forked from OSchip/llvm-project
114 lines
4.1 KiB
C++
114 lines
4.1 KiB
C++
//===- bolt/RuntimeLibs/HugifyRuntimeLibrary.cpp - Hugify RT Library ------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the HugifyRuntimeLibrary class.
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//
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//===----------------------------------------------------------------------===//
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#include "bolt/RuntimeLibs/HugifyRuntimeLibrary.h"
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#include "bolt/Core/BinaryFunction.h"
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#include "llvm/ExecutionEngine/RuntimeDyld.h"
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#include "llvm/MC/MCStreamer.h"
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#include "llvm/Support/Alignment.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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using namespace bolt;
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namespace opts {
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extern cl::OptionCategory BoltOptCategory;
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extern cl::opt<bool> HotText;
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cl::opt<bool>
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Hugify("hugify",
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cl::desc("Automatically put hot code on 2MB page(s) (hugify) at "
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"runtime. No manual call to hugify is needed in the binary "
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"(which is what --hot-text relies on)."),
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cl::cat(BoltOptCategory));
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static cl::opt<std::string> RuntimeHugifyLib(
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"runtime-hugify-lib",
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cl::desc("specify file name of the runtime hugify library"),
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cl::init("libbolt_rt_hugify.a"), cl::cat(BoltOptCategory));
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} // namespace opts
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void HugifyRuntimeLibrary::adjustCommandLineOptions(
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const BinaryContext &BC) const {
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if (opts::HotText) {
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errs()
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<< "BOLT-ERROR: -hot-text should be applied to binaries with "
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"pre-compiled manual hugify support, while -hugify will add hugify "
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"support automatcally. These two options cannot both be present.\n";
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exit(1);
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}
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// After the check, we set HotText to be true because automated hugify support
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// relies on it.
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opts::HotText = true;
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if (!BC.StartFunctionAddress) {
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errs() << "BOLT-ERROR: hugify runtime libraries require a known entry "
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"point of "
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"the input binary\n";
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exit(1);
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}
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}
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void HugifyRuntimeLibrary::emitBinary(BinaryContext &BC, MCStreamer &Streamer) {
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const BinaryFunction *StartFunction =
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BC.getBinaryFunctionAtAddress(*(BC.StartFunctionAddress));
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assert(!StartFunction->isFragment() && "expected main function fragment");
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if (!StartFunction) {
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errs() << "BOLT-ERROR: failed to locate function at binary start address\n";
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exit(1);
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}
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const auto Flags = BinarySection::getFlags(/*IsReadOnly=*/false,
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/*IsText=*/false,
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/*IsAllocatable=*/true);
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MCSectionELF *Section =
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BC.Ctx->getELFSection(".bolt.hugify.entries", ELF::SHT_PROGBITS, Flags);
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// __bolt_hugify_init_ptr stores the poiter the hugify library needs to
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// jump to after finishing the init code.
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MCSymbol *InitPtr = BC.Ctx->getOrCreateSymbol("__bolt_hugify_init_ptr");
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Section->setAlignment(llvm::Align(BC.RegularPageSize));
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Streamer.switchSection(Section);
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Streamer.emitLabel(InitPtr);
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Streamer.emitSymbolAttribute(InitPtr, MCSymbolAttr::MCSA_Global);
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Streamer.emitValue(
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MCSymbolRefExpr::create(StartFunction->getSymbol(), *(BC.Ctx)),
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/*Size=*/8);
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}
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void HugifyRuntimeLibrary::link(BinaryContext &BC, StringRef ToolPath,
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RuntimeDyld &RTDyld,
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std::function<void(RuntimeDyld &)> OnLoad) {
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std::string LibPath = getLibPath(ToolPath, opts::RuntimeHugifyLib);
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loadLibrary(LibPath, RTDyld);
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OnLoad(RTDyld);
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RTDyld.finalizeWithMemoryManagerLocking();
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if (RTDyld.hasError()) {
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outs() << "BOLT-ERROR: RTDyld failed: " << RTDyld.getErrorString() << "\n";
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exit(1);
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}
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assert(!RuntimeStartAddress &&
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"We don't currently support linking multiple runtime libraries");
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RuntimeStartAddress = RTDyld.getSymbol("__bolt_hugify_self").getAddress();
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if (!RuntimeStartAddress) {
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errs() << "BOLT-ERROR: instrumentation library does not define "
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"__bolt_hugify_self: "
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<< LibPath << "\n";
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exit(1);
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}
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}
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