[analyzer] Explain why we have system-header-simulator*.h files.

Suggested by Csaba. Text based on an e-mail of mine on cfe-dev.

llvm-svn: 174213

clang/test/Analysis/Inputs/system-header-simulator-cxx.h

@@ -1,3 +1,8 @@
+// Like the compiler, the static analyzer treats some functions differently if
+// they come from a system header -- for example, it is assumed that system
+// functions do not arbitrarily free() their parameters, and that some bugs
+// found in system headers cannot be fixed by the user and should be
+// suppressed.
 #pragma clang system_header
 
 namespace std {

clang/test/Analysis/Inputs/system-header-simulator-for-simple-stream.h

@@ -1,4 +1,8 @@
-
+// Like the compiler, the static analyzer treats some functions differently if
+// they come from a system header -- for example, it is assumed that system
+// functions do not arbitrarily free() their parameters, and that some bugs
+// found in system headers cannot be fixed by the user and should be
+// suppressed.
 #pragma clang system_header
 
 typedef struct __sFILE {

clang/test/Analysis/Inputs/system-header-simulator-objc.h

@@ -1,3 +1,8 @@
+// Like the compiler, the static analyzer treats some functions differently if
+// they come from a system header -- for example, it is assumed that system
+// functions do not arbitrarily free() their parameters, and that some bugs
+// found in system headers cannot be fixed by the user and should be
+// suppressed.
 #pragma clang system_header
 
 typedef unsigned int UInt32;

clang/test/Analysis/Inputs/system-header-simulator.h

@@ -1,3 +1,8 @@
+// Like the compiler, the static analyzer treats some functions differently if
+// they come from a system header -- for example, it is assumed that system
+// functions do not arbitrarily free() their parameters, and that some bugs
+// found in system headers cannot be fixed by the user and should be
+// suppressed.
 #pragma clang system_header
 
 typedef struct _FILE FILE;