Changeset 275840 in webkit for trunk/Source/JavaScriptCore/bytecompiler

Timestamp:

Apr 12, 2021, 3:01:09 PM (4 years ago)

Author:

[email protected]

Message:

[JSC] Do not copy StringSwitchJumpTable
​https://bugs.webkit.org/show_bug.cgi?id=224414

Reviewed by Keith Miller.

Previously, we were copying UnlinkedStringJumpTable to CodeBlock's StringJumpTable because we embed CodeLocation pointer
inside CodeBlock's StringJumpTable. This is copying a mostly identical hashtable to each CodeBlock even in DFG and FTL. This
even prevents us from inlining op_switch_string in DFG and FTL because (1) we don't want to copy this string tables collected from
each inlined CodeBlock into a new DFG / FTL CodeBlock and (2) we cannot ref/deref StringImpl inside DFG / FTL compilers so copying
these tables in the compiler threads need additional "DesiredStringSwitchJumpTable" etc.

In this patch, we stop copying StringSwitchJumpTable. We decouple CodeLocation pointers from the hashtable so that we can use
UnlinkedStringJumpTable in UnlinkedCodeBlock. UnlinkedStringJumpTable's hashtable inclues m_indexInTable in each entry so that
we can have array of CodeLocation pointers in CodeBlock's JITData to have JIT jump targets separately. This design prevents us
from copying unnecessary hashtables, and even this paves the way to inlining switch_string in DFG and FTL.

• bytecode/BytecodeDumper.cpp:

(JSC::CodeBlockBytecodeDumper<Block>::dumpStringSwitchJumpTables):

• bytecode/CodeBlock.cpp:

(JSC::CodeBlock::finishCreation):
(JSC::CodeBlock::shrinkToFit):

• bytecode/CodeBlock.h:

(JSC::CodeBlock::stringSwitchJumpTable):
(JSC::CodeBlock::numberOfUnlinkedStringSwitchJumpTables const):
(JSC::CodeBlock::unlinkedStringSwitchJumpTable):
(JSC::CodeBlock::numberOfStringSwitchJumpTables const): Deleted.

• bytecode/JumpTable.h:

(JSC::StringJumpTable::ctiForValue const):
(JSC::StringJumpTable::offsetForValue): Deleted.
(JSC::StringJumpTable::ctiForValue): Deleted.
(JSC::StringJumpTable::clear): Deleted.

• bytecode/PreciseJumpTargetsInlines.h:
• bytecode/UnlinkedCodeBlock.h:

(JSC::UnlinkedStringJumpTable::offsetForValue const):
(JSC::UnlinkedCodeBlock::numberOfUnlinkedStringSwitchJumpTables const):
(JSC::UnlinkedCodeBlock::unlinkedStringSwitchJumpTable):
(JSC::UnlinkedStringJumpTable::offsetForValue): Deleted.
(JSC::UnlinkedCodeBlock::numberOfStringSwitchJumpTables const): Deleted.
(JSC::UnlinkedCodeBlock::stringSwitchJumpTable): Deleted.

• bytecode/UnlinkedCodeBlockGenerator.cpp:

(JSC::UnlinkedCodeBlockGenerator::finalize):

• bytecode/UnlinkedCodeBlockGenerator.h:

(JSC::UnlinkedCodeBlockGenerator::numberOfUnlinkedStringSwitchJumpTables const):
(JSC::UnlinkedCodeBlockGenerator::addUnlinkedStringSwitchJumpTable):
(JSC::UnlinkedCodeBlockGenerator::unlinkedStringSwitchJumpTable):
(JSC::UnlinkedCodeBlockGenerator::numberOfStringSwitchJumpTables const): Deleted.
(JSC::UnlinkedCodeBlockGenerator::addStringSwitchJumpTable): Deleted.
(JSC::UnlinkedCodeBlockGenerator::stringSwitchJumpTable): Deleted.

• bytecompiler/BytecodeGenerator.cpp:

(JSC::BytecodeGenerator::beginSwitch):
(JSC::prepareJumpTableForStringSwitch):
(JSC::BytecodeGenerator::endSwitch):

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::parseBlock):

• dfg/DFGJITCompiler.cpp:

(JSC::DFG::JITCompiler::link):

• dfg/DFGOperations.cpp:

(JSC::DFG::JSC_DEFINE_JIT_OPERATION):

• ftl/FTLLowerDFGToB3.cpp:

(JSC::FTL::DFG::LowerDFGToB3::switchStringSlow):

• ftl/FTLOperations.cpp:

(JSC::FTL::JSC_DEFINE_JIT_OPERATION):

• jit/JIT.cpp:

(JSC::JIT::link):

• jit/JIT.h:

(JSC::SwitchRecord::SwitchRecord):

• jit/JITOpcodes.cpp:

(JSC::JIT::emit_op_switch_string):

• jit/JITOpcodes32_64.cpp:

(JSC::JIT::emit_op_switch_string):

• jit/JITOperations.cpp:

(JSC::JSC_DEFINE_JIT_OPERATION):

• llint/LLIntSlowPaths.cpp:

(JSC::LLInt::LLINT_SLOW_PATH_DECL):

• runtime/CachedTypes.cpp:

(JSC::CachedStringJumpTable::encode):
(JSC::CachedStringJumpTable::decode const):
(JSC::CachedCodeBlockRareData::encode):
(JSC::CachedCodeBlockRareData::decode const):

File:

• trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp (modified) (3 diffs)

trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

@@ -4049 +4049 @@
     }
     case SwitchInfo::SwitchString: {
-        size_t tableIndex = m_codeBlock->numberOfStringSwitchJumpTables();
-        m_codeBlock->addStringSwitchJumpTable();
+        size_t tableIndex = m_codeBlock->numberOfUnlinkedStringSwitchJumpTables();
+        m_codeBlock->addUnlinkedStringSwitchJumpTable();
         OpSwitchString::emit(this, tableIndex, BoundLabel(), scrutineeRegister);
         break;
@@ -4112 +4112 @@
         ASSERT(nodes[i]->isString());
         StringImpl* clause = static_cast<StringNode*>(nodes[i])->value().impl();
-        jumpTable.offsetTable.add(clause, UnlinkedStringJumpTable::OffsetLocation { labels[i]->bind(switchAddress) });
+        auto result = jumpTable.m_offsetTable.add(clause, UnlinkedStringJumpTable::OffsetLocation { labels[i]->bind(switchAddress), 0 });
+        if (result.isNewEntry)
+            result.iterator->value.m_indexInTable = jumpTable.m_offsetTable.size() - 1;
     }
 }
@@ -4153 +4155 @@
         });
 
-        UnlinkedStringJumpTable& jumpTable = m_codeBlock->stringSwitchJumpTable(ref->as<OpSwitchString>().m_tableIndex);
+        UnlinkedStringJumpTable& jumpTable = m_codeBlock->unlinkedStringSwitchJumpTable(ref->as<OpSwitchString>().m_tableIndex);
         prepareJumpTableForStringSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes);
         break;