gc, runtime: handle floating point map keys

Fixes #2609.

R=ken2
CC=golang-dev
https://golang.org/cl/5572069

src/cmd/gc/go.h

@@ -57,6 +57,10 @@ enum
 	AINTER,
 	ANILINTER,
 	ASLICE,
+	AFLOAT32,
+	AFLOAT64,
+	ACPLX64,
+	ACPLX128,
 
 	BADWIDTH	= -1000000000,
 };

src/cmd/gc/subr.c

@@ -515,23 +515,31 @@ algtype1(Type *t, Type **bad)
 	case TINT:
 	case TUINT:
 	case TUINTPTR:
-	case TCOMPLEX64:
-	case TCOMPLEX128:
-	case TFLOAT32:
-	case TFLOAT64:
 	case TBOOL:
 	case TPTR32:
 	case TPTR64:
 	case TCHAN:
 	case TUNSAFEPTR:
 		return AMEM;
-	
+
 	case TFUNC:
 	case TMAP:
 		if(bad)
 			*bad = t;
 		return ANOEQ;
 
+	case TFLOAT32:
+		return AFLOAT32;
+
+	case TFLOAT64:
+		return AFLOAT64;
+
+	case TCOMPLEX64:
+		return ACPLX64;
+
+	case TCOMPLEX128:
+		return ACPLX128;
+
 	case TSTRING:
 		return ASTRING;
 	
@@ -2511,6 +2519,18 @@ hashfor(Type *t)
 	case ASTRING:
 		sym = pkglookup("strhash", runtimepkg);
 		break;
+	case AFLOAT32:
+		sym = pkglookup("f32hash", runtimepkg);
+		break;
+	case AFLOAT64:
+		sym = pkglookup("f64hash", runtimepkg);
+		break;
+	case ACPLX64:
+		sym = pkglookup("c64hash", runtimepkg);
+		break;
+	case ACPLX128:
+		sym = pkglookup("c128hash", runtimepkg);
+		break;
 	default:
 		sym = typesymprefix(".hash", t);
 		break;
@@ -2537,7 +2557,7 @@ genhash(Sym *sym, Type *t)
 	Node *hashel;
 	Type *first, *t1;
 	int old_safemode;
-	int64 size;
+	int64 size, mul;
 
 	if(debug['r'])
 		print("genhash %S %T\n", sym, t);
@@ -2594,6 +2614,17 @@ genhash(Sym *sym, Type *t)
 					nod(OLSH, nod(OIND, nh, N), nodintconst(3)),
 					nod(ORSH, nod(OIND, nh, N), nodintconst(widthptr*8-3)))));
 
+		// *h *= mul
+		// Same multipliers as in runtime.memhash.
+		if(widthptr == 4)
+			mul = 3267000013LL;
+		else
+			mul = 23344194077549503LL;
+		n->nbody = list(n->nbody,
+			nod(OAS,
+				nod(OIND, nh, N),
+				nod(OMUL, nod(OIND, nh, N), nodintconst(mul))));
+
 		// hashel(h, sizeof(p[i]), &p[i])
 		call = nod(OCALL, hashel, N);
 		call->list = list(call->list, nh);

src/pkg/runtime/alg.c

@@ -197,6 +197,106 @@ runtime·memcopy128(uintptr s, void *a, void *b)
 	((uint64*)a)[1] = ((uint64*)b)[1];
 }
 
