Add the code of generated predicates and logic functions as a global
annotation above their declaration in the generated C code.

This commit adds a Here inliner to Logic_normalizer, which specialises
labelled logic functions that are called somewhere exclusively with Here
labels.

If a function is translated multiple times with the same profile but
with different return types, then things get mixed up.
The problem is outlined in detail in the previous commit.

The solution is to take into account the return type of the generated
functions.

This commit also includes a cosmetic overhaul of the memoisation code.

This commit complements a5caf8c1

Instead of a dedicated file tests/arith/sign_rational.c, merge its
contents into tests/arith/functions.c.

- always remove FC's internal attribute everywhere before deciding whether
  a cast is needed.
- ACSL and C decisions to cast are similar
- only unroll type for checking equality. If a cast is needed, keep
  typedef (if any) as target

- The global variable is now a Frama-C built-in and is not monitored;
- The `varinfo` for the variable, retrieved in module `Prepare_ast` is
  now exposed;
- The variable is added to every generated code so that it can be used
  by a later analysis of E-ACSL.

Avoid warning about missing proto during typechecking.
Also changes a warning into an error, and improves the error message.

Basile Desloges authored 5 years ago and Julien Signoles committed 5 years ago

A `file` parameter is added before `line`, and the `char *` parameters
have been converted to `const char *`.