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cmd/gc: inline copy in frontend to call memmove directly.

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A new node type OSPTR is added to refer to the data pointer of
strings and slices in a simple way during walk(). It will be
useful for future work on simplification of slice arithmetic.

benchmark                  old ns/op    new ns/op    delta
BenchmarkCopy1Byte                 9            8  -13.98%
BenchmarkCopy2Byte                14            8  -40.49%
BenchmarkCopy4Byte                13            8  -35.04%
BenchmarkCopy8Byte                13            8  -37.10%
BenchmarkCopy12Byte               14           12  -15.38%
BenchmarkCopy16Byte               14           12  -17.24%
BenchmarkCopy32Byte               19           14  -27.32%
BenchmarkCopy128Byte              31           26  -15.29%
BenchmarkCopy1024Byte            100           92   -7.50%
BenchmarkCopy1String              10            7  -28.99%
BenchmarkCopy2String              10            7  -28.06%
BenchmarkCopy4String              10            8  -22.69%
BenchmarkCopy8String              10            8  -23.30%
BenchmarkCopy12String             11           11   -5.88%
BenchmarkCopy16String             11           11   -5.08%
BenchmarkCopy32String             15           14   -6.58%
BenchmarkCopy128String            28           25  -10.60%
BenchmarkCopy1024String           95           95   +0.53%

R=golang-dev, bradfitz, cshapiro, dave, daniel.morsing, rsc, khr, khr
CC=golang-dev
https://golang.org/cl/9101048
This commit is contained in:
Rémy Oudompheng 2013-09-12 00:15:28 +02:00
parent 6d47de2f40
commit ff416a3f19
13 changed files with 210 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/cmd/5g/cgen.c
View File

@ -79,6 +79,7 @@ cgen(Node *n, Node *res)
// can't do in walk because n->left->addable
// changes if n->left is an escaping local variable.
switch(n->op) {
case OSPTR:
case OLEN:
if(isslice(n->left->type) || istype(n->left->type, TSTRING))
n->addable = n->left->addable;
@ -317,6 +318,22 @@ cgen(Node *n, Node *res)
regfree(&n1);
break;
case OSPTR:
// pointer is the first word of string or slice.
if(isconst(nl, CTSTR)) {
regalloc(&n1, types[tptr], res);
p1 = gins(AMOVW, N, &n1);
datastring(nl->val.u.sval->s, nl->val.u.sval->len, &p1->from);
gmove(&n1, res);
regfree(&n1);
break;
}
igen(nl, &n1, res);
n1.type = n->type;
gmove(&n1, res);
regfree(&n1);
break;
case OLEN:
if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
// map has len in the first 32-bit word.

10
src/cmd/5g/gsubr.c
View File

@ -1361,6 +1361,16 @@ naddr(Node *n, Addr *a, int canemitcode)
break; // len(nil)
break;
case OSPTR:
// pointer in a string or slice
naddr(n->left, a, canemitcode);
if(a->type == D_CONST && a->offset == 0)
break; // ptr(nil)
a->etype = simtype[TUINTPTR];
a->offset += Array_array;
a->width = widthptr;
break;
case OLEN:
// len of string or slice
naddr(n->left, a, canemitcode);

17
src/cmd/6g/cgen.c
View File

@ -136,6 +136,7 @@ cgen(Node *n, Node *res)
// can't do in walk because n->left->addable
// changes if n->left is an escaping local variable.
switch(n->op) {
case OSPTR:
case OLEN:
if(isslice(n->left->type) || istype(n->left->type, TSTRING))
n->addable = n->left->addable;
@ -314,6 +315,22 @@ cgen(Node *n, Node *res)
regfree(&n1);
break;
case OSPTR:
// pointer is the first word of string or slice.
if(isconst(nl, CTSTR)) {
regalloc(&n1, types[tptr], res);
p1 = gins(ALEAQ, N, &n1);
datastring(nl->val.u.sval->s, nl->val.u.sval->len, &p1->from);
gmove(&n1, res);
regfree(&n1);
break;
}
igen(nl, &n1, res);
n1.type = n->type;
gmove(&n1, res);
regfree(&n1);
break;
case OLEN:
if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
// map and chan have len in the first int-sized word.

