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to maintain a list of types (one for each result of the node) instead of a single type. There are liberal hacks added to emulate the old behavior in various situations, but they can start disolving now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98999 91177308-0d34-0410-b5e6-96231b3b80d8
234 lines
8.5 KiB
C++
234 lines
8.5 KiB
C++
//===- DAGISelEmitter.cpp - Generate an instruction selector --------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This tablegen backend emits a DAG instruction selector.
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//
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//===----------------------------------------------------------------------===//
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#include "DAGISelEmitter.h"
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#include "DAGISelMatcher.h"
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#include "Record.h"
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#include "llvm/Support/Debug.h"
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// DAGISelEmitter Helper methods
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//
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/// getPatternSize - Return the 'size' of this pattern. We want to match large
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/// patterns before small ones. This is used to determine the size of a
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/// pattern.
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static unsigned getPatternSize(TreePatternNode *P, CodeGenDAGPatterns &CGP) {
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unsigned Size = 3; // The node itself.
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// If the root node is a ConstantSDNode, increases its size.
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// e.g. (set R32:$dst, 0).
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if (P->isLeaf() && dynamic_cast<IntInit*>(P->getLeafValue()))
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Size += 2;
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// FIXME: This is a hack to statically increase the priority of patterns
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// which maps a sub-dag to a complex pattern. e.g. favors LEA over ADD.
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// Later we can allow complexity / cost for each pattern to be (optionally)
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// specified. To get best possible pattern match we'll need to dynamically
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// calculate the complexity of all patterns a dag can potentially map to.
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const ComplexPattern *AM = P->getComplexPatternInfo(CGP);
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if (AM)
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Size += AM->getNumOperands() * 3;
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// If this node has some predicate function that must match, it adds to the
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// complexity of this node.
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if (!P->getPredicateFns().empty())
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++Size;
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// Count children in the count if they are also nodes.
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for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i) {
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TreePatternNode *Child = P->getChild(i);
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if (!Child->isLeaf() && Child->getNumTypes() &&
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Child->getType(0) != MVT::Other)
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Size += getPatternSize(Child, CGP);
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else if (Child->isLeaf()) {
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if (dynamic_cast<IntInit*>(Child->getLeafValue()))
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Size += 5; // Matches a ConstantSDNode (+3) and a specific value (+2).
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else if (Child->getComplexPatternInfo(CGP))
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Size += getPatternSize(Child, CGP);
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else if (!Child->getPredicateFns().empty())
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++Size;
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}
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}
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return Size;
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}
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/// getResultPatternCost - Compute the number of instructions for this pattern.
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/// This is a temporary hack. We should really include the instruction
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/// latencies in this calculation.
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static unsigned getResultPatternCost(TreePatternNode *P,
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CodeGenDAGPatterns &CGP) {
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if (P->isLeaf()) return 0;
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unsigned Cost = 0;
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Record *Op = P->getOperator();
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if (Op->isSubClassOf("Instruction")) {
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Cost++;
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CodeGenInstruction &II = CGP.getTargetInfo().getInstruction(Op);
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if (II.usesCustomInserter)
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Cost += 10;
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}
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for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i)
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Cost += getResultPatternCost(P->getChild(i), CGP);
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return Cost;
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}
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/// getResultPatternCodeSize - Compute the code size of instructions for this
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/// pattern.
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static unsigned getResultPatternSize(TreePatternNode *P,
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CodeGenDAGPatterns &CGP) {
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if (P->isLeaf()) return 0;
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unsigned Cost = 0;
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Record *Op = P->getOperator();
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if (Op->isSubClassOf("Instruction")) {
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Cost += Op->getValueAsInt("CodeSize");
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}
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for (unsigned i = 0, e = P->getNumChildren(); i != e; ++i)
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Cost += getResultPatternSize(P->getChild(i), CGP);
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return Cost;
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}
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//===----------------------------------------------------------------------===//
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// Predicate emitter implementation.
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//
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void DAGISelEmitter::EmitPredicateFunctions(raw_ostream &OS) {
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OS << "\n// Predicate functions.\n";
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// Walk the pattern fragments, adding them to a map, which sorts them by
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// name.
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typedef std::map<std::string, std::pair<Record*, TreePattern*> > PFsByNameTy;
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PFsByNameTy PFsByName;
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for (CodeGenDAGPatterns::pf_iterator I = CGP.pf_begin(), E = CGP.pf_end();
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I != E; ++I)
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PFsByName.insert(std::make_pair(I->first->getName(), *I));
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for (PFsByNameTy::iterator I = PFsByName.begin(), E = PFsByName.end();
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I != E; ++I) {
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Record *PatFragRecord = I->second.first;// Record that derives from PatFrag.
