ExportToHeaderAction: pointer to array has incorrect type

[mattiasgrenfeldt]

Describe the bug When I export my types to a C header file using the ExportToHeaderAction, fields in structs that are pointers to arrays will get an incorrect declaration in the header file.

To Reproduce Steps to reproduce the behavior:

1. Make a struct having one field with the type int[12]*. Like so:
2. Export the type to a C header by right clicking the type in the Data Type Manager and clicking "Export C Header...".
3. The result will look like this:

typedef unsigned char   undefined;

typedef unsigned char    byte;
typedef unsigned char    dwfenc;
typedef unsigned int    dword;
typedef unsigned long    qword;
typedef unsigned int    undefined4;
typedef unsigned long    undefined8;
typedef unsigned short    word;
typedef struct structA structA, *PstructA;

struct structA {
    int[12] * something;
};

When I try to compile it using gcc, it's not happy about the something field.

Expected behavior From what I've found online, structA should instead look like this:

struct structA {
    int (*something)[12];
};

Environment:

• Ghidra Version: 10.2.3

[mattiasgrenfeldt]

Similarly to my other issue #5240 , the decompiler view and export seems to handle this well:

[mattiasgrenfeldt]

My current workaround is to make a copy of Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/data/DataTypeWriter.java and change getTypeDeclaration:

private String getTypeDeclaration(/* ... */){
    // ...
    if (componentString == null) {
        if (dataType instanceof BitFieldDataType) {
            BitFieldDataType bfDt = (BitFieldDataType) dataType;
            name += ":" + bfDt.getDeclaredBitSize();
            dataType = bfDt.getBaseDataType();
        } else if (dataType instanceof Array) {
            Array array = (Array) dataType;
            name += getArrayDimensions(array);
            dataType = getArrayBaseType(array);
        } else if (dataType instanceof Pointer pointer) { // <-- Added this else if and its body
            DataType element = getPointerBaseDataType(pointer);
            if (element != null) {
                name = "*" + name;
                dataType = element;
                if (dataType instanceof Array array) {
                    name = "(" + name + ")" + getArrayDimensions(array);
                    dataType = getArrayBaseType(array);
                }
            }
        }
        // ...
    }
    // ...
}

EDIT: This "workaround" was incorrect, I rewrote the code to something else that worked later.

[ryanmkurtz]

EDIT: This "workaround" was incorrect, I rewrote the code to something else that worked later.

@mattiasgrenfeldt Apologies for taking so long to get to this, but I'm preparing to address it. I'm curious if you'd like to share your final solution.

[ryanmkurtz]

I assume you added some support for pointers to pointers to pointers, for example:

struct structA {
    int (*****something)[12];
};

[mattiasgrenfeldt]

Hello Ryan! Sorry for not answering earlier, but here is what I changed in getTypeDeclaration:

        if (componentString == null) {
            if (dataType instanceof BitFieldDataType) {
                BitFieldDataType bfDt = (BitFieldDataType) dataType;
                name += ":" + bfDt.getDeclaredBitSize();
                dataType = bfDt.getBaseDataType();
            }
            // Remove the else ifs and add a while
            while (true) {
                if (dataType instanceof Array array) {
                    name += "[" + array.getNumElements() + "]";
                    dataType = array.getDataType();
                } else if (dataType instanceof Pointer pointer) {
                    DataType elem = pointer.getDataType();
                    if (elem == null) {
                        break;
                    }
                    name = "*" + name;
                    dataType = elem;
                    if (dataType instanceof Array) {
                        name = "(" + name + ")";
                    }
                } else {
                    break;
                }
            }
            // End of modification

            DataType baseDataType = getBaseDataType(dataType);
            if (baseDataType instanceof FunctionDefinition) {
                componentString = getFunctionPointerString((FunctionDefinition) baseDataType, name,
                        dataType, writeEnabled, monitor);
            } else {
                componentString = getDataTypePrefix(dataType) + cleanIdentifier(dataType.getDisplayName());
                if (name.length() != 0) {
                    componentString += " " + name;
                }
            }
            sb.append(componentString);
        }

Because it might not just be pointers in series, there might be any combination of pointer to array of pointers to arrays, etc. Example

struct structA {
    int (*(*****something)[12])[2][3];
};

[ryanmkurtz]

@mattiasgrenfeldt, thanks, i've tested this and will go with your final implementation.