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Revert "LibJS: Add bytecode instruction handles"

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This reverts commit a01bd35c67.

This broke simple programs like:

function sum(a, b) { return a + b; }
console.log(sum(1, 2));
This commit is contained in:
Andreas Kling 2021-06-09 00:50:42 +02:00
parent a01bd35c67
commit b8a5ea1f8d
8 changed files with 79 additions and 81 deletions
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28
Userland/Libraries/LibJS/Bytecode/Block.cpp
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@ -4,8 +4,10 @@
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/String.h>
#include <LibJS/Bytecode/Block.h>
#include <LibJS/Bytecode/Op.h>
#include <sys/mman.h>
namespace JS::Bytecode {
@ -14,6 +16,16 @@ NonnullOwnPtr<Block> Block::create()
return adopt_own(*new Block);
}
Block::Block()
{
// FIXME: This is not the smartest solution ever. Find something cleverer!
// The main issue we're working around here is that we don't want pointers into the bytecode stream to become invalidated
// during code generation due to dynamic buffer resizing. Otherwise we could just use a Vector.
m_buffer_capacity = 64 * KiB;
m_buffer = (u8*)mmap(nullptr, m_buffer_capacity, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
VERIFY(m_buffer != MAP_FAILED);
}
Block::~Block()
{
Bytecode::InstructionStreamIterator it(instruction_stream());
@ -22,6 +34,16 @@ Block::~Block()
++it;
Instruction::destroy(const_cast<Instruction&>(to_destroy));
}
munmap(m_buffer, m_buffer_capacity);
}
void Block::seal()
{
// FIXME: mprotect the instruction stream as PROT_READ
// This is currently not possible because instructions can have destructors (that clean up strings)
// Instructions should instead be destructor-less and refer to strings in a string table on the Bytecode::Block.
// It also doesn't work because instructions that have String members use RefPtr internally which must be in writable memory.
}
void Block::dump() const
@ -33,6 +55,12 @@ void Block::dump() const
}
}
void Block::grow(size_t additional_size)
{
m_buffer_size += additional_size;
VERIFY(m_buffer_size <= m_buffer_capacity);
}
void InstructionStreamIterator::operator++()
{
m_offset += dereference().length();