Description
Objective: To design and implement a mini compiler consisting lexer, parser, and semantic analyzer, to deal with variable declarations in a block structured language.
As learned in class, semantic analysis/translation can be peformed while parsing itself by implementing the rules/actions with the parser. The task for this lab is the following. Consider type declarations in a block structured language like C, in which a program may be written in terms blocks where each block may have declaration section followed by the statements section. Consider variable declarations consisting of premitive data types int, float , char, composite data type, array (including multidimensional arrays), and pointers. Assume sizes of char, float, and int data types are 1, 4, and 4 bytes respectively. Also consider the size of a pointer variable as 4 bytes.
Design a grammar to generate the all possible type declarations consisting of data types mentioned above, and implement the necessary functionality
-
to add the type information for each identifier defined in the program,
-
to find the size requirements for each declaration section,
-
to maintain the relative memory address (i.e., offset) for each variable declared. Assume 16-bit memory addresses.
Note that in next lab session, you require use these type declarations for typechecking and intermediate code generation.
Input : Blocks of C variable declarations
Output: Display symbol table entries
Execusion: $./minicc prog.c
1. Testcase:
Input:
{
i n t a , b , c ;
-
char
e ;
f l o a t p i = 3 . 2 4 ;
}
Output:
0 x0 0 0 0
a
i n t
0 x0 0 0 4
b
i n t
0 x0 0 0 8
c
i n t
0 x0 0 0 9
e
char
0 x000A
p i
f l o a t 3 . 2 4
2. Testcase:
Input:
-
{
i n t a ;
i n t x ,
y ;
f l o a t
c ;
{
i n t a ;
i n t b ;
}
{
char m;
i n t n [ 1 0 ] ;
}
}
Output:
0 x0 0 0 0
a
i n t
0 x0 0 0 4
x
i n t
0 x0 0 0 8
y
i n t
0 x000C
c f l o a t
0 x0 0 0 0
a
i n t
0 x0 0 0 4
b
i n t
0 x0 0 0 0
m char
0 x0 0 0 1
n i n t a r r a y 40
3. Testcase
Input:
{
i n t a ;
i n t b ;
i n t a ;
}
Output:
e r r o r : r e d e c l a r a t i o n o f ’ a ’
4. Testcase
Input:
{
i n t a ;
char a ;
{
i n t c ;
i n t c ;
}
}
Output:
e r r o r : c o n f l i c t i n g t y p e s f o r ’ a ’
e r r o r : r e d e c l a r a t i o n o f ’ c ’
