Codegen: FB invocation does not generate input assignments

[Jan-Bulthuis]

Problem

When an instance of a function block is stored in a VAR_GLOBAL, invoking it seems to have the incorrect codegen. As a result, the final C++ file does not compile.

Impact

• STruCpp states that compilation is succesfull
• The resulting C++ file can not be compiled

Reproduction

Consider this minimal example:

FUNCTION_BLOCK FB_AND
    VAR_INPUT
        I1 : BOOL;
        I2 : BOOL;
    END_VAR
    VAR_OUTPUT
        Q1 : BOOL;
    END_VAR

    Q1 := I1 AND I2;
END_FUNCTION_BLOCK

VAR_GLOBAL
    FB_AND_INST : FB_AND;
END_VAR

FUNCTION FUN : BOOL
    FB_AND_INST(I1 := TRUE, I2 := FALSE);
    FUN := FB_AND_INST.Q1;
END_FUNCTION

STruCpp converts this to the following C++:

// Generated by STruC++ - IEC 61131-3 Structured Text to C++ Compiler
// Do not edit this file manually.

#include "code.hpp"

namespace strucpp {

}  // namespace strucpp
// Generated by STruC++ - IEC 61131-3 Structured Text to C++ Compiler
// Do not edit this file manually.

#include "code.hpp"

namespace strucpp {

FB_AND::FB_AND() {
    // Initialize variables
}

void FB_AND::operator()() {
    Q1 = (I1) & (I2);
}

}  // namespace strucpp
// Generated by STruC++ - IEC 61131-3 Structured Text to C++ Compiler
// Do not edit this file manually.

#include "code.hpp"

namespace strucpp {

IEC_BOOL FUN() {
    IEC_BOOL FUN_result;
    FB_AND_INST(true, false);
    FUN_result = FB_AND_INST.Q1;
    return FUN_result;
}

}  // namespace strucpp

The line FB_AND_INST(true, false) does not compile. Based on tests/backend/codegen-fb.test.ts, specifically test FB invocation codegen I would expect the code to look like

FB_AND_INST.I1 = true;
FB_AND_INST.I2 = false;
FB_AND_INST();

Code Locations

No response

Fix

No response

Acceptance

The explicit assignment statements are generated and the generated code compiles :)