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https://github.com/c64scene-ar/llvm-6502.git
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0b79a7727d
isSafeToSpeculativelyExecute. The new method is a bit closer to what the callers actually care about in that it rejects more things callers don't want. It also adds more precise handling for integer division, and unifies code for analyzing the legality of a speculative load. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76150 91177308-0d34-0410-b5e6-96231b3b80d8
423 lines
14 KiB
C++
423 lines
14 KiB
C++
//===-- Instruction.cpp - Implement the Instruction class -----------------===//
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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 file implements the Instruction class for the VMCore library.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Type.h"
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#include "llvm/Instructions.h"
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#include "llvm/Function.h"
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#include "llvm/Constants.h"
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#include "llvm/GlobalVariable.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Support/LeakDetector.h"
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using namespace llvm;
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Instruction::Instruction(const Type *ty, unsigned it, Use *Ops, unsigned NumOps,
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Instruction *InsertBefore)
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: User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
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// Make sure that we get added to a basicblock
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LeakDetector::addGarbageObject(this);
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// If requested, insert this instruction into a basic block...
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if (InsertBefore) {
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assert(InsertBefore->getParent() &&
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"Instruction to insert before is not in a basic block!");
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InsertBefore->getParent()->getInstList().insert(InsertBefore, this);
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}
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}
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Instruction::Instruction(const Type *ty, unsigned it, Use *Ops, unsigned NumOps,
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BasicBlock *InsertAtEnd)
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: User(ty, Value::InstructionVal + it, Ops, NumOps), Parent(0) {
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// Make sure that we get added to a basicblock
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LeakDetector::addGarbageObject(this);
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// append this instruction into the basic block
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assert(InsertAtEnd && "Basic block to append to may not be NULL!");
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InsertAtEnd->getInstList().push_back(this);
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}
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// Out of line virtual method, so the vtable, etc has a home.
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Instruction::~Instruction() {
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assert(Parent == 0 && "Instruction still linked in the program!");
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}
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void Instruction::setParent(BasicBlock *P) {
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if (getParent()) {
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if (!P) LeakDetector::addGarbageObject(this);
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} else {
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if (P) LeakDetector::removeGarbageObject(this);
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}
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Parent = P;
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}
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void Instruction::removeFromParent() {
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getParent()->getInstList().remove(this);
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}
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void Instruction::eraseFromParent() {
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getParent()->getInstList().erase(this);
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}
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/// insertBefore - Insert an unlinked instructions into a basic block
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/// immediately before the specified instruction.
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void Instruction::insertBefore(Instruction *InsertPos) {
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InsertPos->getParent()->getInstList().insert(InsertPos, this);
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}
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/// insertAfter - Insert an unlinked instructions into a basic block
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/// immediately after the specified instruction.
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void Instruction::insertAfter(Instruction *InsertPos) {
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InsertPos->getParent()->getInstList().insertAfter(InsertPos, this);
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}
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/// moveBefore - Unlink this instruction from its current basic block and
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/// insert it into the basic block that MovePos lives in, right before
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/// MovePos.
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void Instruction::moveBefore(Instruction *MovePos) {
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MovePos->getParent()->getInstList().splice(MovePos,getParent()->getInstList(),
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this);
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}
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const char *Instruction::getOpcodeName(unsigned OpCode) {
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switch (OpCode) {
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// Terminators
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case Ret: return "ret";
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case Br: return "br";
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case Switch: return "switch";
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case Invoke: return "invoke";
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case Unwind: return "unwind";
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case Unreachable: return "unreachable";
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// Standard binary operators...
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case Add: return "add";
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case FAdd: return "fadd";
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case Sub: return "sub";
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case FSub: return "fsub";
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case Mul: return "mul";
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case FMul: return "fmul";
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case UDiv: return "udiv";
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case SDiv: return "sdiv";
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case FDiv: return "fdiv";
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case URem: return "urem";
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case SRem: return "srem";
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case FRem: return "frem";
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// Logical operators...
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case And: return "and";
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case Or : return "or";
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case Xor: return "xor";
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// Memory instructions...
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case Malloc: return "malloc";
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case Free: return "free";
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case Alloca: return "alloca";
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case Load: return "load";
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case Store: return "store";
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case GetElementPtr: return "getelementptr";
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// Convert instructions...
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case Trunc: return "trunc";
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case ZExt: return "zext";
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case SExt: return "sext";
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case FPTrunc: return "fptrunc";
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case FPExt: return "fpext";
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case FPToUI: return "fptoui";
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case FPToSI: return "fptosi";
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case UIToFP: return "uitofp";
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case SIToFP: return "sitofp";
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case IntToPtr: return "inttoptr";
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case PtrToInt: return "ptrtoint";
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case BitCast: return "bitcast";
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// Other instructions...
