Static Single Assignment (SSA) form requires that:
SSA gives each definition a distinct versioned name, so every SSA variable/version has exactly one defining assignment. A source-level variable may therefore correspond to multiple SSA versions.
In SSA representation, what special operator is placed at control flow join points (e.g. after an if-else) to select a variable value based on the incoming control flow path?
A $\Phi ($\(\phi\)) function merges different versions of a variable originating from multiple control flow paths at join points in an SSA graph.
Which SDT translation scheme strategy allows inherited attributes to be evaluated during top-down LL(1) parsing without building an explicit parse tree?
L-attributed definitions evaluate left-to-right. Semantic actions can be placed embedded inside production RHS body locations in top-down LL parsers.
What is the postfix notation for the infix expression a + b * c - d / e?
Precedence: b * c -> b c *. Then a + (b c *) -> a b c * +. d / e -> d e /. Subtraction -> a b c * + d e / -.
In syntax-directed translation, what is a Parse Tree dependency graph used for?
A dependency graph draws directed edges from source attributes to target attributes. A topological sort on this graph gives a valid attribute evaluation order.