Switch our Python set implementation to use a llvm::DenseSet

src/runtime/set.cpp

@@ -29,15 +29,9 @@ void BoxedSet::gcHandler(GCVisitor* v, Box* b) {
     Box::gcHandler(v, b);
 
     BoxedSet* s = (BoxedSet*)b;
-
-    // This feels like a cludge, but we need to find anything that
-    // the unordered_map might have allocated.
-    // Another way to handle this would be to rt_alloc the unordered_map
-    // as well, though that incurs extra memory dereferences which would
-    // be nice to avoid.
-    void** start = (void**)&s->s;
-    void** end = start + (sizeof(s->s) / 8);
-    v->visitPotentialRange(start, end);
+    for (auto&& p : s->s) {
+        v->visit(p.value);
+    }
 }
 
 namespace set {
@@ -54,7 +48,7 @@ public:
     bool hasNext() { return it != s->s.end(); }
 
     Box* next() {
-        Box* rtn = *it;
+        Box* rtn = it->value;
         ++it;
         return rtn;
     }
@@ -136,13 +130,13 @@ static Box* _setRepr(BoxedSet* self, const char* type_name) {
         chars.push_back('[');
 
         bool first = true;
-        for (Box* elt : self->s) {
+        for (auto&& elt : self->s) {
 
             if (!first) {
                 chars.push_back(',');
                 chars.push_back(' ');
             }
-            BoxedString* str = static_cast<BoxedString*>(repr(elt));
+            BoxedString* str = static_cast<BoxedString*>(repr(elt.value));
             chars.insert(chars.end(), str->s().begin(), str->s().end());
 
             first = false;
@@ -173,10 +167,10 @@ Box* setOrSet(BoxedSet* lhs, BoxedSet* rhs) {
 
     BoxedSet* rtn = new (lhs->cls) BoxedSet();
 
-    for (Box* elt : lhs->s) {
+    for (auto&& elt : lhs->s) {
         rtn->s.insert(elt);
     }
-    for (Box* elt : rhs->s) {
+    for (auto&& elt : rhs->s) {
         rtn->s.insert(elt);
     }
     return rtn;
@@ -188,7 +182,7 @@ Box* setAndSet(BoxedSet* lhs, BoxedSet* rhs) {
 
     BoxedSet* rtn = new (lhs->cls) BoxedSet();
 
-    for (Box* elt : lhs->s) {
+    for (auto&& elt : lhs->s) {
         if (rhs->s.count(elt))
             rtn->s.insert(elt);
     }
@@ -201,7 +195,7 @@ Box* setSubSet(BoxedSet* lhs, BoxedSet* rhs) {
 
     BoxedSet* rtn = new (lhs->cls) BoxedSet();
 
-    for (Box* elt : lhs->s) {
+    for (auto&& elt : lhs->s) {
         // TODO if len(rhs) << len(lhs), it might be more efficient
         // to delete the elements of rhs from lhs?
         if (rhs->s.count(elt) == 0)
@@ -216,12 +210,12 @@ Box* setXorSet(BoxedSet* lhs, BoxedSet* rhs) {
 
     BoxedSet* rtn = new (lhs->cls) BoxedSet();
 
-    for (Box* elt : lhs->s) {
+    for (auto&& elt : lhs->s) {
         if (rhs->s.count(elt) == 0)
             rtn->s.insert(elt);
     }
 
-    for (Box* elt : rhs->s) {
+    for (auto&& elt : rhs->s) {
         if (lhs->s.count(elt) == 0)
             rtn->s.insert(elt);
     }
@@ -447,7 +441,7 @@ Box* setPop(BoxedSet* self) {
         raiseExcHelper(KeyError, "pop from an empty set");
 
     auto it = self->s.begin();
-    Box* rtn = *it;
+    Box* rtn = it->value;
     self->s.erase(it);
     return rtn;
 }
@@ -489,10 +483,8 @@ Box* setHash(BoxedSet* self) {
     RELEASE_ASSERT(isSubclass(self->cls, frozenset_cls), "");
 
     int64_t rtn = 1927868237L;
-    for (Box* e : self->s) {
-        BoxedInt* h = hash(e);
-        assert(PyInt_Check(h));
-        rtn ^= h->n + 0x9e3779b9 + (rtn << 6) + (rtn >> 2);
+    for (auto&& e : self->s) {
+        rtn ^= e.hash + 0x9e3779b9 + (rtn << 6) + (rtn >> 2);
     }
 
     return boxInt(rtn);

src/runtime/set.h

@@ -15,7 +15,7 @@
 #ifndef PYSTON_RUNTIME_SET_H
 #define PYSTON_RUNTIME_SET_H
 
-#include <unordered_set>
+#include "llvm/ADT/DenseSet.h"
 
 #include "core/types.h"
 #include "runtime/types.h"
@@ -29,7 +29,7 @@ extern "C" Box* createSet();
 
 class BoxedSet : public Box {
 public:
-    typedef std::unordered_set<Box*, PyHasher, PyEq, StlCompatAllocator<Box*>> Set;
+    typedef llvm::DenseSet<BoxAndHash, BoxAndHash::Comparisons> Set;
     Set s;
     Box** weakreflist; /* List of weak references */
 

src/runtime/types.h

@@ -659,19 +659,16 @@ struct PyLt {
     bool operator()(Box*, Box*) const;
 };
 
-class BoxedDict : public Box {
-public:
-    // llvm::DenseMap doesn't store the original hash values, choosing to instead
-    // check for equality more often.  This is probably a good tradeoff when the keys
-    // are pointers and comparison is cheap, but we want to make sure that keys with
-    // different hash values don't get compared.
-    struct BoxAndHash {
+// llvm::DenseMap doesn't store the original hash values, choosing to instead
+// check for equality more often.  This is probably a good tradeoff when the keys
+// are pointers and comparison is cheap, but we want to make sure that keys with
+// different hash values don't get compared.
+struct BoxAndHash {
     Box* value;
     size_t hash;
 
     BoxAndHash(Box* value) : value(value), hash(PyHasher()(value)) {}
     BoxAndHash(Box* value, size_t hash) : value(value), hash(hash) {}
-    };
 
     struct Comparisons {
         static bool isEqual(BoxAndHash lhs, BoxAndHash rhs) {
@@ -687,8 +684,11 @@ public:
         static BoxAndHash getTombstoneKey() { return BoxAndHash((Box*)-2, 0); }
         static unsigned getHashValue(BoxAndHash val) { return val.hash; }
     };
+};
 
-    typedef llvm::DenseMap<BoxAndHash, Box*, Comparisons> DictMap;
+class BoxedDict : public Box {
+public:
+    typedef llvm::DenseMap<BoxAndHash, Box*, BoxAndHash::Comparisons> DictMap;
 
     DictMap d;