/****************************************************************
 *								*
 *	Copyright 2001, 2011 Fidelity Information Services, Inc	*
 *								*
 *	This source code contains the intellectual property	*
 *	of its copyright holder(s), and is made available	*
 *	under a license.  If you do not know the terms of	*
 *	the license, please stop and do not read further.	*
 *								*
 ****************************************************************/

#include "mdef.h"

#include "gtm_string.h"
#include "gtm_fcntl.h"
#include "gtm_unistd.h"
#include <errno.h>

#include "compiler.h"
#include "rtnhdr.h"
#include "obj_gen.h"
#include "cgp.h"
#include "mdq.h"
#include "hashtab_str.h"
#include "objlabel.h"
#include "stringpool.h"
#include "parse_file.h"
#include "gtmio.h"
#include "mmemory.h"
#include "obj_file.h"

GBLREF char		object_file_name[];
GBLREF short		object_name_len;
GBLREF int		object_file_des;
DEBUG_ONLY(GBLDEF int	obj_bytes_written;)

GBLREF boolean_t	run_time;
GBLREF int4		lits_text_size, lits_mval_size;
GBLREF unsigned char	*runtime_base;
GBLREF mliteral		literal_chain;
GBLREF char		source_file_name[];
GBLREF unsigned short	source_name_len;
GBLREF mident		routine_name;
GBLREF spdesc		stringpool;
GBLREF int4		linkage_size;
GBLREF uint4		lnkrel_cnt;	/* number of entries in linkage Psect to relocate */
GBLREF int4		sym_table_size;
GBLREF hash_table_str	*compsyms_hashtab;

static char			emit_buff[OBJ_EMIT_BUF_SIZE];	/* buffer for emit output */
static int			emit_buff_used;			/* number of chars in emit_buff */
static int			symcnt;
static struct rel_table		*link_rel, *link_rel_end;	/* Linkage relocation entries.  */
static struct linkage_entry	*linkage_first, *linkage_last;
static struct sym_table		*symbols;

void	emit_link_reference(int4 refoffset, mstr *name);

void	drop_object_file(void)
{
	int	rc;

        if (0 < object_file_des)
        {
		UNLINK(object_file_name);
		CLOSEFILE_RESET(object_file_des, rc);	/* resets "object_file_des" to FD_INVALID */
        }
}


/*
 *	emit_link_reference
 *
 *	Description: If not already defined, create relocation entry for
 *                   a linkage table entry to be resolved later.
 */
void	emit_link_reference(int4 refoffset, mstr *name)
{
	struct sym_table	*sym;
	struct rel_table	*newrel;

	sym = define_symbol(GTM_LINKAGE, name);
	assert(sym);
	if ((N_TEXT | N_EXT) != sym->n.n_type)
	{
		newrel = (struct rel_table *)mcalloc(SIZEOF(struct rel_table));
		newrel->next = (struct rel_table *)0;
		newrel->resolve = 0;
		newrel->r.r_address = refoffset;
		newrel->r.r_symbolnum = 0;
		if (NULL == link_rel)
			link_rel = newrel;
		else
			link_rel_end->next = newrel;
		link_rel_end = newrel;
		if (sym->resolve)
			newrel->resolve = sym->resolve;
		sym->resolve = newrel;
	}
}


/*
 *	emit_immed
 *
 *	Args:  buffer of executable code, and byte count to be output.
 */
void	emit_immed(char *source, uint4 size)
{
	short int 	write;
	error_def(ERR_STRINGOFLOW);

	if (run_time)
	{
		if (stringpool.free + size > stringpool.top)
			rts_error(VARLSTCNT(1) ERR_STRINGOFLOW);
		memcpy(stringpool.free, source, size);
		stringpool.free += size;
	} else
	{
		DEBUG_ONLY(obj_bytes_written += size);
		while (size > 0)
		{
			write = SIZEOF(emit_buff) - emit_buff_used;
			write = size < write ? size : write;
			memcpy(emit_buff + emit_buff_used, source, write);
			size -= write;
			source += write;
			emit_buff_used += write;
			if (0 != size)
				buff_emit();
		}
	}
}


/*
 *	buff_emit
 *
 *	Output partially or completely filled buffer
 */
void	buff_emit(void)
{
	int	stat;
	error_def(ERR_OBJFILERR);

	DOWRITERC(object_file_des, emit_buff, emit_buff_used, stat);
	if (0 != stat)
		rts_error(VARLSTCNT(5) ERR_OBJFILERR, 2, object_name_len, object_file_name, stat);
	emit_buff_used = 0;
}

/*
 * 	buff_flush
 *
 * 	Flush the contents of emit_buff to the file.
 */
void	buff_flush(void)
{
	if (emit_buff_used)
		buff_emit();
}

