-// $Id$ -*-c++-*-
-//***************************************************************************
-// File:
-// InstrSelection.h
+//===- InstrSelection.cpp - Machine Independent Inst Selection Driver -----===//
//
-// Purpose:
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Machine-independent driver file for instruction selection. This file
+// constructs a forest of BURG instruction trees and then uses the
+// BURG-generated tree grammar (BURM) to find the optimal instruction sequences
+// for a given machine.
//
-// History:
-// 7/02/01 - Vikram Adve - Created
-//***************************************************************************
-
+//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/InstrSelection.h"
-#include "llvm/Method.h"
-#include "llvm/BasicBlock.h"
-#include "llvm/Type.h"
-#include "llvm/iMemory.h"
-#include "llvm/Instruction.h"
-#include "llvm/CodeGen/MachineInstr.h"
-#include "llvm/Support/CommandLine.h"
+#include "llvm/Function.h"
+#include "llvm/iPHINode.h"
+#include "llvm/iOther.h"
+#include "llvm/Pass.h"
+#include "llvm/CodeGen/InstrForest.h"
+#include "llvm/CodeGen/IntrinsicLowering.h"
+#include "llvm/CodeGen/MachineCodeForInstruction.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Support/CFG.h"
+#include "../SparcV9RegInfo.h"
+#include "Support/CommandLine.h"
+#include "Support/LeakDetector.h"
+#include <iostream>
-enum DebugLev {
- NoDebugInfo,
- DebugInstTrees,
- DebugBurgTrees,
-};
+namespace llvm {
+ std::vector<MachineInstr*>
+ FixConstantOperandsForInstr(Instruction *I, MachineInstr *MI,
+ TargetMachine &TM);
+}
-// Enable Debug Options to be specified on the command line
-cl::Enum<enum DebugLev> DebugLevel("debug_select", cl::NoFlags, // cl::Hidden
- "enable instruction selection debugging information",
- clEnumVal(NoDebugInfo , "disable debug output"),
- clEnumVal(DebugInstTrees, "print instruction trees"),
- clEnumVal(DebugBurgTrees, "print burg trees"), 0);
+namespace {
+ //===--------------------------------------------------------------------===//
+ // SelectDebugLevel - Allow command line control over debugging.
+ //
+ enum SelectDebugLevel_t {
+ Select_NoDebugInfo,
+ Select_PrintMachineCode,
+ Select_DebugInstTrees,
+ Select_DebugBurgTrees,
+ };
+
+ // Enable Debug Options to be specified on the command line
+ cl::opt<SelectDebugLevel_t>
+ SelectDebugLevel("dselect", cl::Hidden,
+ cl::desc("enable instruction selection debug information"),
+ cl::values(
+ clEnumValN(Select_NoDebugInfo, "n", "disable debug output"),
+ clEnumValN(Select_PrintMachineCode, "y", "print generated machine code"),
+ clEnumValN(Select_DebugInstTrees, "i",
+ "print debugging info for instruction selection"),
+ clEnumValN(Select_DebugBurgTrees, "b", "print burg trees"),
+ clEnumValEnd));
-//************************* Forward Declarations ***************************/
-static bool SelectInstructionsForTree(BasicTreeNode* treeRoot, int goalnt,
- TargetMachine &Target);
+ //===--------------------------------------------------------------------===//
+ // InstructionSelection Pass
+ //
+ // This is the actual pass object that drives the instruction selection
+ // process.
+ //
+ class InstructionSelection : public FunctionPass {
+ TargetMachine &Target;
+ void InsertCodeForPhis(Function &F);
+ void InsertPhiElimInstructions(BasicBlock *BB,
+ const std::vector<MachineInstr*>& CpVec);
+ void SelectInstructionsForTree(InstrTreeNode* treeRoot, int goalnt);
+ void PostprocessMachineCodeForTree(InstructionNode* instrNode,
+ int ruleForNode, short* nts);
+ public:
+ InstructionSelection(TargetMachine &TM) : Target(TM) {}
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ }
+
+ bool runOnFunction(Function &F);
+ virtual const char *getPassName() const { return "Instruction Selection"; }
+ };
+}
-//******************* Externally Visible Functions *************************/
+TmpInstruction::TmpInstruction(Value *s1, Value *s2, const std::string &name)
+ : Instruction(s1->getType(), Instruction::UserOp1, name)
+{
+ Operands.push_back(Use(s1, this)); // s1 must be non-null
+ if (s2)
+ Operands.push_back(Use(s2, this));
+ // TmpInstructions should not be garbage checked.
