Code generation issues in compiler design

#CODE GENERATION ISSUES IN COMPILER DESIGN GENERATOR#
#CODE GENERATION ISSUES IN COMPILER DESIGN CODE#
#CODE GENERATION ISSUES IN COMPILER DESIGN PLUS#
#CODE GENERATION ISSUES IN COMPILER DESIGN FREE#

Each identifier can be accessed in symbol table based on width of each identifier and offset.

The identifiers are stored in symbol table during declaration of variables or functions, along with type.

These addresses are based on the runtime environment used like static, stack or heap.

Address mapping defines the mapping between intermediate representations to address in the target code.

#CODE GENERATION ISSUES IN COMPILER DESIGN PLUS#

Index addressing mode- this is of the form C(R) where the address of operand is at the location C+Contents(R)Д®xample: MOV 4(R0), M the operand is located at address = contents (4+contents (R0))Д¬ost of instruction is defined as cost of execution plus the number of memory access. Immediate addressing mode вЂ“ The operand value appears in the instruction.Д.

Register addressing mode where both the operands are in register.Д¬. MOV R0, M moves the contents of register R0 to memory location M.Д«. Target Machine supports for the following addressing modesД®xample: MOV R0, M where M is the address of memory location of one of the operands.

#CODE GENERATION ISSUES IN COMPILER DESIGN CODE#

Producing an assembly language program as output makes the process of code generation somewhat easier. If the target machine does not handle relocation automatically, the compiler must provide explicit relocation information to the loader, to link the separately compiled program segments.

A set of relocatable object modules can be linked together and loaded for execution by a linking loader. Producing a relocatable machine language program as output allows subprograms to be compiled separately. Producing an absolute machine language program as output has the advantage that it can be placed in a fixed location in memory and immediately executed.Re-locatable code provides great deal of flexibilities as the functions can be compiled separately before generation of object code. If it generates assembly level code then assemblers are needed to convert it into machine level code before execution.But in case of re-locatable it requires linker and loader to place the code in appropriate location and map (link) the required library functions.Absolute code can be executed immediately as the addresses are fixed.The target code may be absolute code, re-locatable machine code or assembly language code.The target machine can have either CISC or RISC processor architecture.That language may facilitate some machine-specific instructions to help the compiler generate the code in a more convenient way.

#CODE GENERATION ISSUES IN COMPILER DESIGN GENERATOR#

The code generator has to be aware of the nature of the target language for which the code is to be transformed.

#CODE GENERATION ISSUES IN COMPILER DESIGN FREE#

Assume type checking is done and input in free of errors.

Linear representation like postfix and three address code or quadruples and graphical representation like Syntax tree or DAG.

The main issues in design of code generation are Target code mainly depends on available instruction set and efficient usage of registers.

The output of intermediate code generator may be given directly to code generation or may pass through code optimization before generating code.

Code generator phase generates the target code taking input as intermediate code.

Movement of variables across memory is time consuming and this is the main reason why registers are used as they available within the memory and they are the fastest accessible storage location. Register allocation is the process of assigning program variables to registers and reducing the number of swaps in and out of the registers. Therefore we should try to use minimum number of registers to incur overall low cost. This feature is effectively used by compilers, However registers are not available in large amount and they are costly. Performing various operations on registers is efficient as registers are faster than cache memory.

S - attributed and L - attributed SDTs in Syntax directed translationД¬omputations are generally assumed to be performed on high speed memory locations, known as registers.

Operator grammar and precedence parser in TOC.

Peephole Optimization in Compiler Design.

Syntax Directed Translation in Compiler Design.

Intermediate Code Generation in Compiler Design.

Program to calculate First and Follow sets of given grammar.

Difference between Compiler and Interpreter.

Flex (Fast Lexical Analyzer Generator ).

C program to detect tokens in a C program.

Language Processors: Assembler, Compiler and Interpreter.

Difference between High Level and Low level languages.

ISRO CS Syllabus for Scientist/Engineer Exam.

ISRO CS Original Papers and Official Keys.

GATE CS Original Papers and Official Keys.

Code generation issues in compiler design