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Sixth Semester R.E. Degree Examination, Dec. $09$ lJan. $10$

Compiler Design

Time: 3 $h r s .$

${Max}_{-}$ Marks: 100

Note: Answer any FIVEfull questions, setecling

at least TWO questions from each part.

PART $- A$

$\underline{\dot{8}}$ 1 $a$ . Explain a language processing system, with a block diagram. $(08 M a r k s ⟩$

$B$

$h_{-}$ $f_{\land}^{i}$ xplain the concept of input bufrering în the lexical analysis. $(0 \notin N I a ι \cdot k s ⟩$

$g$

$\underline{α}$ $c$ . Write the transition diagram to recognize the token relop. (Corre $S p o n$ ding to reIational

§

operators in a language). (06 Marks)

$π \infty$

$\circ Φ$ 2 $a$ . What is left‐recursion? Eliminate left recursion from the following grammar.

${\dot{α}}^{\tilde{α}} θ 1_{\sim} g$ $E \to E + T / T$ ; $T \to T * Γ / Γ$ ; $Γ \to (E ⟩ / i d$ $(0 ℏ$ Marks)

$\propto (, B \circ$ ' $b$ . Obtain the predictive parsing table for the followin $g$ grammar:

$¥ \bar{\bar{\cdot \underset{*}{\sim} \sim}}$ $S \to i E t S S' / a$ ; $S' \to e S l e$ ; $E \to b$ (14M$rrs)

$\frac{π}{R} Φ$ @u 3 $a$ . Obtain LR(O) items for the following grammar:

$c_{Φ}$

$\bar{c} *$

$S \to L = R / R$ ; $L \to * R / i d$ ; $R \to L$ (0$Marks $⟩$

${\tilde{c Γ}}^{ζ ∖ ↓}$

$\in^{τ_{-}}$

$b$ . Obtain first and follow symbols for the grammar shown in Q3 (a) and obtain @LR parsin $g$

$Φ$

$""$ $

tabls. Is the grammar SLR? $⟨ 12 M a r k s ⟩$

$\underline{= Φ}$ $

$o_{\emptyset^{⋁}} c \approx \bar{\geq}$ 4 $a$ . Given the following grammar:

$Φ α$

$s \to C C$ ; $C \to c C / d$

$c e$

$≃ \circ t f l α_{Φ}^{*}$ $i ⟩$ Construct sets ofLR(1) items.

$\circ 3 § g$ $i i ⟩$ $C c} n s ↑$ Juct canonical $l_{⋁} R (1)$ parsing tablf.

$(12 M a r k s ⟩$

$c^{\dot{O}} o, \subset 0 \approx \bar{n}$ $b$ . Constnict LALR parsing tables for the grammar shown in Q4 (a) using $L R (1 ⟩ i t e r n_{t^{08 M a r k s ⟩}} s .$

$g r$

$Γ_{\dot{Q}}$

PART $- B$

$\approx \geq \infty \tilde{\frac{B}{π}}$ 5 a Explain the concept ofsyntax directed translation2 with examples. $⟨ 06 M a r k s ⟩$

$\equiv > > Φ$ $b$ . Definc inherited and synthesized attributes. (O4Marks}

$\frac{\circ φ}{3} \frac{9}{ℏ}$ $c$ . Give SDD of $\cdot$ asimple desk calculator. (04 Marks)

$g a \propto$ $d_{*}$ Write the annotated parse tree for $2 * $ + 4 ι l_{*}$ $($ ( $i δ$ Marks)

8 $w$

$g_{O}^{* c^{-}}$ $S$ &. Draw $t h *$ IJAG for She ati $* b o e ε t i c$ expfession, $a * a^{s} (δ - ε ⟩ + (b \sim c)$ $•$ $δ$ . Show the $s^{⋁} t ε p s$ for

$* \geq \underline{\tilde{8}} Φ -$ constructing the DAG. $(1 θ$ Mark)

$C \overset{ˇ}{p}$

$b$ . What are three address codes? Explain different ways of representing three address $c {> d e s_{*}$

$\infty c$

$\sim α$

$\approx w$

with exampIes, $(1 θ B $ r $ @)$

$0 -$

$\infty B$

$⋁ \infty α_{Φ} {\underline{c}}_{ε}$ 7 $a$ . What is an activation record? Explain the purpose $< 2 f$ each item in the activation record $*$ with

$\frac{Φ}{a} \bar{\infty Φ}$ example. $(B M a r k s ⟩$

§ $\in$ g $b$ . Distinguish between static scopc and dynamic scope. $(U M \arg_{S})$

$a \approx \cdot ≷ \sim$ $c$ . What clo you rrnean by calling sequence? Explain the actions pedormed $d u c \dot{t} α g_{*} x$ ) function

$\sim \dot{\sim}$

call $i;$ ) rettrn. ($$ $ℜ$ ara)

$⋁ \ddot{Φ}$ § $a$ . Explain the niain issues in code generation. $⟨ 10 M a r k s ⟩$

$z o$

$b$ . For the following program segment:

$\tilde{\sim ♯ \in g \in}$ for $i = 1$ to 10 do

forj $= 1$ to 10 do

$a [i, j] = 0.0$

for $i = 1$ to 10 do

a[í, $i$ ] $= 1.0$

generate intermediate code and identi $θ$ basic bIocks.

(10 brarks}

$* * \cdot * *$

mathml