• Alfred Pincher (11/11) Aug 06 2016 Hi, I have written some code that tracks all memory allocations
• Basile B. (2/14) Aug 06 2016 http://www.cprogramming.com/debugging/valgrind.html
• Cauterite (30/31) Aug 08 2016 If you want to implement that kind of allocation tracking you'll

Alfred Pincher <imboile turst.com> writes:

Hi, I have written some code that tracks all memory allocations 
and deallocations when using my own memory interface. It is non 
gc based.

It reports the results of each allocation when the memory balance 
for the pointer allocated is non-zero. It gives the stack trace 
of the allocations and deallocations if they exist long with 
statistics collected from the allocators and deallocators.

It is very handy but I rely on hacks to accomplish the task. Does 
D have any solution for handling non-gc and/or gc memory 
inspection? With my code, if I miss a free, it is reported, this 
is a very nice feature. I hope D has something similar?

Basile B. <b2.temp gmx.com> writes:

On Sunday, 7 August 2016 at 00:28:40 UTC, Alfred Pincher wrote:
 Hi, I have written some code that tracks all memory allocations 
 and deallocations when using my own memory interface. It is non 
 gc based.

 It reports the results of each allocation when the memory 
 balance for the pointer allocated is non-zero. It gives the 
 stack trace of the allocations and deallocations if they exist 
 long with statistics collected from the allocators and 
 deallocators.

 It is very handy but I rely on hacks to accomplish the task. 
 Does D have any solution for handling non-gc and/or gc memory 
 inspection? With my code, if I miss a free, it is reported, 
 this is a very nice feature. I hope D has something similar?

http://www.cprogramming.com/debugging/valgrind.html

Cauterite <cauterite gmail.com> writes:

On Sunday, 7 August 2016 at 00:28:40 UTC, Alfred Pincher wrote:
 this is a very nice feature. I hope D has something similar?

If you want to implement that kind of allocation tracking you'll 
probably want to use gc_getProxy()+gc_setProxy(). They're global 
C functions you can access by declaring:
extern(C) gc.gcinterface.GC gc_getProxy() nothrow;
extern(C) void gc_setProxy(gc.gcinterface.GC);

First call gc_getProxy() to get the real GC instance and save it 
somewhere.
Then call gc_setProxy() with your object implementing the GC 
interface functions, and in each function forward to the 
corresponding function of the real GC instance, after any 
statistic-gathering code you want run.

Something like this:

__gshared GC RealGcInstance = gc_getProxy();
__gshared GC MyProxy = new class GC {
	// ...
	extern(C) void gc_free(void* Ptr) nothrow {
		printf("freeing pointer %x\n", Ptr); // or whatever
		return RealGcInstance.free(Ptr);
	};
	// ... etc.
};
gc_setProxy(MyProxy);

I haven't tested this method myself, but it will probably work. 
Refer to 
https://github.com/dlang/druntime/blob/master/src/gc/proxy.d and 
https://github.com/dlang/druntime/blob/master/src/gc/gcinterface.d

Also remember that you can't invoke the GC from inside the proxy 
functions. Using helper functions marked  nogc might make it 
easier to avoid.