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LibJS/JIT: Dump disassembly of generated code using LibX86

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This avoids the need for redirecting stdout to a file and using
ndisasm, which can lead to problems if other things are printed.
This commit is contained in:
Simon Wanner 2023-10-23 18:37:29 +02:00 • committed by Andreas Kling
parent 1d68c64b98
commit ec8330b647
4 changed files with 48 additions and 1 deletions
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39
Userland/Libraries/LibJS/JIT/NativeExecutable.cpp
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@ -7,6 +7,7 @@
#include <LibJS/Bytecode/Interpreter.h>
#include <LibJS/JIT/NativeExecutable.h>
#include <LibJS/Runtime/VM.h>
#include <LibX86/Disassembler.h>
#include <sys/mman.h>
namespace JS::JIT {
@ -30,4 +31,42 @@ void NativeExecutable::run(VM& vm) const
vm.running_execution_context().local_variables.data());
}
void NativeExecutable::dump_disassembly() const
{
#if ARCH(X86_64)
auto const* code_bytes = static_cast<u8 const*>(m_code);
auto stream = X86::SimpleInstructionStream { code_bytes, m_size };
auto disassembler = X86::Disassembler(stream);
while (true) {
auto offset = stream.offset();
auto virtual_offset = bit_cast<size_t>(m_code) + offset;
auto insn = disassembler.next();
if (!insn.has_value())
break;
StringBuilder builder;
builder.appendff("{:p} ", virtual_offset);
auto length = insn.value().length();
for (size_t i = 0; i < 7; i++) {
if (i < length)
builder.appendff("{:02x} ", code_bytes[offset + i]);
else
builder.append(" "sv);
}
builder.append(" "sv);
builder.append(insn.value().to_deprecated_string(virtual_offset, nullptr));
dbgln("{}", builder.string_view());
for (size_t bytes_printed = 7; bytes_printed < length; bytes_printed += 7) {
builder.clear();
builder.appendff("{:p} ", virtual_offset + bytes_printed);
for (size_t i = bytes_printed; i < bytes_printed + 7 && i < length; i++)
builder.appendff(" {:02x}", code_bytes[offset + i]);
dbgln("{}", builder.string_view());
}
}
#endif
}
}