Merge branch 'master' of darcs.haskell.org:/home/darcs/ghc

4 files changed, 69 insertions, 17 deletions

diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml
index d670cb91a9..bc1c228e36 100644
--- a/docs/users_guide/flags.xml
+++ b/docs/users_guide/flags.xml
@@ -511,6 +511,12 @@
             <entry><option>-fno-break-on-error</option></entry>
           </row>
           <row>
+            <entry><option>-fghci-hist-size=<replaceable>n</replaceable></option></entry>
+            <entry><link linkend="ghci-debugger">Set the number of entries GHCi keeps for <literal>:history</literal></link></entry>
+            <entry>dynamic</entry>
+            <entry><option>(default is 50)</option></entry>
+          </row>
+          <row>
             <entry><option>-fprint-evld-with-show</option></entry>
             <entry><link linkend="breakpoints">Enable usage of Show instances in <literal>:print</literal></link></entry>
             <entry>dynamic</entry>
diff --git a/docs/users_guide/ghci.xml b/docs/users_guide/ghci.xml
index 3d1aecc2fb..9e8ea2f0d1 100644
--- a/docs/users_guide/ghci.xml
+++ b/docs/users_guide/ghci.xml
@@ -662,7 +662,7 @@ Prelude>
       an attempt to distinguish it from the new <literal>T</literal>,
       which is displayed as simply <literal>T</literal>.</para>
 
-    <para>Class and type-family instance declarations are simply added to the list of available isntances, with one
+    <para>Class and type-family instance declarations are simply added to the list of available instances, with one
     exception. Since type-family instances are not permitted to overlap, but you might want to re-define one,
     a type-family instance <emphasis>replaces</emphasis> any earlier type instance with an identical left hand side.
     (See <xref linkend="type-families"/>.)</para>
@@ -1715,8 +1715,7 @@ a :: a
       <para>The history is only available when
         using <literal>:trace</literal>; the reason for this is we found that
         logging each breakpoint in the history cuts performance by a factor of
-        2 or more.  GHCi remembers the last 50 steps in the history (perhaps in
-        the future we'll make this configurable).</para>
+        2 or more.  By default, GHCi remembers the last 50 steps in the history, but this can be changed with the <option>-fghci-hist-size=<replaceable>n</replaceable></option><indexterm><primary><option>&ndash;fghci-hist-size</option></primary></indexterm> option).</para>
     </sect2>
 
     <sect2 id="ghci-debugger-exceptions">
@@ -2381,10 +2380,12 @@ Prelude> :. cmds.ghci
           <indexterm><primary><literal>:history</literal></primary></indexterm>
         </term>
 	<listitem>
-	  <para>Display the history of evaluation steps.  With a number,
-            displays that many steps (default: 20).  For use with
-            <literal>:trace</literal>; see <xref
-              linkend="tracing" />.</para>
+	  <para>Display the history of evaluation steps.  With a
+	  number, displays that many steps (default: 20).  For use
+	  with <literal>:trace</literal>; see <xref linkend="tracing"
+	  />.  To set the number of history entries stored by GHCi,
+	  use
+	  <option>-fghci-hist-size=<replaceable>n</replaceable></option>.</para>
 	</listitem>
       </varlistentry>
 
diff --git a/docs/users_guide/glasgow_exts.xml b/docs/users_guide/glasgow_exts.xml
index 3dafb98e62..1bbfaecc4b 100644
--- a/docs/users_guide/glasgow_exts.xml
+++ b/docs/users_guide/glasgow_exts.xml
@@ -9938,24 +9938,17 @@ r) ->
 