+ LeakDetector::removeGarbageObject(this);
+}
-//---------------------------------------------------------------------------
-// Entry point for instruction selection using BURG.
-// Returns true if instruction selection failed, false otherwise.
-//---------------------------------------------------------------------------
+TmpInstruction::TmpInstruction(MachineCodeForInstruction& mcfi,
+ Value *s1, Value *s2, const std::string &name)
+ : Instruction(s1->getType(), Instruction::UserOp1, name)
+{
+ mcfi.addTemp(this);
-bool SelectInstructionsForMethod(Method* method, TargetMachine &Target) {
- bool failed = false;
-
- InstrForest instrForest;
- instrForest.buildTreesForMethod(method);
-
- const hash_set<InstructionNode*> &treeRoots = instrForest.getRootSet();
+ Operands.push_back(Use(s1, this)); // s1 must be non-null
+ if (s2)
+ Operands.push_back(Use(s2, this));
+
+ // TmpInstructions should not be garbage checked.
+ LeakDetector::removeGarbageObject(this);
+}
+
+// Constructor that requires the type of the temporary to be specified.
+// Both S1 and S2 may be NULL.
+TmpInstruction::TmpInstruction(MachineCodeForInstruction& mcfi,
+ const Type *Ty, Value *s1, Value* s2,
+ const std::string &name)
+ : Instruction(Ty, Instruction::UserOp1, name)
+{
+ mcfi.addTemp(this);
+
+ if (s1)
+ Operands.push_back(Use(s1, this));
+ if (s2)
+ Operands.push_back(Use(s2, this));
+
+ // TmpInstructions should not be garbage checked.
+ LeakDetector::removeGarbageObject(this);
+}
+
+bool InstructionSelection::runOnFunction(Function &F) {
+ // First pass - Walk the function, lowering any calls to intrinsic functions
+ // which the instruction selector cannot handle.
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; )
+ if (CallInst *CI = dyn_cast<CallInst>(I++))
+ if (Function *F = CI->getCalledFunction())
+ switch (F->getIntrinsicID()) {
+ case Intrinsic::not_intrinsic:
+ case Intrinsic::vastart:
+ case Intrinsic::vacopy:
+ case Intrinsic::vaend:
+ // We directly implement these intrinsics. Note that this knowledge
+ // is incestuously entangled with the code in
+ // SparcInstrSelection.cpp and must be updated when it is updated.
+ // Since ALL of the code in this library is incestuously intertwined
+ // with it already and sparc specific, we will live with this.
+ break;
+ default:
+ // All other intrinsic calls we must lower.
+ Instruction *Before = CI->getPrev();
+ Target.getIntrinsicLowering().LowerIntrinsicCall(CI);
+ if (Before) { // Move iterator to instruction after call
+ I = Before; ++I;
+ } else {
+ I = BB->begin();
+ }
+ }
+
+ // Build the instruction trees to be given as inputs to BURG.
