Fix $c() inside a DPI export (#8402). [Nazar Zibilyuk]

Fixes #8402.

Changes

@@ -106,6 +106,7 @@ Verilator 5.053 devel
 * Fix error on non-existent interface ports (#8393). [Andrii Andrieiev, Antmicro Ltd.]
 * Fix compile-time blowup forcing large unpacked arrays (#8395). [Jonathan Drolet]
 * Fix false MULTIDRIVEN for writes in tasks never executed (#8401). [Artur Bieniek, Antmicro Ltd.]
+* Fix $c() inside a DPI export (#8402). [Nazar Zibilyuk]
 * Fix covergroup constructor initialization (#8410). [Marco Bartoli]
 * Fix issues with configuring flex during build on MacOS (#8412). [Kaleb Barrett]
 * Fix interface modport resolution against non-scope symbol tables (#8420). [Geza Lore, Testorrent USA, Inc.]

src/V3Depth.cpp

@@ -110,7 +110,10 @@ class DepthVisitor final : public VNVisitor {
     // (Here instead of new visitor after V3Descope just to avoid another visitor)
     void needNonStaticFunc(AstNode* nodep) {
         UASSERT_OBJ(m_cfuncp, nodep, "Non-static accessor not under a function");
-        if (m_cfuncp->isStatic()) {
+        // DPI export implementations are always invoked via the generic DPI dispatcher,
+        // which can only ever supply the symbol table pointer, never a scope-specific
+        // "this", so they must remain static regardless of what they contain.
+        if (m_cfuncp->isStatic() && !m_cfuncp->dpiExportImpl()) {
             UINFO(5, "Mark non-public due to " << nodep);
             m_cfuncp->isStatic(false);
         }

src/V3EmitCModel.cpp

@@ -31,8 +31,6 @@ class EmitCModel final : public EmitCFunc {
     using CFuncVector = std::vector<const AstCFunc*>;
 
     // MEMBERS
-    // Needed to emit references to functions of the model, e.g. entry points
-    const EmitCParentModule m_emitCParentModule;
     V3UniqueNames m_uniqueNames;  // For generating unique file names
 
     // METHODS

src/Verilator.cpp

@@ -48,6 +48,7 @@
 #include "V3DfgOptimizer.h"
 #include "V3DiagSarif.h"
 #include "V3EmitC.h"
+#include "V3EmitCBase.h"
 #include "V3EmitCMain.h"
 #include "V3EmitMk.h"
 #include "V3EmitMkJson.h"
@@ -628,6 +629,8 @@ static void process() {
         // Output the text
         if (!v3Global.opt.lintOnly() && !v3Global.opt.serializeOnly()
             && !v3Global.opt.dpiHdrOnly()) {
+            // Make parent module pointers available for all Emit stages below
+            const EmitCParentModule emitCParentModule;
             // emitcInlines is first, as it may set needHInlines which other emitters read
             V3EmitC::emitcInlines();
             V3EmitC::emitcSyms();

test_regress/t/t_dpi_export.v

@@ -23,7 +23,12 @@ module t;
   import "DPI-C" context function int dpix_run_tests();
 
   export "DPI-C" task dpix_t_int;
-  task dpix_t_int(input int i, output int o);  o = ~i; endtask
+  task dpix_t_int(input int i, output int o);
+`ifdef VERILATOR
+    $c(";");  // Test issue #8402
+`endif
+    o = ~i;
+  endtask
 
   export "DPI-C" dpix_t_renamed = task dpix_t_ren;
   task dpix_t_ren(input int i, output int o);  o = i+2; endtask