2001 Paper 5 Question 6
Compiler Construction
Consider a language J which has
• Java-like syntax
• nested definitions of procedures within other procedures
• local variables (with static binding)
• raising and handling of named, parameterless exceptions
Explain a possible run-time data structure which a compiler for J might use.
[10 marks]
A na¨ıve user of such a language suggests that the resultant compiled code will spend
a significant fraction of execution time searching—both finding the store location
corresponding to the use of a variable name and finding the exception handler
corresponding to the raising of a given exception name.
Determine with justification whether this is so for your run-time data-structure
proposed above. [4 marks]
Now instead suppose a simple interpreter for J is written, so that searches for
variable (or exception) names search the appropriate environment for the variable
value or exception handler code. To what extent are these searches bounded by (a)
the number of variables or exceptions in the program or (b) the dynamic or static
nesting of procedures? [6 marks]