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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 "Delta.h"
#include "Utils.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include <iterator>
#include <vector>
using namespace llvm;
/// Removes all the Defined Functions
/// that aren't inside any of the desired Chunks.
static void extractFunctionsFromModule(Oracle &O, Module &Program) {
// Record all out-of-chunk functions.
std::vector<std::reference_wrapper<Function>> FuncsToRemove;
copy_if(Program.functions(), std::back_inserter(FuncsToRemove),
[&O](Function &F) {
// 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.
return (!F.isIntrinsic() || F.use_empty()) && !O.shouldKeep();
});
// Then, drop body of each of them. We want to batch this and do nothing else
// here so that minimal number of remaining exteranal uses will remain.
for (Function &F : FuncsToRemove)
F.dropAllReferences();
// And finally, we can actually delete them.
for (Function &F : FuncsToRemove) {
// Replace all *still* remaining uses with the default value.
F.replaceAllUsesWith(getDefaultValue(F.getType()));
// And finally, fully drop it.
F.eraseFromParent();
}
}
void llvm::reduceFunctionsDeltaPass(TestRunner &Test) {
errs() << "*** Reducing Functions...\n";
runDeltaPass(Test, extractFunctionsFromModule);
errs() << "----------------------------\n";
}
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