VHPI: add initial minimal implementation

Minimal implementation of VHPI provides library loading and
error support. Calling most vhpi_* functions will raise a
VHPI error condition.

Incorporates VHPI thunks into libghdlvpi for linking.

2 files changed, 22 insertions, 3 deletions

diff --git a/doc/using/InvokingGHDL.rst b/doc/using/InvokingGHDL.rst
index 1b5b144e6..29f5e1681 100644
--- a/doc/using/InvokingGHDL.rst
+++ b/doc/using/InvokingGHDL.rst
@@ -661,10 +661,10 @@ Make a local copy of an existing library. This is very useful if you want to add
 
 .. _VPI_build_commands:
 
-VPI build commands
-==================
+VPI/VHPI build commands
+=======================
 
-These commands simplify the compile and the link of a user vpi module. They are all wrappers: the arguments are in fact a
+These commands simplify the compile and the link of a user VPI or VHPI module. They are all wrappers: the arguments are in fact a
 whole command line that is executed with additional switches. Currently a unix-like compiler (like `cc`, `gcc` or `clang`)
 is expected: the additional switches use their syntax. The only option is `-v` which displays the command before its
 execution.
diff --git a/doc/using/Simulation.rst b/doc/using/Simulation.rst
index 807a634e2..6f062a95d 100644
--- a/doc/using/Simulation.rst
+++ b/doc/using/Simulation.rst
@@ -161,6 +161,25 @@ Here is the list of the most useful options. For further info, see :ref:`DEV:Deb
 
   Trace vpi calls. Trace is printed to :file:`FILENAME` if provided, otherwise to stdout.
 
+.. option:: --vhpi=<FILENAME>[:<ENTRYPOINT>]
+
+  Load VHPI library. This option can be used multiple times to load different libraries.
+
+  If an ``ENTRYPOINT`` registration function is provided, it will be called.
+  Otherwise, any registration functions in the ``vhpi_startup_routines`` array in the library will be called:
+
+  .. code-block:: c
+
+    void (*vhpi_startup_routines[])() = {
+      register_foreign_app,
+      register_foreign_func,
+      0
+    };
+
+.. option:: --vhpi-trace[=<FILENAME>]
+
+  Trace vhpi calls. Trace is printed to :file:`FILENAME` if provided, otherwise to stdout.
+
 .. option:: --help
 
   Display a short description of the options accepted by the runtime library.