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) 2004-2008, 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 2, or (at your option) any later ver- --
14 -- sion. GNARL 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 with System.Parameters;
38 package body System.Stack_Usage is
39 use System.Storage_Elements;
48 -- Stackl_Slots is an internal data type to represent a sequence of real
49 -- stack slots initialized with a provided pattern, with operations to
50 -- abstract away the target call stack growth direction.
52 type Stack_Slots is array (Integer range <>) of Pattern_Type;
53 for Stack_Slots'Component_Size use Pattern_Type'Object_Size;
55 -- We will carefully handle the initializations ourselves and might want
56 -- to remap an initialized overlay later on with an address clause.
58 pragma Suppress_Initialization (Stack_Slots);
60 -- The abstract Stack_Slots operations all operate over the simple array
63 -- memory addresses increasing ---->
65 -- Slots('First) Slots('Last)
68 -- +------------------------------------------------------------------+
70 -- +------------------------------------------------------------------+
72 -- What we call Top or Bottom always denotes call chain leaves or entry
73 -- points respectively, and their relative positions in the stack array
74 -- depends on the target stack growth direction:
78 -- <----- calls push frames towards decreasing addresses
80 -- Top(most) Slot Bottom(most) Slot
83 -- +------------------------------------------------------------------+
84 -- |####| | leaf frame | ... | entry frame |
85 -- +------------------------------------------------------------------+
89 -- calls push frames towards increasing addresses ----->
91 -- Bottom(most) Slot Top(most) Slot
94 -- +------------------------------------------------------------------+
95 -- | entry frame | ... | leaf frame | |####|
96 -- +------------------------------------------------------------------+
98 function Top_Slot_Index_In (Stack : Stack_Slots) return Integer;
99 -- Index of the stack Top slot in the Slots array, denoting the latest
100 -- possible slot available to call chain leaves.
102 function Bottom_Slot_Index_In (Stack : Stack_Slots) return Integer;
103 -- Index of the stack Bottom slot in the Slots array, denoting the first
104 -- possible slot available to call chain entry points.
106 function Push_Index_Step_For (Stack : Stack_Slots) return Integer;
107 -- By how much do we need to update a Slots index to Push a single slot on
110 function Pop_Index_Step_For (Stack : Stack_Slots) return Integer;
111 -- By how much do we need to update a Slots index to Pop a single slot off
114 pragma Inline_Always (Top_Slot_Index_In);
115 pragma Inline_Always (Bottom_Slot_Index_In);
116 pragma Inline_Always (Push_Index_Step_For);
117 pragma Inline_Always (Pop_Index_Step_For);
119 -----------------------
120 -- Top_Slot_Index_In --
121 -----------------------
123 function Top_Slot_Index_In (Stack : Stack_Slots) return Integer is
125 if System.Parameters.Stack_Grows_Down then
130 end Top_Slot_Index_In;
132 ----------------------------
133 -- Bottom_Slot_Index_In --
134 ----------------------------
136 function Bottom_Slot_Index_In (Stack : Stack_Slots) return Integer is
138 if System.Parameters.Stack_Grows_Down then
143 end Bottom_Slot_Index_In;
145 -------------------------
146 -- Push_Index_Step_For --
147 -------------------------
149 function Push_Index_Step_For (Stack : Stack_Slots) return Integer is
150 pragma Unreferenced (Stack);
152 if System.Parameters.Stack_Grows_Down then
157 end Push_Index_Step_For;
159 ------------------------
160 -- Pop_Index_Step_For --
161 ------------------------
163 function Pop_Index_Step_For (Stack : Stack_Slots) return Integer is
165 return -Push_Index_Step_For (Stack);
166 end Pop_Index_Step_For;
172 -- Now the implementation of the services offered by this unit, on top of
173 -- the Stack_Slots abstraction above.
