Fix compilation error on unreachable disable fork / wait fork (verila…

…tor#5339) Signed-off-by: Arkadiusz Kozdra <[email protected]>
antmicro · Aug 7, 2024 · f78c4e8 · f78c4e8
1 parent e6fe367
commit f78c4e8
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Showing 2 changed files with 25 additions and 14 deletions.
diff --git a/src/V3Timing.cpp b/src/V3Timing.cpp
@@ -341,17 +341,12 @@ class TimingSuspendableVisitor final : public VNVisitor {
         }
     }
     void visit(AstNodeCCall* nodep) override {
-        if (!m_underFork || (m_underFork & F_MIGHT_SUSPEND))
-            new V3GraphEdge{&m_suspGraph, getSuspendDepVtx(nodep->funcp()),
-                            getSuspendDepVtx(m_procp), m_underFork ? P_FORK : P_CALL};
+        new V3GraphEdge{&m_suspGraph, getSuspendDepVtx(nodep->funcp()), getSuspendDepVtx(m_procp),
+                        P_CALL};
 
         new V3GraphEdge{&m_procGraph, getNeedsProcDepVtx(nodep->funcp()),
                         getNeedsProcDepVtx(m_procp), P_CALL};
 
-        if (m_underFork && !(m_underFork & F_MIGHT_SUSPEND)) {
-            addFlags(nodep, T_NEEDS_PROC | T_ALLOCS_PROC);
-        }
-
         iterateChildren(nodep);
     }
     void visit(AstBegin* nodep) override {
@@ -365,9 +360,7 @@ class TimingSuspendableVisitor final : public VNVisitor {
         new V3GraphEdge{&m_procGraph, getNeedsProcDepVtx(nodep), getNeedsProcDepVtx(m_procp),
                         P_CALL};
 
-        if (m_underFork && !(m_underFork & F_MIGHT_SUSPEND)) {
-            addFlags(nodep, T_NEEDS_PROC | T_ALLOCS_PROC);
-        }
+        if (m_underFork) addFlags(nodep, T_NEEDS_PROC | T_ALLOCS_PROC);
 
         m_procp = nodep;
         m_underFork = 0;
@@ -1128,11 +1121,22 @@ class TimingControlVisitor final : public VNVisitor {
         // var
         alwaysp->addNextHere(nodep);
     }
+    void visit(AstDisableFork* nodep) override {
+        if (hasFlags(m_procp, T_HAS_PROC)) return;
+        // never reached by any process; remove to avoid compilation error
+        VL_DO_DANGLING(nodep->unlinkFrBack()->deleteTree(), nodep);
+    }
     void visit(AstWaitFork* nodep) override {
-        AstCExpr* const exprp = new AstCExpr{nodep->fileline(), "vlProcess->completedFork()", 1};
-        exprp->pure(false);
-        AstWait* const waitp = new AstWait{nodep->fileline(), exprp, nullptr};
-        nodep->replaceWith(waitp);
+        if (hasFlags(m_procp, T_HAS_PROC)) {
+            AstCExpr* const exprp
+                = new AstCExpr{nodep->fileline(), "vlProcess->completedFork()", 1};
+            exprp->pure(false);
+            AstWait* const waitp = new AstWait{nodep->fileline(), exprp, nullptr};
+            nodep->replaceWith(waitp);
+        } else {
+            // never reached by any process; remove to avoid compilation error
+            nodep->unlinkFrBack();
+        }
         VL_DO_DANGLING(nodep->deleteTree(), nodep);
     }
     void visit(AstWait* nodep) override {

diff --git a/test_regress/t/t_disable_fork3.v b/test_regress/t/t_disable_fork3.v
@@ -4,6 +4,13 @@
 // any use, without warranty, 2023 by Antmicro Ltd.
 // SPDX-License-Identifier: CC0-1.0
 
+class C;
+   task proc;
+      disable fork;
+      wait fork;
+   endtask
+endclass
+
 module t;
    initial begin
       fork begin