_Pattern_Mark :=
305 To_Stack_Address (Pattern (Pattern'First)'Address);
310 -- Readjust the pattern size. When we arrive in this function, there
311 -- is already a given amount of stack used, that we won't analyze.
313 Stack_Used_When_Filling :=
314 Stack_Size (Analyzer.Bottom_Of_Stack,
315 To_Stack_Address (Current_Stack_Level'Address));
317 if Stack_Used_When_Filling > Analyzer.Pattern_Size then
319 -- In this case, the known size of the stack is too small, we've
320 -- already taken more than expected, so there's no possible
323 Analyzer.Pattern_Size := 0;
325 Analyzer.Pattern_Size :=
326 Analyzer.Pattern_Size - Stack_Used_When_Filling;
330 Stack : aliased Stack_Slots
331 (1 .. Analyzer.Pattern_Size / Bytes_Per_Pattern);
334 Stack := (others => Analyzer.Pattern);
336 Analyzer.Stack_Overlay_Address := Stack'Address;
338 if Analyzer.Pattern_Size /= 0 then
339 Analyzer.Bottom_Pattern_Mark :=
341 (Stack (Bottom_Slot_Index_In (Stack))'Address);
342 Analyzer.Top_Pattern_Mark :=
344 (Stack (Top_Slot_Index_In (Stack))'Address);
346 Analyzer.Bottom_Pattern_Mark :=
347 To_Stack_Address (Stack'Address);
348 Analyzer.Top_Pattern_Mark :=
349 To_Stack_Address (Stack'Address);
355 -------------------------
356 -- Initialize_Analyzer --
357 -------------------------
359 procedure Initialize_Analyzer
360 (Analyzer : in out Stack_Analyzer;
362 My_Stack_Size : Natural;
363 Max_Pattern_Size : Natural;
364 Bottom : Stack_Address;
366 Pattern : Unsigned_32 := 16#DEAD_BEEF#)
369 -- Initialize the analyzer fields
371 Analyzer.Bottom_Of_Stack := Bottom;
372 Analyzer.Stack_Size := My_Stack_Size;
373 Analyzer.Pattern_Size := Max_Pattern_Size;
374 Analyzer.Pattern := Pattern;
375 Analyzer.Result_Id := Next_Id;
376 Analyzer.Task_Name := (others => ' ');
377 Analyzer.Top_Pattern_Mark := Top;
379 -- Compute the task name, and truncate if bigger than Task_Name_Length
381 if Task_Name'Length <= Task_Name_Length then
382 Analyzer.Task_Name (1 .. Task_Name'Length) := Task_Name;
384 Analyzer.Task_Name :=
385 Task_Name (Task_Name'First ..
386 Task_Name'First + Task_Name_Length - 1);
389 Next_Id := Next_Id + 1;
390 end Initialize_Analyzer;
397 (SP_Low : Stack_Address;
398 SP_High : Stack_Address) return Natural
401 if SP_Low > SP_High then
402 return Natural (SP_Low - SP_High + 4);
404 return Natural (SP_High - SP_Low + 4);
412 procedure Compute_Result (Analyzer : in out Stack_Analyzer) is
414 -- Change the local variables and parameters of this function with
415 -- super-extra care. The larger the stack frame size of this function
416 -- is, the more an "instrumentation threshold at reading" error is
419 Stack : Stack_Slots (1 .. Analyzer.Pattern_Size / Bytes_Per_Pattern);
420 for Stack'Address use Analyzer.Stack_Overlay_Address;
423 Analyzer.Topmost_Touched_Mark := Analyzer.Bottom_Pattern_Mark;
425 if Analyzer.Pattern_Size = 0 then
429 -- Look backward from the topmost possible end of the marked stack to
430 -- the bottom of it. The first index not equals to the patterns marks
431 -- the beginning of the used stack.
