Emit an IRELATIVE relocation instead of GLOB_DAT for an ifunc in DSO

Fixes #1385

src/output-chunks.cc

@@ -1323,12 +1323,6 @@ static std::vector<GotEntry<E>> get_got_entries(Context<E> &ctx) {
   for (Symbol<E> *sym : ctx.got->got_syms) {
     i64 idx = sym->get_got_idx(ctx);
 
-    // If a symbol is imported, let the dynamic linker to resolve it.
-    if (sym->is_imported) {
-      add({idx, 0, E::R_GLOB_DAT, sym});
-      continue;
-    }
-
     // IFUNC always needs to be fixed up by the dynamic linker.
     if constexpr (supports_ifunc<E>) {
       if (sym->is_ifunc()) {
@@ -1342,6 +1336,12 @@ static std::vector<GotEntry<E>> get_got_entries(Context<E> &ctx) {
       }
     }
 
+    // If a symbol is imported, let the dynamic linker to resolve it.
+    if (sym->is_imported) {
+      add({idx, 0, E::R_GLOB_DAT, sym});
+      continue;
+    }
+
     // If we know an address at link-time, fill that GOT entry now.
     // It may need a base relocation, though.
     if (ctx.arg.pic && sym->is_relative())

test/arch-x86_64-function-multiversion.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+. $(dirname $0)/common.inc
+
+cat <<EOF | $GCC -o $t/a.o -c -xc++ - -fPIC
+#include <iostream>
+
+class Hello {
+public:
+  __attribute__((target("default"))) void say() { std::cout << "Hello\n"; }
+  __attribute__((target("popcnt")))  void say() { std::cout << "Howdy\n"; }
+};
+
+void hello() {
+  Hello().say();
+}
+EOF
+
+$CXX -B. -shared -o $t/b.so $t/a.o
+
+cat <<EOF | $CC -o $t/c.o -c -xc++ - -fPIC
+void hello();
+int main() { hello(); }
+EOF
+
+$CXX -B. -o $t/exe $t/b.so $t/c.o
+$QEMU $t/exe | grep -q '^H'