+ InstrForest instrForest(&F);
+ if (SelectDebugLevel >= Select_DebugInstTrees) {
+ std::cerr << "\n\n*** Input to instruction selection for function "
+ << F.getName() << "\n\n" << F
+ << "\n\n*** Instruction trees for function "
+ << F.getName() << "\n\n";
+ instrForest.dump();
+ }
- //
// Invoke BURG instruction selection for each tree
- //
- for (hash_set<InstructionNode*>::const_iterator
- treeRootIter = treeRoots.begin();
- treeRootIter != treeRoots.end();
- ++treeRootIter)
- {
- BasicTreeNode* basicNode = (*treeRootIter)->getBasicNode();
-
- // Invoke BURM to label each tree node with a state
- (void) burm_label(basicNode);
+ for (InstrForest::const_root_iterator RI = instrForest.roots_begin();
+ RI != instrForest.roots_end(); ++RI) {
+ InstructionNode* basicNode = *RI;
+ assert(basicNode->parent() == NULL && "A `root' node has a parent?");
- if (DebugLevel >= DebugBurgTrees)
- {
- printcover(basicNode, 1, 0);
- cerr << "\nCover cost == " << treecost(basicNode, 1, 0) << "\n\n";
- printMatches(basicNode);
- }
-
- // Then recursively walk the tree to select instructions
- if (SelectInstructionsForTree(basicNode, /*goalnt*/1, Target))
- {
- failed = true;
- break;
- }
+ // Invoke BURM to label each tree node with a state
+ burm_label(basicNode);
+ if (SelectDebugLevel >= Select_DebugBurgTrees) {
+ printcover(basicNode, 1, 0);
+ std::cerr << "\nCover cost == " << treecost(basicNode, 1, 0) <<"\n\n";
+ printMatches(basicNode);
}
-
- if (!failed)
- {
- if (DebugLevel >= DebugInstTrees)
- {
- cout << "\n\n*** Instruction trees for method "
- << (method->hasName()? method->getName() : "")
- << endl << endl;
- instrForest.dump();
- }
- if (DebugLevel > NoDebugInfo)
- PrintMachineInstructions(method);
- }
+ // Then recursively walk the tree to select instructions
+ SelectInstructionsForTree(basicNode, /*goalnt*/1);
+ }
- return false;
-}
+ // Create the MachineBasicBlocks and add all of the MachineInstrs
+ // defined in the MachineCodeForInstruction objects to the MachineBasicBlocks.
+ MachineFunction &MF = MachineFunction::get(&F);
+ std::map<const BasicBlock *, MachineBasicBlock *> MBBMap;
+ for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
+ MachineBasicBlock *MBB = new MachineBasicBlock(BI);
+ MF.getBasicBlockList().push_back(MBB);
+ MBBMap[BI] = MBB;
+ for (BasicBlock::iterator II = BI->begin(); II != BI->end(); ++II) {
+ MachineCodeForInstruction &mvec = MachineCodeForInstruction::get(II);
+ MBB->insert(MBB->end(), mvec.begin(), mvec.end());
+ }
+ }
-//---------------------------------------------------------------------------
-// Function: FoldGetElemChain
-//
-// Purpose:
-// Fold a chain of GetElementPtr instructions into an equivalent
-// (Pointer, IndexVector) pair. Returns the pointer Value, and
-// stores the resulting IndexVector in argument chainIdxVec.
-//---------------------------------------------------------------------------
+ // Initialize Machine-CFG for the function.
+ for (MachineFunction::iterator i = MF.begin (), e = MF.end (); i != e; ++i) {
+ MachineBasicBlock &MBB = *i;
+ const BasicBlock *BB = MBB.getBasicBlock ();
+ // for each successor S of BB, add MBBMap[S] as a successor of MBB.
