static void stepOverInstruction(CodeBlock* codeBlock, BytecodeBasicBlock* block, Vector<std::unique_ptr<BytecodeBasicBlock>>& basicBlocks, unsigned bytecodeOffset, const UseFunctor& use, const DefFunctor& def)
{
// This abstractly execute the instruction in reverse. Instructions logically first use operands and
// then define operands. This logical ordering is necessary for operations that use and def the same
// operand, like:
//
// op_add loc1, loc1, loc2
//
// The use of loc1 happens before the def of loc1. That's a semantic requirement since the add
// operation cannot travel forward in time to read the value that it will produce after reading that
// value. Since we are executing in reverse, this means that we must do defs before uses (reverse of
// uses before defs).
//
// Since this is a liveness analysis, this ordering ends up being particularly important: if we did
// uses before defs, then the add operation above would appear to not have loc1 live, since we'd
// first add it to the out set (the use), and then we'd remove it (the def).
computeDefsForBytecodeOffset(
codeBlock, block, bytecodeOffset,
[&] (CodeBlock* codeBlock, Instruction*, OpcodeID, int operand) {
if (isValidRegisterForLiveness(codeBlock, operand))
def(VirtualRegister(operand).toLocal());
});
computeUsesForBytecodeOffset(
codeBlock, block, bytecodeOffset,
[&] (CodeBlock* codeBlock, Instruction*, OpcodeID, int operand) {
if (isValidRegisterForLiveness(codeBlock, operand))
use(VirtualRegister(operand).toLocal());
});
// If we have an exception handler, we want the live-in variables of the
// exception handler block to be included in the live-in of this particular bytecode.
if (HandlerInfo* handler = codeBlock->handlerForBytecodeOffset(bytecodeOffset)) {
// FIXME: This resume check should not be needed.
// https://bugs.webkit.org/show_bug.cgi?id=159281
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
Instruction* instruction = &instructionsBegin[bytecodeOffset];
OpcodeID opcodeID = interpreter->getOpcodeID(instruction->u.opcode);
if (opcodeID != op_resume) {
BytecodeBasicBlock* handlerBlock = findBasicBlockWithLeaderOffset(basicBlocks, handler->target);
ASSERT(handlerBlock);
handlerBlock->in().forEachSetBit(use);
}
}
}
static void setForOperand(CodeBlock* codeBlock, FastBitVector& bits, int operand)
{
ASSERT(isValidRegisterForLiveness(codeBlock, operand));
VirtualRegister virtualReg(operand);
if (virtualReg.offset() > captureStart(codeBlock))
bits.set(virtualReg.toLocal());
else
bits.set(virtualReg.toLocal() - numberOfCapturedVariables(codeBlock));
}
static void computeUsesForBytecodeOffset(CodeBlock* codeBlock, unsigned bytecodeOffset, FastBitVector& uses)
{
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
Instruction* instruction = &instructionsBegin[bytecodeOffset];
OpcodeID opcodeID = interpreter->getOpcodeID(instruction->u.opcode);
switch (opcodeID) {
// No uses.
case op_new_regexp:
case op_new_array_buffer:
case op_throw_static_error:
case op_debug:
case op_resolve_scope:
case op_pop_scope:
case op_jneq_ptr:
case op_new_func_exp:
case op_loop_hint:
case op_jmp:
case op_new_object:
case op_init_lazy_reg:
case op_get_callee:
case op_enter:
case op_catch:
return;
// First argument.
case op_new_func:
case op_create_activation:
case op_create_arguments:
case op_to_this:
case op_tear_off_activation:
case op_profile_will_call:
case op_profile_did_call:
case op_throw:
case op_push_with_scope:
case op_end:
case op_ret:
case op_jtrue:
case op_jfalse:
case op_jeq_null:
case op_jneq_null:
case op_dec:
case op_inc: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
return;
}
// First and second arguments.
case op_del_by_id:
case op_ret_object_or_this:
case op_jlesseq:
case op_jgreater:
case op_jgreatereq:
case op_jnless:
case op_jnlesseq:
case op_jngreater:
case op_jngreatereq:
case op_jless: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
return;
}
// First, second, and third arguments.
case op_del_by_val:
case op_put_by_val_direct:
case op_put_by_val: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
return;
}
// First and third arguments.
