/////////////////////////////////////////////////////////////// Loops
public void GenerateGenericLoop(IEnumerable <SyntaxNode> initializerNodes, IEnumerable <SyntaxNode> iteratorNodes, SyntaxNode conditionalNode, StatementSyntax loopScopeNode, FrontEndContext context)
{
// Always walk the initializer node statements first if they exists. The contents of this go before any loop block.
if (initializerNodes != null)
{
foreach (var initializerNode in initializerNodes)
{
WalkAndGetResult(initializerNode);
}
}
// A basic while looks like a header block that always jumps to a condition block.
// The condition block will choose to jump either to the loop block or to the merge point.
// The loop block will always branch to the continue target unless a break happens which
// will branch to the merge block (after the loop).
// The continue block will always jump back to the header block.
var headerBlock = mFrontEnd.CreateBlock("headerBlock");
var conditionBlock = mFrontEnd.CreateBlock("conditionBlock");
var loopTrueBlock = mFrontEnd.CreateBlock("loop-body");
var continueBlock = mFrontEnd.CreateBlock("continueBlock");
var mergeBlock = mFrontEnd.CreateBlock("after-loop");
// Always jump to the header block
mFrontEnd.CreateOp(context.mCurrentBlock, OpInstructionType.OpBranch, null, new List <IShaderIR> {
headerBlock
});
// The header always jumps to the conditional
context.mCurrentFunction.mBlocks.Add(headerBlock);
GenerateLoopHeaderBlock(headerBlock, conditionBlock, mergeBlock, continueBlock, context);
// The conditional will jump to either the loop body or the merge point (after the loop)
context.mCurrentFunction.mBlocks.Add(conditionBlock);
GenerateLoopConditionBlock(conditionalNode, conditionBlock, loopTrueBlock, mergeBlock, context);
// Walk all of the statements in the loop body and jump to either the merge or continue block
context.mCurrentFunction.mBlocks.Add(loopTrueBlock);
GenerateLoopStatements(loopScopeNode, loopTrueBlock, mergeBlock, continueBlock, context);
// The continue block always just jumps to the header block
context.mCurrentFunction.mBlocks.Add(continueBlock);
GenerateLoopContinueBlock(iteratorNodes, continueBlock, headerBlock, context);
// Afterwards the active block is always the merge point
context.mCurrentFunction.mBlocks.Add(mergeBlock);
context.mCurrentBlock = mergeBlock;
}
