Report double calls to vpi_release_handle when using VL_DEBUG

include/verilated_vpi.cpp

@@ -56,6 +56,13 @@ constexpr unsigned VL_VPI_LINE_SIZE = 8192;
 
 // Base VPI handled object
 class VerilatedVpio VL_NOT_FINAL {
+    // CONSTANTS
+    /// Magic value stored in front of object to detect double free etc
+    /// Must be odd, as aligned pointer can never be odd
+#ifdef VL_DEBUG
+    static constexpr vluint32_t activeMagic() { return 0xfeed100f; }
+#endif
+
     // MEM MANGLEMENT
     static VL_THREAD_LOCAL vluint8_t* t_freeHead;
 
@@ -73,14 +80,27 @@ public:
         if (VL_LIKELY(t_freeHead)) {
             vluint8_t* newp = t_freeHead;
             t_freeHead = *(reinterpret_cast<vluint8_t**>(newp));
+#ifdef VL_DEBUG
+            *(reinterpret_cast<vluint32_t*>(newp)) = activeMagic();
+#endif
             return newp + 8;
         }
         // +8: 8 bytes for next
         vluint8_t* newp = reinterpret_cast<vluint8_t*>(::operator new(chunk + 8));
+#ifdef VL_DEBUG
+        *(reinterpret_cast<vluint32_t*>(newp)) = activeMagic();
+#endif
         return newp + 8;
     }
     static void operator delete(void* obj, size_t /*size*/)VL_MT_SAFE {
         vluint8_t* oldp = (static_cast<vluint8_t*>(obj)) - 8;
+#ifdef VL_DEBUG
+        if (VL_UNLIKELY(*(reinterpret_cast<vluint32_t*>(oldp)) != activeMagic())) {
+            VL_FATAL_MT(__FILE__, __LINE__, "",
+                        "vpi_release_handle() called on same object twice, or on non-Verilator "
+                        "VPI object");
+        }
+#endif
         *(reinterpret_cast<void**>(oldp)) = t_freeHead;
         t_freeHead = oldp;
     }
@@ -2003,9 +2023,8 @@ PLI_INT32 vpi_chk_error(p_vpi_error_info error_info_p) {
 }
 
 PLI_INT32 vpi_free_object(vpiHandle object) {
-    VerilatedVpiImp::assertOneCheck();
-    _VL_VPI_ERROR_RESET();
-    return vpi_release_handle(object);  // Deprecated
+    // vpi_free_object is IEEE deprecated, use vpi_release_handle
+    return vpi_release_handle(object);
 }
 
 PLI_INT32 vpi_release_handle(vpiHandle object) {
@@ -2014,6 +2033,7 @@ PLI_INT32 vpi_release_handle(vpiHandle object) {
     VerilatedVpio* vop = VerilatedVpio::castp(object);
     _VL_VPI_ERROR_RESET();
     if (VL_UNLIKELY(!vop)) return 0;
+
     vpi_remove_cb(object);  // May not be a callback, but that's ok
     VL_DO_DANGLING(delete vop, vop);
     return 1;

test_regress/t/TestVpi.h

@@ -29,7 +29,7 @@ public:
         if (m_handle && m_free) {
             // Below not VL_DO_DANGLING so is portable
             {
-                vpi_free_object(m_handle);
+                vpi_release_handle(m_handle);
                 m_handle = NULL;
             }
         }

test_regress/t/t_vpi_release_dup_bad.out

@@ -0,0 +1,2 @@
+%Error: /svaha/wsnyder/SandBox/homecvs/v4/verilator/test_regress/../include/verilated_vpi.cpp:99: vpi_release_handle() called on same object twice, or on non-Verilator VPI object
+Aborting...

test_regress/t/t_vpi_release_dup_bad.pl

@@ -0,0 +1,25 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+compile(
+    v_flags2 => ["t/$Self->{name}_c.cpp"],
+    verilator_flags2 => ['--vpi'],
+    );
+
+execute(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+
+1;

test_regress/t/t_vpi_release_dup_bad.v

@@ -0,0 +1,15 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under The Creative Commons Public Domain, for
+// any use, without warranty, 2020 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+import "DPI-C" context function void dpii_check();
+
+module t (/*AUTOARG*/);
+   initial begin
+      dpii_check();
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule

test_regress/t/t_vpi_release_dup_bad_c.cpp

@@ -0,0 +1,28 @@
+// -*- mode: C++; c-file-style: "cc-mode" -*-
+//*************************************************************************
+//
+// Copyright 2009-2011 by Wilson Snyder. This program is free software; you
+// can redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License
+// Version 2.0.
+// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+//
+//*************************************************************************
+
+#include <cstdio>
+#include "svdpi.h"
+#include "vpi_user.h"
+//#include "verilated.h"
+
+#include "Vt_vpi_release_dup_bad__Dpi.h"
+
+//======================================================================
+
+void dpii_check() {
+    vpiHandle mod;  // Not TestVpiHandle as testing double free
+    // Verilated::scopesDump();
+    mod = vpi_handle_by_name((PLI_BYTE8*)"top.t", NULL);
+    if (!mod) vpi_printf(const_cast<char*>("-- Cannot vpi_find module\n"));
+    vpi_free_object(mod);  // using vpi_free_object instead of vpi_release_handle for coverage
+    vpi_free_object(mod);  // error: double free
+}