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ladybird/Userland/Libraries/LibJS/Bytecode/Generator.h

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LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
/*
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
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.
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#include <AK/NonnullOwnPtrVector.h>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
#include <AK/OwnPtr.h>
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.
2021-06-09 06:49:58 +04:30
#include <AK/SinglyLinkedList.h>
#include <LibJS/Bytecode/BasicBlock.h>
LibJS: Make ASTNode::generate_bytecode() fallible Instead of crashing on the spot, return a descriptive error that will eventually continue its days as a javascript "InternalError" exception. This should make random crashes with BC less likely.
2022-02-12 19:54:08 +03:30
#include <LibJS/Bytecode/CodeGenerationError.h>
LibJS: Add Bytecode::Executable::dump() Let's have a helper for producing a consistent executable dump instead of repeating the logic in multiple places.
2021-10-24 13:30:49 +02:00
#include <LibJS/Bytecode/Executable.h>
LibJS: Add a separate "identifier table" to bytecode executables This is a specialized string table for storing identifiers only. Identifiers are always FlyStrings, which makes many common operations faster by allowing O(1) comparison.
2021-10-24 15:34:30 +02:00
#include <LibJS/Bytecode/IdentifierTable.h>
LibJS: Add basic support for while loops in the bytecode engine This introduces two new instructions: Jump and JumpIfFalse. Jumps are made to a Bytecode::Label, which is a simple object that represents a location in the bytecode stream. Note that you may not always know the target of a jump when adding the jump instruction itself, but we can just update the instruction later on during codegen once we know where the jump target is. The Bytecode::Interpreter now implements jumping via a jump slot that gets checked after each instruction to see if a jump is pending. If not, we just increment the PC as usual.
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#include <LibJS/Bytecode/Label.h>
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
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#include <LibJS/Bytecode/Op.h>
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
#include <LibJS/Bytecode/Register.h>
LibJS: Store strings in a string table Instead of using Strings in the bytecode ops this adds a global string table to the Executable struct which individual operations can refer to using indices. This brings bytecode ops one step closer to being pointer free.
2021-06-09 10:02:01 +02:00
#include <LibJS/Bytecode/StringTable.h>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
#include <LibJS/Forward.h>
LibJS: Implement async functions as generator functions in BC mode This applies a simple transformation, and adds a simple wrapper that translates the generator interface to the async function interface.
2021-11-11 00:46:07 +03:30
#include <LibJS/Runtime/FunctionKind.h>
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
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namespace JS::Bytecode {
class Generator {
public:
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
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enum class SurroundingScopeKind {
Global,
Function,
Block,
};
LibJS: Make ASTNode::generate_bytecode() fallible Instead of crashing on the spot, return a descriptive error that will eventually continue its days as a javascript "InternalError" exception. This should make random crashes with BC less likely.
2022-02-12 19:54:08 +03:30
static CodeGenerationErrorOr<NonnullOwnPtr<Executable>> generate(ASTNode const&, FunctionKind = FunctionKind::Normal);
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
Register allocate_register();
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
void ensure_enough_space(size_t size)
{
// Make sure there's always enough space for a single jump at the end.
if (!m_current_basic_block->can_grow(size + sizeof(Op::Jump))) {
auto& new_block = make_block();
emit<Op::Jump>().set_targets(
Label { new_block },
{});
switch_to_basic_block(new_block);
}
}
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
template<typename OpType, typename... Args>
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
OpType& emit(Args&&... args)
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
{
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.
2021-06-09 06:49:58 +04:30
VERIFY(!is_current_block_terminated());
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
// If the block doesn't have enough space, switch to another block
if constexpr (!OpType::IsTerminator)
ensure_enough_space(sizeof(OpType));
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
void* slot = next_slot();
grow(sizeof(OpType));
new (slot) OpType(forward<Args>(args)...);
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.
