1.0.41.42: ppc: Documentation and NEWS updates for threading.

[sbcl.git] / doc / manual / efficiency.texinfo

diff --git a/doc/manual/efficiency.texinfo b/doc/manual/efficiency.texinfo
index b6d67fe..6820e77 100644 (file)
--- a/doc/manual/efficiency.texinfo
+++ b/doc/manual/efficiency.texinfo
@@ -4,10 +4,11 @@
 @cindex Efficiency
 
 @menu
 @cindex Efficiency
 
 @menu

-* Slot access::                 
-* Dynamic-extent allocation::   
-* Modular arithmetic::          
-* Miscellaneous Efficiency Issues::  
+* Slot access::
+* Dynamic-extent allocation::
+* Modular arithmetic::
+* Global and Always-Bound variables::
+* Miscellaneous Efficiency Issues::

 @end menu
 
 @node  Slot access
 @end menu
 
 @node  Slot access

@@ -69,7 +70,8 @@ lazily set up during those calls.
 @node  Dynamic-extent allocation
 @comment  node-name,  next,  previous,  up
 @section Dynamic-extent allocation
 @node  Dynamic-extent allocation
 @comment  node-name,  next,  previous,  up
 @section Dynamic-extent allocation

-@cindex Dynamic-extent declaration
+@cindex @code{dynamic-extent} declaration
+@cindex declaration, @code{dynamic-extent}

 
 SBCL has limited support for performing allocation on the stack when a
 variable is declared @code{dynamic-extent}. The @code{dynamic-extent}
 
 SBCL has limited support for performing allocation on the stack when a
 variable is declared @code{dynamic-extent}. The @code{dynamic-extent}

@@ -92,21 +94,31 @@ useful. At present, SBCL implements stack allocation for
 @code{&rest} lists, when these are declared @code{dynamic-extent}.
 
 @item
 @code{&rest} lists, when these are declared @code{dynamic-extent}.
 
 @item

-@code{cons}, @code{list} and @code{list*}, when the result is bound to
-a variable declared @code{dynamic-extent}.
+@findex @cl{cons}
+@findex @cl{list}
+@findex @cl{list*}
+@findex @cl{vector}
+@code{cons}, @code{list}, @code{list*}, and @code{vector} when the
+result is bound to a variable declared @code{dynamic-extent}.

 
 @item
 
 @item

+@findex @cl{make-array}

 simple forms of @code{make-array}, whose result is bound to a variable
 declared @code{dynamic-extent}: stack allocation is possible only if
 simple forms of @code{make-array}, whose result is bound to a variable
 declared @code{dynamic-extent}: stack allocation is possible only if

-the resulting array is one-dimensional, and the call has no keyword
-arguments with the exception of @code{:element-type}.
+the resulting array is known to be both simple and one-dimensional,
+and has a constant @code{:element-type}.

 
 

+@cindex Safety optimization quality

 @strong{Note}: stack space is limited, so allocation of a large vector
 may cause stack overflow. For this reason potentially large vectors,
 which might circumvent stack overflow detection, are stack allocated
 only in zero @code{safety} policies.
 
 @item
 @strong{Note}: stack space is limited, so allocation of a large vector
 may cause stack overflow. For this reason potentially large vectors,
 which might circumvent stack overflow detection, are stack allocated
 only in zero @code{safety} policies.
 
 @item

+@findex @cl{flet}
+@findex @cl{labels}
+@cindex @code{safety} optimization quality
+@cindex optimization quality, @code{safety}

 closures defined with @code{flet} or @code{labels}, with a bound
 @code{dynamic-extent} declaration. Closed-over variables, which are
 assigned to (either inside or outside the closure) are still allocated
 closures defined with @code{flet} or @code{labels}, with a bound
 @code{dynamic-extent} declaration. Closed-over variables, which are
 assigned to (either inside or outside the closure) are still allocated

@@ -120,7 +132,7 @@ user-defined structures when the structure constructor defined using
 call to the constructor is bound to a variable declared
 @code{dynamic-extent}.
 
 call to the constructor is bound to a variable declared
 @code{dynamic-extent}.
 

-@strong{Note:} structures with ``raw'' slots can currently be
+@strong{Note}: structures with ``raw'' slots can currently be

 stack-allocated only on x86 and x86-64.
 
 @item
 stack-allocated only on x86 and x86-64.
 
 @item

@@ -188,7 +200,7 @@ closure, even when the closure is not declared @code{dynamic-extent}.
 @cindex Modular arithmetic
 @cindex Arithmetic, modular
 @cindex Arithmetic, hardware
 @cindex Modular arithmetic
 @cindex Arithmetic, modular
 @cindex Arithmetic, hardware

-
+@findex @cl{logand}

 Some numeric functions have a property: @var{N} lower bits of the
 result depend only on @var{N} lower bits of (all or some)
 arguments. If the compiler sees an expression of form @code{(logand
 Some numeric functions have a property: @var{N} lower bits of the
 result depend only on @var{N} lower bits of (all or some)
 arguments. If the compiler sees an expression of form @code{(logand

@@ -223,6 +235,36 @@ argument. ``Good'' widths are 32 on HPPA, MIPS, PPC, Sparc and x86 and
 64 on Alpha.  While it is possible to support smaller widths as well,
 currently this is not implemented.
 
 64 on Alpha.  While it is possible to support smaller widths as well,
 currently this is not implemented.
 

+@node  Global and Always-Bound variables
+@comment  node-name,  next,  previous,  up
+@section Global and Always-Bound variables
+
+@include macro-sb-ext-defglobal.texinfo
+
+@deffn {Declaration} @sbext{global}
+
+Syntax: @code{(sb-ext:global symbol*)}
+
+Only valid as a global proclamation.
+
+Specifies that the named symbols cannot be proclaimed or locally
+declared @code{special}. Proclaiming an already special or constant
+variable name as @code{global} signal an error. Allows more efficient
+value lookup in threaded environments in addition to expressing
+programmer intention.
+@end deffn
+
+@deffn {Declaration} @sbext{always-bound}
+
+Syntax: @code{(sb-ext:always-bound symbol*)}
+
+Only valid as a global proclamation.
+
+Specifies that the named symbols is always bound. Inhibits @code{makunbound}
+of the named symbols. Proclaiming an unbound symbol as @code{always-bound} signals
+an error. Allows compiler to elide boundness checks from value lookups.
+@end deffn
+

 @node  Miscellaneous Efficiency Issues
 @comment  node-name,  next,  previous,  up
 @section Miscellaneous Efficiency Issues
 @node  Miscellaneous Efficiency Issues
 @comment  node-name,  next,  previous,  up
 @section Miscellaneous Efficiency Issues

@@ -256,6 +298,10 @@ points to keep in mind.
 @itemize
 
 @item
 @itemize
 
 @item

+@findex @cl{let}
+@findex @cl{let*}
+@findex @cl{setq}
+@findex @cl{setf}

 The CMUCL manual doesn't seem to state it explicitly, but Python has a
 mental block about type inference when assignment is involved. Python
 is very aggressive and clever about inferring the types of values
 The CMUCL manual doesn't seem to state it explicitly, but Python has a
 mental block about type inference when assignment is involved. Python
 is very aggressive and clever about inferring the types of values