[fpc-devel] Quick question on VMT / writeable or protected memory

[Jonas Maebe]

On 14/04/2021 17:49, Alfred via fpc-devel wrote:
> The mORMot[1] sources could give you some info.
> During runtime, it patches the exe-memory to redirect function calls.
> Hard part was to get around the W^X memory protection on some BSD's.
> 
> Look at:
> 
> procedure PatchCode(Old,New: pointer; Size: integer; Backup: pointer;
> inside SynCommons.pas
> 
> function TInterfaceFactory.GetMethodsVirtualTable: pointer;
> inside mORMot.pas

Please don't use that kind of hacks. It also breaks in case WPO is used
and some calls get devirtualised at compile time.


Jonas