misc: Generate StateMachine debug includes in deterministic order

Since 3454a4a36e the order of the debug/
includes is non-deterministic which can result in unnecessary rebuilds.

Change-Id: I583d2caf70632e08fa59ac85073786270991edbc
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/54983
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/mem/slicc/symbols/StateMachine.py

@@ -105,6 +105,8 @@ class StateMachine(Symbol):
         self.objects = []
         self.TBEType   = None
         self.EntryType = None
+        # Python's sets are not sorted so we have to be careful when using
+        # this to generate deterministic output.
         self.debug_flags = set()
         self.debug_flags.add('RubyGenerated')
         self.debug_flags.add('RubySlicc')
@@ -516,8 +518,9 @@ void unset_tbe(${{self.TBEType.c_ident}}*& m_tbe_ptr);
 
         code(boolvec_include)
         code(base_include)
-
-        for f in self.debug_flags:
+        # We have to sort self.debug_flags in order to produce deterministic
+        # output and avoid unnecessary rebuilds of the generated files.
+        for f in sorted(self.debug_flags):
             code('#include "debug/${{f}}.hh"')
         code('''
 #include "mem/ruby/network/Network.hh"
@@ -1246,7 +1249,9 @@ $c_ident::functionalReadBuffers(PacketPtr& pkt, WriteMask &mask)
 #include "base/logging.hh"
 
 ''')
-        for f in self.debug_flags:
+        # We have to sort self.debug_flags in order to produce deterministic
+        # output and avoid unnecessary rebuilds of the generated files.
+        for f in sorted(self.debug_flags):
             code('#include "debug/${{f}}.hh"')
         code('''
 #include "mem/ruby/protocol/${ident}_Controller.hh"