Changeset 183094 in webkit for trunk/Source/JavaScriptCore/dfg/DFGBasicBlock.cpp

Timestamp:

Apr 21, 2015, 8:38:17 PM (10 years ago)

Author:

[email protected]

Message:

DFG should allow Phantoms after terminals
​https://bugs.webkit.org/show_bug.cgi?id=126778

Reviewed by Mark Lam.

It's important for us to be able to place liveness-marking nodes after nodes that do
things. These liveness-marking nodes are nops. Previously, we disallowed such nodes after
terminals. That made things awkward, especially for Switch and Branch, which may do
things that necessitate liveness markers (for example they might want to use a converted
version of a value rather than the value that was MovHinted). We previously made this
work by disallowing certain optimizations on Switch and Branch, which was probably a bad
thing.

This changes our IR to allow for the terminal to not be the last node in a block. Asking
for the terminal involves a search. DFG::validate() checks that the nodes after the
terminal are liveness markers that have no effects or checks.

This is perf-neutral but will allow more optimizations in the future. It will also make
it cleaner to fix ​https://bugs.webkit.org/show_bug.cgi?id=143735.

• dfg/DFGBasicBlock.cpp:

(JSC::DFG::BasicBlock::replaceTerminal):

• dfg/DFGBasicBlock.h:

(JSC::DFG::BasicBlock::findTerminal):
(JSC::DFG::BasicBlock::terminal):
(JSC::DFG::BasicBlock::insertBeforeTerminal):
(JSC::DFG::BasicBlock::numSuccessors):
(JSC::DFG::BasicBlock::successor):
(JSC::DFG::BasicBlock::successorForCondition):
(JSC::DFG::BasicBlock::successors):
(JSC::DFG::BasicBlock::last): Deleted.
(JSC::DFG::BasicBlock::takeLast): Deleted.
(JSC::DFG::BasicBlock::insertBeforeLast): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::SuccessorsIterable): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::iterator::iterator): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::iterator::operator*): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::iterator::operator++): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::iterator::operator==): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::iterator::operator!=): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::begin): Deleted.
(JSC::DFG::BasicBlock::SuccessorsIterable::end): Deleted.

• dfg/DFGBasicBlockInlines.h:

(JSC::DFG::BasicBlock::appendNonTerminal):
(JSC::DFG::BasicBlock::replaceTerminal):

• dfg/DFGByteCodeParser.cpp:

(JSC::DFG::ByteCodeParser::addToGraph):
(JSC::DFG::ByteCodeParser::inlineCall):
(JSC::DFG::ByteCodeParser::handleInlining):
(JSC::DFG::ByteCodeParser::parseBlock):
(JSC::DFG::ByteCodeParser::linkBlock):
(JSC::DFG::ByteCodeParser::parseCodeBlock):

• dfg/DFGCFGSimplificationPhase.cpp:

(JSC::DFG::CFGSimplificationPhase::run):
(JSC::DFG::CFGSimplificationPhase::convertToJump):
(JSC::DFG::CFGSimplificationPhase::mergeBlocks):

• dfg/DFGCPSRethreadingPhase.cpp:

(JSC::DFG::CPSRethreadingPhase::canonicalizeLocalsInBlock):

• dfg/DFGCommon.h:

(JSC::DFG::NodeAndIndex::NodeAndIndex):
(JSC::DFG::NodeAndIndex::operator!):

• dfg/DFGFixupPhase.cpp:

(JSC::DFG::FixupPhase::fixupBlock):
(JSC::DFG::FixupPhase::fixupNode):
(JSC::DFG::FixupPhase::injectTypeConversionsInBlock):
(JSC::DFG::FixupPhase::clearPhantomsAtEnd): Deleted.

• dfg/DFGForAllKills.h:

(JSC::DFG::forAllLiveNodesAtTail):

• dfg/DFGGraph.cpp:

(JSC::DFG::Graph::terminalsAreValid):
(JSC::DFG::Graph::dumpBlockHeader):

• dfg/DFGGraph.h:
• dfg/DFGInPlaceAbstractState.cpp:

(JSC::DFG::InPlaceAbstractState::mergeToSuccessors):

• dfg/DFGLICMPhase.cpp:

(JSC::DFG::LICMPhase::run):
(JSC::DFG::LICMPhase::attemptHoist):

• dfg/DFGMovHintRemovalPhase.cpp:
• dfg/DFGNode.h:

(JSC::DFG::Node::SuccessorsIterable::SuccessorsIterable):
(JSC::DFG::Node::SuccessorsIterable::iterator::iterator):
(JSC::DFG::Node::SuccessorsIterable::iterator::operator*):
(JSC::DFG::Node::SuccessorsIterable::iterator::operator++):
(JSC::DFG::Node::SuccessorsIterable::iterator::operator==):
(JSC::DFG::Node::SuccessorsIterable::iterator::operator!=):
(JSC::DFG::Node::SuccessorsIterable::begin):
(JSC::DFG::Node::SuccessorsIterable::end):
(JSC::DFG::Node::successors):

• dfg/DFGObjectAllocationSinkingPhase.cpp:

(JSC::DFG::ObjectAllocationSinkingPhase::determineMaterializationPoints):
(JSC::DFG::ObjectAllocationSinkingPhase::placeMaterializationPoints):
(JSC::DFG::ObjectAllocationSinkingPhase::promoteSunkenFields):

• dfg/DFGPhantomRemovalPhase.cpp:

(JSC::DFG::PhantomRemovalPhase::run):

• dfg/DFGPutStackSinkingPhase.cpp:
• dfg/DFGSSAConversionPhase.cpp:

(JSC::DFG::SSAConversionPhase::run):

• dfg/DFGSpeculativeJIT.h:

(JSC::DFG::SpeculativeJIT::detectPeepHoleBranch):

• dfg/DFGSpeculativeJIT32_64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGSpeculativeJIT64.cpp:

(JSC::DFG::SpeculativeJIT::compile):

• dfg/DFGStaticExecutionCountEstimationPhase.cpp:

(JSC::DFG::StaticExecutionCountEstimationPhase::run):

• dfg/DFGTierUpCheckInjectionPhase.cpp:

(JSC::DFG::TierUpCheckInjectionPhase::run):

• dfg/DFGValidate.cpp:

(JSC::DFG::Validate::validate):

• ftl/FTLLowerDFGToLLVM.cpp:

(JSC::FTL::LowerDFGToLLVM::compileNode):

• tests/stress/closure-call-exit.js: Added.

(foo):

File:

• trunk/Source/JavaScriptCore/dfg/DFGBasicBlock.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/dfg/DFGBasicBlock.cpp

@@ -1 +1 @@
 /*
- * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
+ * Copyright (C) 2013-2015 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -70 +70 @@
     valuesAtTail.ensureLocals(newNumLocals);
     intersectionOfPastValuesAtHead.ensureLocals(newNumLocals, AbstractValue::fullTop());
+}
+
+void BasicBlock::replaceTerminal(Node* node)
+{
+    NodeAndIndex result = findTerminal();
+    if (!result)
+        append(node);
+    else {
+        m_nodes.insert(result.index + 1, node);
+        result.node->convertToPhantom();
+    }
+    
+    ASSERT(terminal());
 }