CIfNode.cpp

/*
 *  CIfNode.cpp
 *  HyperCompiler
 *
 *  Created by Uli Kusterer on 19.05.07.
 *  Copyright 2007 M. Uli Kusterer. All rights reserved.
 *
 */

#include "CIfNode.h"
#include "CCodeBlock.h"
#include "CNodeTransformation.h"


namespace Carlson
{

/*
	- Push condition
	- Check condition & jump to else section if false -+
		- If section                                   |
	  +-- jump over else section                       |
	  | - else section    <----------------------------+
	  +-->
*/

void	CIfNode::GenerateCode( CCodeBlock* inBlock )
{
	// Push condition:
	mCondition->GenerateCode(inBlock);
	
	// Check condition, jump to Else start if FALSE:
	int32_t	compareInstructionOffset = (int32_t) inBlock->GetNextInstructionOffset();
	inBlock->GenerateJumpRelativeIfFalseInstruction( 0 );
	
	// Generate If section:
	CCodeBlockNode::GenerateCode( inBlock );
	
	// At end of If section, jump *over* Else section:
	int32_t	jumpOverElseInstructionOffset = (int32_t) inBlock->GetNextInstructionOffset();
	inBlock->GenerateJumpRelativeInstruction( 0 );
	
	// Retroactively fill in the address of the Else section in the if's jump instruction:
	int32_t		elseSectionStartOffset = (int32_t) inBlock->GetNextInstructionOffset();
	inBlock->SetJumpAddressOfInstructionAtIndex( compareInstructionOffset, elseSectionStartOffset -compareInstructionOffset );
	
	// Generate Else section:
	if( mElseBlock )
		mElseBlock->GenerateCode( inBlock );
	
	// Retroactively fill in the address of the end of the Else section in the jump instruction at the If's end:
	int32_t	elseSectionEndOffset = (int32_t) inBlock->GetNextInstructionOffset();
	inBlock->SetJumpAddressOfInstructionAtIndex( jumpOverElseInstructionOffset, elseSectionEndOffset -jumpOverElseInstructionOffset );
}


void	CIfNode::Simplify()
{
	CNode	*	originalNode = mCondition;
	originalNode->Simplify();	// Give subnodes a chance to apply transformations first. Might expose simpler sub-nodes we can then simplify.
	CNode* newNode = CNodeTransformationBase::Apply( originalNode );	// Returns either originalNode, or a totally new object, in which case we delete the old one.
	if( newNode != originalNode )
	{
		assert( dynamic_cast<CValueNode*>(newNode) != NULL );
		mCondition = (CValueNode*)newNode;
	}
	
	CCodeBlockNode::Simplify();
	
	if( mElseBlock )
	{
		originalNode = mElseBlock;
		originalNode->Simplify();	// Give subnodes a chance to apply transformations first. Might expose simpler sub-nodes we can then simplify.
		newNode = CNodeTransformationBase::Apply( originalNode );	// Returns either 'this', or an optimized copy. We get to keep one and delete the other.
		if( newNode != originalNode )
		{
			assert( dynamic_cast<CCodeBlockNode*>(newNode) != NULL );
			mElseBlock = (CCodeBlockNode*)newNode;
		}
	}
}


void	CIfNode::Visit( std::function<void(CNode*)> visitorBlock )
{
	mCondition->Visit(visitorBlock);
	
	if( mElseBlock )
		mElseBlock->Visit(visitorBlock);
	
	CCodeBlockNode::Visit( visitorBlock );
}


void	CIfNode::DebugPrint( std::ostream& destStream, size_t indentLevel )
{
	INDENT_PREPARE(indentLevel);
	
	destStream << indentChars << "If (" << std::endl;
	mCondition->DebugPrint( destStream, indentLevel );
	destStream << indentChars << ")" << std::endl;
	
	DebugPrintInner( destStream, indentLevel );
	
	if( mElseBlock )
	{
		destStream << indentChars << "else" << std::endl;
		
		mElseBlock->DebugPrintInner( destStream, indentLevel );
	}
}




}