// Copyright (C) 1994-1998 by Symantec
// Copyright (C) 2000-2009 by Digital Mars
// All Rights Reserved
// http://www.digitalmars.com
// Written by Walter Bright
/*
 * This source file is made available for personal use
 * only. The license is in /dmd/src/dmd/backendlicense.txt
 * or /dm/src/dmd/backendlicense.txt
 * For any other uses, please contact Digital Mars.
 */

// Support for NT exception handling

#include	<stdio.h>
#include	<string.h>
#include	<time.h>

#include	"cc.h"
#include	"el.h"
#include	"code.h"
#include	"oper.h"
#include	"global.h"
#include	"type.h"
#include	"dt.h"
#if SCPP
#include	"scope.h"
#include	"parser.h"
#include	"cpp.h"
#include	"exh.h"
#endif

#if !SPP && NTEXCEPTIONS

static char __file__[] = __FILE__;	/* for tassert.h		*/
#include	"tassert.h"

static symbol *s_table;
static symbol *s_context;
static char s_name_context_tag[] = "__nt_context";
static char s_name_context[] = "__context";
static char s_name_ecode[] = "__ecode";

static char text_nt[] =
    "struct __nt_context {"
	"int esp; int info; int prev; int handler; int stable; int sindex; int ebp;"
     "};\n";

// member stable is not used for MARS or C++

int nteh_EBPoffset_sindex()	{ return -4; }
int nteh_EBPoffset_prev()	{ return -nteh_contextsym_size() + 8; }
int nteh_EBPoffset_info()	{ return -nteh_contextsym_size() + 4; }
int nteh_EBPoffset_esp()	{ return -nteh_contextsym_size() + 0; }

int nteh_offset_sindex()	{ return MARS ? 16 : 20; }
int nteh_offset_sindex_seh()	{ return 20; }
int nteh_offset_info()		{ return 4; }

/***********************************
 */

unsigned char *nteh_context_string()
{
    if (config.flags2 & CFG2seh)
	return (unsigned char *)text_nt;
    else
	return NULL;
}

/*******************************
 * Get symbol for scope table for current function.
 * Returns:
 *	symbol of table
 */

STATIC symbol *nteh_scopetable()
{   symbol *s;
    type *t;

    if (!s_table)
    {
	t = type_alloc(TYint);
	s = symbol_generate(SCstatic,t);
	s->Sseg = UNKNOWN;
	symbol_keep(s);
	s_table = s;
    }
    return s_table;
}

/****************************
 * Generate and output scope table.
 */

void nteh_gentables()
{   symbol *s;
    int sz;			// size so far
    dt_t **pdt;
    unsigned fsize;		// target size of function pointer
    long spoff;
    block *b;
    int guarddim;
    int i;

    s = s_table;
    symbol_debug(s);
    fsize = 4;
    pdt = &s->Sdt;
    sz = 0;

#if MARS
    /*
	void*		pointer to start of function
	unsigned	offset of ESP from EBP
	unsigned	offset from start of function to return code
	{   int last_index;	// previous index
	    unsigned catchoffset;	// offset to catch block from symbol
	    void *finally;	// finally code to execute
	} guard[];
      catchoffset:
	unsigned ncatches;	// number of catch blocks
	{   void *type;		// symbol representing type
	    unsigned bpoffset;	// EBP offset of catch variable
	    void *handler;	// catch handler code
	} catch[];
     */

    sz = 0;

    // Address of start of function
    symbol_debug(funcsym_p);
    pdt = dtxoff(pdt,funcsym_p,0,TYnptr);
    sz += fsize;

    // Get offset of ESP from EBP
    spoff = cod3_spoff();
    pdt = dtnbytes(pdt,intsize,(char *)&spoff);
    sz += intsize;

    // Offset from start of function to return code
    pdt = dtnbytes(pdt,intsize,(char *)&retoffset);
    sz += intsize;

