ReduceFunctions.cpp
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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 "llvm/ADT/SetVector.h"
#include <set>
using namespace llvm;
/// Removes all the Defined Functions (as well as their calls)
/// that aren't inside any of the desired Chunks.
static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
Module *Program) {
// Get functions inside desired chunks
std::set<Function *> FuncsToKeep;
int I = 0, FunctionCount = 0;
for (auto &F : *Program)
if (I < (int)ChunksToKeep.size()) {
if (ChunksToKeep[I].contains(++FunctionCount))
FuncsToKeep.insert(&F);
if (FunctionCount == ChunksToKeep[I].end)
++I;
}
// Delete out-of-chunk functions, and replace their calls with undef
std::vector<Function *> FuncsToRemove;
SetVector<CallInst *> CallsToRemove;
for (auto &F : *Program)
if (!FuncsToKeep.count(&F)) {
for (auto U : F.users())
if (auto *Call = dyn_cast<CallInst>(U)) {
Call->replaceAllUsesWith(UndefValue::get(Call->getType()));
CallsToRemove.insert(Call);
}
F.replaceAllUsesWith(UndefValue::get(F.getType()));
FuncsToRemove.push_back(&F);
}
for (auto *C : CallsToRemove)
C->eraseFromParent();
for (auto *F : FuncsToRemove)
F->eraseFromParent();
}
/// Counts the amount of non-declaration functions and prints their
/// respective name & index
static int countFunctions(Module *Program) {
// TODO: Silence index with --quiet flag
errs() << "----------------------------\n";
errs() << "Function Index Reference:\n";
int FunctionCount = 0;
for (auto &F : *Program)
errs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n";
errs() << "----------------------------\n";
return FunctionCount;
}
void llvm::reduceFunctionsDeltaPass(TestRunner &Test) {
errs() << "*** Reducing Functions...\n";
int Functions = countFunctions(Test.getProgram());
runDeltaPass(Test, Functions, extractFunctionsFromModule);
errs() << "----------------------------\n";
}