Mangling.cpp

//===----------- Mangling.cpp -- Name Mangling Utilities for ORC ----------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/ExecutionEngine/Orc/Mangling.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Mangler.h"
#include "llvm/Support/Debug.h"

#define DEBUG_TYPE "orc"

namespace llvm {
namespace orc {

MangleAndInterner::MangleAndInterner(ExecutionSession &ES, const DataLayout &DL)
    : ES(ES), DL(DL) {}

SymbolStringPtr MangleAndInterner::operator()(StringRef Name) {
  std::string MangledName;
  {
    raw_string_ostream MangledNameStream(MangledName);
    Mangler::getNameWithPrefix(MangledNameStream, Name, DL);
  }
  return ES.intern(MangledName);
}

void IRSymbolMapper::add(ExecutionSession &ES, const ManglingOptions &MO,
                         ArrayRef<GlobalValue *> GVs,
                         SymbolFlagsMap &SymbolFlags,
                         SymbolNameToDefinitionMap *SymbolToDefinition) {
  if (GVs.empty())
    return;

  MangleAndInterner Mangle(ES, GVs[0]->getDataLayout());
  for (auto *G : GVs) {
    assert(G && "GVs cannot contain null elements");
    if (!G->hasName() || G->isDeclaration() || G->hasLocalLinkage() ||
        G->hasAvailableExternallyLinkage() || G->hasAppendingLinkage())
      continue;

    if (G->isThreadLocal() && MO.EmulatedTLS) {
      auto *GV = cast<GlobalVariable>(G);

      auto Flags = JITSymbolFlags::fromGlobalValue(*GV);

      auto EmuTLSV = Mangle(("__emutls_v." + GV->getName()).str());
      SymbolFlags[EmuTLSV] = Flags;
      if (SymbolToDefinition)
        (*SymbolToDefinition)[EmuTLSV] = GV;

      // If this GV has a non-zero initializer we'll need to emit an
      // __emutls.t symbol too.
      if (GV->hasInitializer()) {
        const auto *InitVal = GV->getInitializer();

        // Skip zero-initializers.
        if (isa<ConstantAggregateZero>(InitVal))
          continue;
        const auto *InitIntValue = dyn_cast<ConstantInt>(InitVal);
        if (InitIntValue && InitIntValue->isZero())
          continue;

        auto EmuTLST = Mangle(("__emutls_t." + GV->getName()).str());
        SymbolFlags[EmuTLST] = Flags;
        if (SymbolToDefinition)
          (*SymbolToDefinition)[EmuTLST] = GV;
      }
      continue;
    }

    // Otherwise we just need a normal linker mangling.
    auto MangledName = Mangle(G->getName());
    SymbolFlags[MangledName] = JITSymbolFlags::fromGlobalValue(*G);
    if (SymbolToDefinition)
      (*SymbolToDefinition)[MangledName] = G;
  }
}

} // End namespace orc.
} // End namespace llvm.