[lld] [ELF] Support R_RISCV_SET_ULEB128/R_RISCV_SUB_ULEB128 in SHF_ALLOC sections (PR #77261)

[Fangrui Song via llvm-commits]

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@@ -515,6 +517,46 @@ void RISCV::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
   }
 }
 
+void RISCV::relocateAlloc(InputSectionBase &sec, uint8_t *buf) const {
+  uint64_t secAddr = sec.getOutputSection()->addr;
+  if (auto *s = dyn_cast<InputSection>(&sec))
+    secAddr += s->outSecOff;
+  else if (auto *ehIn = dyn_cast<EhInputSection>(&sec))
+    secAddr += ehIn->getParent()->outSecOff;
+  for (size_t i = 0, size = sec.relocs().size(); i != size; ++i) {
+    const Relocation &rel = sec.relocs()[i];
+    uint8_t *loc = buf + rel.offset;
+    const uint64_t val =
+        sec.getRelocTargetVA(sec.file, rel.type, rel.addend,
+                             secAddr + rel.offset, *rel.sym, rel.expr);
+
+    switch (rel.expr) {
+    case R_RELAX_HINT:
+      break;
+    case R_RISCV_LEB128:
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MaskRay wrote:

I'll merge this soon. `relocateAlloc` is needed for TLSDESC relaxation as well.

https://github.com/llvm/llvm-project/pull/77261