Show SSA deletes the databus

[sirasistant]

Aim

Compiling functions that use the databus with --show-ssa

Expected Behavior

Function should not be modified

Bug

Databus is removed

Compiled ACIR for main (unoptimized):
func 0
current witness index : 2
private parameters indices : [0, 1]
public parameters indices : []
return value indices : []
BLACKBOX::RANGE [(0)] [ ]
BLACKBOX::RANGE [(1)] [ ]
EXPR [ (1, _0) (-1, _2) 1 ]
BLACKBOX::RANGE [(2)] [ ]
EXPR [ (-1, _1) (1, _2) 0 ]

(no init calldata or returndata shown anymore)

To Reproduce

Workaround

None

Workaround Description

No response

Additional Context

No response

Project Impact

None

Blocker Context

No response

Nargo Version

No response

NoirJS Version

No response

Proving Backend Tooling & Version

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Would you like to submit a PR for this Issue?

None

Support Needs

No response

[asterite]

I found that the "normalize IDs" SSA pass doesn't populate the DataBus structure of a function dfg:

noir/compiler/noirc_evaluator/src/ssa/opt/normalize_value_ids.rs

Line 63 in f6dfbcf

Function::clone_signature(new_id, function)

noir/compiler/noirc_evaluator/src/ssa/ir/function.rs

Lines 76 to 80 in f6dfbcf

	pub(crate) fn clone_signature(id: FunctionId, another: &Function) -> Self {
	let mut new_function = Function::new(another.name.clone(), id);
	new_function.runtime = another.runtime;
	new_function
	}

Doing a simple clone() doesn't work because the IDs change, so we have to replace the IDs in that data structure too.

@jfecher I'll try, but someone with more knowledge about this DataBus type might be able to do it faster.

[asterite]

Actually, maybe it's not that hard, there's IdMaps which maps the IDs... I'll try :-)