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;
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)
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;
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)
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;
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)