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Diffstat (limited to 'js/src/jit/WarpBuilder.h')
| -rw-r--r-- | js/src/jit/WarpBuilder.h | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/js/src/jit/WarpBuilder.h b/js/src/jit/WarpBuilder.h new file mode 100644 index 0000000000..2a92984f64 --- /dev/null +++ b/js/src/jit/WarpBuilder.h @@ -0,0 +1,323 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef jit_WarpBuilder_h +#define jit_WarpBuilder_h + +#include <initializer_list> + +#include "ds/InlineTable.h" +#include "jit/JitContext.h" +#include "jit/MIR.h" +#include "jit/WarpBuilderShared.h" +#include "jit/WarpSnapshot.h" +#include "vm/Opcodes.h" + +namespace js { +namespace jit { + +// JSOps not yet supported by WarpBuilder. See warning at the end of the list. +#define WARP_UNSUPPORTED_OPCODE_LIST(_) \ + /* Intentionally not implemented */ \ + _(ForceInterpreter) \ + /* With */ \ + _(EnterWith) \ + _(LeaveWith) \ + /* Eval */ \ + _(Eval) \ + _(StrictEval) \ + _(SpreadEval) \ + _(StrictSpreadEval) \ + /* Super */ \ + _(SetPropSuper) \ + _(SetElemSuper) \ + _(StrictSetPropSuper) \ + _(StrictSetElemSuper) \ + /* Compound assignment */ \ + _(GetBoundName) \ + /* Generators / Async (bug 1317690) */ \ + _(IsGenClosing) \ + _(Resume) \ + /* Misc */ \ + _(DelName) \ + _(SetIntrinsic) \ + /* Private Fields */ \ + _(GetAliasedDebugVar) \ + /* Non-syntactic scope */ \ + _(NonSyntacticGlobalThis) \ + /* Records and Tuples */ \ + IF_RECORD_TUPLE(_(InitRecord)) \ + IF_RECORD_TUPLE(_(AddRecordProperty)) \ + IF_RECORD_TUPLE(_(AddRecordSpread)) \ + IF_RECORD_TUPLE(_(FinishRecord)) \ + IF_RECORD_TUPLE(_(InitTuple)) \ + IF_RECORD_TUPLE(_(AddTupleElement)) \ + IF_RECORD_TUPLE(_(FinishTuple)) \ + // === !! WARNING WARNING WARNING !! === + // Do you really want to sacrifice performance by not implementing this + // operation in the optimizing compiler? + +class MIRGenerator; +class MIRGraph; +class WarpSnapshot; + +enum class CacheKind : uint8_t; + +// [SMDOC] Control Flow handling in WarpBuilder. +// +// WarpBuilder traverses the script's bytecode and compiles each instruction to +// corresponding MIR instructions. Handling control flow bytecode ops requires +// some special machinery: +// +// Forward branches +// ---------------- +// Most branches in the bytecode are forward branches to a JSOp::JumpTarget +// instruction that we have not inspected yet. We compile them in two phases: +// +// 1) When compiling the source instruction: the MBasicBlock is terminated +// with a control instruction that has a nullptr successor block. We also add +// a PendingEdge instance to the PendingEdges list for the target bytecode +// location. +// +// 2) When finally compiling the JSOp::JumpTarget: WarpBuilder::build_JumpTarget +// creates the target block and uses the list of PendingEdges to 'link' the +// blocks. +// +// Loops +// ----- +// Loops may be nested within other loops, so each WarpBuilder has a LoopState +// stack. This is used to link the backedge to the loop's header block. +// +// Unreachable/dead code +// --------------------- +// Some bytecode instructions never fall through to the next instruction, for +// example JSOp::Return, JSOp::Goto, or JSOp::Throw. Code after such +// instructions is guaranteed to be dead so WarpBuilder skips it until it gets +// to a jump target instruction with pending edges. +// +// Note: The frontend may generate unnecessary JSOp::JumpTarget instructions we +// can ignore when they have no incoming pending edges. +// +// Try-catch +// --------- +// WarpBuilder supports scripts with try-catch by only compiling the try-block +// and bailing out (to the Baseline Interpreter) from the exception handler +// whenever we need to execute the catch-block. +// +// Because we don't compile the catch-block and the code after the try-catch may +// only be reachable via the catch-block, Baseline's BytecodeAnalysis ensures +// Baseline does not attempt OSR into Warp at loops that are only reachable via +// catch/finally blocks. +// +// Finally-blocks are compiled by WarpBuilder, but when we have to enter a +// finally-block from the exception handler, we bail out to the Baseline +// Interpreter. + +// PendingEdge is used whenever a block is terminated with a forward branch in +// the bytecode. When we reach the jump target we use this information to link +// the block to the jump target's block. +class PendingEdge { + MBasicBlock* block_; + uint32_t successor_; + uint8_t numToPop_; + + public: + PendingEdge(MBasicBlock* block, uint32_t successor, uint32_t numToPop) + : block_(block), successor_(successor), numToPop_(numToPop) { + MOZ_ASSERT(numToPop_ == numToPop, "value must fit in field"); + } + + MBasicBlock* block() const { return block_; } + uint32_t successor() const { return successor_; } + uint8_t numToPop() const { return numToPop_; } +}; + +// PendingEdgesMap maps a bytecode instruction to a Vector of PendingEdges +// targeting it. We use InlineMap<> for this because most of the time there are +// only a few pending edges but there can be many when switch-statements are +// involved. +using PendingEdges = Vector<PendingEdge, 2, SystemAllocPolicy>; +using PendingEdgesMap = + InlineMap<jsbytecode*, PendingEdges, 8, PointerHasher<jsbytecode*>, + SystemAllocPolicy>; + +// LoopState stores information about a loop that's being compiled to MIR. +class LoopState { + MBasicBlock* header_ = nullptr; + + public: + explicit LoopState(MBasicBlock* header) : header_(header) {} + + MBasicBlock* header() const { return header_; } +}; +using LoopStateStack = Vector<LoopState, 4, JitAllocPolicy>; + +// Data that is shared across all WarpBuilders for a given compilation. +class MOZ_STACK_CLASS WarpCompilation { + // The total loop depth, including loops in the caller while + // compiling inlined functions. + uint32_t loopDepth_ = 0; + + // Loop phis for iterators that need to be kept alive. + PhiVector iterators_; + + public: + explicit WarpCompilation(TempAllocator& alloc) : iterators_(alloc) {} + + uint32_t loopDepth() const { return loopDepth_; } + void incLoopDepth() { loopDepth_++; } + void decLoopDepth() { + MOZ_ASSERT(loopDepth() > 0); + loopDepth_--; + } + + PhiVector* iterators() { return &iterators_; } +}; + +// WarpBuilder builds a MIR graph from WarpSnapshot. Unlike WarpOracle, +// WarpBuilder can run off-thread. +class MOZ_STACK_CLASS WarpBuilder : public WarpBuilderShared { + WarpCompilation* warpCompilation_; + MIRGraph& graph_; + const CompileInfo& info_; + const WarpScriptSnapshot* scriptSnapshot_; + JSScript* script_; + + // Pointer to a WarpOpSnapshot or nullptr if we reached the end of the list. + // Because bytecode is compiled from first to last instruction (and + // WarpOpSnapshot is sorted the same way), the iterator always moves forward. + const WarpOpSnapshot* opSnapshotIter_ = nullptr; + + // Note: loopStack_ is builder-specific. loopStack_.length is the + // depth relative to the current script. The overall loop depth is + // stored in the WarpCompilation. + LoopStateStack loopStack_; + PendingEdgesMap pendingEdges_; + + // These are only initialized when building an inlined script. + WarpBuilder* callerBuilder_ = nullptr; + MResumePoint* callerResumePoint_ = nullptr; + CallInfo* inlineCallInfo_ = nullptr; + + WarpCompilation* warpCompilation() const { return warpCompilation_; } + MIRGraph& graph() { return graph_; } + const CompileInfo& info() const { return info_; } + const WarpScriptSnapshot* scriptSnapshot() const { return scriptSnapshot_; } + + uint32_t loopDepth() const { return warpCompilation_->loopDepth(); } + void incLoopDepth() { warpCompilation_->incLoopDepth(); } + void decLoopDepth() { warpCompilation_->decLoopDepth(); } + PhiVector* iterators() { return warpCompilation_->iterators(); } + + WarpBuilder* callerBuilder() const { return callerBuilder_; } + MResumePoint* callerResumePoint() const { return callerResumePoint_; } + + BytecodeSite* newBytecodeSite(BytecodeLocation loc); + + const WarpOpSnapshot* getOpSnapshotImpl(BytecodeLocation loc, + WarpOpSnapshot::Kind kind); + + template <typename T> + const T* getOpSnapshot(BytecodeLocation loc) { + const WarpOpSnapshot* snapshot = getOpSnapshotImpl(loc, T::ThisKind); + return snapshot ? snapshot->as<T>() : nullptr; + } + + void initBlock(MBasicBlock* block); + [[nodiscard]] bool startNewEntryBlock(size_t stackDepth, + BytecodeLocation loc); + [[nodiscard]] bool startNewBlock(MBasicBlock* predecessor, + BytecodeLocation loc, size_t numToPop = 0); + [[nodiscard]] bool startNewLoopHeaderBlock(BytecodeLocation loopHead); + [[nodiscard]] bool startNewOsrPreHeaderBlock(BytecodeLocation loopHead); + + bool hasTerminatedBlock() const { return current == nullptr; } + void setTerminatedBlock() { current = nullptr; } + + [[nodiscard]] bool addPendingEdge(BytecodeLocation target, MBasicBlock* block, + uint32_t successor, uint32_t numToPop = 0); + [[nodiscard]] bool buildForwardGoto(BytecodeLocation target); + [[nodiscard]] bool buildBackedge(); + [[nodiscard]] bool buildTestBackedge(BytecodeLocation loc); + + [[nodiscard]] bool addIteratorLoopPhis(BytecodeLocation loopHead); + + [[nodiscard]] bool buildPrologue(); + [[nodiscard]] bool buildBody(); + + [[nodiscard]] bool buildInlinePrologue(); + + [[nodiscard]] bool buildIC(BytecodeLocation loc, CacheKind kind, + std::initializer_list<MDefinition*> inputs); + [[nodiscard]] bool buildBailoutForColdIC(BytecodeLocation loc, + CacheKind kind); + + [[nodiscard]] bool buildEnvironmentChain(); + MInstruction* buildNamedLambdaEnv(MDefinition* callee, MDefinition* env, + NamedLambdaObject* templateObj); + MInstruction* buildCallObject(MDefinition* callee, MDefinition* env, + CallObject* templateObj); + MInstruction* buildLoadSlot(MDefinition* obj, uint32_t numFixedSlots, + uint32_t slot); + + MConstant* globalLexicalEnvConstant(); + MDefinition* getCallee(); + + [[nodiscard]] bool buildUnaryOp(BytecodeLocation loc); + [[nodiscard]] bool buildBinaryOp(BytecodeLocation loc); + [[nodiscard]] bool buildCompareOp(BytecodeLocation loc); + [[nodiscard]] bool buildTestOp(BytecodeLocation loc); + [[nodiscard]] bool buildCallOp(BytecodeLocation loc); + + [[nodiscard]] bool buildInitPropGetterSetterOp(BytecodeLocation loc); + [[nodiscard]] bool buildInitElemGetterSetterOp(BytecodeLocation loc); + + [[nodiscard]] bool buildSuspend(BytecodeLocation loc, MDefinition* gen, + MDefinition* retVal); + + void buildCheckLexicalOp(BytecodeLocation loc); + + bool usesEnvironmentChain() const; + MDefinition* walkEnvironmentChain(uint32_t numHops); + + void buildCreateThis(CallInfo& callInfo); + + [[nodiscard]] bool transpileCall(BytecodeLocation loc, + const WarpCacheIR* cacheIRSnapshot, + CallInfo* callInfo); + + [[nodiscard]] bool buildInlinedCall(BytecodeLocation loc, + const WarpInlinedCall* snapshot, + CallInfo& callInfo); + + MDefinition* patchInlinedReturns(CompileInfo* calleeCompileInfo, + CallInfo& callInfo, MIRGraphReturns& exits, + MBasicBlock* returnBlock); + MDefinition* patchInlinedReturn(CompileInfo* calleeCompileInfo, + CallInfo& callInfo, MBasicBlock* exit, + MBasicBlock* returnBlock); + +#define BUILD_OP(OP, ...) [[nodiscard]] bool build_##OP(BytecodeLocation loc); + FOR_EACH_OPCODE(BUILD_OP) +#undef BUILD_OP + + public: + WarpBuilder(WarpSnapshot& snapshot, MIRGenerator& mirGen, + WarpCompilation* warpCompilation); + WarpBuilder(WarpBuilder* caller, WarpScriptSnapshot* snapshot, + CompileInfo& compileInfo, CallInfo* inlineCallInfo, + MResumePoint* callerResumePoint); + + [[nodiscard]] bool build(); + [[nodiscard]] bool buildInline(); + + CallInfo* inlineCallInfo() const { return inlineCallInfo_; } +}; + +} // namespace jit +} // namespace js + +#endif /* jit_WarpBuilder_h */ |