+ for (succ_const_iterator si = succ_begin(BB), se = succ_end(BB); si != se; ++si) {
+ MachineBasicBlock *succMBB = MBBMap[*si];
+ assert (succMBB && "Can't find MachineBasicBlock for this successor");
+ MBB.addSuccessor (succMBB);
+ }
+ }
-Value*
-FoldGetElemChain(const InstructionNode* getElemInstrNode,
- vector<ConstPoolVal*>& chainIdxVec)
-{
- MemAccessInst* getElemInst = (MemAccessInst*)
- getElemInstrNode->getInstruction();
+ // Insert phi elimination code
+ InsertCodeForPhis(F);
- // Initialize return values from the incoming instruction
- Value* ptrVal = getElemInst->getPtrOperand();
- chainIdxVec = getElemInst->getIndexVec(); // copies index vector values
+ if (SelectDebugLevel >= Select_PrintMachineCode) {
+ std::cerr << "\n*** Machine instructions after INSTRUCTION SELECTION\n";
+ MachineFunction::get(&F).dump();
+ }
- // Now chase the chain of getElementInstr instructions, if any
- InstrTreeNode* ptrChild = getElemInstrNode->leftChild();
- while (ptrChild->getOpLabel() == Instruction::GetElementPtr ||
- ptrChild->getOpLabel() == GetElemPtrIdx)
- {
- // Child is a GetElemPtr instruction
- getElemInst = (MemAccessInst*)
- ((InstructionNode*) ptrChild)->getInstruction();
- const vector<ConstPoolVal*>& idxVec = getElemInst->getIndexVec();
-
- // Get the pointer value out of ptrChild and *prepend* its index vector
- ptrVal = getElemInst->getPtrOperand();
- chainIdxVec.insert(chainIdxVec.begin(), idxVec.begin(), idxVec.end());
-
- ptrChild = ptrChild->leftChild();
- }
-
- return ptrVal;
+ return true;
}
+/// InsertCodeForPhis - This method inserts Phi elimination code for
+/// all Phi nodes in the given function. After this method is called,
+/// the Phi nodes still exist in the LLVM code, but copies are added to the
+/// machine code.
+///
+void InstructionSelection::InsertCodeForPhis(Function &F) {
+ // Iterate over every Phi node PN in F:
+ MachineFunction &MF = MachineFunction::get(&F);
+ for (MachineFunction::iterator BB = MF.begin(); BB != MF.end(); ++BB) {
+ for (BasicBlock::const_iterator IIt = BB->getBasicBlock()->begin();
+ const PHINode *PN = dyn_cast<PHINode>(IIt); ++IIt) {
+ // Create a new temporary register to hold the result of the Phi copy.
+ // The leak detector shouldn't track these nodes. They are not garbage,
+ // even though their parent field is never filled in.
+ Value *PhiCpRes = new PHINode(PN->getType(), PN->getName() + ":PhiCp");
+ LeakDetector::removeGarbageObject(PhiCpRes);
-void PrintMachineInstructions(Method* method) {
- cout << "\n" << method->getReturnType()
- << " \"" << method->getName() << "\"" << endl;
-
- for (Method::const_iterator bbIter = method->begin();
- bbIter != method->end();
- ++bbIter)
- {
- BasicBlock* bb = *bbIter;
- cout << "\n"
- << (bb->hasName()? bb->getName() : "Label")
- << " (" << bb << ")" << ":"
- << endl;
-
- for (BasicBlock::const_iterator instrIter = bb->begin();
- instrIter != bb->end();
- ++instrIter)
- {
- Instruction *instr = *instrIter;
- const MachineCodeForVMInstr& minstrVec = instr->getMachineInstrVec();
- for (unsigned i=0, N=minstrVec.size(); i < N; i++)
- cout << "\t" << *minstrVec[i] << endl;
- }
- }
+ // For each of PN's incoming values, insert a copy in the corresponding
+ // predecessor block.
+ MachineCodeForInstruction &MCforPN = MachineCodeForInstruction::get (PN);
+ for (unsigned i = 0; i < PN->getNumIncomingValues(); ++i) {
+ std::vector<MachineInstr*> mvec, CpVec;
+ Target.getRegInfo()->cpValue2Value(PN->getIncomingValue(i),
+ PhiCpRes, mvec);
+ for (std::vector<MachineInstr*>::iterator MI=mvec.begin();
+ MI != mvec.end(); ++MI) {
+ std::vector<MachineInstr*> CpVec2 =
+ FixConstantOperandsForInstr(const_cast<PHINode*>(PN), *MI, Target);
+ CpVec2.push_back(*MI);
+ CpVec.insert(CpVec.end(), CpVec2.begin(), CpVec2.end());
+ }
+ // Insert the copy instructions into the predecessor BB.
