[Lang] Update and restructure cbuffer spec

specs/language/basic.tex

@@ -124,6 +124,44 @@
 
 \Sec{Name Lookup}{Basic.Lookup}
 
+\Sec{Storage Duration}{Basic.Storage}
+
+\p The storage duration of an object is the portion of the program's execution
+time during which the object exists in memory. An object may have one of the
+following storage durations:
+\begin{itemize}
+\item \textit{static storage duration}
+\item \textit{automatic storage duration}
+\item \textit{program storage duration}
+\item \textit{groupshared storage duration}
+\end{itemize}
+
+\Sub{Static Storage Duration}{Basic.Storage.Static}
+
+\p An object whose name is declared with the \texttt{static} storage specifier
+has \textit{static storage duration}. Such an object is created when the thread
+begins execution and destroyed when the thread ends execution.
+
+\Sub{Automatic Storage Duration}{Basic.Storage.Auto}
+
+\p An object whose name is declared in a block (including function parameters)
+without the \texttt{static} storage specifier has \textit{automatic storage
+duration}. Such an object is created when the block in which it is declared is
+entered and destroyed when the block is exited.
+
+\Sub{Program Storage Duration}{Basic.Storage.Program}
+
+\p An object whose name is declared in a global, namespace, or cbuffer scope
+without the \texttt{static} storage specifier has \textit{program storage
+duration}. Such an object is created when the program begins execution and
+destroyed when the program ends execution.
+
+\Sub{Groupshared Storage Duration}{Basic.Storage.Groupshared}
+
+\p An object whose name is declared with the \texttt{groupshared} storage
+specifier has \textit{groupshared storage duration}. Such an object is created
+when the thread group begins execution and destroyed when the thread group ends.
+
 \Sec{Program and linkage}{Basic.Linkage}
 
 \p A translation unit (\ref{Lex.Translation}) is comprised of a sequence of

specs/language/declarations.tex

@@ -3,30 +3,38 @@
 \p Declarations generally specify how names are to be interpreted. Declarations have the form
 \begin{grammar}
   \define{declaration-seq}\br
-  \textit{declaration}\br
-  \textit{declaration-seq declaration}
+  declaration\br
+  declaration-seq declaration\br
 
   \define{declaration}\br
-  \textit{name-declaration}\br
-  \textit{special-declaration}\br
-  \textit{empty-declaration}
+  name-declaration\br
+  special-declaration\br
 
   \define{name-declaration}\br
-  \textit{variable-declaration}\br
-  \textit{function-declaration}\br
-  \textit{namespace-declaration}\br
-  \textit{record-declaration}\br
-  \textit{template-declaration}\br
-  \textit{type-alias-declaration}\br
-  ...
-  
+  block-declaration\br
+  function-definition\br
+  template-declaration\br
+  namespace-definition\br
+  empty-declaration\br
+  attribute-declaration\br
+  cbuffer-declaration\br
+
   \define{special-declaration}\br
-  \textit{export-declaration-group}\br
-  \textit{cbuffer-declaration-group}\br
-  ...
+  export-declaration-group\br
+  cbuffer-member-declaration\br
+
+  \define{block-declaration}\br
+  simple-declaration\br
+  namespace-alias-definition\br
+  using-declaration\br
+  using-directive\br
+  static\_assert-declaration\br
+  alias-declaration\br
+  opaque-enum-declaration\br
+
+  \define{empty-declaration}\br
+  \terminal{;}
 
-  \define{empty-declaration} \terminal{;}
-
 \end{grammar}
 
 \Sec{Specifiers}{Decl.Spec}
@@ -146,3 +154,41 @@
 \p Functions with \textit{external linkage} can also be declared with an \texttt{export} specifier (\ref{Decl.Spec.Fct}).
 
