Ide/Debugger/Debugger Views

Run Stack Window

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The Run Stack consists of three kinds of items:

• Continue item – marked with . It describes ordinary executable clauses, which do not produce backtrack points and are not trapped.
• BackTrack item – marked with .It describes a clause of a nondeterministic predicate. The next clause of this predicate can be executed when a program failure of this clause occurs. Such items occur when a clause of a predicate, which creates a backtrack point (can produce more than one solution) is called.
• TrapTrack item – marked with or . They describe a continue item (clause), which will be resumed in any case independently whether an error condition occurs or no. For example, such item is created when a predicate call is trapped with the trap/3 predicate. The icon is used to mark trapped clauses of deterministic predicates. The icon is used to mark trapped clauses of nondeterministic predicates.

The BackTrack (marked with ) and TrapTrack items (marked with ) are backtracking points. The clause, marked by one of these items, will be resumed and the program execution will be continued after the corresponding failure or an error occurs.

The typical example of the Run Stack window is presented in the following picture:

Pop-up Menu

The Run Stack window has the pop-up context menu:

For each selected item in the tree, this menu contains items:

• Refresh

  It refreshes all the Run Stack window contents, rebuilds the tree.

  
  It also refreshes the Variables window (if it is displayed).

• Go To Code

  Activates the Prolog source editor and places the cursor at the Prolog clause corresponding to the item selected in the Run Stack window. If the item does not correspond to a Prolog module with debug information, then the Disassembly window will be opened and the cursor will be placed onto the corresponding assembler instruction. The same action is caused by double-click a predicate call in the Run Stack window.

• Copy Line

  It copies the selected line contents to the clipboard.

• Show Domains

  This option turns ON/OFF displaying domains of variables.

• Show Values

  This option turns ON/OFF displaying values of variables.

The Run Stack window can be activated by the IDE menu View | Run Stack.

Variables Window

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The Variables window can be activated either by Ctrl+Alt+V or from the IDE menu View | Variables for Current Clause.

Variables Window Contents

The Variables window displays the tree of all program variables and facts from the traced clause, which are already created by the program at the current tracing step. These are: all variables and all object facts (fact variables), which are created in the clause before the executing instruction, and all class facts (fact variables), which can be used in this clause (declared in this class implementation).

The top line of the window displays the declaration of the predicate, whose clause is executed.

The Variables window content is updated after every trace step.

Pop-up Context Menu

The Variables in the Current Clause window has the following pop-up context menu:

This menu contains items:

• Insert into Watch Window

  Opens the Watch Window and moves there selected variable.

• Copy

  This command copies the contents of the line selected in the Variables window to the clipboard.

• Show as Hexadecimal

  Shows integral values in the hexadecimal format.

• Show as Decimal

  Shows integral values in the decimal format.

• Show as Octal

  Shows integral values in the octal format.

• Show Domains

  This option turns ON/OFF displaying the domains after variable names.

• Show Variable Addresses

  This option turns ON/OFF displaying the addresses after variable names.

• Find

  This command allows search variable by name.

• Copy Tree

  This command copies the contents of the window to the clipboard.

Facts Window

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Class Facts

The Facts window always shows the current contents of all class fact databases defined in the program being debugged.

Simple example:

Pressing CTRL+ALT+F opens Facts window:

Clicking icons opens sub-trees:

Facts window automatically goes to the fact that is selected in the text editor (if any):

Objects Facts you cat look like a components of object variables in the Variables window

Pop-up Context Menu

The Facts Window has the following pop-up context menu:

This menu contains items:

• Insert into Watch Window

  Opens the Watch Window and moves there selected fact.

• Copy

  This command copies the contents of the line selected in the Facts window to the clipboard.

• Show as Hexadecimal

  Shows integral values in the hexadecimal format.

• Show as Decimal

  Shows integral values in the decimal format.

• Show as Octal

  Shows integral values in the octal format.

• Show Domains

  This option turns ON/OFF displaying the domains after facts names.

• Show Addresses

  This option turns ON/OFF displaying the addresses after facts names.

• Find

  This command allows search fact by name.

• Copy Tree

  This command copies the contents of the window to the clipboard.

