Lots of basic questions are there in my mind. I need to clear them.
Statement 1: A compiler converts a human-readable codes to object codes, and those are converted to a machine code (executable) by linker.
Am I right here?
At wikipedia, it is written that
Object files are produced by an assembler, compiler, or other language
translator, and used as input to the linker.
Question 1: An assembler converts assembly language code (MOV A, B ADD C) to machine code. In case of high-level language like C++, that is generated by linker above. So assembler is not used anywhere. So how can it create an object file as written above?
Intermediate code is generated to make the code run on different architectures.
Question 2: Are *.class (bytecode) files created by java compiler object files? If yes, then can we say that the JVM that runs them is a type of linker (however its not creating the executable)?
Question 3: When we compile a C++ program in Turbo C++, we get *.obj files which are the object files. Can we use them to generate the executable in some other architecture?
Question 1: yes, an assembler (as, gas, nasm, masm) compiles assembly instructions to object code. In case of high-level languages (H) the compiler compiles H to either another language (for example GHC, the Glorious Haskell Compiler can produce C, but it can also produce C--, and there was an attempt(?) to produce Java), or into object code through intermediate steps (or languages C-- or Core).
Intermediate code can be generated for many reasons: 1. portability for example .class files from java, p-code for Pascal 2. to facilitate code optimisations
Question 2: .class files can be generated by a java compiler, but Scala also generates .class files, and AspectJ (the aspect oriented flavour) also produces .class files. .class files are not object files in the sense that they need the Java Virtual Machine (and the unix linker ld won't link .class files against .o files). The original JVM is an interpreter for .class files, but you can compile java on-the-fly too.
Question 3: Turbo C++ .obj files (compiled on 64 bit intel) would not be happy on a Z80 machine unless the compiler has the option of cross-compiling for another architecture, so in the case of Turbo C++ the purpose of the object file is not portability across platforms.