config: add an option to list and select indirect branch predictor

Change-Id: I9a855d36de7d95b7785ff8a897899037cea6a3d8
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/15320
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

configs/common/BPConfig.py

@@ -86,3 +86,54 @@ def bp_names():
 for name, cls in inspect.getmembers(m5.objects, is_bp_class):
     _bp_classes[name] = cls
 
+
+# The same for indirect branch predictors...
+# Dictionary of mapping names of real branch predictor models to classes.
+_indirect_bp_classes = {}
+
+
+def is_indirect_bp_class(cls):
+    """Determine if a class is an indirect branch predictor that can be
+    instantiated"""
+
+    # We can't use the normal inspect.isclass because the ParamFactory
+    # and ProxyFactory classes have a tendency to confuse it.
+    try:
+        return issubclass(cls, m5.objects.IndirectPredictor) and \
+            not cls.abstract
+    except (TypeError, AttributeError):
+        return False
+
+def get_indirect(name):
+    """Get an Indirect BP class from a user provided class name or alias."""
+
+    try:
+        indirect_bp_class = _indirect_bp_classes[name]
+        return indirect_bp_class
+    except KeyError:
+        print("%s is not a valid indirect BP model." % (name,))
+        sys.exit(1)
+
+def print_indirect_bp_list():
+    """Print a list of available indirect BP classes."""
+
+    print("Available Indirect BranchPredictor classes:")
+    doc_wrapper = TextWrapper(initial_indent="\t\t", subsequent_indent="\t\t")
+    for name, cls in _indirect_bp_classes.items():
+        print("\t%s" % name)
+
+        # Try to extract the class documentation from the class help
+        # string.
+        doc = inspect.getdoc(cls)
+        if doc:
+            for line in doc_wrapper.wrap(doc):
+                print(line)
+
+def indirect_bp_names():
+    """Return a list of valid Indirect Branch Predictor names."""
+    return _indirect_bp_classes.keys()
+
+# Add all indirect BPs in the object hierarchy.
+for name, cls in inspect.getmembers(m5.objects, is_indirect_bp_class):
+    _indirect_bp_classes[name] = cls
+

configs/common/Options.py

@@ -64,6 +64,10 @@ def _listHWPTypes(option, opt, value, parser):
     HWPConfig.print_hwp_list()
     sys.exit(0)
 
+def _listIndirectBPTypes(option, opt, value, parser):
+    BPConfig.print_indirect_bp_list()
+    sys.exit(0)
+
 def _listMemTypes(option, opt, value, parser):
     MemConfig.print_mem_list()
     sys.exit(0)
@@ -162,12 +166,19 @@ def addCommonOptions(parser):
     parser.add_option("--list-bp-types",
                       action="callback", callback=_listBPTypes,
                       help="List available branch predictor types")
+    parser.add_option("--list-indirect-bp-types",
+                      action="callback", callback=_listIndirectBPTypes,
+                      help="List available indirect branch predictor types")
     parser.add_option("--bp-type", type="choice", default=None,
                       choices=BPConfig.bp_names(),
                       help = """
                       type of branch predictor to run with
                       (if not set, use the default branch predictor of
                       the selected CPU)""")
+    parser.add_option("--indirect-bp-type", type="choice",
+                      default="SimpleIndirectPredictor",
+                      choices=BPConfig.indirect_bp_names(),
+                      help = "type of indirect branch predictor to run with")
     parser.add_option("--list-hwp-types",
                       action="callback", callback=_listHWPTypes,
                       help="List available hardware prefetcher types")

configs/common/Simulation.py

@@ -483,6 +483,11 @@ def run(options, root, testsys, cpu_class):
             if options.bp_type:
                 bpClass = BPConfig.get(options.bp_type)
                 switch_cpus[i].branchPred = bpClass()
+            if options.indirect_bp_type:
+                IndirectBPClass = \
+                    BPConfig.get_indirect(options.indirect_bp_type)
+                switch_cpus[i].branchPred.branchPred.indirectBranchPred = \
+                    IndirectBPClass()
 
         # If elastic tracing is enabled attach the elastic trace probe
         # to the switch CPUs

configs/example/fs.py

@@ -206,6 +206,11 @@ def build_test_system(np):
             if options.bp_type:
                 bpClass = BPConfig.get(options.bp_type)
                 test_sys.cpu[i].branchPred = bpClass()
+            if options.indirect_bp_type:
+                IndirectBPClass = \
+                    BPConfig.get_indirect(options.indirect_bp_type)
+                test_sys.cpu[i].branchPred.indirectBranchPred = \
+                    IndirectBPClass()
             test_sys.cpu[i].createThreads()
 
         # If elastic tracing is enabled when not restoring from checkpoint and

configs/example/se.py

@@ -240,6 +240,10 @@ for i in range(np):
         bpClass = BPConfig.get(options.bp_type)
         system.cpu[i].branchPred = bpClass()
 
+    if options.indirect_bp_type:
+        indirectBPClass = BPConfig.get_indirect(options.indirect_bp_type)
+        system.cpu[i].branchPred.indirectBranchPred = indirectBPClass()
+
     system.cpu[i].createThreads()
 
 system.redirect_paths = redirect_paths(os.path.expanduser(options.chroot))