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usr / src / contrib / llvm-project / llvm / lib / Target / X86 /

📁 ..
📁 AsmParser
📁 Disassembler
📄 ImmutableGraph.h(15.15 KB)
📁 MCTargetDesc
📁 TargetInfo
📄 X86.h(7.41 KB)
📄 X86.td(68.44 KB)
📄 X86AsmPrinter.cpp(27.18 KB)
📄 X86AsmPrinter.h(5.96 KB)
📄 X86AvoidStoreForwardingBlocks.cpp(27.94 KB)
📄 X86AvoidTrailingCall.cpp(4.91 KB)
📄 X86CallFrameOptimization.cpp(23.07 KB)
📄 X86CallLowering.cpp(17.62 KB)
📄 X86CallLowering.h(1.74 KB)
📄 X86CallingConv.cpp(13.34 KB)
📄 X86CallingConv.h(1.09 KB)
📄 X86CallingConv.td(46.15 KB)
📄 X86CmovConversion.cpp(34.07 KB)
📄 X86CondBrFolding.cpp(18.4 KB)
📄 X86DiscriminateMemOps.cpp(7.11 KB)
📄 X86DomainReassignment.cpp(25.87 KB)
📄 X86EvexToVex.cpp(8.8 KB)
📄 X86ExpandPseudo.cpp(16.95 KB)
📄 X86FastISel.cpp(139.28 KB)
📄 X86FixupBWInsts.cpp(18.09 KB)
📄 X86FixupLEAs.cpp(24.44 KB)
📄 X86FixupSetCC.cpp(4.44 KB)
📄 X86FlagsCopyLowering.cpp(40.36 KB)
📄 X86FloatingPoint.cpp(62.66 KB)
📄 X86FrameLowering.cpp(138.71 KB)
📄 X86FrameLowering.h(11.64 KB)
📄 X86GenRegisterBankInfo.def(3.32 KB)
📄 X86ISelDAGToDAG.cpp(208.37 KB)
📄 X86ISelLowering.cpp(1.94 MB)
📄 X86ISelLowering.h(60.88 KB)
📄 X86IndirectBranchTracking.cpp(6.17 KB)
📄 X86IndirectThunks.cpp(9.78 KB)
📄 X86InsertPrefetch.cpp(9.64 KB)
📄 X86InsertWait.cpp(4.47 KB)
📄 X86Instr3DNow.td(5.24 KB)
📄 X86InstrAMX.td(5.6 KB)
📄 X86InstrAVX512.td(653.76 KB)
📄 X86InstrArithmetic.td(75.61 KB)
📄 X86InstrBuilder.h(8.45 KB)
📄 X86InstrCMovSetCC.td(5.76 KB)
📄 X86InstrCompiler.td(95.78 KB)
📄 X86InstrControl.td(20.53 KB)
📄 X86InstrExtension.td(11.64 KB)
📄 X86InstrFMA.td(33.23 KB)
📄 X86InstrFMA3Info.cpp(6.21 KB)
📄 X86InstrFMA3Info.h(3.25 KB)
📄 X86InstrFPStack.td(39.52 KB)
📄 X86InstrFoldTables.cpp(393.01 KB)
📄 X86InstrFoldTables.h(3.03 KB)
📄 X86InstrFormats.td(41.05 KB)
📄 X86InstrFragmentsSIMD.td(61.14 KB)
📄 X86InstrInfo.cpp(322.72 KB)
📄 X86InstrInfo.h(29.34 KB)
📄 X86InstrInfo.td(169.76 KB)
📄 X86InstrMMX.td(29.55 KB)
📄 X86InstrMPX.td(3.63 KB)
📄 X86InstrSGX.td(1.12 KB)
📄 X86InstrSSE.td(385.01 KB)
📄 X86InstrSVM.td(2.16 KB)
📄 X86InstrShiftRotate.td(49.56 KB)
📄 X86InstrSystem.td(34.03 KB)
📄 X86InstrTSX.td(2.1 KB)
📄 X86InstrVMX.td(3.53 KB)
📄 X86InstrVecCompiler.td(21.09 KB)
📄 X86InstrXOP.td(23.81 KB)
📄 X86InstructionSelector.cpp(61.11 KB)
📄 X86InterleavedAccess.cpp(32.7 KB)
📄 X86IntrinsicsInfo.h(73.96 KB)
📄 X86LegalizerInfo.cpp(15.6 KB)
📄 X86LegalizerInfo.h(1.65 KB)
📄 X86LoadValueInjectionLoadHardening.cpp(32.4 KB)
📄 X86LoadValueInjectionRetHardening.cpp(4.93 KB)
📄 X86MCInstLower.cpp(96.53 KB)
📄 X86MachineFunctionInfo.cpp(1.1 KB)
📄 X86MachineFunctionInfo.h(8.87 KB)
📄 X86MacroFusion.cpp(2.62 KB)
📄 X86MacroFusion.h(992 B)
📄 X86OptimizeLEAs.cpp(27.47 KB)
📄 X86PadShortFunction.cpp(7.33 KB)
📄 X86PartialReduction.cpp(15.46 KB)
📄 X86PfmCounters.td(10.18 KB)
📄 X86RegisterBankInfo.cpp(10.55 KB)
📄 X86RegisterBankInfo.h(2.87 KB)
📄 X86RegisterBanks.td(629 B)
📄 X86RegisterInfo.cpp(29 KB)
📄 X86RegisterInfo.h(5.61 KB)
📄 X86RegisterInfo.td(26.07 KB)
📄 X86SchedBroadwell.td(69.45 KB)
📄 X86SchedHaswell.td(73.96 KB)
📄 X86SchedPredicates.td(4.23 KB)
📄 X86SchedSandyBridge.td(50 KB)
📄 X86SchedSkylakeClient.td(74.65 KB)
📄 X86SchedSkylakeServer.td(113.85 KB)
📄 X86Schedule.td(36.9 KB)
📄 X86ScheduleAtom.td(38.26 KB)
📄 X86ScheduleBdVer2.td(56.78 KB)
📄 X86ScheduleBtVer2.td(46.98 KB)
📄 X86ScheduleSLM.td(22.91 KB)
📄 X86ScheduleZnver1.td(48.97 KB)
📄 X86ScheduleZnver2.td(48.12 KB)
📄 X86SelectionDAGInfo.cpp(12.02 KB)
📄 X86SelectionDAGInfo.h(1.8 KB)
📄 X86ShuffleDecodeConstantPool.cpp(11.22 KB)
📄 X86ShuffleDecodeConstantPool.h(2.13 KB)
📄 X86SpeculativeExecutionSideEffectSuppression.cpp(6.97 KB)
📄 X86SpeculativeLoadHardening.cpp(93.16 KB)
📄 X86Subtarget.cpp(13.25 KB)
📄 X86Subtarget.h(32.08 KB)
📄 X86TargetMachine.cpp(18.88 KB)
📄 X86TargetMachine.h(2.04 KB)
📄 X86TargetObjectFile.cpp(2.61 KB)
📄 X86TargetObjectFile.h(2.13 KB)
📄 X86TargetTransformInfo.cpp(189.14 KB)
📄 X86TargetTransformInfo.h(9.63 KB)
📄 X86VZeroUpper.cpp(12.59 KB)
📄 X86WinAllocaExpander.cpp(9.54 KB)
📄 X86WinEHState.cpp(28.97 KB)

