forked from OSchip/llvm-project
78 lines
2.8 KiB
C++
78 lines
2.8 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](Function &F) {
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// Intrinsics don't have function bodies that are useful to
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// reduce. Additionally, intrinsics may have additional operand
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// constraints. But, do drop intrinsics that are not referenced.
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return (!F.isIntrinsic() || F.use_empty()) && !O.shouldKeep();
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});
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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 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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if (F.isIntrinsic() && !F.use_empty())
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continue;
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errs() << '\t' << ++FunctionCount << ": " << F.getName() << '\n';
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}
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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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