    // First, calculate starting catch offset
    guarddim = 0;				// max dimension of guard[]
    for (b = startblock; b; b = b->Bnext)
    {
	if (b->BC == BC_try && b->Bscope_index >= guarddim)
	    guarddim = b->Bscope_index + 1;
    }
    unsigned catchoffset = sz + guarddim * (3 * 4);

    // Generate guard[]
    i = 0;
    for (b = startblock; b; b = b->Bnext)
    {
	if (b->BC == BC_try)
	{   dt_t *dt;
	    block *bhandler;
	    int nsucc;

	    assert(b->Bscope_index >= i);
	    if (i < b->Bscope_index)
	    {
		pdt = dtnzeros(pdt, (b->Bscope_index - i) * (3 * 4));
		sz += (b->Bscope_index - i) * (3 * 4);
	    }
	    i = b->Bscope_index + 1;

	    nsucc = list_nitems(b->Bsucc);
	    pdt = dtdword(pdt,b->Blast_index);	// parent index

	    if (b->jcatchvar)				// if try-catch
	    {
		pdt = dtdword(pdt,catchoffset);
		pdt = dtdword(pdt,0);	// no finally handler

		catchoffset += 4 + (nsucc - 1) * (3 * 4);
	    }
	    else					// else try-finally
	    {
		assert(nsucc == 2);
		pdt = dtdword(pdt,0);		// no catch offset
		bhandler = list_block(list_next(b->Bsucc));
		assert(bhandler->BC == BC_finally);
		// To successor of BC_finally block
		bhandler = list_block(bhandler->Bsucc);
		pdt = dtcoff(pdt,bhandler->Boffset);	// finally handler address
	    }
	    sz += 4 + fsize * 2;
	}
    }

    // Generate catch[]
    for (b = startblock; b; b = b->Bnext)
    {
	if (b->BC == BC_try)
	{   block *bhandler;
	    int nsucc;

	    if (b->jcatchvar)				// if try-catch
	    {	list_t bl;

		nsucc = list_nitems(b->Bsucc);
		pdt = dtdword(pdt,nsucc - 1);		// # of catch blocks
		sz += 4;

		for (bl = list_next(b->Bsucc); bl; bl = list_next(bl))
		{
		    block *bcatch = list_block(bl);

		    pdt = dtxoff(pdt,bcatch->Bcatchtype,0,TYjhandle);

		    pdt = dtdword(pdt,cod3_bpoffset(b->jcatchvar));	// EBP offset

		    pdt = dtcoff(pdt,bcatch->Boffset);	// finally handler address

		    sz += 3 * 4;
		}
	    }
	}
    }
#else
    for (b = startblock; b; b = b->Bnext)
    {
	if (b->BC == BC_try)
	{   dt_t *dt;
	    block *bhandler;

	    pdt = dtdword(pdt,b->Blast_index);	// parent index

	    // If try-finally
	    if (list_nitems(b->Bsucc) == 2)
	    {
		pdt = dtdword(pdt,0);		// filter address
		bhandler = list_block(list_next(b->Bsucc));
		assert(bhandler->BC == BC_finally);
		// To successor of BC_finally block
		bhandler = list_block(bhandler->Bsucc);
	    }
	    else // try-except
	    {
		bhandler = list_block(list_next(b->Bsucc));
		assert(bhandler->BC == BC_filter);
		pdt = dtcoff(pdt,bhandler->Boffset);	// filter address
		bhandler = list_block(list_next(list_next(b->Bsucc)));
		assert(bhandler->BC == BC_except);
	    }
	    pdt = dtcoff(pdt,bhandler->Boffset);	// handler address
	    sz += 4 + fsize * 2;
	}
    }
#endif
    assert(sz != 0);

    outdata(s);			// output the scope table
#if MARS
    nteh_framehandler(s);
#endif
    s_table = NULL;
}

/**************************
 * Declare frame variables.
 */

void nteh_declarvars(Blockx *bx)
{   symbol *s;

