[Patch] BaseTools: Fix incremental build failure that override file be removed

[Yonghong Zhu <yonghong.zhu@intel.com>]

Fix a Incremental build failure. The case is: Both A and B package will
include a same .h file, and in the driver's packages section, A
package is listed before B package, so we will use the .h file in the A
package and build success, then we directly delete the .h file in package
A, it cause increment build failure since in the AutoGenTimeStamp file
the .h file in A can't be found.

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
---
 BaseTools/Source/Python/AutoGen/AutoGen.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/BaseTools/Source/Python/AutoGen/AutoGen.py b/BaseTools/Source/Python/AutoGen/AutoGen.py
index e89b61d..356eb21 100644
--- a/BaseTools/Source/Python/AutoGen/AutoGen.py
+++ b/BaseTools/Source/Python/AutoGen/AutoGen.py
@@ -4208,10 +4208,12 @@ class ModuleAutoGen(AutoGen):
             return False
 
         with open(self.GetTimeStampPath(),'r') as f:
             for source in f:
                 source = source.rstrip('\n')
+                if not os.path.exists(source):
+                    return False
                 if source not in ModuleAutoGen.TimeDict :
                     ModuleAutoGen.TimeDict[source] = os.stat(source)[8]
                 if ModuleAutoGen.TimeDict[source] > DstTimeStamp:
                     return False
         return True
-- 
2.6.1.windows.1