[lld] Migrate away from PointerUnion::dyn_cast (NFC)

[kazutakahirata]

Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:

// FIXME: Replace the uses of is(), get() and dyn_cast() with
// isa, cast and the llvm::dyn_cast

Literal migration would result in dyn_cast_if_present (see the
definition of PointerUnion::dyn_cast), but this patch uses cast
because we know expect isa<Symbol *>(rel.referent) to be true.

[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-macho

Author: Kazu Hirata (kazutakahirata)

Changes

Note that PointerUnion::dyn_cast has been soft deprecated in
PointerUnion.h:

// FIXME: Replace the uses of is(), get() and dyn_cast() with
// isa<T>, cast<T> and the llvm::dyn_cast<T>

Literal migration would result in dyn_cast_if_present (see the
definition of PointerUnion::dyn_cast), but this patch uses cast
because we know expect isa<Symbol *>(rel.referent) to be true.

---

Full diff: https://github.com/llvm/llvm-project/pull/123891.diff

1 Files Affected:

• (modified) lld/MachO/SyntheticSections.cpp (+1-1)

diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
index 417b7cf93efa7d..97164e5992b8c7 100644
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -1958,7 +1958,7 @@ void InitOffsetsSection::writeTo(uint8_t *buf) const {
   // FIXME: Add function specified by -init when that argument is implemented.
   for (ConcatInputSection *isec : sections) {
     for (const Reloc &rel : isec->relocs) {
-      const Symbol *referent = rel.referent.dyn_cast<Symbol *>();
+      const Symbol *referent = cast<Symbol *>(rel.referent);
       assert(referent && "section relocation should have been rejected");
       uint64_t offset = referent->getVA() - in.header->addr;
       // FIXME: Can we handle this gracefully?