2021-06-09 06:49:58 +04:30
if constexpr (OpType::IsTerminator)
m_current_basic_block->terminate({});
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
return *static_cast<OpType*>(slot);
LibJS: Devirtualize and pack the bytecode stream :^) This patch changes the LibJS bytecode to be a stream of instructions packed one-after-the-other in contiguous memory, instead of a vector of OwnPtr<Instruction>. This should be a lot more cache-friendly. :^) Instructions are also devirtualized and instead have a type field using a new Instruction::Type enum. To iterate over a bytecode stream, one must now use Bytecode::InstructionStreamIterator.
2021-06-07 15:12:43 +02:00
}
template<typename OpType, typename... Args>
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
OpType& emit_with_extra_register_slots(size_t extra_register_slots, Args&&... args)
LibJS: Devirtualize and pack the bytecode stream :^) This patch changes the LibJS bytecode to be a stream of instructions packed one-after-the-other in contiguous memory, instead of a vector of OwnPtr<Instruction>. This should be a lot more cache-friendly. :^) Instructions are also devirtualized and instead have a type field using a new Instruction::Type enum. To iterate over a bytecode stream, one must now use Bytecode::InstructionStreamIterator.
2021-06-07 15:12:43 +02:00
{
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.
2021-06-09 06:49:58 +04:30
VERIFY(!is_current_block_terminated());
LibJS: Align Instructions as void* and roundup variably sized ones sizes Both is indeed needed, the standard alignment would have been 4, but some Instructions, like Jumps need an alignment of 8 Fixes #12127.
2022-09-09 16:47:42 +02:00
size_t size_to_allocate = round_up_to_power_of_two(sizeof(OpType) + extra_register_slots * sizeof(Register), alignof(void*));
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
// If the block doesn't have enough space, switch to another block
if constexpr (!OpType::IsTerminator)
LibJS: Align Instructions as void* and roundup variably sized ones sizes Both is indeed needed, the standard alignment would have been 4, but some Instructions, like Jumps need an alignment of 8 Fixes #12127.
2022-09-09 16:47:42 +02:00
ensure_enough_space(size_to_allocate);
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
void* slot = next_slot();
LibJS: Align Instructions as void* and roundup variably sized ones sizes Both is indeed needed, the standard alignment would have been 4, but some Instructions, like Jumps need an alignment of 8 Fixes #12127.
2022-09-09 16:47:42 +02:00
grow(size_to_allocate);
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
new (slot) OpType(forward<Args>(args)...);
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.
2021-06-09 06:49:58 +04:30
if constexpr (OpType::IsTerminator)
m_current_basic_block->terminate({});
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
return *static_cast<OpType*>(slot);
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
}
LibJS: Make ASTNode::generate_bytecode() fallible Instead of crashing on the spot, return a descriptive error that will eventually continue its days as a javascript "InternalError" exception. This should make random crashes with BC less likely.
2022-02-12 19:54:08 +03:30
CodeGenerationErrorOr<void> emit_load_from_reference(JS::ASTNode const&);
CodeGenerationErrorOr<void> emit_store_to_reference(JS::ASTNode const&);
LibJS/Bytecode: Implement the delete unary expression `delete` has to operate directly on Reference Records, so this introduces a new set of operations called DeleteByValue, DeleteVariable and DeleteById. They operate similarly to their Get counterparts, except they end in creating a (temporary) Reference and calling delete_ on it.
2022-03-27 19:50:09 +01:00
CodeGenerationErrorOr<void> emit_delete_reference(JS::ASTNode const&);
LibJS: Add BytecodeGenerator helpers for reference get/put This allows code sharing between all AST nodes that want to get and/or put through a reference.
2021-10-25 15:16:22 +02:00
LibJS/Bytecode: Implement break/continue labels This is done by keeping track of all the labels that apply to a given break/continue scope alongside their bytecode target. When a break/continue with a label is generated, we scan from the most inner scope to the most outer scope looking for the label, performing any necessary unwinds on the way. Once the label is found, it is then jumped to.
2022-06-11 23:09:37 +01:00
void begin_continuable_scope(Label continue_target, Vector<FlyString> const& language_label_set);
LibJS: Add basic support for "continue" in the bytecode VM Unlike the convoluted unwind-until-scope-type mechanism in the AST interpreter, "continue" maps to a simple Bytecode::Op::Jump here. :^) We know where to jump based on a stack of "continuable scopes" that we now maintain on the Bytecode::Generator as we go. Note that this only supports bare "continue", not continue-with-label.
