tools/llvm-reduce/deltas/ReduceFunctions.cpp

   1 //===- ReduceFunctions.cpp - Specialized Delta Pass -----------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements a function which calls the Generic Delta pass in order
  10 // to reduce functions (and any instruction that calls it) in the provided
  11 // Module.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "ReduceFunctions.h"
  16 #include "Delta.h"
  17 #include "llvm/ADT/SetVector.h"
  18 #include <set>
  19
  20 using namespace llvm;
  21
  22 /// Removes all the Defined Functions (as well as their calls)
  23 /// that aren't inside any of the desired Chunks.
  24 static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
  25                                        Module *Program) {
  26   // Get functions inside desired chunks
  27   std::set<Function *> FuncsToKeep;
  28   int I = 0, FunctionCount = 0;
  29   for (auto &F : *Program)
  30     if (I < (int)ChunksToKeep.size()) {
  31       if (ChunksToKeep[I].contains(++FunctionCount))
  32         FuncsToKeep.insert(&F);
  33       if (FunctionCount == ChunksToKeep[I].end)
  34         ++I;
  35     }
  36
  37   // Delete out-of-chunk functions, and replace their calls with undef
  38   std::vector<Function *> FuncsToRemove;
  39   SetVector<CallInst *> CallsToRemove;
  40   for (auto &F : *Program)
  41     if (!FuncsToKeep.count(&F)) {
  42       for (auto U : F.users())
  43         if (auto *Call = dyn_cast<CallInst>(U)) {
  44           Call->replaceAllUsesWith(UndefValue::get(Call->getType()));
  45           CallsToRemove.insert(Call);
  46         }
  47       F.replaceAllUsesWith(UndefValue::get(F.getType()));
  48       FuncsToRemove.push_back(&F);
  49     }
  50
  51   for (auto *C : CallsToRemove)
  52     C->eraseFromParent();
  53
  54   for (auto *F : FuncsToRemove)
  55     F->eraseFromParent();
  56 }
  57
  58 /// Counts the amount of non-declaration functions and prints their
  59 /// respective name & index
  60 static int countFunctions(Module *Program) {
  61   // TODO: Silence index with --quiet flag
  62   errs() << "----------------------------\n";
  63   errs() << "Function Index Reference:\n";
  64   int FunctionCount = 0;
  65   for (auto &F : *Program)
  66     errs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n";
  67
  68   errs() << "----------------------------\n";
  69   return FunctionCount;
  70 }
  71
  72 void llvm::reduceFunctionsDeltaPass(TestRunner &Test) {
  73   errs() << "*** Reducing Functions...\n";
  74   int Functions = countFunctions(Test.getProgram());
  75   runDeltaPass(Test, Functions, extractFunctionsFromModule);
  76   errs() << "----------------------------\n";
  77 }