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      1 // Copyright 2014 the V8 project authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "src/compiler/js-context-specialization.h"
      6 #include "src/compiler/js-graph.h"
      7 #include "src/compiler/js-operator.h"
      8 #include "src/compiler/node-matchers.h"
      9 #include "src/compiler/node-properties.h"
     10 #include "src/compiler/source-position.h"
     11 #include "test/cctest/cctest.h"
     12 #include "test/cctest/compiler/function-tester.h"
     13 #include "test/cctest/compiler/graph-builder-tester.h"
     14 
     15 namespace v8 {
     16 namespace internal {
     17 namespace compiler {
     18 
     19 class ContextSpecializationTester : public HandleAndZoneScope {
     20  public:
     21   ContextSpecializationTester()
     22       : graph_(new (main_zone()) Graph(main_zone())),
     23         common_(main_zone()),
     24         javascript_(main_zone()),
     25         machine_(main_zone()),
     26         simplified_(main_zone()),
     27         jsgraph_(main_isolate(), graph(), common(), &javascript_, &simplified_,
     28                  &machine_),
     29         reducer_(main_zone(), graph()),
     30         spec_(&reducer_, jsgraph(), MaybeHandle<Context>()) {}
     31 
     32   JSContextSpecialization* spec() { return &spec_; }
     33   Factory* factory() { return main_isolate()->factory(); }
     34   CommonOperatorBuilder* common() { return &common_; }
     35   JSOperatorBuilder* javascript() { return &javascript_; }
     36   SimplifiedOperatorBuilder* simplified() { return &simplified_; }
     37   JSGraph* jsgraph() { return &jsgraph_; }
     38   Graph* graph() { return graph_; }
     39 
     40  private:
     41   Graph* graph_;
     42   CommonOperatorBuilder common_;
     43   JSOperatorBuilder javascript_;
     44   MachineOperatorBuilder machine_;
     45   SimplifiedOperatorBuilder simplified_;
     46   JSGraph jsgraph_;
     47   GraphReducer reducer_;
     48   JSContextSpecialization spec_;
     49 };
     50 
     51 
     52 TEST(ReduceJSLoadContext) {
     53   ContextSpecializationTester t;
     54 
     55   Node* start = t.graph()->NewNode(t.common()->Start(0));
     56   t.graph()->SetStart(start);
     57 
     58   // Make a context and initialize it a bit for this test.
     59   Handle<Context> native = t.factory()->NewNativeContext();
     60   Handle<Context> subcontext1 = t.factory()->NewNativeContext();
     61   Handle<Context> subcontext2 = t.factory()->NewNativeContext();
     62   subcontext2->set_previous(*subcontext1);
     63   subcontext1->set_previous(*native);
     64   Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
     65   const int slot = Context::NATIVE_CONTEXT_INDEX;
     66   native->set(slot, *expected);
     67 
     68   Node* const_context = t.jsgraph()->Constant(native);
     69   Node* deep_const_context = t.jsgraph()->Constant(subcontext2);
     70   Node* param_context = t.graph()->NewNode(t.common()->Parameter(0), start);
     71 
     72   {
     73     // Mutable slot, constant context, depth = 0 => do nothing.
     74     Node* load = t.graph()->NewNode(t.javascript()->LoadContext(0, 0, false),
     75                                     const_context, const_context, start);
     76     Reduction r = t.spec()->Reduce(load);
     77     CHECK(!r.Changed());
     78   }
     79 
     80   {
     81     // Mutable slot, non-constant context, depth = 0 => do nothing.
     82     Node* load = t.graph()->NewNode(t.javascript()->LoadContext(0, 0, false),
     83                                     param_context, param_context, start);
     84     Reduction r = t.spec()->Reduce(load);
     85     CHECK(!r.Changed());
     86   }
     87 
     88   {
     89     // Mutable slot, constant context, depth > 0 => fold-in parent context.
     90     Node* load = t.graph()->NewNode(
     91         t.javascript()->LoadContext(2, Context::GLOBAL_EVAL_FUN_INDEX, false),
     92         deep_const_context, deep_const_context, start);
     93     Reduction r = t.spec()->Reduce(load);
     94     CHECK(r.Changed());
     95     Node* new_context_input = NodeProperties::GetValueInput(r.replacement(), 0);
     96     CHECK_EQ(IrOpcode::kHeapConstant, new_context_input->opcode());
     97     HeapObjectMatcher match(new_context_input);
     98     CHECK_EQ(*native, *match.Value());
     99     ContextAccess access = OpParameter<ContextAccess>(r.replacement());
    100     CHECK_EQ(Context::GLOBAL_EVAL_FUN_INDEX, static_cast<int>(access.index()));
    101     CHECK_EQ(0, static_cast<int>(access.depth()));
    102     CHECK_EQ(false, access.immutable());
    103   }
    104 
    105   {
    106     // Immutable slot, constant context, depth = 0 => specialize.
