[clang] [llvm] [SystemZ] Global Stackprotector and associated location section (PR #169317)

[Ulrich Weigand via cfe-commits]

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@@ -741,13 +743,41 @@ void SystemZAsmPrinter::emitInstruction(const MachineInstr *MI) {
   case SystemZ::EH_SjLj_Setup:
     return;
 
+  case SystemZ::LOAD_STACK_GUARD:
+    llvm_unreachable(
+        "LOAD_STACK_GUARD should have been eliminated by the DAG Combiner.");
+
+  case SystemZ::MOVE_STACK_GUARD:
+  case SystemZ::COMPARE_STACK_GUARD:
+    llvm_unreachable("MOVE_STACK_GUARD and COMPARE_STACK_GUARD should have "
+                     "been expanded by ExpandPostRAPseudo.");
+
+  case SystemZ::LARL:
+  case SystemZ::LGRL: {
+    auto &Op = MI->getOperand(1);
+    if (Op.isGlobal() && (Op.getGlobal()->getName() == "__stack_chk_guard"))
----------------
uweigand wrote:

I do not like this.  We should not test against particular symbol names.  (The symbol name shouldn't be hard-coded in the first place.)  [ Also, LARL and LGRL are very common operations, so this may also be a bit of a compile-time hit. ]

If we have to emit the loc entry at asm-printer time (and that's likely true), we should be using some *other* MI opcode here, and translate them to LARL / LGRL here.  [ Might be one or two opcodes.  ]

https://github.com/llvm/llvm-project/pull/169317