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Commit 2d259c81 authored by Russ Cox's avatar Russ Cox
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add comments and delete dead code 

R=ken
OCL=22078
CL=22080
parent 25444d07
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Showing with 185 additions and 64 deletions
src/cmd/6g/cgen.c
View file @ 2d259c81
......@@ -4,6 +4,10 @@
#include "gg.h"
/*
* generate:
* res = n;
*/
void
cgen(Node *n, Node *res)
{
......@@ -371,6 +375,10 @@ ret:
;
}
/*
* generate:
* res = &n;
*/
void
agen(Node *n, Node *res)
{
......@@ -616,6 +624,14 @@ fieldoffset(Type *t, Node *n)
return 0;
}
/*
* generate:
* newreg = &n;
* res = newreg
*
* on exit, a has been changed to be *newreg.
* caller must regfree(a).
*/
void
igen(Node *n, Node *a, Node *res)
{
......@@ -625,6 +641,10 @@ igen(Node *n, Node *a, Node *res)
a->type = n->type;
}
/*
* generate:
* if(n == true) goto to;
*/
void
bgen(Node *n, int true, Prog *to)
{
......@@ -819,6 +839,11 @@ ret:
;
}
/*
* n is on stack, either local variable
* or return value from function call.
* return n's offset from SP.
*/
int32
stkof(Node *n)
{
......@@ -847,6 +872,10 @@ stkof(Node *n)
return -1000;
}
/*
* block copy:
* memmove(&n, &ns, w);
*/
void
sgen(Node *n, Node *ns, int32 w)
{
......
src/cmd/6g/gen.c
View file @ 2d259c81
......@@ -8,12 +8,6 @@
#include "gg.h"
#include "opt.h"
enum
{
// random unused opcode
AJMPX = AADDPD,
};
void
compile(Node *fn)
{
......@@ -334,7 +328,7 @@ loop:
break;
case OAS:
cgen_as(n->left, n->right, n->op);
cgen_as(n->left, n->right);
break;
case OCALLMETH:
......@@ -655,6 +649,9 @@ genpanic(void)
p->to.type = D_INDIR+D_AX;
}
/*
* compute total size of f's in/out arguments.
*/
int
argsize(Type *t)
{
......@@ -684,6 +681,16 @@ argsize(Type *t)
return w;
}
/*
* generate:
* call f
* if proc, generate:
* push f
* push argsize
* call newproc
* pop
* pop
*/
void
ginscall(Node *f, int proc)
{
......@@ -706,6 +713,10 @@ ginscall(Node *f, int proc)
gins(ACALL, N, f);
}
/*
* n is call to interface method.
* generate res = n.
*/
void
cgen_callinter(Node *n, Node *res, int proc)
{
......@@ -755,6 +766,9 @@ cgen_callinter(Node *n, Node *res, int proc)
setmaxarg(n->left->type);
}
/*
* generate call to non-interface method
*/
void
cgen_callmeth(Node *n, int proc)
{
......@@ -776,6 +790,10 @@ cgen_callmeth(Node *n, int proc)
cgen_call(n, proc);
}
/*
* generate function call;
* if proc, run call in new proc.
*/
void
cgen_call(Node *n, int proc)
{
......@@ -805,7 +823,7 @@ cgen_call(Node *n, int proc)
// call tempname pointer
if(n->left->ullman >= UINF) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, &afun, 0);
cgen_as(&nod, &afun);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
......@@ -815,7 +833,7 @@ cgen_call(Node *n, int proc)
// call pointer
if(isptr[n->left->type->etype]) {
regalloc(&nod, types[tptr], N);
cgen_as(&nod, n->left, 0);
cgen_as(&nod, n->left);
nod.type = t;
ginscall(&nod, proc);
regfree(&nod);
......@@ -830,6 +848,9 @@ ret:
;
}
/*
* generate code to start new proc running call n.
*/
void
cgen_proc(Node *n)
{
......@@ -852,6 +873,11 @@ cgen_proc(Node *n)
}
/*
* call to n has already been generated.
* generate:
* res = return value from call.
*/
void
cgen_callret(Node *n, Node *res)
{
......@@ -874,9 +900,14 @@ cgen_callret(Node *n, Node *res)
nod.xoffset = fp->width;
nod.type = fp->type;
cgen_as(res, &nod, 0);
cgen_as(res, &nod);
}
/*
* call to n has already been generated.
* generate:
* res = &return value from call.
*/
void
cgen_aret(Node *n, Node *res)
{
......@@ -909,6 +940,10 @@ cgen_aret(Node *n, Node *res)
gins(ALEAQ, &nod1, res);
}
/*
* generate return.