#if MARS
    if (!(bx->funcsym->Sfunc->Fflags3 & Fnteh))	// if haven't already done it
    {	bx->funcsym->Sfunc->Fflags3 |= Fnteh;
	s = symbol_name(s_name_context,SCbprel,tsint);
	s->Soffset = -5 * 4;		// -6 * 4 for C __try, __except, __finally
	s->Sflags |= SFLfree | SFLnodebug;
	type_setty(&s->Stype,mTYvolatile | TYint);
	symbol_add(s);
	bx->context = s;
    }
#else
    if (!(funcsym_p->Sfunc->Fflags3 & Fnteh))	// if haven't already done it
    {	funcsym_p->Sfunc->Fflags3 |= Fnteh;
	if (!s_context)
	    s_context = scope_search(s_name_context_tag,CPP ? SCTglobal : SCTglobaltag);
	symbol_debug(s_context);

	s = symbol_name(s_name_context,SCbprel,s_context->Stype);
	s->Soffset = -6 * 4;		// -5 * 4 for C++
	s->Sflags |= SFLfree;
	symbol_add(s);
	type_setty(&s->Stype,mTYvolatile | TYstruct);

	s = symbol_name(s_name_ecode,SCauto,type_alloc(mTYvolatile | TYint));
	s->Sflags |= SFLfree;
	symbol_add(s);
    }
#endif
}

/**************************************
 * Generate elem that sets the context index into the scope table.
 */

#if MARS
elem *nteh_setScopeTableIndex(Blockx *blx, int scope_index)
{
    elem *e;
    Symbol *s;

    s = blx->context;
    symbol_debug(s);
    e = el_var(s);
    e->EV.sp.Voffset = nteh_offset_sindex();
    return el_bin(OPeq, TYint, e, el_long(TYint, scope_index));
}
#endif


/**********************************
 * Return pointer to context symbol.
 */

symbol *nteh_contextsym()
{   SYMIDX si;
    symbol *sp;

    for (si = 0; 1; si++)
    {	assert(si < globsym.top);
	sp = globsym.tab[si];
	symbol_debug(sp);
	if (strcmp(sp->Sident,s_name_context) == 0)
	    return sp;
    }
}

/**********************************
 * Return size of context symbol on stack.
 */

unsigned nteh_contextsym_size()
{   int sz;

    if (usednteh & NTEH_try)
    {
#if MARS
	sz = 5 * 4;
#elif SCPP
	sz = 6 * 4;
#else
	assert(0);
#endif
	assert(usedalloca != 1);
    }
    else if (usednteh & NTEHcpp)
    {	sz = 5 * 4;			// C++ context record
	assert(usedalloca != 1);
    }
    else if (usednteh & NTEHpassthru)
    {	sz = 1 * 4;
    }
    else
	sz = 0;				// no context record
    return sz;
}

/**********************************
 * Return pointer to ecode symbol.
 */

symbol *nteh_ecodesym()
{   SYMIDX si;
    symbol *sp;

    for (si = 0; 1; si++)
    {	assert(si < globsym.top);
	sp = globsym.tab[si];
	symbol_debug(sp);
	if (strcmp(sp->Sident,s_name_ecode) == 0)
	    return sp;
    }
}

/*********************************
 * Mark EH variables as used so that they don't get optimized away.
 */

void nteh_usevars()
{
#if SCPP
    // Turn off SFLdead and SFLunambig in Sflags
    nteh_contextsym()->Sflags &= ~(SFLdead | SFLunambig);
    nteh_contextsym()->Sflags |= SFLread;
    nteh_ecodesym()->Sflags   &= ~(SFLdead | SFLunambig);
    nteh_ecodesym()->Sflags   |= SFLread;
#else
    // Turn off SFLdead and SFLunambig in Sflags
    nteh_contextsym()->Sflags &= ~SFLdead;
    nteh_contextsym()->Sflags |= SFLread;
#endif
}

