1 files changed, 77 insertions, 0 deletions
diff --git a/tools/llvm-reduce/deltas/ReduceFunctions.cpp b/tools/llvm-reduce/deltas/ReduceFunctions.cpp
new file mode 100644
index 000000000000..3382f35a945a
--- /dev/null
+++ b/tools/llvm-reduce/deltas/ReduceFunctions.cpp
@@ -0,0 +1,77 @@
+//===- 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";
+}