* n->left is assignments to return values.
*/
void
cgen_ret(Node *n)
{
......@@ -916,6 +951,9 @@ cgen_ret(Node *n)
gins(ARET, N, N);
}
/*
* generate += *= etc.
*/
void
cgen_asop(Node *n)
{
......@@ -1038,8 +1076,13 @@ ret:
;
}
/*
* generate assignment:
* nl = nr
* nr == N means zero nl.
*/
void
cgen_as(Node *nl, Node *nr, int op)
cgen_as(Node *nl, Node *nr)
{
Node nc, n1;
Type *tl;
......@@ -1052,8 +1095,8 @@ cgen_as(Node *nl, Node *nr, int op)
iszer = 0;
if(nr == N || isnil(nr)) {
if(nl->op == OLIST) {
cgen_as(nl->left, nr, op);
cgen_as(nl->right, nr, op);
cgen_as(nl->left, nr);
cgen_as(nl->right, nr);
return;
}
tl = nl->type;
......@@ -1170,6 +1213,16 @@ samereg(Node *a, Node *b)
return 1;
}
/*
* generate division.
* caller must set:
* ax = allocated AX register
* dx = allocated DX register
* generates one of:
* res = nl / nr
* res = nl % nr
* according to op.
*/
void
dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
{
......@@ -1193,7 +1246,7 @@ dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
nodconst(&n4, t, 0);
gmove(&n4, dx);
} else
gins(optoas(OFOR, t), N, N);
gins(optoas(OEXTEND, t), N, N);
cgen(nr, &n3);
} else {
cgen(nr, &n3);
......@@ -1202,7 +1255,7 @@ dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
nodconst(&n4, t, 0);
gmove(&n4, dx);
} else
gins(optoas(OFOR, t), N, N);
gins(optoas(OEXTEND, t), N, N);
}
gins(a, &n3, N);
regfree(&n3);
......@@ -1213,6 +1266,11 @@ dodiv(int op, Node *nl, Node *nr, Node *res, Node *ax, Node *dx)
gmove(dx, res);
}
/*
* generate division according to op, one of:
* res = nl / nr
* res = nl % nr
*/
void
cgen_div(int op, Node *nl, Node *nr, Node *res)
{
......@@ -1233,6 +1291,11 @@ cgen_div(int op, Node *nl, Node *nr, Node *res)
regfree(&dx);
}
/*
* generate shift according to op, one of:
* res = nl << nr
* res = nl >> nr
*/
void
cgen_shift(int op, Node *nl, Node *nr, Node *res)
{
......@@ -1293,45 +1356,51 @@ ret:
;
}
/*
* generate byte multiply:
* res = nl * nr
* no byte multiply instruction so have to do
* 16-bit multiply and take bottom half.
*/
void
cgen_bmul(int op, Node *nl, Node *nr, Node *res)
{
Node n1, n2, n3;
Node n1b, n2b, n1w, n2w;
Type *t;
int a;
if(nl->ullman >= nr->ullman) {
regalloc(&n1, nl->type, res);
cgen(nl, &n1);
regalloc(&n2, nr->type, N);
cgen(nr, &n2);
regalloc(&n1b, nl->type, res);
cgen(nl, &n1b);
regalloc(&n2b, nr->type, N);
cgen(nr, &n2b);
} else {
regalloc(&n2, nr->type, N);
cgen(nr, &n2);
regalloc(&n1, nl->type, res);
cgen(nl, &n1);
regalloc(&n2b, nr->type, N);
cgen(nr, &n2b);
regalloc(&n1b, nl->type, res);
cgen(nl, &n1b);
}
// copy to short registers
// copy from byte to short registers
t = types[TUINT16];
if(issigned[nl->type->etype])
t = types[TINT16];
regalloc(&n3, t, &n2);
cgen(&n2, &n3);
regfree(&n3);
regalloc(&n2w, t, &n2b);
cgen(&n2b, &n2w);
regalloc(&n3, t, &n1);
cgen(&n1, &n3);
regalloc(&n1w, t, &n1b);
cgen(&n1b, &n1w);
a = optoas(op, t);
gins(a, &n2, &n1);
cgen(&n3, &n1);
cgen(&n1, res);
regfree(&n1);
regfree(&n2);
regfree(&n3);
gins(a, &n2w, &n1w);
cgen(&n1w, &n1b);
cgen(&n1b, res);
regfree(&n1w);
regfree(&n2w);
regfree(&n1b);
regfree(&n2b);
}
void
......
