[Patch] BaseTool: Add cache for the result of SkipAutogen.

[BobCF <bob.c.feng@intel.com>]

Add a cache for the value of skip ModuleAutoGen
process flag. This cache can improve build performance.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
---
 BaseTools/Source/Python/AutoGen/AutoGen.py   | 4 ++++
 BaseTools/Source/Python/Common/GlobalData.py | 1 +
 2 files changed, 5 insertions(+)

diff --git a/BaseTools/Source/Python/AutoGen/AutoGen.py b/BaseTools/Source/Python/AutoGen/AutoGen.py
index 381dbc0a71..fc242992b7 100644
--- a/BaseTools/Source/Python/AutoGen/AutoGen.py
+++ b/BaseTools/Source/Python/AutoGen/AutoGen.py
@@ -4305,15 +4305,18 @@ class ModuleAutoGen(AutoGen):
 
     ## Decide whether we can skip the ModuleAutoGen process
     def CanSkipbyHash(self):
         if GlobalData.gUseHashCache:
             return not self.GenModuleHash()
+        return False
 
     ## Decide whether we can skip the ModuleAutoGen process
     #  If any source file is newer than the module than we cannot skip
     #
     def CanSkip(self):
+        if self.MetaFile in GlobalData.gSikpAutoGenCache:
+            return True
         if not os.path.exists(self.GetTimeStampPath()):
             return False
         #last creation time of the module
         DstTimeStamp = os.stat(self.GetTimeStampPath())[8]
 
@@ -4328,10 +4331,11 @@ class ModuleAutoGen(AutoGen):
                     return False
                 if source not in ModuleAutoGen.TimeDict :
                     ModuleAutoGen.TimeDict[source] = os.stat(source)[8]
                 if ModuleAutoGen.TimeDict[source] > DstTimeStamp:
                     return False
+        GlobalData.gSikpAutoGenCache.add(self.MetaFile)
         return True
 
     def GetTimeStampPath(self):
         if self._TimeStampPath is None:
             self._TimeStampPath = os.path.join(self.MakeFileDir, 'AutoGenTimeStamp')
diff --git a/BaseTools/Source/Python/Common/GlobalData.py b/BaseTools/Source/Python/Common/GlobalData.py
index afb3d8f020..fac7cde708 100644
--- a/BaseTools/Source/Python/Common/GlobalData.py
+++ b/BaseTools/Source/Python/Common/GlobalData.py
@@ -111,5 +111,6 @@ gBinCacheDest = None
 gBinCacheSource = None
 gPlatformHash = None
 gPackageHash = {}
 gModuleHash = {}
 gEnableGenfdsMultiThread = False
+gSikpAutoGenCache = set()
-- 
2.16.2.windows.1