| 11 | 11 | * Converts the flat representation to a control-flow graph, with Cmm statements representing instructions in the basic blocks. |
| 12 | 12 | * Implements calling conventions for call, jump, and return instructions: all parameter passing is turned into data-movement instructions (register-to-register move, load, or store), and stack-pointer adjustments are inserted. After this point, calls, returns, and jumps are just control-transfer instructions -- the parameter passing has been compiled away. |
| 13 | 13 | * How do we refer to locations on the stack when we haven't laid it out yet? The compiler names a stack slot using the idea of a "late compile-time constant," which is just a symbolic constant that will be replaced with an actual stack offset when the stack layout is chosen. |
| | 14 | 0. Code expansion (instruction selection): ZGraph Cmm<stack slots, compile-time constants> -> ZGraph Instrs<stack slots, compile-time constants> |
| | 15 | * Expands each Cmm instruction into a series of instructions. The representation of an instruction can be chosen by the back end. In some compilers (vpo, gcc, QC--), machine instructions are represented using RTLs. But Machine SUIF uses a target-specific, abstract representation that must satisfy a well-defined interface (i.e. by using a typeclass). It would be nice to support both. |
| | 16 | 0. Optimizer: ZGraph Instrs<stack slots, compile-time constants> -> ZGraph Instrs<stack slots, compile-time constants> |
| | 17 | |
| | 18 | Implicit in this pipeline: |
| | 19 | * Besides the expander, (parts of) the optimizer, and the code emitter, the rest of the passes should work on any chosen representation of instructions. Typeclasses are our friends. |
