1 files changed, 32 insertions, 8 deletions
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_local_address_space_view.h b/compiler-rt/lib/sanitizer_common/sanitizer_local_address_space_view.h
index f9507c701e2..ec1847abc53 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_local_address_space_view.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_local_address_space_view.h
@@ -31,18 +31,42 @@
 
 namespace __sanitizer {
 struct LocalAddressSpaceView {
-  // Load memory `sizeof(T) * num_elements` bytes of memory
-  // from the target process (always local for this implementation)
-  // starting at address `target_address`. The local copy of
-  // this memory is returned as a pointer. It is guaranteed that
+  // Load memory `sizeof(T) * num_elements` bytes of memory from the target
+  // process (always local for this implementation) starting at address
+  // `target_address`. The local copy of this memory is returned as a pointer.
+  // The caller should not write to this memory. The behaviour when doing so is
+  // undefined. Callers should use `LoadWritable()` to get access to memory
+  // that is writable.
   //
-  // * That the function will always return the same value
-  //   for a given set of arguments.
-  // * That the memory returned is writable and that writes will persist.
+  // The lifetime of loaded memory is implementation defined.
+  template <typename T>
+  static const T *Load(const T *target_address, uptr num_elements = 1) {
+    // The target address space is the local address space so
+    // nothing needs to be copied. Just return the pointer.
+    return target_address;
+  }
+
+  // Load memory `sizeof(T) * num_elements` bytes of memory from the target
+  // process (always local for this implementation) starting at address
+  // `target_address`. The local copy of this memory is returned as a pointer.
+  // The memory returned may be written to.
+  //
+  // Writes made to the returned memory will be visible in the memory returned
+  // by subsequent `Load()` or `LoadWritable()` calls provided the
+  // `target_address` parameter is the same. It is not guaranteed that the
+  // memory returned by previous calls to `Load()` will contain any performed
+  // writes.  If two or more overlapping regions of memory are loaded via
+  // separate calls to `LoadWritable()`, it is implementation defined whether
+  // writes made to the region returned by one call are visible in the regions
+  // returned by other calls.
+  //
+  // Given the above it is recommended to load the largest possible object
+  // that requires modification (e.g. a class) rather than individual fields
+  // from a class to avoid issues with overlapping writable regions.
   //
   // The lifetime of loaded memory is implementation defined.
   template <typename T>
-  static T *Load(T *target_address, uptr num_elements = 1) {
+  static T *LoadWritable(T *target_address, uptr num_elements = 1) {
     // The target address space is the local address space so
     // nothing needs to be copied. Just return the pointer.
     return target_address;