bolt/lib/RuntimeLibs/HugifyRuntimeLibrary.cpp

   1 //===- bolt/RuntimeLibs/HugifyRuntimeLibrary.cpp - Hugify RT Library ------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements the HugifyRuntimeLibrary class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "bolt/RuntimeLibs/HugifyRuntimeLibrary.h"
  14 #include "bolt/Core/BinaryContext.h"
  15 #include "bolt/Core/Linker.h"
  16 #include "llvm/MC/MCStreamer.h"
  17 #include "llvm/Support/CommandLine.h"
  18
  19 using namespace llvm;
  20 using namespace bolt;
  21
  22 namespace opts {
  23
  24 extern cl::OptionCategory BoltOptCategory;
  25
  26 extern cl::opt<bool> HotText;
  27
  28 cl::opt<bool>
  29     Hugify("hugify",
  30            cl::desc("Automatically put hot code on 2MB page(s) (hugify) at "
  31                     "runtime. No manual call to hugify is needed in the binary "
  32                     "(which is what --hot-text relies on)."),
  33            cl::cat(BoltOptCategory));
  34
  35 static cl::opt<std::string>
  36     RuntimeHugifyLib("runtime-hugify-lib",
  37                      cl::desc("specify path of the runtime hugify library"),
  38                      cl::init("libbolt_rt_hugify.a"), cl::cat(BoltOptCategory));
  39
  40 } // namespace opts
  41
  42 void HugifyRuntimeLibrary::adjustCommandLineOptions(
  43     const BinaryContext &BC) const {
  44   if (opts::HotText) {
  45     errs()
  46         << "BOLT-ERROR: -hot-text should be applied to binaries with "
  47            "pre-compiled manual hugify support, while -hugify will add hugify "
  48            "support automatically. These two options cannot both be present.\n";
  49     exit(1);
  50   }
  51   // After the check, we set HotText to be true because automated hugify support
  52   // relies on it.
  53   opts::HotText = true;
  54   if (!BC.StartFunctionAddress) {
  55     errs() << "BOLT-ERROR: hugify runtime libraries require a known entry "
  56               "point of "
  57               "the input binary\n";
  58     exit(1);
  59   }
  60 }
  61
  62 void HugifyRuntimeLibrary::link(BinaryContext &BC, StringRef ToolPath,
  63                                 BOLTLinker &Linker,
  64                                 BOLTLinker::SectionsMapper MapSections) {
  65
  66   std::string LibPath = getLibPath(ToolPath, opts::RuntimeHugifyLib);
  67   loadLibrary(LibPath, Linker, MapSections);
  68
  69   assert(!RuntimeStartAddress &&
  70          "We don't currently support linking multiple runtime libraries");
  71   RuntimeStartAddress = Linker.lookupSymbol("__bolt_hugify_self").value_or(0);
  72   if (!RuntimeStartAddress) {
  73     errs() << "BOLT-ERROR: hugify library does not define __bolt_hugify_self: "
  74            << LibPath << "\n";
  75     exit(1);
  76   }
  77 }