+ InsertPhiElimInstructions(PN->getIncomingBlock(i), CpVec);
+ MCforPN.insert (MCforPN.end (), CpVec.begin (), CpVec.end ());
+ }
+ // Insert a copy instruction from PhiCpRes to PN.
+ std::vector<MachineInstr*> mvec;
+ Target.getRegInfo()->cpValue2Value(PhiCpRes, const_cast<PHINode*>(PN),
+ mvec);
+ BB->insert(BB->begin(), mvec.begin(), mvec.end());
+ MCforPN.insert (MCforPN.end (), mvec.begin (), mvec.end ());
+ } // for each Phi Instr in BB
+ } // for all BBs in function
}
-//*********************** Private Functions *****************************/
+/// InsertPhiElimInstructions - Inserts the instructions in CpVec into the
+/// MachineBasicBlock corresponding to BB, just before its terminator
+/// instruction. This is used by InsertCodeForPhis() to insert copies, above.
+///
+void
+InstructionSelection::InsertPhiElimInstructions(BasicBlock *BB,
+ const std::vector<MachineInstr*>& CpVec)
+{
+ Instruction *TermInst = (Instruction*)BB->getTerminator();
+ MachineCodeForInstruction &MC4Term = MachineCodeForInstruction::get(TermInst);
+ MachineInstr *FirstMIOfTerm = MC4Term.front();
+ assert (FirstMIOfTerm && "No Machine Instrs for terminator");
+
+ MachineBasicBlock *MBB = FirstMIOfTerm->getParent();
+ assert(MBB && "Machine BB for predecessor's terminator not found");
+ MachineBasicBlock::iterator MCIt = FirstMIOfTerm;
+ assert(MCIt != MBB->end() && "Start inst of terminator not found");
+
+ // insert the copy instructions just before the first machine instruction
+ // generated for the terminator
+ MBB->insert(MCIt, CpVec.begin(), CpVec.end());
+}
//---------------------------------------------------------------------------
// may be used by multiple instructions).
//---------------------------------------------------------------------------
-bool
-SelectInstructionsForTree(BasicTreeNode* treeRoot,
- int goalnt,
- TargetMachine &Target)
+void
+InstructionSelection::SelectInstructionsForTree(InstrTreeNode* treeRoot,
+ int goalnt)
{
- // Use a static vector to avoid allocating a new one per VM instruction
- static MachineInstr* minstrVec[MAX_INSTR_PER_VMINSTR];
-
// Get the rule that matches this node.
//
int ruleForNode = burm_rule(treeRoot->state, goalnt);
- if (ruleForNode == 0)
- {
- cerr << "Could not match instruction tree for instr selection" << endl;
- return true;
- }
+ if (ruleForNode == 0) {
+ std::cerr << "Could not match instruction tree for instr selection\n";
+ abort();
+ }
// Get this rule's non-terminals and the corresponding child nodes (if any)
//
short *nts = burm_nts[ruleForNode];
-
// First, select instructions for the current node and rule.
// (If this is a list node, not an instruction, then skip this step).
// This function is specific to the target architecture.
//
- if (treeRoot->opLabel != VRegListOp)
- {
- InstructionNode* instrNode = (InstructionNode*) MainTreeNode(treeRoot);
- assert(instrNode->getNodeType() == InstrTreeNode::NTInstructionNode);
+ if (treeRoot->opLabel != VRegListOp) {
+ std::vector<MachineInstr*> minstrVec;
- unsigned N = GetInstructionsByRule(instrNode, ruleForNode, nts, Target,
- minstrVec);
- assert(N <= MAX_INSTR_PER_VMINSTR);
- for (unsigned i=0; i < N; i++)
- {
- assert(minstrVec[i] != NULL);
- instrNode->getInstruction()->addMachineInstruction(minstrVec[i]);
- }
- }
+ InstructionNode* instrNode = (InstructionNode*)treeRoot;
+ assert(instrNode->getNodeType() == InstrTreeNode::NTInstructionNode);
+
+ GetInstructionsByRule(instrNode, ruleForNode, nts, Target, minstrVec);
+
+ MachineCodeForInstruction &mvec =
+ MachineCodeForInstruction::get(instrNode->getInstruction());
+ mvec.insert(mvec.end(), minstrVec.begin(), minstrVec.end());
+ }
// Then, recursively compile the child nodes, if any.
