Compiler Design

Which of the following is the most powerful parser?

A top down parser generates

A shift reduce parser carries out the actions specified within braces immediately after reducing with the corresponding rule of grammar: $ S \rightarrow xxW $ {print "1"}, $ S \rightarrow y $ {print "2"}, $ S \rightarrow Sz $ {print "3"}. What is the translation of xxxxyzz using the syntax directed translation scheme described by the above rules?

Three-address code involves

Handle pruning forms the basis of

Left factoring guarantees

Consider a grammar $ A \rightarrow aS_1 | aS_2 $. The left factored grammar produced from the grammar is

Synthesized attributes are calculated

The method which merges the bodies of two loops is

For a grammar G, shift reduce (S-R) conflicts are present in LALR(1) parser, if and only if

Explain the working of each phase of compiler in detail with an example.

What is an activation record? Explain how they are used to access various local and global variables.

What are the advantages of LALR parsing over SLR and CLR methods?

Write the algorithm to compute FIRST and FOLLOW for a given grammar.

What is shift-reduce conflict?

Given the Syntax-Directed Definition below with the synthesized attribute val. Draw the annotated parse tree for the expression $ (3+4)*(5+6) $:
$ L \rightarrow E $ ; $ L.val = E.val $
$ E \rightarrow T $ ; $ E.val = T.val $
$ E \rightarrow E_1 + T $ ; $ E.val = E_1.val + T.val $
$ T \rightarrow F $ ; $ T.val = F.val $
$ T \rightarrow T_1 * F $ ; $ T.val = T_1.val * F.val $
$ F \rightarrow (E) $ ; $ F.val = E.val $
$ F \rightarrow digit $ ; $ F.val = digit.lexval $

Find the FIRST and FOLLOW from the following production:
$ S \rightarrow aBDh $
$ B \rightarrow cC $
$ C \rightarrow bC | \epsilon $
$ D \rightarrow EF $
$ E \rightarrow g | \epsilon $
$ F \rightarrow f | \epsilon $

Construct the predictive parsing table for the following grammar:
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$ C \rightarrow cg $

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement: $ a = (a*b+c)\wedge(b+c)*b+c $

What is handle? Consider the grammar: $ E \rightarrow E+E | E*E | id $. Find the handles of the right sentential forms of the reduction for the string $ id_1 + id_2 * id_3 $.

When a grammar is called ambiguous? Is there any technique to remove ambiguity? Justify whether the grammar is ambiguous or not: $ A \rightarrow AA | (A) | a $

Discuss about operator precedence parser.

Differentiate between S-attribute SDT and L-attribute SDT with suitable examples.

Consider the following grammar: $ E \rightarrow E+T | T $, $ T \rightarrow T*F | F $, $ F \rightarrow id $. Draw a SLR state transition diagram for the above grammar. Also draw the SLR parse table.

Consider the following grammar: $ S \rightarrow CC $, $ C \rightarrow cC | d $. Find the LR(1) set of items.

Translate the expression $ a=(a+b)*(c+d)+(a+b+c) $ into (i) Quadruple (ii) Triple (iii) Indirect triple.

Which of the following is the most powerful parser?

A top down parser generates

A shift reduce parser carries out the actions specified within braces immediately after reducing with the corresponding rule of grammar: $S \rightarrow xxW$ {print "1"}, $ S \rightarrow y ${print "2"},$ S \rightarrow Sz $ {print "3"}. What is the translation of xxxxyzz using the syntax directed translation scheme described by the above rules?

Three-address code involves

Handle pruning forms the basis of

Left factoring guarantees

Consider a grammar $A \rightarrow aS_1 | aS_2$. The left factored grammar produced from the grammar is

Synthesized attributes are calculated

The method which merges the bodies of two loops is

For a grammar G, shift reduce (S-R) conflicts are present in LALR(1) parser, if and only if

Explain the working of each phase of compiler in detail with an example.

What is an activation record? Explain how they are used to access various local and global variables.

What are the advantages of LALR parsing over SLR and CLR methods?

Write the algorithm to compute FIRST and FOLLOW for a given grammar.

What is shift-reduce conflict?

