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Commit 527ae57e authored by Russ Cox's avatar Russ Cox
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cmd/5g, cmd/8g: registerize small structs and arrays 

cmd/6g has been doing this for a long time.

Arrays are still problematic on 5g because the addressing
for t[0] where local var t has type [3]uintptr takes the address of t.
That's issue 8125.

Fixes #8123.

LGTM=josharian
R=josharian, dave
CC=golang-codereviews
https://golang.org/cl/102890046
parent 75b72b1b
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Inline Side-by-side
Showing with 147 additions and 6 deletions
src/cmd/5g/cgen.c
View file @ 527ae57e
......@@ -1635,7 +1635,10 @@ int
componentgen(Node *nr, Node *nl)
{
Node nodl, nodr, tmp;
Type *t;
int freel, freer;
vlong fldcount;
vlong loffset, roffset;
freel = 0;
freer = 0;
......@@ -1645,8 +1648,33 @@ componentgen(Node *nr, Node *nl)
goto no;
case TARRAY:
if(!isslice(nl->type))
t = nl->type;
// Slices are ok.
if(isslice(t))
break;
// Small arrays are ok.
if(t->bound > 0 && t->bound <= 3 && !isfat(t->type))
break;
goto no;
case TSTRUCT:
// Small structs with non-fat types are ok.
// Zero-sized structs are treated separately elsewhere.
fldcount = 0;
for(t=nl->type->type; t; t=t->down) {
if(isfat(t->type))
goto no;
if(t->etype != TFIELD)
fatal("componentgen: not a TFIELD: %lT", t);
fldcount++;
}
if(fldcount == 0 || fldcount > 4)
goto no;
break;
case TSTRING:
case TINTER:
break;
......@@ -1674,6 +1702,7 @@ componentgen(Node *nr, Node *nl)
freer = 1;
}
// nl and nr are 'cadable' which basically means they are names (variables) now.
// If they are the same variable, don't generate any code, because the
// VARDEF we generate will mark the old value as dead incorrectly.
......@@ -1683,8 +1712,25 @@ componentgen(Node *nr, Node *nl)
switch(nl->type->etype) {
case TARRAY:
// componentgen for arrays.
if(nl->op == ONAME)
gvardef(nl);
t = nl->type;
if(!isslice(t)) {
nodl.type = t->type;
nodr.type = nodl.type;
for(fldcount=0; fldcount < t->bound; fldcount++) {
if(nr == N)
clearslim(&nodl);
else
gmove(&nodr, &nodl);
nodl.xoffset += t->type->width;
nodr.xoffset += t->type->width;
}
goto yes;
}
// componentgen for slices.
nodl.xoffset += Array_array;
nodl.type = ptrto(nl->type->type);
......@@ -1759,6 +1805,31 @@ componentgen(Node *nr, Node *nl)
gmove(&nodr, &nodl);
goto yes;
case TSTRUCT:
if(nl->op == ONAME)
gvardef(nl);
loffset = nodl.xoffset;
roffset = nodr.xoffset;
// funarg structs may not begin at offset zero.
if(nl->type->etype == TSTRUCT && nl->type->funarg && nl->type->type)
loffset -= nl->type->type->width;
if(nr != N && nr->type->etype == TSTRUCT && nr->type->funarg && nr->type->type)
roffset -= nr->type->type->width;
for(t=nl->type->type; t; t=t->down) {
nodl.xoffset = loffset + t->width;
nodl.type = t->type;
if(nr == N)
clearslim(&nodl);
else {
nodr.xoffset = roffset + t->width;
nodr.type = nodl.type;
gmove(&nodr, &nodl);
}
}
goto yes;
}
no:
......
src/cmd/8g/cgen.c
View file @ 527ae57e
......@@ -1367,7 +1367,10 @@ int
