diff -r 9846af5a0949 src/hotspot/os_cpu/solaris_x86/os_solaris_x86.cpp
--- a/src/hotspot/os_cpu/solaris_x86/os_solaris_x86.cpp	Mon Apr 19 12:47:46 2021 +0200
+++ b/src/hotspot/os_cpu/solaris_x86/os_solaris_x86.cpp	Wed Apr 21 06:25:25 2021 +0200
@@ -374,6 +374,11 @@
 #endif // AMD64
 }
 
+juint os::cpu_microcode_revision() {
+  // Stubbed out for now to get the Solaris x86 build working.
+  return 0;
+}
+
 bool os::is_allocatable(size_t bytes) {
 #ifdef AMD64
   return true;
diff -r 9846af5a0949 src/hotspot/os_cpu/solaris_x86/os_solaris_x86.hpp
--- a/src/hotspot/os_cpu/solaris_x86/os_solaris_x86.hpp	Mon Apr 19 12:47:46 2021 +0200
+++ b/src/hotspot/os_cpu/solaris_x86/os_solaris_x86.hpp	Wed Apr 21 06:25:25 2021 +0200
@@ -45,6 +45,7 @@
 #endif // AMD64
 
   static bool supports_sse();
+  static juint cpu_microcode_revision();
 
   static jlong rdtsc();