2021-06-06 13:33:02 +02:00
void end_continuable_scope();
LibJS/Bytecode: Implement break/continue labels This is done by keeping track of all the labels that apply to a given break/continue scope alongside their bytecode target. When a break/continue with a label is generated, we scan from the most inner scope to the most outer scope looking for the label, performing any necessary unwinds on the way. Once the label is found, it is then jumped to.
2022-06-11 23:09:37 +01:00
void begin_breakable_scope(Label breakable_target, Vector<FlyString> const& language_label_set);
LibJS: Implement bytecode generation for BreakStatement
2021-06-10 20:28:43 +08:00
void end_breakable_scope();
LibJS: Add basic support for "continue" in the bytecode VM Unlike the convoluted unwind-until-scope-type mechanism in the AST interpreter, "continue" maps to a simple Bytecode::Op::Jump here. :^) We know where to jump based on a stack of "continuable scopes" that we now maintain on the Bytecode::Generator as we go. Note that this only supports bare "continue", not continue-with-label.
2021-06-06 13:33:02 +02:00
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.
2021-06-09 06:49:58 +04:30
[[nodiscard]] Label nearest_continuable_scope() const;
LibJS: Implement bytecode generation for BreakStatement
2021-06-10 20:28:43 +08:00
[[nodiscard]] Label nearest_breakable_scope() const;
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.
2021-06-09 06:49:58 +04:30
void switch_to_basic_block(BasicBlock& block)
{
m_current_basic_block = &block;
}
LibJS: Implement bytecode generation for try..catch..finally EnterUnwindContext pushes an unwind context (exception handler and/or finalizer) onto a stack. LeaveUnwindContext pops the unwind context from that stack. Upon return to the interpreter loop we check whether the VM has an exception pending. If no unwind context is available we return from the loop. If an exception handler is available we clear the VM's exception, put the exception value into the accumulator register, clear the unwind context's handler and jump to the handler. If no handler is available but a finalizer is available we save the exception value + metadata (for later use by ContinuePendingUnwind), clear the VM's exception, pop the unwind context and jump to the finalizer. ContinuePendingUnwind checks whether a saved exception is available. If no saved exception is available it jumps to the resume label. Otherwise it stores the exception into the VM. The Jump after LeaveUnwindContext could be integrated into the LeaveUnwindContext instruction. I've kept them separate for now to make the bytecode more readable. > try { 1; throw "x" } catch (e) { 2 } finally { 3 }; 4 1: [ 0] EnterScope [ 10] EnterUnwindContext handler:@4 finalizer:@3 [ 38] EnterScope [ 48] LoadImmediate 1 [ 60] NewString 1 ("x") [ 70] Throw <for non-terminated blocks: insert LeaveUnwindContext + Jump @3 here> 2: [ 0] LoadImmediate 4 3: [ 0] EnterScope [ 10] LoadImmediate 3 [ 28] ContinuePendingUnwind resume:@2 4: [ 0] SetVariable 0 (e) [ 10] EnterScope [ 20] LoadImmediate 2 [ 38] LeaveUnwindContext [ 3c] Jump @3 String Table: 0: e 1: x
2021-06-10 15:04:38 +02:00
[[nodiscard]] BasicBlock& current_block() { return *m_current_basic_block; }
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.
2021-06-09 06:49:58 +04:30
BasicBlock& make_block(String name = {})
{
if (name.is_empty())
name = String::number(m_next_block++);
m_root_basic_blocks.append(BasicBlock::create(name));
return m_root_basic_blocks.last();
}
bool is_current_block_terminated() const
{
return m_current_basic_block->is_terminated();
}
LibJS: Add basic support for "continue" in the bytecode VM Unlike the convoluted unwind-until-scope-type mechanism in the AST interpreter, "continue" maps to a simple Bytecode::Op::Jump here. :^) We know where to jump based on a stack of "continuable scopes" that we now maintain on the Bytecode::Generator as we go. Note that this only supports bare "continue", not continue-with-label.
