`is_pub` added to `Fn` would cost us an additional 8
bytes of memory per function, which is a real bummer
since it's only 1 bit of information.
If we wanted to really remove this, I suspect we could
make this a function isPub() which looks at the AST of
the corresponding Decl and finds if the FnProto AST node
has the pub token. However I saw an easier approach -
The data of whether something is pub or not is actually
a property of a Decl anyway, not a function, so we can
look at moving the field into Decl. Indeed, doing this,
we see that Decl already has deletion_flag: bool which
is hiding in the padding bytes between the enum (1 byte)
and the following u32 field (generation). So if we put
the is_pub bool there, it actually will take up no
additional space, with 1 byte of padding remaining.
This was an easy reworking of the code since any
func.is_pub could be changed simply to func.owner_decl.is_pub.
I also modified `Var` to make the init value non-optional
and moved the optional bit to a has_init: bool field. This is worse from
the perspective of control flow and safety, however it makes
`@sizeOf(Var)` go from 32 bytes to 24 bytes. The more code we can fit
into memory at once, the more justified we are in using the compiler as
a long-running process that does incremental updates.
During codegen we do not yet know the indexes that will be used for
called functions. Therefore, we store the offset into the in-memory
code where the index is needed with a pointer to the Decl and use this
data to insert the proper indexes while writing the binary in the flush
function.
We still want this compile error but I'm giving up on implementing it
correctly in stage1. It's been buggy and has false positives sometimes.
I left the test cases there, but commented out, so that when we go
through the stage1 compile error cases and get coverage for them in
stage2 we can reactivate the test cases.
closes#2154
* introduce a dump() function on Module.Fn which helpfully prints to
stderr the ZIR representation of a function (can be called before
attempting to codegen it). This is a debugging tool.
* implement x86 codegen for loops
* liveness: fix analysis of conditional branches. The logic was buggy
in a couple ways:
- it never actually saved the results into the IR instruction (fixed now)
- it incorrectly labeled operands as dying when their true death was
after the conditional branch ended (fixed now)
* zir rendering is enhanced to show liveness analysis results. this
helps when debugging liveness analysis.
* fix bug in zir rendering not numbering instructions correctly
closes#6021
Andrew Kelley