//===- DAGISelMatcherGen.cpp - Matcher generator --------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// #include "DAGISelMatcher.h" #include "CodeGenDAGPatterns.h" #include "Record.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/StringMap.h" using namespace llvm; namespace { class MatcherGen { const PatternToMatch &Pattern; const CodeGenDAGPatterns &CGP; /// PatWithNoTypes - This is a clone of Pattern.getSrcPattern() that starts /// out with all of the types removed. This allows us to insert type checks /// as we scan the tree. TreePatternNode *PatWithNoTypes; /// VariableMap - A map from variable names ('$dst') to the recorded operand /// number that they were captured as. These are biased by 1 to make /// insertion easier. StringMap VariableMap; unsigned NextRecordedOperandNo; /// InputChains - This maintains the position in the recorded nodes array of /// all of the recorded input chains. SmallVector InputChains; /// Matcher - This is the top level of the generated matcher, the result. MatcherNode *Matcher; /// CurPredicate - As we emit matcher nodes, this points to the latest check /// which should have future checks stuck into its child position. MatcherNode *CurPredicate; public: MatcherGen(const PatternToMatch &pattern, const CodeGenDAGPatterns &cgp); ~MatcherGen() { delete PatWithNoTypes; } void EmitMatcherCode(); MatcherNode *GetMatcher() const { return Matcher; } MatcherNode *GetCurPredicate() const { return CurPredicate; } private: void AddMatcherNode(MatcherNode *NewNode); void InferPossibleTypes(); void EmitMatchCode(const TreePatternNode *N, TreePatternNode *NodeNoTypes); void EmitLeafMatchCode(const TreePatternNode *N); void EmitOperatorMatchCode(const TreePatternNode *N, TreePatternNode *NodeNoTypes); }; } // end anon namespace. MatcherGen::MatcherGen(const PatternToMatch &pattern, const CodeGenDAGPatterns &cgp) : Pattern(pattern), CGP(cgp), NextRecordedOperandNo(0), Matcher(0), CurPredicate(0) { // We need to produce the matcher tree for the patterns source pattern. To do // this we need to match the structure as well as the types. To do the type // matching, we want to figure out the fewest number of type checks we need to // emit. For example, if there is only one integer type supported by a // target, there should be no type comparisons at all for integer patterns! // // To figure out the fewest number of type checks needed, clone the pattern, // remove the types, then perform type inference on the pattern as a whole. // If there are unresolved types, emit an explicit check for those types, // apply the type to the tree, then rerun type inference. Iterate until all // types are resolved. // PatWithNoTypes = Pattern.getSrcPattern()->clone(); PatWithNoTypes->RemoveAllTypes(); // If there are types that are manifestly known, infer them. InferPossibleTypes(); } /// InferPossibleTypes - As we emit the pattern, we end up generating type /// checks and applying them to the 'PatWithNoTypes' tree. As we do this, we /// want to propagate implied types as far throughout the tree as possible so /// that we avoid doing redundant type checks. This does the type propagation. void MatcherGen::InferPossibleTypes() { // TP - Get *SOME* tree pattern, we don't care which. It is only used for // diagnostics, which we know are impossible at this point. TreePattern &TP = *CGP.pf_begin()->second; try { bool MadeChange = true; while (MadeChange) MadeChange = PatWithNoTypes->ApplyTypeConstraints(TP, true/*Ignore reg constraints*/); } catch (...) { errs() << "Type constraint application shouldn't fail!"; abort(); } } /// AddMatcherNode - Add a matcher node to the current graph we're building. void MatcherGen::AddMatcherNode(MatcherNode *NewNode) { if (CurPredicate != 0) CurPredicate->setChild(NewNode); else Matcher = NewNode; CurPredicate = NewNode; } /// EmitLeafMatchCode - Generate matching code for leaf nodes. void MatcherGen::EmitLeafMatchCode(const TreePatternNode *N) { assert(N->isLeaf() && "Not a leaf?"); // Direct match against an integer constant. if (IntInit *II = dynamic_cast(N->getLeafValue())) return AddMatcherNode(new CheckIntegerMatcherNode(II->getValue())); DefInit *DI = dynamic_cast(N->getLeafValue()); if (DI == 0) { errs() << "Unknown leaf kind: " << *DI << "\n"; abort(); } Record *LeafRec = DI->getDef(); if (// Handle register references. Nothing to do here, they always match. LeafRec->isSubClassOf("RegisterClass") || LeafRec->isSubClassOf("PointerLikeRegClass") || LeafRec->isSubClassOf("Register") || // Place holder for SRCVALUE nodes. Nothing to do here. LeafRec->getName() == "srcvalue") return; if (LeafRec->isSubClassOf("ValueType")) return