scons: Separate debug flags from debug-format flags

Debug flags are flags that aid with debugging by printing
relevant information when enabled. Debug-formatting flags
define how the debug flags will print the information.

Although a viability, this patch does not support declaring
compound format flags.

As a side effect, now debug flags and debug-formatting flags
are printed in different lists, when using --debug-help.

Change-Id: Ieae68745276218cf4e9c1d37d7bf3bd1f19709ae
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39076
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/SConscript

@@ -618,20 +618,24 @@ Export('GTest')
 # Debug Flags
 #
 debug_flags = {}
-def DebugFlag(name, desc=None):
+def DebugFlag(name, desc=None, fmt=False):
     if name in debug_flags:
         raise AttributeError("Flag {} already specified".format(name))
-    debug_flags[name] = (name, (), desc)
+    debug_flags[name] = (name, (), desc, fmt)
 
 def CompoundFlag(name, flags, desc=None):
     if name in debug_flags:
         raise AttributeError("Flag {} already specified".format(name))
 
     compound = tuple(flags)
-    debug_flags[name] = (name, compound, desc)
+    debug_flags[name] = (name, compound, desc, False)
+
+def DebugFormatFlag(name, desc=None):
+    DebugFlag(name, desc, True)
 
 Export('DebugFlag')
 Export('CompoundFlag')
+Export('DebugFormatFlag')
 
 ########################################################################
 #
@@ -1109,11 +1113,14 @@ namespace Debug {
 ''')
 
     for name, flag in sorted(source[0].read().items()):
-        n, compound, desc = flag
+        n, compound, desc, fmt = flag
         assert n == name
 
         if not compound:
-            code('SimpleFlag $name("$name", "$desc");')
+            if fmt:
+                code('SimpleFlag $name("$name", "$desc", true);')
+            else:
+                code('SimpleFlag $name("$name", "$desc", false);')
         else:
             comp_code('CompoundFlag $name("$name", "$desc", {')
             comp_code.indent()
@@ -1132,7 +1139,7 @@ def makeDebugFlagHH(target, source, env):
     assert(len(target) == 1 and len(source) == 1)
 
     val = eval(source[0].get_contents())
-    name, compound, desc = val
+    name, compound, desc, fmt = val
 
     code = code_formatter()
 
@@ -1168,7 +1175,7 @@ namespace Debug {
     code.write(str(target[0]))
 
 for name,flag in sorted(debug_flags.items()):
-    n, compound, desc = flag
+    n, compound, desc, fmt = flag
     assert n == name
 
     hh_file = 'debug/%s.hh' % name

src/base/SConscript

@@ -102,10 +102,6 @@ GTest('chunk_generator.test', 'chunk_generator.test.cc')
 DebugFlag('Annotate', "State machine annotation debugging")
 DebugFlag('AnnotateQ', "State machine annotation queue debugging")
 DebugFlag('AnnotateVerbose', "Dump all state machine annotation details")
-DebugFlag('FmtFlag', "Show the --debug-flag that enabled each debug message")
-DebugFlag('FmtStackTrace',
-    "Print a stack trace after every debug message")
-DebugFlag('FmtTicksOff', "Don't show tick count on debug messages")
 DebugFlag('GDBAcc', "Remote debugger accesses")
 DebugFlag('GDBExtra', "Dump extra information on reads and writes")
 DebugFlag('GDBMisc', "Breakpoints, traps, watchpoints, etc.")
@@ -124,3 +120,8 @@ CompoundFlag('GDBAll',
 CompoundFlag('AnnotateAll', ['Annotate', 'AnnotateQ', 'AnnotateVerbose'],
     desc="All Annotation flags")
 
+DebugFormatFlag('FmtFlag',
+    "Show the --debug-flag that enabled each debug message")
+DebugFormatFlag('FmtStackTrace',
+    "Print a stack trace after every debug message")
+DebugFormatFlag('FmtTicksOff', "Don't show tick count on debug messages")

src/base/debug.hh

@@ -81,18 +81,31 @@ class Flag
 class SimpleFlag : public Flag
 {
   protected:
+    /** Whether this flag changes debug formatting. */
+    const bool _isFormat = false;
+
     bool _tracing = false; // tracing is enabled and flag is on
     bool _enabled = false; // flag enablement status
 
     void sync() override { _tracing = _globalEnable && _enabled; }
 
   public:
-    SimpleFlag(const char *name, const char *desc) : Flag(name, desc) {}
+    SimpleFlag(const char *name, const char *desc, bool is_format=false)
+      : Flag(name, desc), _isFormat(is_format)
+    {}
 
     bool enabled() const override { return _tracing; }
 
     void enable() override  { _enabled = true;  sync(); }
     void disable() override { _enabled = false; sync(); }
+
+    /**
+     * Checks whether this flag is a conventional debug flag, or a flag that
+     * modifies the way debug information is printed.
+     *
+     * @return True if this flag is a debug-formatting flag.
+     */
+    bool isFormat() const { return _isFormat; }
 };
 
 class CompoundFlag : public Flag

src/base/debug.test.cc

@@ -60,6 +60,17 @@ TEST(DebugFlagDeathTest, UniqueNames)
     EXPECT_EQ(expected, actual);
 }
 
+/** Test format attribute. */
+TEST(DebugFlagTest, IsFormat)
+{
+    Debug::SimpleFlag flag_a("FlagIsFormatTestA", "", true);
+    EXPECT_TRUE(flag_a.isFormat());
+    Debug::SimpleFlag flag_b("FlagIsFormatTestB", "", false);
+    EXPECT_FALSE(flag_b.isFormat());
+    Debug::SimpleFlag flag_c("FlagIsFormatTestC", "");
+    EXPECT_FALSE(flag_c.isFormat());
+}
+
 /** Test enabling and disabling simple flags, as well as the global enabler. */
 TEST(DebugSimpleFlagTest, Enabled)
 {

src/python/m5/debug.py

@@ -35,8 +35,8 @@ def help():
     sorted_flags = sorted(flags.items(), key=lambda kv: kv[0])
 
     print("Base Flags:")
-    for name, flag in filter(lambda kv: not isinstance(kv[1], CompoundFlag),
-                             sorted_flags):
+    for name, flag in filter(lambda kv: isinstance(kv[1], SimpleFlag)
+                             and not kv[1].isFormat, sorted_flags):
         print("    %s: %s" % (name, flag.desc))
     print()
     print("Compound Flags:")
@@ -45,6 +45,11 @@ def help():
         print("    %s: %s" % (name, flag.desc))
         printList([ c.name for c in flag.kids() ], indent=8)
     print()
+    print("Formatting Flags:")
+    for name, flag in filter(lambda kv: isinstance(kv[1], SimpleFlag)
+                             and kv[1].isFormat, sorted_flags):
+        print("    %s: %s" % (name, flag.desc))
+    print()
 
 class AllFlags(Mapping):
     def __init__(self):

src/python/pybind11/debug.cc

@@ -110,7 +110,9 @@ pybind_init_debug(py::module_ &m_native)
             })
         ;
 
-    py::class_<Debug::SimpleFlag>(m_debug, "SimpleFlag", c_flag);
+    py::class_<Debug::SimpleFlag>(m_debug, "SimpleFlag", c_flag)
+        .def_property_readonly("isFormat", &Debug::SimpleFlag::isFormat)
+        ;
     py::class_<Debug::CompoundFlag>(m_debug, "CompoundFlag", c_flag)
         .def("kids", &Debug::CompoundFlag::kids)
         ;