llvm/lib/Analysis/ValueLatticeUtils.cpp

   1 //===-- ValueLatticeUtils.cpp - Utils for solving lattices ------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements common functions useful for performing data-flow
  10 // analyses that propagate values across function boundaries.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Analysis/ValueLatticeUtils.h"
  15 #include "llvm/IR/GlobalVariable.h"
  16 #include "llvm/IR/Instructions.h"
  17 using namespace llvm;
  18
  19 bool llvm::canTrackArgumentsInterprocedurally(Function *F) {
  20   return F->hasLocalLinkage() && !F->hasAddressTaken();
  21 }
  22
  23 bool llvm::canTrackReturnsInterprocedurally(Function *F) {
  24   return F->hasExactDefinition() && !F->hasFnAttribute(Attribute::Naked);
  25 }
  26
  27 bool llvm::canTrackGlobalVariableInterprocedurally(GlobalVariable *GV) {
  28   if (GV->isConstant() || !GV->hasLocalLinkage() ||
  29       !GV->hasDefinitiveInitializer())
  30     return false;
  31   return all_of(GV->users(), [&](User *U) {
  32     // Currently all users of a global variable have to be non-volatile loads
  33     // or stores of the global type, and the global cannot be stored itself.
  34     if (auto *Store = dyn_cast<StoreInst>(U))
  35       return Store->getValueOperand() != GV && !Store->isVolatile() &&
  36              Store->getValueOperand()->getType() == GV->getValueType();
  37     if (auto *Load = dyn_cast<LoadInst>(U))
  38       return !Load->isVolatile() && Load->getType() == GV->getValueType();
  39
  40     return false;
  41   });
  42 }