Emily Bernier | d0a1eb7 | 2015-03-24 16:35:39 -0400 | [diff] [blame^] | 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/v8.h" |
| 6 | |
| 7 | #include "src/arguments.h" |
| 8 | #include "src/frames-inl.h" |
| 9 | #include "src/runtime/runtime-utils.h" |
| 10 | |
| 11 | namespace v8 { |
| 12 | namespace internal { |
| 13 | |
| 14 | RUNTIME_FUNCTION(Runtime_CreateJSGeneratorObject) { |
| 15 | HandleScope scope(isolate); |
| 16 | DCHECK(args.length() == 0); |
| 17 | |
| 18 | JavaScriptFrameIterator it(isolate); |
| 19 | JavaScriptFrame* frame = it.frame(); |
| 20 | Handle<JSFunction> function(frame->function()); |
| 21 | RUNTIME_ASSERT(function->shared()->is_generator()); |
| 22 | |
| 23 | Handle<JSGeneratorObject> generator; |
| 24 | if (frame->IsConstructor()) { |
| 25 | generator = handle(JSGeneratorObject::cast(frame->receiver())); |
| 26 | } else { |
| 27 | generator = isolate->factory()->NewJSGeneratorObject(function); |
| 28 | } |
| 29 | generator->set_function(*function); |
| 30 | generator->set_context(Context::cast(frame->context())); |
| 31 | generator->set_receiver(frame->receiver()); |
| 32 | generator->set_continuation(0); |
| 33 | generator->set_operand_stack(isolate->heap()->empty_fixed_array()); |
| 34 | generator->set_stack_handler_index(-1); |
| 35 | |
| 36 | return *generator; |
| 37 | } |
| 38 | |
| 39 | |
| 40 | RUNTIME_FUNCTION(Runtime_SuspendJSGeneratorObject) { |
| 41 | HandleScope handle_scope(isolate); |
| 42 | DCHECK(args.length() == 1); |
| 43 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator_object, 0); |
| 44 | |
| 45 | JavaScriptFrameIterator stack_iterator(isolate); |
| 46 | JavaScriptFrame* frame = stack_iterator.frame(); |
| 47 | RUNTIME_ASSERT(frame->function()->shared()->is_generator()); |
| 48 | DCHECK_EQ(frame->function(), generator_object->function()); |
| 49 | |
| 50 | // The caller should have saved the context and continuation already. |
| 51 | DCHECK_EQ(generator_object->context(), Context::cast(frame->context())); |
| 52 | DCHECK_LT(0, generator_object->continuation()); |
| 53 | |
| 54 | // We expect there to be at least two values on the operand stack: the return |
| 55 | // value of the yield expression, and the argument to this runtime call. |
| 56 | // Neither of those should be saved. |
| 57 | int operands_count = frame->ComputeOperandsCount(); |
| 58 | DCHECK_GE(operands_count, 2); |
| 59 | operands_count -= 2; |
| 60 | |
| 61 | if (operands_count == 0) { |
| 62 | // Although it's semantically harmless to call this function with an |
| 63 | // operands_count of zero, it is also unnecessary. |
| 64 | DCHECK_EQ(generator_object->operand_stack(), |
| 65 | isolate->heap()->empty_fixed_array()); |
| 66 | DCHECK_EQ(generator_object->stack_handler_index(), -1); |
| 67 | // If there are no operands on the stack, there shouldn't be a handler |
| 68 | // active either. |
| 69 | DCHECK(!frame->HasHandler()); |
| 70 | } else { |
| 71 | int stack_handler_index = -1; |
| 72 | Handle<FixedArray> operand_stack = |
| 73 | isolate->factory()->NewFixedArray(operands_count); |
| 74 | frame->SaveOperandStack(*operand_stack, &stack_handler_index); |
| 75 | generator_object->set_operand_stack(*operand_stack); |
| 76 | generator_object->set_stack_handler_index(stack_handler_index); |
| 77 | } |
| 78 | |
| 79 | return isolate->heap()->undefined_value(); |
| 80 | } |
| 81 | |
| 82 | |
| 83 | // Note that this function is the slow path for resuming generators. It is only |
| 84 | // called if the suspended activation had operands on the stack, stack handlers |
| 85 | // needing rewinding, or if the resume should throw an exception. The fast path |
| 86 | // is handled directly in FullCodeGenerator::EmitGeneratorResume(), which is |
| 87 | // inlined into GeneratorNext and GeneratorThrow. EmitGeneratorResumeResume is |
| 88 | // called in any case, as it needs to reconstruct the stack frame and make space |
| 89 | // for arguments and operands. |
| 90 | RUNTIME_FUNCTION(Runtime_ResumeJSGeneratorObject) { |
| 91 | SealHandleScope shs(isolate); |
| 92 | DCHECK(args.length() == 3); |
| 93 | CONVERT_ARG_CHECKED(JSGeneratorObject, generator_object, 0); |
| 94 | CONVERT_ARG_CHECKED(Object, value, 1); |
| 95 | CONVERT_SMI_ARG_CHECKED(resume_mode_int, 2); |
| 96 | JavaScriptFrameIterator stack_iterator(isolate); |
| 97 | JavaScriptFrame* frame = stack_iterator.frame(); |
| 98 | |
| 99 | DCHECK_EQ(frame->function(), generator_object->function()); |
| 100 | DCHECK(frame->function()->is_compiled()); |
| 101 | |
| 102 | STATIC_ASSERT(JSGeneratorObject::kGeneratorExecuting < 0); |
