[Sema] Add sizeof diagnostics for bzero

For memset (and others) we can get diagnostics like:

  struct stat { int x; };
  void foo(struct stat *stamps) {
    bzero(stamps, sizeof(stamps));
    memset(stamps, 0, sizeof(stamps));
  }

  t.c:7:28: warning: 'memset' call operates on objects of type 'struct stat' while the size is based on a different type 'struct stat *' [-Wsizeof-pointer-memaccess]
    memset(stamps, 0, sizeof(stamps));
           ~~~~~~            ^~~~~~
  t.c:7:28: note: did you mean to dereference the argument to 'sizeof' (and multiply it by the number of elements)?
    memset(stamps, 0, sizeof(stamps));
                             ^~~~~~

This patch implements the same class of warnings for bzero.

Differential Revision: https://reviews.llvm.org/D22525

rdar://problem/18963514

llvm-svn: 277787

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index d1e8d25ea04..813a20a9f52 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3408,6 +3408,10 @@ unsigned FunctionDecl::getMemoryFunctionKind() const {
   case Builtin::BIstrlen:
     return Builtin::BIstrlen;
 
+  case Builtin::BI__builtin_bzero:
+  case Builtin::BIbzero:
+    return Builtin::BIbzero;
+
   default:
     if (isExternC()) {
       if (FnInfo->isStr("memset"))
@@ -3430,6 +3434,8 @@ unsigned FunctionDecl::getMemoryFunctionKind() const {
         return Builtin::BIstrndup;
       else if (FnInfo->isStr("strlen"))
         return Builtin::BIstrlen;
+      else if (FnInfo->isStr("bzero"))
+        return Builtin::BIbzero;
     }
     break;
   }