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TreePattern *P = I->second.second;
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// If there is a code init for this fragment, emit the predicate code.
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std::string Code = PatFragRecord->getValueAsCode("Predicate");
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if (Code.empty()) continue;
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if (P->getOnlyTree()->isLeaf())
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OS << "inline bool Predicate_" << PatFragRecord->getName()
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<< "(SDNode *N) const {\n";
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else {
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std::string ClassName =
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CGP.getSDNodeInfo(P->getOnlyTree()->getOperator()).getSDClassName();
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const char *C2 = ClassName == "SDNode" ? "N" : "inN";
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OS << "inline bool Predicate_" << PatFragRecord->getName()
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<< "(SDNode *" << C2 << ") const {\n";
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if (ClassName != "SDNode")
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OS << " " << ClassName << " *N = cast<" << ClassName << ">(inN);\n";
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}
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OS << Code << "\n}\n";
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}
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OS << "\n\n";
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}
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namespace {
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// PatternSortingPredicate - return true if we prefer to match LHS before RHS.
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// In particular, we want to match maximal patterns first and lowest cost within
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// a particular complexity first.
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struct PatternSortingPredicate {
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PatternSortingPredicate(CodeGenDAGPatterns &cgp) : CGP(cgp) {}
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CodeGenDAGPatterns &CGP;
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bool operator()(const PatternToMatch *LHS,
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const PatternToMatch *RHS) {
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unsigned LHSSize = getPatternSize(LHS->getSrcPattern(), CGP);
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unsigned RHSSize = getPatternSize(RHS->getSrcPattern(), CGP);
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LHSSize += LHS->getAddedComplexity();
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RHSSize += RHS->getAddedComplexity();
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if (LHSSize > RHSSize) return true; // LHS -> bigger -> less cost
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if (LHSSize < RHSSize) return false;
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// If the patterns have equal complexity, compare generated instruction cost
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unsigned LHSCost = getResultPatternCost(LHS->getDstPattern(), CGP);
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unsigned RHSCost = getResultPatternCost(RHS->getDstPattern(), CGP);
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if (LHSCost < RHSCost) return true;
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if (LHSCost > RHSCost) return false;
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unsigned LHSPatSize = getResultPatternSize(LHS->getDstPattern(), CGP);
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unsigned RHSPatSize = getResultPatternSize(RHS->getDstPattern(), CGP);
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if (LHSPatSize < RHSPatSize) return true;
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if (LHSPatSize > RHSPatSize) return false;
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// Sort based on the UID of the pattern, giving us a deterministic ordering.
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assert(LHS == RHS || LHS->ID != RHS->ID);
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return LHS->ID < RHS->ID;
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}
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};
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}
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void DAGISelEmitter::run(raw_ostream &OS) {
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EmitSourceFileHeader("DAG Instruction Selector for the " +
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CGP.getTargetInfo().getName() + " target", OS);
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OS << "// *** NOTE: This file is #included into the middle of the target\n"
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<< "// *** instruction selector class. These functions are really "
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<< "methods.\n\n";
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DEBUG(errs() << "\n\nALL PATTERNS TO MATCH:\n\n";
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for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(),
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E = CGP.ptm_end(); I != E; ++I) {
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errs() << "PATTERN: "; I->getSrcPattern()->dump();
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errs() << "\nRESULT: "; I->getDstPattern()->dump();
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errs() << "\n";
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});
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// FIXME: These are being used by hand written code, gross.
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EmitPredicateFunctions(OS);
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// Add all the patterns to a temporary list so we can sort them.
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std::vector<const PatternToMatch*> Patterns;
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for (CodeGenDAGPatterns::ptm_iterator I = CGP.ptm_begin(), E = CGP.ptm_end();
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I != E; ++I)
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Patterns.push_back(&*I);
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// We want to process the matches in order of minimal cost. Sort the patterns
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// so the least cost one is at the start.
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std::stable_sort(Patterns.begin(), Patterns.end(),
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PatternSortingPredicate(CGP));
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// Convert each variant of each pattern into a Matcher.
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std::vector<Matcher*> PatternMatchers;
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for (unsigned i = 0, e = Patterns.size(); i != e; ++i) {
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for (unsigned Variant = 0; ; ++Variant) {
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if (Matcher *M = ConvertPatternToMatcher(*Patterns[i], Variant, CGP))
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PatternMatchers.push_back(M);
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else
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break;
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}
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}
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Matcher *TheMatcher = new ScopeMatcher(&PatternMatchers[0],
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PatternMatchers.size());
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TheMatcher = OptimizeMatcher(TheMatcher, CGP);
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//Matcher->dump();
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EmitMatcherTable(TheMatcher, CGP, OS);
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delete TheMatcher;
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}
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