c2asm.cpp

将C语言转换成汇编语言

		//It sometimes Happens that even -ve INDICES also points 
		//to some array element causing PROBLEMS
		if(k<0) break;	
		index=args_identifier[k].binding;
	}
	return tot_len;
}

int calc_local_offset()
{
	int counter=0;
	//Chk For LOCAL's which are BINDED to LATEST "func_index"
	for(unsigned int i=0;i<syn_identifier.size();i++)
		if(syn_identifier[i].binding==func_index)
		{
		counter+=syn_identifier[i].datatype==0 ? 2 : 4;
		syn_identifier[i].offset=counter;
		}
return counter;
}

void syntax_box()
{
	//Doing Initializations
	syn_index=0;
	input=tokens[syn_index];
	scopecount=0;
	scopestack.push(scopecount);
	dump.index=-10;
	dump.datatype=-10;
	dump.whichtable=-10;
	
	program();
	
	//Check whether we've got our End Of Marker
	//Yes,End Marker has Arrived,ACCEPT INPUT PROGRAM!
	if(input.clas=="error")
	{
	error<<syn_index+1<<'\t'<<input.clas<<'\t'<<input.index<<'\t'<<scopestack.top()<<endl;
	error.close();
	//cout<<"\nParser Succeeded";
	//cout<<"\nSee \"parser_log.txt\" For Details";
	}
	//No,End Marker hasn't Arrived,REJECT INPUT PROGRAM!
	else
	{
	error<<syn_index+1<<'\t'<<input.clas<<'\t'<<input.index<<'\t'<<scopestack.top()<<endl;
	error.close();
    cout<<"\nParser Failed";
	cout<<"\nParser has parsed "<< syn_index+1 <<" Tokens\n";
	cout<<"See \"parser_log.txt\" For Details\n";
	}
	
	//If u wanna See IDENTIFERs LIST with ALL details,Remove Comments from the following Lines
	/*
	cout<<"\n\nIDENTIFIERS";
	cout<<endl<<" name "<<" "<<"datatype"
		<<" "<<"scope"<<" "<<"binding"<<" "<<"f_or_not"
		<<" "<<"type"<<" "<<"offset ";
	for(unsigned int j=0;j<syn_identifier.size();j++)
	cout<<endl<<j<<" "<<syn_identifier[j].name<<'\t'
		  <<syn_identifier[j].datatype
    <<'\t'<<syn_identifier[j].scope
	<<'\t'<<syn_identifier[j].binding
	<<'\t'<<syn_identifier[j].func_or_not
	<<'\t'<<syn_identifier[j].type
	<<'\t'<<syn_identifier[j].offset
	<<'\t'<<syn_identifier[j].xtra;
	*/

	//If u wanna See What Paramters are Binded to Which Fucntion,Remove Comments from the 
	//following Lines
	/*
	cout<<"\n\nBINDINGS";
	for(j=0;j<args_identifier.size();j++)
	cout<<endl<<j<<" "<<args_identifier[j].name<<'\t'
		  <<args_identifier[j].datatype
    <<'\t'<<args_identifier[j].scope
	<<'\t'<<args_identifier[j].binding
	<<'\t'<<args_identifier[j].func_or_not
	<<'\t'<<args_identifier[j].type
	<<'\t'<<args_identifier[j].offset
	<<'\t'<<args_identifier[j].xtra;
	*/
	
	
}

void program()
{
	if(input.clas=="dt")
	{
		int type=input.index;
		advanc();
		
		if(input.clas=="id")
		{
			int index=input.index;
			settype(index,type);
			advanc();
		}
		else reject();
		
		data_or_function(type);
		program();
	}
	else if(input.clas=="void")
	{
		advanc();
		function_or_main();
	}
	else reject();
}

void data_or_function(int type)
{
	if(input.clas=="comma")
	{
		advanc();
		if(input.clas=="id")
		{
			int index=input.index;
            settype(index,type);			
			advanc();
		}
		else reject();
		data_or_function(type);
	}
	else if(input.clas=="semicolon")
		advanc();
	else if(input.clas=="parenthesis_open")
	{
		/*Since This Fucntion Shld've a RETURN statement in it's 
		body,Therefore Setting "isreturn=false",To LET IT BE TURNED
		to TRUE by a STATEMENT in Fucntion's body*/
		isreturn=false;

		advanc();
		argument_list();
		if(input.clas=="parenthesis_close")
			advanc();
		else reject();

		function_body();
	}
	else reject();
}

void function_or_main()
{
	if(input.clas=="main")
	{
		// Set FLAG to true,Since it's main STARTING
		main_func=true;

