90 lines
3.3 KiB
Plaintext
90 lines
3.3 KiB
Plaintext
- Add retguard for octeon/mips64.
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Index: lib/Target/Mips/MipsAsmPrinter.cpp
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--- lib/Target/Mips/MipsAsmPrinter.cpp.orig
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+++ lib/Target/Mips/MipsAsmPrinter.cpp
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@@ -242,6 +242,83 @@ void MipsAsmPrinter::emitInstruction(const MachineInst
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case Mips::PATCHABLE_TAIL_CALL:
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LowerPATCHABLE_TAIL_CALL(*MI);
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return;
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+ case Mips::RETGUARD_GET_FUNCTION_ADDR:
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+ {
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+ MCSymbol *PCSym = OutContext.createTempSymbol();
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+ MCSymbol *FuncSym = OutContext.lookupSymbol(MI->getMF()->getName());
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+ if (FuncSym == nullptr)
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+ llvm_unreachable("Function name has no symbol");
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+
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+ // Branch and link forward, calculate the distance
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+ // from here to the start of the function, and fill the
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+ // address in the given dest register
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+ unsigned OUT = MI->getOperand(0).getReg();
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+ unsigned IN1 = MI->getOperand(1).getReg();
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+ unsigned IN2 = MI->getOperand(2).getReg();
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+ MCSymbol *ReturnSym = MI->getOperand(3).getMCSymbol();
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+
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+ // Save the value of RA in IN1
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::OR64)
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+ .addReg(IN1)
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+ .addReg(Mips::RA_64)
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+ .addReg(Mips::ZERO_64));
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+ // BAL to get the PC into RA
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::BAL)
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+ .addExpr(MCSymbolRefExpr::create(ReturnSym, OutContext)));
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+ // NOP
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::SLL)
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+ .addReg(Mips::ZERO_64)
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+ .addReg(Mips::ZERO_64)
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+ .addImm(0));
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+
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+ // Emit a symbol for "here/PC" because BAL will put
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+ // the address of the instruction following the NOP into RA
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+ // and we need this symbol to do the math
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+ OutStreamer->emitLabel(PCSym);
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+
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+ // Store PC in IN2
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::OR64)
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+ .addReg(IN2)
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+ .addReg(Mips::RA_64)
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+ .addReg(Mips::ZERO_64));
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+ // Restore original RA
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::OR64)
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+ .addReg(Mips::RA_64)
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+ .addReg(IN1)
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+ .addReg(Mips::ZERO_64));
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+ // Load the offset from PCSym to the start of the function
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::LUi64)
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+ .addReg(IN1)
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+ .addExpr(MipsMCExpr::create(MipsMCExpr::MipsExprKind::MEK_HI,
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+ MCBinaryExpr::createSub(
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+ MCSymbolRefExpr::create(PCSym, OutContext),
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+ MCSymbolRefExpr::create(FuncSym, OutContext),
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+ OutContext),
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+ OutContext)));
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::DADDiu)
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+ .addReg(IN1)
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+ .addReg(IN1)
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+ .addExpr(MipsMCExpr::create(MipsMCExpr::MipsExprKind::MEK_LO,
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+ MCBinaryExpr::createSub(
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+ MCSymbolRefExpr::create(PCSym, OutContext),
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+ MCSymbolRefExpr::create(FuncSym, OutContext),
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+ OutContext),
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+ OutContext)));
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+
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+ // Sub distance from here to start of function
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+ // to get address of the start of function
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(Mips::DSUBu)
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+ .addReg(OUT)
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+ .addReg(IN2)
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+ .addReg(IN1));
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+ return;
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+ }
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+ case Mips::RETGUARD_EMIT_SYMBOL:
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+ {
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+ MCSymbol *ReturnSym = MI->getOperand(0).getMCSymbol();
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+ OutStreamer->emitLabel(ReturnSym);
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+ return;
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+ }
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}
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if (EmitJalrReloc &&
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