634e5c9204
add PowerPC Secure PLT support and enable Secure PLT by default for OpenBSD. from Brad (maintainer)
101 lines
4.3 KiB
Plaintext
101 lines
4.3 KiB
Plaintext
$OpenBSD: patch-lib_Target_PowerPC_PPCAsmPrinter_cpp,v 1.4 2018/11/17 08:32:38 ajacoutot Exp $
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[PowerPC] Secure PLT support
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Index: lib/Target/PowerPC/PPCAsmPrinter.cpp
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--- lib/Target/PowerPC/PPCAsmPrinter.cpp.orig
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+++ lib/Target/PowerPC/PPCAsmPrinter.cpp
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@@ -563,33 +563,59 @@ void PPCAsmPrinter::EmitInstruction(const MachineInstr
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// Transform %rd = UpdateGBR(%rt, %ri)
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// Into: lwz %rt, .L0$poff - .L0$pb(%ri)
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// add %rd, %rt, %ri
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+ // or into (if secure plt mode is on):
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+ // addis r30, r30, .LTOC - .L0$pb@ha
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+ // addi r30, r30, .LTOC - .L0$pb@l
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// Get the offset from the GOT Base Register to the GOT
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LowerPPCMachineInstrToMCInst(MI, TmpInst, *this, isDarwin);
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- MCSymbol *PICOffset =
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- MF->getInfo<PPCFunctionInfo>()->getPICOffsetSymbol();
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- TmpInst.setOpcode(PPC::LWZ);
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- const MCExpr *Exp =
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- MCSymbolRefExpr::create(PICOffset, MCSymbolRefExpr::VK_None, OutContext);
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- const MCExpr *PB =
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- MCSymbolRefExpr::create(MF->getPICBaseSymbol(),
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- MCSymbolRefExpr::VK_None,
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- OutContext);
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- const MCOperand TR = TmpInst.getOperand(1);
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- const MCOperand PICR = TmpInst.getOperand(0);
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+ if (Subtarget->isSecurePlt() && isPositionIndependent() ) {
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+ unsigned PICR = TmpInst.getOperand(0).getReg();
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+ MCSymbol *LTOCSymbol = OutContext.getOrCreateSymbol(StringRef(".LTOC"));
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+ const MCExpr *PB =
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+ MCSymbolRefExpr::create(MF->getPICBaseSymbol(),
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+ OutContext);
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- // Step 1: lwz %rt, .L$poff - .L$pb(%ri)
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- TmpInst.getOperand(1) =
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- MCOperand::createExpr(MCBinaryExpr::createSub(Exp, PB, OutContext));
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- TmpInst.getOperand(0) = TR;
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- TmpInst.getOperand(2) = PICR;
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- EmitToStreamer(*OutStreamer, TmpInst);
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-
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- TmpInst.setOpcode(PPC::ADD4);
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- TmpInst.getOperand(0) = PICR;
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- TmpInst.getOperand(1) = TR;
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- TmpInst.getOperand(2) = PICR;
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- EmitToStreamer(*OutStreamer, TmpInst);
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- return;
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+ const MCExpr *LTOCDeltaExpr =
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+ MCBinaryExpr::createSub(MCSymbolRefExpr::create(LTOCSymbol, OutContext),
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+ PB, OutContext);
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+ const MCExpr *LTOCDeltaHi =
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+ PPCMCExpr::createHa(LTOCDeltaExpr, false, OutContext);
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDIS)
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+ .addReg(PICR)
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+ .addReg(PICR)
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+ .addExpr(LTOCDeltaHi));
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+ const MCExpr *LTOCDeltaLo =
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+ PPCMCExpr::createLo(LTOCDeltaExpr, false, OutContext);
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+ EmitToStreamer(*OutStreamer, MCInstBuilder(PPC::ADDI)
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+ .addReg(PICR)
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+ .addReg(PICR)
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+ .addExpr(LTOCDeltaLo));
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+ return;
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+ } else {
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+ MCSymbol *PICOffset =
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+ MF->getInfo<PPCFunctionInfo>()->getPICOffsetSymbol();
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+ TmpInst.setOpcode(PPC::LWZ);
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+ const MCExpr *Exp =
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+ MCSymbolRefExpr::create(PICOffset, MCSymbolRefExpr::VK_None, OutContext);
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+ const MCExpr *PB =
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+ MCSymbolRefExpr::create(MF->getPICBaseSymbol(),
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+ MCSymbolRefExpr::VK_None,
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+ OutContext);
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+ const MCOperand TR = TmpInst.getOperand(1);
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+ const MCOperand PICR = TmpInst.getOperand(0);
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+ // Step 1: lwz %rt, .L$poff - .L$pb(%ri)
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+ TmpInst.getOperand(1) =
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+ MCOperand::createExpr(MCBinaryExpr::createSub(Exp, PB, OutContext));
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+ TmpInst.getOperand(0) = TR;
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+ TmpInst.getOperand(2) = PICR;
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+ EmitToStreamer(*OutStreamer, TmpInst);
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+ TmpInst.setOpcode(PPC::ADD4);
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+ TmpInst.getOperand(0) = PICR;
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+ TmpInst.getOperand(1) = TR;
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+ TmpInst.getOperand(2) = PICR;
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+ EmitToStreamer(*OutStreamer, TmpInst);
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+ return;
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+ }
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}
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case PPC::LWZtoc: {
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// Transform %r3 = LWZtoc @min1, %r2
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@@ -1233,7 +1259,7 @@ void PPCLinuxAsmPrinter::EmitFunctionEntryLabel() {
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if (!Subtarget->isPPC64()) {
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const PPCFunctionInfo *PPCFI = MF->getInfo<PPCFunctionInfo>();
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- if (PPCFI->usesPICBase()) {
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+ if (PPCFI->usesPICBase() && !Subtarget->isSecurePlt()) {
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MCSymbol *RelocSymbol = PPCFI->getPICOffsetSymbol();
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MCSymbol *PICBase = MF->getPICBaseSymbol();
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OutStreamer->EmitLabel(RelocSymbol);
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