    107     Node* load = t.graph()->NewNode(t.javascript()->LoadContext(0, slot, true),
    108                                     const_context, const_context, start);
    109     Reduction r = t.spec()->Reduce(load);
    110     CHECK(r.Changed());
    111     CHECK(r.replacement() != load);
    112 
    113     HeapObjectMatcher match(r.replacement());
    114     CHECK(match.HasValue());
    115     CHECK_EQ(*expected, *match.Value());
    116   }
    117 
    118   // TODO(titzer): test with other kinds of contexts, e.g. a function context.
    119   // TODO(sigurds): test that loads below create context are not optimized
    120 }
    121 
    122 
    123 TEST(ReduceJSStoreContext) {
    124   ContextSpecializationTester t;
    125 
    126   Node* start = t.graph()->NewNode(t.common()->Start(0));
    127   t.graph()->SetStart(start);
    128 
    129   // Make a context and initialize it a bit for this test.
    130   Handle<Context> native = t.factory()->NewNativeContext();
    131   Handle<Context> subcontext1 = t.factory()->NewNativeContext();
    132   Handle<Context> subcontext2 = t.factory()->NewNativeContext();
    133   subcontext2->set_previous(*subcontext1);
    134   subcontext1->set_previous(*native);
    135   Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
    136   const int slot = Context::NATIVE_CONTEXT_INDEX;
    137   native->set(slot, *expected);
    138 
    139   Node* const_context = t.jsgraph()->Constant(native);
    140   Node* deep_const_context = t.jsgraph()->Constant(subcontext2);
    141   Node* param_context = t.graph()->NewNode(t.common()->Parameter(0), start);
    142 
    143   {
    144     // Mutable slot, constant context, depth = 0 => do nothing.
    145     Node* load =
    146         t.graph()->NewNode(t.javascript()->StoreContext(0, 0), const_context,
    147                            const_context, const_context, start, start);
    148     Reduction r = t.spec()->Reduce(load);
    149     CHECK(!r.Changed());
    150   }
    151 
    152   {
    153     // Mutable slot, non-constant context, depth = 0 => do nothing.
    154     Node* load =
    155         t.graph()->NewNode(t.javascript()->StoreContext(0, 0), param_context,
    156                            param_context, const_context, start, start);
    157     Reduction r = t.spec()->Reduce(load);
    158     CHECK(!r.Changed());
    159   }
    160 
    161   {
    162     // Immutable slot, constant context, depth = 0 => do nothing.
    163     Node* load =
    164         t.graph()->NewNode(t.javascript()->StoreContext(0, slot), const_context,
    165                            const_context, const_context, start, start);
    166     Reduction r = t.spec()->Reduce(load);
    167     CHECK(!r.Changed());
    168   }
    169 
    170   {
    171     // Mutable slot, constant context, depth > 0 => fold-in parent context.
    172     Node* load = t.graph()->NewNode(
    173         t.javascript()->StoreContext(2, Context::GLOBAL_EVAL_FUN_INDEX),
    174         deep_const_context, deep_const_context, const_context, start, start);
    175     Reduction r = t.spec()->Reduce(load);
    176     CHECK(r.Changed());
    177     Node* new_context_input = NodeProperties::GetValueInput(r.replacement(), 0);
    178     CHECK_EQ(IrOpcode::kHeapConstant, new_context_input->opcode());
    179     HeapObjectMatcher match(new_context_input);
    180     CHECK_EQ(*native, *match.Value());
    181     ContextAccess access = OpParameter<ContextAccess>(r.replacement());
    182     CHECK_EQ(Context::GLOBAL_EVAL_FUN_INDEX, static_cast<int>(access.index()));
    183     CHECK_EQ(0, static_cast<int>(access.depth()));
    184     CHECK_EQ(false, access.immutable());
    185   }
    186 }
    187 
    188 
    189 // TODO(titzer): factor out common code with effects checking in typed lowering.
    190 static void CheckEffectInput(Node* effect, Node* use) {
    191   CHECK_EQ(effect, NodeProperties::GetEffectInput(use));
    192 }
    193 
    194 
    195 TEST(SpecializeToContext) {
    196   ContextSpecializationTester t;
    197 
    198   Node* start = t.graph()->NewNode(t.common()->Start(0));
    199   t.graph()->SetStart(start);
    200 
    201   // Make a context and initialize it a bit for this test.