/*********************************
 * Generate NT exception handling function prolog.
 */

code *nteh_prolog()
{
    code cs;
    code *c1;
    code *c;

    if (usednteh & NTEHpassthru)
    {
	/* An sindex value of -2 is a magic value that tells the
	 * stack unwinder to skip this frame.
	 */
	assert(config.exe & (EX_LINUX | EX_LINUX64 | EX_OSX | EX_OSX64 | EX_FREEBSD | EX_FREEBSD64 | EX_SOLARIS | EX_SOLARIS64));
	cs.Iop = 0x68;
	cs.Iflags = 0;
	cs.Ijty = 0;
	cs.IFL2 = FLconst;
	cs.IEV2.Vint = -2;
	return gen(CNIL,&cs);			// PUSH -2
    }

    /* Generate instance of struct __nt_context on stack frame:
	[  ]					// previous ebp already there
	push	-1				// sindex
	mov	EDX,FS:__except_list
	push	offset FLAT:scope_table		// stable (not for MARS or C++)
	push	offset FLAT:__except_handler3	// handler
	push	EDX				// prev
	mov	FS:__except_list,ESP
	sub	ESP,8				// info, esp for __except support
     */

//    useregs(mAX);			// What is this for?

    cs.Iop = 0x68;
    cs.Iflags = 0;
    cs.Ijty = 0;
    cs.IFL2 = FLconst;
    cs.IEV2.Vint = -1;
    c1 = gen(CNIL,&cs);			// PUSH -1

    if (usednteh & NTEHcpp || MARS)
    {
	// PUSH &framehandler
	cs.IFL2 = FLframehandler;
#if MARS
	nteh_scopetable();
#endif
    }
    else
    {
	// Do stable
	cs.Iflags |= CFoff;
	cs.IFL2 = FLextern;
	cs.IEVsym2 = nteh_scopetable();
	cs.IEVoffset2 = 0;
	c1 = gen(c1,&cs);			// PUSH &scope_table

	cs.IFL2 = FLextern;
	cs.IEVsym2 = rtlsym[RTLSYM_EXCEPT_HANDLER3];
	makeitextern(rtlsym[RTLSYM_EXCEPT_HANDLER3]);
    }
    c = gen(NULL,&cs);				// PUSH &__except_handler3

    if (config.exe == EX_NT)
    {
	makeitextern(rtlsym[RTLSYM_EXCEPT_LIST]);
    #if 0
	cs.Iop = 0xFF;
	cs.Irm = modregrm(0,6,BPRM);
	cs.Iflags = CFfs;
	cs.Ijty = 0;
	cs.IFL1 = FLextern;
	cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
	cs.IEVoffset1 = 0;
	gen(c,&cs);				// PUSH FS:__except_list
    #else
	useregs(mDX);
	cs.Iop = 0x8B;
	cs.Irm = modregrm(0,DX,BPRM);
	cs.Iflags = CFfs;
	cs.Ijty = 0;
	cs.IFL1 = FLextern;
	cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
	cs.IEVoffset1 = 0;
	gen(c1,&cs);				// MOV EDX,FS:__except_list

	gen1(c,0x50 + DX);			// PUSH EDX
    #endif
	cs.Iop = 0x89;
	NEWREG(cs.Irm,SP);
	gen(c,&cs);				// MOV FS:__except_list,ESP
    }

    c = genc2(c,0x81,modregrm(3,5,SP),8);	// SUB ESP,8

    return cat(c1,c);
}

/*********************************
 * Generate NT exception handling function epilog.
 */

code *nteh_epilog()
{
    if (!(config.flags2 & CFG2seh))
	return NULL;

    /* Generate:
	mov	ECX,__context[EBP].prev
	mov	FS:__except_list,ECX
     */
    code cs;
    code *c;
    unsigned reg;