175 Index_Str : constant String := "Index";
176 Task_Name_Str : constant String := "Task Name";
177 Stack_Size_Str : constant String := "Stack Size";
178 Actual_Size_Str : constant String := "Stack usage [min - max]";
180 function Get_Usage_Range (Result : Task_Result) return String;
181 -- Return string representing the range of possible result of stack usage
183 procedure Output_Result
184 (Result_Id : Natural;
185 Result : Task_Result;
186 Max_Stack_Size_Len : Natural;
187 Max_Actual_Use_Len : Natural);
188 -- Prints the result on the standard output. Result Id is the number of
189 -- the result in the array, and Result the contents of the actual result.
190 -- Max_Stack_Size_Len and Max_Actual_Use_Len are used for displaying the
191 -- proper layout. They hold the maximum length of the string representing
192 -- the Stack_Size and Actual_Use values.
198 procedure Initialize (Buffer_Size : Natural) is
199 Bottom_Of_Stack : aliased Integer;
200 Stack_Size_Chars : System.Address;
203 -- Initialize the buffered result array
205 Result_Array := new Result_Array_Type (1 .. Buffer_Size);
208 (Task_Name => (others => ASCII.NUL),
213 -- Set the Is_Enabled flag to true, so that the task wrapper knows that
214 -- it has to handle dynamic stack analysis
218 Stack_Size_Chars := System.CRTL.getenv ("GNAT_STACK_LIMIT" & ASCII.NUL);
220 -- If variable GNAT_STACK_LIMIT is set, then we will take care of the
221 -- environment task, using GNAT_STASK_LIMIT as the size of the stack.
222 -- It doesn't make sens to process the stack when no bound is set (e.g.
223 -- limit is typically up to 4 GB).
225 if Stack_Size_Chars /= Null_Address then
227 Stack_Size : Integer;
230 Stack_Size := System.CRTL.atoi (Stack_Size_Chars) * 1024;
233 (Environment_Task_Analyzer,
237 System.Storage_Elements.To_Integer (Bottom_Of_Stack'Address));
239 Fill_Stack (Environment_Task_Analyzer);
241 Compute_Environment_Task := True;
244 -- GNAT_STACK_LIMIT not set
247 Compute_Environment_Task := False;
255 procedure Fill_Stack (Analyzer : in out Stack_Analyzer) is
256 -- Change the local variables and parameters of this function with
257 -- super-extra care. The more the stack frame size of this function is
258 -- big, the more an "instrumentation threshold at writing" error is
261 Current_Stack_Level : aliased Integer;
263 -- Reajust the pattern size. When we arrive in this function, there is
264 -- already a given amount of stack used, that we won't analyze.
266 Analyzer.Stack_Used_When_Filling := Stack_Size
267 (Analyzer.Bottom_Of_Stack,
268 To_Stack_Address (Current_Stack_Level'Address))
269 + Natural (Current_Stack_Level'Size);
271 Analyzer.Pattern_Size := Analyzer.Pattern_Size
272 - Analyzer.Stack_Used_When_Filling;
275 Stack : aliased Stack_Slots
276 (1 .. Analyzer.Pattern_Size / Bytes_Per_Pattern);
278 Stack := (others => Analyzer.Pattern);
280 Analyzer.Stack_Overlay_Address := Stack'Address;
282 Analyzer.Bottom_Pattern_Mark :=
283 To_Stack_Address (Stack (Bottom_Slot_Index_In (Stack))'Address);
284 Analyzer.Top_Pattern_Mark :=
285 To_Stack_Address (Stack (Top_Slot_Index_In (Stack))'Address);
287 -- If Arr has been packed, the following assertion must be true (we
288 -- add the size of the element whose address is:
289 -- Min (Analyzer.Inner_Pattern_Mark, Analyzer.Outer_Pattern_Mark)):
292 (Analyzer.Pattern_Size =
294 (Analyzer.Top_Pattern_Mark, Analyzer.Bottom_Pattern_Mark));
298 -------------------------
299 -- Initialize_Analyzer --
300 -------------------------
302 procedure Initialize_Analyzer
303 (Analyzer : in out Stack_Analyzer;
