[llvm-branch-commits] [lld] [lld][LoongArch] Convert TLS IE to LE in the normal or medium code model (PR #123680)

[Lu Weining via llvm-branch-commits]

================
@@ -1002,6 +1008,87 @@ static bool relax(Ctx &ctx, InputSection &sec) {
   return changed;
 }
 
+// Convert TLS IE to LE in the normal or medium code model.
+// Original code sequence:
+//  * pcalau12i $a0, %ie_pc_hi20(sym)
+//  * ld.d      $a0, $a0, %ie_pc_lo12(sym)
+//
+// The code sequence converted is as follows:
+//  * lu12i.w   $a0, %le_hi20(sym)  # le_hi20 != 0, otherwise NOP
+//  * ori $a0   $a0, %le_lo12(sym)
+//
+// When relaxation enables, redundant NOPs can be removed.
+void LoongArch::tlsIeToLe(uint8_t *loc, const Relocation &rel,
+                          uint64_t val) const {
+  assert(isInt<32>(val) &&
+         "val exceeds the range of medium code model in tlsIeToLe");
+
+  bool isUInt12 = isUInt<12>(val);
+  const uint32_t currInsn = read32le(loc);
+  switch (rel.type) {
+  case R_LARCH_TLS_IE_PC_HI20:
+    if (isUInt12)
+      write32le(loc, insn(ANDI, R_ZERO, R_ZERO, 0)); // nop
+    else
+      write32le(loc, insn(LU12I_W, getD5(currInsn), extractBits(val, 31, 12),
+                          0)); // lu12i.w $a0, %le_hi20
+    break;
+  case R_LARCH_TLS_IE_PC_LO12:
+    if (isUInt12)
+      write32le(loc, insn(ORI, getD5(currInsn), R_ZERO,
+                          val)); // ori $a0, $r0, %le_lo12
----------------
SixWeining wrote:

```suggestion
                          val)); // ori $a0, $zero, %le_lo12
```

https://github.com/llvm/llvm-project/pull/123680