Clarify -fcheck-memory-usage

From-SVN: r26057

gcc/ChangeLog

+Mon Mar 29 15:11:10 1999  Craig Burley  <craig@jcb-sc.com>
+
+	* invoke.texi (Code Gen Options): Attempt to clarify
+	-fcheck-memory-usage.  Minor edits to -fprefix-function-name.
+
 Mon Mar 29 20:52:47 1999  J"orn Rennecke <amylaar@cygnus.co.uk>
 
 	* loop.c (maybe_eliminate_biv): For libcalls that set a giv, skip to

gcc/invoke.texi

@@ -6060,17 +6060,22 @@ Generate extra code to check each memory access.  GNU CC will generate
 code that is suitable for a detector of bad memory accesses such as
 @file{Checker}.
 
-You must also specify this option when you compile functions you call that
-have side effects.  If you do not, you may get erroneous messages from
-the detector.  Normally,  you should compile all your code with this option.
+Normally, you should compile all, or none, of your code with this option.
+
+If you do mix code compiled with and without this option,
+you must ensure that all code that has side effects
+and that is called by code compiled with this option
+is, itself, compiled with this option.
+If you do not, you might get erroneous messages from the detector.
+
 If you use functions from a library that have side-effects (such as
-@code{read}), you may not be able to recompile the library and
+@code{read}), you might not be able to recompile the library and
 specify this option.  In that case, you can enable the
 @samp{-fprefix-function-name} option, which requests GNU CC to encapsulate
 your code and make other functions look as if they were compiled with
 @samp{-fcheck-memory-usage}.  This is done by calling ``stubs'',
 which are provided by the detector.  If you cannot find or build
-stubs for every function you call, you may have to specify
+stubs for every function you call, you might have to specify
 @samp{-fcheck-memory-usage} without @samp{-fprefix-function-name}.
 
 If you specify this option, you can not use the @code{asm} or
@@ -6095,7 +6100,7 @@ These calls would be similar to those done in the stubs described above.
 Request GNU CC to add a prefix to the symbols generated for function names.
 GNU CC adds a prefix to the names of functions defined as well as
 functions called.  Code compiled with this option and code compiled
-without the option can't be linked together, unless or stubs are used.
+without the option can't be linked together, unless stubs are used.
 
 If you compile the following code with @samp{-fprefix-function-name}
 @example
@@ -6104,7 +6109,6 @@ void
 foo (int a)
 @{
   return bar (a + 5);
-
 @}
 @end example