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test/cctest/compiler/compiler/test-js-context-specialization.cc

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/compiler/js-context-specialization.h"
+#include "src/compiler/js-operator.h"
+#include "src/compiler/node-matchers.h"
+#include "src/compiler/node-properties-inl.h"
+#include "src/compiler/simplified-node-factory.h"
+#include "src/compiler/source-position.h"
+#include "src/compiler/typer.h"
+#include "test/cctest/cctest.h"
+#include "test/cctest/compiler/function-tester.h"
+#include "test/cctest/compiler/graph-builder-tester.h"
+
+using namespace v8::internal;
+using namespace v8::internal::compiler;
+
+class ContextSpecializationTester
+    : public HandleAndZoneScope,
+      public DirectGraphBuilder,
+      public SimplifiedNodeFactory<ContextSpecializationTester> {
+ public:
+  ContextSpecializationTester()
+      : DirectGraphBuilder(new (main_zone()) Graph(main_zone())),
+        common_(main_zone()),
+        javascript_(main_zone()),
+        simplified_(main_zone()),
+        typer_(main_zone()),
+        jsgraph_(graph(), common(), &typer_),
+        info_(main_isolate(), main_zone()) {}
+
+  Factory* factory() { return main_isolate()->factory(); }
+  CommonOperatorBuilder* common() { return &common_; }
+  JSOperatorBuilder* javascript() { return &javascript_; }
+  SimplifiedOperatorBuilder* simplified() { return &simplified_; }
+  JSGraph* jsgraph() { return &jsgraph_; }
+  CompilationInfo* info() { return &info_; }
+
+ private:
+  CommonOperatorBuilder common_;
+  JSOperatorBuilder javascript_;
+  SimplifiedOperatorBuilder simplified_;
+  Typer typer_;
+  JSGraph jsgraph_;
+  CompilationInfo info_;
+};
+
+
+TEST(ReduceJSLoadContext) {
+  ContextSpecializationTester t;
+
+  Node* start = t.NewNode(t.common()->Start());
+  t.graph()->SetStart(start);
+
+  // Make a context and initialize it a bit for this test.
+  Handle<Context> native = t.factory()->NewNativeContext();
+  Handle<Context> ctx1 = t.factory()->NewNativeContext();
+  Handle<Context> ctx2 = t.factory()->NewNativeContext();
+  ctx2->set_previous(*ctx1);
+  ctx1->set_previous(*native);
+  Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
+  const int slot = Context::GLOBAL_OBJECT_INDEX;
+  native->set(slot, *expected);
+
+  Node* const_context = t.jsgraph()->Constant(native);
+  Node* param_context = t.NewNode(t.common()->Parameter(0));
+  JSContextSpecializer spec(t.info(), t.jsgraph(), const_context);
+
+  {
+    // Mutable slot, constant context, depth = 0 => do nothing.
+    t.info()->SetContext(native);
+    Node* load = t.NewNode(t.javascript()->LoadContext(0, 0, false),
+                           const_context, start, start);
+    Reduction r = spec.ReduceJSLoadContext(load);
+    CHECK(!r.Changed());
+  }
+
+  {
+    // Mutable slot, non-constant context, depth = 0 => do nothing.
+    t.info()->SetContext(native);
+    Node* load = t.NewNode(t.javascript()->LoadContext(0, 0, false),
+                           param_context, start, start);
+    Reduction r = spec.ReduceJSLoadContext(load);
+    CHECK(!r.Changed());
+  }
+
+  {
+    // Mutable slot, non-constant context, depth > 0 => fold-in parent context.
+    t.info()->SetContext(ctx2);
+    Node* load = t.NewNode(
+        t.javascript()->LoadContext(2, Context::GLOBAL_EVAL_FUN_INDEX, false),
+        param_context, start, start);
+    Reduction r = spec.ReduceJSLoadContext(load);
+    CHECK(r.Changed());
+    CHECK_EQ(IrOpcode::kHeapConstant, r.replacement()->InputAt(0)->opcode());
+    ValueMatcher<Handle<Context> > match(r.replacement()->InputAt(0));
+    CHECK_EQ(*native, *match.Value());
+    ContextAccess access = static_cast<Operator1<ContextAccess>*>(
+                               r.replacement()->op())->parameter();
+    CHECK_EQ(Context::GLOBAL_EVAL_FUN_INDEX, access.index());
+    CHECK_EQ(0, access.depth());
+    CHECK_EQ(false, access.immutable());
+  }
+
+  {
+    // Immutable slot, constant context => specialize.
+    t.info()->SetContext(native);
+    Node* load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
+                           const_context, start, start);
+    Reduction r = spec.ReduceJSLoadContext(load);
+    CHECK(r.Changed());
+    CHECK(r.replacement() != load);
+
+    ValueMatcher<Handle<Object> > match(r.replacement());
+    CHECK(match.HasValue());
+    CHECK_EQ(*expected, *match.Value());
+  }
+
+  {
+    // Immutable slot, non-constant context => specialize.