#if MARS
    reg = CX;
#else
    reg = (tybasic(funcsym_p->Stype->Tnext->Tty) == TYvoid) ? AX : CX;
#endif
    useregs(mask[reg]);

    cs.Iop = 0x8B;
    cs.Irm = modregrm(2,reg,BPRM);
    cs.Iflags = 0;
    cs.Ijty = 0;
    cs.IFL1 = FLconst;
    // EBP offset of __context.prev
    cs.IEV1.Vint = nteh_EBPoffset_prev();
    c = gen(CNIL,&cs);

    cs.Iop = 0x89;
    cs.Irm = modregrm(0,reg,BPRM);
    cs.Iflags |= CFfs;
    cs.IFL1 = FLextern;
    cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
    cs.IEVoffset1 = 0;
    return gen(c,&cs);
}

/**************************
 * Set/Reset ESP from context.
 */

code *nteh_setsp(int op)
{   code cs;

    cs.Iop = op;
    cs.Irm = modregrm(2,SP,BPRM);
    cs.Iflags = 0;
    cs.Ijty = 0;
    cs.IFL1 = FLconst;
    // EBP offset of __context.esp
    cs.IEV1.Vint = nteh_EBPoffset_esp();
    return gen(CNIL,&cs);		// MOV ESP,__context[EBP].esp
}

/****************************
 * Put out prolog for BC_filter block.
 */

code *nteh_filter(block *b)
{   code *c;
    code cs;

    assert(b->BC == BC_filter);
    c = CNIL;
    if (b->Bflags & BFLehcode)		// if referenced __ecode
    {
	/* Generate:
		mov	EAX,__context[EBP].info
		mov	EAX,[EAX]
		mov	EAX,[EAX]
		mov	__ecode[EBP],EAX
	 */

	c = getregs(mAX);

	cs.Iop = 0x8B;
	cs.Irm = modregrm(2,AX,BPRM);
	cs.Iflags = 0;
	cs.Ijty = 0;
	cs.IFL1 = FLconst;
	// EBP offset of __context.info
	cs.IEV1.Vint = nteh_EBPoffset_info();
	c = gen(c,&cs);			// MOV EAX,__context[EBP].info
	cs.Irm = modregrm(0,AX,0);
	gen(c,&cs);			// MOV EAX,[EAX]
	gen(c,&cs);			// MOV EAX,[EAX]
	cs.Iop = 0x89;
	cs.Irm = modregrm(2,AX,BPRM);
	cs.IFL1 = FLauto;
	cs.IEVsym1 = nteh_ecodesym();
	cs.IEVoffset1 = 0;
	gen(c,&cs);			// MOV __ecode[EBP],EAX
    }
    return c;
}

/*******************************
 * Generate C++ or Jupiter frame handler.
 */

void nteh_framehandler(symbol *scopetable)
{   code *c;

    // Generate:
    //	MOV	EAX,&scope_table
    //	JMP	__cpp_framehandler

    if (scopetable)
    {
	symbol_debug(scopetable);
	c = gencs(NULL,0xB8+AX,0,FLextern,scopetable);	// MOV EAX,&scope_table
	gencs(c,0xE9,0,FLfunc,rtlsym[RTLSYM_CPP_HANDLER]);	// JMP __cpp_framehandler

	pinholeopt(c,NULL);
	codout(c);
	code_free(c);
    }
}

/*********************************
 * Generate code to set scope index.
 */

code *nteh_gensindex(int sindex)
{   code *c;

    if (!(config.flags2 & CFG2seh))
	return NULL;

    // Generate:
    //	MOV	-4[EBP],sindex

    c = genc(NULL,0xC7,modregrm(1,0,BP),FLconst,(targ_uns)nteh_EBPoffset_sindex(),FLconst,sindex);	// 7 bytes long
    c->Iflags |= CFvolatile;
#ifdef DEBUG
    //assert(GENSINDEXSIZE == calccodsize(c));
#endif
    return c;
}

