[interpreter] VisitForTest for bytecode generator

Adds TestResultScope and uses it to directly jump/fall through to the
correct branch in expressions used as branch conditions.
Should enable nicer TurboFan-graphs for easier control-flow
transformations in the future.

BUG=v8:4280
LOG=n

Review-Url: https://codereview.chromium.org/2242463002
Cr-Commit-Position: refs/heads/master@{#38634}

BUILD.gn

@@ -1381,6 +1381,7 @@ v8_source_set("v8_base") {
     "src/interpreter/bytecode-flags.h",
     "src/interpreter/bytecode-generator.cc",
     "src/interpreter/bytecode-generator.h",
+    "src/interpreter/bytecode-label.cc",
     "src/interpreter/bytecode-label.h",
     "src/interpreter/bytecode-peephole-optimizer.cc",
     "src/interpreter/bytecode-peephole-optimizer.h",

src/interpreter/bytecode-generator.h

@@ -48,6 +48,9 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   class GlobalDeclarationsBuilder;
   class RegisterResultScope;
   class RegisterAllocationScope;
+  class TestResultScope;
+
+  enum class TestFallthrough { kThen, kElse, kNone };
 
   void GenerateBytecode();
   void GenerateBytecodeBody();
@@ -162,6 +165,8 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
   MUST_USE_RESULT Register VisitForRegisterValue(Expression* expr);
   void VisitForRegisterValue(Expression* expr, Register destination);
   void VisitForEffect(Expression* expr);
+  void VisitForTest(Expression* expr, BytecodeLabels* then_labels,
+                    BytecodeLabels* else_labels, TestFallthrough fallthrough);
 
   // Methods for tracking and remapping register.
   void RecordStoreToRegister(Register reg);

src/interpreter/bytecode-label.cc

+// Copyright 2016 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/interpreter/bytecode-label.h"
+
+#include "src/interpreter/bytecode-array-builder.h"
+
+namespace v8 {
+namespace internal {
+namespace interpreter {
+
+BytecodeLabel* BytecodeLabels::New() {
+  labels_.push_back(BytecodeLabel());
+  return &labels_.back();
+}
+
+void BytecodeLabels::Bind(BytecodeArrayBuilder* builder) {
+  for (auto label : labels_) {
+    builder->Bind(&label);
+  }
+}
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8

src/interpreter/bytecode-label.h

@@ -5,10 +5,14 @@
 #ifndef V8_INTERPRETER_BYTECODE_LABEL_H_
 #define V8_INTERPRETER_BYTECODE_LABEL_H_
 
+#include "src/zone-containers.h"
+
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
+class BytecodeArrayBuilder;
+
 // A label representing a branch target in a bytecode array. When a
 // label is bound, it represents a known position in the bytecode
 // array. For labels that are forward references there can be at most
@@ -49,6 +53,21 @@ class BytecodeLabel final {
   friend class BytecodeArrayWriter;
 };
 
+// Class representing a branch target of multiple jumps.
+class BytecodeLabels {
+ public:
+  explicit BytecodeLabels(Zone* zone) : labels_(zone) {}
+
+  BytecodeLabel* New();
+
+  void Bind(BytecodeArrayBuilder* builder);
+
+ private:
+  ZoneVector<BytecodeLabel> labels_;
+
+  DISALLOW_COPY_AND_ASSIGN(BytecodeLabels);
+};
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8

src/v8.gyp

@@ -985,6 +985,7 @@
         'interpreter/bytecode-flags.h',
         'interpreter/bytecode-generator.cc',
         'interpreter/bytecode-generator.h',
+        'interpreter/bytecode-label.cc',
         'interpreter/bytecode-label.h',
         'interpreter/bytecode-peephole-optimizer.cc',
         'interpreter/bytecode-peephole-optimizer.h',

