bolt/lib/Passes/Hugify.cpp

   1 //===--- bolt/Passes/Hugify.cpp -------------------------------------------===//
   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 #include "bolt/Passes/Hugify.h"
  10 #include "llvm/Support/CommandLine.h"
  11
  12 #define DEBUG_TYPE "bolt-hugify"
  13
  14 using namespace llvm;
  15
  16 namespace llvm {
  17 namespace bolt {
  18
  19 void HugePage::runOnFunctions(BinaryContext &BC) {
  20   auto *RtLibrary = BC.getRuntimeLibrary();
  21   if (!RtLibrary || !BC.isELF() || !BC.StartFunctionAddress) {
  22     return;
  23   }
  24
  25   auto createSimpleFunction =
  26       [&](std::string Title, std::vector<MCInst> Instrs) -> BinaryFunction * {
  27     BinaryFunction *Func = BC.createInjectedBinaryFunction(Title);
  28
  29     std::vector<std::unique_ptr<BinaryBasicBlock>> BBs;
  30     BBs.emplace_back(Func->createBasicBlock(nullptr));
  31     BBs.back()->addInstructions(Instrs.begin(), Instrs.end());
  32     BBs.back()->setCFIState(0);
  33     BBs.back()->setOffset(BinaryBasicBlock::INVALID_OFFSET);
  34
  35     Func->insertBasicBlocks(nullptr, std::move(BBs),
  36                             /*UpdateLayout=*/true,
  37                             /*UpdateCFIState=*/false);
  38     Func->updateState(BinaryFunction::State::CFG_Finalized);
  39     return Func;
  40   };
  41
  42   const BinaryFunction *const Start =
  43       BC.getBinaryFunctionAtAddress(*BC.StartFunctionAddress);
  44   assert(Start && "Entry point function not found");
  45   const MCSymbol *StartSym = Start->getSymbol();
  46   createSimpleFunction("__bolt_hugify_start_program",
  47                        BC.MIB->createSymbolTrampoline(StartSym, BC.Ctx.get()));
  48 }
  49 } // namespace bolt
  50 } // namespace llvm