[lld] Replace LLVM_ATTRIBUTE_UNUSED with [[maybe_unused]] (NFC)

[kazutakahirata]

This patch replaces LLVM_ATTRIBUTE_UNUSED with [[maybe_unused]],
introduced as part of C++17.

[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-macho

Author: Kazu Hirata (kazutakahirata)

Changes

This patch replaces LLVM_ATTRIBUTE_UNUSED with [[maybe_unused]],
introduced as part of C++17.

---

Full diff: https://github.com/llvm/llvm-project/pull/163701.diff

2 Files Affected:

• (modified) lld/ELF/Symbols.cpp (+1-1)
• (modified) lld/MachO/Driver.cpp (+1-1)

diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index de839795c50d7..220ec99c22e6f 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -35,7 +35,7 @@ template <typename T> struct AssertSymbol {
                 "SymbolUnion not aligned enough");
 };
 
-LLVM_ATTRIBUTE_UNUSED static inline void assertSymbols() {
+[[maybe_unused]] static inline void assertSymbols() {
   AssertSymbol<Defined>();
   AssertSymbol<CommonSymbol>();
   AssertSymbol<Undefined>();
diff --git a/lld/MachO/Driver.cpp b/lld/MachO/Driver.cpp
index 94f441b7643a7..bfd35aef72b58 100644
--- a/lld/MachO/Driver.cpp
+++ b/lld/MachO/Driver.cpp
@@ -355,7 +355,7 @@ void multiThreadedPageInBackground(DeferredFiles &deferred) {
     // Reference all file's mmap'd pages to load them into memory.
     for (const char *page = buff.data(), *end = page + buff.size(); page < end;
          page += pageSize) {
-      LLVM_ATTRIBUTE_UNUSED volatile char t = *page;
+      [[maybe_unused]] volatile char t = *page;
       (void)t;
     }
   };