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Memory Validator Help

The Query tab shows groups of search results and allows you to find many types of related data for different memory allocations.

 

interactiveClick a part of the image below to jump straight to the help for that area.

 

analysis-tab1

 

 

If you've read the previous sections then you'll probably have seen menu options referring to showing results here on the analysis tab.

 

Think of the analysis tab as a basket where you can send groups of data to inspect at your leisure.

 

That data will appear in the upper of the two resizable windows and becomes your working data from which you can also find related allocations to display in the lower window.

 

 

The Analysis Data

 

Both the upper and lower views show data in the same format as that found in the Memory tab's collected data.

 

Each line has an icon at the left, indicating its type, and has an explanatory tooltip:

 

allocation-type-symbol-tooltips

 

The text on each line is the same and indicates:

 

datatype (if known)

size

allocation address/handle value

source file and line number (if available) where the allocation occurred

an optional event sequence id at the beginning of the line

 

The background colour for each line indicates the status of the data - eg, leaked, damaged, or uninitialized.

 

To edit the source code, double click on any part of the lines of source code displayed or use right_mouse_buttonEdit Source Code...

 

 

The upper window - working data

 

The upper window will contain any data sent from other tabs or results of queries made via the buttons at the left.

 

This becomes your working data, and will grow (with a header line between each group) as each set of results is added.

 

Using the relations option on the popup menu, you can then find related allocations or objects which are displayed as separate results in the lower window.

 

 

The lower window - results within results

 

Having obtained related data in the lower window you can inspect it in the same way, filter it and promote it back up to the top window.

 

 

Analysis tab options - upper window

 

At the far left of the window are the now familiar options for filtering data using the the Watermark and Tracker methods outlined for the Memory tab.

 

analysis-filter-options

 

Also familiar, are the filter and display settings:

 

Filter... instructionStep shows the local filters dialog for the memory tab

 

 The filter button also indicates the number of local filters, although not all of these may be enabled
 

num-local-filters

 

Display... instructionStep shows the Analysis Display Settings dialog

 

Unlike other tabs, there are no options to update the display here, since the data is always static.

 

Instead, there are options to change the type of memory allocation you are interested in, and these will only take effect on any new queries added to the display.

 

analysis-filter-options1

 

 

Behaviour instructionStep choose to show memory that has reached one or all of the allocation, reallocation and deallocation stages

 

Type instructionStep choose to show query results for handles, or memory as per the above behaviour, or both

 

 

Clear Results instructionStep removes all working data from the upper window only as the lower window has its own clear button

 

 

Running data queries

 

The data in the analysis tab is not limited to that sent from other tabs.

 

From the buttons at the left you can run some common or very targeted queries to search for allocations, reallocations, and deallocations of memory and resource handles.

 

 

Custom queries

 

Several of the main tabs have some comprehensive methods of querying memory or functions, and which are accessible from the main query menu and query toolbar.

 

The Analysis tab has dedicated buttons for two of these queries:

 

Memory... instructionStep Shows the Find Memory dialog to use a wide range of search criteria to find memory
 

Functions... instructionStep Shows the Find Functions dialog but displays the results here in the analysis tab
 

 

Predefined queries

 

There are a selection of common predefined queries available at a single click:

 

analysis-predefined-queries

 

Damaged instructionStep finds all damaged memory allocations, such as overwrite, underwrite, double delete, etc
 

Uninitialised instructionStep shows any detected uninitialised memory if you've switched these hooks and settings on

 

Leaked instructionStep finds all leaked locations, memory and handles still in use after the application has exited

 

Invalid Handles instructionStep finds all invalid or NULL handles

 

Trace Messages instructionStep shows any trace messages if you've switched the trace hook setting on

 

 

Memory reuse

 

Memory re-use is not necessarily an error, in fact it almost certainly isn't, as the allocator will provide previously freed memory addresses as memory allocation addresses.

 

For certain bugs, memory corruption being an example, you may be interested in knowing which locations allocated memory allocations at a particular address,

and if that address has been re-used. These are targets for further investigation.

 

Memory Reuse instructionStep searches for reused memory in the application

 

analysis-memory-reuse

 

Because search through all memory may take a long time in a large and active application, you can instead opt to search within a range of memory:

 

The start and end addresses for the memory range can be entered in decimal or hexadecimal format with the leading 0x

 

note Note that some libraries outside your control may reuse memory, so be aware that not all results found are necessarily errors in your application.

