• Benjamin Thaut (24/24) Dec 18 2017 For my dll work I need some pointers from someone who has a
• Walter Bright (7/15) Dec 26 2017 The model used internally by the compiler is "as if" it was instantiated...

Benjamin Thaut <code benjamin-thaut.de> writes:

For my dll work I need some pointers from someone who has a 
deeper understanding of how the template implementation inside 
dmd works. Here is the problem

Given a template instance I need to know which module caused this 
template to be instanciated. I don't need the module the template 
was declared in but instead the module that triggered the 
instanciation. This also has to work in cases where the compiler 
re-uses existing template instances. In a re-use case I need the 
module that caused instaciation of the re-used instance.


Example:

module a;

struct SomeTemplate(T){ ... }

module b;

SomeTemplate!int g_var;


When looking at template instace caused by the g_var declaration 
I need to know that it was instanciated because the module "b" 
requested it.

Looking at the data structures conntected to templates and the 
template instance I got the impression that this information is 
currently not stored in the compiler internal data structures. In 
case this actually is not stored yet, what would be the best 
place to add it?

Kind Regards
Benjamin Thaut

Walter Bright <newshound2 digitalmars.com> writes:

On 12/18/2017 4:33 AM, Benjamin Thaut wrote:
 For my dll work I need some pointers from someone who has a deeper
understanding 
 of how the template implementation inside dmd works. Here is the problem
 
 Given a template instance I need to know which module caused this template to
be 
 instanciated. I don't need the module the template was declared in but instead 
 the module that triggered the instanciation. This also has to work in cases 
 where the compiler re-uses existing template instances. In a re-use case I
need 
 the module that caused instaciation of the re-used instance.

The model used internally by the compiler is "as if" it was instantiated every 
time it was used, and then duplicates are discarded by the linker. The compiler 
does an optimization internally by looking to see if it was already 
instantiated, and just pointing to that instead of instantiating it again.

I suspect the problem you're having is a dependency on who instantiated it that 
shouldn't be a dependency.