stephen <chency666@xxxxxxxxx> writes:
> we want to set a scope id for each statement, for example,
>
> void main()
> {
> int i=1; Â Â Â Â -------------------> Âscope = 1;
> if (i>1)
> {
> Âi=2; Â Â Â Â Â Â--------------------> scope =2; because it is inside a brace;
> Âif(i == 2)
> Â{
> Â i=i+1; Â Â Â Â --------------------> scope =3; because it is inside two brace;
> Â i=3; Â Â Â Â Â --------------------> scope =3; because it is inside two brace;
> Â}
> Âi=i-1; Â Â Â Â Â--------------------> scope =2; because it is inside a brace;
> }
> i=i+1; Â Â Â Â Â --------------------> scope =1;
> }
>
> And we want to add this scope information in the assembler code, like
> this. (As soon as it reaches a "{", the scope will add "1" and the
> scope will remove "1" when it reaches a "}" )
gcc doesn't work that way. It renames the local variables, throws away
the scopes, and rearranges statements across scopes.
> But I also found basic block struct has a variable "loop_depth", can I use it?
loop_depth refers to the number of nested loops, not nested scopes.
There can be loops without scopes (e.g., using goto statements) and
scopes without loops (e.g., the above code).
Ian
