Add helper methods to AArch64PauthAbiCoreInfo

- Convert AArch64PauthAbiCoreInfo to a struct with isValid(), size(), and comparison operators.
- Simplify comparison logic in readSecurityNotes() using operator!=.

Author: sivan-shani

lld/ELF/Arch/AArch64.cpp

@@ -1044,9 +1044,7 @@ AArch64BtiPac::AArch64BtiPac(Ctx &ctx) : AArch64(ctx) {
   // instructions.
 
   if (ctx.arg.zPacPlt) {
-    if (ctx.aarch64PauthAbiCoreInfo.has_value() &&
-        (ctx.aarch64PauthAbiCoreInfo->platform != 0 ||
-         ctx.aarch64PauthAbiCoreInfo->version != 0))
+    if (ctx.aarch64PauthAbiCoreInfo && ctx.aarch64PauthAbiCoreInfo->isValid())
       pacEntryKind = PEK_Auth;
     else
       pacEntryKind = PEK_AuthHint;

lld/ELF/Config.h

@@ -142,6 +142,14 @@ enum class ReportPolicy { None, Warning, Error };
 struct AArch64PauthAbiCoreInfo {
   uint64_t platform;
   uint64_t version;
+  bool isValid() const { return platform || version; }
+  static constexpr size_t size() { return sizeof(platform) + sizeof(version); }
+  bool operator==(const AArch64PauthAbiCoreInfo &other) const {
+    return platform == other.platform && version == other.version;
+  }
+  bool operator!=(const AArch64PauthAbiCoreInfo &other) const {
+    return !(*this == other);
+  }
 };
 
 struct SymbolVersion {

lld/ELF/Driver.cpp

@@ -2848,9 +2848,8 @@ static void readSecurityNotes(Ctx &ctx) {
       referenceFileName = (*it)->getName();
     }
   }
-  bool hasValidPauthAbiCoreInfo = ctx.aarch64PauthAbiCoreInfo.has_value() &&
-                                  (ctx.aarch64PauthAbiCoreInfo->platform != 0 ||
-                                   ctx.aarch64PauthAbiCoreInfo->version != 0);
+  bool hasValidPauthAbiCoreInfo =
+      ctx.aarch64PauthAbiCoreInfo && ctx.aarch64PauthAbiCoreInfo->isValid();
 
   auto report = [&](ReportPolicy policy) -> ELFSyncStream {
     return {ctx, toDiagLevel(policy)};
@@ -2922,25 +2921,19 @@ static void readSecurityNotes(Ctx &ctx) {
       continue;
     }
 
-    if (ctx.aarch64PauthAbiCoreInfo->platform !=
-        f->aarch64PauthAbiCoreInfo->platform)
-      Err(ctx) << "incompatible AArch64 PAuth Platform Values\n>>> "
-               << referenceFileName << ": 0x"
-               << toHex(ctx.aarch64PauthAbiCoreInfo->platform,
-                        /*LowerCase=*/true)
-               << "\n>>> " << f << ": 0x"
-               << toHex(f->aarch64PauthAbiCoreInfo->platform,
-                        /*LowerCase=*/true);
-
-    if (ctx.aarch64PauthAbiCoreInfo->version !=
-        f->aarch64PauthAbiCoreInfo->version)
-      Err(ctx) << "incompatible AArch64 PAuth Version Values\n>>> "
-               << referenceFileName << ": 0x"
-               << toHex(ctx.aarch64PauthAbiCoreInfo->version,
-                        /*LowerCase=*/true)
-               << "\n>>> " << f << ": 0x"
-               << toHex(f->aarch64PauthAbiCoreInfo->version,
-                        /*LowerCase=*/true);
+    if (ctx.aarch64PauthAbiCoreInfo != f->aarch64PauthAbiCoreInfo)
+      Err(ctx)
+          << "incompatible values of AArch64 PAuth core info found\n"
+          << "platform:\n"
+          << ">>> " << referenceFileName << ": 0x"
+          << toHex(ctx.aarch64PauthAbiCoreInfo->platform, /*LowerCase=*/true)
+          << "\n>>> " << f << ": 0x"
+          << toHex(f->aarch64PauthAbiCoreInfo->platform, /*LowerCase=*/true)
+          << "\nversion:\n"
+          << ">>> " << referenceFileName << ": 0x"
+          << toHex(ctx.aarch64PauthAbiCoreInfo->version, /*LowerCase=*/true)
+          << "\n>>> " << f << ": 0x"
+          << toHex(f->aarch64PauthAbiCoreInfo->version, /*LowerCase=*/true);
   }
 
   // Force enable Shadow Stack.

lld/ELF/SyntheticSections.cpp

@@ -346,7 +346,7 @@ void GnuPropertySection::writeTo(uint8_t *buf) {
 
   if (ctx.aarch64PauthAbiCoreInfo) {
     write32(ctx, buf + offset + 0, GNU_PROPERTY_AARCH64_FEATURE_PAUTH);
-    write32(ctx, buf + offset + 4, sizeof(uint64_t) * 2);
+    write32(ctx, buf + offset + 4, AArch64PauthAbiCoreInfo::size());
     write64(ctx, buf + offset + 8, ctx.aarch64PauthAbiCoreInfo->platform);
     write64(ctx, buf + offset + 16, ctx.aarch64PauthAbiCoreInfo->version);
   }

lld/test/ELF/aarch64-feature-pauth.s

@@ -12,7 +12,11 @@
 # RUN: llvm-mc -filetype=obj -triple=aarch64-linux-gnu abi-tag2.s -o tag2.o
 # RUN: not ld.lld tag1.o tag1a.o tag2.o -o /dev/null 2>&1 | FileCheck --check-prefix ERR1 %s
 
-# ERR1:      error: incompatible AArch64 PAuth Version Values
+# ERR1:      error: incompatible values of AArch64 PAuth core info found
+# ERR1-NEXT: platform:
+# ERR1-NEXT: >>> tag1.o: 0x2a
+# ERR1-NEXT: >>> tag2.o: 0x2a
+# ERR1-NEXT: version:
 # ERR1-NEXT: >>> tag1.o: 0x01
 # ERR1-NEXT: >>> tag2.o: 0x02