invoke.texi: Document that -V will only work for very similar versions of driver...

	* invoke.texi: Document that -V will only work for very similar
	versions of driver and compiler.

From-SVN: r37125

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index af210008cbe8ec11bc934c37f78592a2d64d578c..0f12f3c9189b269355d42b15dd0d3bfe52dd3916 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2000-10-29  Joseph S. Myers  <jsm28@cam.ac.uk>
+
+       * invoke.texi: Document that -V will only work for very similar
+       versions of driver and compiler.
+
 2000-10-29  Neil Booth  <neilb@earthling.net>
 
        * cppmacro.c (_cpp_create_definition): Optimize the case of

diff --git a/gcc/invoke.texi b/gcc/invoke.texi
index ff075cdd838e5a670295ca1ea5b8c585c3468aa2..fff5bb2f6e1d6d24eb86055f9eeafec56a375d76 100644 (file)
--- a/gcc/invoke.texi
+++ b/gcc/invoke.texi
@@ -3948,14 +3948,20 @@ that you originally invoked continues to run and invoke the other
 executables (preprocessor, compiler per se, assembler and linker)
 that do the real work.  However, since no real work is done in the
 driver program, it usually does not matter that the driver program
-in use is not the one for the specified target and version.
+in use is not the one for the specified target.  It is common for the
+interface to the other executables to change incompatibly between
+compiler versions, so unless the version specified is very close to that
+of the driver (for example, @samp{-V 3.0} with a driver program from GCC
+version 3.0.1), use of @samp{-V} may not work; for example, using
+@samp{-V 2.95.2} will not work with a driver program from GCC 3.0.
 
 The only way that the driver program depends on the target machine is
 in the parsing and handling of special machine-specific options.
 However, this is controlled by a file which is found, along with the
 other executables, in the directory for the specified version and
 target machine.  As a result, a single installed driver program adapts
-to any specified target machine and compiler version.
+to any specified target machine, and sufficiently similar compiler
+versions.
 
 The driver program executable does control one significant thing,
 however: the default version and target machine.  Therefore, you can