Verilator

There is memory corruption when modules are instantiated with a triangle pattern. The error only occurs if C is instantiated before B. Disabling the destructor of VSymGraph resolves the issue, but of course introduces a memory leak. It isn't obvious to me where the correct fix would go.

Fails against 3.840 and master branch. Passes on 3.833.

A
|\
| B
|/
C

// A.v
module A;
    C c();
    B b();
endmodule

// B.v
module B;
    C c();
endmodule

// C.v
module C;
    initial
        $display( "Hello World" );
endmodule

> valgrind verilator_bin --lint-only A.v

==2854== Invalid read of size 8
==2854==    at 0x40667D: VSymEnt::nodep() const (V3SymTable.h:96)
==2854==    by 0x44EA27: V3ParseImp::lexToken() (verilog.l:1130)
==2854==    by 0x44EB5B: V3ParseImp::lexToBison() (verilog.l:1150)
==2854==    by 0x40EBF3: yyparse() (verilog.c:7757)
==2854==    by 0x429D18: V3ParseImp::bisonParse() (verilog.y:3283)
==2854==    by 0x404BE6: V3ParseImp::lexFile(std::string const&) (V3ParseImp.cpp:156)
==2854==    by 0x40539E: V3ParseImp::parseFile(FileLine*, std::string const&, bool, std::string const&) (V3ParseImp.cpp:143)
==2854==    by 0x405417: V3Parse::parseFile(FileLine*, std::string const&, bool, std::string const&) (V3ParseImp.cpp:170)
==2854==    by 0x5905F8: LinkCellsVisitor::visit(AstCell*, AstNUser*) (V3LinkCells.cpp:206)
==2854==    by 0x4974AB: AstCell::accept(AstNVisitor&, AstNUser*) (V3AstNodes.h:1283)
==2854==    by 0x48ECB4: AstNode::iterateAndNext(AstNVisitor&, AstNUser*) (V3Ast.cpp:768)
==2854==    by 0x48EE0E: AstNode::iterateChildren(AstNVisitor&, AstNUser*) (V3Ast.cpp:748)
==2854==  Address 0x5982300 is 48 bytes inside a block of size 88 free'd
==2854==    at 0x4C26DCF: operator delete(void*) (vg_replace_malloc.c:387)
==2854==    by 0x40A43C: VSymGraph::~VSymGraph() (V3SymTable.h:221)
==2854==    by 0x40A4D1: V3ParseSym::~V3ParseSym() (V3ParseImp.h:200)
==2854==    by 0x405A12: V3ParseImp::~V3ParseImp() (V3ParseImp.cpp:67)
==2854==    by 0x405B12: V3Parse::~V3Parse() (V3ParseImp.cpp:166)
==2854==    by 0x5907B9: LinkCellsVisitor::visit(AstCell*, AstNUser*) (V3LinkCells.cpp:214)
==2854==    by 0x4974AB: AstCell::accept(AstNVisitor&, AstNUser*) (V3AstNodes.h:1283)
==2854==    by 0x48ECB4: AstNode::iterateAndNext(AstNVisitor&, AstNUser*) (V3Ast.cpp:768)
==2854==    by 0x48EE0E: AstNode::iterateChildren(AstNVisitor&, AstNUser*) (V3Ast.cpp:748)
==2854==    by 0x58FA5E: LinkCellsVisitor::visit(AstNodeModule*, AstNUser*) (V3LinkCells.cpp:182)
==2854==    by 0x47D189: AstNVisitor::visit(AstModule*, AstNUser*) (V3Ast__gen_visitor.h:119)
==2854==    by 0x42BDD9: AstModule::accept(AstNVisitor&, AstNUser*) (V3AstNodes.h:1222)