Custom malloc fails after gcc-5.x due to changes in eh_alloc.cc

[Kaushik Phatak]

Hi,
One of our application uses its own custom malloc implementation.
This code worked well in gcc-4.9.1, however once we switched the gcc-5.3.0 this stopped working.

During initialization of the application (i.e. before it makes a call to malloc), it executes an
init function -> "hardware_mem_init"
This is called using a constructor with "__attribute__ ((init_priority (101)))" to ensure 
this it gets called before any other constructor call.

However, some class of libstdc++ library, is trying to allocate memory using malloc, 
and this happens well before our process gets a chance to initialize and 
setup the memory blocks properly (using hardware_mem_init).

We narrowed down the issue to be caused due to the following patch which gets introduced in gcc-5.1.0,
[PATCH] Fix PR64535 - increase emergency EH buffers via a new allocator
https://gcc.gnu.org/ml/gcc-patches/2015-01/msg00681.html

This creates an emergency pool for allocating memory to handle higher number of bad_alloc's, which is good;
however it uses malloc which ends up calling our customized routine and our application fails as it
does not get a chance to run the hardware_mem_init.

Is there any way to get this to work by setting up some init_priority? Or some other option
to allocate the emergency pool without using malloc?
Any advice/feedback would be appreciated.

I will try and share a minimal code here as well.

Best Regards,
Kaushik M. Phatak

Please excuse any disclaimers at end of this mail.
These are auto-inserted by the company e-mail client.