[Interpreter] Ensure ToBoolean bytecodes are correctly emitted at the start of basic blocks

test/unittests/interpreter/bytecode-array-builder-unittest.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/v8.h"
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/interpreter/bytecode-array-iterator.h"
 #include "test/unittests/test-utils.h"
 
@@ skipping 167 matching lines @@
       .JumpIfTrue(&start)
       .CompareOperation(Token::Value::EQ, reg, Strength::WEAK)
       .JumpIfFalse(&start);
   // Perform an operation that returns a non-boolean operation to
   // generate JumpIfToBooleanTrue/False.
   builder.BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
       .JumpIfTrue(&start)
       .BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
       .JumpIfFalse(&start);
 
-  builder.EnterBlock()
-      .Throw()
-      .LeaveBlock();
+  // Emit throw in it's own basic block so that the rest of the code isn't
+  // omitted due to being dead.
+  BytecodeLabel after_throw;
+  builder.Jump(&after_throw)
+    .Throw()
+    .Bind(&after_throw);
 
   builder.ForInPrepare(reg).ForInDone(reg).ForInNext(reg, reg);
 
   // Wide constant pool loads
   for (int i = 0; i < 256; i++) {
     // Emit junk in constant pool to force wide constant pool index.
     builder.GetConstantPoolEntry(handle(Smi::FromInt(i), isolate()));
   }
   builder.LoadLiteral(Smi::FromInt(20000000));
 
@@ skipping 275 matching lines @@
 TEST_F(BytecodeArrayBuilderTest, BackwardJumps) {
   BytecodeArrayBuilder builder(isolate(), zone());
   builder.set_parameter_count(0);
   builder.set_locals_count(1);
   builder.set_context_count(0);
   Register reg(0);
 
   BytecodeLabel label0, label1, label2, label3, label4;
   builder.Bind(&label0)
       .Jump(&label0)
+      .Bind(&label1)
       .CompareOperation(Token::Value::EQ, reg, Strength::WEAK)
-      .Bind(&label1)
       .JumpIfTrue(&label1)
+      .Bind(&label2)
       .CompareOperation(Token::Value::EQ, reg, Strength::WEAK)
-      .Bind(&label2)
       .JumpIfFalse(&label2)
+      .Bind(&label3)
       .BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
-      .Bind(&label3)
       .JumpIfTrue(&label3)
+      .Bind(&label4)
       .BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
-      .Bind(&label4)
       .JumpIfFalse(&label4);
-  for (int i = 0; i < 64; i++) {
+  for (int i = 0; i < 63; i++) {
     builder.Jump(&label4);
   }
   builder.BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
       .JumpIfFalse(&label4);
   builder.BinaryOperation(Token::Value::ADD, reg, Strength::WEAK)
       .JumpIfTrue(&label3);
   builder.CompareOperation(Token::Value::EQ, reg, Strength::WEAK)
       .JumpIfFalse(&label2);
   builder.CompareOperation(Token::Value::EQ, reg, Strength::WEAK)
       .JumpIfTrue(&label1);
   builder.Jump(&label0);
   builder.Return();
 
