Study Notes on Intermediate Code Generation

• The designer of the compiler decides the intermediate language.
• Syntax trees can be used as an intermediate language.
• Postfix notations, three address codes (quadruples) can be used as an intermediate language.

Syntax Tree

Syntax tree is a variant of the parse tree, where each leaf represents an operand and each interior node represent an operator.

A sentence a * (b +d) would have the following syntax tree

Three-Address Code

When each statement contains three addresses (two for operands and one for result), Most general kind of three-address code is

x = yop z

Where x, y and z are names, constants or compiler generated temporaries and op is any operator.

But we can also use the following notation for quadruples (much better notation because it looks like a machine code instruction)

Op y, z, x

Apply operator op to y and z and store the result in x.

Representation of Three-Address Codes

Three-address code can be represented in various forms i.e., quadruples, triples and indirect triples. These forms are demonstrated by way of examples below.

e.g., A = – B*(C +0)

Three address code is as follow

T1 = – B

T2 = C + D

T3 = T1* T2

A = T3

Quadruples

Triples

Indirect triple

You can follow the detailed champion study plan for GATE CS 2022 from the following link:

Detailed GATE CSE 2022 Champion Study Plan

Candidates can also practice 110+ Mock tests for exams like GATE, NIELIT with BYJU’S Exam Prep Test Series check the following link:

Click Here to Avail GATE CSE Test Series!(100+ Mock Tests)

Get unlimited access to 21+ structured Live Courses all 112+ mock tests with Online Classroom Program for GATE CS & PSU Exams:

Click here to avail Online Classroom Program for Computer Science Engineering

Thanks.