Given the Syntax-Directed Definition below with the synthesized attribute val. Draw the annotated parse tree for the expression $(3+4)*(5+6)$:
$L \rightarrow E$ ; $ L.val = E.val $
$E \rightarrow T$ ; $ E.val = T.val $
$E \rightarrow E_1 + T$ ; $ E.val = E_1.val + T.val $
$T \rightarrow F$ ; $ T.val = F.val $
$T \rightarrow T_1 * F$ ; $ T.val = T_1.val * F.val $
$F \rightarrow (E)$ ; $ F.val = E.val $
$F \rightarrow digit$ ; $F.val = digit.lexval$

Find the FIRST and FOLLOW from the following production:
$ S \rightarrow aBDh $
$ B \rightarrow cC $
$ C \rightarrow bC | \epsilon $
$ D \rightarrow EF $
$ E \rightarrow g | \epsilon $
$F \rightarrow f | \epsilon$

Construct the predictive parsing table for the following grammar:
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$C \rightarrow cg$

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement: $a = (a*b+c)\wedge(b+c)*b+c$

What is handle? Consider the grammar: $E \rightarrow E+E | E*E | id$. Find the handles of the right sentential forms of the reduction for the string $id_1 + id_2 * id_3$.

When a grammar is called ambiguous? Is there any technique to remove ambiguity? Justify whether the grammar is ambiguous or not: $A \rightarrow AA | (A) | a$

Discuss about operator precedence parser.

Differentiate between S-attribute SDT and L-attribute SDT with suitable examples.

Consider the following grammar: $E \rightarrow E+T | T$, $T \rightarrow T*F | F$, $F \rightarrow id$. Draw a SLR state transition diagram for the above grammar. Also draw the SLR parse table.

Consider the following grammar: $S \rightarrow CC$, $C \rightarrow cC | d$. Find the LR(1) set of items.

Translate the expression $a=(a+b)*(c+d)+(a+b+c)$ into (i) Quadruple (ii) Triple (iii) Indirect triple.

• LEX and YACC
• Peephole Optimization
• Symbol Table
• Predictive parser

Which of the following derivations does a top-down parser use while parsing an input string? The input is assumed to be scanned in left to right order.

What is the maximum number of reduce moves that can be taken by a bottom-up parser for a grammar with no epsilon- and unit-production (i.e., of type $ A \rightarrow \epsilon $ and $ A \rightarrow a $) to parse a string with n tokens?

In a bottom-up evaluation of a syntax directed definition, inherited attributes can

Consider the grammar shown below : $ S \rightarrow CC $, $ C \rightarrow cC | d $. The grammar is

The lexical analyzer takes _____ as input and produces a stream of _____ as output.

In a compiler, when is the keywords of a language are recognized?

How many tokens are there in the following C statement?
printf("j=%d, & j=%x", j, & j)

How is the parsing precedence relation defined?

Given the following expression grammar : $ E \rightarrow E*F | F+E | F $, $ F \rightarrow F-F | id $. Which of the following is true?

Shift reduce parsers are

Write a lexical analyzer program to identify strings, sequences, comments, reserved words and identifiers.

Explain about the sources and criterions of code optimization as machine dependent and independent types.

Construct the non-recursive predictive parse table for the given grammar and check the acceptance of input string "abfcg":
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$ C \rightarrow cg $

What is the relationship with lexical analyzer, regular expressions and transition diagram? Give an example.

Explain the type system in type checker. Write the syntax directed definition for type checker.

What is activation record? Explain its usage in stack allocation strategy. How is it different from heap allocation?

Draw and explain the runtime memory organization static storage allocation strategy with pros and cons.

Differentiate inherited and synthesized attributes with an example.

Define dataflow analysis. List out the procedures to analyze the data flow of structured programs.

Draw a block diagram of phases of a compiler and indicate the main functions of each phase.

What is intermediate code? Translate the expression $ (a+b)/(c+d)*(a+b/c)-d $ into quadruples, triples and indirect triples.

Explain reducible and non-reducible flow graphs with an example each.

What is machine-dependent optimization? Explain how peephole techniques function in this.

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement: $ a=(a*b+c)\wedge(b+c)*b+c $

Which of the following derivations does a top-down parser use while parsing an input string? The input is assumed to be scanned in left to right order.

What is the maximum number of reduce moves that can be taken by a bottom-up parser for a grammar with no epsilon- and unit-production (i.e., of type $A \rightarrow \epsilon$ and $ A \rightarrow a $) to parse a string with n tokens?