 

 

Analysis tab options - lower window

 

The lower window has it's own comparatively simple set of options:

 

analysis-lower-options

 

Auto Clear instructionStep clears the lower window before adding a new relations search from the upper window

 

Clear when Promote instructionStep clears the lower window when promoting these results to the upper window

 

Clear Results instructionStep simply empties the lower window
 

 

Filter Results instructionStep optionally filters the lower window data using the same filters as the upper window

 

Use Watermarks on Results instructionStep applies the upper window's watermark settings to the lower window

 

Include search in results instructionStep brings the upper window item that initiated the relations search along with the results
 
 

Promote Results instructionStep pushes all or selected lower window results into the upper window, optionally adding to or replacing what's there already
 
 

 

Analysis view popup menuright_mouse_button

 

interactiveThe following popup menu is available over the upper window.

 

analysis-menu2

 

 

 

right_mouse_buttonMenu option: data item summary

 

Help on selected item instructionStep the sub-menu shows a simple one line description of the selected entry:

 

memory-menu-item-help

 

 

right_mouse_buttonMenu option: relations

 

The relations menu has a large sub-menu with many different options for choosing a set of related data to display in the lower analysis window.

 

Think of this as a sub-query on the working data - like searching for friends of friends on a social network!

 

Given an entry in the upper window, available relations are as follows, with allocations generally meaning any allocation, reallocation or deallocation

 

Same address

Same size

Smaller

Larger

Finds any other allocations on the same memory address, for example previous allocations or frees

Allocations on any memory objects of identical size

  or on smaller

  or larger objects

Same handle

Finds any other allocations of the same resource handle

Same object/handle type  

Finds any other allocations of the same type

Same location,
   same callstack
   different callstack
  all callstacks

Finds other allocations made at the source code location:
  via the same callstack

  different callstacks

  or any callstack  

Same function

Same source file

Same DLL

All allocations from the same function...

  or the same file  

  or the same DLL  

Class allocations

All allocations, reallocations or deallocations from the same C++ class  

Relations to 'this'

Finds various other events relating to the selected object:

 

Allocator of this - only for reallocated objects

Reallocation of this

Reallocation of this address at same address

Reallocation of this address at different address

Deallocation of this

Allocations, reallocations, deallocations

Referenced by this - these two need the target application to still be running

Referencing this

Allocations within

For memory allocations, finds all other allocations within a range of 32 bytes up to 4Kb of this one

Allocations prior

Allocations after

For memory allocations, finds the previous 5, 10 or 20 allocation events

  or the next 5, 10 or 20 events

Errors

Shows any known damaged memory allocation information relating to this entry

 

 

right_mouse_buttonMenu option: filters

 

The filter options here are identical to that of the Memory tab menu options.

 

The three filter options on the menu let you create different types of filters at different scopes, using various attributes of the selected data item.

 

The types and scopes of filters in Memory Validator are described in detail elsewhere, but here's a quick summary:

 

Local filters instructionStep affect the current tab only and are managed locally via the filters button

Session filters instructionStep affect all tabs until the end of the session, and are saved with sessions

Global filters instructionStep affect all tabs, and are persistent between sessions until removed from the global filters
 

For each scope, you can create instant, temporary or custom filters:

 

Instant instructionStep quick and easy - this uses the selected data item and requires no further input from you

Temporary instructionStep like instant filters but not saved with any session data

Custom instructionStep allows you to define the characteristics of the filter
 

Finally - for each scope and type of filter, you can use any of the following elements of the selected data item as the filtering characteristic:

 

analysis-filters-menu

 

A fourth option allows you to filter the next run by DLL, either excluding that DLL, or including that DLL, in the list of DLLs that will be monitored.

 

The Hooked DLLs settings dialog is displayed.

 

 hookedDLLsSettingsDialog

 

 

right_mouse_buttonMenu option: editing source code

 

Edit Source Code... instructionStep opens the default or preferred editor to edit the source code

 

 

right_mouse_buttonMenu option: copy special

 

The copy special sub-menu lets you copy to the clipboard any of the following attributes, (or all the information):

 

copy-special-menu

 

See the same option on the Memory view menu for more information.

 

 

 

right_mouse_buttonMenu option: bookmarks and watermarks

 

Bookmarks allow you to find a data item easily at a later date, while watermarks are used above to show only those items between two points in time

 

Add Bookmark... instructionStep adds a bookmark for the selected item

 

Add Watermark... instructionStep adds a watermark for the selected item

 

 

right_mouse_buttonMenu options: collapse / expand trace

 

Collapse or Expand Trace instructionStep simply shows and hides data item information, the same as using the expand-symbol or collapse-symbolbuttons

 

Collapse All instructionStep completely collapses all data items in the upper window, including any source code views that were open

 

Expand All instructionStep expands all data items down to but not including the source code snapshots