+void
+runtime·f32equal(bool *eq, uintptr s, void *a, void *b)
+{
+	USED(s);
+	*eq = *(float32*)a == *(float32*)b;
+}
+
+void
+runtime·f64equal(bool *eq, uintptr s, void *a, void *b)
+{
+	USED(s);
+	*eq = *(float64*)a == *(float64*)b;
+}
+
+void
+runtime·c64equal(bool *eq, uintptr s, void *a, void *b)
+{	
+	Complex64 *ca, *cb;
+	
+	USED(s);
+	ca = a;
+	cb = b;
+	*eq = ca->real == cb->real && ca->imag == cb->imag;
+}
+
+void
+runtime·c128equal(bool *eq, uintptr s, void *a, void *b)
+{	
+	Complex128 *ca, *cb;
+	
+	USED(s);
+	ca = a;
+	cb = b;
+	*eq = ca->real == cb->real && ca->imag == cb->imag;
+}
+
+// NOTE: Because NaN != NaN, a map can contain any
+// number of (mostly useless) entries keyed with NaNs.
+// To avoid long hash chains, we assign a random number
+// as the hash value for a NaN.
+
+void
+runtime·f32hash(uintptr *h, uintptr s, void *a)
+{
+	uintptr hash;
+	float32 f;
+
+	USED(s);
+	f = *(float32*)a;
+	if(f == 0)
+		hash = 0;  // +0, -0
+	else if(f != f)
+		hash = runtime·fastrand1();  // any kind of NaN
+	else
+		hash = *(uint32*)a;
+	*h ^= (*h ^ hash ^ 2860486313U) * 3267000013U;
+}
+
+void
+runtime·f64hash(uintptr *h, uintptr s, void *a)
+{
+	uintptr hash;
+	float64 f;
+	uint64 u;
+
+	USED(s);
+	f = *(float32*)a;
+	if(f == 0)
+		hash = 0;	// +0, -0
+	else if(f != f)
+		hash = runtime·fastrand1();  // any kind of NaN
+	else {
+		u = *(uint64*)a;
+		if(sizeof(uintptr) == 4)
+			hash = ((uint32)(u>>32) ^ 2860486313) * (uint32)u;
+		else
+			hash = u;
+	}
+	if(sizeof(uintptr) == 4)
+		*h = (*h ^ hash ^ 2860486313U) * 3267000013U;
+	else
+		*h = (*h ^ hash ^ 33054211828000289ULL) * 23344194077549503ULL;
+}
+
+void
+runtime·c64hash(uintptr *h, uintptr s, void *a)
+{
+	USED(s);
+	runtime·f32hash(h, 0, a);
+	runtime·f32hash(h, 0, (float32*)a+1);
+}
+
+void
+runtime·c128hash(uintptr *h, uintptr s, void *a)
+{
+	USED(s);
+	runtime·f64hash(h, 0, a);
+	runtime·f64hash(h, 0, (float64*)a+1);
+}
+
 void
 runtime·slicecopy(uintptr s, void *a, void *b)
 {
@@ -349,6 +449,10 @@ runtime·algarray[] =
 [AINTER]	{ runtime·interhash, runtime·interequal, runtime·interprint, runtime·intercopy },
 [ANILINTER]	{ runtime·nilinterhash, runtime·nilinterequal, runtime·nilinterprint, runtime·nilintercopy },
 [ASLICE]	{ runtime·nohash, runtime·noequal, runtime·memprint, runtime·slicecopy },
+[AFLOAT32]	{ runtime·f32hash, runtime·f32equal, runtime·memprint, runtime·memcopy },
+[AFLOAT64]	{ runtime·f64hash, runtime·f64equal, runtime·memprint, runtime·memcopy },
+[ACPLX64]	{ runtime·c64hash, runtime·c64equal, runtime·memprint, runtime·memcopy },
+[ACPLX128]	{ runtime·c128hash, runtime·c128equal, runtime·memprint, runtime·memcopy },
 [AMEM0]		{ runtime·memhash, runtime·memequal0, runtime·memprint, runtime·memcopy0 },
 [AMEM8]		{ runtime·memhash, runtime·memequal8, runtime·memprint, runtime·memcopy8 },
 [AMEM16]	{ runtime·memhash, runtime·memequal16, runtime·memprint, runtime·memcopy16 },

src/pkg/runtime/runtime.c

@@ -278,8 +278,8 @@ runtime·check(void)
 	uint32 f;
 	int64 g;
 	uint64 h;
-	float32 i;
-	float64 j;
+	float32 i, i1;
+	float64 j, j1;
 	void* k;
 	uint16* l;
 	struct x1 {
@@ -319,6 +319,30 @@ runtime·check(void)
 	if(z != 4)
 		runtime·throw("cas4");
 
+	*(uint64*)&j = ~0ULL;
+	if(j == j)
+		runtime·throw("float64nan");
+	if(!(j != j))
+		runtime·throw("float64nan1");
+
+	*(uint64*)&j1 = ~1ULL;
+	if(j == j1)
+		runtime·throw("float64nan2");
+	if(!(j != j1))
+		runtime·throw("float64nan3");
+
+	*(uint32*)&i = ~0UL;
+	if(i == i)
+		runtime·throw("float32nan");
+	if(!(i != i))
+		runtime·throw("float32nan1");
+
+	*(uint32*)&i1 = ~1UL;
+	if(i == i1)
+		runtime·throw("float32nan2");
+	if(!(i != i1))
+		runtime·throw("float32nan3");
+
 	runtime·initsig(0);
 }
 

src/pkg/runtime/runtime.h

@@ -375,6 +375,10 @@ enum
 	AINTER,
 	ANILINTER,
 	ASLICE,
+	AFLOAT32,
+	AFLOAT64,
+	ACPLX64,
+	ACPLX128,
 	Amax
 };
 typedef	struct	Alg		Alg;

test/map.go

@@ -8,6 +8,7 @@ package main
 
 import (
 	"fmt"
+	"math"
 	"strconv"
 )
 
