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LibJS: Generate bytecode in basic blocks instead of one big block

This limits the size of each block (currently set to 1K), and gets us
closer to a canonical, more easily analysable bytecode format.
As a result of this, "Labels" are now simply entries to basic blocks.
Since there is no more 'conditional' jump (as all jumps are always
taken), JumpIf{True,False} are unified to JumpConditional, and
JumpIfNullish is renamed to JumpNullish.
Also fixes #7914 as a result of reimplementing the loop logic.
This commit is contained in:
Ali Mohammad Pur 2021-06-09 06:49:58 +04:30 committed by Andreas Kling
parent d7a25cdb82
commit 01e8f0889a
16 changed files with 392 additions and 174 deletions

View file

@ -5,7 +5,7 @@
*/
#include <AK/Debug.h>
#include <LibJS/Bytecode/Block.h>
#include <LibJS/Bytecode/BasicBlock.h>
#include <LibJS/Bytecode/Instruction.h>
#include <LibJS/Bytecode/Interpreter.h>
#include <LibJS/Runtime/GlobalObject.h>
@ -33,9 +33,9 @@ Interpreter::~Interpreter()
s_current = nullptr;
}
Value Interpreter::run(Bytecode::Block const& block)
Value Interpreter::run(ExecutionUnit const& execution_unit)
{
dbgln_if(JS_BYTECODE_DEBUG, "Bytecode::Interpreter will run block {:p}", &block);
dbgln_if(JS_BYTECODE_DEBUG, "Bytecode::Interpreter will run unit {:p}", &execution_unit);
CallFrame global_call_frame;
if (vm().call_stack().is_empty()) {
@ -50,23 +50,37 @@ Value Interpreter::run(Bytecode::Block const& block)
VERIFY(!vm().exception());
}
auto block = &execution_unit.basic_blocks.first();
m_register_windows.append(make<RegisterWindow>());
registers().resize(block.register_count());
registers().resize(execution_unit.number_of_registers);
Bytecode::InstructionStreamIterator pc(block.instruction_stream());
while (!pc.at_end()) {
auto& instruction = *pc;
instruction.execute(*this);
if (m_pending_jump.has_value()) {
pc.jump(m_pending_jump.release_value());
continue;
for (;;) {
Bytecode::InstructionStreamIterator pc(block->instruction_stream());
bool will_jump = false;
bool will_return = false;
while (!pc.at_end()) {
auto& instruction = *pc;
instruction.execute(*this);
if (m_pending_jump.has_value()) {
block = m_pending_jump.release_value();
will_jump = true;
break;
}
if (!m_return_value.is_empty()) {
will_return = true;
break;
}
++pc;
}
if (!m_return_value.is_empty())
if (will_return)
break;
if (pc.at_end() && !will_jump)
break;
++pc;
}
dbgln_if(JS_BYTECODE_DEBUG, "Bytecode::Interpreter did run block {:p}", &block);
dbgln_if(JS_BYTECODE_DEBUG, "Bytecode::Interpreter did run unit {:p}", &execution_unit);
if constexpr (JS_BYTECODE_DEBUG) {
for (size_t i = 0; i < registers().size(); ++i) {