[PATCH] D127591: [X86] Emit .cfi_restore after popping callee-saved-registers if no red zone

[Sihoon Lee via Phabricator via llvm-commits]

silee created this revision.
silee added reviewers: craig.topper, thegameg.
Herald added subscribers: jsji, StephenFan, pengfei, hiraditya.
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We discovered the bug <https://github.com/llvm/llvm-project/issues/55993>
If the function has no red zone, cfi of the popped callee-saved-registers should be invalidated with .cfi_restore instruction.
This commit will emit .cfi_restore instruction after popping callee-saved-registers if no red zone.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D127591

Files:
  llvm/lib/Target/X86/X86FrameLowering.cpp


Index: llvm/lib/Target/X86/X86FrameLowering.cpp
===================================================================
--- llvm/lib/Target/X86/X86FrameLowering.cpp
+++ llvm/lib/Target/X86/X86FrameLowering.cpp
@@ -2166,6 +2166,9 @@
 void X86FrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
   const MachineFrameInfo &MFI = MF.getFrameInfo();
+  MachineModuleInfo &MMI = MF.getMMI();
+  const MCRegisterInfo *MRI = MMI.getContext().getRegisterInfo();
+  const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
   X86MachineFunctionInfo *X86FI = MF.getInfo<X86MachineFunctionInfo>();
   MachineBasicBlock::iterator Terminator = MBB.getFirstTerminator();
   MachineBasicBlock::iterator MBBI = Terminator;
@@ -2337,7 +2340,7 @@
   if (NeedsWin64CFI && MF.hasWinCFI())
     BuildMI(MBB, MBBI, DL, TII.get(X86::SEH_Epilogue));
 
-  if (!HasFP && NeedsDwarfCFI) {
+  if (NeedsDwarfCFI) {
     MBBI = FirstCSPop;
     int64_t Offset = -CSSize - SlotSize;
     // Mark callee-saved pop instruction.
@@ -2346,7 +2349,22 @@
       MachineBasicBlock::iterator PI = MBBI;
       unsigned Opc = PI->getOpcode();
       ++MBBI;
-      if (Opc == X86::POP32r || Opc == X86::POP64r) {
+      if (Opc == X86::POP32r || Opc == X86::POP64r)
+        continue;
+      if (!has128ByteRedZone(MF)) {
+        Register Reg = PI->getOperand(0).getReg();
+        // Check if the poped register is callee-saved register.
+        if (std::find_if(CSI.begin(), CSI.end(),
+                         [&Reg](const CalleeSavedInfo &I) -> bool {
+                           return Reg == I.getReg();
+                         }) != CSI.end()) {
+          unsigned DwarfReg = MRI->getDwarfRegNum(Reg, true);
+          BuildCFI(MBB, MBBI, DL,
+                   MCCFIInstruction::createRestore(nullptr, DwarfReg),
+                   MachineInstr::FrameDestroy);
+        }
+      }
+      if (!HasFP) {
         Offset += SlotSize;
         BuildCFI(MBB, MBBI, DL,
                  MCCFIInstruction::cfiDefCfaOffset(nullptr, -Offset),


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