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case ICmp: return "icmp";
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case FCmp: return "fcmp";
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case PHI: return "phi";
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case Select: return "select";
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case Call: return "call";
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case Shl: return "shl";
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case LShr: return "lshr";
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case AShr: return "ashr";
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case VAArg: return "va_arg";
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case ExtractElement: return "extractelement";
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case InsertElement: return "insertelement";
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case ShuffleVector: return "shufflevector";
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case ExtractValue: return "extractvalue";
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case InsertValue: return "insertvalue";
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default: return "<Invalid operator> ";
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}
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return 0;
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}
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/// isIdenticalTo - Return true if the specified instruction is exactly
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/// identical to the current one. This means that all operands match and any
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/// extra information (e.g. load is volatile) agree.
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bool Instruction::isIdenticalTo(const Instruction *I) const {
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if (getOpcode() != I->getOpcode() ||
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getNumOperands() != I->getNumOperands() ||
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getType() != I->getType())
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return false;
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// We have two instructions of identical opcode and #operands. Check to see
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// if all operands are the same.
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for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
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if (getOperand(i) != I->getOperand(i))
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return false;
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// Check special state that is a part of some instructions.
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if (const LoadInst *LI = dyn_cast<LoadInst>(this))
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return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
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LI->getAlignment() == cast<LoadInst>(I)->getAlignment();
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if (const StoreInst *SI = dyn_cast<StoreInst>(this))
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return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
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SI->getAlignment() == cast<StoreInst>(I)->getAlignment();
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if (const CmpInst *CI = dyn_cast<CmpInst>(this))
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return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
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if (const CallInst *CI = dyn_cast<CallInst>(this))
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return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
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CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<CallInst>(I)->getAttributes().getRawPointer();
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if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
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return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<InvokeInst>(I)->getAttributes().getRawPointer();
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if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) {
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if (IVI->getNumIndices() != cast<InsertValueInst>(I)->getNumIndices())
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return false;
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for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
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if (IVI->idx_begin()[i] != cast<InsertValueInst>(I)->idx_begin()[i])
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return false;
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return true;
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}
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if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) {
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if (EVI->getNumIndices() != cast<ExtractValueInst>(I)->getNumIndices())
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return false;
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for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
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if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I)->idx_begin()[i])
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return false;
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return true;
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}
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return true;
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}
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// isSameOperationAs
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// This should be kept in sync with isEquivalentOperation in
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// lib/Transforms/IPO/MergeFunctions.cpp.
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bool Instruction::isSameOperationAs(const Instruction *I) const {
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if (getOpcode() != I->getOpcode() ||
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getNumOperands() != I->getNumOperands() ||
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getType() != I->getType())
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return false;
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// We have two instructions of identical opcode and #operands. Check to see
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// if all operands are the same type
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for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
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if (getOperand(i)->getType() != I->getOperand(i)->getType())
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return false;
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// Check special state that is a part of some instructions.
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if (const LoadInst *LI = dyn_cast<LoadInst>(this))
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return LI->isVolatile() == cast<LoadInst>(I)->isVolatile() &&
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LI->getAlignment() == cast<LoadInst>(I)->getAlignment();
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if (const StoreInst *SI = dyn_cast<StoreInst>(this))
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return SI->isVolatile() == cast<StoreInst>(I)->isVolatile() &&
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SI->getAlignment() == cast<StoreInst>(I)->getAlignment();
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if (const CmpInst *CI = dyn_cast<CmpInst>(this))
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return CI->getPredicate() == cast<CmpInst>(I)->getPredicate();
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if (const CallInst *CI = dyn_cast<CallInst>(this))
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return CI->isTailCall() == cast<CallInst>(I)->isTailCall() &&
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CI->getCallingConv() == cast<CallInst>(I)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<CallInst>(I)->getAttributes().getRawPointer();
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if (const InvokeInst *CI = dyn_cast<InvokeInst>(this))
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return CI->getCallingConv() == cast<InvokeInst>(I)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<InvokeInst>(I)->getAttributes().getRawPointer();
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if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(this)) {
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if (IVI->getNumIndices() != cast<InsertValueInst>(I)->getNumIndices())
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return false;
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for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
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if (IVI->idx_begin()[i] != cast<InsertValueInst>(I)->idx_begin()[i])
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return false;
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return true;
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}
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if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(this)) {
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if (EVI->getNumIndices() != cast<ExtractValueInst>(I)->getNumIndices())
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return false;
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for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
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if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I)->idx_begin()[i])
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return false;
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return true;
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}
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return true;
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}
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/// isUsedOutsideOfBlock - Return true if there are any uses of I outside of the
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/// specified block. Note that PHI nodes are considered to evaluate their
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/// operands in the corresponding predecessor block.