/*
 *	define_symbol
 *
 *	Args:  psect index, symbol name.
 *
 *	Description:  Buffers a definition of a global symbol with the
 *		given name in the given psect.
 */
struct sym_table *define_symbol(unsigned char psect, mstr *name)
{
	boolean_t		usehtab, added;
	int4			cmp;
	struct sym_table	*sym, *sym1, *newsym;
	stringkey		symkey;
	ht_ent_str		*syment;

	usehtab = (SYM_HASH_CUTOVER < symcnt);
	DEBUG_ONLY(syment = NULL);
	if (!usehtab)
	{	/* "Brute force" version of lookup for now */
		assert(NULL == compsyms_hashtab || NULL == compsyms_hashtab->base);
		sym = symbols;
		sym1 = NULL;
		while (sym)
		{
			if ((cmp = memvcmp(name->addr, (int)name->len, &sym->name[0], sym->name_len - 1)) <= 0)
				break;
			sym1 = sym;
			sym = sym->next;
		}
		if (!cmp && sym)
			return sym;
	} else
	{	/* Hashtable lookup -- Note use of hashtab_mname for this is somewhat overloading the usage since there
		   are compound symbols of the form "routine"."label" which can exceed the typical size of an mname but
		   since mnames are just addr/length pairs at the definition level, this works for us and is easier than
		   defining a new hashtable type identical to the mname hash in all but name.
		*/
		if (!compsyms_hashtab)
		{	/* Allocate if not allocated yet */
			compsyms_hashtab = (hash_table_str *)malloc(SIZEOF(hash_table_str));
			compsyms_hashtab->base = NULL;
		}
		if (!compsyms_hashtab->base)
		{	/* Need to initialize hash table and load it with the elements so far */
			init_hashtab_str(compsyms_hashtab, SYM_HASH_CUTOVER * 2, HASHTAB_NO_COMPACT, HASHTAB_NO_SPARE_TABLE);
			assert(compsyms_hashtab->base);
			for (sym = symbols; sym; sym = sym->next)
			{
				symkey.str.addr = (char *)&sym->name[0];
				symkey.str.len = sym->name_len - 1;
				COMPUTE_HASH_STR(&symkey);
				added = add_hashtab_str(compsyms_hashtab, &symkey, sym, &syment);
				assert(added);
				assert(syment->value);
				assert(syment->key.str.addr == (char *)&((struct sym_table *)syment->value)->name[0]);
			}
		}
		symkey.str = *name;	/* Copy of the key */
		COMPUTE_HASH_STR(&symkey);
		added = add_hashtab_str(compsyms_hashtab, &symkey, NULL, &syment);
		if (!added)
		{	/* Hash entry exists for this symbol */
			sym = (struct sym_table *)syment->value;
			assert(sym);
			assert(0 == memvcmp(name->addr, (int)name->len, &sym->name[0], sym->name_len - 1));
			return sym;
		}
	}

	/* Didn't find it in existing symbols; create new symbol.  */
	newsym = (struct sym_table *)mcalloc(SIZEOF(struct sym_table) + name->len);
	newsym->name_len = name->len + 1;
	memcpy(&newsym->name[0], name->addr, name->len);
	newsym->name[name->len] = 0;
	newsym->n.n_type = N_EXT;
	if (GTM_CODE == psect)
		newsym->n.n_type |= N_TEXT;	/* if symbol is in GTM_CODE, it is defined */
	else
		lnkrel_cnt++;	/* otherwise it's external (only one reference in linkage Psect) */
	newsym->resolve = 0;
	newsym->linkage_offset = -1;	/* don't assign linkage Psect offset unless it's used */
	if (!usehtab)
	{	/* Brute force -- add into the queue where the test failed (keeping sorted) */
		newsym->next = sym;
		if (sym1)
			sym1->next = newsym;
		else
			symbols = newsym;
	} else
	{	/* Hashtab usage -- add at beginning .. easiest since sorting doesn't matter for future lookups */
		newsym->next = symbols;
		symbols = newsym;
		assert(syment);
		syment->value = newsym;
	}
	++symcnt;
	sym_table_size += newsym->name_len;
	return newsym;
}


void	resolve_sym (void)
{
	uint4			symnum;
	struct sym_table	*sym;
	struct rel_table	*rel;

	for (sym = symbols, symnum = 0; sym; sym = sym->next, symnum++)
	{
		for (rel = sym->resolve; rel; rel = rel->resolve)
			rel->r.r_symbolnum = symnum;
	}
}


/* Output the relocation table for the linkage section */
void	output_relocation (void)
{
	struct rel_table	*rel;

	for (rel = link_rel; NULL != rel;  rel = rel->next)
		emit_immed((char *)&rel->r, SIZEOF(rel->r));
}


#ifdef DEBUG
/* Size that output_symbol() below will eventually generate -- used to verify validity of OUTPUT_SYMBOL_SIZE macro */
int	output_symbol_size(void)
{
	uint4			string_length;
	struct sym_table	*sym;

	string_length = SIZEOF(int4);
	sym = symbols;
	while (sym)
	{
		string_length += sym->name_len;
		sym = sym->next;
	}
	return string_length;
}
#endif