src/cmd/6g/gg.h
View file @ 2d259c81
......@@ -145,7 +145,7 @@ void swgen(Node*);
void selgen(Node*);
Node* lookdot(Node*, Node*, int);
void inarggen(void);
void cgen_as(Node*, Node*, int);
void cgen_as(Node*, Node*);
void cgen_asop(Node*);
void cgen_ret(Node*);
void cgen_call(Node*, int);
......@@ -202,7 +202,6 @@ void ginit(void);
void gclean(void);
void regalloc(Node*, Type*, Node*);
void regfree(Node*);
void regsalloc(Node*, Type*); // replace w tmpvar
void regret(Node*, Type*);
Node* nodarg(Type*, int);
void nodreg(Node*, Type*, int);
......
src/cmd/6g/gsubr.c
View file @ 2d259c81
......@@ -42,6 +42,10 @@ clearp(Prog *p)
pcloc++;
}
/*
* generate and return proc with p->as = as,
* linked into program. pc is next instruction.
*/
Prog*
prog(int as)
{
......@@ -63,6 +67,10 @@ prog(int as)
return p;
}
/*
* generate a branch.
* t is ignored.
*/
Prog*
gbranch(int as, Type *t)
{
......@@ -74,6 +82,9 @@ gbranch(int as, Type *t)
return p;
}
/*
* patch previous branch to jump to to.
*/
void
patch(Prog *p, Prog *to)
{
......@@ -83,6 +94,9 @@ patch(Prog *p, Prog *to)
p->to.offset = to->loc;
}
/*
* start a new Prog list.
*/
Plist*
newplist(void)
{
......@@ -147,6 +161,11 @@ gclean(void)
yyerror("reg %R left allocated\n", i);
}
/*
* allocate register of type t, leave in n.
* if o != N, o is desired fixed register.
* caller must regfree(n).
*/
void
regalloc(Node *n, Type *t, Node *o)
{
......@@ -228,6 +247,9 @@ regret(Node *n, Type *t)
fatal("regret");
}
/*
* initialize n to be register r of type t.
*/
void
nodreg(Node *n, Type *t, int r)
{
......@@ -242,6 +264,9 @@ nodreg(Node *n, Type *t, int r)
n->type = t;
}
/*
* initialize n to be indirect of register r; n is type t.
*/
void
nodindreg(Node *n, Type *t, int r)
{
......@@ -314,6 +339,10 @@ nodconst(Node *n, Type *t, vlong v)
}
}
/*
* generate
* as $c, reg
*/
void
gconreg(int as, vlong c, int reg)
{
......@@ -326,6 +355,10 @@ gconreg(int as, vlong c, int reg)
#define CASE(a,b) (((a)<<16)|((b)<<0))
/*
* generate move:
* t = f
*/
void
gmove(Node *f, Node *t)
{
......@@ -842,12 +875,6 @@ gmove(Node *f, Node *t)
gins(a, f, t);
}
void
regsalloc(Node *f, Type *t)
{
fatal("regsalloc");
}
int
samaddr(Node *f, Node *t)
{
......@@ -864,6 +891,10 @@ samaddr(Node *f, Node *t)
return 0;
}
/*
* generate one instruction:
* as f, t
*/
Prog*
gins(int as, Node *f, Node *t)
{
......@@ -898,6 +929,10 @@ gins(int as, Node *f, Node *t)
return p;
}
/*
* generate code to compute n;
* make a refer to result.
*/
void
naddr(Node *n, Addr *a)
{
......@@ -1043,6 +1078,9 @@ naddr(Node *n, Addr *a)
}
}
/*
* return Axxx for Oxxx on type t.
*/
int
optoas(int op, Type *t)
{
......@@ -1545,15 +1583,15 @@ optoas(int op, Type *t)
a = ADIVQ;
break;
case CASE(OFOR, TINT16):
case CASE(OEXTEND, TINT16):
a = ACWD;
break;
case CASE(OFOR, TINT32):
case CASE(OEXTEND, TINT32):
a = ACDQ;
break;
case CASE(OFOR, TINT64):
case CASE(OEXTEND, TINT64):
a = ACQO;
break;
......@@ -1583,22 +1621,6 @@ isfat(Type *t)
return 0;
}
/*
* return unsigned(op)
* eg GT -> HS
*/
int
brunsigned(int a)
{
switch(a) {
case AJLT: return AJGE;
case AJGT: return AJLE;
case AJLE: return AJGT;
case AJGE: return AJLT;
}
return a;
}
/*
* return !(op)
* eg == <=> !=
......
src/cmd/gc/go.h
View file @ 2d259c81
......@@ -313,6 +313,8 @@ enum
OLITERAL, OREGISTER, OINDREG,
OCONV, OCOMP, OKEY,
OBAD,
OEXTEND, // 6g internal
OEND,
};
......
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