//===- DAGISelEmitter.cpp - Generate an instruction selector --------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This tablegen backend emits a DAG instruction selector. // //===----------------------------------------------------------------------===// #include "DAGISelEmitter.h" #include "DAGISelMatcher.h" #include "Record.h" #include "llvm/Support/Debug.h" using namespace llvm; //===----------------------------------------------------------------------===// // DAGISelEmitter Helper methods // /// getResultPatternCost - Compute the number of instructions for this pattern. /// This is a temporary hack. We should really include the instruction /// latencies in this calculation. static unsigned getResultPatternCost(TreePatternNode *P, CodeGenDAGPatterns &CGP) { if (P->isLeaf()) return 0; unsigned Cost = 0; Record *Op = P->getOperator(); if (Op->isSubClassOf("Instruction")) { Cost++; CodeGenInstruction &II = CGP.getTargetInfo().getInstruction(Op); if (II.usesCustomInserter) Cost += 10; } for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i) Cost += getResultPatternCost(P->getChild(i), CGP); return Cost; } /// getResultPatternCodeSize - Compute the code size of instructions for this /// pattern. static unsigned getResultPatternSize(TreePatternNode *P, CodeGenDAGPatterns &CGP) { if (P->isLeaf()) return 0; unsigned Cost = 0; Record *Op = P->getOperator(); if (Op->isSubClassOf("Instruction")) { Cost += Op->getValueAsInt("CodeSize"); } for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i) Cost += getResultPatternSize(P->getChild(i), CGP); return Cost; } namespace { // PatternSortingPredicate - return true if we prefer to match LHS before RHS. // In particular, we want to match maximal patterns first and lowest cost within // a particular complexity first. struct PatternSortingPredicate { PatternSortingPredicate(CodeGenDAGPatterns &cgp) : CGP(cgp) {} CodeGenDAGPatterns &CGP; bool operator()(const PatternToMatch *LHS, const PatternToMatch *RHS) { const TreePatternNode *LHSSrc = LHS->getSrcPattern(); const TreePatternNode *RHSSrc = RHS->getSrcPattern(); if (LHSSrc->getNumTypes() != 0 && RHSSrc->getNumTypes() != 0 && LHSSrc->getType(0) != RHSSrc->getType(0)) { MVT::SimpleValueType V1 = LHSSrc->getType(0), V2 = RHSSrc->getType(0); if (MVT(V1).isVector() != MVT(V2).isVector()) return MVT(V2).isVector(); if (MVT(V1).isFloatingPoint() != MVT(V2).isFloatingPoint()) return MVT(V2).isFloatingPoint(); } // Otherwise, if the patterns might both match, sort based on complexity, // which means that we prefer to match patterns that cover more nodes in the // input over nodes that cover fewer. unsigned LHSSize = LHS->getPatternComplexity(CGP); unsigned RHSSize = RHS->getPatternComplexity(CGP); if (LHSSize > RHSSize) return true; // LHS -> bigger -> less cost if (LHSSize < RHSSize) return false; // If the patterns have equal complexity, compare generated instruction cost unsigned LHSCost = getResultPatternCost(LHS->getDstPattern(), CGP); unsigned RHSCost = getResultPatternCost(RHS->getDstPattern(), CGP); if (LHSCost < RHSCost) return true; if (LHSCost > RHSCost) return false; unsigned LHSPatSize = getResultPatternSize(LHS->getDstPattern(), CGP); unsigned RHSPatSize = getResultPatternSize(RHS->getDstPattern(), CGP); if (LHSPatSize < RHSPatSize) return true; if (LHSPatSize > RHSPatSize) return false; // Sort based on the UID of the pattern, giving us a deterministic ordering // if all other sorting conditions fail. assert(LHS == RHS || LHS->ID != RHS->ID); return LHS->ID < RHS->ID; } }; } void DAGISelEmitter::run(raw_ostream &OS) { EmitSourceFileHeader("DAG Instruction Selector for the " + CGP.getTargetInfo().getName() + " target", OS); OS << "// *** NOTE: This file is #included into the middle of the target\n" << "// *** instruction selector class. These functions are really " << "methods.\n\n"; DEBUG(errs() << "\n\nALL PATTERNS TO MATCH:\n\n"; for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(), E = CGP.ptm_end(); I != E; ++I) { errs() << "PATTERN: "; I->getSrcPattern()->dump(); errs() << "\nRESULT: "; I->getDstPattern()->dump(); errs() << "\n"; }); // Add all the patterns to a temporary list so we can sort them. std::vector Patterns; for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(), E = CGP.ptm_end(); I != E; ++I) Patterns.push_back(&*I); // We want to process the matches in order of minimal cost. Sort the patterns // so the least cost one is at the start. std::sort(Patterns.begin(), Patterns.end(), PatternSortingPredicate(CGP)); // Convert each variant of each pattern into a Matcher. std::vector PatternMatchers; for (unsigned i = 0, e = Patterns.size(); i != e; ++i) { for (unsigned Variant = 0; ; ++Variant) { if (Matcher *M = ConvertPatternToMatcher(*Patterns[i], Variant, CGP)) PatternMatchers.push_back(M); else break; } } Matcher *TheMatcher = new ScopeMatcher(&PatternMatchers[0], PatternMatchers.size()); CodeGenTarget Target(Records); const std::vector &Registers = Target.getRegisters(); bool useEmitRegister2 = Registers.size() > 255; TheMatcher = OptimizeMatcher(TheMatcher, CGP); //Matcher->dump(); EmitMatcherTable(TheMatcher, CGP, useEmitRegister2, OS); delete TheMatcher; }