From fc500ad68ed5dc9718f9312a089cc3c809f5e0ae Mon Sep 17 00:00:00 2001
From: CristinaCristescu <bianca-cristina.cristescu@cern.ch>
Date: Fri, 8 Apr 2016 15:07:46 +0200
Subject: [PATCH] Reduce I/O operations caused by the check of address
 validity.

---
 include/cling/Utils/Validation.h              | 40 +----------
 .../NullDerefProtectionTransformer.cpp        |  6 ++
 lib/Utils/CMakeLists.txt                      |  1 +
 lib/Utils/Validation.cpp                      | 69 +++++++++++++++++++
 4 files changed, 77 insertions(+), 39 deletions(-)
 create mode 100644 lib/Utils/Validation.cpp

diff --git a/include/cling/Utils/Validation.h b/include/cling/Utils/Validation.h
index 1d374a33..c95a5e4d 100644
--- a/include/cling/Utils/Validation.h
+++ b/include/cling/Utils/Validation.h
@@ -10,50 +10,12 @@
 #ifndef CLING_UTILS_VALIDATION_H
 #define CLING_UTILS_VALIDATION_H
 
-#include "llvm/Config/config.h" // for LLVM_ON_WIN32
-
-#include <assert.h>
-#include <errno.h>
-#ifdef LLVM_ON_WIN32
-# define WIN32_LEAN_AND_MEAN
-# define NOGDI
-# include <Windows.h>
-#else
-# include <unistd.h>
-#endif
-
 namespace cling {
   namespace utils{
     // Checking whether the pointer points to a valid memory location
     // Used for checking of void* output
     // Should be moved to earlier stages (ex. IR) in the future
-    static bool isAddressValid(const void *P) {
-      if (!P || P == (void *) -1)
-        return false;
-
-#ifdef LLVM_ON_WIN32
-      MEMORY_BASIC_INFORMATION MBI;
-      if (!VirtualQuery(P, &MBI, sizeof(MBI)))
-        return false;
-      if (MBI.State != MEM_COMMIT)
-        return false;
-      return true;
-#else
-      // There is a POSIX way of finding whether an address can be accessed for
-      // reading: write() will return EFAULT if not.
-      int FD[2];
-      if (pipe(FD))
-        return false; // error in pipe()? Be conservative...
-      int NBytes = write(FD[1], P, 1/*byte*/);
-      close(FD[0]);
-      close(FD[1]);
-      if (NBytes != 1) {
-        assert(errno == EFAULT && "unexpected pipe write error");
-        return false;
-      }
-      return true;
-#endif
-    }
+    bool isAddressValid(const void *P);
   }
 }
 
diff --git a/lib/Interpreter/NullDerefProtectionTransformer.cpp b/lib/Interpreter/NullDerefProtectionTransformer.cpp
index 179f0ebd..0622ddc7 100644
--- a/lib/Interpreter/NullDerefProtectionTransformer.cpp
+++ b/lib/Interpreter/NullDerefProtectionTransformer.cpp
@@ -92,6 +92,12 @@ namespace cling {
       return true;
     }
 
+    bool VisitDecl (Decl* D)
+    {
+      printf("%ld\n", *(long*)D);
+      return true;
+    }
+
     bool VisitFunctionDecl(FunctionDecl* FD) {
       if (!FD->isConstexpr()) {
         CompoundStmt* CS = dyn_cast_or_null<CompoundStmt>(FD->getBody());
diff --git a/lib/Utils/CMakeLists.txt b/lib/Utils/CMakeLists.txt
index ec988064..578e9bb7 100644
--- a/lib/Utils/CMakeLists.txt
+++ b/lib/Utils/CMakeLists.txt
@@ -8,6 +8,7 @@
 
 add_cling_library(clingUtils
   AST.cpp
+  Validation.cpp
 
   LINK_LIBS
   clangCodeGen
diff --git a/lib/Utils/Validation.cpp b/lib/Utils/Validation.cpp
new file mode 100644
index 00000000..bd9e02b5
--- /dev/null
+++ b/lib/Utils/Validation.cpp
@@ -0,0 +1,69 @@
+//--------------------------------------------------------------------*- C++ -*-
+// CLING - the C++ LLVM-based InterpreterG :)
+// author:  Vassil Vassilev <vasil.georgiev.vasilev@cern.ch>
+//
+// This file is dual-licensed: you can choose to license it under the University
+// of Illinois Open Source License or the GNU Lesser General Public License. See
+// LICENSE.TXT for details.
+//------------------------------------------------------------------------------
+
+#include "cling/Utils/Validation.h"
+
+#include <assert.h>
+#include <errno.h>
+#ifdef LLVM_ON_WIN32
+# include <Windows.h>
+#else
+#include <fcntl.h>
+# include <unistd.h>
+#endif
+
+
+
+namespace cling {
+  namespace utils {
+
+    static int getNullDevFileDescriptor() {
+#ifdef LLVM_ON_WIN32
+      return 0;
+#else
+      struct FileDescriptor {
+        int FD;
+        const char* file = "/dev/null";
+        FileDescriptor() { FD = open(file, O_WRONLY); }
+        ~FileDescriptor() {
+          close(FD);
+        }
+      };
+      static FileDescriptor nullDev;
+      return nullDev.FD;
+#endif
+    }
+
+    // Checking whether the pointer points to a valid memory location
+    // Used for checking of void* output
+    // Should be moved to earlier stages (ex. IR) in the future
+    bool isAddressValid(const void *P) {
+      if (!P || P == (void *) -1)
+        return false;
+
+#ifdef LLVM_ON_WIN32
+      MEMORY_BASIC_INFORMATION MBI;
+      if (!VirtualQuery(P, &MBI, sizeof(MBI)))
+        return false;
+      if (MBI.State != MEM_COMMIT)
+        return false;
+      return true;
+#else
+      // There is a POSIX way of finding whether an address can be accessed for
+      // reading: write() will return EFAULT if not.
+      int NBytes = write(getNullDevFileDescriptor(), P, 1/*byte*/);
+      if (NBytes != 1) {
+        assert(errno == EFAULT && "unexpected pipe write error");
+        return false;
+      }
+      return true;
+#endif
+    }
+  }
+}