opt.md

Compiler optimizations

The NewASM compiler does several different optimizations by default before packing your app into a binary file. Below is a list of optimizations compiler will do.

Simple optimizations

The compiler will of course perform minor peephole optimizations such as:

1. peephole optimization, removed redundant double code

Code such as double jumps, double returns, or double reassignments, for example:

mov tlr, 3
mov tlr, 3 ; removed, it is already 3

jmp lmao
jmp smth ; removed, this line will never be reached

2. removed redundant try-catch block

Empty try-catch blocks will be ultimatively removed from the binary as they're relatively expensive.

try
; no code
catch xd

3. peephole optimization, removed redundant refetch

Double fetch instructions are removed.

4. peephole optimization, removed redundant stack memory dedication

Double resb instructions are removed.

5. peephole optimization, removed redundant kernel module entrance

Double sysenter instructions are removed.

6. peephole optimization, removed redundant memory alignment

Double align instructions are removed.

7. peephole optimization, value of a register changed to itself

Code such as:

mov tlr, *tlr

will also get removed by the compiler.

8. peephole optimization, removed dead code

Dead instructions like rem will get removed.

9. peephole optimization, removed redundant assignment before reassignment

Code like this will also be modified:

mov tlr, 6 ; removed cuz the next instruction's modifying tlr again
mov tlr, *tlr 

More complex optimizations

1. removed redundant code section reset

Redundant code section modifiers are also removed.

.start
    ; code
.start ; removed
    ; more code

Although this looks like a very simple optimization, it requires some deeper code analysis by the compiler in order to determine if the removal is 100% safe.

2. removed unreachable code block

The compiler also does deeper code analysis in order to remove unreachable code blocks such as:

jmp lmao
    ; all of this code between there 2 lines will get removed, including the jmp ins above
    ; :lmao remains because the rest of the code may use it
:lmao

3. removed useless namespace labels

The compiler also removes empty namespaces. By empty, it means no procedure, thread, data container or a variable is declared within it.

.start
    ; empty namespace
    ./lmao
        nop
        mov rax, 0
        lea tuple, 3
        ; ... etc
    ./!lmao

    ; namespace with elements
    ./lmao
        proc func
            halt 0
        end

        ; it is gonna detect empty nested namespaces
        ; the compiler creates a complex tree of namespaces
        ; analyses it from top to bottom
        ./lmao2
        ./!lmao3
    ./!lmao