Re: Use Bohem's GC for compiler proper in 4.1?

["Sam Lauber" <sam124 at operamail dot com>]

Perhaps then a scheme in which the compiler 

 1) compresses all tree structures (this would be a good project)
 2) after each pass, all internal structures are freed unless doing so would 
create a dead pointer (maybe an -Om option like -Os but saves compilation 
memory?)
 3) dosen't use memory in general, i.e do things like 
int i;
for (i = 0; i != n_something; i++)
  putc(getc(fp), ofp);

instead of things like 

pointer_to_something = malloc(n_something * sizeof(int));
fgets(n_something, pointer_to_something, fp);
fputs(pointer_to_something, ofp);

 4) use less memory-intensive alogrithms and investigate using more 
memory-efficent repersentations

Samuel Lauber

>   > >  > I know that Bohem's GC is used in the Java runtime for GCC.
>   > >  > However, the compiler proper itself can _really_ cramp people's
>   > >  > avalible RAM (for those who don't belive me and have Windows w/
>   > >  > DJGPP, change all the memory controls from `auto' to the highest
>   > >  > value and just try to compile libiberty/regex.c), so my suggestion
>   > >  > is usage of Bohem's GC in the compiler proper itself.
>   > >
>   > > Do you have any reason to believe that such a change would reduce
>   > > memory consumption?
>   >
>   > I should note this is a loaded question, because anyone who has
>   > actually tried using boehm's gc with gcc will tell you the memory
>   > usage actually increases, not decreases.
>   >
>   > It's almost as if conservative mark and sweep is not going to work
>   > as well as accurate mark and sweep.
> 
> Astonshing, isn't it?  :-)
> 
> To be fair to the Boehm gc, though: it isn't inherently a conservative
> collector, but will also do precise gc.
> 
> Andrew.
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