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2f56715ea7
It is not enough to replace all uses of users of the function with undef, the users, we only drop instruction users, so they may stick around. Let's try different approach - first drop bodies for all the functions we will drop, which should take care of blockaddress issue the previous rewrite was dealing with; then, after dropping *all* such bodies, replace remaining uses with undef (thus all the uses are either outside of functions, or are in kept functions) and then finally drop functions. This seems to work, and passes the *existing* test coverage, but it is possible that a new issue will be discovered later :) A new (previously crashing) test added.
69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
//===- ReduceFunctions.cpp - Specialized Delta Pass -----------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements a function which calls the Generic Delta pass in order
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// to reduce functions (and any instruction that calls it) in the provided
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// Module.
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//
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//===----------------------------------------------------------------------===//
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#include "ReduceFunctions.h"
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#include "Delta.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/IR/Instructions.h"
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#include <iterator>
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#include <vector>
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using namespace llvm;
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/// Removes all the Defined Functions
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/// that aren't inside any of the desired Chunks.
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static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
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Module *Program) {
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Oracle O(ChunksToKeep);
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// Record all out-of-chunk functions.
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std::vector<std::reference_wrapper<Function>> FuncsToRemove;
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copy_if(Program->functions(), std::back_inserter(FuncsToRemove),
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[&O](auto &unused) { return !O.shouldKeep(); });
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// Then, drop body of each of them. We want to batch this and do nothing else
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// here so that minimal number of remaining exteranal uses will remain.
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for (Function &F : FuncsToRemove)
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F.dropAllReferences();
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// And finally, we can actually delete them.
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for (Function &F : FuncsToRemove) {
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// Replace all *still* remaining uses with undef.
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F.replaceAllUsesWith(UndefValue::get(F.getType()));
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// And finally, fully drop it.
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F.eraseFromParent();
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}
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}
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/// Counts the amount of non-declaration functions and prints their
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/// respective name & index
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static int countFunctions(Module *Program) {
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// TODO: Silence index with --quiet flag
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errs() << "----------------------------\n";
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errs() << "Function Index Reference:\n";
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int FunctionCount = 0;
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for (auto &F : *Program)
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errs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n";
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errs() << "----------------------------\n";
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return FunctionCount;
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}
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void llvm::reduceFunctionsDeltaPass(TestRunner &Test) {
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errs() << "*** Reducing Functions...\n";
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int Functions = countFunctions(Test.getProgram());
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runDeltaPass(Test, Functions, extractFunctionsFromModule);
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errs() << "----------------------------\n";
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}
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