[cfe-dev] Proposal: Type-Aware Memory Profiling

[Onewastedlife]

Interesting.. Why would you not preserve the context information as well? 

Regard,
Ramneek

On Dec 6, 2012, at 11:28 PM, Dai Mikurube <dmikurube at chromium.org> wrote:

> Hi cfe-dev,
> 
> I'd like to propose a way of Type-Aware Memory Profiling in Clang.  It was one of the lightning talks at the DevMtg by Nico Weber on behalf of me.  Slides and Video were recently published.
> * http://llvm.org/devmtg/2012-11/Weber_TypeAwareMemoryProfiling.pdf
> * http://llvm.org/devmtg/2012-11/videos/Weber_TypeAwareMemoryProfiling.mp4
> 
> Object's type information is useful to profile memory usage in a process.  Type info is, however, hard to use in C++ programs.  Our proposal is to make it easy by compiler's help.  We implemented an early prototype, and the prototype has been working in Chromium project for a couple of months.
> 
> 
> What do you think?  I wonder if I could have your opinions about it.  The details are discussed in this document.  https://docs.google.com/document/d/1zyJ3FJhheJ5iSxYaMXARkZcR61tx6r44euMJbWw8jFY/edit
> 
> tl;dr, we did it by user-defined intercepting functions for operator new and delete.  If a developer defines a function __op_new_intercept__ (and if a compiler option is given!), the function intercepts operator new calls.
> 
> 
> An example follows :
> 
> $ cat typeaware.cc
> #include <stdio.h>
> #include <typeinfo>
> 
> struct Klass {
>   int x, y, z;
> };
> 
> void* __op_new_intercept__(
>     void* address, std::size_t size, const std::type_info& type) {
>   printf("Allocated %lu bytes for %s at %016p.\n",
>          size, type.name(), address);
>   return address;
> }
> 
> void* __op_delete_intercept__(
>     void* address, std::size_t size, const std::type_info& type) {
>   printf("Deallocated %lu bytes for %s at %016p.\n",
>          size, type.name(), address);
>   return address;
> }
> 
> int main() {
>   int *i;
>   Klass *k;
>   i = new int(3);
>   k = new Klass();
>   delete k;
>   delete i;
>   return 0;
> }
> 
> $ clang++ -fintercept-allocation-functions typeaware.cc
> 
> $ ./a.out
> Allocated 4 bytes for i at 0x000000022df010.
> Allocated 12 bytes for 5Klass at 0x000000022df030.
> Deallocated 12 bytes for 5Klass at 0x000000022df030.
> Deallocated 4 bytes for i at 0x000000022df010.
> 
> -- 
> Dai MIKURUBE
>    dmikurube at chromium.org
> 
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
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