================
@@ -1805,15 +1777,141 @@ bool SystemZInstrInfo::expandPostRAPseudo(MachineInstr
&MI) const {
splitAdjDynAlloc(MI);
return true;
- case TargetOpcode::LOAD_STACK_GUARD:
- expandLoadStackGuard(&MI);
+ case SystemZ::MOVE_STACK_GUARD:
+ expandMSGPseudo(MI);
+ return true;
+
+ case SystemZ::COMPARE_STACK_GUARD:
+ expandCSGPseudo(MI);
return true;
default:
return false;
}
}
+namespace {
+Register scavengeAddrReg(MachineInstr &MI, MachineBasicBlock *MBB) {
+ // create fresh RegScavanger instance.
+ RegScavenger RS;
+ // initialize RegScavenger to correct location
+ RS.enterBasicBlockEnd(*MBB);
+ RS.backward(MI);
+
+ // Attempt to find a free register.
+ Register Scratch = RS.FindUnusedReg(&SystemZ::ADDR64BitRegClass);
+ // If not found, scavenge one, i.e. evict something to a stack spill slot.
+ if (!Scratch) {
+ Scratch =
+ RS.scavengeRegisterBackwards(SystemZ::ADDR64BitRegClass,
+ MI, // Scavenge back to this position.
+ true, // Scope must include MI.
+ 0,
+ true // Spills are allowed.
+ );
+ }
+ return Scratch;
+}
+unsigned long getStackGuardOffset(const MachineBasicBlock *MBB) {
+ // In the TLS (default) case, AddrReg will contain the thread pointer, so we
+ // need to add 40 bytes to get the actual address of the stack guard.
+ StringRef GuardType =
+ MBB->getParent()->getFunction().getParent()->getStackProtectorGuard();
+ return (GuardType == "global") ? 0 : 40;
+}
+// Check MI (which should be either MOVE_STACK_GUARD or COMPARE_STACK_GUARD)
+// to see if the early-clobber flag on the def reg was honored. If so,
+// return that register. If not, scavenge a new register and return that.
+// This is a workaround for https://github.com/llvm/llvm-project/issues/172511
+// and should be removed once that issue is resolved.
+Register chooseAddrReg(MachineInstr &MI, MachineBasicBlock *MBB) {
+ Register DefReg = MI.getOperand(0).getReg();
+ Register OpReg = MI.getOperand(1).getReg();
+ // if we can use DefReg, return it
+ if (DefReg != OpReg)
+ return DefReg;
+ // otherwise, scavenge
+ return scavengeAddrReg(MI, MBB);
+}
+} // namespace
+
+// Emit the stack guard address load, depending on guard type.
+// Return the register the stack guard address was loaded into.
+void SystemZInstrInfo::emitLoadStackGuardAddress(MachineInstr &MI,
+ Register AddrReg) const {
+ MachineBasicBlock &MBB = *(MI.getParent());
+ const MachineFunction &MF = *(MBB.getParent());
+ const MachineRegisterInfo &MRI = MF.getRegInfo();
+ const auto DL = MI.getDebugLoc();
+
+ const Module *M = MF.getFunction().getParent();
+ StringRef GuardType = M->getStackProtectorGuard();
+
+ if (GuardType.empty() || (GuardType == "tls")) {
+ // EAR can only load the low subregister so use a shift for %a0 to produce
+ // the GR containing %a0 and %a1.
+ const Register Reg32 =
+ MRI.getTargetRegisterInfo()->getSubReg(AddrReg, SystemZ::subreg_l32);
+
+ // ear <reg>, %a0
+ BuildMI(MBB, MI, DL, get(SystemZ::EAR), Reg32).addReg(SystemZ::A0);
+
+ // sllg <reg>, <reg>, 32
+ BuildMI(MBB, MI, DL, get(SystemZ::SLLG), AddrReg)
+ .addReg(AddrReg)
+ .addReg(0)
+ .addImm(32);
+
+ // ear <reg>, %a1
+ BuildMI(MBB, MI, DL, get(SystemZ::EAR), Reg32).addReg(SystemZ::A1);
+
+ } else if (GuardType == "global") {
+ // Obtain the global value.
+ const auto *GV = M->getNamedGlobal("__stack_chk_guard");
----------------
dominik-steenken wrote:
ok, via `getSDagStackGuard` i can directly get the global variable, and don't
need the name at all. I'll change that.
https://github.com/llvm/llvm-project/pull/169317
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