AIELLVMLink.cpp

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//===- LLVMLink.cpp ---------------------------------------------*- C++ -*-===//
//
// Copyright (C) 2021-2022 Xilinx, Inc.
// Copyright (C) 2022-2023 Advanced Micro Devices, Inc.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
// This is basically copy-pasta from llvm/tools/llvm-link/llvm-link.cpp but
// rewritten to take strings as input instead of files. Comments are preserved
// in case you need to go back to the source and compare/contrast.
 
#include "aie/Targets/AIETargets.h"
 
#include "mlir/Support/LogicalResult.h"
 
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/IR/AutoUpgrade.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Linker/Linker.h"
#include "llvm/Object/Archive.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Transforms/IPO/Internalize.h"
 
#include <memory>
#include <utility>
 
using namespace llvm;
 
static std::unique_ptr<Module> loadFile(std::unique_ptr<MemoryBuffer> Buffer,
                                        LLVMContext &Context, bool Verbose,
                                        bool MaterializeMetadata = true) {
  SMDiagnostic Err;
  if (Verbose)
    errs() << "Loading '" << Buffer->getBufferIdentifier() << "'\n";
  std::unique_ptr<Module> Result;
  Result = parseIR(*Buffer, Err, Context);
  if (!Result) {
    Err.print("aie-llvm-Link", errs());
    return nullptr;
  }
 
  if (MaterializeMetadata) {
    // this call return an error that convert true if there was in fact an
    // error...
    if (Result->materializeMetadata()) {
      Err.print("aie-llvm-link", errs());
      return nullptr;
    }
    UpgradeDebugInfo(*Result);
  }
 
  return Result;
}
 
static mlir::LogicalResult linkFiles(const std::vector<std::string> &Files,
                                     LLVMContext &Context, Linker &L,
                                     unsigned Flags, bool DisableDITypeMap,
                                     bool NoVerify, bool Internalize,
                                     bool Verbose) {
  // Filter out flags that don't apply to the first file we load.
  unsigned ApplicableFlags = Flags & Linker::Flags::OverrideFromSrc;
  // Similar to some flags, internalization doesn't apply to the first file.
  bool InternalizeLinkedSymbols = false;
  for (const auto &File : Files) {
    std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBufferCopy(File);
 
    std::unique_ptr<Module> maybeModule =
        loadFile(std::move(Buffer), Context, Verbose);
    if (!maybeModule) {
      WithColor::error() << " loading file '" << File << "'\n";
      return mlir::failure();
    }
 
    // Note that when ODR merging types cannot verify input files in here When
    // doing that debug metadata in the src module might already be pointing to
    // the destination.
    if (DisableDITypeMap && !NoVerify && verifyModule(*maybeModule, &errs())) {
      WithColor::error() << "input module is broken!\n";
      return mlir::failure();
    }
 
    if (Verbose)
      errs() << "Linking in '" << File << "'\n";
 
    bool Err;
    if (InternalizeLinkedSymbols)
      Err = L.linkInModule(
          std::move(maybeModule), ApplicableFlags,
          [](Module &M, const StringSet<> &GVS) {
            internalizeModule(M, [&GVS](const GlobalValue &GV) {
              return !GV.hasName() || (GVS.count(GV.getName()) == 0);
            });
          });
    else
      Err = L.linkInModule(std::move(maybeModule), ApplicableFlags);
 
    if (Err) {
      errs() << "couldn't link.\n";
      return mlir::failure();
    }
 
    // Internalization applies to linking of subsequent files.
    InternalizeLinkedSymbols = Internalize;
 
    // All linker flags apply to linking of subsequent files.
    ApplicableFlags = Flags;
  }
 
  return mlir::success();
}
 
mlir::LogicalResult xilinx::AIE::AIELLVMLink(
    llvm::raw_ostream &output, const std::vector<std::string> &Files,
    bool DisableDITypeMap, bool NoVerify, bool Internalize, bool OnlyNeeded,
    bool PreserveAssemblyUseListOrder, bool Verbose) {
  LLVMContext Context;
 
  if (!DisableDITypeMap)
    Context.enableDebugTypeODRUniquing();
 
  auto Composite = std::make_unique<Module>("aie-llvm-link", Context);
  Linker L(*Composite);
 
  unsigned Flags = Linker::Flags::None;
  if (OnlyNeeded)
    Flags |= Linker::Flags::LinkOnlyNeeded;
 
  // First add all the regular input files
  if (failed(linkFiles(Files, Context, L, Flags, DisableDITypeMap, NoVerify,
                       Internalize, Verbose)))
    return mlir::failure();
 
  Composite->print(output, nullptr, PreserveAssemblyUseListOrder);
  return mlir::success();
}