[llvm] [PowerPC] Support local-dynamic TLS relocation on AIX (PR #66316)

[Kai Luo via llvm-commits]

================
@@ -145,19 +158,57 @@ namespace {
                                                               .addImm(0);
 
         if (IsAIX) {
-          // The variable offset and region handle are copied in r4 and r3. The
-          // copies are followed by GETtlsADDR32AIX/GETtlsADDR64AIX.
-          if (!IsTLSTPRelMI) {
-            BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), GPR4)
-                .addReg(MI.getOperand(1).getReg());
+          if (MI.getOpcode() == PPC::TLSLDAIX8 ||
+              MI.getOpcode() == PPC::TLSLDAIX) {
+            // For Local-Dynamic, the module handle is copied in r3. The copy is
+            // followed by GETtlsMOD32AIX/GETtlsMOD64AIX.
+            const PPCSubtarget &Subtarget =
+                MBB.getParent()->getSubtarget<PPCSubtarget>();
+            bool IsLargeModel =
+                Subtarget.getTargetMachine().getCodeModel() == CodeModel::Large;
+            Register ModuleHandleHReg;
+            unsigned LDTocOp =
+                Is64Bit ? (IsLargeModel ? PPC::LDtocL : PPC::LDtoc)
+                        : (IsLargeModel ? PPC::LWZtocL : PPC::LWZtoc);
+            if (IsLargeModel) {
+              ModuleHandleHReg = RegInfo.createVirtualRegister(GPRNoZero);
+              BuildMI(MBB, I, DL,
+                      TII->get(Is64Bit ? PPC::ADDIStocHA8 : PPC::ADDIStocHA),
+                      ModuleHandleHReg)
+                  .addReg(Subtarget.getTOCPointerRegister())
+                  .addExternalSymbol("_$TLSML[TC]", PPCII::MO_TLSLD_FLAG);
+            }
+            Register MHReg = RegInfo.createVirtualRegister(GPRNoZero);
+            BuildMI(MBB, I, DL, TII->get(LDTocOp), MHReg)
+                .addExternalSymbol("_$TLSML[TC]", PPCII::MO_TLSLD_FLAG)
+                .addReg(IsLargeModel
+                            ? ModuleHandleHReg
+                            : Register(Subtarget.getTOCPointerRegister()));
             BuildMI(MBB, I, DL, TII->get(TargetOpcode::COPY), GPR3)
-                .addReg(MI.getOperand(2).getReg());
-            BuildMI(MBB, I, DL, TII->get(Opc2), GPR3).addReg(GPR3).addReg(GPR4);
-          } else
-            // The opcode of GETtlsTpointer32AIX does not change, because later
-            // this instruction will be expanded into a call to .__get_tpointer,
-            // which will return the thread pointer into r3.
-            BuildMI(MBB, I, DL, TII->get(Opc2), GPR3);
+                .addReg(MHReg);
+            // The call to __tls_get_mod.
----------------
bzEq wrote:

```suggestion
            // The call to .__tls_get_mod.
```

https://github.com/llvm/llvm-project/pull/66316