From ea2d8780e9c78628fe5e3312ca4c17c054156c83 Mon Sep 17 00:00:00 2001
From: Evgeniy Stepanov <eugeni.stepanov@gmail.com>
Date: Thu, 31 Jan 2013 09:58:59 +0000
Subject: [PATCH] Annotate BumpPtrAllocator for MemorySanitizer.

This change adds MemorySanitizer annotations to BumpPtrAllocator to
improve report quality.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174051 91177308-0d34-0410-b5e6-96231b3b80d8
---
 cmake/config-ix.cmake              |  1 +
 include/llvm/Config/config.h.cmake |  3 +++
 include/llvm/Support/Compiler.h    | 18 ++++++++++++++++++
 lib/Support/Allocator.cpp          |  7 +++++++
 4 files changed, 29 insertions(+)

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index c625b871e4c..a313e9cbb03 100755
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -54,6 +54,7 @@ check_include_file(ndir.h HAVE_NDIR_H)
 if( NOT PURE_WINDOWS )
   check_include_file(pthread.h HAVE_PTHREAD_H)
 endif()
+check_include_file(sanitizer/msan_interface.h HAVE_SANITIZER_MSAN_INTERFACE_H)
 check_include_file(setjmp.h HAVE_SETJMP_H)
 check_include_file(signal.h HAVE_SIGNAL_H)
 check_include_file(stdint.h HAVE_STDINT_H)
diff --git a/include/llvm/Config/config.h.cmake b/include/llvm/Config/config.h.cmake
index 94870834313..b0b81042051 100644
--- a/include/llvm/Config/config.h.cmake
+++ b/include/llvm/Config/config.h.cmake
@@ -468,6 +468,9 @@
 /* Define to 1 if the system has the type `u_int64_t'. */
 #cmakedefine HAVE_U_INT64_T ${HAVE_U_INT64_T}
 
+/* Define to 1 if you have the <sanitizer/msan_interface.h> header file. */
+#cmakedefine HAVE_SANITIZER_MSAN_INTERFACE_H ${HAVE_SANITIZER_MSAN_INTERFACE_H}
+
 /* Define to 1 if you have the <valgrind/valgrind.h> header file. */
 #cmakedefine HAVE_VALGRIND_VALGRIND_H ${HAVE_VALGRIND_VALGRIND_H}
 
diff --git a/include/llvm/Support/Compiler.h b/include/llvm/Support/Compiler.h
index 96af756dde3..36539f6d346 100644
--- a/include/llvm/Support/Compiler.h
+++ b/include/llvm/Support/Compiler.h
@@ -15,6 +15,8 @@
 #ifndef LLVM_SUPPORT_COMPILER_H
 #define LLVM_SUPPORT_COMPILER_H
 
+#include "llvm/Config/config.h"
+
 #ifndef __has_feature
 # define __has_feature(x) 0
 #endif
@@ -293,4 +295,20 @@
 # define LLVM_FUNCTION_NAME __func__
 #endif
 
+/// \macro LLVM_ENABLE_MSAN_ANNOTATIONS
+/// \brief Are MemorySanitizer annotations available.
+#if defined(HAVE_SANITIZER_MSAN_INTERFACE_H)
+# include <sanitizer/msan_interface.h>
+#else
+# define __msan_allocated_memory(p, size)
+#endif
+
+/// \macro LLVM_MEMORY_SANITIZER_BUILD
+/// \brief Whether LLVM itself is built with MemorySanitizer instrumentation.
+#if __has_feature(memory_sanitizer)
+# define LLVM_MEMORY_SANITIZER_BUILD 1
+#else
+# define LLVM_MEMORY_SANITIZER_BUILD 0
+#endif
+
 #endif
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 28f4e64ac77..b4fdc1e1bc1 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/Allocator.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/Memory.h"
 #include "llvm/Support/Recycler.h"
@@ -102,6 +103,10 @@ void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
   // Check if we can hold it.
   if (Ptr + Size <= End) {
     CurPtr = Ptr + Size;
+    // Update the allocation point of this memory block in MemorySanitizer.
+    // Without this, MemorySanitizer reports for values originating from it will
+    // point to the allocation point of the entire slab.
+    __msan_allocated_memory(Ptr, Size);
     return Ptr;
   }
 
@@ -117,6 +122,7 @@ void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
 
     Ptr = AlignPtr((char*)(NewSlab + 1), Alignment);
     assert((uintptr_t)Ptr + Size <= (uintptr_t)NewSlab + NewSlab->Size);
+    __msan_allocated_memory(Ptr, Size);
     return Ptr;
   }
 
@@ -125,6 +131,7 @@ void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
   Ptr = AlignPtr(CurPtr, Alignment);
   CurPtr = Ptr + Size;
   assert(CurPtr <= End && "Unable to allocate memory!");
+  __msan_allocated_memory(Ptr, Size);
   return Ptr;
 }
 
-- 
2.34.1