1. How can a multi-pass compiler can be reduced to a single pass compiler?Explain.
2. In the statement IF<expr> THEN statement ENDIF,explain the syntax,static semantics and execution semantics.
3.Suppose for a moment that c++ did not permit multiple inheritance.In other words,assume that each class can only inherit from one or no other.Describe a scheme for laying out memory at runtime that will enable a compiler to compile such classes.
In your scheme,describe the solutions to the following problems:
1.) Where to put additional data object in a derived class.
2.) How to handle non-virtual functions.
3.) How to handle virtual functions,inclusing problems due to redefinition in derived classes.
4. Generate the three-address codes and quadruples for the following c program segment.Assume that two bytes are required to store each element of the array
sum=0;
p=0;
while(p<=20){
sum=sum+x[p];
p=p+1;
}
5. Explain with an example the simple translation scheme for an assignment statement.
6. In the statement a=b+c*d,explain what is the syntax,the static semantics and execution semantics.
7. Construct a non-deterministic finite automata(NFA) for recognizing the following tokens.
a) a(aa)*
b) (a+b)*a
convert the NFA to an equivalent DFA and make the token recognized by each state of DFA.
8. If a well designed symbol table had a total capacity of around 18,000 and currently contained 10,000 randomly chosen identifiers,approx. how many comparisons would most likely be needed to locate a single identifier inth etable.
9. Construct the parsing table for the following LL(1) grammar
S (arrow sign) aA/B
A (arrow sign) bB/a
B (arrow sign) c/bAc
10.Generate code for the following c program
main()
{
int p;
int x[10];
while(p<=10)
x[p]=0;
}
11. Construct the directed acyclic graph for the following basic block
d=b*c
e=a+b
b=b*c
a=e-d
12. Which phase of the compiling process would be expected to be the first discover an error in the following program and why?
int mail@(){return 0;}
13. Factor loop-invariant expressions in the following loop
while(x>y){
sub=x*Is+d/e;
b[sub]=(a-c)*(x-y);
x--;
}
14.Three advantages and disadvantages of single pass compiler and multi compiler.