/*********************************
 * Generate code for setjmp().
 */

code *cdsetjmp(elem *e,regm_t *pretregs)
{   code cs;
    code *c;
    regm_t retregs;
    unsigned stackpushsave;
    unsigned flag;

    c = NULL;
    stackpushsave = stackpush;
#if SCPP
    if (CPP && (funcsym_p->Sfunc->Fflags3 & Fcppeh || usednteh & NTEHcpp))
    {
	/*  If in C++ try block
	    If the frame that is calling setjmp has a try,catch block then
	    the call to setjmp3 is as follows:
	      __setjmp3(environment,3,__cpp_longjmp_unwind,trylevel,funcdata);

	    __cpp_longjmp_unwind is a routine in the RTL. This is a 
	    stdcall routine that will deal with unwinding for CPP Frames. 
	    trylevel is the value that gets incremented at each catch, 
	    constructor invocation.
	    funcdata is the same value that you put into EAX prior to 
	    cppframehandler getting called.
	 */
	symbol *s;

	s = except_gensym();
	if (!s)
	    goto L1;

	c = gencs(c,0x68,0,FLextern,s);			// PUSH &scope_table
	stackpush += 4;
	genadjesp(c,4);

	c = genc1(c,0xFF,modregrm(1,6,BP),FLconst,(targ_uns)-4);
						// PUSH trylevel
	stackpush += 4;
	genadjesp(c,4);

	cs.Iop = 0x68;
	cs.Iflags = CFoff;
	cs.Ijty = 0;
	cs.IFL2 = FLextern;
	cs.IEVsym2 = rtlsym[RTLSYM_CPP_LONGJMP];
	cs.IEVoffset2 = 0;
	c = gen(c,&cs);				// PUSH &_cpp_longjmp_unwind
	stackpush += 4;
	genadjesp(c,4);

	flag = 3;
    }
    else
#endif
    if (funcsym_p->Sfunc->Fflags3 & Fnteh)
    {
	/*  If in NT SEH try block
	    If the frame that is calling setjmp has a try, except block
	    then the call to setjmp3 is as follows:
	      __setjmp3(environment,2,__seh_longjmp_unwind,trylevel);
	    __seth_longjmp_unwind is supplied by the RTL and is a stdcall
	    function. It is the name that MSOFT uses, we should 
	    probably use the same one.
	    trylevel is the value that you increment at each try and 
	    decrement at the close of the try.  This corresponds to the
	    index field of the ehrec.
	 */
	int sindex_off;

	sindex_off = 20;		// offset of __context.sindex
	cs.Iop = 0xFF;
	cs.Irm = modregrm(2,6,BPRM);
	cs.Iflags = 0;
	cs.Ijty = 0;
	cs.IFL1 = FLbprel;
	cs.IEVsym1 = nteh_contextsym();
	cs.IEVoffset1 = sindex_off;
	c = gen(c,&cs);			// PUSH scope_index
	stackpush += 4;
	genadjesp(c,4);

	cs.Iop = 0x68;
	cs.Iflags = CFoff;
	cs.Ijty = 0;
	cs.IFL2 = FLextern;
	cs.IEVsym2 = rtlsym[RTLSYM_LONGJMP];
	cs.IEVoffset2 = 0;
	c = gen(c,&cs);			// PUSH &_seh_longjmp_unwind
	stackpush += 4;
	genadjesp(c,4);

	flag = 2;
    }
    else
    {
	/*  If the frame calling setjmp has neither a try..except, nor a 
	    try..catch, then call setjmp3 as follows:
	    _setjmp3(environment,0)
	 */
    L1:
	flag = 0;
    }

    cs.Iop = 0x68;
    cs.Iflags = 0;
    cs.Ijty = 0;
    cs.IFL2 = FLconst;
    cs.IEV2.Vint = flag;
    c = gen(c,&cs);			// PUSH flag
    stackpush += 4;
    genadjesp(c,4);

    c = cat(c,params(e->E1,REGSIZE));

    c = cat(c,getregs(~rtlsym[RTLSYM_SETJMP3]->Sregsaved & (ALLREGS | mES)));
    gencs(c,0xE8,0,FLfunc,rtlsym[RTLSYM_SETJMP3]);	// CALL __setjmp3

    c = genc2(c,0x81,modregrm(3,0,SP),stackpush - stackpushsave);	// ADD ESP,8
    genadjesp(c,-(stackpush - stackpushsave));

    stackpush = stackpushsave;
    retregs = regmask(e->Ety, TYnfunc);
    return cat(c,fixresult(e,retregs,pretregs));
}