test/cctest/interpreter/bytecode_expectations/BasicBlockToBoolean.golden

@@ -18,10 +18,10 @@ bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
                 B(Star), R(0),
-  /*   45 S> */ B(JumpIfToBooleanTrue), U8(5),
+  /*   45 S> */ B(JumpIfToBooleanTrue), U8(7),
                 B(LdaZero),
   /*   56 E> */ B(TestLessThan), R(0),
-                B(JumpIfToBooleanFalse), U8(5),
+                B(JumpIfFalse), U8(5),
   /*   63 S> */ B(LdaSmi), U8(1),
   /*   75 S> */ B(Return),
                 B(LdaUndefined),
@@ -43,10 +43,10 @@ bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
                 B(Star), R(0),
-  /*   45 S> */ B(JumpIfToBooleanFalse), U8(5),
+  /*   45 S> */ B(JumpIfToBooleanFalse), U8(10),
                 B(LdaZero),
   /*   56 E> */ B(TestLessThan), R(0),
-                B(JumpIfToBooleanFalse), U8(5),
+                B(JumpIfFalse), U8(5),
   /*   63 S> */ B(LdaSmi), U8(1),
   /*   75 S> */ B(Return),
                 B(LdaUndefined),
@@ -68,10 +68,10 @@ bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaSmi), U8(1),
                 B(Star), R(0),
-  /*   45 S> */ B(JumpIfToBooleanTrue), U8(5),
+  /*   45 S> */ B(JumpIfToBooleanTrue), U8(7),
                 B(LdaZero),
   /*   57 E> */ B(TestLessThan), R(0),
-                B(JumpIfToBooleanFalse), U8(6),
+                B(JumpIfFalse), U8(6),
                 B(LdaSmi), U8(2),
                 B(Jump), U8(4),
                 B(LdaSmi), U8(3),

test/cctest/interpreter/bytecode_expectations/Conditional.golden

@@ -13,14 +13,10 @@ snippet: "
 "
 frame size: 0
 parameter count: 1
-bytecode array length: 12
+bytecode array length: 4
 bytecodes: [
   /*   30 E> */ B(StackCheck),
-  /*   34 S> */ B(LdaSmi), U8(1),
-                B(JumpIfToBooleanFalse), U8(6),
-                B(LdaSmi), U8(2),
-                B(Jump), U8(4),
-                B(LdaSmi), U8(3),
+  /*   34 S> */ B(LdaSmi), U8(2),
   /*   52 S> */ B(Return),
 ]
 constant pool: [
@@ -34,19 +30,58 @@ snippet: "
 "
 frame size: 0
 parameter count: 1
-bytecode array length: 20
+bytecode array length: 4
 bytecodes: [
   /*   30 E> */ B(StackCheck),
-  /*   34 S> */ B(LdaSmi), U8(1),
-                B(JumpIfToBooleanFalse), U8(14),
+  /*   34 S> */ B(LdaSmi), U8(3),
+  /*   60 S> */ B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+
+---
+snippet: "
+  return 0 < 1 ? 2 : 3;
+"
+frame size: 1
+parameter count: 1
+bytecode array length: 17
+bytecodes: [
+  /*   30 E> */ B(StackCheck),
+  /*   34 S> */ B(LdaZero),
+                B(Star), R(0),
+                B(LdaSmi), U8(1),
+  /*   43 E> */ B(TestLessThan), R(0),
+                B(JumpIfFalse), U8(6),
                 B(LdaSmi), U8(2),
-                B(JumpIfToBooleanFalse), U8(6),
-                B(LdaSmi), U8(3),
                 B(Jump), U8(4),
-                B(LdaSmi), U8(4),
+                B(LdaSmi), U8(3),
+  /*   56 S> */ B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+
+---
+snippet: "
+  var x = 0;
+  return x ? 2 : 3;
+"
+frame size: 1
+parameter count: 1
+bytecode array length: 13
+bytecodes: [
+  /*   30 E> */ B(StackCheck),
+  /*   42 S> */ B(LdaZero),
+                B(Star), R(0),
+  /*   45 S> */ B(JumpIfToBooleanFalse), U8(6),
+                B(LdaSmi), U8(2),
                 B(Jump), U8(4),
-                B(LdaSmi), U8(5),
-  /*   60 S> */ B(Return),
+                B(LdaSmi), U8(3),
+  /*   63 S> */ B(Return),
 ]
 constant pool: [
 ]

test/cctest/interpreter/bytecode_expectations/ForOf.golden

@@ -13,7 +13,7 @@ snippet: "
 "
 frame size: 16
 parameter count: 1
-bytecode array length: 283
+bytecode array length: 282
 bytecodes: [
   /*   30 E> */ B(StackCheck),
                 B(LdaZero),
@@ -70,11 +70,10 @@ bytecodes: [
                 B(Star), R(11),
                 B(LdaZero),
                 B(TestEqualStrict), R(3),
-                B(JumpIfTrue), U8(5),
+                B(JumpIfTrue), U8(123),
                 B(LdaUndefined),
                 B(TestEqualStrict), R(1),
-                B(ToBooleanLogicalNot),
-                B(JumpIfFalse), U8(118),
+                B(JumpIfTrue), U8(118),
                 B(LdrNamedProperty), R(1), U8(6), U8(13), R(5),
                 B(LdaNull),
                 B(TestEqual), R(5),
@@ -144,7 +143,7 @@ constant pool: [
 handlers: [
   [7, 121, 127],
   [10, 80, 82],
-  [200, 210, 212],
+  [199, 209, 211],
 ]
 