   Handle<BytecodeArray> array = builder.ToBytecodeArray();
   BytecodeArrayIterator iterator(array);
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJump);
   CHECK_EQ(iterator.GetImmediateOperand(0), 0);
   iterator.Advance();
   // Ignore compare operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfTrue);
-  CHECK_EQ(iterator.GetImmediateOperand(0), 0);
+  CHECK_EQ(iterator.GetImmediateOperand(0), -2);
   iterator.Advance();
   // Ignore compare operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfFalse);
-  CHECK_EQ(iterator.GetImmediateOperand(0), 0);
+  CHECK_EQ(iterator.GetImmediateOperand(0), -2);
   iterator.Advance();
   // Ignore binary operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfToBooleanTrue);
-  CHECK_EQ(iterator.GetImmediateOperand(0), 0);
+  CHECK_EQ(iterator.GetImmediateOperand(0), -2);
   iterator.Advance();
   // Ignore binary operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfToBooleanFalse);
-  CHECK_EQ(iterator.GetImmediateOperand(0), 0);
+  CHECK_EQ(iterator.GetImmediateOperand(0), -2);
   iterator.Advance();
-  for (int i = 0; i < 64; i++) {
+  for (int i = 0; i < 63; i++) {
     CHECK_EQ(iterator.current_bytecode(), Bytecode::kJump);
-    CHECK_EQ(iterator.GetImmediateOperand(0), -i * 2 - 2);
+    CHECK_EQ(iterator.GetImmediateOperand(0), -i * 2 - 4);
     iterator.Advance();
   }
   // Ignore binary operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(),
            Bytecode::kJumpIfToBooleanFalseConstant);
   CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -132);
   iterator.Advance();
   // Ignore binary operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfToBooleanTrueConstant);
   CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -140);
   iterator.Advance();
   // Ignore compare operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfFalseConstant);
   CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -148);
   iterator.Advance();
   // Ignore compare operation.
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfTrueConstant);
   CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -156);
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpConstant);
-  CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -162);
+  CHECK_EQ(Smi::cast(*iterator.GetConstantForIndexOperand(0))->value(), -160);
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kReturn);
   iterator.Advance();
   CHECK(iterator.done());
 }
 
 
 TEST_F(BytecodeArrayBuilderTest, LabelReuse) {
   BytecodeArrayBuilder builder(isolate(), zone());
   builder.set_parameter_count(0);
@@ skipping 56 matching lines @@
   CHECK(iterator.done());
 }
 
 
 TEST_F(BytecodeArrayBuilderTest, ToBoolean) {
   BytecodeArrayBuilder builder(isolate(), zone());
   builder.set_parameter_count(0);
   builder.set_locals_count(0);
   builder.set_context_count(0);
 
-  // Check ToBoolean emitted at start of block.
-  builder.EnterBlock().CastAccumulatorToBoolean();
+  // Check ToBoolean emitted at start of a basic block.
+  builder.CastAccumulatorToBoolean();
 
   // Check ToBoolean emitted preceding bytecode is non-boolean.
   builder.LoadNull().CastAccumulatorToBoolean();
 
   // Check ToBoolean omitted if preceding bytecode is boolean.
   builder.LoadFalse().CastAccumulatorToBoolean();
 
-  // Check ToBoolean emitted if it is at the start of the next block.
+  // Check ToBoolean emitted if it is at the start of a basic block caused by a
+  // bound label.
+  BytecodeLabel label;
   builder.LoadFalse()
-      .LeaveBlock()
-      .EnterBlock()
-      .CastAccumulatorToBoolean()
-      .LeaveBlock();
+      .Bind(&label)
+      .CastAccumulatorToBoolean();
+
+  // Check ToBoolean emitted if it is at the start of a basic block caused by a
+  // jump.
+  builder.LoadFalse()
+      .JumpIfTrue(&label)
+      .CastAccumulatorToBoolean();
 
   builder.Return();
 
   Handle<BytecodeArray> array = builder.ToBytecodeArray();
   BytecodeArrayIterator iterator(array);
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kToBoolean);
   iterator.Advance();
 
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kLdaNull);
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kToBoolean);
   iterator.Advance();
 
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kLdaFalse);
   iterator.Advance();
 
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kLdaFalse);
   iterator.Advance();
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kToBoolean);
   iterator.Advance();
 
+  CHECK_EQ(iterator.current_bytecode(), Bytecode::kLdaFalse);
+  iterator.Advance();
+  CHECK_EQ(iterator.current_bytecode(), Bytecode::kJumpIfTrue);
+  iterator.Advance();
+  CHECK_EQ(iterator.current_bytecode(), Bytecode::kToBoolean);
+  iterator.Advance();
+
   CHECK_EQ(iterator.current_bytecode(), Bytecode::kReturn);
   iterator.Advance();
   CHECK(iterator.done());
 }
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8