Go Object File Generator

This challenge tasks you with creating a simple Go program that generates a basic object file (.o) from a given Go source file. Object files are a crucial intermediate step in the compilation process, containing machine code and relocation information. Understanding how to generate them (even in a simplified way) provides valuable insight into the Go toolchain and the compilation process.

Problem Description

You are to write a Go program that takes a Go source file path as input and produces a corresponding object file in the same directory. The generated object file should contain a minimal representation of the source code, specifically:

1. Basic Assembly Code: The object file should contain assembly code equivalent to a simple "Hello, World!" program. This doesn't require parsing the input Go file; you'll be hardcoding the assembly.
2. File Header: The object file must start with a valid ELF object file header. For simplicity, you can use a hardcoded header. The header should be suitable for a 32-bit x86 architecture.
3. Section Header: Include a section header describing the code section containing the assembly code.
4. Data Section (Optional): You can optionally include a data section for a string literal "Hello, World!\n".
5. Relocation Table (Optional): For this simplified challenge, relocation information is not required.

The program should handle the following:

• Input Validation: Check if the input file exists. If not, print an error message and exit.
• File Writing: Write the generated object file data to a file with the same name as the input file, but with the ".o" extension.
• Error Handling: Handle potential file writing errors gracefully.

Expected Behavior:

The program should take a Go source file path as a command-line argument. It should then create an object file in the same directory with the same base name but a ".o" extension. The object file should be a valid (though minimal) ELF object file containing assembly code for "Hello, World!".

Examples

Example 1:

Input: main.go
Output: main.o
Explanation: A file named "main.o" is created in the same directory as "main.go". The contents of "main.o" are a valid ELF object file containing assembly code for "Hello, World!".

Example 2:

Input: non_existent_file.go
Output: (Program prints an error message to the console and exits)
Explanation: The input file does not exist, so the program prints an error message and terminates without creating any files.

Constraints

• Architecture: The generated object file should be compatible with a 32-bit x86 architecture.
• ELF Format: The object file must adhere to the basic ELF object file format. You don't need to implement a full ELF parser/generator, but the header and section headers should be valid.
• Assembly Code: The assembly code should be simple enough to fit within a single code section. A "Hello, World!" program is sufficient.
• File Size: The generated object file should be reasonably small (under 1KB).
• Error Handling: The program must handle file I/O errors and invalid input gracefully.
• Input: The input file path is provided as a command-line argument.

Notes

• You will need to research the ELF object file format to understand the structure of the header and section headers. There are many resources available online.
• You can use the syscall package to perform low-level file writing operations.
• This is a simplified challenge. A real object file generator would involve parsing Go source code, generating assembly code, and handling relocation information. This challenge focuses on the basic file format and writing process.
• Consider using a constant for the ELF header to avoid repetition.
• The assembly code can be written directly as a byte array. You don't need to use an assembler.
• Focus on creating a valid object file, even if it's a minimal one. The program doesn't need to be executable.