diff options
Diffstat (limited to 'src/cmd/8g/opt.h')
| -rw-r--r-- | src/cmd/8g/opt.h | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/src/cmd/8g/opt.h b/src/cmd/8g/opt.h index ed6eb15ab..b80043e0f 100644 --- a/src/cmd/8g/opt.h +++ b/src/cmd/8g/opt.h @@ -47,12 +47,16 @@ typedef struct Reg Reg; typedef struct Rgn Rgn; +// A Reg is a wrapper around a single Prog (one instruction) that holds +// register optimization information while the optimizer runs. +// r->prog is the instruction. +// r->prog->regp points back to r. struct Reg { - Bits set; - Bits use1; - Bits use2; + Bits set; // variables written by this instruction. + Bits use1; // variables read by prog->from. + Bits use2; // variables read by prog->to. Bits refbehind; Bits refahead; @@ -68,13 +72,13 @@ struct Reg uint16 loop; // x5 for every loop uchar refset; // diagnostic generated - Reg* p1; - Reg* p2; + Reg* p1; // predecessors of this instruction: p1, + Reg* p2; // and then p2 linked though p2link. Reg* p2link; - Reg* s1; + Reg* s1; // successors of this instruction (at most two: s1 and s2). Reg* s2; - Reg* link; - Prog* prog; + Reg* link; // next instruction in function code + Prog* prog; // actual instruction }; #define R ((Reg*)0) |