| 103 | STATIC_ASSERT(JSGeneratorObject::kGeneratorClosed == 0); |
| 104 | |
| 105 | Address pc = generator_object->function()->code()->instruction_start(); |
| 106 | int offset = generator_object->continuation(); |
| 107 | DCHECK(offset > 0); |
| 108 | frame->set_pc(pc + offset); |
| 109 | if (FLAG_enable_ool_constant_pool) { |
| 110 | frame->set_constant_pool( |
| 111 | generator_object->function()->code()->constant_pool()); |
| 112 | } |
| 113 | generator_object->set_continuation(JSGeneratorObject::kGeneratorExecuting); |
| 114 | |
| 115 | FixedArray* operand_stack = generator_object->operand_stack(); |
| 116 | int operands_count = operand_stack->length(); |
| 117 | if (operands_count != 0) { |
| 118 | frame->RestoreOperandStack(operand_stack, |
| 119 | generator_object->stack_handler_index()); |
| 120 | generator_object->set_operand_stack(isolate->heap()->empty_fixed_array()); |
| 121 | generator_object->set_stack_handler_index(-1); |
| 122 | } |
| 123 | |
| 124 | JSGeneratorObject::ResumeMode resume_mode = |
| 125 | static_cast<JSGeneratorObject::ResumeMode>(resume_mode_int); |
| 126 | switch (resume_mode) { |
| 127 | case JSGeneratorObject::NEXT: |
| 128 | return value; |
| 129 | case JSGeneratorObject::THROW: |
| 130 | return isolate->Throw(value); |
| 131 | } |
| 132 | |
| 133 | UNREACHABLE(); |
| 134 | return isolate->ThrowIllegalOperation(); |
| 135 | } |
| 136 | |
| 137 | |
| 138 | RUNTIME_FUNCTION(Runtime_GeneratorClose) { |
| 139 | HandleScope scope(isolate); |
| 140 | DCHECK(args.length() == 1); |
| 141 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 142 | |
| 143 | generator->set_continuation(JSGeneratorObject::kGeneratorClosed); |
| 144 | |
| 145 | return isolate->heap()->undefined_value(); |
| 146 | } |
| 147 | |
| 148 | |
| 149 | // Returns function of generator activation. |
| 150 | RUNTIME_FUNCTION(Runtime_GeneratorGetFunction) { |
| 151 | HandleScope scope(isolate); |
| 152 | DCHECK(args.length() == 1); |
| 153 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 154 | |
| 155 | return generator->function(); |
| 156 | } |
| 157 | |
| 158 | |
| 159 | // Returns context of generator activation. |
| 160 | RUNTIME_FUNCTION(Runtime_GeneratorGetContext) { |
| 161 | HandleScope scope(isolate); |
| 162 | DCHECK(args.length() == 1); |
| 163 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 164 | |
| 165 | return generator->context(); |
| 166 | } |
| 167 | |
| 168 | |
| 169 | // Returns receiver of generator activation. |
| 170 | RUNTIME_FUNCTION(Runtime_GeneratorGetReceiver) { |
| 171 | HandleScope scope(isolate); |
| 172 | DCHECK(args.length() == 1); |
| 173 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 174 | |
| 175 | return generator->receiver(); |
| 176 | } |
| 177 | |
| 178 | |
| 179 | // Returns generator continuation as a PC offset, or the magic -1 or 0 values. |
| 180 | RUNTIME_FUNCTION(Runtime_GeneratorGetContinuation) { |
| 181 | HandleScope scope(isolate); |
| 182 | DCHECK(args.length() == 1); |
| 183 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 184 | |
| 185 | return Smi::FromInt(generator->continuation()); |
| 186 | } |
| 187 | |
| 188 | |
| 189 | RUNTIME_FUNCTION(Runtime_GeneratorGetSourcePosition) { |
| 190 | HandleScope scope(isolate); |
| 191 | DCHECK(args.length() == 1); |
| 192 | CONVERT_ARG_HANDLE_CHECKED(JSGeneratorObject, generator, 0); |
| 193 | |
| 194 | if (generator->is_suspended()) { |
| 195 | Handle<Code> code(generator->function()->code(), isolate); |
| 196 | int offset = generator->continuation(); |
| 197 | |
| 198 | RUNTIME_ASSERT(0 <= offset && offset < code->Size()); |
| 199 | Address pc = code->address() + offset; |
| 200 | |
| 201 | return Smi::FromInt(code->SourcePosition(pc)); |
| 202 | } |
| 203 | |
| 204 | return isolate->heap()->undefined_value(); |
| 205 | } |
| 206 | |
| 207 | |
| 208 | RUNTIME_FUNCTION(Runtime_FunctionIsGenerator) { |
| 209 | SealHandleScope shs(isolate); |
| 210 | DCHECK(args.length() == 1); |
| 211 | CONVERT_ARG_CHECKED(JSFunction, f, 0); |
| 212 | return isolate->heap()->ToBoolean(f->shared()->is_generator()); |
| 213 | } |
| 214 | |
| 215 | |
| 216 | RUNTIME_FUNCTION(RuntimeReference_GeneratorNext) { |
| 217 | UNREACHABLE(); // Optimization disabled in SetUpGenerators(). |
| 218 | return NULL; |
| 219 | } |
| 220 | |
| 221 | |
| 222 | RUNTIME_FUNCTION(RuntimeReference_GeneratorThrow) { |
| 223 | UNREACHABLE(); // Optimization disabled in SetUpGenerators(). |
| 224 | return NULL; |
| 225 | } |
| 226 | } |
| 227 | } // namespace v8::internal |