HCoop / hcoop / debian / mlton.git / blame
| Commit | Line | Data |
|---|---|---|
| 7f918cf1 CE |
1 | RSSA |
| 2 | ==== | |
| 3 | ||
| 4 | <:RSSA:> is an <:IntermediateLanguage:>, translated from <:SSA2:> by | |
| 5 | <:ToRSSA:>, optimized by <:RSSASimplify:>, and translated by | |
| 6 | <:ToMachine:> to <:Machine:>. | |
| 7 | ||
| 8 | == Description == | |
| 9 | ||
| 10 | <:RSSA:> is a <:IntermediateLanguage:> that makes representation | |
| 11 | decisions explicit. | |
| 12 | ||
| 13 | == Implementation == | |
| 14 | ||
| 15 | * <!ViewGitFile(mlton,master,mlton/backend/rssa.sig)> | |
| 16 | * <!ViewGitFile(mlton,master,mlton/backend/rssa.fun)> | |
| 17 | ||
| 18 | == Type Checking == | |
| 19 | ||
| 20 | The new type language is aimed at expressing bit-level control over | |
| 21 | layout and associated packing of data representations. There are | |
| 22 | singleton types that denote constants, other atomic types for things | |
| 23 | like integers and reals, and arbitrary sum types and sequence (tuple) | |
| 24 | types. The big change to the type system is that type checking is now | |
| 25 | based on subtyping, not type equality. So, for example, the singleton | |
| 26 | type `0xFFFFEEBB` whose only inhabitant is the eponymous constant is a | |
| 27 | subtype of the type `Word32`. | |
| 28 | ||
| 29 | == Details and Notes == | |
| 30 | ||
| 31 | SSA is an abbreviation for Static Single Assignment. The <:RSSA:> | |
| 32 | <:IntermediateLanguage:> is a variant of SSA. |