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return false;
}
if( get< Value >( converted ).isPoison() )
p.cfg()->poison();
// We need to know if the condition is constant true and this is an infinite loop:
// it means that no return is required after the while. In practice, that means
// we don't need to create a successor block and therefore won't leave it unterminated,
// which will prevent the higher level parsing code to complain about a missing return.
bool infiniteLoop = false;
// Try to eagerly evaluate the condition, if it happens to be constant true
// we need to know about it.
if( llr::CanValueBeEagerlyEvaluated( get< Value >( converted ) ) )
{
execute::VM vm;
auto cond = Evaluate( get< Value >( converted ), vm );
if( cond.isPoison() )
p.cfg()->poison();
else if( cond.isConstant() && *FromValue< bool >( cond ) )
infiniteLoop = true;
}
ptr< llr::BasicBlock > pHeaderBB;
// If this is an infinite loop, we don't need a header block: we can jump straight to the
// body.
if( !infiniteLoop )
pHeaderBB = p.cfg()->createBB();
// If this is an infinite loop, we don't need a header block: we can jump straight to the
// body.
if( infiniteLoop )
pHeaderBB = pBodyBB;
ptr< llr::BasicBlock > pSuccBB;
if( !infiniteLoop )
pSuccBB = p.cfg()->createBB();
{
// If there is a break somewhere, we are not an infinite loop after all.
// this doesn't affect that we don't need a header, but it means that we do need
// a successor block.
if( !pSuccBB )
pSuccBB = p.cfg()->createBB();
}
if( pSuccBB && !infiniteLoop )
{
// Emit the conditional branch that will either run an iteration of the loop or exit to the succ bb.
pHeaderBB->setTerminator( llr::CondBranch(
get< Value >( converted ),
pBodyBB, pSuccBB ) );
}
// If we have no successor BB, this will intetionally set the current BB to null.
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return false;
}
if( get< Value >( converted ).isPoison() )
p.cfg()->poison();
auto pHeaderBB = p.cfg()->createBB();
Parser::BreakableScopeGuard bsg( p );
Parser::ContinuableScopeGuard csg( p );
auto pBodyBB = ParseSubStatement( p, precedence::IfStmt );
if( !pBodyBB )
{
dm.emitSyntaxErrorMessage( p.resolver()->getCurrentLocation(), "expected a statement after the while condition.", 0 );
return false;
}
if( !pPrecBB )
return true;
// Retrieve the final block of the loop body, if any
if( auto pBodySuccBB = p.cfg()->currentBB(); pBodySuccBB && !pBodySuccBB->terminator() )
{
// Jump from the end of the body BB back to the loop header
pBodySuccBB->setTerminator( llr::Branch( pHeaderBB ) );
}
// Jump unconditionally from the pred block to the loop header.
pPrecBB->setTerminator( llr::Branch( pHeaderBB ) );
auto pSuccBB = p.cfg()->createBB();
auto breakLevel = p.breakableScopeLevels();
auto continueLevel = p.continuableScopeLevels();
// Go through all basic blocks, find all break and continue terminators
// for our scope level and replace them with branches respectively to
// the successor BB or to the loop header BB.
p.cfg()->ForEachBB( [&]( auto&& bb )
{
const auto& t = bb->terminator();
if( !t )
return;
if( const auto* pBreak = get_if< llr::Break >( &t->content() ) )
{
if( pBreak->level() == breakLevel )
bb->setTerminator( llr::Branch( pSuccBB ) );
return;
}
if( const auto* pCont = get_if< llr::Continue >( &t->content() ) )
{
if( pCont->level() == continueLevel )
bb->setTerminator( llr::Branch( pHeaderBB ) );
return;
}
} );
// Emit the conditional branch that will either run an iteration of the loop or exit to the succ bb.
pHeaderBB->setTerminator( llr::CondBranch(
get< Value >( converted ),
pBodyBB, pSuccBB ) );
p.cfg()->setCurrentBB( pSuccBB );
return true;
};
Rule r( handleWhile );
auto ruleVal = ToValue( move( r ) );
auto ruleTerm = ValueToIRExpr( ruleVal );
e.storeValue( AppendToVectorTerm( RootIdentity(), TSID( while ) ), ANYTERM( _ ), ruleTerm );
}
}
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