refactor(backend-common): Avoid memory accesses on zero size reads

[DennisInSky]

Partially resolves #2095.

• do not access memory on zero size reads

It is not quite clear what needs to be changed/optimised in lazy-pages with regards to it. @grishasobol can you please clarify?

@reviewer-or-team

[shamilsan]

Great 👍

[NikVolf]

@grishasobol ?

[grishasobol]

Change this comment please

gear/lazy-pages/src/host_func.rs

Lines 112 to 114 in 11068bc

	// TODO: here we suppose zero byte access like one byte access, because
	// backend memory impl can access memory even in case access has size 0.
	// We can optimize this if will ignore zero bytes access in core-backend (issue #2095).

[DennisInSky]

Change this comment please

gear/lazy-pages/src/host_func.rs

Lines 112 to 114 in 11068bc

	// TODO: here we suppose zero byte access like one byte access, because
	// backend memory impl can access memory even in case access has size 0.
	// We can optimize this if will ignore zero bytes access in core-backend (issue #2095).

@grishasobol can you please elabortae on how it has to be changed? I asked you about it above - I do not quite understand how it can be optimised or how the comment has to be changed.

[grishasobol]

Change this comment please

gear/lazy-pages/src/host_func.rs

Lines 112 to 114 in 11068bc

	// TODO: here we suppose zero byte access like one byte access, because
	// backend memory impl can access memory even in case access has size 0.
	// We can optimize this if will ignore zero bytes access in core-backend (issue #2095).

@grishasobol can you please elabortae on how it has to be changed? I asked you about it above - I do not quite understand how it can be optimised or how the comment has to be changed.

Ok, leave only the first sentence

 // NOTE: here we suppose zero byte access like one byte access, because 
 // backend memory impl can access memory even in case access has size 0. 

We cannot make panic here because we must support old runtimes