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
  17 /// Removes all the Defined Functions (as well as their calls)
  18 /// that aren't inside any of the desired Chunks.
  19 static void extractFunctionsFromModule(const std::vector<Chunk> &ChunksToKeep,
  20                                        Module *Program) {
  21   // Get functions inside desired chunks
  22   std::set<Function *> FuncsToKeep;
  23   unsigned I = 0, FunctionCount = 0;
  24   for (auto &F : *Program)
  25     if (I < ChunksToKeep.size()) {
  26       if (ChunksToKeep[I].contains(++FunctionCount))
  27         FuncsToKeep.insert(&F);
  28       if (FunctionCount == ChunksToKeep[I].end)
  29         ++I;
  30     }
  31
  32   // Delete out-of-chunk functions, and replace their calls with undef
  33   std::vector<Function *> FuncsToRemove;
  34   std::vector<CallInst *> CallsToRemove;
  35   for (auto &F : *Program)
  36     if (!FuncsToKeep.count(&F)) {
  37       for (auto U : F.users())
  38         if (auto *Call = dyn_cast<CallInst>(U)) {
  39           Call->replaceAllUsesWith(UndefValue::get(Call->getType()));
  40           CallsToRemove.push_back(Call);
  41         }
  42       F.replaceAllUsesWith(UndefValue::get(F.getType()));
  43       FuncsToRemove.push_back(&F);
  44     }
  45
  46   for (auto *C : CallsToRemove)
  47     C->eraseFromParent();
  48
  49   for (auto *F : FuncsToRemove)
  50     F->eraseFromParent();
  51 }
  52
  53 /// Counts the amount of non-declaration functions and prints their
  54 /// respective name & index
  55 static unsigned countFunctions(Module *Program) {
  56   // TODO: Silence index with --quiet flag
  57   errs() << "----------------------------\n";
  58   errs() << "Function Index Reference:\n";
  59   unsigned FunctionCount = 0;
  60   for (auto &F : *Program)
  61     errs() << "\t" << ++FunctionCount << ": " << F.getName() << "\n";
  62
  63   errs() << "----------------------------\n";
  64   return FunctionCount;
  65 }
  66
  67 void llvm::reduceFunctionsDeltaPass(TestRunner &Test) {
  68   errs() << "*** Reducing Functions...\n";
  69   unsigned Functions = countFunctions(Test.getProgram());
  70   runDeltaPass(Test, Functions, extractFunctionsFromModule);
  71   errs() << "----------------------------\n";
  72 }