//
- if (nts[0])
- { // i.e., there is at least one kid
-
- BasicTreeNode* kids[2];
- int currentRule = ruleForNode;
+ if (nts[0]) {
+ // i.e., there is at least one kid
+ InstrTreeNode* kids[2];
+ int currentRule = ruleForNode;
+ burm_kids(treeRoot, currentRule, kids);
+
+ // First skip over any chain rules so that we don't visit
+ // the current node again.
+ //
+ while (ThisIsAChainRule(currentRule)) {
+ currentRule = burm_rule(treeRoot->state, nts[0]);
+ nts = burm_nts[currentRule];
burm_kids(treeRoot, currentRule, kids);
+ }
- // First skip over any chain rules so that we don't visit
- // the current node again.
- //
- while (ThisIsAChainRule(currentRule))
- {
- currentRule = burm_rule(treeRoot->state, nts[0]);
- nts = burm_nts[currentRule];
- burm_kids(treeRoot, currentRule, kids);
- }
-
- // Now we have the first non-chain rule so we have found
- // the actual child nodes. Recursively compile them.
- //
- for (int i = 0; nts[i]; i++)
- {
- assert(i < 2);
- InstrTreeNode::InstrTreeNodeType
- nodeType = MainTreeNode(kids[i])->getNodeType();
- if (nodeType == InstrTreeNode::NTVRegListNode ||
- nodeType == InstrTreeNode::NTInstructionNode)
- {
- if (SelectInstructionsForTree(kids[i], nts[i], Target))
- return true; // failure
- }
- }
+ // Now we have the first non-chain rule so we have found
+ // the actual child nodes. Recursively compile them.
+ //
+ for (unsigned i = 0; nts[i]; i++) {
+ assert(i < 2);
+ InstrTreeNode::InstrTreeNodeType nodeType = kids[i]->getNodeType();
+ if (nodeType == InstrTreeNode::NTVRegListNode ||
+ nodeType == InstrTreeNode::NTInstructionNode)
+ SelectInstructionsForTree(kids[i], nts[i]);
}
+ }
- return false; // success
+ // Finally, do any post-processing on this node after its children
+ // have been translated
+ //
+ if (treeRoot->opLabel != VRegListOp)
+ PostprocessMachineCodeForTree((InstructionNode*)treeRoot, ruleForNode, nts);
+}
+
+//---------------------------------------------------------------------------
+// Function PostprocessMachineCodeForTree
+//
+// Apply any final cleanups to machine code for the root of a subtree
+// after selection for all its children has been completed.
+//
+void
+InstructionSelection::PostprocessMachineCodeForTree(InstructionNode* instrNode,
+ int ruleForNode,
+ short* nts)
+{
+ // Fix up any constant operands in the machine instructions to either
+ // use an immediate field or to load the constant into a register
+ // Walk backwards and use direct indexes to allow insertion before current
+ //
+ Instruction* vmInstr = instrNode->getInstruction();
+ MachineCodeForInstruction &mvec = MachineCodeForInstruction::get(vmInstr);
+ for (unsigned i = mvec.size(); i != 0; --i) {
+ std::vector<MachineInstr*> loadConstVec =
+ FixConstantOperandsForInstr(vmInstr, mvec[i-1], Target);
+
+ mvec.insert(mvec.begin()+i-1, loadConstVec.begin(), loadConstVec.end());
+ }
}
+
+//===----------------------------------------------------------------------===//
+// createInstructionSelectionPass - Public entrypoint for instruction selection
+// and this file as a whole...
+//
+FunctionPass *llvm::createInstructionSelectionPass(TargetMachine &TM) {
+ return new InstructionSelection(TM);
+}