2021-06-06 13:33:02 +02:00
LibJS: Use String and move semantics in Bytecode::StringTable Avoid creating new AK::String objects when we already have one.
2021-10-24 15:14:14 +02:00
StringTableIndex intern_string(String string)
LibJS: Store strings in a string table Instead of using Strings in the bytecode ops this adds a global string table to the Executable struct which individual operations can refer to using indices. This brings bytecode ops one step closer to being pointer free.
2021-06-09 10:02:01 +02:00
{
LibJS: Use String and move semantics in Bytecode::StringTable Avoid creating new AK::String objects when we already have one.
2021-10-24 15:14:14 +02:00
return m_string_table->insert(move(string));
LibJS: Store strings in a string table Instead of using Strings in the bytecode ops this adds a global string table to the Executable struct which individual operations can refer to using indices. This brings bytecode ops one step closer to being pointer free.
2021-06-09 10:02:01 +02:00
}
LibJS: Add a separate "identifier table" to bytecode executables This is a specialized string table for storing identifiers only. Identifiers are always FlyStrings, which makes many common operations faster by allowing O(1) comparison.
2021-10-24 15:34:30 +02:00
IdentifierTableIndex intern_identifier(FlyString string)
{
return m_identifier_table->insert(move(string));
}
LibJS: Implement async functions as generator functions in BC mode This applies a simple transformation, and adds a simple wrapper that translates the generator interface to the async function interface.
2021-11-11 00:46:07 +03:30
bool is_in_generator_or_async_function() const { return m_enclosing_function_kind == FunctionKind::Async || m_enclosing_function_kind == FunctionKind::Generator; }
bool is_in_generator_function() const { return m_enclosing_function_kind == FunctionKind::Generator; }
bool is_in_async_function() const { return m_enclosing_function_kind == FunctionKind::Async; }
LibJS: Implement generator functions (only in bytecode mode)
2021-06-11 01:38:30 +04:30
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
2022-02-12 19:48:45 +03:30
enum class BindingMode {
Lexical,
Var,
Global,
};
struct LexicalScope {
SurroundingScopeKind kind;
BindingMode mode;
HashTable<IdentifierTableIndex> known_bindings;
};
void register_binding(IdentifierTableIndex identifier, BindingMode mode = BindingMode::Lexical)
{
m_variable_scopes.last_matching([&](auto& x) { return x.mode == BindingMode::Global || x.mode == mode; })->known_bindings.set(identifier);
}
LibJS/Bytecode: Check for lexical bindings only in current scope BlockDeclarationInstantiation takes as input the new lexical environment that was created and checks if there is a binding for the current name only in this new scope. This allows shadowing lexical variables and prevents us crashing due to an already initialized lexical variable in this case: ```js let x = 1; { let x = 1; } ```
2022-07-17 19:09:19 +01:00
bool has_binding(IdentifierTableIndex identifier, Optional<BindingMode> const& specific_binding_mode = {}) const
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
2022-02-12 19:48:45 +03:30
{
for (auto index = m_variable_scopes.size(); index > 0; --index) {
auto& scope = m_variable_scopes[index - 1];
if (scope.mode != BindingMode::Global && specific_binding_mode.value_or(scope.mode) != scope.mode)
continue;
if (scope.known_bindings.contains(identifier))
return true;
}
return false;
}
LibJS/Bytecode: Check for lexical bindings only in current scope BlockDeclarationInstantiation takes as input the new lexical environment that was created and checks if there is a binding for the current name only in this new scope. This allows shadowing lexical variables and prevents us crashing due to an already initialized lexical variable in this case: ```js let x = 1; { let x = 1; } ```
2022-07-17 19:09:19 +01:00
bool has_binding_in_current_scope(IdentifierTableIndex identifier) const
{
if (m_variable_scopes.is_empty())
return false;
return m_variable_scopes.last().known_bindings.contains(identifier);
}
LibJS/Bytecode: Unwind environments before block terminating instruction When we reach a block terminating instruction (e.g. Break, Throw), we cannot generate anymore instructions after it. This would not allow us to leave any lexical/variable environments. This uses the mechanism introduced in ba9c49 to unwind environments when we encounter these instructions.
