scalus.sir.lowering

ComplexLoweredValue is a base trait for lowered values that consist of multiple subvalues. ownVars - var that used in subvalues but defined in this value. (i.e. not propagated up in dominatedUplevelVars)

Represent a variable which is dependent on another variable. i.e. var x1 = (toOtherReperesentation(y))

Values with id which can be represented by variables (if needed).

Identificatin is id.

Representation for lambda function. By default, lanbda-s accept default reperesentation for input and output types. But when we pass functions to type-parametrized functions, then calling party does not know about real parameter types and can't use default representation, so pass parameters as packed data.

So, we translate higher-order functions to packed data representation when pass as arguments to type-parametrized functions.

SEA of nodes - like representation. E.e. each value is node, which manage dependencies. LoweredValue:

• represents a value in lowered SIR, which is
• a generator of a block of code with generate specific SIRType in specific representation. -- (representation is LoweredValueRepresentation, which can be term or data in specoific encoding)
• some lowered values can be named (see IdentifiableLoweredValue and maintain a set of dependencies) The idea of SEA of nodes -- than we can generate code 'by need' based on dependencies. I.e. if value not used at all - code will not be generated, if value used once -- no intermediate construction will be created and code will be generated directly in place of usage. If value used multiple times -- it will be generated near the usage (i.e. in the nearest block, which contains all depended).

The idea of SEA of nodes described in the paper: Cliff Click. 1995. Global code motion/global value numbering. SIGPLAN Not. 30, 6 (June 1995), 246–257. "https://doi.org/10.1145/223428.207154"

We have a quite different code (non-SSA form, only dominators), but the main idea of relaxing order is the same,

representation, depends on the type of the value.

Change in supplied SIR

A proxy which change only the representation of the input value (without changing the underlying generated code)

A proxy which changes the input value to be specific type and representation.

TypeVarRepresentation is used for type variables. Usually this is a synonym for some other specific-type representation. When this is builtin type variable, it can be freely used in any type representation, but when it is not builtin (scala type-var) it can be used only with packed data representation.