How to find begin/end sigautre from ASTVisitor

[HungMingWu]

Hi, Mike
I met an issue.
Here is the test case

class C;
        int a;
        task T();
                int arr[5];
                blk_1: foreach(arr[j]) begin
                        $display("1");
                        blk_2: for (int of = 0; of < 5; of++) begin : blk_3
                            int c;
                            blk_4 : foreach(arr[k]) begin
                                int d;
                            end
                        end
                end
        endtask
endclass

module top;
    C c;
    int blk_1;
    initial begin
        c.T();
    end
endmodule

I think BlockStatement is what I needed, but I cannot judge whether it have begin/end signature.
Am I missing something?

[MikePopoloski]

I'm not sure what you're asking. What is a begin/end signature? Do you mean the block name? The BlockStatement points to the BlockSymbol which has a name.

[HungMingWu]

From my view, there are three begin-end signature from this case.

foreach(arr[j]) begin
end

foreach(arr[k]) begin
end

and

initial begin
end

I find some resource from stackoverflow
It says

If a function contains more than one statement, the statements must be enclosed in a begin-end or fork-join block.
But it doesn't satisfy the last case.

[MikePopoloski]

Well like I said you can look for BlockStatements which represent the sequential blocks implied by begin/end pairs. For that last case you posted the BlockStatement will be the body of the ProceduralBlockSymbol which represents the initial block.

[HungMingWu]

Here is my experimental code

    void visit(const BlockStatement& stmt) {
        std::cout << "BlockStatement: " << &stmt << ", kind: " << toString(stmt.blockKind) << "\n";
        if (stmt.blockSymbol) {
            std::cout << stmt.blockSymbol << ", name: " << stmt.blockSymbol->name
                      << ", kind: " << toString(stmt.blockSymbol->kind)
                      << "\n";
        }
        else {
            std::cout << "blockSymbol is nullptr\n";
        }
       stmt.body.visit(*this);
    }

The output is

Before BlockStatement: 000001C6C65DDC70, kind: Sequential
000001C6C65D9580, name: blk_1, kind: StatementBlock
Before BlockStatement: 000001C6C65DDBA0, kind: Sequential
blockSymbol is nullptr
Before BlockStatement: 000001C6C65DDAE8, kind: Sequential
000001C6C65D9620, name: blk_2, kind: StatementBlock
Before BlockStatement: 000001C6C65DD9A0, kind: Sequential
000001C6C65D9778, name: blk_3, kind: StatementBlock
Before BlockStatement: 000001C6C65DD8E8, kind: Sequential
000001C6C65D98D0, name: blk_4, kind: StatementBlock
Before BlockStatement: 000001C6C65DD818, kind: Sequential
000001C6C65D9970, name: , kind: StatementBlock
Before BlockStatement: 000001C6C65DE0F8, kind: Sequential
blockSymbol is nullptr

There are 7 BlockStatements, and all are Sequential.
I think a better way is append an attribute on BlockStatement
How do you think?

[MikePopoloski]

Yes, some implicit blocks (unnamed) are created by the loops. What would you like this additional attribute to indicate? Also if it helps you can access the syntax node for each statement and see if it corresponds to a literal begin/end as written by the user.