[llvm] [AIX] Support per global code model. (PR #79202)

[via llvm-commits]

================
@@ -466,6 +466,63 @@ static void collectTOCStats(PPCAsmPrinter::TOCEntryType Type) {
   }
 }
 
+static CodeModel::Model getCodeModel(const PPCSubtarget &S,
+                                     const TargetMachine &TM,
+                                     const MachineOperand &MO) {
+  assert(S.isAIXABI() && "ELF per global code model not supported yet");
+
+  CodeModel::Model ModuleModel = TM.getCodeModel();
+
----------------
diggerlin wrote:

since the function are mostly used as 

```
const CodeModel::Model CM =
        IsAIX ? getCodeModel(*Subtarget, TM, MO) : TM.getCodeModel();
```
or 
```
if (IsAIX) {
      assert(
          getCodeModel(*Subtarget, TM, MO) == CodeModel::Small &&
          "This pseudo should only be selected for 32-bit small code model.");
 ```
 
 I would change  code to 
 ```
assert(S.isAIXABI() && "ELF per global code model not supported yet");

  CodeModel::Model ModuleModel = TM.getCodeModel();
```
 
 to
 ```
 CodeModel::Model ModuleModel = TM.getCodeModel();
  if(!S.isAIXABI())
     return ModuleModel;
```

https://github.com/llvm/llvm-project/pull/79202