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) 2004-2007, 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),
211 Overflow_Guard => 0));
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 doens'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
257 -- Change the local variables and parameters of this function with
258 -- super-extra care. The more the stack frame size of this function is
259 -- big, the more an "instrumentation threshold at writing" error is
262 Stack : aliased Stack_Slots (1 .. Analyzer.Size / Bytes_Per_Pattern);
265 Stack := (others => Analyzer.Pattern);
267 Analyzer.Stack_Overlay_Address := Stack'Address;
269 Analyzer.Bottom_Pattern_Mark :=
270 To_Stack_Address (Stack (Bottom_Slot_Index_In (Stack))'Address);
271 Analyzer.Top_Pattern_Mark :=
272 To_Stack_Address (Stack (Top_Slot_Index_In (Stack))'Address);
274 -- If Arr has been packed, the following assertion must be true (we add
275 -- the size of the element whose address is:
276 -- Min (Analyzer.Inner_Pattern_Mark, Analyzer.Outer_Pattern_Mark)):
281 (Analyzer.Top_Pattern_Mark, Analyzer.Bottom_Pattern_Mark));
284 -------------------------
285 -- Initialize_Analyzer --
286 -------------------------
288 procedure Initialize_Analyzer
289 (Analyzer : in out Stack_Analyzer;
292 Overflow_Guard : Natural;
293 Bottom : Stack_Address;
294 Pattern : Unsigned_32 := 16#DEAD_BEEF#)
297 -- Initialize the analyzer fields
299 Analyzer.Bottom_Of_Stack := Bottom;
300 Analyzer.Size := Size;
301 Analyzer.Pattern := Pattern;
302 Analyzer.Result_Id := Next_Id;
304 Analyzer.Task_Name := (others => ' ');
306 -- Compute the task name, and truncate it if it's bigger than
309 if Task_Name'Length <= Task_Name_Length then
310 Analyzer.Task_Name (1 .. Task_Name'Length) := Task_Name;
312 Analyzer.Task_Name :=
313 Task_Name (Task_Name'First ..
314 Task_Name'First + Task_Name_Length - 1);
317 Analyzer.Overflow_Guard := Overflow_Guard;
319 Next_Id := Next_Id + 1;
320 end Initialize_Analyzer;
327 (SP_Low : Stack_Address;
328 SP_High : Stack_Address) return Natural
331 if SP_Low > SP_High then
332 return Natural (SP_Low - SP_High + 4);
334 return Natural (SP_High - SP_Low + 4);
342 procedure Compute_Result (Analyzer : in out Stack_Analyzer) is
344 -- Change the local variables and parameters of this function with
345 -- super-extra care. The larger the stack frame size of this function
346 -- is, the more an "instrumentation threshold at reading" error is
349 Stack : Stack_Slots (1 .. Analyzer.Size / Bytes_Per_Pattern);
350 for Stack'Address use Analyzer.Stack_Overlay_Address;
353 Analyzer.Topmost_Touched_Mark := Analyzer.Bottom_Pattern_Mark;
355 -- Look backward from the topmost possible end of the marked stack to
356 -- the bottom of it. The first index not equals to the patterns marks
357 -- the beginning of the used stack.
360 Top_Index : constant Integer := Top_Slot_Index_In (Stack);
361 Bottom_Index : constant Integer := Bottom_Slot_Index_In (Stack);
362 Step : constant Integer := Pop_Index_Step_For (Stack);
368 if Stack (J) /= Analyzer.Pattern then
369 Analyzer.Topmost_Touched_Mark
370 := To_Stack_Address (Stack (J)'Address);
374 exit when J = Bottom_Index;
380 ---------------------
381 -- Get_Usage_Range --
382 ---------------------
384 function Get_Usage_Range (Result : Task_Result) return String is
385 Min_Used_Str : constant String :=
386 Natural'Image (Result.Measure);
387 Max_Used_Str : constant String :=
388 Natural'Image (Result.Measure + Result.Overflow_Guard);
390 return "[" & Min_Used_Str (2 .. Min_Used_Str'Last) & " -"
391 & Max_Used_Str & "]";
394 ---------------------
396 ---------------------
398 procedure Output_Result
399 (Result_Id : Natural;
400 Result : Task_Result;
401 Max_Stack_Size_Len : Natural;
402 Max_Actual_Use_Len : Natural)
404 Result_Id_Str : constant String := Natural'Image (Result_Id);
405 Stack_Size_Str : constant String := Natural'Image (Result.Max_Size);
406 Actual_Use_Str : constant String := Get_Usage_Range (Result);
408 Result_Id_Blanks : constant
409 String (1 .. Index_Str'Length - Result_Id_Str'Length) :=
412 Stack_Size_Blanks : constant
413 String (1 .. Max_Stack_Size_Len - Stack_Size_Str'Length) :=
416 Actual_Use_Blanks : constant
417 String (1 .. Max_Actual_Use_Len - Actual_Use_Str'Length) :=
421 Set_Output (Standard_Error);
422 Put (Result_Id_Blanks & Natural'Image (Result_Id));
424 Put (Result.Task_Name);
426 Put (Stack_Size_Blanks & Stack_Size_Str);
428 Put (Actual_Use_Blanks & Actual_Use_Str);
432 ---------------------
434 ---------------------
436 procedure Output_Results is
437 Max_Stack_Size : Natural := 0;
438 Max_Actual_Use_Result_Id : Natural := Result_Array'First;
439 Max_Stack_Size_Len, Max_Actual_Use_Len : Natural := 0;
441 Task_Name_Blanks : constant
442 String (1 .. Task_Name_Length - Task_Name_Str'Length) :=
446 Set_Output (Standard_Error);
448 if Compute_Environment_Task then
449 Compute_Result (Environment_Task_Analyzer);
450 Report_Result (Environment_Task_Analyzer);
453 if Result_Array'Length > 0 then
455 -- Computes the size of the largest strings that will get displayed,
456 -- in order to do correct column alignment.
