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2d9650b5d9
Emit error when BPF backend sees a call to a global function or to an external symbol. The kernel verifier only allows calls to predefined helpers from bpf.h which are defined in 'enum bpf_func_id'. Such calls in assembler must look like 'call [1-9]+' where number matches bpf_func_id. Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 292204
85 lines
2.6 KiB
C++
85 lines
2.6 KiB
C++
//=-- BPFMCInstLower.cpp - Convert BPF MachineInstr to an MCInst ------------=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains code to lower BPF MachineInstrs to their corresponding
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// MCInst records.
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//
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//===----------------------------------------------------------------------===//
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#include "BPFMCInstLower.h"
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#include "llvm/CodeGen/AsmPrinter.h"
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#include "llvm/CodeGen/MachineBasicBlock.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCInst.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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MCSymbol *
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BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
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return Printer.getSymbol(MO.getGlobal());
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}
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MCSymbol *
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BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
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return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
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}
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MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
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MCSymbol *Sym) const {
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const MCExpr *Expr = MCSymbolRefExpr::create(Sym, Ctx);
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if (!MO.isJTI() && MO.getOffset())
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llvm_unreachable("unknown symbol op");
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return MCOperand::createExpr(Expr);
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}
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void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
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OutMI.setOpcode(MI->getOpcode());
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for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
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const MachineOperand &MO = MI->getOperand(i);
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MCOperand MCOp;
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switch (MO.getType()) {
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default:
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MI->dump();
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llvm_unreachable("unknown operand type");
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case MachineOperand::MO_Register:
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// Ignore all implicit register operands.
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if (MO.isImplicit())
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continue;
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MCOp = MCOperand::createReg(MO.getReg());
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break;
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case MachineOperand::MO_Immediate:
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MCOp = MCOperand::createImm(MO.getImm());
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break;
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case MachineOperand::MO_MachineBasicBlock:
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MCOp = MCOperand::createExpr(
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MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), Ctx));
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break;
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case MachineOperand::MO_RegisterMask:
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continue;
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case MachineOperand::MO_ExternalSymbol:
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MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
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break;
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case MachineOperand::MO_GlobalAddress:
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MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
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break;
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}
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OutMI.addOperand(MCOp);
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}
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}
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