componentgen(Node *nr, Node *nl)
{
Node nodl, nodr;
Type *t;
int freel, freer;
vlong fldcount;
vlong loffset, roffset;
freel = 0;
freer = 0;
......@@ -1377,8 +1380,33 @@ componentgen(Node *nr, Node *nl)
goto no;
case TARRAY:
if(!isslice(nl->type))
t = nl->type;
// Slices are ok.
if(isslice(t))
break;
// Small arrays are ok.
if(t->bound > 0 && t->bound <= 3 && !isfat(t->type))
break;
goto no;
case TSTRUCT:
// Small structs with non-fat types are ok.
// Zero-sized structs are treated separately elsewhere.
fldcount = 0;
for(t=nl->type->type; t; t=t->down) {
if(isfat(t->type))
goto no;
if(t->etype != TFIELD)
fatal("componentgen: not a TFIELD: %lT", t);
fldcount++;
}
if(fldcount == 0 || fldcount > 4)
goto no;
break;
case TSTRING:
case TINTER:
break;
......@@ -1399,7 +1427,7 @@ componentgen(Node *nr, Node *nl)
freer = 1;
}
}
// nl and nr are 'cadable' which basically means they are names (variables) now.
// If they are the same variable, don't generate any code, because the
// VARDEF we generate will mark the old value as dead incorrectly.
......@@ -1409,8 +1437,25 @@ componentgen(Node *nr, Node *nl)
switch(nl->type->etype) {
case TARRAY:
// componentgen for arrays.
if(nl->op == ONAME)
gvardef(nl);
t = nl->type;
if(!isslice(t)) {
nodl.type = t->type;
nodr.type = nodl.type;
for(fldcount=0; fldcount < t->bound; fldcount++) {
if(nr == N)
clearslim(&nodl);
else
gmove(&nodr, &nodl);
nodl.xoffset += t->type->width;
nodr.xoffset += t->type->width;
}
goto yes;
}
// componentgen for slices.
nodl.xoffset += Array_array;
nodl.type = ptrto(nl->type->type);
......@@ -1422,7 +1467,7 @@ componentgen(Node *nr, Node *nl)
gmove(&nodr, &nodl);
nodl.xoffset += Array_nel-Array_array;
nodl.type = types[TUINT32];
nodl.type = types[simtype[TUINT]];
if(nr != N) {
nodr.xoffset += Array_nel-Array_array;
......@@ -1432,7 +1477,7 @@ componentgen(Node *nr, Node *nl)
gmove(&nodr, &nodl);
nodl.xoffset += Array_cap-Array_nel;
nodl.type = types[TUINT32];
nodl.type = types[simtype[TUINT]];
if(nr != N) {
nodr.xoffset += Array_cap-Array_nel;
......@@ -1457,7 +1502,7 @@ componentgen(Node *nr, Node *nl)
gmove(&nodr, &nodl);
nodl.xoffset += Array_nel-Array_array;
nodl.type = types[TUINT32];
nodl.type = types[simtype[TUINT]];
if(nr != N) {
nodr.xoffset += Array_nel-Array_array;
......@@ -1492,6 +1537,31 @@ componentgen(Node *nr, Node *nl)
gmove(&nodr, &nodl);
goto yes;
case TSTRUCT:
if(nl->op == ONAME)
gvardef(nl);
loffset = nodl.xoffset;
roffset = nodr.xoffset;
// funarg structs may not begin at offset zero.
if(nl->type->etype == TSTRUCT && nl->type->funarg && nl->type->type)
loffset -= nl->type->type->width;
if(nr != N && nr->type->etype == TSTRUCT && nr->type->funarg && nr->type->type)
roffset -= nr->type->type->width;
for(t=nl->type->type; t; t=t->down) {
nodl.xoffset = loffset + t->width;
nodl.type = t->type;
if(nr == N)
clearslim(&nodl);
else {
nodr.xoffset = roffset + t->width;
nodr.type = nodl.type;
gmove(&nodr, &nodl);
}
}
goto yes;
}
no:
......
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