Breakpoints Window

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Introduction

The Breakpoints window shows all breakpoints, which have been set in the program being debugged.

You can set a breakpoint onto any executable line in program source files (or in the Disassembly window, where a breakpoint can be set on any instruction of the program being debugged).

There are two kinds of breakpoints: hard and soft. Hard breakpoints are active in any debugging mode. Soft breakpoints are active in normal debugging mode but disabled in a special mode of quick debugging, called Fast Forward Mode.

Breakpoints Window Contents

The Breakpoints window for each breakpoint includes Status, Source, Line, Count, Comment and Action, where:

• Status

  Shows whether the breakpoint is hard or soft.

  • Hard

    If a breakpoint is hard then it will be activated in any debugging mode. A hard breakpoint is marked with the filled circle or (for assembler) or (for relocated breakpoint).

  • Soft

    If a breakpoint is soft then it will be activated only in normal (not Fast Forward) debugging mode. A soft breakpoint is marked with the hollow circle or (for assembler).

  • Invalid

    A breakpoint is invalid when it is set on a line, which does not contain executable code. An invalid breakpoint is marked with the crossed hollow circle .

• Source

  This column shows the source string:

  SourceName

  where:

  SourceName

  The description of a predicate in the address space of whose clauses the breakpoint is set:

  • If the breakpoint is set in Prolog sources, then SourceName is the filename in which the breakpoint is set. It is displayed with the format:

  FileName '(' Path ')'

  The Path can use Build script symbols.

  • If the breakpoint is set in the Disassembly window, then SourceName has the format:

  --- assembler: AddressValue

  AddressValue is the hexadecimal address of the breakpoint in the assembler code of the predicate in which the breakpoint is set.

• Line

  When the breakpoint is set in a Prolog source file, then this column displays the number of the line the breakpoint is set on.
  When the breakpoint is set in the Disassembly window, then the number of the line is equal to 0.

• Count

  This column displays counts of breakpoints.

• Comment

  This column displays comment strings of breakpoints.

• Action

  This column displays the script text of a breakpoint. The script is performed each time the program reaches the breakpoint.

Breakpoints in Prolog and Disassembly Windows

Breakpoints can be set in Prolog source files and in the Disassembly window:

• In Prolog sources valid breakpoints can be set only on lines containing executable instructions. That is, breakpoints can be set only in predicate clauses on lines containing predicate calls, otherwise the breakpoints that are set on non-clause lines would be marked as invalid. The breakpoints that are set on clause lines that do not contain predicate calls would be shifted to the lines containing such calls (if any), but the initial line would be marked with . Valid breakpoints are marked with red circles or in Prolog sources and are shown in the Disassembly window as blue circles or . If a Prolog clause has several assembler implementations (when the clause has several flow patterns), then each breakpoint in Prolog sources can generate several breakpoints in the Disassembly window.
• Breakpoints that are set in the Disassembly window are marked with red circles or . Such breakpoint can be later overwritten by a breakpoint (marked with blue circles or ) that is set in Prolog sources on the same address as the breakpoint set in the Disassembly window.
  Notice that after modification and recompilation of the project some breakpoints that are set in the Disassembly window can be cleared (if other instructions are placed at breakpoint addresses.)

All breakpoints which are set in a program are seen in the Breakpoints window.

Breakpoint Properties

Each breakpoint has properties, which can be modified in the Breakpoint Properties dialog:

In this dialog:

The top line contains:

• If the breakpoint is set in Prolog sources, then the top line has format:

  File: FileName Line: LineNumber

  FileName is the name of the Prolog source file in which the breakpoint is set.

  LineNumber is the number of the line on which the breakpoint is set.

• If the breakpoint is set in the Disassembly window, then the top line has format:

  Breakpoint Address:Address

  Address is the breakpoint address in the program memory as it is seen in the Disassembly window.

Count Value

Shows the current number of activations of the breakpoint since its creation. The user cannot modify this value. This value increases by 1 each time when the program reaches the breakpoint.

Hard

This check box controls the Hard/Soft state of the breakpoint. When you turn a breakpoint to Hard, then it will be activated in any debugging mode. When you turn a breakpoint to Soft, then it will be activated only in normal (not Fast Forward) debugging mode.