/* Symbol string table output. Consists of a series of null terminated
   strings in symbol number order.
*/
void	output_symbol(void)
{
	uint4			string_length;
	struct sym_table	*sym;

	string_length = SIZEOF(int4) + sym_table_size;
	assert(string_length == output_symbol_size());
	emit_immed((char *)&string_length, SIZEOF(string_length));
	sym = symbols;
	while (sym)
	{
		emit_immed((char *)&sym->name[0], sym->name_len);
		sym = sym->next;
	}
}


/*
 *	obj_init
 *
 *	Description:	Initialize symbol list, relocation information, linkage Psect list, linkage_size.
 */
void	obj_init(void)
{
	lnkrel_cnt = symcnt = 0;
	link_rel = link_rel_end = NULL;
	symbols = NULL;
	sym_table_size = 0;

	linkage_first = linkage_last = NULL;
	linkage_size = MIN_LINK_PSECT_SIZE;	/* minimum size of linkage Psect, assuming no references from generated code */

	return;
}


/*
 *	comp_linkages
 *
 *	Description: Define the symbols and relocation entries we will need to create
 *		     the linkage section when this module is linked in.
 */
void	comp_linkages(void)
{
	mstr			name;
	struct linkage_entry	*linkagep;

	for (linkagep = linkage_first; NULL != linkagep; linkagep = linkagep->next)
	{
		name.len = linkagep->symbol->name_len - 1;	/* don't count '\0' terminator */
		name.addr = (char *)&linkagep->symbol->name[0];
		emit_link_reference(linkagep->symbol->linkage_offset, &name);
	}

	return;
}


void	emit_literals(void)
{
	uint4		offset, padsize;
	mliteral	*p;

	/* emit the literal text pool which includes the source file path and routine name */
	offset = (uint4)(stringpool.free - stringpool.base);
	emit_immed((char *)stringpool.base, offset);
	padsize = (uint4)(PADLEN(offset, NATIVE_WSIZE)); /* comp_lits aligns the start of source path on NATIVE_WSIZE boundary.*/
	if (padsize)
	{
		emit_immed(PADCHARS, padsize);
		offset += padsize;
	}
	emit_immed(source_file_name, source_name_len);
	offset += source_name_len;
	padsize = (uint4)(PADLEN(offset, NATIVE_WSIZE)); /* comp_lits aligns the start of routine_name on NATIVE_WSIZE boundary.*/
	if (padsize)
	{
		emit_immed(PADCHARS, padsize);
		offset += padsize;
	}
	emit_immed(routine_name.addr, routine_name.len);
	offset += routine_name.len;
	padsize = (uint4)(PADLEN(offset, NATIVE_WSIZE)); /* comp_lits aligns the start of literal area on NATIVE_WSIZE boundary.*/
	if (padsize)
	{
		emit_immed(PADCHARS, padsize);
		offset += padsize;
	}
	assert(offset == lits_text_size);

	/* emit the literal mval list */
	offset = 0;
 	dqloop(&literal_chain, que, p)
	{
		assert(p->rt_addr == offset);
		MV_FORCE_NUMD(&p->v);
		if (p->v.str.len)
			p->v.str.addr = (char *)(p->v.str.addr - (char *)stringpool.base); /* Initial offset */
		else
			p->v.str.addr = NULL;
		p->v.fnpc_indx = (unsigned char)-1;
		emit_immed((char *)&p->v, SIZEOF(p->v));
		offset += SIZEOF(p->v);
	}
	assert (offset == lits_mval_size);
}


/*
 *	find_linkage
 *
 *	Argument:	the name of a global symbol
 *
 *	Description:	Returns the offset into the linkage Psect of a global symbol.
 */
int4	find_linkage(mstr* name)
{
	struct linkage_entry	*newlnk;
	struct sym_table	*sym;

	sym = define_symbol(GTM_LITERALS, name);

	if (-1 == sym->linkage_offset)
	{
		/* Add new linkage psect entry at end of list.  */
		sym ->linkage_offset = linkage_size;

		newlnk = (struct linkage_entry *)mcalloc(SIZEOF(struct linkage_entry));
		newlnk->symbol = sym;
		newlnk->next = NULL;
		if (NULL == linkage_first)
			linkage_first = newlnk;
		if (NULL != linkage_last)
			linkage_last->next = newlnk;
		linkage_last = newlnk;

		linkage_size += SIZEOF(lnk_tabent);
	}
	return sym->linkage_offset;
}


/*
 *	literal_offset
 *
 *	Argument:	Offset of literal in literal Psect.
 *
 *	Description:	Return offset to literal from literal Psect base register.
 */
int	literal_offset(UINTPTR_T offset)
{
	/* If we have no offset assigned yet, assume a really big offset. */
	if ((unsigned int)-1 == offset)
		offset = MAXPOSINT4;
	return (int)((run_time ? (offset - (UINTPTR_T)runtime_base) : offset));
}