		advanc();
		if(input.clas=="parenthesis_open")
			advanc();
		else reject();
		
		if(input.clas=="void")
			advanc();
		else reject();

		if(input.clas=="parenthesis_close")
			advanc();
		else reject();

		function_body();
	}
	else if(input.clas=="id")
	{
		settype(input.index,22);
		advanc();

		if(input.clas=="parenthesis_open")
			advanc();
		else reject();

		argument_list();

		if(input.clas=="parenthesis_close")
			advanc();
		else reject();

		function_body();
		program();
	}
	else reject();
}

void function_body()
{
	int start_atom,end_atom,total;
	start_atom=end_atom=total=-10;

	if(input.clas=="braces_open")
	{
		//
		//Marking Begining Of Function
		//
		
		//Is it a main() function?
		if(main_func==true)
		{
		expr temp;
		temp.index=-1;	    //-1 For main() OR func_index For others
		temp.datatype=1;    //1 Shows Starting,0 Shows Ending
		temp.whichtable=-10; 

		setatom(34,temp,dump,dump);
		}
		//It's an ORDINARY function
		else
		{
		expr temp;
		temp.index=func_index;	    //-1 For main() OR func_index For others
		temp.datatype=1;    //1 Shows Starting,0 Shows Ending
		temp.whichtable=-10;

		setatom(34,temp,dump,dump);
		start_atom=atoms.size()-1;	//Storing Index Of Starting ATOM
		}

		//Update scope_or_binding.
		scopecount++;
		scopestack.push(scopecount);

			advanc();
			
			variable_declarations();
			statements();
			
			if(input.clas=="braces_close")
			{
				if((scopestack.size()-1)>0)
							scopestack.pop();
				else
					reject();
			advanc();
			}
			else
			reject();

		//
		//Marking Ending Of Function
		//
		
		//Is it a main() function?
		if(main_func==true)
		{
		expr temp;
		temp.index=-1;	    //-1 For main() OR func_index For others
		temp.datatype=0;    //1 Shows Starting,0 Shows Ending
		temp.whichtable=-10;
		
		setatom(34,temp,dump,dump);
		}
		//It's an ORDINARY function
		else
		{
		expr temp;
		temp.index=func_index;	    //-1 For main() OR func_index For others
		temp.datatype=0;    //1 Shows Starting,0 Shows Ending
		temp.whichtable=-10;
				
		setatom(34,temp,dump,dump);
		end_atom=atoms.size()-1;	//Storing Index Of Ending ATOM
		}
		
		//Setting LOCAL VARIABLES+TEMPoRARIES' OFFSETS.
		if(func_index!=-10)
		{
			total=calc_local_offset();
			//Now,Saving The TOTAL LENGTH of OFFSETS into the Starting 
			//and Ending PROC_MARKER ATOMS Of this Particular Fucntion
			atoms[start_atom].arg1.whichtable=total;
			atoms[end_atom].arg1.whichtable=total;
		}


		/*If this Fucntion has to return something,ASSURING that it
		has done this ATLEAST one time!*/
		if(func_index!=-10)
		{
			if(isreturn!=true&& syn_identifier[func_index].datatype!=22/*Shldn't Be void*/)
			{
				cout<<endl<<"Fucntion named "<< syn_identifier[func_index].name 
				<<" Shld return "<< syn_identifier[func_index].datatype <<endl;
				reject();
			}
		}
	
		main_func=false;	//Main Fucntion Ended
		func_index=-10;	//De-Registering Fucntion if it was local
		isreturn=false;	//Re-Setting the Return Flag
	}
	else
		reject();
}

void variable_declarations()
{
	if(input.clas=="dt")
	{
		int type=input.index;
			advanc();
			
			if(input.clas=="id")
			{
				int index=input.index;
				settype(index,type);
				advanc();
			}
			else reject();
			
			variable_list(type);

			if(input.clas=="semicolon")
				advanc();
			else reject();

			variable_declarations();
	}
	else if(input.clas=="id" || input.clas=="braces_open" || input.clas=="while" ||
		input.clas=="for" || input.clas=="do" || input.clas=="return" || 
		input.clas=="if" || input.clas=="square_open" || input.clas=="braces_close" )
	{
	
	}
	else reject();
}

void variable_list(int type)
{
	if(input.clas=="comma")
	{
		advanc();
		
		if(input.clas=="id")
		{
			int index=input.index;
			settype(index,type);
			advanc();
		}
		else reject();

		variable_list(type);
	}
	else if(input.clas=="semicolon")
	{ 
	
	}
	else reject();
}

void argument_list()
{
	if(input.clas=="void")
	{
		ident.name="void";
		ident.datatype=22;
		ident.scope=-10;
		ident.binding=syn_identifier.size()-1;
		ident.func_or_not=false;
		ident.type=3;	//For Parameters 3!.
		ident.offset=-10;	//We'll calculate it LATER
		ident.xtra=-10;

		args_identifier.push_back(ident);

