GATE CSE Runtime Environments PYQs
In Compiler Design, GATE tests Runtime Environments through conceptual and tracing questions on activation records, procedure activation trees, runtime memory a… Read the guide
- Questions
- 7
- Asked
- 2012–2023
- Total marks
- 10
- Marks / paper
- 0.4
7 GATE CSE Runtime Environments PYQs with solutions, from Compiler Design. Browse all GATE CSE PYQs.
Questions
Every official paper that asked this topic, newest first.
- GATE CSE 2023 · Q36Consider the following program:
int main() { f1(); f2(2); f3(); return(0); } int f1() { return(1); } int f2(int X) { f3(); if (X==1) return f1(); else return (X*f2(X-1)); } int f3() { return(5); }Which one of the following options represents the…MCQ2 marksMediumSolve - GATE CSE 2021 Set 1 · Q4Consider the following statements. The sequence of procedure calls corresponds to a preorder traversal of the activation tree. The sequence of procedure returns corresponds to a postorder traversal of the activation tree. Which one of the following options is correct?MCQ1 markEasySolve
- GATE CSE 2020 · Q9Consider the following statements. I. Symbol table is accessed only during lexical analysis and syntax analysis. II. Compilers for programming languages that support recursion necessarily need heap storage for memory allocation in the run-time environment. III. Errors violating the condition ‘any variable must be…MCQ1 markMediumSolve
- GATE CSE 2016 Set 1 · Q36What will be the output of the following pseudo-code when parameters are passed by reference and dynamic scoping is assumed?
a=3; void n(x) {x = x * a; print(x);} void m(y) {a = 1; a = y - a; n(a); print(a);} void main() {m(a);}MCQ2 marksMediumSolve - GATE CSE 2014 Set 2 · Q18Which one of the following is NOT performed during compilation?MCQ1 markEasySolve
- GATE CSE 2014 Set 3 · Q18Which of the following statements are CORRECT? 1) Static allocation of all data areas by a compiler makes it impossible to implement recursion. 2) Automatic garbage collection is essential to implement recursion. 3) Dynamic allocation of activation records is essential to implement recursion. 4) Both heap and stack…MCQ1 markMediumSolve
- GATE CSE 2012 · Q36Consider 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.…MCQ2 marksMediumSolve
What GATE tests in Runtime Environments
Concepts, patterns, formulas and traps distilled from past papers.
In Compiler Design, GATE tests Runtime Environments through conceptual and tracing questions on activation records, procedure activation trees, runtime memory allocation strategies (static vs. stack vs. heap), and scoping rules combined with parameter-passing mechanisms. Questions alternate between 1-mark theoretical concept validation (e.g., requirements for recursion, activation tree traversals) and 2-mark procedural traces (e.g., determining static access links, program output under dynamic scoping, and activation tree construction).
Core concepts
- Activation tree representation and tree traversals (preorder for calls, postorder for returns)
- Activation records (stack frames) and their layout (control links, access links, local data, parameters)
- Static (access) links for lexical scoping vs. dynamic (control) links for caller tracking
- Runtime memory allocation strategies (static allocation, stack allocation, heap allocation)
- Minimum storage requirements to support recursion (dynamic call stack vs. static data areas)
- Scoping semantics (Lexical/Static scoping vs. Dynamic scoping)
- Parameter passing mechanisms (Pass by value, Pass by reference, Aliasing)
- Phase separation: compile-time tasks (type checking, symbol table management) vs. runtime tasks (dynamic memory allocation)
Recurring question patterns
Activation Tree Structure and Traversal Properties
CommonMCQ1.5 marks2023, 2021Given a program with nested or recursive calls, determine its activation tree structure or identify the relationship between call/return sequences and tree traversal orders (preorder/postorder).
Runtime Memory Allocation and Recursion Requirements
CommonMCQ1 marks2020, 2014Evaluating statements regarding static allocation, dynamic stack allocation, heap allocation, and garbage collection in the context of recursion and procedure execution.
Access Links (Static Links) in Nested Lexical Scopes
OccasionalMCQ2 marks2012Given a block-structured pseudo-language program with nested procedures and a specific dynamic calling chain, identify the correct static/access links in the activation record stack.
Code Tracing with Scoping and Parameter Passing
OccasionalMCQ2 marks2016Tracing program execution to compute printed output when combinations of static vs. dynamic scoping and pass-by-value vs. pass-by-reference are specified.
Formulas GATE uses
Procedure Call Sequence Traversal
Used when relating the chronological order of entering procedure activations to activation tree traversals.
Procedure Return Sequence Traversal
Used when relating the chronological order of procedure completions/returns to activation tree traversals.
Access Link (Static Link) Pointer Target
Used to find non-local variable environments under lexical (static) scoping regardless of dynamic caller.
Examiner traps in Runtime Environments
- Confusing static/access links (pointing to the immediate lexical parent scope) with dynamic/control links (pointing to the calling procedure's frame).
- Believing recursion requires dynamic heap allocation or garbage collection rather than simply a dynamic call stack.
- Swapping activation tree traversal orders (thinking calls are postorder and returns are preorder).
- Under dynamic scoping, resolving free variables using lexical parent blocks instead of walking up the active runtime call stack.
- Forgetting aliasing effects in pass-by-reference when the same variable is passed to multiple parameters or passed to a function that mutates the outer variable directly.
How questions are asked
- Identify correct activation tree for a multi-function/recursive program
- Determine the static link pointers in a stack of activation records given a call sequence
- Trace output under dynamic scoping and pass-by-reference
- Multi-statement correctness evaluation on runtime environments and recursion requirements
Paper trends
Shift from tracing nested access links and dynamic scope code execution to formal graph-theoretic properties of activation trees (traversals and call tree generation).
2023, 2021, 2016, 2012
Consistent focus on testing misconceptions around runtime storage requirements for recursion (specifically establishing that call stacks are necessary while heaps and garbage collection are not).
2020, 2014
Difficulty notes
Easy questions (1 mark) test standard runtime environment definitions (e.g., distinguishing compile-time from runtime activities, activation tree traversal identities). Medium questions (1-2 marks) involve tracing non-trivial recursive execution to produce activation trees, tracing multi-scope variable mutations under dynamic scoping with references, or analyzing static access link pointers across deep lexical nesting.