runtime: always incorporate hash seed at start of hash computation
Otherwise we can get predictable collisions.
R=golang-dev, dave, patrick, rsc
CC=golang-dev
https://golang.org/cl/7051043
diff --git a/src/pkg/runtime/alg.c b/src/pkg/runtime/alg.c
index c7424bc..ad85b43 100644
--- a/src/pkg/runtime/alg.c
+++ b/src/pkg/runtime/alg.c
@@ -19,13 +19,13 @@
uintptr hash;
b = a;
- hash = M0;
+ hash = M0 ^ *h;
while(s > 0) {
hash = (hash ^ *b) * M1;
b++;
s--;
}
- *h = (*h ^ hash) * M1;
+ *h = hash;
}
void
@@ -355,7 +355,7 @@
runtime·interhash(uintptr *h, uintptr s, void *a)
{
USED(s);
- *h = (*h ^ runtime·ifacehash(*(Iface*)a)) * M1;
+ *h = runtime·ifacehash(*(Iface*)a, *h ^ M0) * M1;
}
void
@@ -389,7 +389,7 @@
runtime·nilinterhash(uintptr *h, uintptr s, void *a)
{
USED(s);
- *h = (*h ^ runtime·efacehash(*(Eface*)a)) * M1;
+ *h = runtime·efacehash(*(Eface*)a, *h ^ M0) * M1;
}
void
diff --git a/src/pkg/runtime/iface.c b/src/pkg/runtime/iface.c
index 3a7c45f..370edff 100644
--- a/src/pkg/runtime/iface.c
+++ b/src/pkg/runtime/iface.c
@@ -546,10 +546,10 @@
}
static uintptr
-ifacehash1(void *data, Type *t)
+ifacehash1(void *data, Type *t, uintptr h)
{
Alg *alg;
- uintptr size, h;
+ uintptr size;
Eface err;
if(t == nil)
@@ -563,7 +563,6 @@
runtime·newErrorString(runtime·catstring(runtime·gostringnocopy((byte*)"hash of unhashable type "), *t->string), &err);
runtime·panic(err);
}
- h = 0;
if(size <= sizeof(data))
alg->hash(&h, size, &data);
else
@@ -572,17 +571,17 @@
}
uintptr
-runtime·ifacehash(Iface a)
+runtime·ifacehash(Iface a, uintptr h)
{
if(a.tab == nil)
- return 0;
- return ifacehash1(a.data, a.tab->type);
+ return h;
+ return ifacehash1(a.data, a.tab->type, h);
}
uintptr
-runtime·efacehash(Eface a)
+runtime·efacehash(Eface a, uintptr h)
{
- return ifacehash1(a.data, a.type);
+ return ifacehash1(a.data, a.type, h);
}
static bool
diff --git a/src/pkg/runtime/runtime.h b/src/pkg/runtime/runtime.h
index 0c941f8..a228b06 100644
--- a/src/pkg/runtime/runtime.h
+++ b/src/pkg/runtime/runtime.h
@@ -644,8 +644,8 @@
void runtime·mallocinit(void);
bool runtime·ifaceeq_c(Iface, Iface);
bool runtime·efaceeq_c(Eface, Eface);
-uintptr runtime·ifacehash(Iface);
-uintptr runtime·efacehash(Eface);
+uintptr runtime·ifacehash(Iface, uintptr);
+uintptr runtime·efacehash(Eface, uintptr);
void* runtime·malloc(uintptr size);
void runtime·free(void *v);
bool runtime·addfinalizer(void*, void(*fn)(void*), uintptr);
