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//===- ReduceFunctions.cpp - Specialized Delta Pass -----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements a function which calls the Generic Delta pass in order
// to reduce functions (and any instruction that calls it) in the provided
// Module.
//
//===----------------------------------------------------------------------===//
#include "ReduceFunctions.h"
#include "Utils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;
/// Removes all the Defined Functions
/// that aren't inside any of the desired Chunks.
void llvm::reduceFunctionsDeltaPass(Oracle &O, ReducerWorkItem &WorkItem) {
Module &Program = WorkItem.getModule();
// Record all out-of-chunk functions.
SmallPtrSet<Constant *, 8> FuncsToRemove;
for (Function &F : Program.functions()) {
// Intrinsics don't have function bodies that are useful to
// reduce. Additionally, intrinsics may have additional operand
// constraints. But, do drop intrinsics that are not referenced.
if ((!F.isIntrinsic() || F.use_empty()) && !hasAliasUse(F) &&
!O.shouldKeep())
FuncsToRemove.insert(&F);
}
removeFromUsedLists(Program, [&FuncsToRemove](Constant *C) {
return FuncsToRemove.count(C);
});
// Then, drop body of each of them. We want to batch this and do nothing else
// here so that minimal number of remaining external uses will remain.
for (Constant *F : FuncsToRemove)
F->dropAllReferences();
// And finally, we can actually delete them.
for (Constant *F : FuncsToRemove) {
// Replace all *still* remaining uses with the default value.
F->replaceAllUsesWith(getDefaultValue(F->getType()));
// And finally, fully drop it.
cast<Function>(F)->eraseFromParent();
}
}
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