AddMatcherNode(new CheckValueTypeMatcherNode(LeafRec->getName())); if (LeafRec->isSubClassOf("CondCode")) return AddMatcherNode(new CheckCondCodeMatcherNode(LeafRec->getName())); if (LeafRec->isSubClassOf("ComplexPattern")) { // We can't model ComplexPattern uses that don't have their name taken yet. // The OPC_CheckComplexPattern operation implicitly records the results. if (N->getName().empty()) { errs() << "We expect complex pattern uses to have names: " << *N << "\n"; exit(1); } // Handle complex pattern. const ComplexPattern &CP = CGP.getComplexPattern(LeafRec); AddMatcherNode(new CheckComplexPatMatcherNode(CP)); // If the complex pattern has a chain, then we need to keep track of the // fact that we just recorded a chain input. The chain input will be // matched as the last operand of the predicate if it was successful. if (CP.hasProperty(SDNPHasChain)) { // It is the last operand recorded. assert(NextRecordedOperandNo > 1 && "Should have recorded input/result chains at least!"); InputChains.push_back(NextRecordedOperandNo-1); // IF we need to check chains, do so, see comment for // "NodeHasProperty(SDNPHasChain" below. if (InputChains.size() > 1) { // FIXME: This is broken, we should eliminate this nonsense completely, // but we want to produce the same selections that the old matcher does // for now. unsigned PrevOp = InputChains[InputChains.size()-2]; AddMatcherNode(new CheckChainCompatibleMatcherNode(PrevOp)); } } return; } errs() << "Unknown leaf kind: " << *N << "\n"; abort(); } void MatcherGen::EmitOperatorMatchCode(const TreePatternNode *N, TreePatternNode *NodeNoTypes) { assert(!N->isLeaf() && "Not an operator?"); const SDNodeInfo &CInfo = CGP.getSDNodeInfo(N->getOperator()); // If this is an 'and R, 1234' where the operation is AND/OR and the RHS is // a constant without a predicate fn that has more that one bit set, handle // this as a special case. This is usually for targets that have special // handling of certain large constants (e.g. alpha with it's 8/16/32-bit // handling stuff). Using these instructions is often far more efficient // than materializing the constant. Unfortunately, both the instcombiner // and the dag combiner can often infer that bits are dead, and thus drop // them from the mask in the dag. For example, it might turn 'AND X, 255' // into 'AND X, 254' if it knows the low bit is set. Emit code that checks // to handle this. if ((N->getOperator()->getName() == "and" || N->getOperator()->getName() == "or") && N->getChild(1)->isLeaf() && N->getChild(1)->getPredicateFns().empty()) { if (IntInit *II = dynamic_cast(N->getChild(1)->getLeafValue())) { if (!isPowerOf2_32(II->getValue())) { // Don't bother with single bits. if (N->getOperator()->getName() == "and") AddMatcherNode(new CheckAndImmMatcherNode(II->getValue())); else AddMatcherNode(new CheckOrImmMatcherNode(II->getValue())); // Match the LHS of the AND as appropriate. AddMatcherNode(new MoveChildMatcherNode(0)); EmitMatchCode(N->getChild(0), NodeNoTypes->getChild(0)); AddMatcherNode(new MoveParentMatcherNode()); return; } } } // Check that the current opcode lines up. AddMatcherNode(new CheckOpcodeMatcherNode(CInfo.getEnumName())); // If this node has a chain, then the chain is operand #0 is the SDNode, and // the child numbers of the node are all offset by one. unsigned OpNo = 0; if (N->NodeHasProperty(SDNPHasChain, CGP)) { // Record the input chain, which is always input #0 of the SDNode. AddMatcherNode(new MoveChildMatcherNode(0)); AddMatcherNode(new RecordMatcherNode("'" + N->getOperator()->getName() + "' input chain")); // Remember all of the input chains our pattern will match. InputChains.push_back(NextRecordedOperandNo); ++NextRecordedOperandNo; AddMatcherNode(new MoveParentMatcherNode()); // If this is the second (e.g. indbr(load) or store(add(load))) or third // input chain (e.g. (store (add (load, load))) from msp430) we need to make // sure that folding the chain won't induce cycles in the DAG. This could // happen if there were an intermediate node between the indbr and load, for // example. if (InputChains.size() > 1) { // FIXME: This is broken, we should eliminate this nonsense completely, // but we want to produce the same selections that the old matcher does // for now. unsigned PrevOp = InputChains[InputChains.size()-2]; AddMatcherNode(new CheckChainCompatibleMatcherNode(PrevOp)); } // Don't look at the input chain when matching the tree pattern to the // SDNode. OpNo = 1; // If this node is not the root and the subtree underneath it produces a // chain, then the result of matching the node is also produce a chain. // Beyond that, this means that we're also folding (at