case op_put_by_index:
case op_put_by_id_replace:
case op_put_by_id_transition:
case op_put_by_id_transition_direct:
case op_put_by_id_transition_direct_out_of_line:
case op_put_by_id_transition_normal:
case op_put_by_id_transition_normal_out_of_line:
case op_put_by_id_generic:
case op_put_by_id_out_of_line:
case op_put_by_id:
case op_put_to_scope: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
return;
}
// First, third, and fourth arguments.
case op_put_getter_setter: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[4].u.operand))
setForOperand(codeBlock, uses, instruction[4].u.operand);
return;
}
// Second argument.
case op_init_global_const_nop:
case op_init_global_const:
case op_push_name_scope:
case op_get_from_scope:
case op_to_primitive:
case op_get_by_id:
case op_get_by_id_out_of_line:
case op_get_by_id_self:
case op_get_by_id_proto:
case op_get_by_id_chain:
case op_get_by_id_getter_self:
case op_get_by_id_getter_proto:
case op_get_by_id_getter_chain:
case op_get_by_id_custom_self:
case op_get_by_id_custom_proto:
case op_get_by_id_custom_chain:
case op_get_by_id_generic:
case op_get_array_length:
case op_get_string_length:
case op_get_arguments_length:
case op_typeof:
case op_is_undefined:
case op_is_boolean:
case op_is_number:
case op_is_string:
case op_is_object:
case op_is_function:
case op_to_number:
case op_negate:
case op_neq_null:
case op_eq_null:
case op_not:
case op_mov:
case op_new_array_with_size:
case op_create_this: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
return;
}
// Second and third arguments.
case op_get_by_val:
case op_get_argument_by_val:
case op_in:
case op_instanceof:
case op_check_has_instance:
case op_add:
case op_mul:
case op_div:
case op_mod:
case op_sub:
case op_lshift:
case op_rshift:
case op_urshift:
case op_bitand:
case op_bitxor:
case op_bitor:
case op_less:
case op_lesseq:
case op_greater:
case op_greatereq:
case op_nstricteq:
case op_stricteq:
case op_neq:
case op_eq: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
return;
}
// Second, third, and fourth arguments.
case op_call_varargs:
case op_get_pnames: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[4].u.operand))
setForOperand(codeBlock, uses, instruction[4].u.operand);
return;
}
// Second, third, fourth, and fifth arguments.
case op_next_pname: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[4].u.operand))
setForOperand(codeBlock, uses, instruction[4].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[5].u.operand))
setForOperand(codeBlock, uses, instruction[5].u.operand);
return;
}
// Second, third, fourth, fifth, and sixth arguments.
case op_get_by_pname: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[4].u.operand))
setForOperand(codeBlock, uses, instruction[4].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[5].u.operand))
setForOperand(codeBlock, uses, instruction[5].u.operand);
if (isValidRegisterForLiveness(codeBlock, instruction[6].u.operand))
setForOperand(codeBlock, uses, instruction[6].u.operand);
return;
}
// Third argument.
case op_switch_string:
case op_switch_char:
case op_switch_imm: {
if (isValidRegisterForLiveness(codeBlock, instruction[3].u.operand))
setForOperand(codeBlock, uses, instruction[3].u.operand);
return;
}
// Variable number of arguments.
case op_new_array:
case op_strcat: {
int base = instruction[2].u.operand;
int count = instruction[3].u.operand;
for (int i = 0; i < count; i++) {
if (isValidRegisterForLiveness(codeBlock, base + i))
setForOperand(codeBlock, uses, base + i);
}
return;
}
// Crazy stuff for calls.
case op_construct:
case op_call_eval:
case op_call: {
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
int argCount = instruction[3].u.operand;
int registerOffset = instruction[4].u.operand;
int lastArg = registerOffset + CallFrame::thisArgumentOffset();
for (int i = 0; i < argCount; i++) {
if (isValidRegisterForLiveness(codeBlock, lastArg - i))
setForOperand(codeBlock, uses, lastArg - i);
}
return;
}
// Special stuff for tear off arguments.
case op_tear_off_arguments: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, uses, instruction[1].u.operand);
if (isValidRegisterForLiveness(codeBlock, unmodifiedArgumentsRegister(VirtualRegister(instruction[1].u.operand)).offset()))
setForOperand(codeBlock, uses, unmodifiedArgumentsRegister(VirtualRegister(instruction[1].u.operand)).offset());
if (isValidRegisterForLiveness(codeBlock, instruction[2].u.operand))
setForOperand(codeBlock, uses, instruction[2].u.operand);
return;
}
#define LLINT_HELPER_OPCODES(opcode, length) case opcode:
FOR_EACH_LLINT_OPCODE_EXTENSION(LLINT_HELPER_OPCODES)
return;
#undef LLINT_HELPER_OPCODES
}
}
static void computeDefsForBytecodeOffset(CodeBlock* codeBlock, unsigned bytecodeOffset, FastBitVector& defs)
{
Interpreter* interpreter = codeBlock->vm()->interpreter;
Instruction* instructionsBegin = codeBlock->instructions().begin();
Instruction* instruction = &instructionsBegin[bytecodeOffset];
OpcodeID opcodeID = interpreter->getOpcodeID(instruction->u.opcode);
switch (opcodeID) {
// These don't define anything.