+    t.info()->SetContext(native);
+    Node* load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
+                           param_context, start, start);
+    Reduction r = spec.ReduceJSLoadContext(load);
+    CHECK(r.Changed());
+    CHECK(r.replacement() != load);
+
+    ValueMatcher<Handle<Object> > match(r.replacement());
+    CHECK(match.HasValue());
+    CHECK_EQ(*expected, *match.Value());
+  }
+
+  // TODO(titzer): test with other kinds of contexts, e.g. a function context.
+  // TODO(sigurds): test that loads below create context are not optimized
+}
+
+
+// TODO(titzer): factor out common code with effects checking in typed lowering.
+static void CheckEffectInput(Node* effect, Node* use) {
+  CHECK_EQ(effect, NodeProperties::GetEffectInput(use));
+}
+
+
+TEST(SpecializeToContext) {
+  ContextSpecializationTester t;
+
+  Node* start = t.NewNode(t.common()->Start());
+  t.graph()->SetStart(start);
+
+  // Make a context and initialize it a bit for this test.
+  Handle<Context> native = t.factory()->NewNativeContext();
+  Handle<Object> expected = t.factory()->InternalizeUtf8String("gboy!");
+  const int slot = Context::GLOBAL_OBJECT_INDEX;
+  native->set(slot, *expected);
+  t.info()->SetContext(native);
+
+  Node* const_context = t.jsgraph()->Constant(native);
+  Node* param_context = t.NewNode(t.common()->Parameter(0));
+  JSContextSpecializer spec(t.info(), t.jsgraph(), const_context);
+
+  {
+    // Check that SpecializeToContext() replaces values and forwards effects
+    // correctly, and folds values from constant and non-constant contexts
+    Node* effect_in = t.NewNode(t.common()->Start());
+    Node* load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
+                           const_context, const_context, effect_in, start);
+
+
+    Node* value_use = t.ChangeTaggedToInt32(load);
+    Node* other_load = t.NewNode(t.javascript()->LoadContext(0, slot, true),
+                                 param_context, param_context, load, start);
+    Node* effect_use = other_load;
+    Node* other_use = t.ChangeTaggedToInt32(other_load);
+
+    // Double check the above graph is what we expect, or the test is broken.
+    CheckEffectInput(effect_in, load);
+    CheckEffectInput(load, effect_use);
+
+    // Perform the substitution on the entire graph.
+    spec.SpecializeToContext();
+
+    // Effects should have been forwarded (not replaced with a value).
+    CheckEffectInput(effect_in, effect_use);
+
+    // Use of {other_load} should not have been replaced.
+    CHECK_EQ(other_load, other_use->InputAt(0));
+
+    Node* replacement = value_use->InputAt(0);
+    ValueMatcher<Handle<Object> > match(replacement);
+    CHECK(match.HasValue());
+    CHECK_EQ(*expected, *match.Value());
+  }
+  // TODO(titzer): clean up above test and test more complicated effects.
+}
+
+
+TEST(SpecializeJSFunction_ToConstant1) {
+  FunctionTester T(
+      "(function() { var x = 1; function inc(a)"
+      " { return a + x; } return inc; })()");
+
+  T.CheckCall(1.0, 0.0, 0.0);
+  T.CheckCall(2.0, 1.0, 0.0);
+  T.CheckCall(2.1, 1.1, 0.0);
+}
+
+
+TEST(SpecializeJSFunction_ToConstant2) {
+  FunctionTester T(
+      "(function() { var x = 1.5; var y = 2.25; var z = 3.75;"
+      " function f(a) { return a - x + y - z; } return f; })()");
+
+  T.CheckCall(-3.0, 0.0, 0.0);
+  T.CheckCall(-2.0, 1.0, 0.0);
+  T.CheckCall(-1.9, 1.1, 0.0);
+}
+
+
+TEST(SpecializeJSFunction_ToConstant3) {
+  FunctionTester T(
+      "(function() { var x = -11.5; function inc()"
+      " { return (function(a) { return a + x; }); }"
+      " return inc(); })()");
+
+  T.CheckCall(-11.5, 0.0, 0.0);
+  T.CheckCall(-10.5, 1.0, 0.0);
+  T.CheckCall(-10.4, 1.1, 0.0);
+}
+
+
+TEST(SpecializeJSFunction_ToConstant_uninit) {
+  {
+    FunctionTester T(
+        "(function() { if (false) { var x = 1; } function inc(a)"
+        " { return x; } return inc; })()");  // x is undefined!
+
+    CHECK(T.Call(T.Val(0.0), T.Val(0.0)).ToHandleChecked()->IsUndefined());
+    CHECK(T.Call(T.Val(2.0), T.Val(0.0)).ToHandleChecked()->IsUndefined());
+    CHECK(T.Call(T.Val(-2.1), T.Val(0.0)).ToHandleChecked()->IsUndefined());
+  }
+
+  {
+    FunctionTester T(
+        "(function() { if (false) { var x = 1; } function inc(a)"
+        " { return a + x; } return inc; })()");  // x is undefined!
+
+    CHECK(T.Call(T.Val(0.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
+    CHECK(T.Call(T.Val(2.0), T.Val(0.0)).ToHandleChecked()->IsNaN());
+    CHECK(T.Call(T.Val(-2.1), T.Val(0.0)).ToHandleChecked()->IsNaN());
+  }
+}