 \p If a function is part of an \textit{export-declaration-group} then all redeclarations of the same function must also be part on a \textit{export-declaration-group} or be declared with an \texttt{export} specifier (\ref{Decl.Spec.Fct}).
+
+\Sec{Constant Buffer Declarations}{Decl.cbuffer}
+
+\begin{grammar}
+  \define{cbuffer-declaration}\br
+  \terminal{cbuffer} name \opt{resource-binding} \terminal{\{}
+    \opt{cbuffer-member-seq} \terminal {\}}\br
+
+  \define{cbuffer-member-seq}\br
+  cbuffer-member-declaration\br
+  cbuffer-member-seq cbuffer-member-declaration\br
+
+  \define{cbuffer-member-declaration}\br
+  block-declaration\br
+  function-definition\br
+  template-declaration\br
+  empty-declaration
+\end{grammar}
+
+\p A \textit{cbuffer declaration} is declared with the \texttt{cbuffer} keyword.
+The name of the cbuffer declaration does not declare a name, and cannot be
+referenced from within the translation unit, nor is it required to be unique.
+Each cbuffer declaration refers to a unique constant buffer resource
+(\ref{Resources.cnbuf}).
+
+\p Declarations within a cbuffer declaration that declare names, declare their
+names in the scope containing the cbuffer declaration. The cbuffer declaration
+itself does not declare a declaration scope. A cbuffer declaration may not
+contain a \textit{namespace-declaration} or \textit{cbuffer-declaration}.
+\footnote{These declarations were previously allowed in HLSL reference compilers
+but are not supported in this specification.}
+
+\p Variable declarations with program storage duration
+(\ref{Basic.Storage.Program}) in the cbuffer declaration are called
+\textit{shader constants}. Shader constants are implicitly \texttt{const} and
+cannot be modified in program code.\footnote{A future version of this
+specification will likely disallow variable declarations with storage durations
+other than program storage duration in cbuffer declarations.}

specs/language/resources.tex

@@ -665,59 +665,17 @@
 
 \Sec{Constant Buffers}{Resources.cnbuf}
 
-Constant buffers represent resources that contain read-only constant data in a
-well-defined memory layout.
-
-\Sub{Constant Buffer Declaration Block}{Resources.cnbuf.cb}
-
-\p A constant buffer can be declared using the \texttt{cbuffer} specifier.
-
-\begin{grammar}
-  \define{cbuffer-declaration-group}\br
-  \terminal{cbuffer} name \opt{resource-binding} \terminal{\{}
-  \opt{cbuffer-declaration-seq} \terminal {\}}
-
-  \define{cbuffer-declaration-seq}\br
-  \textit{cbuffer-declaration}\br
-  \textit{cbuffer-declaration-seq cbuffer-declaration}
-
-  \define{cbuffer-declaration}\br
-  \textit{variable-declaration}\br
-  \textit{empty-declaration}
-\end{grammar}
-
-\p The name of the \texttt{cbuffer} declaration group cannot be referenced from within the translation unit and is not required to be unique.
-
-\p Variable declarations in the \texttt{cbuffer} declaration group are called \textit{shader constants}.
-
-\p Shader constants can be referenced from anywhere in the translation unit after they are declared by directly using the declaration name. This implies that all shader constants declared in a translation unit must have unique names, even though they might be declared in different \texttt{cbuffer} declaration groups.
-
-\p Variable declarations in the \texttt{cbuffer} declaration group cannot have \texttt{groupshared} or \texttt{static} variable modifiers.
-
-\p Other declarations in the \texttt{cbuffer} declaration group such as
-\textit{namespace-declaration}, \textit{record-declaration} or
-\textit{function-declaration} are not allowed.
-
-\p Nesting of \texttt{cbuffer} declaration groups is not allowed.
-
-\p For example:
-
-\begin{HLSL}
-  cbuffer MyConstants {
-    float4 CameraPos;
-  };
-
-  float4 getCameraPosition() {
-    return CameraPos;
-  }
-\end{HLSL}
+\p Constant buffers represent resources that contain read-only constant data in a
+well-defined memory layout. A constant buffer is declared either as a
+cbuffer-declaration (\ref{Decl.cbuffer}) or as a declaration of Constant Buffer
+Class type (\ref{Resources.cnbuf.cbclass}).
 
 \Sub{Constant Buffer Class}{Resources.cnbuf.cbclass}
 
 \p Another way of declaring constant buffers is by using the
 \texttt{ConstantBuffer<T>} resource class.
 
-\p The template parameter \texttt{T} must be a class type (\ref{Classes}). 
+\p The template parameter \texttt{T} must be a class type (\ref{Classes}).
 
 \begin{HLSL}
   template <typename T>