Editing: X86AvoidTrailingCall.cpp

//===----- X86AvoidTrailingCall.cpp - Insert int3 after trailing calls ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// The Windows x64 unwinder decodes the instruction stream during unwinding.
// The unwinder decodes forward from the current PC to detect epilogue code
// patterns.
//
// First, this means that there must be an instruction after every
// call instruction for the unwinder to decode. LLVM must maintain the invariant
// that the last instruction of a function or funclet is not a call, or the
// unwinder may decode into the next function. Similarly, a call may not
// immediately precede an epilogue code pattern. As of this writing, the
// SEH_Epilogue pseudo instruction takes care of that.
//
// Second, all non-tail call jump targets must be within the *half-open*
// interval of the bounds of the function. The unwinder distinguishes between
// internal jump instructions and tail calls in an epilogue sequence by checking
// the jump target against the function bounds from the .pdata section. This
// means that the last regular MBB of an LLVM function must not be empty if
// there are regular jumps targeting it.
//
// This pass upholds these invariants by ensuring that blocks at the end of a
// function or funclet are a) not empty and b) do not end in a CALL instruction.
//
// Unwinder implementation for reference:
// https://github.com/dotnet/coreclr/blob/a9f3fc16483eecfc47fb79c362811d870be02249/src/unwinder/amd64/unwinder_amd64.cpp#L1015
//
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"