@@ -488,4 +489,160 @@ func main() {
 	for _, _ = range mnil {
 		panic("range mnil")
 	}
+
+	testfloat()
+}
+
+func testfloat() {
+	// Test floating point numbers in maps.
+	// Two map keys refer to the same entry if the keys are ==.
+	// The special cases, then, are that +0 == -0 and that NaN != NaN.
+
+	{
+		var (
+			pz   = float32(0)
+			nz   = math.Float32frombits(1 << 31)
+			nana = float32(math.NaN())
+			nanb = math.Float32frombits(math.Float32bits(nana) ^ 2)
+		)
+
+		m := map[float32]string{
+			pz:   "+0",
+			nana: "NaN",
+			nanb: "NaN",
+		}
+		if m[pz] != "+0" {
+			fmt.Println("float32 map cannot read back m[+0]:", m[pz])
+		}
+		if m[nz] != "+0" {
+			fmt.Println("float32 map does not treat", pz, "and", nz, "as equal for read")
+			fmt.Println("float32 map does not treat -0 and +0 as equal for read")
+		}
+		m[nz] = "-0"
+		if m[pz] != "-0" {
+			fmt.Println("float32 map does not treat -0 and +0 as equal for write")
+		}
+		if _, ok := m[nana]; ok {
+			fmt.Println("float32 map allows NaN lookup (a)")
+		}
+		if _, ok := m[nanb]; ok {
+			fmt.Println("float32 map allows NaN lookup (b)")
+		}
+		if len(m) != 3 {
+			fmt.Println("float32 map should have 3 entries:", m)
+		}
+		m[nana] = "NaN"
+		m[nanb] = "NaN"
+		if len(m) != 5 {
+			fmt.Println("float32 map should have 5 entries:", m)
+		}
+	}
+
+	{
+		var (
+			pz   = float64(0)
+			nz   = math.Float64frombits(1 << 63)
+			nana = float64(math.NaN())
+			nanb = math.Float64frombits(math.Float64bits(nana) ^ 2)
+		)
+
+		m := map[float64]string{
+			pz:   "+0",
+			nana: "NaN",
+			nanb: "NaN",
+		}
+		if m[nz] != "+0" {
+			fmt.Println("float64 map does not treat -0 and +0 as equal for read")
+		}
+		m[nz] = "-0"
+		if m[pz] != "-0" {
+			fmt.Println("float64 map does not treat -0 and +0 as equal for write")
+		}
+		if _, ok := m[nana]; ok {
+			fmt.Println("float64 map allows NaN lookup (a)")
+		}
+		if _, ok := m[nanb]; ok {
+			fmt.Println("float64 map allows NaN lookup (b)")
+		}
+		if len(m) != 3 {
+			fmt.Println("float64 map should have 3 entries:", m)
+		}
+		m[nana] = "NaN"
+		m[nanb] = "NaN"
+		if len(m) != 5 {
+			fmt.Println("float64 map should have 5 entries:", m)
+		}
+	}
+
+	{
+		var (
+			pz   = complex64(0)
+			nz   = complex(0, math.Float32frombits(1<<31))
+			nana = complex(5, float32(math.NaN()))
+			nanb = complex(5, math.Float32frombits(math.Float32bits(float32(math.NaN()))^2))
+		)
+
+		m := map[complex64]string{
+			pz:   "+0",
+			nana: "NaN",
+			nanb: "NaN",
+		}
+		if m[nz] != "+0" {
+			fmt.Println("complex64 map does not treat -0 and +0 as equal for read")
+		}
+		m[nz] = "-0"
+		if m[pz] != "-0" {
+			fmt.Println("complex64 map does not treat -0 and +0 as equal for write")
+		}
+		if _, ok := m[nana]; ok {
+			fmt.Println("complex64 map allows NaN lookup (a)")
+		}
+		if _, ok := m[nanb]; ok {
+			fmt.Println("complex64 map allows NaN lookup (b)")
+		}
+		if len(m) != 3 {
+			fmt.Println("complex64 map should have 3 entries:", m)
+		}
+		m[nana] = "NaN"
+		m[nanb] = "NaN"
+		if len(m) != 5 {
+			fmt.Println("complex64 map should have 5 entries:", m)
+		}
+	}
+
+	{
+		var (
+			pz   = complex128(0)
+			nz   = complex(0, math.Float64frombits(1<<63))
+			nana = complex(5, float64(math.NaN()))
+			nanb = complex(5, math.Float64frombits(math.Float64bits(float64(math.NaN()))^2))
+		)
+
+		m := map[complex128]string{
+			pz:   "+0",
+			nana: "NaN",
+			nanb: "NaN",
+		}
+		if m[nz] != "+0" {
+			fmt.Println("complex128 map does not treat -0 and +0 as equal for read")
+		}
+		m[nz] = "-0"
+		if m[pz] != "-0" {
+			fmt.Println("complex128 map does not treat -0 and +0 as equal for write")
+		}
+		if _, ok := m[nana]; ok {
+			fmt.Println("complex128 map allows NaN lookup (a)")
+		}
+		if _, ok := m[nanb]; ok {
+			fmt.Println("complex128 map allows NaN lookup (b)")
+		}
+		if len(m) != 3 {
+			fmt.Println("complex128 map should have 3 entries:", m)
+		}
+		m[nana] = "NaN"
+		m[nanb] = "NaN"
+		if len(m) != 5 {
+			fmt.Println("complex128 map should have 5 entries:", m)
+		}
+	}
 }