Constant folding

[Adriano dos Santos Fernandes]

Hi!

For `constant c1 integer = 1 + 2;`

Why is this BLR used, instead of optimize and compute the final value?

blr_version5,
blr_cast, blr_long, 0,
blr_add,
blr_literal, blr_long, 0, 1,0,0,0,
blr_literal, blr_long, 0, 2,0,0,0,
blr_eoc


Adriano

[Artyom Abakumov]

Initially, I was generating the final value. But then I discovered that without the original blr, it was impossible to track dependencies.

среда, 27 мая 2026 г. в 03:06:45 UTC+3, Adriano dos Santos Fernandes:

[Dimitry Sibiryakov]

Artyom Abakumov wrote 27.05.2026 10:14:
> But then I discovered that without the original blr, it was impossible to track
> dependencies.

Aren't they tracked by table RDB$DEPENDENCIES?

--
WBR, SD.

[Artyom Abakumov]

I am not sure it is enouth since the csb_get_dependencies flag is present duing the BLR Parsing stage

[Dimitry Sibiryakov]

Artyom Abakumov wrote 27.05.2026 10:24:
> I am not sure it is enouth since the csb_get_dependencies flag is present duing
> the BLR Parsing stage

IMHO it is an artifact from the times when BLR could be updated directly.

--
WBR, SD.

[Alex Peshkoff]

No, it's set when parser should collect dependencies during parse. See collectingDependencies() function.

[Dimitry Sibiryakov]

'Alex Peshkoff' via firebird-devel wrote 27.05.2026 12:41:
>>   IMHO it is an artifact from the times when BLR could be updated directly.
>
> No, it's set when parser should collect dependencies during parse. See
> collectingDependencies() function.

Do you mean BLR parser or SQL parser?

AFAIU, first one is redundant for SQL and is kept to support
IRequest::compile() only, so the flag csb_get_dependencies should be reset
during BLR parse if the dependencies are already collected by SQL parser or
received from RDB$DEPENDENCIES table (for stored objects).

--
WBR, SD.

[Alex Peshkoff]

Not sure redundant or not - but it controls collecting information into RDB$DEPENDENCIES table.