[CodeGen][LLVM] Fix MachineOperand::print crash when TII is nullptr.

[fanfuqiang]

This crash will caused if run this testcase:
llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ds.gws.barrier-fastregalloc.ll

When build the SDNode, precisely build the SDNode for this ir:

  call void @llvm.amdgcn.ds.gws.barrier(i32 %val, i32 0)

If want call the dump function of the new SDNode in the gdb environment like this:

  p N->dump()

The llvm will crash.

All of these is because calling dump() will cause the callingMachineMemOperand::print()
with the argument value for theTII is nullptr.
And the llvm/lib/CodeGen/MachineOperand.cpp#L1235 is a derefrence of TII.

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: z (fanfuqiang)

Changes

This crash will caused if run this testcase:
llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ds.gws.barrier-fastregalloc.ll

When build the SDNode, precisely build the SDNode for this ir:

  call void @<!-- -->llvm.amdgcn.ds.gws.barrier(i32 %val, i32 0)

If want call the dump function of the new SDNode in the gdb environment like this:

  p N->dump()

The llvm will crash.

All of these is because calling dump() will cause the callingMachineMemOperand::print()
with the argument value for theTII is nullptr.
And the llvm/lib/CodeGen/MachineOperand.cpp#L1235 is a derefrence of TII.

---

Full diff: https://github.com/llvm/llvm-project/pull/135170.diff

1 Files Affected:

• (modified) llvm/lib/CodeGen/MachineOperand.cpp (+6-2)

diff --git a/llvm/lib/CodeGen/MachineOperand.cpp b/llvm/lib/CodeGen/MachineOperand.cpp
index 231d66607b700..0d251697f2567 100644
--- a/llvm/lib/CodeGen/MachineOperand.cpp
+++ b/llvm/lib/CodeGen/MachineOperand.cpp
@@ -1232,13 +1232,17 @@ void MachineMemOperand::print(raw_ostream &OS, ModuleSlotTracker &MST,
           OS, cast<ExternalSymbolPseudoSourceValue>(PVal)->getSymbol());
       break;
     default: {
-      const MIRFormatter *Formatter = TII->getMIRFormatter();
       // FIXME: This is not necessarily the correct MIR serialization format for
       // a custom pseudo source value, but at least it allows
       // MIR printing to work on a target with custom pseudo source
       // values.
       OS << "custom \"";
-      Formatter->printCustomPseudoSourceValue(OS, MST, *PVal);
+      if (TII) {
+        const MIRFormatter *Formatter = TII->getMIRFormatter();
+        Formatter->printCustomPseudoSourceValue(OS, MST, *PVal);
+      } else {
+        PVal->printCustom(OS);
+      }
       OS << '\"';
       break;
     }

[fanfuqiang]

Run the testcase: llvm/test/CodeGen/AMDGPU/llvm.amdgcn.ds.gws.barrier-fastregalloc.ll
The callstack catch the crash: