Debug Lazarus sources step by step
lazarus / 12-Debugger

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s73 · 2016-11-01 15:06

I have error with

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i var  f:
TField;  v: variant;begin...        v := f.Value; where f is TinyInt
ASE field (byte): v contains negative value ($FFFFFFVV). To trace
error I should somehow trace into GetFieldValue. I've tried rebuild
Lazarus with profile "Debug IDE" (it seems gives me only memory
usage), tried to open LCL, LCLBase and FCL (Open Loaded Package, Open,
there already "Generate debugging" checked, tried both "automatic" or
"Dwarf with sets"), compiled, rebuilded Lazarus - but still can't
trace into Lazarus DB code.
Can someone provide step by step "How to" to do that? Lazarus 1.6 for
Win64. Thanks.

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JuhaManninen · 2016-11-01 16:50

How did you try to trace Lazarus DB code? Debugging should work when
you have built Lazarus with profile "Debug IDE".
Just open the ide\lazarus.lpi project and debug it as any project. It
is briefly explained here:
 http://wiki.freepascal.org/Extending_the_IDE#Debugging_the_IDE

You can also use GDB directly. When debugging a Lazarus instance using
another Lazarus instance, you must pay attention to which window
belongs to which instance.
Anyway, that is how I often debug the IDE.
An alternative way is to add DebugLn() calls to the source and look at
their output. It is the best way for debugging mouse event handlers
because mouse may stop working in the IDE after a breakpoint.

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howardpc · 2016-11-01 17:58

Quote from: s73 on November 01, 2016, 04:06:00 pmstill can't trace
into Lazarus DB code.

It may be that your fpc is not built with debug info.
To do that see, for example, this thread
http://forum.lazarus.freepascal.org/index.php/topic,20335.msg117259.ht
ml#msg117259

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s73 · 2016-11-02 11:56

Quote from: JuhaManninen on November 01, 2016, 05:50:13 pmHow did you
try to trace Lazarus DB code? Debugging should work when you have
built Lazarus with profile "Debug IDE".
Just open the ide\lazarus.lpi project and debug it as any project. It
is briefly explained here:
 http://wiki.freepascal.org/Extending_the_IDE#Debugging_the_IDE
It is not clear for me is this profile "Debug IDE" to exactly debug
IDE (environment) or is it as Delphi's compiler option "Use debug
.dcus" that allows to step into Delphi sources. I guess this option to
exactly debug IDE, not IDE environment that allows to debug
Lazarus/FPC sources. What I want is to trace errors I have with some
types of fields under FPC (Byte fields, BCD etc that works under
Delphi but fails with errors under FPC).

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s73 · 2016-11-02 12:36

Quote from: howardpc on November 01, 2016, 06:58:09 pmIt may be that
your fpc is not built with debug info.
To do that see, for example, this thread
http://forum.lazarus.freepascal.org/index.php/topic,20335.msg117259.ht
ml#msg117259
So I have in fpc\3.0.0\source\packages\fcl-db\ several makefiles. To
rebuild with debug information I should do exactly what?

When I trying to build as suggested I have
QuoteD:\lazarus\fpc\3.0.0\source\packages>make OPT=-g
MAKE Version 5.41  Copyright (c) 1987, 2014 Embarcadero Technologies,
Inc.
Error makefile 14: Command syntax error
...
or
QuoteD:\lazarus\fpc\3.0.0\source\packages>d:\lazarus\fpc\3.0.0\bin\x86
_64-win64\make OPT=-g
d:/lazarus/fpc/3.0.0/bin/x86_64-win64/make -C fpmkunit bootstrap
make[1]: Entering directory
`D:/lazarus/fpc/3.0.0/source/packages/fpmkunit'
d:/lazarus/fpc/3.0.0/bin/x86_64-win64/gmkdir.exe -p
units_bs/x86_64-win64
d:/lazarus/fpc/3.0.0/bin/x86_64-win64/ppcx64.exe src/fpmkunit.pp -n
-Fu../../rtl -FUunits_bs/x86_64-win64 -Fu../paszlib/src -Fu../hash/src
-Fi../paszlib/src   -Fi../fcl-process/src/win -Fu../fcl-process/src
-Fi../fcl-process/src/win64 -Fi../fcl-process/src/dummy
-Fu../libtar/src -g
Fatal: Can't find unit system used by fpmkunit
Fatal: Compilation aborted
make[1]: *** [bootstrap] Error 1
make[1]: Leaving directory
`D:/lazarus/fpc/3.0.0/source/packages/fpmkunit'
make: *** [fpmake.exe] Error 2

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howardpc · 2016-11-02 16:17

I don't have a current working Windows setup to test on, and give you
a step-by-step.
However I can point out one obvious problem, and warn about another.
You have Delphi installed, and Embarcadero's make.exe is in your
system path.
You'll have to reset the system path with a command line instruction
like
  path=path-to-fpc-binutils
(or however it should be written on Windows).

Also, I seem to remember that running the make.exe that is provided
with a Windows fpc installation can fail if you work with makefiles on
a drive other than c: (You're using d:, for instance). I don't know if
that is still an issue or not, but it certainly was in the past
because some of the required binutils choked if you presented them
with files not on the c: drive.

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JuhaManninen · 2016-11-02 16:54

Quote from: s73 on November 02, 2016, 12:56:24 pmIt is not clear for
me is this profile "Debug IDE" to exactly debug IDE (environment) or
is it as Delphi's compiler option "Use debug .dcus" that allows to
step into Delphi sources. I guess this option to exactly debug IDE,
not IDE environment that allows to debug Lazarus/FPC sources.
It allows you to debug all Lazarus sources, including LCL and other
packages.
For debugging FPC's source you must compile it with debug info, too.
Sometimes it is easy to copy some FPC library code and debug it as
part of your project, but it may not work in this case.

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s73 · 2016-11-10 12:16

So I made as described in http://wiki.freepascal.org/Installing_Lazaru
s#Installing_Free_Pascal_under_Windows from sources with some fixes:
makefpc.bat
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i @echo onset
myroot=c:\freepascalset myFPC=%myroot%\fpc\3.0.1set
mybinutils=%myroot%\binutilsset
PATH=%mybinutils%\i386-win32;%mybinutils%\i386-win32\binw32;cd
%myFPC%rd /s /q  %myfpc%\examplesmake clean all OPT="-glw2" install
INSTALL_PREFIX=%myFPC% PP=%mybinutils%\ppc386.exe
DATA2INC=%myFPC%\utils\data2inc.exemakelaz.bat
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i set
myroot=c:\freepascalset myFPC=%myroot%\fpc\3.0.1set
mybinutils=%myroot%\binutilsset PATH=%mybinutils%;%mybinutils%\i386-
win32\binw32;%myFPC%\bin\i386-win32;cd %myroot%\lazmake clean all
OPT="-glw2"Everything built with debug enabled OPT="-glw2" but I still
can't trace into for example "Field.AsBytes := value". When I open
fields.inc in code editor I can see there blue circles to set
breakpoints, but they do not works there.
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TBlobField.SetAsBytes(const AValue: TBytes);var  Len : Integer;begin
<- breakpoint  with GetBlobStream(bmWrite) do <- breakpoint    try   
 Len := Length(AValue);      if Len > 0 then       
WriteBuffer(AValue[0], Len);    finally      Free;    end;end; from
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i           
if FieldObj is TBlobField then              FieldObj.AsBytes := Value