Add more directives to benchmark input files

This patch adds some more directives to the benchmark inputs file,
moving functionality from the Makefile and making the code generation
script a bit cleaner.  The function argument and return types that
were earlier added as variables in the makefile and passed to the
script via command line arguments are now the 'args' and 'ret'
directive respectively.  'args' should be a colon separated list of
argument types (skipped if the function doesn't accept any arguments)
and 'ret' should be the return type.

Additionally, an 'includes' directive may have a comma separated list
of headers to include in the source.  For example, the pow input file
now looks like this:

42.0, 42.0
1.0000000000000020, 1.5

I did this to unclutter the benchtests Makefile a bit and eventually
eliminate dependency of the tests on the Makefile and have tests
depend on their respective include files only.

1 files changed, 18 insertions, 17 deletions

diff --git a/benchtests/README b/benchtests/README
index 045b7a673d..5faca53511 100644
--- a/benchtests/README
+++ b/benchtests/README
@@ -40,23 +40,24 @@ one to add `foo' to the bench tests:
 
 - Append the function name to the bench variable in the Makefile.
 
-- Define foo-ARGLIST as a colon separated list of types of the input
-  arguments.  Use `void' if function does not take any inputs.  Put in quotes
-  if the input argument is a pointer, e.g.:
-
-     malloc-ARGLIST: "void *"
-
-- Define foo-RET as the type the function returns.  Skip if the function
-  returns void.  One could even skip foo-ARGLIST if the function does not
-  take any inputs AND the function returns void.
-
-- Make a file called `foo-inputs` with one input value per line, an input
-  being a comma separated list of arguments to be passed into the function.
-  See pow-inputs for an example.
-
-  The script that parses the -inputs file treats lines beginning with a single
-  `#' as comments.  Lines beginning with two hashes `##' are treated specially
-  as `directives'.
+- Make a file called `foo-inputs` to provide the definition and input for the
+  function.  The file should have some directives telling the parser script
+  about the function and then one input per line.  Directives are lines that
+  have a special meaning for the parser and they begin with two hashes '##'.
+  The following directives are recognized:
+
+  - args: This should be assigned a colon separated list of types of the input
+    arguments.  This directive may be skipped if the function does not take any
+    inputs.
+  - ret: This should be assigned the type that the function returns.  This
+    directive may be skipped if the function does not return a value.
+  - includes: This should be assigned a comma separated list of headers that
+    need to be included to provide declarations for the function and types it
+    may need.
+  - name: See following section for instructions on how to use this directive.
+
+  Lines beginning with a single hash '#' are treated as comments.  See
+  pow-inputs for an example of an input file.
 
 Multiple execution units per function:
 =====================================