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ladybird/Libraries/LibJS/Bytecode/Label.h

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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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/*
Meta: Update my e-mail address everywhere
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* Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
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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*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
LibJS: Remove obsolete bytecode dump formatting helpers The Rust bytecode dumper now formats exception handler labels, raw operands, builtins, labels, and registers. Remove the C++ dump-only formatters and flatten Operand to expose only the runtime value-array layout that C++ still observes.
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#include <AK/Types.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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namespace JS::Bytecode {
LibJS: Revert Enable EXPLICIT_SYMBOL_EXPORT This reverts commit c14173f651f5a50fdb86beb4b79487454a00f3f6. We should only annotate the minimum number of symbols that external consumers actually use, so I am starting from scratch to do that
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class Label {
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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public:
LibJS: Remove unused C++ bytecode block classes The Rust bytecode generator now owns basic block construction. The old C++ BasicBlock class no longer has any users. Label no longer needs to translate from BasicBlock. Remove the now-empty Label.cpp from the build as well.
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explicit Label(u32 address)
: m_address(address)
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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{
}
LibJS: Remove unused C++ bytecode block classes The Rust bytecode generator now owns basic block construction. The old C++ BasicBlock class no longer has any users. Label no longer needs to translate from BasicBlock. Remove the now-empty Label.cpp from the build as well.
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size_t address() const { return m_address; }
LibJS/Bytecode: Flatten bytecode to a contiguous representation Instead of keeping bytecode as a set of disjoint basic blocks on the malloc heap, bytecode is now a contiguous sequence of bytes(!) The transformation happens at the end of Bytecode::Generator::generate() and the only really hairy part is rerouting jump labels. This required solving a few problems: - The interpreter execution loop had to change quite a bit, since we were storing BasicBlock pointers all over the place, and control transfer was done by redirecting the interpreter's current block. - Exception handlers & finalizers are now stored per-bytecode-range in a side table in Executable. - The interpreter now has a plain program counter instead of a stream iterator. This actually makes error stack generation a bit nicer since we just have to deal with a number instead of reaching into the iterator. This yields a 25% performance improvement on this microbenchmark: for (let i = 0; i < 1_000_000; ++i) { } But basically everything gets faster. :^)
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LibJS: Remove unused C++ bytecode block classes The Rust bytecode generator now owns basic block construction. The old C++ BasicBlock class no longer has any users. Label no longer needs to translate from BasicBlock. Remove the now-empty Label.cpp from the build as well.
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void set_address(size_t address) { m_address = address; }
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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private:
LibJS: Remove unused C++ bytecode block classes The Rust bytecode generator now owns basic block construction. The old C++ BasicBlock class no longer has any users. Label no longer needs to translate from BasicBlock. Remove the now-empty Label.cpp from the build as well.
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u32 m_address { 0 };
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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};
}
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