2022-03-14 02:34:01 +00:00
void begin_variable_scope(BindingMode mode = BindingMode::Lexical, SurroundingScopeKind kind = SurroundingScopeKind::Block);
void end_variable_scope();
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
2022-02-12 19:48:45 +03:30
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
enum class BlockBoundaryType {
Break,
Continue,
Unwind,
LibJS/Bytecode: Unwind environments before block terminating instruction When we reach a block terminating instruction (e.g. Break, Throw), we cannot generate anymore instructions after it. This would not allow us to leave any lexical/variable environments. This uses the mechanism introduced in ba9c49 to unwind environments when we encounter these instructions.
2022-03-14 02:34:01 +00:00
LeaveLexicalEnvironment,
LeaveVariableEnvironment,
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
};
template<typename OpType>
void perform_needed_unwinds(bool is_break_node = false) requires(OpType::IsTerminator)
{
Optional<BlockBoundaryType> boundary_to_stop_at;
if constexpr (IsSame<OpType, Bytecode::Op::Return> || IsSame<OpType, Bytecode::Op::Yield>)
VERIFY(!is_break_node);
LibJS/Bytecode: Unwind to closest unwind boundary on Throw This will leave any lexical/variable environments on the way to the closest unwind context boundary. This will not leave the closest unwind context, as we still need the unwind context to perform the Throw instruction correctly.
2022-03-14 02:26:39 +00:00
else if constexpr (IsSame<OpType, Bytecode::Op::Throw>)
boundary_to_stop_at = BlockBoundaryType::Unwind;
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
else
boundary_to_stop_at = is_break_node ? BlockBoundaryType::Break : BlockBoundaryType::Continue;
for (size_t i = m_boundaries.size(); i > 0; --i) {
auto boundary = m_boundaries[i - 1];
if (boundary_to_stop_at.has_value() && boundary == *boundary_to_stop_at)
break;
if (boundary == BlockBoundaryType::Unwind)
emit<Bytecode::Op::LeaveUnwindContext>();
LibJS/Bytecode: Unwind environments before block terminating instruction When we reach a block terminating instruction (e.g. Break, Throw), we cannot generate anymore instructions after it. This would not allow us to leave any lexical/variable environments. This uses the mechanism introduced in ba9c49 to unwind environments when we encounter these instructions.
2022-03-14 02:34:01 +00:00
else if (boundary == BlockBoundaryType::LeaveLexicalEnvironment)
emit<Bytecode::Op::LeaveEnvironment>(Bytecode::Op::EnvironmentMode::Lexical);
else if (boundary == BlockBoundaryType::LeaveVariableEnvironment)
emit<Bytecode::Op::LeaveEnvironment>(Bytecode::Op::EnvironmentMode::Var);
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
}
}
LibJS/Bytecode: Implement break/continue labels This is done by keeping track of all the labels that apply to a given break/continue scope alongside their bytecode target. When a break/continue with a label is generated, we scan from the most inner scope to the most outer scope looking for the label, performing any necessary unwinds on the way. Once the label is found, it is then jumped to.
2022-06-11 23:09:37 +01:00
Label perform_needed_unwinds_for_labelled_break_and_return_target_block(FlyString const& break_label);
Label perform_needed_unwinds_for_labelled_continue_and_return_target_block(FlyString const& continue_label);
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
void start_boundary(BlockBoundaryType type) { m_boundaries.append(type); }
void end_boundary(BlockBoundaryType type)
{
VERIFY(m_boundaries.last() == type);
m_boundaries.take_last();
}
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
private:
Generator();
Libraries: Use default constructors/destructors in LibJS https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#cother-other-default-operation-rules "The compiler is more likely to get the default semantics right and you cannot implement these functions better than the compiler."