 <sect1 id="special-ids">
 <title>Special built-in functions</title>
-<para>GHC has a few built-in functions with special behaviour.  These
-are now described in the module <ulink
-url="&libraryGhcPrimLocation;/GHC-Prim.html"><literal>GHC.Prim</literal></ulink>
-in the library documentation.
+<para>GHC has a few built-in functions with special behaviour.
 In particular:
 <itemizedlist>
 <listitem><para>
-<ulink url="&libraryGhcPrimLocation;/GHC-Prim.html#v%3Ainline"><literal>inline</literal></ulink>
+<ulink url="&libraryGhcPrimLocation;/GHC-Exts.html#v%3Ainline"><literal>inline</literal></ulink>
 allows control over inlining on a per-call-site basis.
 </para></listitem>
 <listitem><para>
-<ulink url="&libraryGhcPrimLocation;/GHC-Prim.html#v%3Alazy"><literal>lazy</literal></ulink>
+<ulink url="&libraryGhcPrimLocation;/GHC-Exts.html#v%3Alazy"><literal>lazy</literal></ulink>
 restrains the strictness analyser.
 </para></listitem>
-<listitem><para>
-<ulink url="&libraryGhcPrimLocation;/GHC-Prim.html#v%3AunsafeCoerce%23"><literal>unsafeCoerce#</literal></ulink>
-allows you to fool the type checker.
-</para></listitem>
 </itemizedlist>
 </para>
 </sect1>
diff --git a/docs/users_guide/safe_haskell.xml b/docs/users_guide/safe_haskell.xml
index dc07b89bb8..8b777bbed2 100644
--- a/docs/users_guide/safe_haskell.xml
+++ b/docs/users_guide/safe_haskell.xml
@@ -44,6 +44,16 @@
   </itemizedlist>
   </para>
 
+  <para>
+  Safe Haskell, however, <emphasis>does not offer</emphasis> compilation
+  safety. During compilation time it is possible for arbitrary processes to be
+  launched, using for example the <link linkend="pre-processor">custom
+    pre-processor</link> flag. This can be manipulated to either compromise a
+  users system at compilation time, or to modify the source code just before
+  compilation to try to alter set Safe Haskell flags. This is discussed further
+  in section <xref linkend="safe-compilation"/>.
+  </para>
+
   <sect2 id="safe-use-cases">
     <title>Uses of Safe Haskell</title>
     <indexterm><primary>safe haskell uses</primary></indexterm>
@@ -722,6 +732,48 @@
     </variablelist>
   </sect2>
 
+  <sect2 id="safe-compilation">
+    <title>Safe Compilation</title>
+    <indexterm><primary>safe compilation</primary></indexterm>
+
+    <para>
+    GHC includes a variety of flags that allow arbitrary processes to be run at
+    compilation time. One such example is the <link
+      linkend="pre-processor">custom pre-processor</link> flag. Another is the
+    ability of Template Haskell to execute Haskell code at compilation time,
+    including IO actions. Safe Haskell <emphasis>does not address this
+      danger</emphasis> (although, Template Haskell is a disallowed feature).
+    </para>
+
+    <para>
+    Due to this, it is suggested that when compiling untrusted source code that
+    has had no manual inspection done, the following precautions be taken:
+    <itemizedlist>
+      <listitem>Compile in a sandbox, such as a chroot or similar container
+        technology. Or simply as a user with very reduced system
+        access.</listitem>
+      <listitem>Compile untrusted code with the <option>-XSafe</option> flag
+        being specified on the command line. This will ensure that modifications
+        to the source being compiled can't disable the use of the Safe Language
+        as the command line flag takes precedence over a source level
+        pragma.</listitem>
+      <listitem>Ensure that all untrusted code is imported as a
+        <link linkend="safe-imports">safe import</link><emphasis> and</emphasis>
+        that the <link linkend="safe-package-trust"><option>-fpackage-trust</option></link>
+        flag is used with packages from untrusted sources being marked as
+        untrusted.</listitem>
+    </itemizedlist>
+    </para>
+
+    <para>
+    There is a more detailed discussion of the issues involved in compilation
+    safety and some potential solutions on the <ulink
+      url="http://hackage.haskell.org/trac/ghc/wiki/SafeHaskell/SafeCompilation">GHC
+      Wiki</ulink>.
+    </para>
+
+  </sect2>
+
 </sect1>
 
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