Posts by SirCrus

Dear Embedded Enthusiasts,

we have trouble with J-Scope since newly introducing the C++20 data type std::strong_ordering into our code base.
After selecting the ELF file and starting to load, J-Scope (in all recent versions) will parse the file until a certain point and then stop, resulting in crashes after a minute or so in both Linux and Windows versions of J-Scope (Bluescreen on Windows, unresponsive UI on Linux with subsequent crash).

I have trouble reproducing this with a small complete example as it does not seem to crash on a very small ELF file, otherwise I would supply one here.
This is the offending code:

class MyClass
{
public:
    MyClass() = default;
private:
    std::strong_ordering something{std::strong_ordering::equal};


};

Does anyone else experience such issues?

We have encountered a crash scenario with J-Scope V7.92f (version 7.70e is the last one that does not crash) during parsing of an ELF-file that contains a C++ class with more than one factory method (using arm-none-eabi-g++-12)

Example code to reproduce:

#define MAKE_ME_FAIL


class MyClass
{
public:
    MyClass() = default;


    MyClass(int i) : rawVal(i){};


    static MyClass Method(int i)
    {
        return MyClass(i);
    };
#ifdef MAKE_ME_FAIL
    static MyClass AnotherMethod(int i)
    {
        return MyClass(i);
    };
#endif
    int rawVal;
};


MyClass fixp;


int main(void){
    return 0;
}

Trying to load with MAKE_ME_FAIL defined will make max out the CPU usage of J-Scope, until it finally crashes. The screen freezes with this window:

When only using one factory method (MAKE_ME_FAIL is false), the program does not crash, but there are already hints why it goes wrong: there seems to be a recursion when parsing the symbols:

Please provide a fix so our teams can continue using this useful tool with our c++-codebase.

You can use arm-none-eabi-g++ -gdwarf-4 -T linker.ld main.cpp -o main.elf to reproduce, with this minimum linker file:

MEMORY
{
    FLASH (rx) : ORIGIN = 0x08000000, LENGTH = 64K
    RAM (rw)  : ORIGIN = 0x20000000, LENGTH = 20K
}


ENTRY(main)


SECTIONS
{
    .text : {
        KEEP(*(.vector_table))
        *(.text)
        *(.text*)
        __data_source = .;
        . = ALIGN(4);
    } > FLASH


    .data : {
        __data_start = .;
        *(.data)
        . = ALIGN(4);
        __data_size = SIZEOF(.data);
    } > RAM AT> FLASH


    .bss : {
        __bss_start = .;
        *(.bss)
        *(.bss*)
        . = ALIGN(4);
        __bss_size = SIZEOF(.bss);
    } > RAM


    .stack (NOLOAD) : {
        . = . + 0x400;  /* Stack size */
        __stack = .;
    } > RAM
}