In a bottom-up evaluation of a syntax directed definition, inherited attributes can

Consider the grammar shown below : $S \rightarrow CC$, $C \rightarrow cC | d$. The grammar is

The lexical analyzer takes _____ as input and produces a stream of _____ as output.

In a compiler, when is the keywords of a language are recognized?

How many tokens are there in the following C statement?
printf("j=%d, & j=%x", j, & j)

How is the parsing precedence relation defined?

Given the following expression grammar : $E \rightarrow E*F | F+E | F$, $ F \rightarrow F-F | id $. Which of the following is true?

Shift reduce parsers are

Write a lexical analyzer program to identify strings, sequences, comments, reserved words and identifiers.

Explain about the sources and criterions of code optimization as machine dependent and independent types.

Construct the non-recursive predictive parse table for the given grammar and check the acceptance of input string "abfcg":
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$C \rightarrow cg$

What is the relationship with lexical analyzer, regular expressions and transition diagram? Give an example.

Explain the type system in type checker. Write the syntax directed definition for type checker.

What is activation record? Explain its usage in stack allocation strategy. How is it different from heap allocation?

Draw and explain the runtime memory organization static storage allocation strategy with pros and cons.

Differentiate inherited and synthesized attributes with an example.

Define dataflow analysis. List out the procedures to analyze the data flow of structured programs.

Draw a block diagram of phases of a compiler and indicate the main functions of each phase.

What is intermediate code? Translate the expression $(a+b)/(c+d)*(a+b/c)-d$ into quadruples, triples and indirect triples.

Explain reducible and non-reducible flow graphs with an example each.

What is machine-dependent optimization? Explain how peephole techniques function in this.

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement: $a=(a*b+c)\wedge(b+c)*b+c$

• Function preserving optimization techniques
• Reference counting garbage collectors
• Elimination of loop invariant variable
• Strength reduction

When is the type checking usually done?

Which one of the following statements is true?

In a compiler, _____ checks every character of the source text.

For a grammar G, shift reduce (S-R) conflicts are present in LALR(1) parser, if and only if

In an absolute loading scheme, which loader function is accomplished by programmer?

_____ is a top-down parser.

The languages that need heap allocation in the runtime environment are those that

In compilers, generation of intermediate code based on an abstract machine model is useful because

To convert an arbitrary CFG to an LL(1) grammar

The method which merges the bodies of two loops is

What is an activation record? Explain how they are used to access various local and global variables.

What is bottom-up parsing? Discuss shift reduce parsing technique in brief. What is a handle?

What is left recursion? Eliminate the left recursion from the following grammar:
$ E \rightarrow E+T | T $
$ T \rightarrow T*F | F $
$ F \rightarrow (E) | id $

What is the use of a symbol table? How are the identifiers stored in the symbol table?

What is the pass of a compiler? Explain how the single- and multi-pass compilers work.

Explain architecture and algorithm for the non-recursive predictive parser.

Check whether the following grammar is CLR or not:
$ S \rightarrow Aa | bBa | Ba | bAc $
$ A \rightarrow c $
$ B \rightarrow d $

What is the syntax directed translation and why are they important?

Explain different phases of compiler.

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement:
$ a=(a*b+c)\wedge(b+c)*b+c $

Explain various targets for code optimization with examples.

How are CPU registers allocated while creating machine code?

Check whether the following grammar is LL(1) grammar or not:
$ S \rightarrow iEtSA | a $
$ A \rightarrow eS | \epsilon $
$ E \rightarrow b $

Design the FIRST SET and FOLLOW SET for the grammar.

Differentiate between S-attribute SDT and L-attribute SDT with suitable examples.

Explain any two of the following:

When is the type checking usually done?

Which one of the following statements is true?

In a compiler, _____ checks every character of the source text.

For a grammar G, shift reduce (S-R) conflicts are present in LALR(1) parser, if and only if

In an absolute loading scheme, which loader function is accomplished by programmer?

_____ is a top-down parser.

The languages that need heap allocation in the runtime environment are those that

In compilers, generation of intermediate code based on an abstract machine model is useful because

To convert an arbitrary CFG to an LL(1) grammar

The method which merges the bodies of two loops is

What is an activation record? Explain how they are used to access various local and global variables.

What is bottom-up parsing? Discuss shift reduce parsing technique in brief. What is a handle?