305 Stack_Size : Natural;
306 Max_Pattern_Size : Natural;
307 Bottom : Stack_Address;
308 Pattern : Unsigned_32 := 16#DEAD_BEEF#)
311 -- Initialize the analyzer fields
313 Analyzer.Bottom_Of_Stack := Bottom;
314 Analyzer.Stack_Size := Stack_Size;
315 Analyzer.Pattern_Size := Max_Pattern_Size;
316 Analyzer.Pattern := Pattern;
317 Analyzer.Result_Id := Next_Id;
319 Analyzer.Task_Name := (others => ' ');
321 -- Compute the task name, and truncate it if it's bigger than
324 if Task_Name'Length <= Task_Name_Length then
325 Analyzer.Task_Name (1 .. Task_Name'Length) := Task_Name;
327 Analyzer.Task_Name :=
328 Task_Name (Task_Name'First ..
329 Task_Name'First + Task_Name_Length - 1);
332 Next_Id := Next_Id + 1;
333 end Initialize_Analyzer;
340 (SP_Low : Stack_Address;
341 SP_High : Stack_Address) return Natural
344 if SP_Low > SP_High then
345 return Natural (SP_Low - SP_High + 4);
347 return Natural (SP_High - SP_Low + 4);
355 procedure Compute_Result (Analyzer : in out Stack_Analyzer) is
357 -- Change the local variables and parameters of this function with
358 -- super-extra care. The larger the stack frame size of this function
359 -- is, the more an "instrumentation threshold at reading" error is
362 Stack : Stack_Slots (1 .. Analyzer.Pattern_Size / Bytes_Per_Pattern);
363 for Stack'Address use Analyzer.Stack_Overlay_Address;
366 Analyzer.Topmost_Touched_Mark := Analyzer.Bottom_Pattern_Mark;
368 -- Look backward from the topmost possible end of the marked stack to
369 -- the bottom of it. The first index not equals to the patterns marks
370 -- the beginning of the used stack.
373 Top_Index : constant Integer := Top_Slot_Index_In (Stack);
374 Bottom_Index : constant Integer := Bottom_Slot_Index_In (Stack);
375 Step : constant Integer := Pop_Index_Step_For (Stack);
381 if Stack (J) /= Analyzer.Pattern then
382 Analyzer.Topmost_Touched_Mark
383 := To_Stack_Address (Stack (J)'Address);
387 exit when J = Bottom_Index;
393 ---------------------
394 -- Get_Usage_Range --
395 ---------------------
397 function Get_Usage_Range (Result : Task_Result) return String is
398 Min_Used_Str : constant String := Natural'Image (Result.Min_Measure);
399 Max_Used_Str : constant String := Natural'Image (Result.Max_Measure);
401 return "[" & Min_Used_Str (2 .. Min_Used_Str'Last) & " -"
402 & Max_Used_Str & "]";
405 ---------------------
407 ---------------------
409 procedure Output_Result
410 (Result_Id : Natural;
411 Result : Task_Result;
412 Max_Stack_Size_Len : Natural;
413 Max_Actual_Use_Len : Natural)
415 Result_Id_Str : constant String := Natural'Image (Result_Id);
416 Stack_Size_Str : constant String := Natural'Image (Result.Max_Size);
417 Actual_Use_Str : constant String := Get_Usage_Range (Result);
419 Result_Id_Blanks : constant
420 String (1 .. Index_Str'Length - Result_Id_Str'Length) :=
423 Stack_Size_Blanks : constant
424 String (1 .. Max_Stack_Size_Len - Stack_Size_Str'Length) :=
427 Actual_Use_Blanks : constant
428 String (1 .. Max_Actual_Use_Len - Actual_Use_Str'Length) :=
432 Set_Output (Standard_Error);
433 Put (Result_Id_Blanks & Natural'Image (Result_Id));
435 Put (Result.Task_Name);
437 Put (Stack_Size_Blanks & Stack_Size_Str);
439 Put (Actual_Use_Blanks & Actual_Use_Str);
443 ---------------------
445 ---------------------
447 procedure Output_Results is
448 Max_Stack_Size : Natural := 0;
449 Max_Actual_Use_Result_Id : Natural := Result_Array'First;
450 Max_Stack_Size_Len, Max_Actual_Use_Len : Natural := 0;
452 Task_Name_Blanks : constant
453 String (1 .. Task_Name_Length - Task_Name_Str'Length) :=
457 Set_Output (Standard_Error);
459 if Compute_Environment_Task then
460 Compute_Result (Environment_Task_Analyzer);
461 Report_Result (Environment_Task_Analyzer);
464 if Result_Array'Length > 0 then
466 -- Computes the size of the largest strings that will get displayed,
467 -- in order to do correct column alignment.
