Determination of argument passed to operator new

[Nikolaus Dunn]

Thanks!

On 10/14/2016 01:29 PM, Jonathan Wakely wrote:
> On 14 October 2016 at 18:26, Nikolaus Dunn wrote:
>> Hi all,
>>
>> According to what I've read, the "new" and "new []" expressions are
>> implemented by the compiler to compute the size of the storage required by
>> the type and then make a call to one of the "new" operators to allocate
>> memory and handle construction. I've found the code for the "new" operators
>> in gcc, but I can't find where in the gcc code the compiler determines the
>> value to be passed to the new operator and then sets up the actual call.
> Look for build_new() in gcc/cp/init.c
>
>> The reason I'm asking is I am interested in how the compiler implements the
>> "new []" expression. In particular, how it is storing the array size and is
>> there any extra overhead being stored and what it is, if any.
> That is specified by the ABI, see
> https://mentorembedded.github.io/cxx-abi/abi.html#array-cookies
>
>> I'm assuming it is the actual parser/code generator that is doing this since
>> they are unique expressions and not simply function calls. Can someone point
>> me to where this code is being generated or correct my ignorance if I am way
>> off base?