How to debug inno-setup exceptions - delphi

Question

I compiled inno-setup with XE6 myself. (I know, the document suggested older delphi versions, but I only have new IDE)
I want to use pascal script to customize setup. But even I added a simplest [Code] section, the created installation crash.
[Code]
function InitializeSetup(): Boolean;
begin
end;
The created setup.exe failed while being installed:
[22:10:29.945] *** Setup started
[22:10:36.182] Setup version: Inno Setup version 5.5.4 (u)
[22:10:36.186] Original Setup EXE: D:\Classics\Save\Installer\Win_Platform\Inno Setup\test\Output\setup.exe
[22:10:36.190] Setup command line: /SL5="$911152,176640,176640,D:\Classics\Save\Installer\Win_Platform\Inno Setup\test\Output\setup.exe" /SPAWNWND=$7B05B8 /NOTIFYWND=$1150B10 /DEBUGWND=$74002E
[22:10:36.200] Windows version: 6.2.9200 (NT platform: Yes)
[22:10:36.203] 64-bit Windows: Yes
[22:10:36.209] Processor architecture: x64
[22:10:36.212] User privileges: Administrative
[22:10:37.660] 64-bit install mode: No
[22:10:37.674] Created temporary directory: C:\Users\CAOSHU~1\AppData\Local\Temp\is-5AOTJ.tmp
[22:10:37.717] InitializeSetup raised an exception (fatal).
[22:10:37.725] Exception message:
[22:10:37.734] Message box (OK):
Access violation at address 006043C0 in module 'setup.tmp'. Read of address 00000014.
[22:11:03.501] User chose OK.
[22:11:03.515] Deinitializing Setup.
[22:11:04.424] *** Setup exit code: 1
Perhaps the way I compiled inno setup has some problems. I need not use XE6? But how to debug and figure out where the problem is？
It is not some code which crashes when it runs. It is a setup.exe which created by inno setup.

Answer 1

The value returned by InitializeSetup() is undefined.
function InitializeSetup(): Boolean;
begin
result := true;
end;
You get an undefined behaviour because of this. If most of the time the result will be false (last 8 bits of RAX == 0), this is not always the case and you'll get a seriously "hard to understand" issue, particularly when, for no reason, it'll work.