11
src/cmd/6g/gsubr.c
View File

@ -562,6 +562,7 @@ ismem(Node *n)
{
switch(n->op) {
case OITAB:
case OSPTR:
case OLEN:
case OCAP:
case OINDREG:
@ -1267,6 +1268,16 @@ naddr(Node *n, Addr *a, int canemitcode)
a->width = widthptr;
break;
case OSPTR:
// pointer in a string or slice
naddr(n->left, a, canemitcode);
if(a->type == D_CONST && a->offset == 0)
break; // ptr(nil)
a->etype = simtype[TUINTPTR];
a->offset += Array_array;
a->width = widthptr;
break;
case OLEN:
// len of string or slice
naddr(n->left, a, canemitcode);

17
src/cmd/8g/cgen.c
View File

@ -109,6 +109,7 @@ cgen(Node *n, Node *res)
// can't do in walk because n->left->addable
// changes if n->left is an escaping local variable.
switch(n->op) {
case OSPTR:
case OLEN:
if(isslice(n->left->type) || istype(n->left->type, TSTRING))
n->addable = n->left->addable;
@ -288,6 +289,22 @@ cgen(Node *n, Node *res)
regfree(&n1);
break;
case OSPTR:
// pointer is the first word of string or slice.
if(isconst(nl, CTSTR)) {
regalloc(&n1, types[tptr], res);
p1 = gins(ALEAL, N, &n1);
datastring(nl->val.u.sval->s, nl->val.u.sval->len, &p1->from);
gmove(&n1, res);
regfree(&n1);
break;
}
igen(nl, &n1, res);
n1.type = n->type;
gmove(&n1, res);
regfree(&n1);
break;
case OLEN:
if(istype(nl->type, TMAP) || istype(nl->type, TCHAN)) {
// map has len in the first 32-bit word.

11
src/cmd/8g/gsubr.c
View File

@ -1157,6 +1157,7 @@ ismem(Node *n)
{
switch(n->op) {
case OITAB:
case OSPTR:
case OLEN:
case OCAP:
case OINDREG:
@ -2321,6 +2322,16 @@ naddr(Node *n, Addr *a, int canemitcode)
a->width = widthptr;
break;
case OSPTR:
// pointer in a string or slice
naddr(n->left, a, canemitcode);
if(a->type == D_CONST && a->offset == 0)
break; // ptr(nil)
a->etype = simtype[TUINTPTR];
a->offset += Array_array;
a->width = widthptr;
break;
case OLEN:
// len of string or slice
naddr(n->left, a, canemitcode);

1
src/cmd/gc/builtin.c
View File

@ -94,6 +94,7 @@ char *runtimeimport =
"func @\"\".block ()\n"
"func @\"\".makeslice (@\"\".typ·2 *byte, @\"\".nel·3 int64, @\"\".cap·4 int64) (@\"\".ary·1 []any)\n"
"func @\"\".growslice (@\"\".typ·2 *byte, @\"\".old·3 []any, @\"\".n·4 int64) (@\"\".ary·1 []any)\n"
"func @\"\".memmove (@\"\".to·1 *any, @\"\".frm·2 *any, @\"\".length·3 uintptr)\n"
"func @\"\".memequal (@\"\".eq·1 *bool, @\"\".size·2 uintptr, @\"\".x·3 *any, @\"\".y·4 *any)\n"
"func @\"\".memequal8 (@\"\".eq·1 *bool, @\"\".size·2 uintptr, @\"\".x·3 *any, @\"\".y·4 *any)\n"
"func @\"\".memequal16 (@\"\".eq·1 *bool, @\"\".size·2 uintptr, @\"\".x·3 *any, @\"\".y·4 *any)\n"