Comment Comment string

In this edit box you can type in a Comment string. By default it has the value of the corresponding line in the source file.

Action Script text

In this box you can type in a Script text.

Note. If a module has been built without debug information (this can be done by changing /debug:full to /nodebug in the command line compiler options in the build script rules for pro->obj: and pack->obj:) then you will not be able to set a breakpoint in the Prolog sources of the module.

Notice that it does not matter in which window you remove a breakpoint (in Prolog sources, in the Breakpoints window or in the Disassembly window). In any case, removing a breakpoint deletes the breakpoint from the program.

Pop-up Menu

The Breakpoints window has the pop-up context menu:

To activate this menu, select a breakpoint and press the right mouse button. This menu contains items:

• Go to Source

  If the breakpoint is set in the Prolog sources, then the Go to Code activates the Prolog source code editor, and moves the cursor to the Prolog code corresponding to the specified breakpoint. If the breakpoint is set in the Disassembly window, then the Go to Code moves the view to this breakpoint in the Disassembly window. The same action is performed by double-click the breakpoint or by pressing the Enter on the breakpoint.

• Properties

  Invokes the Breakpoint Properties dialog for the selected breakpoint.

• Toggle (Turn to Hard/Soft)

  Switches the Hard/Soft state of the selected breakpoints.

• Delete

  Deletes the selected breakpoints.

• Turn to Hard All

  Sets the state of all breakpoints that are set in the program to Hard.

• Turn to Soft All

  Sets the state of all breakpoints that are set in the program to Soft.

• Remove All

  Removes all breakpoints that are set in the program.

The Breakpoints window is auto-updated for any breakpoint updating.

The Breakpoints window can be activated either by Ctrl+Alt+B or from the IDE menu View | Breakpoints.

Threads Window

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The Threads window shows information about the process being debugged and its threads.

The Threads window looks like following:

Names displayed in the header of the window columns are the following:

• TID

  This column displays thread identifiers of all threads created by the process being debugged.

• Current

  This column identifies the current thread by the * sign. In the Variables window you can see only variables of predicates executed in the current thread.

• State

  Displays states of threads. States can be Running, Stopped, and Suspend.

  
  Running The thread has been started, it is not suspended (see thread::suspend/0->,  syncObject::wait/0->, syncObject::wait/1->) or terminated (see thread::terminate/1).

  
  Suspend The thread is in suspended state (see thread::createSuspended/3, thread::suspend/0->, syncObject::wait/0->, syncObject::wait/1->).

  
  Stopped The thread was created and then stopped on a breakpoint, but it is not suspended (see thread::suspend/0->, syncObject::wait/0->, syncObject::wait/1->). If you set suspended state to a Stopped thread, then it turns into the Suspend state.

• Time

  Thread creation time.

• User time

  Processor time in the user-mode used by the thread.

• Kernel Time

  Processor time in the kernel-mode used by the thread.

• Priority

  The priority level of the thread. Here can be displayed the following numbers 2, 1, 0, -1, -2.

• Predicate

  This field contains the name of the currently executed thread's predicate (if it is possible to determine it).

Displayed Number	Priority Name	Description
2	Highest	The thread can be scheduled before threads with any other priority.
1	AboveNormal	The thread can be scheduled after threads with Highest priority and before those with Normal priority.
0	Normal	The thread can be scheduled after threads with AboveNormal priority and before those with BelowNormal priority. Threads have Normal priority by default.
-1	BelowNormal	The thread can be scheduled after threads with Normal priority and before those with Lowest priority.
-2	Lowest	The thread can be scheduled after threads with any other priority.

Pop-up Menu

The Threads window has the pop-up context menu. The same commands can be activated from the Thread sub-menu of the IDE task menu.

• Goto Source

  Opens the text editor and places the cursor onto the predicate, which created the selected thread.

• Set Current

  Sets the selected thread as current.

• Resume

  Resumes the run of the selected thread.

• Suspend

  Suspends the selected thread.

• Copy

  Copies the contents of the line selected in the Threads window to the clipboard.

• Copy All

  Copies the contents of the Threads window to the clipboard.

The Threads window is updated after changing any displayed parameter.

The Threads window can be activated either by CTRL+Alt+H or from the IDE menu View | Threads.