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bool Instruction::isUsedOutsideOfBlock(const BasicBlock *BB) const {
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for (use_const_iterator UI = use_begin(), E = use_end(); UI != E; ++UI) {
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// PHI nodes uses values in the corresponding predecessor block. For other
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// instructions, just check to see whether the parent of the use matches up.
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const PHINode *PN = dyn_cast<PHINode>(*UI);
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if (PN == 0) {
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if (cast<Instruction>(*UI)->getParent() != BB)
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return true;
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continue;
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}
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if (PN->getIncomingBlock(UI) != BB)
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return true;
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}
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return false;
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}
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/// mayReadFromMemory - Return true if this instruction may read memory.
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///
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bool Instruction::mayReadFromMemory() const {
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switch (getOpcode()) {
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default: return false;
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case Instruction::Free:
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case Instruction::VAArg:
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case Instruction::Load:
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return true;
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case Instruction::Call:
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return !cast<CallInst>(this)->doesNotAccessMemory();
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case Instruction::Invoke:
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return !cast<InvokeInst>(this)->doesNotAccessMemory();
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case Instruction::Store:
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return cast<StoreInst>(this)->isVolatile();
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}
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}
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/// mayWriteToMemory - Return true if this instruction may modify memory.
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///
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bool Instruction::mayWriteToMemory() const {
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switch (getOpcode()) {
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default: return false;
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case Instruction::Free:
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case Instruction::Store:
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case Instruction::VAArg:
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return true;
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case Instruction::Call:
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return !cast<CallInst>(this)->onlyReadsMemory();
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case Instruction::Invoke:
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return !cast<InvokeInst>(this)->onlyReadsMemory();
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case Instruction::Load:
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return cast<LoadInst>(this)->isVolatile();
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}
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}
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/// mayThrow - Return true if this instruction may throw an exception.
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///
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bool Instruction::mayThrow() const {
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if (const CallInst *CI = dyn_cast<CallInst>(this))
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return !CI->doesNotThrow();
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return false;
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}
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/// isAssociative - Return true if the instruction is associative:
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///
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/// Associative operators satisfy: x op (y op z) === (x op y) op z
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///
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/// In LLVM, the Add, Mul, And, Or, and Xor operators are associative.
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///
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bool Instruction::isAssociative(unsigned Opcode, const Type *Ty) {
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return Opcode == And || Opcode == Or || Opcode == Xor ||
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Opcode == Add || Opcode == Mul;
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}
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/// isCommutative - Return true if the instruction is commutative:
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///
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/// Commutative operators satisfy: (x op y) === (y op x)
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///
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/// In LLVM, these are the associative operators, plus SetEQ and SetNE, when
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/// applied to any type.
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///
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bool Instruction::isCommutative(unsigned op) {
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switch (op) {
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case Add:
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case FAdd:
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case Mul:
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case FMul:
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case And:
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case Or:
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case Xor:
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return true;
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default:
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return false;
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}
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}
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bool Instruction::isSafeToSpeculativelyExecute() const {
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for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
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if (Constant *C = dyn_cast<Constant>(getOperand(i)))
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if (C->canTrap())
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return false;
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switch (getOpcode()) {
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default:
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return true;
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case UDiv:
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case URem: {
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// x / y is undefined if y == 0, but calcuations like x / 3 are safe.
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ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
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return Op && !Op->isNullValue();
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}
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case SDiv:
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case SRem: {
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// x / y is undefined if y == 0, and might be undefined if y == -1,
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// but calcuations like x / 3 are safe.
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ConstantInt *Op = dyn_cast<ConstantInt>(getOperand(1));
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return Op && !Op->isNullValue() && !Op->isAllOnesValue();
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}
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case Load: {
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if (cast<LoadInst>(this)->isVolatile())
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return false;
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if (isa<AllocationInst>(getOperand(0)))
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return true;
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if (GlobalVariable *GV = dyn_cast<GlobalVariable>(getOperand(0)))
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return !GV->hasExternalWeakLinkage();
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// FIXME: Handle cases involving GEPs. We have to be careful because
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// a load of a out-of-bounds GEP has undefined behavior.
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return false;
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}
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case Call:
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return false; // The called function could have undefined behavior or
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// side-effects.
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// FIXME: We should special-case some intrinsics (bswap,
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// overflow-checking arithmetic, etc.)
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case VAArg:
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case Alloca:
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case Malloc:
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case Invoke:
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case PHI:
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case Store:
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case Free:
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case Ret:
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case Br:
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case Switch:
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case Unwind:
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case Unreachable:
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return false; // Misc instructions which have effects
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}
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}
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