New pass to make internal linkage symbol names unique.

With clang option -funique-internal-linkage-symbols, symbols with
internal linkage get names with the module hash appended.

Differential Revision: https://reviews.llvm.org/D78243

include/llvm/InitializePasses.h

@@ -304,6 +304,7 @@ void initializeModuloScheduleTestPass(PassRegistry&);
 void initializeMustExecutePrinterPass(PassRegistry&);
 void initializeMustBeExecutedContextPrinterPass(PassRegistry&);
 void initializeNameAnonGlobalLegacyPassPass(PassRegistry&);
+void initializeUniqueInternalLinkageNamesLegacyPassPass(PassRegistry &);
 void initializeNaryReassociateLegacyPassPass(PassRegistry&);
 void initializeNewGVNLegacyPassPass(PassRegistry&);
 void initializeObjCARCAAWrapperPassPass(PassRegistry&);

include/llvm/Transforms/Utils.h

@@ -25,6 +25,12 @@ class Pass;
 //
 ModulePass *createMetaRenamerPass();
 
+//===----------------------------------------------------------------------===//
+// createUniqueInternalLinkageNamesPass - Make internal linkage symbol names
+// unique.
+//
+ModulePass *createUniqueInternalLinkageNamesPass();
+
 //===----------------------------------------------------------------------===//
 //
 // LowerInvoke - This pass removes invoke instructions, converting them to call

include/llvm/Transforms/Utils/UniqueInternalLinkageNames.h

@@ -0,0 +1,31 @@
+//===-- UniqueInternalLinkageNames.h - Uniq. Int. Linkage Names -*- C++ -*-===//
+//
+// 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 unique naming of internal linkage symbols with option
+// -funique-internal-linkage-symbols.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_UTILS_UNIQUEINTERNALLINKAGENAMES_H
+#define LLVM_TRANSFORMS_UTILS_UNIQUEINTERNALLINKAGENAMES_H
+
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// Simple pass that provides a name to every anonymous globals.
+class UniqueInternalLinkageNamesPass
+    : public PassInfoMixin<UniqueInternalLinkageNamesPass> {
+public:
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_UTILS_UNIQUEINTERNALLINKAGENAMES_H

lib/Transforms/Utils/CMakeLists.txt

@@ -65,6 +65,7 @@ add_llvm_component_library(LLVMTransformUtils
   SymbolRewriter.cpp
   UnifyFunctionExitNodes.cpp
   UnifyLoopExits.cpp
+  UniqueInternalLinkageNames.cpp
   Utils.cpp
   ValueMapper.cpp
   VNCoercion.cpp

lib/Transforms/Utils/UniqueInternalLinkageNames.cpp

@@ -0,0 +1,97 @@
+//===- UniqueInternalLinkageNames.cpp - Unique Internal Linkage Sym Names -===//
+//
+// 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 unique naming of internal linkage symbols with option
+// -funique-internal-linkage-symbols.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/UniqueInternalLinkageNames.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/IR/Module.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/MD5.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
+
+using namespace llvm;
+
+static bool uniqueifyInternalLinkageNames(Module &M) {
+  llvm::MD5 Md5;
+  Md5.update(M.getSourceFileName());
+  llvm::MD5::MD5Result R;
+  Md5.final(R);
+  SmallString<32> Str;
+  llvm::MD5::stringifyResult(R, Str);
+  std::string ModuleNameHash = (Twine(".") + Twine(Str)).str();
+  bool Changed = false;
+
+  // Append the module hash to all internal linkage functions.
+  for (auto &F : M) {
+    if (F.hasInternalLinkage()) {
+      F.setName(F.getName() + ModuleNameHash);
+      Changed = true;
+    }
+  }
+
+  // Append the module hash to all internal linkage globals.
+  for (auto &GV : M.globals()) {
+    if (GV.hasInternalLinkage()) {
+      GV.setName(GV.getName() + ModuleNameHash);
+      Changed = true;
+    }
+  }
+  return Changed;
+}
+
+namespace {
+
+// Legacy pass that provides a name to every anon globals.
+class UniqueInternalLinkageNamesLegacyPass : public ModulePass {
+
+public:
+  /// Pass identification, replacement for typeid
+  static char ID;
+
+  /// Specify pass name for debug output
+  StringRef getPassName() const override {
+    return "Unique Internal Linkage Names";
+  }
+
+  explicit UniqueInternalLinkageNamesLegacyPass() : ModulePass(ID) {
+    initializeUniqueInternalLinkageNamesLegacyPassPass(
+        *PassRegistry::getPassRegistry());
+  }
+
+  bool runOnModule(Module &M) override {
+    return uniqueifyInternalLinkageNames(M);
+  }
+};
+
+char UniqueInternalLinkageNamesLegacyPass::ID = 0;
+} // anonymous namespace
+
+PreservedAnalyses
+UniqueInternalLinkageNamesPass::run(Module &M, ModuleAnalysisManager &AM) {
+  if (!uniqueifyInternalLinkageNames(M))
+    return PreservedAnalyses::all();
+
+  return PreservedAnalyses::none();
+}
+
+INITIALIZE_PASS_BEGIN(UniqueInternalLinkageNamesLegacyPass,
+                      "unique-internal-linkage-names",
+                      "Uniqueify internal linkage names", false, false)
+INITIALIZE_PASS_END(UniqueInternalLinkageNamesLegacyPass,
+                    "unique-internal-linkage-names",
+                    "Uniqueify Internal linkage names", false, false)
+
+namespace llvm {
+ModulePass *createUniqueInternalLinkageNamesPass() {
+  return new UniqueInternalLinkageNamesLegacyPass();
+}
+} // namespace llvm

lib/Transforms/Utils/Utils.cpp

@@ -42,6 +42,7 @@ void llvm::initializeTransformUtils(PassRegistry &Registry) {
   initializeInjectTLIMappingsLegacyPass(Registry);
   initializeFixIrreduciblePass(Registry);
   initializeUnifyLoopExitsPass(Registry);
+  initializeUniqueInternalLinkageNamesLegacyPassPass(Registry);
 }
 
 /// LLVMInitializeTransformUtils - C binding for initializeTransformUtilsPasses.

test/Transforms/UniqueInternalLinkageNames/unique_symbol_names.ll

@@ -0,0 +1,13 @@
+; RUN: opt -S -unique-internal-linkage-names < %s | FileCheck %s
+
+source_filename = "foo.c"
+
+@glob = internal global i32 0
+
+define internal i32 @foo() {
+entry:
+  ret i32 0
+}
+
+; CHECK: @glob.6ae72bb15a7d1834b42ae042a58f7a4d = internal global
+; CHECK: define internal i32 @foo.6ae72bb15a7d1834b42ae042a58f7a4d()

utils/gn/secondary/llvm/lib/Transforms/Utils/BUILD.gn

@@ -72,6 +72,7 @@ static_library("Utils") {
     "SymbolRewriter.cpp",
     "UnifyFunctionExitNodes.cpp",
     "UnifyLoopExits.cpp",
+    "UniqueInternalLinkageNames.cpp",
     "Utils.cpp",
     "VNCoercion.cpp",
     "ValueMapper.cpp",