Disassembly Window

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Disassembly Window Contents

The Disassembly window shows the assembly language interpretation of the inspected code.

The disassembly starts from the specified top address toward the upper memory and prints each instruction on a new line.

Each line is printed by the pattern:

LineMarkers Address [ HexCode ] AssemblerCommand

where:

LineMarkers

Are the instruction pointer and the breakpoint (or ) markers, which can mark this line.

Address

The start address of the instruction code.

HexCode

This is the hexadecimal instruction code. This field can be shown/hidden from the pop-up menu of the Disassembly window by checking the Show OpCodes item.

AssemblerCommand

This is the assembler command corresponding to the instruction code. Assembler commands have the Intel standard assembler abbreviation. If a certain address is resolved to an external name, then this name will be printed in the command column.

The instruction, which will be executed at the next trace step, is marked with the Instruction pointer in the LineMarkers field.

Example:

Pop-up Menu

The Disassembly window has the pop-up context menu with the followin commands:

• Go To Address

  Invokes the Go to Address dialog

  

  to type in the address of the instruction, which should be displayed in the top line of the Disassembly window. The Address should be specified in the hexadecimal format. This dialog allows typing symbolic external link names and symbolic CPU register names.

• Go To EIP

  Updates the Disassembly window and places the cursor at the address of the instruction on which the program execution is suspended.

• Breakpoint…

  Allows handling the breakpoint (or ) for the assembler instruction pointed by the cursor. It has the following sub-commands:

  

  • Toggle Breakpoint

    Sets or removes a breakpoint at the instruction with the address pointed by the cursor.

  • Enable / Disable

    Enables / Disables the breakpoint pointed by the cursor. This item is disabled if there is no breakpoint at the address pointed by the cursor.

  • Properties

    Invokes the Breakpoint Properties dialog for the breakpoint pointed by the cursor. This item is disabled if there is no breakpoint at the address pointed by the cursor.

• Go To Source

  Activates the IDE source code editor and sets the cursor at the predicate whose assembler instruction is pointed by the cursor in the Disassembly window. (When it is possible.)

• Copy

  Copies lines selected in the Disassembly window to the clipboard. A selection can be performed with the Shift+Up Arrow and Shift+Down Arrow key combinations.

• Show OpCodes

  Checking and unchecking this item hides/shows hex images of operation (instruction) codes (OpCodes). These hex instruction codes are shown in the HexCode field.

• Source Annotation

  Checking OFF/ON this item hides/shows object names, corresponding to predicate entry points. Each object name is printed on a new line before the corresponding instruction line.

• Show Hints

  Shows additional information about the instruction being executed.

The Disassembly window is updated after each trace step of the debugger.

Disassembly Window Commands

• Trace Into (F11) command

  Tracing in the Disassembly window with the Step Into (F7) command performs execution of one assembler instruction (including entering into procedures if any). That is, if the Step Over command will execute a call instruction as one trace step, then the Step Into command will go into the called procedure. It usually executes disassembler instructions line after line.

• Step Over (F10) command

  Tracing in the Disassembly window with the Step Over (F10) command performs execution of one assembler instruction (including execution of call instructions). So the Step Over (F10) command works almost the same way as the Trace Into (F11) command except for execution of call instructions. In difference to the Trace Into (F11) command, it tries to perform call instructions as one step and reaches the next line only if the called code returns to that line.

• Run to Cursor (CTRL+F10) command

  Tracing in the Disassembly window with the Run to Cursor (CTRL+F10) command works in the following way. The debugger places an invisible breakpoint at the address corresponding to the instruction specified by the cursor and performs the Debug Run (F5) command. It depends only upon the program code whether the program will reach this instruction or will never reach it.

The Disassembly window can be activated:

• by Shift+Alt+1
• by Ctrl+D from the traceable source code. The topmost line of the Disassembly window displays the address of the disassembler instruction corresponding to the predicate pointed by the cursor in the source code.
• from the IDE menu View | Disassembly

If the tracing code has no debug information, then the Disassembly window is opened initially (when the debugger starts) and the instruction pointer points to the executing assembler instruction.