    202   Handle<Context> native = t.factory()->NewNativeContext();
    203   Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
    204   const int slot = Context::NATIVE_CONTEXT_INDEX;
    205   native->set(slot, *expected);
    206 
    207   Node* const_context = t.jsgraph()->Constant(native);
    208   Node* param_context = t.graph()->NewNode(t.common()->Parameter(0), start);
    209 
    210   {
    211     // Check that specialization replaces values and forwards effects
    212     // correctly, and folds values from constant and non-constant contexts
    213     Node* effect_in = start;
    214     Node* load = t.graph()->NewNode(t.javascript()->LoadContext(0, slot, true),
    215                                     const_context, const_context, effect_in);
    216 
    217 
    218     Node* value_use =
    219         t.graph()->NewNode(t.simplified()->ChangeTaggedToInt32(), load);
    220     Node* other_load =
    221         t.graph()->NewNode(t.javascript()->LoadContext(0, slot, true),
    222                            param_context, param_context, load);
    223     Node* effect_use = other_load;
    224     Node* other_use =
    225         t.graph()->NewNode(t.simplified()->ChangeTaggedToInt32(), other_load);
    226 
    227     Node* add = t.graph()->NewNode(
    228         t.javascript()->Add(LanguageMode::SLOPPY, BinaryOperationHints::Any()),
    229         value_use, other_use, param_context, t.jsgraph()->EmptyFrameState(),
    230         t.jsgraph()->EmptyFrameState(), other_load, start);
    231 
    232     Node* ret =
    233         t.graph()->NewNode(t.common()->Return(), add, effect_use, start);
    234     Node* end = t.graph()->NewNode(t.common()->End(1), ret);
    235     USE(end);
    236     t.graph()->SetEnd(end);
    237 
    238     // Double check the above graph is what we expect, or the test is broken.
    239     CheckEffectInput(effect_in, load);
    240     CheckEffectInput(load, effect_use);
    241 
    242     // Perform the reduction on the entire graph.
    243     GraphReducer graph_reducer(t.main_zone(), t.graph());
    244     JSContextSpecialization spec(&graph_reducer, t.jsgraph(),
    245                                  MaybeHandle<Context>());
    246     graph_reducer.AddReducer(&spec);
    247     graph_reducer.ReduceGraph();
    248 
    249     // Effects should have been forwarded (not replaced with a value).
    250     CheckEffectInput(effect_in, effect_use);
    251 
    252     // Use of {other_load} should not have been replaced.
    253     CHECK_EQ(other_load, other_use->InputAt(0));
    254 
    255     Node* replacement = value_use->InputAt(0);
    256     HeapObjectMatcher match(replacement);
    257     CHECK(match.HasValue());
    258     CHECK_EQ(*expected, *match.Value());
    259   }
    260   // TODO(titzer): clean up above test and test more complicated effects.
    261 }
    262 
    263 
    264 TEST(SpecializeJSFunction_ToConstant1) {
    265   FunctionTester T(
    266       "(function() { var x = 1; function inc(a)"
    267       " { return a + x; } return inc; })()");
    268 
    269   T.CheckCall(1.0, 0.0, 0.0);
    270   T.CheckCall(2.0, 1.0, 0.0);
    271   T.CheckCall(2.1, 1.1, 0.0);
    272 }
    273 
    274 
    275 TEST(SpecializeJSFunction_ToConstant2) {
    276   FunctionTester T(
    277       "(function() { var x = 1.5; var y = 2.25; var z = 3.75;"
    278       " function f(a) { return a - x + y - z; } return f; })()");
    279 
    280   T.CheckCall(-3.0, 0.0, 0.0);
    281   T.CheckCall(-2.0, 1.0, 0.0);
    282   T.CheckCall(-1.9, 1.1, 0.0);
    283 }
    284 
    285 
    286 TEST(SpecializeJSFunction_ToConstant3) {
    287   FunctionTester T(
    288       "(function() { var x = -11.5; function inc()"
    289       " { return (function(a) { return a + x; }); }"
    290       " return inc(); })()");
    291 
    292   T.CheckCall(-11.5, 0.0, 0.0);
    293   T.CheckCall(-10.5, 1.0, 0.0);
    294   T.CheckCall(-10.4, 1.1, 0.0);
    295 }
    296 
    297 
    298 TEST(SpecializeJSFunction_ToConstant_uninit) {
    299   {
    300     FunctionTester T(
    301         "(function() { if (false) { var x = 1; } function inc(a)"
    302         " { return x; } return inc; })()");  // x is undefined!
    303 
    304     CHECK(T.Call(T.Val(0.0), T.Val(0.0)).ToHandleChecked()->IsUndefined());
    305     CHECK(T.Call(T.Val(2.0), T.Val(0.0)).ToHandleChecked()->IsUndefined());
    306     CHECK(T.Call(T.Val(-2.1), T.Val(0.0)).ToHandleChecked()->IsUndefined());
    307   }
    308 
    309   {
    310     FunctionTester T(
    311         "(function() { if (false) { var x = 1; } function inc(a)"
    312         " { return a + x; } return inc; })()");  // x is undefined!
    313 
    314     CHECK(T.Call(T.Val(0.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
    315     CHECK(T.Call(T.Val(2.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
    316     CHECK(T.Call(T.Val(-2.1), T.Val(0.0)).ToHandleChecked()->IsNaN());
    317   }
    318 }
    319 
    320 }  // namespace compiler
    321 }  // namespace internal
    322 }  // namespace v8
    323