Semantic Analysis - Crafting a Compiler - page 354

procedure (DoWhileLooping dwn )

dwn . loopBody . isReachable ← true

visit

dwn . terminatesNormally ← false

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call dwn . loopBody . accept( this )
constExprVisitor ←

26

new ConstExprVisitor()
call dwn . condition . accept( constExprVisitor )
conditionValue ← dwn . condition . exprValue

if conditionValue true
then
bodyNormal ← dwn . loopBody . terminatesNormally
dwn . terminatesNormally ← dwn . terminatesNormally or bodyNormal

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end

Figure 9.7: Reachability Analysis for a Do-While Statement

procedure (ForLooping fn )

fn . terminatesNormally ← true
fn . loopBody . isReachable ← true
if

visit

fn . condition null

then
constExprVisitor ← new ConstExprVisitor()

call fn . condition . accept( constExprVisitor )
conditionValue ← fn . condition . exprValue
if conditionValue = true
then

fn . terminatesNormally ← false

else
if conditionValue = false
then fn . loopBody . isReachable ← false
else fn . terminatesNormally ← false
call fn . loopBody . accept( this )
end

Figure 9.8: Reachability Analysis for a For Loop