Clarify generalize offset proposal

List register, composite and implicit location storage as examples of
arbitrary sized storage. Addresses issue ccoutant#65.

Add transition paragraph as proposed in issue ccoutant#66.

Correct section reference in the editorial part.

Clarify address space and memory space proposals.

010-generalize-offsetting.txt

@@ -32,17 +32,19 @@ address integral type value would be required. Keeping a separation of location
 description operations and arithmetic operations avoids this semantic
 complexity.
 
+The offset operators are designed to address four specific problems.
+
 The offset operations can operate on location storage of any size. For example,
-implicit location storage could be any number of bits in size. It is simpler to
-define offsets that exceed the size of the location storage as being an
-evaluation error, than having to force an implementation to support potentially
-infinite precision offsets to allow it to correctly track a series of positive
-and negative offsets that may transiently overflow or underflow, but end up in
-range. This is simple for the arithmetic operations as they are defined in
-terms of two's compliment arithmetic on a base type of a fixed size. Therefore,
-the offset operation define that integer overflow is ill-formed. This is in
-contrast to the DW_OP_plus, DW_OP_plus_uconst, and DW_OP_minus arithmetic
-operations which define that it causes wrap-around.
+register, composite, and implicit location storage could be any number of bits
+in size. It is simpler to define offsets that exceed the size of the location
+storage as being an evaluation error, than having to force an implementation to
+support potentially infinite precision offsets to allow it to correctly track a
+series of positive and negative offsets that may transiently overflow or
+underflow, but end up in range. This is simple for the arithmetic operations as
+they are defined in terms of two's compliment arithmetic on a base type of a
+fixed size. Therefore, the offset operation defines that integer overflow is
+ill-formed. This is in contrast to the DW_OP_plus, DW_OP_plus_uconst, and
+DW_OP_minus arithmetic operations which define that it causes wrap-around.
 
 Having the offset operations allows DW_OP_push_object_address to push a
 location description that may be in a register, or be an implicit value. The

013-generalize-address-spaces.txt

@@ -15,10 +15,15 @@ that can only be put on complete objects, such as a variable. That makes it only
 suitable for describing an entity (such as variable or subprogram code) that is
 in a single kind of memory.
 
-Therefore, AMDGPU uses the DWARF concept of address spaces. For example, a
-variable may be allocated in a register that is partially spilled to the call
-stack which is in the private address space, and partially spilled to the local
-address space.
+AMDGPU uses multiple address spaces. For example, a variable may be allocated in
+a register that is partially spilled to the call stack which is in the private
+address space, and partially spilled to the local address space. DWARF mentions
+address spaces, for example as an argument to the DW_OP_xderef* operations. A
+new section that defines address classes is added.
+
+A new attribute DW_AT_address_space is added to pointer and reference types.
+This allows the compiler to specify which address space is being used to
+represent the pointer or reference type.
 
 DWARF 5 uses the concept of an address in many expression operations but does
 not define how it relates to address spaces. For example,

022-memory-spaces.txt

@@ -3,11 +3,12 @@ Part 18: Support for Source Language Memory Spaces
 PROBLEM DESCRIPTION
 
 AMDGPU supports languages, such as OpenCL, that define source language memory
-classes. Support is added to define language specific memory spaces so they
-can be used in a consistent way by consumers.
+classes. Support is added to define language specific memory spaces so they can
+be used in a consistent way by consumers.
 
-Support for using memory spaces in defining source language types and data
-object allocation is also added.
+A new attribute DW_AT_memory_space is added to support using memory spaces in
+defining source language pointer and reference types and data object
+allocation.
 
 PROPOSAL