1
src/cmd/gc/go.h
View File

@ -577,6 +577,7 @@ enum
OINLCALL, // intermediary representation of an inlined call.
OEFACE, // itable and data words of an empty-interface value.
OITAB, // itable word of an interface value.
OSPTR, // base pointer of a slice or string.
OCLOSUREVAR, // variable reference at beginning of closure function
OCFUNC, // reference to c function pointer (not go func value)
OCHECKNIL, // emit code to ensure pointer/interface not nil

1
src/cmd/gc/racewalk.c
View File

@ -238,6 +238,7 @@ racewalknode(Node **np, NodeList **init, int wr, int skip)
callinstr(&n, init, wr, skip);
goto ret;
case OSPTR:
case OLEN:
case OCAP:
racewalknode(&n->left, init, 0, 0);

1
src/cmd/gc/runtime.go
View File

@ -124,6 +124,7 @@ func block()
func makeslice(typ *byte, nel int64, cap int64) (ary []any)
func growslice(typ *byte, old []any, n int64) (ary []any)
func memmove(to *any, frm *any, length uintptr)
func memequal(eq *bool, size uintptr, x, y *any)
func memequal8(eq *bool, size uintptr, x, y *any)

13
src/cmd/gc/typecheck.c
View File

@ -1573,6 +1573,19 @@ reswitch:
n->type = ptrto(types[TUINTPTR]);
goto ret;
case OSPTR:
ok |= Erv;
typecheck(&n->left, Erv);
if((t = n->left->type) == T)
goto error;
if(!isslice(t) && t->etype != TSTRING)
fatal("OSPTR of %T", t);
if(t->etype == TSTRING)
n->type = ptrto(types[TUINT8]);
else
n->type = ptrto(t->type);
goto ret;
case OCLOSUREVAR:
ok |= Erv;
goto ret;

60
src/cmd/gc/walk.c
View File

@ -21,6 +21,7 @@ static NodeList* reorder3(NodeList*);
static Node* addstr(Node*, NodeList**);
static Node* appendslice(Node*, NodeList**);
static Node* append(Node*, NodeList**);
static Node* copyany(Node*, NodeList**);
static Node* sliceany(Node*, NodeList**);
static void walkcompare(Node**, NodeList**);
static void walkrotate(Node**);
@ -174,6 +175,8 @@ walkstmt(Node **np)
n->ninit = nil;
walkexpr(&n, &init);
addinit(&n, init);
if((*np)->op == OCOPY && n->op == OCONVNOP)
n->op = OEMPTY; // don't leave plain values as statements.
break;
case OBREAK:
@ -432,6 +435,7 @@ walkexpr(Node **np, NodeList **init)
walkexpr(&n->right, init);
goto ret;
case OSPTR:
case OITAB:
walkexpr(&n->left, init);
goto ret;
@ -1243,6 +1247,7 @@ walkexpr(Node **np, NodeList **init)
goto ret;
case OCOPY:
if(flag_race) {
if(n->right->type->etype == TSTRING)
fn = syslook("slicestringcopy", 1);
else
@ -1253,6 +1258,9 @@ walkexpr(Node **np, NodeList **init)
n->left, n->right,
nodintconst(n->left->type->type->width));
goto ret;
}
n = copyany(n, init);
goto ret;
case OCLOSE:
// cannot use chanfn - closechan takes any, not chan any
@ -2618,6 +2626,58 @@ append(Node *n, NodeList **init)
return ns;
}
// Lower copy(a, b) to a memmove call.
//
// init {
// n := len(a)
// if n > len(b) { n = len(b) }
// memmove(a.ptr, b.ptr, n*sizeof(elem(a)))
// }
// n;
//
// Also works if b is a string.
//
static Node*
copyany(Node *n, NodeList **init)
{
Node *nl, *nr, *nfrm, *nto, *nif, *nlen, *nwid, *fn;
NodeList *l;
walkexpr(&n->left, init);
walkexpr(&n->right, init);
nl = temp(n->left->type);
nr = temp(n->right->type);
l = nil;
l = list(l, nod(OAS, nl, n->left));
l = list(l, nod(OAS, nr, n->right));
nfrm = nod(OSPTR, nr, N);
nto = nod(OSPTR, nl, N);
nlen = temp(types[TINT]);
// n = len(to)
l = list(l, nod(OAS, nlen, nod(OLEN, nl, N)));
// if n > len(frm) { n = len(frm) }
nif = nod(OIF, N, N);
nif->ntest = nod(OGT, nlen, nod(OLEN, nr, N));
nif->nbody = list(nif->nbody,
nod(OAS, nlen, nod(OLEN, nr, N)));
l = list(l, nif);
// Call memmove.
fn = syslook("memmove", 1);
argtype(fn, nl->type->type);
argtype(fn, nl->type->type);
nwid = temp(types[TUINTPTR]);
l = list(l, nod(OAS, nwid, conv(nlen, types[TUINTPTR])));
nwid = nod(OMUL, nwid, nodintconst(nl->type->type->width));
l = list(l, mkcall1(fn, T, init, nto, nfrm, nwid));
typechecklist(l, Etop);
walkstmtlist(l);
*init = concat(*init, l);
return nlen;
}
// Generate frontend part for OSLICE[3][ARR|STR]
//

