Description

Compilers Laboratory: CS39003
3rd Year CSE: 5th Semester
Assignment – 4: Parser for tinyC Marks: 100
1 Preamble – tinyC
This assignment follows the phase structure grammar specification of C language from the International Standard ISO/IEC 9899:1999 (E). To keep the assignment within our required scope, we have chosen a subset of the specification as given below. We shall refer to this language as tinyC.
The lexical specification of tinyC, also taken and abridged from the Standard, has already been discussed in Assignment 3.
The phase structure grammar specification is written using the common notation of language specifications as discussed in the last assignment.
2 Phrase Structure Grammar of C
1. Expressions
primary-expression: identifier constant string-literal
( expression ) postfix-expression:
primary-expression postfix-expression [ expression ] postfix-expression ( argument-expression-listopt ) postfix-expression . identifier postfix-expression − > identifier postfix-expression ++ postfix-expression −− ( type-name ) { initializer-list }
( type-name ) { initializer-list , } argument-expression-list:
assignment-expression
argument-expression-list , assignment-expression
unary-expression:
postfix-expression ++ unary-expression −− unary-expression unary-operator cast-expression sizeof unary-expression sizeof ( type-name )
unary-operator: one of
& * + – ~ !
cast-expression:
unary-expression
( type-name ) cast-expression multiplicative-expression:
cast-expression multiplicative-expression ∗ cast-expression multiplicative-expression / cast-expression multiplicative-expression % cast-expression additive-expression:
multiplicative-expression additive-expression + multiplicative-expression additive-expression − multiplicative-expression
shift-expression:
additive-expression shift-expression << additive-expression shift-expression >> additive-expression
relational-expression:
shift-expression relational-expression < shift-expression relational-expression > shift-expression relational-expression <= shift-expression relational-expression >= shift-expression
equality-expression:
relational-expression equality-expression == relational-expression equality-expression ! = relational-expression AND-expression:
equality-expression
AND-expression & equality-expression exclusive-OR-expression: AND-expression exclusive-OR-expressionˆAND-expression
inclusive-OR-expression:
exclusive-OR-expression inclusive-OR-expression | exclusive-OR-expression
logical-AND-expression:
inclusive-OR-expression logical-AND-expression && inclusive-OR-expression
logical-OR-expression:
logical-AND-expression logical-OR-expression || logical-AND-expression
conditional-expression:
logical-OR-expression logical-OR-expression ? expression : conditional-expression
assignment-expression:
conditional-expression unary-expression assignment-operator assignment-expression
assignment-operator: one of
= *= /= %= += -= <<= >>= &= ^= |=
expression:
assignment-expression expression , assignment-expression
constant-expression: conditional-expression
2. Declarations declaration:
declaration-specifiers init-declarator-listopt ;
declaration-specifiers:
storage-class-specifier declaration-specifiersopt type-specifier declaration-specifiersopt type-qualifier declaration-specifiersopt function-specifier declaration-specifiersopt
init-declarator-list:
init-declarator init-declarator-list , init-declarator
init-declarator:
declarator declarator = initializer storage-class-specifier: extern static auto register type-specifier: void char short int long float double signed unsigned
Bool
Complex
Imaginary
enum-specifier specifier-qualifier-list:
type-specifier specifier-qualifier-listopt type-qualifier specifier-qualifier-listopt
enum-specifier:
enum identifieropt { enumerator-list } enum identifieropt { enumerator-list , } enum identifier
enumerator-list:
enumerator enumerator-list , enumerator
enumerator:
enumeration-constant enumeration-constant = constant-expression type-qualifier: const restrict volatile
function-specifier: inline
declarator: pointeropt direct-declarator
direct-declarator: identifier
( declarator ) direct-declarator [ type-qualifier-listopt assignment-expressionopt ] direct-declarator
[ static type-qualifier-listopt assignment-expression ] direct-declarator [ type-qualifier-list static assignment-expression ] direct-declarator [ type-qualifier-listopt * ] direct-declarator ( parameter-type-list ) direct-declarator ( identifier-listopt )
pointer:
* type-qualifier-listopt
* type-qualifier-listopt pointer type-qualifier-list:
type-qualifier type-qualifier-list type-qualifier
parameter-type-list: parameter-list parameter-list , … parameter-list:
parameter-declaration parameter-list , parameter-declaration parameter-declaration: declaration-specifiers declarator declaration-specifiers
identifier-list:
identifier identifier-list , identifier
type-name:
specifier-qualifier-list
initializer:
assignment-expression { initializer-list }
{ initializer-list , } initializer-list:
designationopt initializer initializer-list , designationopt initializer
designation: designator-list =
designator-list:
designator designator-list designator
designator:
[ constant-expression ]
. identifier
3. Statements statement:
labeled-statement compound-statement expression-statement selection-statement iteration-statement jump-statement
labeled-statement:
identifier : statement case constant-expression : statement default : statement
compound-statement:
{ block-item-listopt } block-item-list:
block-item block-item-list block-item
block-item: declaration statement
expression-statement: expressionopt ;
selection-statement:
if ( expression ) statement if ( expression ) statement else statement switch ( expression ) statement iteration-statement:
while ( expression ) statement do statement while ( expression ) ; for ( expressionopt ; expressionopt ; expressionopt ) statement for ( declaration expressionopt ; expressionopt ) statement
jump-statement: goto identifier ; continue ; break ; return expressionopt ;
4. External definitions translation-unit:
external-declaration translation-unit external-declaration
external-declaration: function-definition declaration
function-definition: declaration-specifiers declarator declaration-listopt compound-statement
declaration-list:
declaration declaration-list declaration
3 The Assignment
1. Write a bison specification for defining the tokens of tinyC and generate the required y.tab.h file.
argument-expression-listopt
are shown as optional on the right-hand-side as: postfix-expression:
postfix-expression ( argument-expression-listopt )
One way to handle them would be to introduce a new non-terminal, argument-expression-list-opt, and a pair of new productions:
argument-expression-list-opt:
argument-expression-list
and change the above rule as: postfix-expression:
postfix-expression ( argument-expression-list-opt )
4. Names of your .l and .y files should be asgn4 roll.l and asgn4 roll.y respectively. The .y or the .l file should not contain the function main(). Write your main() (in a separate file asgn4 roll.c) to test your lexer and parser.
5. Prepare a Makefile to compile the specifications and generate the lexer and the parser.
6. Prepare a test input file asgn4 roll test.c that will test all the rules that you have coded.
7. Prepare a tar-archive with the name asgn4 roll.tar containing all the files and upload to Moodle.
4 Credits
1. Specifications and testing: 70
2. Main file and makefile: 10
3. Test file: 20