 ---
@@ -154,7 +153,7 @@ snippet: "
 "
 frame size: 17
 parameter count: 1
-bytecode array length: 296
+bytecode array length: 295
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(LdaConstant), U8(0),
@@ -213,11 +212,10 @@ bytecodes: [
                 B(Star), R(12),
                 B(LdaZero),
                 B(TestEqualStrict), R(3),
-                B(JumpIfTrue), U8(5),
+                B(JumpIfTrue), U8(123),
                 B(LdaUndefined),
                 B(TestEqualStrict), R(1),
-                B(ToBooleanLogicalNot),
-                B(JumpIfFalse), U8(118),
+                B(JumpIfTrue), U8(118),
                 B(LdrNamedProperty), R(1), U8(6), U8(13), R(5),
                 B(LdaNull),
                 B(TestEqual), R(5),
@@ -292,7 +290,7 @@ constant pool: [
 handlers: [
   [11, 124, 130],
   [14, 83, 85],
-  [204, 214, 216],
+  [203, 213, 215],
 ]
 
 ---
@@ -304,7 +302,7 @@ snippet: "
 "
 frame size: 16
 parameter count: 1
-bytecode array length: 299
+bytecode array length: 298
 bytecodes: [
   /*   30 E> */ B(StackCheck),
                 B(LdaZero),
@@ -369,11 +367,10 @@ bytecodes: [
                 B(Star), R(11),
                 B(LdaZero),
                 B(TestEqualStrict), R(3),
-                B(JumpIfTrue), U8(5),
+                B(JumpIfTrue), U8(123),
                 B(LdaUndefined),
                 B(TestEqualStrict), R(1),
-                B(ToBooleanLogicalNot),
-                B(JumpIfFalse), U8(118),
+                B(JumpIfTrue), U8(118),
                 B(LdrNamedProperty), R(1), U8(6), U8(13), R(5),
                 B(LdaNull),
                 B(TestEqual), R(5),
@@ -443,7 +440,7 @@ constant pool: [
 handlers: [
   [7, 137, 143],
   [10, 96, 98],
-  [216, 226, 228],
+  [215, 225, 227],
 ]
 
 ---
@@ -453,7 +450,7 @@ snippet: "
 "
 frame size: 15
 parameter count: 1
-bytecode array length: 309
+bytecode array length: 308
 bytecodes: [
   /*   30 E> */ B(StackCheck),
   /*   42 S> */ B(CreateObjectLiteral), U8(0), U8(0), U8(1), R(8),
@@ -515,11 +512,10 @@ bytecodes: [
                 B(Star), R(10),
                 B(LdaZero),
                 B(TestEqualStrict), R(2),
-                B(JumpIfTrue), U8(5),
+                B(JumpIfTrue), U8(123),
                 B(LdaUndefined),
                 B(TestEqualStrict), R(0),
-                B(ToBooleanLogicalNot),
-                B(JumpIfFalse), U8(118),
+                B(JumpIfTrue), U8(118),
                 B(LdrNamedProperty), R(0), U8(8), U8(17), R(4),
                 B(LdaNull),
                 B(TestEqual), R(4),
@@ -596,6 +592,6 @@ constant pool: [
 handlers: [
   [15, 137, 143],
   [18, 96, 98],
-  [217, 227, 229],
+  [216, 226, 228],
 ]
 

test/cctest/interpreter/bytecode_expectations/Generators.golden

@@ -264,7 +264,7 @@ snippet: "
 "
 frame size: 18
 parameter count: 1
-bytecode array length: 769
+bytecode array length: 768
 bytecodes: [
                 B(Ldar), R(new_target),
                 B(JumpIfUndefined), U8(26),
@@ -316,7 +316,7 @@ bytecodes: [
                 B(Star), R(6),
                 B(LdaZero),
                 B(Star), R(5),
-                B(JumpConstant), U8(16),
+                B(JumpConstant), U8(17),
                 B(Ldar), R(10),
   /*   11 E> */ B(Throw),
                 B(LdaConstant), U8(0),
@@ -452,12 +452,11 @@ bytecodes: [
                 B(LdrContextSlot), R(1), U8(9), R(11),
                 B(LdaZero),
                 B(TestEqualStrict), R(11),
-                B(JumpIfTrue), U8(9),
+                B(JumpIfTrueConstant), U8(15),
                 B(LdrContextSlot), R(1), U8(7), R(11),
                 B(LdaUndefined),
                 B(TestEqualStrict), R(11),
-                B(ToBooleanLogicalNot),
-                B(JumpIfFalseConstant), U8(15),
+                B(JumpIfTrueConstant), U8(16),
                 B(LdrContextSlot), R(1), U8(7), R(11),
                 B(LdaNamedProperty), R(11), U8(12), U8(13),
                 B(StaContextSlot), R(1), U8(11),
@@ -596,11 +595,12 @@ constant pool: [
   InstanceType::ONE_BYTE_INTERNALIZED_STRING_TYPE,
   kInstanceTypeDontCare,
   kInstanceTypeDontCare,
+  kInstanceTypeDontCare,
 ]
 handlers: [
-  [41, 688, 694],
+  [41, 687, 693],
   [147, 442, 448],
   [150, 396, 398],
-  [545, 557, 559],
+  [544, 556, 558],
 ]
 