434 Top_Index : constant Integer := Top_Slot_Index_In (Stack);
435 Bottom_Index : constant Integer := Bottom_Slot_Index_In (Stack);
436 Step : constant Integer := Pop_Index_Step_For (Stack);
442 if Stack (J) /= Analyzer.Pattern then
443 Analyzer.Topmost_Touched_Mark
444 := To_Stack_Address (Stack (J)'Address);
448 exit when J = Bottom_Index;
454 ---------------------
455 -- Get_Usage_Range --
456 ---------------------
458 function Get_Usage_Range (Result : Task_Result) return String is
459 Variation_Used_Str : constant String :=
460 Natural'Image (Result.Variation);
461 Value_Used_Str : constant String :=
462 Natural'Image (Result.Value);
464 return Value_Used_Str & " +/- " & Variation_Used_Str;
467 ---------------------
469 ---------------------
471 procedure Output_Result
472 (Result_Id : Natural;
473 Result : Task_Result;
474 Max_Stack_Size_Len : Natural;
475 Max_Actual_Use_Len : Natural)
477 Result_Id_Str : constant String := Natural'Image (Result_Id);
478 My_Stack_Size_Str : constant String := Natural'Image (Result.Max_Size);
479 Actual_Use_Str : constant String := Get_Usage_Range (Result);
481 Result_Id_Blanks : constant
482 String (1 .. Index_Str'Length - Result_Id_Str'Length) :=
485 Stack_Size_Blanks : constant
486 String (1 .. Max_Stack_Size_Len - My_Stack_Size_Str'Length) :=
489 Actual_Use_Blanks : constant
490 String (1 .. Max_Actual_Use_Len - Actual_Use_Str'Length) :=
494 Set_Output (Standard_Error);
495 Put (Result_Id_Blanks & Natural'Image (Result_Id));
497 Put (Result.Task_Name);
499 Put (Stack_Size_Blanks & My_Stack_Size_Str);
501 Put (Actual_Use_Blanks & Actual_Use_Str);
505 ---------------------
507 ---------------------
509 procedure Output_Results is
510 Max_Stack_Size : Natural := 0;
511 Max_Actual_Use_Result_Id : Natural := Result_Array'First;
512 Max_Stack_Size_Len, Max_Actual_Use_Len : Natural := 0;
514 Task_Name_Blanks : constant
515 String (1 .. Task_Name_Length - Task_Name_Str'Length) :=
519 Set_Output (Standard_Error);
521 if Compute_Environment_Task then
522 Compute_Result (Environment_Task_Analyzer);
523 Report_Result (Environment_Task_Analyzer);
526 if Result_Array'Length > 0 then
528 -- Computes the size of the largest strings that will get displayed,
529 -- in order to do correct column alignment.
531 for J in Result_Array'Range loop
532 exit when J >= Next_Id;
534 if Result_Array (J).Value >
535 Result_Array (Max_Actual_Use_Result_Id).Value
537 Max_Actual_Use_Result_Id := J;
540 if Result_Array (J).Max_Size > Max_Stack_Size then
541 Max_Stack_Size := Result_Array (J).Max_Size;
545 Max_Stack_Size_Len := Natural'Image (Max_Stack_Size)'Length;
547 Max_Actual_Use_Len :=
548 Get_Usage_Range (Result_Array (Max_Actual_Use_Result_Id))'Length;
550 -- Display the output header. Blanks will be added in front of the
554 Stack_Size_Blanks : constant
555 String (1 .. Max_Stack_Size_Len - Stack_Size_Str'Length) :=
558 Stack_Usage_Blanks : constant
559 String (1 .. Max_Actual_Use_Len - Actual_Size_Str'Length) :=
563 if Stack_Size_Str'Length > Max_Stack_Size_Len then
564 Max_Stack_Size_Len := Stack_Size_Str'Length;
567 if Actual_Size_Str'Length > Max_Actual_Use_Len then
568 Max_Actual_Use_Len := Actual_Size_Str'Length;
572 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
573 & Stack_Size_Str & Stack_Size_Blanks & " | "
574 & Stack_Usage_Blanks & Actual_Size_Str);
579 -- Now display the individual results
581 for J in Result_Array'Range loop
582 exit when J >= Next_Id;
584 (J, Result_Array (J), Max_Stack_Size_Len, Max_Actual_Use_Len);
587 -- Case of no result stored, still display the labels
591 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
592 & Stack_Size_Str & " | " & Actual_Size_Str);
601 procedure Report_Result (Analyzer : Stack_Analyzer) is
602 Result : Task_Result :=
603 (Task_Name => Analyzer.Task_Name,
604 Max_Size => Analyzer.Stack_Size,
608 Overflow_Guard : constant Integer :=
610 - Stack_Size (Analyzer.Top_Pattern_Mark, Analyzer.Bottom_Of_Stack);
614 if Analyzer.Pattern_Size = 0 then
616 -- If we have that result, it means that we didn't do any computation
617 -- at all. In other words, we used at least everything (and possibly
620 Min := Analyzer.Stack_Size - Overflow_Guard;
621 Max := Analyzer.Stack_Size;
626 (Analyzer.Topmost_Touched_Mark, Analyzer.Bottom_Of_Stack);
627 Max := Min + Overflow_Guard;
630 Result.Value := (Max + Min) / 2;
631 Result.Variation := (Max - Min) / 2;
633 if Analyzer.Result_Id in Result_Array'Range then
635 -- If the result can be stored, then store it in Result_Array
637 Result_Array (Analyzer.Result_Id) := Result;
640 -- If the result cannot be stored, then we display it right away
643 Result_Str_Len : constant Natural :=
644 Get_Usage_Range (Result)'Length;
645 Size_Str_Len : constant Natural :=
646 Natural'Image (Analyzer.Stack_Size)'Length;
648 Max_Stack_Size_Len : Natural;
649 Max_Actual_Use_Len : Natural;
652 -- Take either the label size or the number image size for the
653 -- size of the column "Stack Size".
655 Max_Stack_Size_Len :=
656 (if Size_Str_Len > Stack_Size_Str'Length
658 else Stack_Size_Str'Length);
660 -- Take either the label size or the number image size for the
661 -- size of the column "Stack Usage".
663 Max_Actual_Use_Len :=
664 (if Result_Str_Len > Actual_Size_Str'Length
666 else Actual_Size_Str'Length);
677 end System.Stack_Usage;