Imported Upstream version 5.18.0.234

Former-commit-id: 8071ec1a8c5eaa9be24b41745add19297608001f

external/llvm/lib/Transforms/IPO/ElimAvailExtern.cpp

@@ -1,102 +0,0 @@
-//===- ElimAvailExtern.cpp - DCE unreachable internal functions -----------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This transform is designed to eliminate available external global
-// definitions from the program, turning them into declarations.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/IPO/ElimAvailExtern.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/IR/Constant.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/GlobalValue.h"
-#include "llvm/IR/GlobalVariable.h"
-#include "llvm/IR/Module.h"
-#include "llvm/Pass.h"
-#include "llvm/Transforms/IPO.h"
-#include "llvm/Transforms/Utils/GlobalStatus.h"
-
-using namespace llvm;
-
-#define DEBUG_TYPE "elim-avail-extern"
-
-STATISTIC(NumFunctions, "Number of functions removed");
-STATISTIC(NumVariables, "Number of global variables removed");
-
-static bool eliminateAvailableExternally(Module &M) {
-  bool Changed = false;
-
-  // Drop initializers of available externally global variables.
-  for (GlobalVariable &GV : M.globals()) {
-    if (!GV.hasAvailableExternallyLinkage())
-      continue;
-    if (GV.hasInitializer()) {
-      Constant *Init = GV.getInitializer();
-      GV.setInitializer(nullptr);
-      if (isSafeToDestroyConstant(Init))
-        Init->destroyConstant();
-    }
-    GV.removeDeadConstantUsers();
-    GV.setLinkage(GlobalValue::ExternalLinkage);
-    NumVariables++;
-    Changed = true;
-  }
-
-  // Drop the bodies of available externally functions.
-  for (Function &F : M) {
-    if (!F.hasAvailableExternallyLinkage())
-      continue;
-    if (!F.isDeclaration())
-      // This will set the linkage to external
-      F.deleteBody();
-    F.removeDeadConstantUsers();
-    NumFunctions++;
-    Changed = true;
-  }
-
-  return Changed;
-}
-
-PreservedAnalyses
-EliminateAvailableExternallyPass::run(Module &M, ModuleAnalysisManager &) {
-  if (!eliminateAvailableExternally(M))
-    return PreservedAnalyses::all();
-  return PreservedAnalyses::none();
-}
-
-namespace {
-
-struct EliminateAvailableExternallyLegacyPass : public ModulePass {
-  static char ID; // Pass identification, replacement for typeid
-
-  EliminateAvailableExternallyLegacyPass() : ModulePass(ID) {
-    initializeEliminateAvailableExternallyLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  // run - Do the EliminateAvailableExternally pass on the specified module,
-  // optionally updating the specified callgraph to reflect the changes.
-  bool runOnModule(Module &M) override {
-    if (skipModule(M))
-      return false;
-    return eliminateAvailableExternally(M);
-  }
-};
-
-} // end anonymous namespace
-
-char EliminateAvailableExternallyLegacyPass::ID = 0;
-
-INITIALIZE_PASS(EliminateAvailableExternallyLegacyPass, "elim-avail-extern",
-                "Eliminate Available Externally Globals", false, false)
-
-ModulePass *llvm::createEliminateAvailableExternallyPass() {
-  return new EliminateAvailableExternallyLegacyPass();
-}