fix(examples/vhdl/external_buffer): use the reference C sources

* add sigabrt.md

examples/vhdl/external_buffer/run.py

@@ -28,8 +28,10 @@
 from vunit import VUnit
 from os import popen
 from os.path import join, dirname
+import inspect
 
 src_path = join(dirname(__file__), 'src')
+ext_srcs = join(dirname(inspect.getfile(VUnit)), 'vhdl', 'data_types', 'src', 'external')
 
 # Compile C applications to an objects
 c_iobj = join(src_path, 'imain.o')
@@ -38,13 +40,15 @@
 print(popen(' '.join([
     'gcc', '-fPIC',
     '-DTYPE=int32_t',
+    '-I', ext_srcs,
     '-c', join(src_path, 'main.c'),
     '-o', c_iobj
 ])).read())
 
 print(popen(' '.join([
     'gcc', '-fPIC',
     '-DTYPE=uint8_t',
+    '-I', ext_srcs,
     '-c', join(src_path, 'main.c'),
     '-o', c_bobj
 ])).read())
@@ -58,8 +62,8 @@
 
 # Add the C object to the elaboration of GHDL
 for tb in lib.get_test_benches(pattern='*tb_ext*', allow_empty=False):
-    tb.set_sim_option('ghdl.elab_flags', ['-Wl,' + c_bobj], overwrite=True)
+    tb.set_sim_option('ghdl.elab_flags', ['-Wl,' + c_bobj, '-Wl,-Wl,--version-script=' + join(ext_srcs, 'grt.ver')], overwrite=True)
 for tb in lib.get_test_benches(pattern='*tb_ext*_integer*', allow_empty=False):
-    tb.set_sim_option('ghdl.elab_flags', ['-Wl,' + c_iobj], overwrite=True)
+    tb.set_sim_option('ghdl.elab_flags', ['-Wl,' + c_iobj, '-Wl,-Wl,--version-script=' + join(ext_srcs, 'grt.ver')], overwrite=True)
 
 vu.main()

examples/vhdl/external_buffer/sigabrt.md

@@ -0,0 +1,26 @@
+When VHDL 1993 is used, the simulation is terminated with an `abort`, which prevents the user from running post-checks.
+These are some snippets to test it. See https://github.com/VUnit/vunit/pull/469#issuecomment-485723516.
+
+``` python
+https://bugs.python.org/issue12423
+def handler(signum, frame):
+    print('Signal handler called with signal', signum)
+import signal
+signal.signal(signal.SIGABRT, handler)
+import os
+os.abort()
+```
+
+``` c
+#include <signal.h>
+
+void sigabrtHandler(int sig_num)
+{
+    // Reset handler to catch SIGINT next time. Refer http://en.cppreference.com/w/c/program/signal
+    signal(SIGABRT, sigabrtHandler);
+    printf("\nSIGABRT caught!\n");
+    fflush(stdout);
+}
+
+signal(SIGABRT, sigabrtHandler);
+```

examples/vhdl/external_buffer/src/main.c

@@ -21,10 +21,8 @@ or tb_ext_integer_vector.vhd
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include "vhpidirect_user.h"
 
-extern int ghdl_main (int argc, char **argv);
-
-uint8_t *D[1];
 const uint32_t length = 5;
 
 /*
@@ -34,7 +32,7 @@ const uint32_t length = 5;
  [2/3, 3/3), while incrementing each value by two.
 */
 static void exit_handler(void) {
-  uint i, j, z, k;
+  unsigned i, j, z, k;
   TYPE expected, got;
   k = 0;
   for (j=0; j<3; j++) {
@@ -80,43 +78,3 @@ int main(int argc, char **argv) {
   // Start the simulation
   return ghdl_main(argc, argv);
 }
-
-// External string/byte_vector through access (mode = extacc)
-
-void set_string_ptr(uint8_t id, uint8_t *p) {
-  D[id] = p;
-}
-
-uintptr_t get_string_ptr(uint8_t id) {
-  return (uintptr_t)D[id];
-}
-
-// External string/byte_vector through functions (mode = extfnc)
-
-void write_char(uint8_t id, uint32_t i, uint8_t v ) {
-  D[id][i] = v;
-}
-
-uint8_t read_char(uint8_t id, uint32_t i) {
-  return D[id][i];
-}
-
-// External integer_vector through access (mode = extacc)
-
-void set_intvec_ptr(uint8_t id, uintptr_t *p) {
-  D[id] = (uint8_t*)p;
-}
-
-uintptr_t get_intvec_ptr(uint8_t id) {
-  return (uintptr_t)D[id];
-}
-
-// External integer_vector through functions (mode = extfnc)
-
-void write_integer(uint8_t id, uint32_t i, int32_t v) {
-  ((int32_t*)D[id])[i] = v;