diff --git a/include/Support/DataTypes.h.in b/include/Support/DataTypes.h.in
index 895aa93509c..0690ee7e58f 100644
--- a/include/Support/DataTypes.h.in
+++ b/include/Support/DataTypes.h.in
@@ -39,8 +39,9 @@
 // built-in data types.
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
-typedef int int32_t;
-typedef unsigned uint32_t;
+typedef signed   int int32_t;
+typedef unsigned int uint32_t;
+typedef signed   int ssize_t;
 #endif
 
 #if !defined(INT64_MAX)
diff --git a/include/llvm/Support/DataTypes.h.in b/include/llvm/Support/DataTypes.h.in
index 895aa93509c..0690ee7e58f 100644
--- a/include/llvm/Support/DataTypes.h.in
+++ b/include/llvm/Support/DataTypes.h.in
@@ -39,8 +39,9 @@
 // built-in data types.
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
-typedef int int32_t;
-typedef unsigned uint32_t;
+typedef signed   int int32_t;
+typedef unsigned int uint32_t;
+typedef signed   int ssize_t;
 #endif
 
 #if !defined(INT64_MAX)