Scaling rdmd up: build package at a time

[anonymous via Digitalmars-d]

On Saturday, 6 June 2015 at 19:44:15 UTC, Andrei Alexandrescu 
wrote:
> On 6/6/15 11:47 AM, Jacob Carlborg wrote:
[...]
>> I mean that rdmd should compile all files that has changed
>> including its dependencies, no more, no less. It should 
>> compile all
>> these files in one go.
>
> Yah, that's the traditional C-style module-at-a-time approach.

I think the traditional approach would be to compile modules 
separately, not "all [...] in one go".

> Somewhat paradoxically, for D it's faster to compile several 
> files at once, even though not all were affected by the change.
>
> So in the package-at-a-time approach if at least one module in 
> a package is affected by a change, the entire package gets 
> rebuilt.

This may beat separately compiling modules that needs rebuilding. 
But it doesn't beat compiling all of them at once, does it?

My understanding of things:

Current behaviour: When any module changed, pass all source files 
to one dmd invocation.

The makefile approach: Separately recompile every module that 
needs rebuilding; then link the new object files with the cached 
ones.

Your proposal, variant 1: For every module that needs rebuilding, 
separately recompile its whole package; then link the new object 
files with the cached ones of other packages.

Variant 2: For every module that needs rebuilding, determine what 
package it belongs to; then pass the source files of those 
packages and the cached object files of other packages to one dmd 
invocation.

The seemingly obvious thing to do: Pass the source files that 
need rebuilding and the object files of other modules to one dmd 
invocation.