diff options
author | Lars Knoll <lars.knoll@qt.io> | 2017-05-10 09:42:18 +0200 |
---|---|---|
committer | Lars Knoll <lars.knoll@qt.io> | 2017-05-19 06:23:01 +0000 |
commit | 7ed93899e9305ccd538361ee58baa4bf15ff8a41 (patch) | |
tree | e5de061ca2b93cb5d9673bb0d5ffbcab1c5607d2 /src/qml/compiler | |
parent | 2affe19182b99d8d1c9655fa0c58c8af3e0b9506 (diff) |
Optimizations to the generated byte code
Cut the size of the generated byte code in half, by storing
parameters in a more compact form and always storing the
instruction type in the instruction.
We can still used computed goto's for a fast interpreter, by
looking up the jump point for the next instruction in the jump
table.
Another advantage is that the byte code is now platform independent
(modulo endianness).
The change comes with a 3% performance impact on x86_64, which
is acceptable considering the size savings on the bytecode.
Change-Id: I37de3e1f94611987a85e65ea86536583aa965d6d
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Diffstat (limited to 'src/qml/compiler')
-rw-r--r-- | src/qml/compiler/qv4instr_moth_p.h | 10 | ||||
-rw-r--r-- | src/qml/compiler/qv4isel_moth.cpp | 55 |
2 files changed, 3 insertions, 62 deletions
diff --git a/src/qml/compiler/qv4instr_moth_p.h b/src/qml/compiler/qv4instr_moth_p.h index fbd6ac8f99..dabda7bae8 100644 --- a/src/qml/compiler/qv4instr_moth_p.h +++ b/src/qml/compiler/qv4instr_moth_p.h @@ -170,11 +170,7 @@ QT_BEGIN_NAMESPACE #define MOTH_INSTR_ALIGN_MASK (Q_ALIGNOF(QV4::Moth::Instr) - 1) -#ifdef MOTH_THREADED_INTERPRETER -# define MOTH_INSTR_HEADER union { quint32 instructionType; void *code; }; -#else -# define MOTH_INSTR_HEADER quint32 instructionType; -#endif +#define MOTH_INSTR_HEADER quint32 instructionType; #define MOTH_INSTR_ENUM(I, FMT) I, #define MOTH_INSTR_SIZE(I, FMT) ((sizeof(QV4::Moth::Instr::instr_##FMT) + MOTH_INSTR_ALIGN_MASK) & ~MOTH_INSTR_ALIGN_MASK) @@ -194,8 +190,8 @@ struct Param { // Arg(outer): 4 // Local(outer): 5 // ... - unsigned scope; - unsigned index; + unsigned scope : 12; + unsigned index : 20; bool isConstant() const { return !scope; } bool isArgument() const { return scope >= 2 && !(scope &1); } diff --git a/src/qml/compiler/qv4isel_moth.cpp b/src/qml/compiler/qv4isel_moth.cpp index dc6fe317e5..fb805dce02 100644 --- a/src/qml/compiler/qv4isel_moth.cpp +++ b/src/qml/compiler/qv4isel_moth.cpp @@ -1436,29 +1436,6 @@ CompilationUnit::~CompilationUnit() void CompilationUnit::linkBackendToEngine(QV4::ExecutionEngine *engine) { -#ifdef MOTH_THREADED_INTERPRETER - // link byte code against addresses of instructions - for (int i = 0; i < codeRefs.count(); ++i) { - QByteArray &codeRef = codeRefs[i]; - char *code = codeRef.data(); - int index = 0; - while (index < codeRef.size()) { - Instr *genericInstr = reinterpret_cast<Instr *>(code + index); - - switch (genericInstr->common.instructionType) { -#define LINK_INSTRUCTION(InstructionType, Member) \ - case Instr::InstructionType: \ - genericInstr->common.code = VME::instructionJumpTable()[static_cast<int>(genericInstr->common.instructionType)]; \ - index += InstrMeta<(int)Instr::InstructionType>::Size; \ - break; - - FOR_EACH_MOTH_INSTR(LINK_INSTRUCTION) - - } - } - } -#endif - runtimeFunctions.resize(data->functionTableSize); runtimeFunctions.fill(0); for (int i = 0 ;i < runtimeFunctions.size(); ++i) { @@ -1516,17 +1493,6 @@ bool CompilationUnit::saveCodeToDisk(QIODevice *device, const CompiledData::Unit QByteArray padding; -#if defined(MOTH_THREADED_INTERPRETER) && !defined(V4_BOOTSTRAP) - // Map from instruction label back to instruction type. Only needed when persisting - // already linked compilation units; - QHash<void*, int> reverseInstructionMapping; - if (engine) { - void **instructions = VME::instructionJumpTable(); - for (int i = 0; i < Instr::LastInstruction; ++i) - reverseInstructionMapping.insert(instructions[i], i); - } -#endif - for (int i = 0; i < codeRefs.size(); ++i) { const CompiledData::Function *compiledFunction = unit->functionAt(i); @@ -1545,27 +1511,6 @@ bool CompilationUnit::saveCodeToDisk(QIODevice *device, const CompiledData::Unit QByteArray code = codeRefs.at(i); -#if defined(MOTH_THREADED_INTERPRETER) && !defined(V4_BOOTSTRAP) - if (!reverseInstructionMapping.isEmpty()) { - char *codePtr = code.data(); // detaches - int index = 0; - while (index < code.size()) { - Instr *genericInstr = reinterpret_cast<Instr *>(codePtr + index); - - genericInstr->common.instructionType = reverseInstructionMapping.value(genericInstr->common.code); - - switch (genericInstr->common.instructionType) { - #define REVERSE_INSTRUCTION(InstructionType, Member) \ - case Instr::InstructionType: \ - index += InstrMeta<(int)Instr::InstructionType>::Size; \ - break; - - FOR_EACH_MOTH_INSTR(REVERSE_INSTRUCTION) - } - } - } -#endif - written = device->write(code.constData(), compiledFunction->codeSize); if (written != qint64(compiledFunction->codeSize)) { *errorString = device->errorString(); |