Chap 1

Interpretation

-Performing the operations implied by the source program

Compilation

-Translation of a program written in a source language into a semantically equivalent program written in a target language

cross-compiler

A compiler that runs on platform (A) and is capable of generating executable code for platform (B) is called a

Source-to-Source Compiler

A compiler that takes the source code of one programming language and translates it into the source code of another programming language is called a

syntax tree

A parse can be represented by a tree called a parse or

object file

The output of an assembler is called an

Multi pass

compiler may have to keep entire program representation in memory

abstract syntax tree

compilers often use an

object file

contains a combination of machine instructions as well as the data required to place these instructions in memory.

Analysis

determines the operations implied by the source program which are recorded in a tree structure

preprocessor

generally considered as a part of compiler, is a tool that produces input for compilers. It deals with macro-processing, augmentation, file inclusion, language extension, etc.

Linker

is a computer program that links and merges various object files together in order to make an executable file.

Compiler construction

is a microcosm of computer science

Loader

is a part of operating system and is responsible for loading executable files into memory and execute them. It calculates the size of a program (instructions and data) and creates memory space for it. It initializes various registers to initiate execution.

P

is a set of productions — P: N ® (N ÈT)*

Context-free syntax

is specified with a grammar, usually in Backus-Naur form (BNF)

interpreter

reads a statement from the input, converts it to an intermediate code, executes it, then takes the next statement in sequence.

compiler

reads the whole source code at once, creates tokens, checks semantics, generates intermediate code, executes the whole program and may involve many passes.

Synthesis

takes the tree structure and translates the operations therein into the target program

Linker

to search and locate referenced module/routines in a program and to determine the memory location where these codes will be loaded, making the program instruction to have absolute references.

assembler

translates assembly language programs into machine code.

interpreter

translates high-level language into low-level machine language.

Single pass

usually requires everything to be defined before being used in source program

Traditional three-pass compiler

•analyzes and changes IR •goal is to reduce runtime •must preserve values

Optimizer

•constant propagation and folding •code motion •reduction of operator strength •common sub-expression elimination •redundant store elimination •dead code elimination

Register allocation

•have value in a register when used •limited resources •changes instruction choices •can move loads and stores optimal allocation is difficult

Traditional two pass compiler

•intermediate representation (IR) •front end maps legal code into IR •back end maps IR onto target machine •simplify retargeting •allows multiple front ends •multiple passes Þ better code

N

•is a set of non-terminal symbols

T

•is a set of terminal symbols

S

•is the start-symbol

Scanner

•map characters to tokens •character string value for a token is a lexeme •eliminate white space

Instruction selection

•produce compact, fast code •use available addressing modes •pattern matching problem

Parser

•recognize context-free syntax •guide context-sensitive analysis •construct IR(s) •produce meaningful error messages •attempt error correction

Compiler

•recognize legal (and illegal) programs •generate correct code •manage storage of all variables and code •agree on format for object (or assembly) code

Front end

•recognize legal code •report errors •produce IR •preliminary storage map shape code for the back end

Back end

•translate IR into target machine code •choose instructions for each IR operation •decide what to keep in registers at each point •ensure conformance with system interfaces