		//Since we got argument list for our recently entered identifier,
		//therefore we need to recognize that as a FUNCTION NAME EXPLICITLY.
		//Updating IDENTIFIER SYMBOL TABLE
		int ind=syn_identifier.size()-1;
		ident=syn_identifier[ind];
		ident.func_or_not=true;
		syn_identifier[ind]=ident;

		//Registering This Fucntion's Start
		func_index=ind;

		advanc();
	}
    else if(input.clas=="dt")
	{
		int type=input.index;
		advanc();
		if(input.clas=="id")
		{
			int index=input.index;
            settype_args(index,type);
			advanc();
		}
		else reject();
		argument();

		//Since we got argument list for our recently entered identifier,
		//therefore we need to recognize that as a FUNCTION NAME EXPLICITLY.
		//Updating IDENTIFIER SYMBOL TABLE
		int ind=syn_identifier.size()-1;
		ident=syn_identifier[ind];
		ident.func_or_not=true;
		syn_identifier[ind]=ident;

		//Registering This Fucntion's Start
		func_index=ind;

		//Caculating Fucntion Parameter's Offsets
		int ret=calc_param_offset();

		//Storing the Total SIZE of PARAMETERS
		syn_identifier[ind].xtra=ret;
	}
	else reject();
}

void argument()
{
	if(input.clas=="comma")
	{
		int type;
		advanc();
		
		if(input.clas=="dt")
		{
			type=input.index;
			advanc();
		}
		else reject();

		if(input.clas=="id")
		{
			int index=input.index;
			settype_args(index,type);
			advanc();
		}
		else reject();

		argument();
	}
	else if(input.clas=="parenthesis_close")
	{
	
	}
	else reject();
}

void compound_statement()
{
	if(input.clas=="braces_open")
	{
		advanc();
		
		statements();
		
		if(input.clas=="braces_close")
			advanc();
		else reject();
	}
	else reject();
}

void statements()
{
	if(input.clas=="id"||input.clas=="braces_open"||input.clas=="while"||
		input.clas=="for"||input.clas=="do"||input.clas=="return"||
		input.clas=="if"||input.clas=="square_open")
	{
		statement();
		statements();
	}
	else if(input.clas=="braces_close")
	{
	
	}
	else reject();
}

void statement()
{
	if(input.clas=="id")
	{
		long ind=chk_ident(long(input.index));
		if(ind==-10)
		{
			cout<<"\nFailed in <Statement>-->id=<right_hand_side>;";
			cout<<"\nVariable Not Found ";
			reject();
		}
		expr t;
		t.index=ind;
		t.whichtable=table;
		if(table==0)
		t.datatype=syn_identifier[ind].datatype;
		else if(table==1)
		t.datatype=args_identifier[ind].datatype;

		advanc();

		if(input.clas=="assignop")
			advanc();
		else reject();
		
		expr r;
		right_hand_side(r);

		if(input.clas=="semicolon")
		advanc();
		else reject();
		
		if(chk_types(t,r)==true)
		{
		setatom(26,r,dump,t);
		}
		else
		{
				cout<<"\nType of id != <right_hand_side>";
				reject();
		}
	}
	else if(input.clas=="braces_open")
	{
		compound_statement();
	}
	else if(input.clas=="while")
	{
		expr temp;
		
		int start=newlabel();
		int end=newlabel();

		temp.datatype=25;
		temp.index=start;
		temp.whichtable=4;	// For Labels;

		setatom(25,dump,dump,temp);

		advanc();
		
		if(input.clas=="parenthesis_open")
			advanc();
		else reject();
		expr k;
		expression(k);
	
		if(input.clas=="parenthesis_close")
			advanc();
		else reject();

		temp.datatype=25;
		temp.index=end;
		temp.whichtable=4;

		expr temp1;
		temp1.datatype=0;
		temp1.index=-10;
		temp1.whichtable=-10;

		setatom(27,k,temp1,temp);

		statement();

		temp.datatype=25;
		temp.index=start;
		temp.whichtable=4;
		setatom(28,dump,dump,temp);

		temp.datatype=25;
		temp.index=end;
		temp.whichtable=4;

		setatom(25,dump,dump,temp);
	}
	else if(input.clas=="for")
	{
		int start=newlabel();
		int end=newlabel();
		int t_1=newlabel();