[xlscc] Use empty LeafTypeTree for type indexing instead of GetLeafTypes

This change updates the continuation analysis to use xls::LeafTypeTree for representing and checking the types of source nodes, replacing the previous method of using flat vectors of leaf types via an internal function not intended for public use.

PiperOrigin-RevId: 846881182

Implement state to register I/O lowering pass in codegen v1.5.

PiperOrigin-RevId: 846495277

Add support for non-synthesizable functions in XLS IR.

Introduces a `#[non_synth]` attribute for functions, which marks them as not being synthesized. Adds decorator estimators (`FilterNonSynth`) for area and delay models to ignore nodes within non-synth functions during optimization. Updates the IR parser, verifier, and non-synth separation pass to handle this new attribute.

This is needed to ensure that all passes are able to cope with the existence of non-synth function invokes during the optimization process.

PiperOrigin-RevId: 845962215

Automated Code Change

PiperOrigin-RevId: 845568724

Automated rollback of commit 5adf39a906a191135154f7ad17c60252fc556f43.

PiperOrigin-RevId: 845028977

Automated Code Change

PiperOrigin-RevId: 844582048

Rollback of BitProvenance lazy compute + SignExtend improvement CL, w…

Automated rollback of commit f313d8761df09a3c58a8d153ebd5cac0995c15f0.

PiperOrigin-RevId: 843448532

[codegen 1.5] Implement FunctionIOLoweringPass.

This pass converts function parameters into InputPorts and the function's return value into an OutputPort within a ScheduledBlock; it also handles adding I/O flopping and valid signals as requested.

PiperOrigin-RevId: 842895058

Add clock and reset ports in ScheduledBlockConversionPass.

This required re-factoring the scheduled block parsing logic in IrParser to treat blocks in a more uniform way (as previously done with scheduled functions and procs), because we were missing the logic to properly deal with the ports.

PiperOrigin-RevId: 842453627