What is left recursion? Eliminate the left recursion from the following grammar:
$ E \rightarrow E+T | T $
$ T \rightarrow T*F | F $
$ F \rightarrow (E) | id $

What is the use of a symbol table? How are the identifiers stored in the symbol table?

What is the pass of a compiler? Explain how the single- and multi-pass compilers work.

Explain architecture and algorithm for the non-recursive predictive parser.

Check whether the following grammar is CLR or not:
$ S \rightarrow Aa | bBa | Ba | bAc $
$ A \rightarrow c $
$ B \rightarrow d $

What is the syntax directed translation and why are they important?

Explain different phases of compiler.

Explain how type checking and error reporting are performed in compiler. Draw syntax tree and DAG for the statement:
$ a=(a*b+c)\wedge(b+c)*b+c $

Explain various targets for code optimization with examples.

How are CPU registers allocated while creating machine code?

Check whether the following grammar is LL(1) grammar or not:
$ S \rightarrow iEtSA | a $
$ A \rightarrow eS | \epsilon $
$ E \rightarrow b $

Design the FIRST SET and FOLLOW SET for the grammar.

Differentiate between S-attribute SDT and L-attribute SDT with suitable examples.

Explain any two of the following:

What is the number of tokens in the following C statement? printf("I=%d and I=%x",I and I)

Consider the following two statements: P: Every regular grammar is LL(1). Q: Every regular set has LR(1) grammar. Which of the following is true?

What is the similarity between LR, LALR and SLR?

Consider the following grammar: $ S \rightarrow aSbS | bSaS | \epsilon $. How many different parse trees are possible for string ababab?

A shift reduce parser carries out the actions specified within braces immediately after reducing with the corresponding rule of grammar: $ S \rightarrow xxW $ {PRINT "1"}, $ S \rightarrow y $ {print "2"}, $ S \rightarrow Sz $ {print "3"}. What is the translation of xxxxyzz using the syntax directed translation scheme described by the above rules?

The most powerful parser is

In some programming languages, an identifier is permitted to be a letter followed by any number of letters or digits. If L and D denote the sets of letters and digits respectively, which of the following expressions defines an identifier?

In operator precedence parsing, precedence relations are defined

A bottom-up parser generates

A grammar that produces more than one parse tree for some sentence is called

What do you understand by left recursion and left factoring? How are these eliminated? Explain with the help of suitable example.

What do you understand by bootstrapping? Explain with the help of suitable example.

How can addressing modes be used for reducing the memory access time?

What are activation records? Explain its purpose in compilers.

What are the optimization techniques applied on procedures calls? Explain with an example.

Given the Syntax-Directed Definition below with the synthesized attribute val. Draw the annotated parse tree for the expression $ (3+4)*(5+6) $:
$ L \rightarrow E $ ; $ L.val = E.val $
$ E \rightarrow T $ ; $ E.val = T.val $
$ E \rightarrow E_1+T $ ; $ E.val = E_1.val+T.val $
$ T \rightarrow F $ ; $ T.val = F.val $
$ T \rightarrow T_1*F $ ; $ T.val = T_1.val*F.val $
$ F \rightarrow (E) $ ; $ F.val = E.val $
$ F \rightarrow digit $ ; $ F.val = digit.lexval $

Construct a Syntax-Directed Translation scheme that translates arithmetic expressions from infix into postfix notation. Your solution should include the context-free grammar, the semantic attributes for each of the grammar symbols, and semantic rules. Show the application of your scheme to the input "3*4+5*2".

What is the advantage of using machine independent intermediate representation during translation process?

Explain, with example, what three address codes are. Give some common three address statements.

Find the three address codes of the following program. There are four bytes per word:
Sum = 0
For(i = 1; i <= 20; i++)
Sum = Sum + a[i] + b[i];

Find the CNF (Chomsky Normal Form) for the following CFG:
$ S \rightarrow ABA $
$ A \rightarrow aA | \epsilon $
$ B \rightarrow bB | \epsilon $

Eliminate null productions from the following CFG:
$ S \rightarrow Xa $
$ X \rightarrow aX | bX | \epsilon $

Convert the following grammar to GNF :
$ A_1 \rightarrow A_2A_3 $
$ A_2 \rightarrow A_3A_1 | b $
$ A_3 \rightarrow A_1A_2 | a $

What are the advantages of LALR parsing over SLR and CLR methods?

Write the algorithm to compute FIRST and FOLLOW for a given grammar.

What is shift-reduce conflict?