2022-03-14 10:25:06 -06:00
~Generator() = default;
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
Revert "LibJS: Add bytecode instruction handles" This reverts commit a01bd35c67e35e9f0e33f46bb3a4431e49af1b60. This broke simple programs like: function sum(a, b) { return a + b; } console.log(sum(1, 2));
2021-06-09 00:50:42 +02:00
void grow(size_t);
void* next_slot();
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
LibJS/Bytecode: Implement break/continue labels This is done by keeping track of all the labels that apply to a given break/continue scope alongside their bytecode target. When a break/continue with a label is generated, we scan from the most inner scope to the most outer scope looking for the label, performing any necessary unwinds on the way. Once the label is found, it is then jumped to.
2022-06-11 23:09:37 +01:00
struct LabelableScope {
Label bytecode_target;
Vector<FlyString> language_label_set;
};
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.
2021-06-09 06:49:58 +04:30
BasicBlock* m_current_basic_block { nullptr };
NonnullOwnPtrVector<BasicBlock> m_root_basic_blocks;
LibJS: Store strings in a string table Instead of using Strings in the bytecode ops this adds a global string table to the Executable struct which individual operations can refer to using indices. This brings bytecode ops one step closer to being pointer free.
2021-06-09 10:02:01 +02:00
NonnullOwnPtr<StringTable> m_string_table;
LibJS: Add a separate "identifier table" to bytecode executables This is a specialized string table for storing identifiers only. Identifiers are always FlyStrings, which makes many common operations faster by allowing O(1) comparison.
2021-10-24 15:34:30 +02:00
NonnullOwnPtr<IdentifierTable> m_identifier_table;
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.
2021-06-09 06:49:58 +04:30
LibJS: Always keep the global object in bytecode VM register $1
2021-06-10 01:07:53 +02:00
u32 m_next_register { 2 };
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.
2021-06-09 06:49:58 +04:30
u32 m_next_block { 1 };
LibJS: Rename FunctionKind::{Regular => Normal} This is what CreateDynamicFunction calls it.
2022-01-15 00:30:02 +01:00
FunctionKind m_enclosing_function_kind { FunctionKind::Normal };
LibJS/Bytecode: Implement break/continue labels This is done by keeping track of all the labels that apply to a given break/continue scope alongside their bytecode target. When a break/continue with a label is generated, we scan from the most inner scope to the most outer scope looking for the label, performing any necessary unwinds on the way. Once the label is found, it is then jumped to.
2022-06-11 23:09:37 +01:00
Vector<LabelableScope> m_continuable_scopes;
Vector<LabelableScope> m_breakable_scopes;
LibJS: More properly implement scoping rules in bytecode codegen Now we emit CreateVariable and SetVariable with the appropriate initialization/environment modes, much closer to the spec. This makes a whole lot of things like let/const variables, function and variable hoisting and some other things work :^)
2022-02-12 19:48:45 +03:30
Vector<LexicalScope> m_variable_scopes;
LibJS: Leave the unwind context on break/continue/return in bytecode Otherwise we'd keep the old unwind context, and end up never invoking the other handlers up the stack.
2022-03-13 11:51:02 +03:30
Vector<BlockBoundaryType> m_boundaries;
LibJS: Start fleshing out a bytecode for the JavaScript engine :^) This patch begins the work of implementing JavaScript execution in a bytecode VM instead of an AST tree-walk interpreter. It's probably quite naive, but we have to start somewhere. The basic idea is that you call Bytecode::Generator::generate() on an AST node and it hands you back a Bytecode::Block filled with instructions that can then be interpreted by a Bytecode::Interpreter. This first version only implements two instructions: Load and Add. :^) Each bytecode block has infinity registers, and the interpreter resizes its register file to fit the block being executed. Two new `js` options are added in this patch as well: `-d` will dump the generated bytecode `-b` will execute the generated bytecode Note that unless `-d` and/or `-b` are specified, none of the bytecode related stuff in LibJS runs at all. This is implemented in parallel with the existing AST interpreter. :^)
2021-06-03 10:46:30 +02:00
};
}
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