Patch to check at compile time for overflow when

__builtin___memcpy_chk and similar builtins are
being used. Patch by Jacques Fortier (with added 
clang tests).  rdar://11076881

llvm-svn: 218063

2 files changed, 24 insertions, 3 deletions

diff --git a/clang/test/Sema/builtin-object-size.c b/clang/test/Sema/builtin-object-size.c
index 0abc27ba187..db4832e347a 100644
--- a/clang/test/Sema/builtin-object-size.c
+++ b/clang/test/Sema/builtin-object-size.c
@@ -23,6 +23,6 @@ int f3() {
 // rdar://6252231 - cannot call vsnprintf with va_list on x86_64
 void f4(const char *fmt, ...) {
  __builtin_va_list args;
- __builtin___vsnprintf_chk (0, 42, 0, 11, fmt, args);
+ __builtin___vsnprintf_chk (0, 42, 0, 11, fmt, args); // expected-warning {{'__builtin___vsnprintf_chk' will always overflow destination buffer}}
 }
 
diff --git a/clang/test/Sema/builtins.c b/clang/test/Sema/builtins.c
index 8e3a60ab067..f8df2f85cf6 100644
--- a/clang/test/Sema/builtins.c
+++ b/clang/test/Sema/builtins.c
@@ -215,10 +215,31 @@ void Test19(void)
         strlcpy(buf, b, sizeof(b)); // expected-warning {{size argument in 'strlcpy' call appears to be size of the source; expected the size of the destination}} \\
                                     // expected-note {{change size argument to be the size of the destination}}
         __builtin___strlcpy_chk(buf, b, sizeof(b), __builtin_object_size(buf, 0)); // expected-warning {{size argument in '__builtin___strlcpy_chk' call appears to be size of the source; expected the size of the destination}} \
-                                    // expected-note {{change size argument to be the size of the destination}}
+                                    // expected-note {{change size argument to be the size of the destination}} \
+				    // expected-warning {{'__builtin___strlcpy_chk' will always overflow destination buffer}}
 
         strlcat(buf, b, sizeof(b)); // expected-warning {{size argument in 'strlcat' call appears to be size of the source; expected the size of the destination}} \
                                     // expected-note {{change size argument to be the size of the destination}}
+				    
         __builtin___strlcat_chk(buf, b, sizeof(b), __builtin_object_size(buf, 0)); // expected-warning {{size argument in '__builtin___strlcat_chk' call appears to be size of the source; expected the size of the destination}} \
-                                                                                   // expected-note {{change size argument to be the size of the destination}}
+                                                                                   // expected-note {{change size argument to be the size of the destination}} \
+				                                                   // expected-warning {{'__builtin___strlcat_chk' will always overflow destination buffer}}
+}
+
+// rdar://11076881
+char * Test20(char *p, const char *in, unsigned n)
+{
+    static char buf[10];
+
+    __builtin___memcpy_chk (&buf[6], in, 5, __builtin_object_size (&buf[6], 0)); // expected-warning {{'__builtin___memcpy_chk' will always overflow destination buffer}}
+
+    __builtin___memcpy_chk (p, "abcde", n, __builtin_object_size (p, 0));
+
+    __builtin___memcpy_chk (&buf[5], "abcde", 5, __builtin_object_size (&buf[5], 0));
+
+    __builtin___memcpy_chk (&buf[5], "abcde", n, __builtin_object_size (&buf[5], 0));
+
+    __builtin___memcpy_chk (&buf[6], "abcde", 5, __builtin_object_size (&buf[6], 0)); // expected-warning {{'__builtin___memcpy_chk' will always overflow destination buffer}}
+
+    return buf;
 }