What are intermediate codes in compilers? Why is it needed in compiler design? Discuss different types of intermediate codes generated by intermediate code generation phase.

What is parsing? What is the difference between Top-down parsing, Bottom-up parsing and Predictive parsing?

Explain the working of each phase of compiler in detail with an example.

What is the number of tokens in the following C statement? printf("I=%d and I=%x",I and I)

Consider the following two statements: P: Every regular grammar is LL(1). Q: Every regular set has LR(1) grammar. Which of the following is true?

What is the similarity between LR, LALR and SLR?

Consider the following grammar: $ S \rightarrow aSbS | bSaS | \epsilon $. How many different parse trees are possible for string ababab?

A shift reduce parser carries out the actions specified within braces immediately after reducing with the corresponding rule of grammar: $ S \rightarrow xxW $ {PRINT "1"}, $ S \rightarrow y $ {print "2"}, $ S \rightarrow Sz $ {print "3"}. What is the translation of xxxxyzz using the syntax directed translation scheme described by the above rules?

The most powerful parser is

In some programming languages, an identifier is permitted to be a letter followed by any number of letters or digits. If L and D denote the sets of letters and digits respectively, which of the following expressions defines an identifier?

In operator precedence parsing, precedence relations are defined

A bottom-up parser generates

A grammar that produces more than one parse tree for some sentence is called

What do you understand by left recursion and left factoring? How are these eliminated? Explain with the help of suitable example.

What do you understand by bootstrapping? Explain with the help of suitable example.

How can addressing modes be used for reducing the memory access time?

What are activation records? Explain its purpose in compilers.

What are the optimization techniques applied on procedures calls? Explain with an example.

Given the Syntax-Directed Definition below with the synthesized attribute val. Draw the annotated parse tree for the expression $ (3+4)*(5+6) $:
$ L \rightarrow E $ ; $ L.val = E.val $
$ E \rightarrow T $ ; $ E.val = T.val $
$ E \rightarrow E_1+T $ ; $ E.val = E_1.val+T.val $
$ T \rightarrow F $ ; $ T.val = F.val $
$ T \rightarrow T_1*F $ ; $ T.val = T_1.val*F.val $
$ F \rightarrow (E) $ ; $ F.val = E.val $
$ F \rightarrow digit $ ; $ F.val = digit.lexval $

Construct a Syntax-Directed Translation scheme that translates arithmetic expressions from infix into postfix notation. Your solution should include the context-free grammar, the semantic attributes for each of the grammar symbols, and semantic rules. Show the application of your scheme to the input "3*4+5*2".

What is the advantage of using machine independent intermediate representation during translation process?

Explain, with example, what three address codes are. Give some common three address statements.

Find the three address codes of the following program. There are four bytes per word:
Sum = 0
For(i = 1; i <= 20; i++)
Sum = Sum + a[i] + b[i];

Find the CNF (Chomsky Normal Form) for the following CFG:
$ S \rightarrow ABA $
$ A \rightarrow aA | \epsilon $
$ B \rightarrow bB | \epsilon $

Eliminate null productions from the following CFG:
$ S \rightarrow Xa $
$ X \rightarrow aX | bX | \epsilon $

Convert the following grammar to GNF :
$ A_1 \rightarrow A_2A_3 $
$ A_2 \rightarrow A_3A_1 | b $
$ A_3 \rightarrow A_1A_2 | a $

What are the advantages of LALR parsing over SLR and CLR methods?

Write the algorithm to compute FIRST and FOLLOW for a given grammar.

What is shift-reduce conflict?

What are intermediate codes in compilers? Why is it needed in compiler design? Discuss different types of intermediate codes generated by intermediate code generation phase.

What is parsing? What is the difference between Top-down parsing, Bottom-up parsing and Predictive parsing?

Explain the working of each phase of compiler in detail with an example.

A grammar that produces more than one parse tree for some sentence is said to be

What is not the phase of a compiler?

Given a grammar $ G=(\{E\}, \{id, +\}, P, E) $; where P is given by $ E \rightarrow E+E | id $. Then FOLLOW(E) will contain

Which of the following expressions has no l-value?

Consider the statement "fi (x>=10)", where 'if' has been misspelled. The error is detected by the compiler in the phase

Which of the following is not a loop optimization?

If x is a terminal then FIRST(x) is

Consider following grammar $ S \rightarrow cAd $, $ A \rightarrow ab | a $. For input string cad, how many times the recursive descent parser will backtrack?