458 for J in Result_Array'Range loop
459 exit when J >= Next_Id;
461 if Result_Array (J).Measure
462 > Result_Array (Max_Actual_Use_Result_Id).Measure
464 Max_Actual_Use_Result_Id := J;
467 if Result_Array (J).Max_Size > Max_Stack_Size then
468 Max_Stack_Size := Result_Array (J).Max_Size;
472 Max_Stack_Size_Len := Natural'Image (Max_Stack_Size)'Length;
474 Max_Actual_Use_Len :=
475 Get_Usage_Range (Result_Array (Max_Actual_Use_Result_Id))'Length;
477 -- Display the output header. Blanks will be added in front of the
481 Stack_Size_Blanks : constant
482 String (1 .. Max_Stack_Size_Len - Stack_Size_Str'Length) :=
485 Stack_Usage_Blanks : constant
486 String (1 .. Max_Actual_Use_Len - Actual_Size_Str'Length) :=
490 if Stack_Size_Str'Length > Max_Stack_Size_Len then
491 Max_Stack_Size_Len := Stack_Size_Str'Length;
494 if Actual_Size_Str'Length > Max_Actual_Use_Len then
495 Max_Actual_Use_Len := Actual_Size_Str'Length;
499 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
500 & Stack_Size_Str & Stack_Size_Blanks & " | "
501 & Stack_Usage_Blanks & Actual_Size_Str);
506 -- Now display the individual results
508 for J in Result_Array'Range loop
509 exit when J >= Next_Id;
511 (J, Result_Array (J), Max_Stack_Size_Len, Max_Actual_Use_Len);
514 -- Case of no result stored, still display the labels
518 (Index_Str & " | " & Task_Name_Str & Task_Name_Blanks & " | "
519 & Stack_Size_Str & " | " & Actual_Size_Str);
528 procedure Report_Result (Analyzer : Stack_Analyzer) is
529 Result : constant Task_Result :=
530 (Task_Name => Analyzer.Task_Name,
531 Max_Size => Analyzer.Size + Analyzer.Overflow_Guard,
532 Measure => Stack_Size
533 (Analyzer.Topmost_Touched_Mark,
534 Analyzer.Bottom_Of_Stack),
535 Overflow_Guard => Analyzer.Overflow_Guard -
536 Natural (Analyzer.Bottom_Of_Stack -
537 Analyzer.Bottom_Pattern_Mark));
540 if Analyzer.Result_Id in Result_Array'Range then
542 -- If the result can be stored, then store it in Result_Array
544 Result_Array (Analyzer.Result_Id) := Result;
547 -- If the result cannot be stored, then we display it right away
550 Result_Str_Len : constant Natural :=
551 Get_Usage_Range (Result)'Length;
552 Size_Str_Len : constant Natural :=
553 Natural'Image (Analyzer.Size)'Length;
555 Max_Stack_Size_Len : Natural;
556 Max_Actual_Use_Len : Natural;
559 -- Take either the label size or the number image size for the
560 -- size of the column "Stack Size".
562 if Size_Str_Len > Stack_Size_Str'Length then
563 Max_Stack_Size_Len := Size_Str_Len;
565 Max_Stack_Size_Len := Stack_Size_Str'Length;
568 -- Take either the label size or the number image size for the
569 -- size of the column "Stack Usage"
571 if Result_Str_Len > Actual_Size_Str'Length then
572 Max_Actual_Use_Len := Result_Str_Len;
574 Max_Actual_Use_Len := Actual_Size_Str'Length;
586 end System.Stack_Usage;