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ladybird/Userland/Libraries/LibJS/Bytecode/BasicBlock.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
#include <AK/Badge.h>
AK+Everywhere: Rename String to DeprecatedString We have a new, improved string type coming up in AK (OOM aware, no null state), and while it's going to use UTF-8, the name UTF8String is a mouthful - so let's free up the String name by renaming the existing class. Making the old one have an annoying name will hopefully also help with quick adoption :^)
2022-12-04 18:02:33 +00:00
#include <AK/DeprecatedString.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/Bytecode: Restore old environments when an exception is caught Unwind contexts now remember the lexical and variable environments in effect when they were created. If an exception is caught, we revert to those environments in the running execution context.
2023-05-13 18:53:14 +02:00
#include <LibJS/Heap/Handle.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
namespace JS::Bytecode {
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
struct UnwindInfo {
LibJS: Propagate exceptions across bytecode executable boundaries To support situations like this: function foo() { throw 1; } try { foo(); } catch (e) { } Each unwind context now keeps track of its origin executable. When an exception is thrown, we return from run() immediately if the nearest unwind context isn't in the current executable. This causes a natural unwind to the point where we find the catch/finally block(s) to jump into.
2021-10-25 12:30:54 +02:00
Executable const* executable;
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
BasicBlock const* handler;
BasicBlock const* finalizer;
LibJS/Bytecode: Restore old environments when an exception is caught Unwind contexts now remember the lexical and variable environments in effect when they were created. If an exception is caught, we revert to those environments in the running execution context.
2023-05-13 18:53:14 +02:00
Handle<Environment> lexical_environment;
Handle<Environment> variable_environment;
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
};
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
class BasicBlock {
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
AK_MAKE_NONCOPYABLE(BasicBlock);
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
public:
AK+Everywhere: Rename String to DeprecatedString We have a new, improved string type coming up in AK (OOM aware, no null state), and while it's going to use UTF-8, the name UTF8String is a mouthful - so let's free up the String name by renaming the existing class. Making the old one have an annoying name will hopefully also help with quick adoption :^)
2022-12-04 18:02:33 +00:00
static NonnullOwnPtr<BasicBlock> create(DeprecatedString name, size_t size = 4 * KiB);
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();
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 seal();
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
void dump(Executable const&) const;
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
ReadonlyBytes instruction_stream() const { return ReadonlyBytes { m_buffer, m_buffer_size }; }
LibJS: Make basic block size customizable And keep the default 4 KiB for the code generator.
2021-06-12 20:36:39 +04:30
size_t size() const { return m_buffer_size; }
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* next_slot() { return m_buffer + m_buffer_size; }
LibJS: Automatically split linear bytecode into multiple blocks ...instead of crashing :^)
2021-06-11 01:35:01 +04:30
bool can_grow(size_t additional_size) const { return m_buffer_size + additional_size <= m_buffer_capacity; }
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 additional_size);
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: Remeber which instruction terminated a block
2022-11-26 14:42:36 +01:00
void terminate(Badge<Generator>, Instruction const* terminator) { m_terminator = terminator; }
bool is_terminated() const { return m_terminator != nullptr; }
Instruction const* terminator() const { return m_terminator; }
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
AK+Everywhere: Rename String to DeprecatedString We have a new, improved string type coming up in AK (OOM aware, no null state), and while it's going to use UTF-8, the name UTF8String is a mouthful - so let's free up the String name by renaming the existing class. Making the old one have an annoying name will hopefully also help with quick adoption :^)
2022-12-04 18:02:33 +00:00
DeprecatedString const& name() const { return m_name; }
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: 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:
AK+Everywhere: Rename String to DeprecatedString We have a new, improved string type coming up in AK (OOM aware, no null state), and while it's going to use UTF-8, the name UTF8String is a mouthful - so let's free up the String name by renaming the existing class. Making the old one have an annoying name will hopefully also help with quick adoption :^)
2022-12-04 18:02:33 +00:00
BasicBlock(DeprecatedString name, size_t size);
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
u8* m_buffer { nullptr };
LibJS: Remeber which instruction terminated a block
2022-11-26 14:42:36 +01:00
Instruction const* m_terminator { nullptr };
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
size_t m_buffer_capacity { 0 };
size_t m_buffer_size { 0 };
AK+Everywhere: Rename String to DeprecatedString We have a new, improved string type coming up in AK (OOM aware, no null state), and while it's going to use UTF-8, the name UTF8String is a mouthful - so let's free up the String name by renaming the existing class. Making the old one have an annoying name will hopefully also help with quick adoption :^)
2022-12-04 18:02:33 +00:00
DeprecatedString m_name;
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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