The optional access link in the activation record is used for

Suppose two productions are there: $ A \rightarrow \alpha $ and $ A \rightarrow \beta $. The recursive descent parsing without backtracking requires:

Construct DFA for $ (ab^* | ba^*) $ and minimize the number of states of the above constructed DFA.

A grammar is given below:
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$ C \rightarrow g $
Find the FIRST and FOLLOW set.

Construct a predictive parsing table for the grammar given above.

What is a symbol table? Why is it needed in compiler design? Explain different components of a symbol table with an example.

Consider the following program fragment:
prod = 0;
i = 1;
do {
    prod = prod + a[i] * b[i];
    i = i + 1;
} while (i <= 20);
Generate the three-address code for the above program fragment.

Determine the basic blocks for the computed three-address code.

What is DAG? What is the use of DAG in compiler construction? Construct a DAG for the following statements:
$ Z = X - Y + X * Y $
$ U = V / W + X + V $

Explain peephole optimization in detail.

Suppose a basic block is formed from the C assignment statements:
$ x = a + b + c + d + e + f; $
$ y = a + c + e; $
(a) Give the three-address statements (only one addition per statement) for this block.
(b) Use the associative and commutative laws to modify the block to use the fewest possible number of instructions, assuming both $ x $ and $ y $ are live on exit from the block.

Given the grammar $ G = (S, \{S, A, B\}, \{a, b, c, d\}, P) $ with set of productions $ P $ below compute;

                </p><p>a. LR(1) sets of items.</p>

b. Compute the corresponding parsing table for the corresponding shift-reduce parse engine.

c. Show the actions of the parsing engine as well as the contents of the symbol and state stacks for the input string $ w = \text{"bdac"} $.

d. Is this grammar LALR(1)? Justify.

A grammar that produces more than one parse tree for some sentence is said to be

What is not the phase of a compiler?

Given a grammar $ G=(\\{E\\}, \\{id, +\\}, P, E) $; where P is given by $ E \rightarrow E+E | id $. Then FOLLOW(E) will contain

Which of the following expressions has no l-value?

Consider the statement "fi (x>=10)", where 'if' has been misspelled. The error is detected by the compiler in the phase

Which of the following is not a loop optimization?

If x is a terminal then FIRST(x) is

Consider following grammar $ S \rightarrow cAd $, $ A \rightarrow ab | a $. For input string cad, how many times the recursive descent parser will backtrack?

The optional access link in the activation record is used for

Suppose two productions are there: $ A \rightarrow \alpha $ and $ A \rightarrow \beta $. The recursive descent parsing without backtracking requires:

Construct DFA for $ (ab^* | ba^*) $ and minimize the number of states of the above constructed DFA.

A grammar is given below:
$ S \rightarrow A $
$ A \rightarrow aB | Ad $
$ B \rightarrow bBC | f $
$ C \rightarrow g $
Find the FIRST and FOLLOW set.

Construct a predictive parsing table for the grammar given above.

What is a symbol table? Why is it needed in compiler design? Explain different components of a symbol table with an example.

Consider the following program fragment:
prod = 0;
i = 1;
do {
    prod = prod + a[i] * b[i];
    i = i + 1;
} while (i <= 20);
Generate the three-address code for the above program fragment.

Determine the basic blocks for the computed three-address code.

What is DAG? What is the use of DAG in compiler construction? Construct a DAG for the following statements:
$ Z = X - Y + X * Y $
$ U = V / W + X + V $

Explain peephole optimization in detail.

Suppose a basic block is formed from the C assignment statements:
$ x = a + b + c + d + e + f; $
$ y = a + c + e; $
(a) Give the three-address statements (only one addition per statement) for this block.
(b) Use the associative and commutative laws to modify the block to use the fewest possible number of instructions, assuming both $ x $ and $ y $ are live on exit from the block.

Given the grammar $ G = (S, \\{S, A, B\\}, \\{a, b, c, d\\}, P) $ with set of productions $ P $ below compute;

                </p><p>a. LR(1) sets of items.</p>

b. Compute the corresponding parsing table for the corresponding shift-reduce parse engine.

c. Show the actions of the parsing engine as well as the contents of the symbol and state stacks for the input string $ w = \text{"bdac"} $.

d. Is this grammar LALR(1)? Justify.