[llvm-commits] [PATCH] Annotate BumpPtrAllocator for MemorySanitizer

[Evgeniy Stepanov]

Hi kcc,

This change helps MSan produce correct "Uninitialised value was created by" stack traces.
Declaration of __msan_allocated_memory is there so that we don't depend on msan_interface.h header from compiler-rt. Alternatively, we could make a copy of that header somewhere in LLVM tree.

http://llvm-reviews.chandlerc.com/D336

Files:
  lib/Support/Allocator.cpp

Index: lib/Support/Allocator.cpp
===================================================================
--- lib/Support/Allocator.cpp
+++ lib/Support/Allocator.cpp
@@ -84,6 +84,13 @@
   End = ((char*)CurSlab) + CurSlab->Size;
 }
 
+#if defined(__has_feature) && __has_feature(memory_sanitizer)
+extern "C" void __msan_allocated_memory(void* data, size_t size);
+# define MSAN_ALLOCATED_MEMORY(p, s) __msan_allocated_memory(p, s)
+#else
+# define MSAN_ALLOCATED_MEMORY(p, s)
+#endif
+
 /// Allocate - Allocate space at the specified alignment.
 ///
 void *BumpPtrAllocator::Allocate(size_t Size, size_t Alignment) {
@@ -102,6 +109,7 @@
   // Check if we can hold it.
   if (Ptr + Size <= End) {
     CurPtr = Ptr + Size;
+    MSAN_ALLOCATED_MEMORY(Ptr, Size);
     return Ptr;
   }
 
@@ -117,14 +125,16 @@
 
     Ptr = AlignPtr((char*)(NewSlab + 1), Alignment);
     assert((uintptr_t)Ptr + Size <= (uintptr_t)NewSlab + NewSlab->Size);
+    MSAN_ALLOCATED_MEMORY(Ptr, Size);
     return Ptr;
   }
 
   // Otherwise, start a new slab and try again.
   StartNewSlab();
   Ptr = AlignPtr(CurPtr, Alignment);
   CurPtr = Ptr + Size;
   assert(CurPtr <= End && "Unable to allocate memory!");
+  MSAN_ALLOCATED_MEMORY(Ptr, Size);
   return Ptr;
 }
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