Merge branch 'generator-simple-destructor' of https://github.com/toshok/pyston

Conflicts:
	src/runtime/generator.cpp

Closes #307

minibenchmarks/bm_ai.py

+#!/usr/bin/env python
+
+"""Wrapper script for testing the performance of simple AI systems.
+
+bm_ai.py runs the following little solvers:
+    - N-Queens
+
+This used to contain an alphametics solver, but that was found to be bound
+primarily by eval() performance.
+"""
+
+# Wanted by the alphametics solver.
+from __future__ import division
+
+__author__ = "collinwinter@google.com (Collin Winter)"
+
+# Python imports
+import optparse
+import re
+import string
+import time
+
+# Pure-Python implementation of itertools.permutations().
+def permutations(iterable, r=None):
+    """permutations(range(3), 2) --> (0,1) (0,2) (1,0) (1,2) (2,0) (2,1)"""
+    pool = tuple(iterable)
+    n = len(pool)
+    if r is None:
+        r = n
+    indices = range(n)
+    cycles = range(n-r+1, n+1)[::-1]
+    yield tuple(pool[i] for i in indices[:r])
+    while n:
+        for i in reversed(range(r)):
+            cycles[i] -= 1
+            if cycles[i] == 0:
+                indices[i:] = indices[i+1:] + indices[i:i+1]
+                cycles[i] = n - i
+            else:
+                j = cycles[i]
+                indices[i], indices[-j] = indices[-j], indices[i]
+                yield tuple(pool[i] for i in indices[:r])
+                break
+        else:
+            return
+
+
+# From http://code.activestate.com/recipes/576647/
+def n_queens(queen_count):
+    """N-Queens solver.
+
+    Args:
+        queen_count: the number of queens to solve for. This is also the
+            board size.
+
+    Yields:
+        Solutions to the problem. Each yielded value is looks like
+        (3, 8, 2, 1, 4, ..., 6) where each number is the column position for the
+        queen, and the index into the tuple indicates the row.
+    """
+    cols = range(queen_count)
+    for vec in permutations(cols):
+        if (queen_count == len(set(vec[i]+i for i in cols))
+                        == len(set(vec[i]-i for i in cols))):
+            yield vec
+
+
+def test_n_queens(iterations):
+    # Warm-up runs.
+    list(n_queens(8))
+    list(n_queens(8))
+
+    times = []
+    for _ in xrange(iterations):
+        t0 = time.time()
+        list(n_queens(8))
+        t1 = time.time()
+        times.append(t1 - t0)
+    return times
+
+
+test_n_queens(1)

src/runtime/generator.cpp

@@ -184,35 +184,47 @@ extern "C" BoxedGenerator::BoxedGenerator(BoxedFunctionBase* function, Box* arg1
         memcpy(&this->args->elts[0], args, numArgs * sizeof(Box*));
     }
 
-    uint64_t stack_low = next_stack_addr;
-    uint64_t stack_high = stack_low + MAX_STACK_SIZE;
-    next_stack_addr = stack_high;
+    void* initial_stack_limit;
+    if (available_addrs.size() == 0) {
+        uint64_t stack_low = next_stack_addr;
+        uint64_t stack_high = stack_low + MAX_STACK_SIZE;
+        next_stack_addr = stack_high;
 
 #if STACK_GROWS_DOWN
-    this->stack_begin = (void*)stack_high;
-
-    void* initial_stack_limit = (void*)(stack_high - INITIAL_STACK_SIZE);
-    void* p = mmap(initial_stack_limit, INITIAL_STACK_SIZE, PROT_READ | PROT_WRITE,
-                   MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS | MAP_GROWSDOWN, -1, 0);
-    ASSERT(p == initial_stack_limit, "%p %s", p, strerror(errno));
-
-    // Create an inaccessible redzone so that the generator stack won't grow indefinitely.
-    // Looks like it throws a SIGBUS if we reach the redzone; it's unclear if that's better
-    // or worse than being able to consume all available memory.
-    void* p2 = mmap((void*)stack_low, STACK_REDZONE_SIZE, PROT_NONE, MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
-    assert(p2 == (void*)stack_low);
-    // Interestingly, it seems like MAP_GROWSDOWN will leave a page-size gap between the redzone and the growable
-    // region.
-
-    if (VERBOSITY() >= 1) {
-        printf("Created new generator stack, starts at %p, currently extends to %p\n", (void*)stack_high,
-               initial_stack_limit);
-        printf("Created a redzone from %p-%p\n", (void*)stack_low, (void*)(stack_low + STACK_REDZONE_SIZE));
-    }
-
+        this->stack_begin = (void*)stack_high;
+
+        initial_stack_limit = (void*)(stack_high - INITIAL_STACK_SIZE);
+        void* p = mmap(initial_stack_limit, INITIAL_STACK_SIZE, PROT_READ | PROT_WRITE,
+                       MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS | MAP_GROWSDOWN, -1, 0);
+        ASSERT(p == initial_stack_limit, "%p %s", p, strerror(errno));
+
+        // Create an inaccessible redzone so that the generator stack won't grow indefinitely.
+        // Looks like it throws a SIGBUS if we reach the redzone; it's unclear if that's better
+        // or worse than being able to consume all available memory.
+        void* p2
+            = mmap((void*)stack_low, STACK_REDZONE_SIZE, PROT_NONE, MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
+        assert(p2 == (void*)stack_low);
+        // Interestingly, it seems like MAP_GROWSDOWN will leave a page-size gap between the redzone and the growable
+        // region.
+
+        if (VERBOSITY() >= 1) {
+            printf("Created new generator stack, starts at %p, currently extends to %p\n", (void*)stack_high,
+                   initial_stack_limit);
+            printf("Created a redzone from %p-%p\n", (void*)stack_low, (void*)(stack_low + STACK_REDZONE_SIZE));
+        }
+#else
+#error "implement me"
+#endif
+    } else {
+#if STACK_GROWS_DOWN
+        uint64_t stack_high = available_addrs.back();
+        this->stack_begin = (void*)stack_high;
+        initial_stack_limit = (void*)(stack_high - INITIAL_STACK_SIZE);
+        available_addrs.pop_back();
 #else
 #error "implement me"
 #endif
+    }
 
     assert(((intptr_t)stack_begin & (~(intptr_t)(0xF))) == (intptr_t)stack_begin && "stack must be aligned");
 
@@ -254,10 +266,19 @@ extern "C" void generatorGCHandler(GCVisitor* v, Box* b) {
     }
 }
 
+void generatorDestructor(Box* b) {
+    assert(isSubclass(b->cls, generator_cls));
+    BoxedGenerator* self = static_cast<BoxedGenerator*>(b);
+
+    if (self->stack_begin)
+        available_addrs.push_back((uint64_t)self->stack_begin);
+    self->stack_begin = NULL;
+}
 
 void setupGenerator() {
     generator_cls = new BoxedHeapClass(object_cls, &generatorGCHandler, offsetof(BoxedGenerator, attrs),
                                        sizeof(BoxedGenerator), false, "generator");
+    generator_cls->simple_destructor = generatorDestructor;
     generator_cls->giveAttr("__iter__",
                             new BoxedFunction(boxRTFunction((void*)generatorIter, typeFromClass(generator_cls), 1)));