List of top Compiler Design Questions

Given the following syntax directed translation rules: 
Rule 1: \( R \to AB \) { \( B.i = R.i - 1 \); \( A.i = B.i \); \( R.i = A.i + 1 \); } 
Rule 2: \( P \to CD \) { \( P.i = C.i + D.i \); \( D.i = C.i + 2 \); } 
Rule 3: \( Q \to EF \) { \( Q.i = E.i + F.i \); } 
Which ONE is the CORRECT option among the following?

Consider the following statements about the use of backpatching in a compiler for intermediate code generation: 
1. Backpatching can be used to generate code for Boolean expressions in one pass. 
2. Backpatching can be used to generate code for flow-of-control statements in one pass. 
Which ONE of the following options is CORRECT?

Consider the augmented grammar with \(\{+,* , (, ), id\}\) as the set of terminals. \[ S' \rightarrow S \] \[ S \rightarrow S + R \mid R \] \[ R \rightarrow R^{\,*} P \mid P \] \[ P \rightarrow (S) \mid id \] If \(I_0\) is the set of two LR(0) items \(\{[S' \rightarrow S.], [S \rightarrow S. + R]\}\), then \(goto(\text{closure}(I_0), +)\) contains exactly \(\underline{\hspace{1cm}}\) items.

Consider the following grammar along with translation rules. \[ S \rightarrow S_1 \# T \,\,\,\,\,\,\{S_{\centerdot\text{val}} = S_{1\centerdot\text{val}}* T_{\centerdot\text{val}}\} \] \[ S \rightarrow T \,\,\,\,\,\,\{S_{\centerdot\text{val}} = T_{\centerdot\text{val}}\} \] \[ T \rightarrow T_1 \% R \,\,\,\,\,\, \{T_{\centerdot\text{val}} = T_{1\centerdot\text{val}} \div R_{\centerdot\text{val}}\} \] \[ T \rightarrow R \,\,\,\,\,\,\{T_{\centerdot\text{val}} = R_{\centerdot\text{val}}\} \] \[ R \rightarrow \text{id} \,\,\,\,\,\,\{R_{\centerdot\text{val}} = \text{id}_{\centerdot\text{val}}\} \] Here \(\#\) and % are operators and id is a token that represents an integer and \( \text{id}_{\text{val}} \) represents the corresponding integer value. The set of non-terminals is {S, T, R, P}, and a subscripted non-terminal indicates an instance of the non-terminal.
Using this translation scheme, the computed value of} \( S_{\text{val}} \) for root of the parse tree for the expression \(20\#10%5\#8%2\#2 \) is

Consider the following C code segment: 

a = b + c; 
e = a + 1; 
d = b + c; 
f = d + 1; 
g = e + f; 

In a compiler, this code is represented internally as a Directed Acyclic Graph (DAG). The number of nodes in the DAG is \(\underline{\hspace{2cm}}\).

Consider the following context-free grammar where the set of terminals is \(\{a,b,c,d,f\}\): 
\[ S \rightarrow daT \mid Rf \] \[ T \rightarrow aS \mid baT \mid \epsilon \] \[ R \rightarrow caTR \mid \epsilon \] The following is a partially-filled LL(1) parsing table. 

Which one of the following choices represents the correct combination for the numbered cells in the parsing table ("blank" denotes that the corresponding cell is empty)? 

Consider the following grammar (that admits a series of declarations, followed by expressions) and the associated syntax directed translation (SDT) actions, given as pseudo-code:

P → D* E*
D → int ID {record that ID.lexeme is of type int}
D → bool ID {record that ID.lexeme is of type bool}
E → E₁ + E₂ {check that E₁.type = E₂.type = int; set E.type := int}
E → !E₁ {check that E₁.type = bool; set E.type := bool}
E → ID {set E.type := int}

With respect to the above grammar, which one of the following choices is correct?

Consider the following augmented grammar with terminals {#, @, <, >, a, b, c}.

$S' → S$
$S → S\#cS$
$S → SS$
$S → S@$
$S → <S>$
$S → a$
$S → b$
$S → c$

Let I₀ = CLOSURE({ S' → • S }). The number of items in the set GOTO(GOTO(I₀, <), <) is  .