#define AVOIDCALL_DESC "X86 avoid trailing call pass"
#define AVOIDCALL_NAME "x86-avoid-trailing-call"

#define DEBUG_TYPE AVOIDCALL_NAME

using namespace llvm;

namespace {
class X86AvoidTrailingCallPass : public MachineFunctionPass {
public:
  X86AvoidTrailingCallPass() : MachineFunctionPass(ID) {}

bool runOnMachineFunction(MachineFunction &MF) override;

static char ID;

private:
  StringRef getPassName() const override { return AVOIDCALL_DESC; }
};
} // end anonymous namespace

char X86AvoidTrailingCallPass::ID = 0;

FunctionPass *llvm::createX86AvoidTrailingCallPass() {
  return new X86AvoidTrailingCallPass();
}

INITIALIZE_PASS(X86AvoidTrailingCallPass, AVOIDCALL_NAME, AVOIDCALL_DESC, false, false)

// A real instruction is a non-meta, non-pseudo instruction.  Some pseudos
// expand to nothing, and some expand to code. This logic conservatively assumes
// they might expand to nothing.
static bool isRealInstruction(MachineInstr &MI) {
  return !MI.isPseudo() && !MI.isMetaInstruction();
}

// Return true if this is a call instruction, but not a tail call.
static bool isCallInstruction(const MachineInstr &MI) {
  return MI.isCall() && !MI.isReturn();
}

bool X86AvoidTrailingCallPass::runOnMachineFunction(MachineFunction &MF) {
  const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
  const X86InstrInfo &TII = *STI.getInstrInfo();
  assert(STI.isTargetWin64() && "pass only runs on Win64");

// We don't need to worry about any of the invariants described above if there
  // is no unwind info (CFI).
  if (!MF.hasWinCFI())
    return false;

// FIXME: Perhaps this pass should also replace SEH_Epilogue by inserting nops
  // before epilogues.

bool Changed = false;
  for (MachineBasicBlock &MBB : MF) {
    // Look for basic blocks that precede funclet entries or are at the end of
    // the function.
    MachineBasicBlock *NextMBB = MBB.getNextNode();
    if (NextMBB && !NextMBB->isEHFuncletEntry())
      continue;

// Find the last real instruction in this block.
    auto LastRealInstr = llvm::find_if(reverse(MBB), isRealInstruction);

// If the block is empty or the last real instruction is a call instruction,
    // insert an int3. If there is a call instruction, insert the int3 between
    // the call and any labels or other meta instructions. If the block is
    // empty, insert at block end.
    bool IsEmpty = LastRealInstr == MBB.rend();
    bool IsCall = !IsEmpty && isCallInstruction(*LastRealInstr);
    if (IsEmpty || IsCall) {
      LLVM_DEBUG({
        if (IsCall) {
          dbgs() << "inserting int3 after trailing call instruction:\n";
          LastRealInstr->dump();
          dbgs() << '\n';
        } else {
          dbgs() << "inserting int3 in trailing empty MBB:\n";
          MBB.dump();
        }
      });

MachineBasicBlock::iterator MBBI = MBB.end();
      DebugLoc DL;
      if (IsCall) {
        MBBI = std::next(LastRealInstr.getReverse());
        DL = LastRealInstr->getDebugLoc();
      }
      BuildMI(MBB, MBBI, DL, TII.get(X86::INT3));
      Changed = true;
    }
  }

return Changed;
}

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Editing: X86AvoidTrailingCall.cpp

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