diff --git a/SConstruct b/SConstruct
--- a/SConstruct
+++ b/SConstruct
@@ -180,6 +180,8 @@
         use_env[key] = val
 
 main = Environment(ENV=use_env)
+main.Decider('MD5-timestamp')
+main.SetOption('implicit_cache', 1)
 main.root = Dir(".")         # The current directory (where this file lives).
 main.srcdir = Dir("src")     # The source directory
 
diff --git a/src/SConscript b/src/SConscript
--- a/src/SConscript
+++ b/src/SConscript
@@ -953,24 +953,32 @@
     print 'Unknown compiler, please fix compiler options'
     Exit(1)
 
-makeEnv('debug', '.do',
-        CCFLAGS = Split(ccflags['debug']),
-        CPPDEFINES = ['DEBUG', 'TRACING_ON=1'])
+targetTypes = [target.split('.')[-1] for target in BUILD_TARGETS]
+targetTypes += [target.split('/')[-3] for target in BUILD_TARGETS]
+# Debug binary
+if 'debug' in targetTypes:
+    makeEnv('debug', '.do',
+            CCFLAGS = Split(ccflags['debug']),
+            CPPDEFINES = ['DEBUG', 'TRACING_ON=1'])
 
 # Optimized binary
-makeEnv('opt', '.o',
-        CCFLAGS = Split(ccflags['opt']),
-        CPPDEFINES = ['TRACING_ON=1'])
+if 'opt' in targetTypes:
+    makeEnv('opt', '.o',
+            CCFLAGS = Split(ccflags['opt']),
+            CPPDEFINES = ['TRACING_ON=1'])
 
 # "Fast" binary
-makeEnv('fast', '.fo', strip = True,
-        CCFLAGS = Split(ccflags['fast']),
-        CPPDEFINES = ['NDEBUG', 'TRACING_ON=0'])
+if 'fast' in targetTypes:
+    makeEnv('fast', '.fo', strip = True,
+            CCFLAGS = Split(ccflags['fast']),
+            CPPDEFINES = ['NDEBUG', 'TRACING_ON=0'])
 
 # Profiled binary
-makeEnv('prof', '.po',
-        CCFLAGS = Split(ccflags['prof']),
-        CPPDEFINES = ['NDEBUG', 'TRACING_ON=0'],
-        LINKFLAGS = '-pg')
+if 'prof' in targetTypes:
+    makeEnv('prof', '.po',
+            CCFLAGS = Split(ccflags['prof']),
+            CPPDEFINES = ['NDEBUG', 'TRACING_ON=0'],
+            LINKFLAGS = '-pg')
+
 
 Return('envList')
diff --git a/src/mem/protocol/SConscript b/src/mem/protocol/SConscript
--- a/src/mem/protocol/SConscript
+++ b/src/mem/protocol/SConscript
@@ -69,7 +69,7 @@
     slicc = SLICC(filepath, verbose=False)
     slicc.process()
     slicc.writeCodeFiles(protocol_dir.abspath)
-    if not env['NO_HTML']:
+    if env['SLICC_HTML']:
         slicc.writeHTMLFiles(html_dir.abspath)
 
     target.extend([protocol_dir.File(f) for f in sorted(slicc.files())])
@@ -82,7 +82,7 @@
     slicc = SLICC(filepath, verbose=True)
     slicc.process()
     slicc.writeCodeFiles(protocol_dir.abspath)
-    if not env['NO_HTML']:
+    if env['SLICC_HTML']:
         slicc.writeHTMLFiles(html_dir.abspath)
 
 slicc_builder = Builder(action=MakeAction(slicc_action, Transform("SLICC")),
diff --git a/src/mem/protocol/SConsopts b/src/mem/protocol/SConsopts
--- a/src/mem/protocol/SConsopts
+++ b/src/mem/protocol/SConsopts
@@ -48,5 +48,5 @@
 sticky_vars.AddVariables(opt)
 export_vars += ['PROTOCOL']
 
-opt = BoolVariable('NO_HTML', 'Do not create HTML files', False)
+opt = BoolVariable('SLICC_HTML', 'Create HTML files', False)
 sticky_vars.AddVariables(opt)