Vendor import of clang trunk r300422:vendor/clang/clang-trunk-r300422

https://llvm.org/svn/llvm-project/cfe/trunk@300422

1 files changed, 16 insertions, 8 deletions

diff --git a/include/clang/Basic/AddressSpaces.h b/include/clang/Basic/AddressSpaces.h
index 63df61bedbc6..0ec5aafd64b6 100644
--- a/include/clang/Basic/AddressSpaces.h
+++ b/include/clang/Basic/AddressSpaces.h
@@ -20,24 +20,32 @@ namespace clang {
 
 namespace LangAS {
 
-/// \brief Defines the set of possible language-specific address spaces.
+/// \brief Defines the address space values used by the address space qualifier
+/// of QualType.
 ///
-/// This uses a high starting offset so as not to conflict with any address
-/// space used by a target.
 enum ID {
-  Offset = 0x7FFF00,
-
-  opencl_global = Offset,
+  // The default value 0 is the value used in QualType for the the situation
+  // where there is no address space qualifier. For most languages, this also
+  // corresponds to the situation where there is no address space qualifier in
+  // the source code, except for OpenCL, where the address space value 0 in
+  // QualType represents private address space in OpenCL source code.
+  Default = 0,
+
+  // OpenCL specific address spaces.
+  opencl_global,
   opencl_local,
   opencl_constant,
   opencl_generic,
 
+  // CUDA specific address spaces.
   cuda_device,
   cuda_constant,
   cuda_shared,
 
-  Last,
-  Count = Last-Offset
+  // This denotes the count of language-specific address spaces and also
+  // the offset added to the target-specific address spaces, which are usually
+  // specified by address space attributes __attribute__(address_space(n))).
+  Count
 };
 
 /// The type of a lookup table which maps from language-specific address spaces