Compiler Design Solved MCQs- Part 2

The output of lexical analyzer is A set of regular expressions Syntax tree Set of tokens Strings of character       _____________________________________________________________________________________

If conversion from one type to another type is done automatically by the compiler then,it is called Implicit conversion coercions both a and b None of the above       _____________________________________________________________________________________

Syntax directed translation scheme is desirable because  It is based on the syntax Its description is independent of any implementation It is easy to modify All of these       _____________________________________________________________________________________

A top down parser generates  Right most derivation Right most derivation in reverse Left most derivation Left most derivation in reverse       _____________________________________________________________________________________

Macro-processors are ______ Hardware Compiler Registers None of the above       _____________________________________________________________________________________

Inherited attribute is a natural choice in Keeping track of variable declaration Checking for the correct use of L values and R values Both A and B None of these       _____________________________________________________________________________________

Concept which can be used to identify loops is  Dominators Reducible graphs Depth first ordering All of these       _____________________________________________________________________________________

Reduction in strength means  Replacing run time computation by compile time computation Removing loop invariant computation Removing common sub expression Replacing a costly operation by a relatively cheaper one       _____________________________________________________________________________________

the term environment in programming language semantics is said as function that maps a name to value held there Function that maps a name to storage location The functin that maps a storage location to the value held there None of the above       _____________________________________________________________________________________

A self relocating program is one which  cannot be made to execute in any area of storage other than the designated for it at the time of its coding or translation Consists of a program and relevant information for its relocation Can itself perform the relocation of its address sensitive protions All of the above       _____________________________________________________________________________________

The lexical analyzer takes_________as input and produces a stream of_______as output.  Source program,tokens Token,source program Either A and B None of the above       _____________________________________________________________________________________

Intermediate code generation phase gets input from  Lexical analyzer Syntax analyzer Semantic analyzer Error handling       _____________________________________________________________________________________

A grammar is meaningless  If terminal set and non terminal set are not disjoint If left hand side of a production is a single terminal If left hand side of a production has no non terminal All of these       _____________________________________________________________________________________

The optimization technique which is typically applied on loops is  Removal of invariant computation Peephole optimization Constant folding All of these       _____________________________________________________________________________________

resolution is externally defined symbols is performed by  linker loader compiler assembler       _____________________________________________________________________________________

Which of the following is used for grouping of characters into tokens? Parser Code optimization Code generator Lexical analyzer       _____________________________________________________________________________________

Whether a given pattern constitutes a token or not depends on the  Source language Target language Compiler All of these       _____________________________________________________________________________________

A optimizing compiler Is optimized to occupy less space Is optimized to take less time for execution Optimized the code None of the above.       _____________________________________________________________________________________

Which of the following symbols table implementation is based on the property of locality of reference? Hash table Search tree Self organizing list Linear list       _____________________________________________________________________________________

Three address code involves  Exactly 3 address At most most 3 address No unary operators None of these       _____________________________________________________________________________________

A B C D       _____________________________________________________________________________________

A compiler is  A program that place program into memory and prepares them for execution A program that automates the translation of assembly language into machine language program that accepts program written in high level language and produces an object program A program that appears to execute a source program as if it were machine language       _____________________________________________________________________________________

In a bottom up evaluation of a syntax direction definition ,inherited attributes can Always be evaluated Be evaluated only if the definition is L -attributed Be evaluated only if the definition has synthesized attributes None of the above       _____________________________________________________________________________________

Which of the following actions an operator precedence parser may take to recover from an error ? Insert symbols onto the stack Delete symbols from the stack Insert or delete symbols from the input All of the above       _____________________________________________________________________________________

DAG representation of a basic block allows Automatic detection of local common sub expressions Automatic detection of induction variables Automatic detection of loop variant None of the above       _____________________________________________________________________________________

Recursive descent parsing is an example  Top down parsing Bottom up parsing Predictive parsing None of the above       _____________________________________________________________________________________

The graph that shows basic blocks and their successor relationship is called DAG Flow chart Control graph Hamiltonian graph       _____________________________________________________________________________________

Generation of intermediate code based on a abstract machine model is useful in compilers because  it makes implementation of lexical analysis and syntax analysis easier syntax directed translation can be written for intermediate code generation. It enhances the portability of the front end of the compiler it is not possible to generate code for real machines directly from high level language programs       _____________________________________________________________________________________

Advantage of panic mode of error recovery is that  It is simple ti implement It never gets into an infinite loop Both A and B None of these       _____________________________________________________________________________________

In operator precedence parsing , precedence relations are defoned  For all pair of non terminals For all pair of terminals To delimit the handle Only for a certain pair of terminals       _____________________________________________________________________________________

An intermediate code form is Postfix notation Syntax trees Three address code All of these       _____________________________________________________________________________________

Code can be optimized at Source from user Target code Intermediate code All of the above       _____________________________________________________________________________________

Consider the program given below, in a block-structured pseudo-language with lexical scoping and nesting of procedures permitted. Program main; Var ... Procedure A1; Var ... Call A2; End A1 Procedure A2; Var ... Procedure A21; Var ... Call A1; End A21 Call A21; End A2 Call A1; End main. Consider the calling chain: Main -> A1 -> A2 -> A21 -> A1 The correct set of activation records along with their access links is given by A B C D       _____________________________________________________________________________________

Pee hole optimization Loop optimization Local optimization Constant folding Data flow analysis       _____________________________________________________________________________________

In which way(s) a macroprocessor for assembly language can be implemented ? Independent two-pass processor Independent one-pass processor Expand macrocalls and substitute arguments All of the above       _____________________________________________________________________________________

A compiler for a high level language that runs on one machine and produce code for different machine is called  Optimizing compiler One pass compiler Cross compiler Multipass compiler       _____________________________________________________________________________________

Which of the following is used for grouping of characters into tokens (in a computer) A parser Code optimizer Code generator Scanner       _____________________________________________________________________________________

Local and loop optimization in turn provide motivation for  Data flow analysis Constant folding Pee hole optimization DFA and constant folding       _____________________________________________________________________________________

A simple two-pass assembler does which of the following the first phase It allocates space for the literals. It computes the total length of the program. It builds the symbol table for the symbols and their values. All of above       _____________________________________________________________________________________

the translator is best described as Application software A system software A hardware component All of the above       _____________________________________________________________________________________

Which of the following is the most powerful parser?  SLR LALR Canonical LR Operator precedence       _____________________________________________________________________________________

Which of the following are language processors? Assembler Compilers interpreters All of these       _____________________________________________________________________________________

Relocating bits used by relocating loader are specified by  Relocating loader itself Linker Assembler Macro processor       _____________________________________________________________________________________

Synthesized attribute can be easily simulated by a LL grammar Ambiguous grammar LR grammar None of the above       _____________________________________________________________________________________

A compiler that runs on one machine and produces code for a different machine is called Cross compilation One pass compilation Two pass compilation None of the above       _____________________________________________________________________________________

_________or scanning is the process where the stream of characters making up the source program is read from left to right and grouped into tokens. Lexical analysis Diversion Modeling None of the above       _____________________________________________________________________________________

Input to code generator Source code Intermediate code Target code All of the above       _____________________________________________________________________________________

In analysis the compilation PL/I program the description Create of more optimal matrix is associated with  Assembly and output code generation Syntax analysis machine independent optimization       _____________________________________________________________________________________

A bottom up parser generates  right most derivation right most derivation in reverse left most derivation left most derivation in reverse       _____________________________________________________________________________________

In an absolute loading scheme which loader function is accomplished by assembler ? re-allocation allocation linking loading