[llvm] [bolt][aarch64] simplify rodata/literal load for X86 & AArch64 (PR #165723)

[Alexey Moksyakov via llvm-commits]

================
@@ -2797,6 +2797,56 @@ class AArch64MCPlusBuilder : public MCPlusBuilder {
     return Insts;
   }
 
+  InstructionListType materializeConstant(const MCInst &Inst,
+                                          StringRef ConstantData,
+                                          uint64_t Offset) const override {
+    struct InstInfo {
+      // Size in bytes that Inst loads from memory.
+      uint8_t DataSize;
+      // number instructions needed to materialize the constant.
+      uint8_t numInstrs;
+      // Opcode to use for materializing the constant.
+      unsigned Opcode;
+    };
+
+    InstInfo I;
+    InstructionListType Insts(0);
+    switch (Inst.getOpcode()) {
+    case AArch64::LDRWl:
+      I = {4, 2, AArch64::MOVKWi};
+      break;
+    case AArch64::LDRXl:
+      I = {8, 4, AArch64::MOVKXi};
+      break;
+    default:
+      llvm_unreachable("unexpected ldr instruction");
----------------
yavtuk wrote:

 we will be able to add extra logic as necessary

https://github.com/llvm/llvm-project/pull/165723