Registers Window

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The Registers window shows current values of the CPU (Central Processor Unit) registers:

• General registers
• Segment registers
• Flags
• Floating-point registers

A register value is printed:

• red, if it is changed from the last program trace step
• blue, otherwise.

For example:

The Floating Point command from context pop-up menu can be used to turn ON/OFF the displaying of Floating-point registers.

The Registers window can be activated either by Ctr+ Alt+G or from the IDE menu View | Registers.

Modules Window

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The Modules Window shows all the modules currently loaded in this debug session. It shows the filename, path, the base address range, the code address range and the type of debug information.

Memory Dump Window

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The Memory Dump window shows the virtual memory dump of the program being debugged. Memory dump lines have the length, which is determined by the window width. The number of printed lines window height.

Information Displayed in the Memory Dump Window

Each line in the Memory Dump window is printed by the pattern:

Address | [ HexValues ] [ ASCIIcharacters ] [ UnicodeCharacters]

where:

Address

This is the hexadecimal address of the first byte of the memory displayed in this line.

HexValues

HexValues : HexValue [ HexValues ]

This is the hexadecimal format of the memory dump. Each hex value can be an image of one, two, four or eight continued memory bytes (this is contolled by the Memory Dump window content pop-up menu).

ASCIIcharacters

ASCIIcharacters : ASCIIcharacter [ ASCIIcharacters ]

This is the same memory dump but in the format of ASCII characters (a character represenrs one byte). Unprintable characters are printed as dots.

UnicodeCharacters

UnicodeCharacters : UnicodeCharacter [ UnicodeCharacters ]

This is the same memory dump in the format of Unicode characters (a character represents two bytes). Unprintable characters are printed as dots.

Example:

The Memory Dump window title shows the module name, which memory is displayed in the window. If the module name cannot be determined, then the title displays Unknown module.

Content Pop-up Menu

The Memory Dump window has the pop-up context menu which contains commands:

• Go To Address

  Ctrl+G. Invokes the Go to Address dialog

  

  to type a new top address in hex format. This dialog allows typing symbolic external link names and symbolic CPU register names. Double-click in the Memory Dump window area also activates the Go to Address dialog.

• Go To Ptr

  Ctrl+Shift+G. Updates the Memory Dump window starting the first line from the address shown as Ptr (address defined by the memory contents of four or eight continued bytes at which the cursor is pointing if one of 4-byte Integer or 8-byte Integer is selected).

• Undo Go to

  Alt+Left Arrow. Updates the Memory Dump window view to start from the previously used top (the first line) address.

• Redo Go to

  Alt+Right Arrow. This operation is the counterpart to the Undo Go to. It updates the Memory Dump window view to start from the "next" top address, which was used before the Undo Go to command was implemented.

• Set Memory Breakpoint

  This operation sets a memory breakpoint at address from the left pane.

• Remove Memory Breakpoint

  This operation removes a previously set a memory breakpoint.

• Copy

  Copies the selected lines to the clipboard. To select a line, click on it while holding the shift key. You can select multiple lines at one time.

• Copy Ptr

  Ctrl+C. Copies hexadecimal representation of the specified address (four or eight bytes) to the clipboard.

• Refresh

  Refresh the Memory Dump window contents.

• Write Block

  This command opens the Write Memory Block dialog:

  

  • Filename

    Here you should type in the name of a file in which the specified memory block should be saved.

  • Start Address

    Here you should specify a hexadecimal start address of the memory block.

  • Length

    Here you should specify a hexadecimal length in bytes of the memory block.

• Show Hex

  Shows the column, which displays the memory dump in the hexadecimal format. This is the HexValues column in the right pane.

• Show ASCII

  Shows the column, which displays the ASCII format of the memory dump. This is the ASCIIcharacters column in the right pane.

• Show Unicode

  Shows the column, which displays the Unicode format of the memory dump. This is the UnicodeCharacters column in the right pane.

• Update Speed...

  Defines the rate of the Memory Dump window updating:

  

  • High

    Performs automatic updating with the high rate.

  • Normal

    Performs automatic updating with normal rate.

  • Low

    Performs automatic updating with low rate.

  • Manual

    No automatic updating.

The Memory Dump window can be activated either by CTRL+Alt+M or from the IDE menu View | Memory Dump.