Add traceCapable indication to model header (#5053).

Changes

@@ -19,6 +19,7 @@ Verilator 5.025 devel
 * Add CITATION.cff (#5057) (#5058). [Gijs Burghoorn]
 * Add VPI eval needed tracking (#5065). [Todd Strader]
 * Add `--localize-max-size` option and optimization (#5072).
+* Add traceCapable indication to model header (#5053). [Vito Gamberini]
 * Fix missing flex include path variable (#4970) (#4971). [Christopher Taylor]
 * Fix missing parameters with comma to be errors (#4979) (#5012). [Paul Swirhun]
 * Fix bound queue printing (#5032). [Aleksander Kiryk, Antmicro Ltd.]

src/V3EmitCModel.cpp

@@ -101,6 +101,12 @@ class EmitCModel final : public EmitCFunc {
 
         puts("\n");
         ofp()->putsPrivate(false);  // public:
+
+        puts("\n// CONSTEXPR CAPABILITIES\n");
+        puts("// Verilated with --trace?\n");
+        puts("static constexpr bool traceCapable = "s
+             + (v3Global.opt.trace() ? "true;\n"s : "false;\n"s));
+
         // User accessible IO
         puts("\n// PORTS\n"
              "// The application code writes and reads these signals to\n"

test_regress/t/t_trace_cat.cpp

@@ -13,6 +13,10 @@
 
 #include VM_PREFIX_INCLUDE
 
+#include "TestCheck.h"
+
+int errors = 0;
+
 unsigned long long main_time = 0;
 double sc_time_stamp() { return (double)main_time; }
 
@@ -32,6 +36,9 @@ int main(int argc, char** argv) {
     std::unique_ptr<VerilatedVcdC> tfp{new VerilatedVcdC};
     top->trace(tfp.get(), 99);
 
+    // Test for traceCapable - randomly-ish selected this test
+    TEST_CHECK_EQ(top->traceCapable, true);
+
     tfp->open(trace_name());
 
     top->clk = 0;
@@ -63,5 +70,5 @@ int main(int argc, char** argv) {
     tfp.reset();
     top.reset();
     printf("*-* All Finished *-*\n");
-    return 0;
+    return errors;
 }