469 for J in Result_Array'Range loop
470 exit when J >= Next_Id;
472 if Result_Array (J).Max_Measure
473 > Result_Array (Max_Actual_Use_Result_Id).Max_Measure
475 Max_Actual_Use_Result_Id := J;
478 if Result_Array (J).Max_Size > Max_Stack_Size then
479 Max_Stack_Size := Result_Array (J).Max_Size;
483 Max_Stack_Size_Len := Natural'Image (Max_Stack_Size)'Length;
485 Max_Actual_Use_Len :=
486 Get_Usage_Range (Result_Array (Max_Actual_Use_Result_Id))'Length;
488 -- Display the output header. Blanks will be added in front of the
492 Stack_Size_Blanks : constant
493 String (1 .. Max_Stack_Size_Len - Stack_Size_Str'Length) :=
496 Stack_Usage_Blanks : constant
497 String (1 .. Max_Actual_Use_Len - Actual_Size_Str'Length) :=
501 if Stack_Size_Str'Length > Max_Stack_Size_Len then
502 Max_Stack_Size_Len := Stack_Size_Str'Length;
505 if Actual_Size_Str'Length > Max_Actual_Use_Len then
506 Max_Actual_Use_Len := Actual_Size_Str'Length;
510 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
511 & Stack_Size_Str & Stack_Size_Blanks & " | "
512 & Stack_Usage_Blanks & Actual_Size_Str);
517 -- Now display the individual results
519 for J in Result_Array'Range loop
520 exit when J >= Next_Id;
522 (J, Result_Array (J), Max_Stack_Size_Len, Max_Actual_Use_Len);
525 -- Case of no result stored, still display the labels
529 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
530 & Stack_Size_Str & " | " & Actual_Size_Str);
539 procedure Report_Result (Analyzer : Stack_Analyzer) is
540 Measure : constant Natural :=
542 (Analyzer.Topmost_Touched_Mark,
543 Analyzer.Bottom_Of_Stack)
544 + Analyzer.Stack_Used_When_Filling;
545 Result : constant Task_Result :=
546 (Task_Name => Analyzer.Task_Name,
547 Max_Size => Analyzer.Stack_Size,
548 Min_Measure => Measure,
549 Max_Measure => Measure + Analyzer.Stack_Size
550 - Analyzer.Pattern_Size);
552 if Analyzer.Result_Id in Result_Array'Range then
554 -- If the result can be stored, then store it in Result_Array
556 Result_Array (Analyzer.Result_Id) := Result;
559 -- If the result cannot be stored, then we display it right away
562 Result_Str_Len : constant Natural :=
563 Get_Usage_Range (Result)'Length;
564 Size_Str_Len : constant Natural :=
565 Natural'Image (Analyzer.Stack_Size)'Length;
567 Max_Stack_Size_Len : Natural;
568 Max_Actual_Use_Len : Natural;
571 -- Take either the label size or the number image size for the
572 -- size of the column "Stack Size".
574 if Size_Str_Len > Stack_Size_Str'Length then
575 Max_Stack_Size_Len := Size_Str_Len;
577 Max_Stack_Size_Len := Stack_Size_Str'Length;
580 -- Take either the label size or the number image size for the
581 -- size of the column "Stack Usage"
583 if Result_Str_Len > Actual_Size_Str'Length then
584 Max_Actual_Use_Len := Result_Str_Len;
586 Max_Actual_Use_Len := Actual_Size_Str'Length;
598 end System.Stack_Usage;