[lld] e5b8a7c - [PAC][ELF] Make non-preemptible IFUNC GOT assertion an error and extend (#214456)

[via llvm-commits]

Author: Jessica Clarke
Date: 2026-08-19T20:51:29-07:00
New Revision: e5b8a7c1eb09dd5abbbc75c3e2b1e36a14d92dc6

URL: https://github.com/llvm/llvm-project/commit/e5b8a7c1eb09dd5abbbc75c3e2b1e36a14d92dc6
DIFF: https://github.com/llvm/llvm-project/commit/e5b8a7c1eb09dd5abbbc75c3e2b1e36a14d92dc6.diff

LOG: [PAC][ELF] Make non-preemptible IFUNC GOT assertion an error and extend (#214456)

Support for R_AARCH64_AUTH_IRELATIVE is not yet present in LLD, but we
accept various input that would give rise to needing it. For the direct
reloc case, replaceWithDefined asserts (rather than give an error
message) this was not requested, whilst for the non-direct reloc case it
silently ignores which GOT type was requested. In the latter case, and
the former when assertions are disabled, this results in mis-linking the
object, producing one with a non-AUTH GOT entry, that would presumably
then fail the AUTDA operation in any user of it (aside from the IPLT
entry generated by LLD).

Fixes: 417d2d7ce694 ("[PAC][lld][AArch64][ELF] Support signed GOT
(#113815)")

Added: 
    lld/test/ELF/aarch64-gnu-ifunc-nonpreemptible-pauth.s

Modified: 
    lld/ELF/Relocations.cpp

Removed: 
    


################################################################################
diff  --git a/lld/ELF/Relocations.cpp b/lld/ELF/Relocations.cpp
index d335da63ebf84..405154d598189 100644
--- a/lld/ELF/Relocations.cpp
+++ b/lld/ELF/Relocations.cpp
@@ -1245,6 +1245,14 @@ static bool handleNonPreemptibleIfunc(Ctx &ctx, Symbol &sym, uint16_t flags) {
   // Skip unreferenced non-preemptible ifunc.
   if (!(flags & (NEEDS_GOT | NEEDS_PLT | HAS_DIRECT_RELOC)))
     return true;
+  // We only support one kind of GOT entry, and IPLT entries currently always
+  // use non-AUTH GOT entries.
+  if ((flags & NEEDS_GOT) && (flags & NEEDS_GOT_AUTH)) {
+    auto diag = Err(ctx);
+    diag << "AUTH GOT entry for non-preemptible ifunc '" << sym.getName()
+         << "' requested, but R_AARCH64_AUTH_IRELATIVE is not supported yet";
+    return true;
+  }
 
   sym.isInIplt = true;
 
@@ -1267,11 +1275,8 @@ static bool handleNonPreemptibleIfunc(Ctx &ctx, Symbol &sym, uint16_t flags) {
     // don't try to call the PLT as if it were an ifunc resolver.
     d.type = STT_FUNC;
 
-    if (flags & NEEDS_GOT) {
-      assert(!(flags & NEEDS_GOT_AUTH) &&
-             "R_AARCH64_AUTH_IRELATIVE is not supported yet");
+    if (flags & NEEDS_GOT)
       addGotEntry(ctx, sym);
-    }
   } else if (flags & NEEDS_GOT) {
     // Redirect GOT accesses to point to the Igot.
     sym.gotInIgot = true;

diff  --git a/lld/test/ELF/aarch64-gnu-ifunc-nonpreemptible-pauth.s b/lld/test/ELF/aarch64-gnu-ifunc-nonpreemptible-pauth.s
new file mode 100644
index 0000000000000..4cb8fc53d302c
--- /dev/null
+++ b/lld/test/ELF/aarch64-gnu-ifunc-nonpreemptible-pauth.s
@@ -0,0 +1,21 @@
+# REQUIRES: aarch64
+# RUN: llvm-mc -filetype=obj -triple=aarch64 --defsym direct=0 %s -o %t.o
+# RUN: not ld.lld %t.o -o %t 2>&1 | FileCheck %s
+# RUN: llvm-mc -filetype=obj -triple=aarch64 --defsym direct=1 %s -o %t.direct.o
+# RUN: not ld.lld %t.direct.o -o %t.direct 2>&1 | FileCheck %s
+
+# CHECK: error: AUTH GOT entry for non-preemptible ifunc 'ifunc' requested, but R_AARCH64_AUTH_IRELATIVE is not supported yet
+
+.globl ifunc
+.type ifunc, @gnu_indirect_function
+ifunc:
+  ret
+
+.globl _start
+.type _start, @function
+_start:
+  adrp x0, :got_auth:ifunc
+  ldr x1, [x0, :got_auth_lo12:ifunc]
+.if direct == 1
+  adrp x2, ifunc
+.endif