d55dfeaf32
As we are moving towards support for multiple fragments, loops that iterate over all basic blocks of a function, but do not depend on the order of basic blocks in the final layout, should iterate over binary functions directly, rather than the layout. Eventually, all loops using the layout list should either iterate over the function, or be aware of multiple layouts. This patch replaces references to binary function's block layout with the binary function itself where only little code changes are necessary. Reviewed By: maksfb Differential Revision: https://reviews.llvm.org/D129585
90 lines
2.5 KiB
C++
90 lines
2.5 KiB
C++
//===- bolt/Passes/PLTCall.h - PLT call optimization ----------------------===//
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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 PLTCall class, which replaces calls to PLT entries
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// with indirect calls against GOT.
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//
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//===----------------------------------------------------------------------===//
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#include "bolt/Passes/PLTCall.h"
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#include "llvm/Support/CommandLine.h"
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#define DEBUG_TYPE "bolt-plt"
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using namespace llvm;
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namespace opts {
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extern cl::OptionCategory BoltOptCategory;
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cl::opt<bolt::PLTCall::OptType>
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PLT("plt",
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cl::desc("optimize PLT calls (requires linking with -znow)"),
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cl::init(bolt::PLTCall::OT_NONE),
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cl::values(clEnumValN(bolt::PLTCall::OT_NONE,
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"none",
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"do not optimize PLT calls"),
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clEnumValN(bolt::PLTCall::OT_HOT,
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"hot",
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"optimize executed (hot) PLT calls"),
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clEnumValN(bolt::PLTCall::OT_ALL,
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"all",
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"optimize all PLT calls")),
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cl::ZeroOrMore,
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cl::cat(BoltOptCategory));
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}
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namespace llvm {
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namespace bolt {
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void PLTCall::runOnFunctions(BinaryContext &BC) {
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if (opts::PLT == OT_NONE)
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return;
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uint64_t NumCallsOptimized = 0;
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for (auto &It : BC.getBinaryFunctions()) {
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BinaryFunction &Function = It.second;
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if (!shouldOptimize(Function))
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continue;
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if (opts::PLT == OT_HOT &&
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Function.getExecutionCount() == BinaryFunction::COUNT_NO_PROFILE)
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continue;
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for (BinaryBasicBlock &BB : Function) {
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if (opts::PLT == OT_HOT && !BB.getKnownExecutionCount())
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continue;
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for (MCInst &Instr : BB) {
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if (!BC.MIB->isCall(Instr))
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continue;
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const MCSymbol *CallSymbol = BC.MIB->getTargetSymbol(Instr);
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if (!CallSymbol)
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continue;
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const BinaryFunction *CalleeBF = BC.getFunctionForSymbol(CallSymbol);
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if (!CalleeBF || !CalleeBF->isPLTFunction())
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continue;
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BC.MIB->convertCallToIndirectCall(Instr, CalleeBF->getPLTSymbol(),
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BC.Ctx.get());
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BC.MIB->addAnnotation(Instr, "PLTCall", true);
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++NumCallsOptimized;
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}
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}
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}
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if (NumCallsOptimized) {
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BC.RequiresZNow = true;
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outs() << "BOLT-INFO: " << NumCallsOptimized
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<< " PLT calls in the binary were optimized.\n";
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}
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}
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} // namespace bolt
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} // namespace llvm
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