case op_init_global_const:
case op_init_global_const_nop:
case op_push_name_scope:
case op_push_with_scope:
case op_put_to_scope:
case op_pop_scope:
case op_end:
case op_profile_will_call:
case op_profile_did_call:
case op_throw:
case op_throw_static_error:
case op_debug:
case op_ret:
case op_ret_object_or_this:
case op_jmp:
case op_jtrue:
case op_jfalse:
case op_jeq_null:
case op_jneq_null:
case op_jneq_ptr:
case op_jless:
case op_jlesseq:
case op_jgreater:
case op_jgreatereq:
case op_jnless:
case op_jnlesseq:
case op_jngreater:
case op_jngreatereq:
case op_loop_hint:
case op_switch_imm:
case op_switch_char:
case op_switch_string:
case op_put_by_id:
case op_put_by_id_out_of_line:
case op_put_by_id_replace:
case op_put_by_id_transition:
case op_put_by_id_transition_direct:
case op_put_by_id_transition_direct_out_of_line:
case op_put_by_id_transition_normal:
case op_put_by_id_transition_normal_out_of_line:
case op_put_by_id_generic:
case op_put_getter_setter:
case op_put_by_val:
case op_put_by_val_direct:
case op_put_by_index:
case op_del_by_id:
case op_del_by_val:
#define LLINT_HELPER_OPCODES(opcode, length) case opcode:
FOR_EACH_LLINT_OPCODE_EXTENSION(LLINT_HELPER_OPCODES);
#undef LLINT_HELPER_OPCODES
return;
// These all have a single destination for the first argument.
case op_next_pname:
case op_get_pnames:
case op_resolve_scope:
case op_strcat:
case op_tear_off_activation:
case op_to_primitive:
case op_catch:
case op_create_this:
case op_new_array:
case op_new_array_buffer:
case op_new_array_with_size:
case op_new_regexp:
case op_new_func:
case op_new_func_exp:
case op_call_varargs:
case op_get_from_scope:
case op_call:
case op_call_eval:
case op_construct:
case op_get_by_id:
case op_get_by_id_out_of_line:
case op_get_by_id_self:
case op_get_by_id_proto:
case op_get_by_id_chain:
case op_get_by_id_getter_self:
case op_get_by_id_getter_proto:
case op_get_by_id_getter_chain:
case op_get_by_id_custom_self:
case op_get_by_id_custom_proto:
case op_get_by_id_custom_chain:
case op_get_by_id_generic:
case op_get_array_length:
case op_get_string_length:
case op_check_has_instance:
case op_instanceof:
case op_get_by_val:
case op_get_argument_by_val:
case op_get_by_pname:
case op_get_arguments_length:
case op_typeof:
case op_is_undefined:
case op_is_boolean:
case op_is_number:
case op_is_string:
case op_is_object:
case op_is_function:
case op_in:
case op_to_number:
case op_negate:
case op_add:
case op_mul:
case op_div:
case op_mod:
case op_sub:
case op_lshift:
case op_rshift:
case op_urshift:
case op_bitand:
case op_bitxor:
case op_bitor:
case op_inc:
case op_dec:
case op_eq:
case op_neq:
case op_stricteq:
case op_nstricteq:
case op_less:
case op_lesseq:
case op_greater:
case op_greatereq:
case op_neq_null:
case op_eq_null:
case op_not:
case op_mov:
case op_new_object:
case op_to_this:
case op_get_callee:
case op_init_lazy_reg:
case op_create_activation:
case op_create_arguments: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand))
setForOperand(codeBlock, defs, instruction[1].u.operand);
return;
}
case op_tear_off_arguments: {
if (isValidRegisterForLiveness(codeBlock, instruction[1].u.operand - 1))
setForOperand(codeBlock, defs, instruction[1].u.operand - 1);
return;
}
case op_enter: {
defs.setAll();
return;
}
}
}