test/cctest/interpreter/bytecode_expectations/IfConditions.golden

@@ -737,3 +737,47 @@ constant pool: [
 handlers: [
 ]
 
+---
+snippet: "
+  function f(a, b) {
+    if (a == b || a < 0) {
+      return 1;
+    } else if (a > 0 && b > 0) {
+      return 0;
+    } else {
+      return -1;
+    }
+  };
+  f(-1, 1);
+"
+frame size: 0
+parameter count: 3
+bytecode array length: 32
+bytecodes: [
+  /*   10 E> */ B(StackCheck),
+  /*   21 S> */ B(Ldar), R(arg1),
+  /*   27 E> */ B(TestEqual), R(arg0),
+                B(JumpIfTrue), U8(7),
+                B(LdaZero),
+  /*   37 E> */ B(TestLessThan), R(arg0),
+                B(JumpIfFalse), U8(5),
+  /*   48 S> */ B(LdaSmi), U8(1),
+  /*  133 S> */ B(Return),
+  /*   67 S> */ B(LdaZero),
+  /*   73 E> */ B(TestGreaterThan), R(arg0),
+                B(JumpIfFalse), U8(9),
+                B(LdaZero),
+  /*   82 E> */ B(TestGreaterThan), R(arg1),
+                B(JumpIfFalse), U8(4),
+  /*   93 S> */ B(LdaZero),
+  /*  133 S> */ B(Return),
+  /*  118 S> */ B(LdaSmi), U8(-1),
+  /*  133 S> */ B(Return),
+                B(LdaUndefined),
+  /*  133 S> */ B(Return),
+]
+constant pool: [
+]
+handlers: [
+]
+

test/cctest/interpreter/test-bytecode-generator.cc

@@ -705,6 +705,17 @@ TEST(IfConditions) {
     "  }\n"
     "};\n"
     "f();\n",
+
+    "function f(a, b) {\n"
+    "  if (a == b || a < 0) {\n"
+    "    return 1;\n"
+    "  } else if (a > 0 && b > 0) {\n"
+    "    return 0;\n"
+    "  } else {\n"
+    "    return -1;\n"
+    "  }\n"
+    "};\n"
+    "f(-1, 1);\n",
   };
 
   CHECK(CompareTexts(BuildActual(printer, snippets),
@@ -1615,6 +1626,11 @@ TEST(Conditional) {
       "return 1 ? 2 : 3;\n",
 
       "return 1 ? 2 ? 3 : 4 : 5;\n",
+
+      "return 0 < 1 ? 2 : 3;\n",
+
+      "var x = 0;\n"
+      "return x ? 2 : 3;\n",
   };
 
   CHECK(CompareTexts(BuildActual(printer, snippets),

test/cctest/test-func-name-inference.cc

@@ -287,7 +287,8 @@ TEST(MultipleFuncsConditional) {
   v8::HandleScope scope(CcTest::isolate());
 
   v8::Local<v8::Script> script = Compile(CcTest::isolate(),
-                                         "fun1 = 0 ?\n"
+                                         "var x = 0;\n"
+                                         "fun1 = x ?\n"
                                          "    function() { return 1; } :\n"
                                          "    function() { return 2; }");
   CheckFunctionName(script, "return 1", "fun1");
@@ -301,9 +302,10 @@ TEST(MultipleFuncsInLiteral) {
 
   v8::Local<v8::Script> script =
       Compile(CcTest::isolate(),
+              "var x = 0;\n"
               "function MyClass() {}\n"
               "MyClass.prototype = {\n"
-              "  method1: 0 ? function() { return 1; } :\n"
+              "  method1: x ? function() { return 1; } :\n"
               "               function() { return 2; } }");
   CheckFunctionName(script, "return 1", "MyClass.method1");
   CheckFunctionName(script, "return 2", "MyClass.method1");