40
src/pkg/runtime/append_test.go
View File

@ -129,3 +129,43 @@ func TestAppendOverlap(t *testing.T) {
t.Errorf("overlap failed: got %q want %q", got, want)
}
}
func benchmarkCopySlice(b *testing.B, l int) {
s := make([]byte, l)
buf := make([]byte, 4096)
var n int
for i := 0; i < b.N; i++ {
n = copy(buf, s)
}
b.SetBytes(int64(n))
}
func benchmarkCopyStr(b *testing.B, l int) {
s := string(make([]byte, l))
buf := make([]byte, 4096)
var n int
for i := 0; i < b.N; i++ {
n = copy(buf, s)
}
b.SetBytes(int64(n))
}
func BenchmarkCopy1Byte(b *testing.B) { benchmarkCopySlice(b, 1) }
func BenchmarkCopy2Byte(b *testing.B) { benchmarkCopySlice(b, 2) }
func BenchmarkCopy4Byte(b *testing.B) { benchmarkCopySlice(b, 4) }
func BenchmarkCopy8Byte(b *testing.B) { benchmarkCopySlice(b, 8) }
func BenchmarkCopy12Byte(b *testing.B) { benchmarkCopySlice(b, 12) }
func BenchmarkCopy16Byte(b *testing.B) { benchmarkCopySlice(b, 16) }
func BenchmarkCopy32Byte(b *testing.B) { benchmarkCopySlice(b, 32) }
func BenchmarkCopy128Byte(b *testing.B) { benchmarkCopySlice(b, 128) }
func BenchmarkCopy1024Byte(b *testing.B) { benchmarkCopySlice(b, 1024) }
func BenchmarkCopy1String(b *testing.B) { benchmarkCopyStr(b, 1) }
func BenchmarkCopy2String(b *testing.B) { benchmarkCopyStr(b, 2) }
func BenchmarkCopy4String(b *testing.B) { benchmarkCopyStr(b, 4) }
func BenchmarkCopy8String(b *testing.B) { benchmarkCopyStr(b, 8) }
func BenchmarkCopy12String(b *testing.B) { benchmarkCopyStr(b, 12) }
func BenchmarkCopy16String(b *testing.B) { benchmarkCopyStr(b, 16) }
func BenchmarkCopy32String(b *testing.B) { benchmarkCopyStr(b, 32) }
func BenchmarkCopy128String(b *testing.B) { benchmarkCopyStr(b, 128) }
func BenchmarkCopy1024String(b *testing.B) { benchmarkCopyStr(b, 1024) }