least) the root node // into the node that produce the chain (for example, matching // "(add reg, (load ptr))" as a add_with_memory on X86). This is // problematic, if the 'reg' node also uses the load (say, its chain). // Graphically: // // [LD] // ^ ^ // | \ DAG's like cheese. // / | // / [YY] // | ^ // [XX]--/ // // It would be invalid to fold XX and LD. In this case, folding the two // nodes together would induce a cycle in the DAG, making it a 'cyclic DAG' // To prevent this, we emit a dynamic check for legality before allowing // this to be folded. // const TreePatternNode *Root = Pattern.getSrcPattern(); if (N != Root) { // Not the root of the pattern. // If there is a node between the root and this node, then we definitely // need to emit the check. bool NeedCheck = !Root->hasChild(N); // If it *is* an immediate child of the root, we can still need a check if // the root SDNode has multiple inputs. For us, this means that it is an // intrinsic, has multiple operands, or has other inputs like chain or // flag). if (!NeedCheck) { const SDNodeInfo &PInfo = CGP.getSDNodeInfo(Root->getOperator()); NeedCheck = Root->getOperator() == CGP.get_intrinsic_void_sdnode() || Root->getOperator() == CGP.get_intrinsic_w_chain_sdnode() || Root->getOperator() == CGP.get_intrinsic_wo_chain_sdnode() || PInfo.getNumOperands() > 1 || PInfo.hasProperty(SDNPHasChain) || PInfo.hasProperty(SDNPInFlag) || PInfo.hasProperty(SDNPOptInFlag); } if (NeedCheck) AddMatcherNode(new CheckFoldableChainNodeMatcherNode()); } } for (unsigned i = 0, e = N->getNumChildren(); i != e; ++i, ++OpNo) { // Get the code suitable for matching this child. Move to the child, check // it then move back to the parent. AddMatcherNode(new MoveChildMatcherNode(OpNo)); EmitMatchCode(N->getChild(i), NodeNoTypes->getChild(i)); AddMatcherNode(new MoveParentMatcherNode()); } } void MatcherGen::EmitMatchCode(const TreePatternNode *N, TreePatternNode *NodeNoTypes) { // If N and NodeNoTypes don't agree on a type, then this is a case where we // need to do a type check. Emit the check, apply the tyep to NodeNoTypes and // reinfer any correlated types. if (NodeNoTypes->getExtTypes() != N->getExtTypes()) { AddMatcherNode(new CheckTypeMatcherNode(N->getTypeNum(0))); NodeNoTypes->setTypes(N->getExtTypes()); InferPossibleTypes(); } // If this node has a name associated with it, capture it in VariableMap. If // we already saw this in the pattern, emit code to verify dagness. if (!N->getName().empty()) { unsigned &VarMapEntry = VariableMap[N->getName()]; if (VarMapEntry == 0) { VarMapEntry = NextRecordedOperandNo+1; unsigned NumRecorded; // If this is a complex pattern, the match operation for it will // implicitly record all of the outputs of it (which may be more than // one). if (const ComplexPattern *AM = N->getComplexPatternInfo(CGP)) { // Record the right number of operands. NumRecorded = AM->getNumOperands()-1; if (AM->hasProperty(SDNPHasChain)) NumRecorded += 2; // Input and output chains. } else { // If it is a normal named node, we must emit a 'Record' opcode. AddMatcherNode(new RecordMatcherNode("$" + N->getName())); NumRecorded = 1; } NextRecordedOperandNo += NumRecorded; } else { // If we get here, this is a second reference to a specific name. Since // we already have checked that the first reference is valid, we don't // have to recursively match it, just check that it's the same as the // previously named thing. AddMatcherNode(new CheckSameMatcherNode(VarMapEntry-1)); return; } } // If there are node predicates for this node, generate their checks. for (unsigned i = 0, e = N->getPredicateFns().size(); i != e; ++i) AddMatcherNode(new CheckPredicateMatcherNode(N->getPredicateFns()[i])); if (N->isLeaf()) EmitLeafMatchCode(N); else EmitOperatorMatchCode(N, NodeNoTypes); } void MatcherGen::EmitMatcherCode() { // If the pattern has a predicate on it (e.g. only enabled when a subtarget // feature is around, do the check). if (!Pattern.getPredicateCheck().empty()) AddMatcherNode(new CheckPatternPredicateMatcherNode(Pattern.getPredicateCheck())); // Emit the matcher for the pattern structure and types. EmitMatchCode(Pattern.getSrcPattern(), PatWithNoTypes); } MatcherNode *llvm::ConvertPatternToMatcher(const PatternToMatch &Pattern, const CodeGenDAGPatterns &CGP) { MatcherGen Gen(Pattern, CGP); // Generate the code for the matcher. Gen.EmitMatcherCode(); // If the match succeeds, then we generate Pattern. EmitNodeMatcherNode *Result = new EmitNodeMatcherNode(Pattern); // Link it into the pattern. if (MatcherNode *Pred = Gen.GetCurPredicate()) { Pred->setChild(Result); return Gen.GetMatcher(); } // Unconditional match. return Result; }