/****************************************
 * Call _local_unwind(), which means call the __finally blocks until
 * index is reached.
 */

code *nteh_unwind(regm_t retregs,unsigned index)
{   code *c;
    code cs;
    code *cs1;
    code *cs2;
    int i;
    regm_t desregs;
    int reg;
    int local_unwind;

    // Shouldn't this always be CX?
#if SCPP
    reg = AX;
#else
    reg = CX;
#endif

#if MARS
    local_unwind = RTLSYM_D_LOCAL_UNWIND2;
#else
    local_unwind = RTLSYM_LOCAL_UNWIND2;
#endif
    desregs = (~rtlsym[local_unwind]->Sregsaved & (ALLREGS)) | mask[reg];
    gensaverestore(retregs & desregs,&cs1,&cs2);

    c = getregs(desregs);

    cs.Iop = 0x8D;
    cs.Irm = modregrm(2,reg,BPRM);
    cs.Iflags = 0;
    cs.Ijty = 0;
    cs.IFL1 = FLconst;
    // EBP offset of __context.prev
    cs.IEV1.Vint = nteh_EBPoffset_prev();
    c = gen(c,&cs);				// LEA  ECX,contextsym

    genc2(c,0x68,0,index);			// PUSH index
    gen1(c,0x50 + reg);				// PUSH ECX

#if MARS
    //gencs(c,0xB8+AX,0,FLextern,nteh_scopetable());	// MOV EAX,&scope_table
    gencs(c,0x68,0,FLextern,nteh_scopetable());		// PUSH &scope_table

    gencs(c,0xE8,0,FLfunc,rtlsym[local_unwind]);	// CALL __d_local_unwind2()
    genc2(c,0x81,modregrm(3,0,SP),12);			// ADD ESP,12
#else
    gencs(c,0xE8,0,FLfunc,rtlsym[local_unwind]);	// CALL __local_unwind2()
    genc2(c,0x81,modregrm(3,0,SP),8);			// ADD ESP,8
#endif

    c = cat4(cs1,c,cs2,NULL);
    return c;
}

/****************************************
 * Call _local_unwind(), which means call the __finally blocks until
 * index is reached.
 */

#if 0 // Replaced with inline calls to __finally blocks

code *linux_unwind(regm_t retregs,unsigned index)
{   code *c;
    code cs;
    code *cs1;
    code *cs2;
    int i;
    regm_t desregs;
    int reg;
    int local_unwind;

    // Shouldn't this always be CX?
#if SCPP
    reg = AX;
#else
    reg = CX;
#endif

#if MARS
    local_unwind = RTLSYM_D_LOCAL_UNWIND2;
#else
    local_unwind = RTLSYM_LOCAL_UNWIND2;
#endif
    desregs = (~rtlsym[local_unwind]->Sregsaved & (ALLREGS)) | mask[reg];
    gensaverestore(retregs & desregs,&cs1,&cs2);

    c = getregs(desregs);
    c = genc2(c,0x68,0,index);			// PUSH index

#if MARS
//    gencs(c,0x68,0,FLextern,nteh_scopetable());		// PUSH &scope_table

    gencs(c,0xE8,0,FLfunc,rtlsym[local_unwind]);	// CALL __d_local_unwind2()
    genc2(c,0x81,modregrm(3,0,SP),4);			// ADD ESP,12
#else
    gencs(c,0xE8,0,FLfunc,rtlsym[local_unwind]);	// CALL __local_unwind2()
    genc2(c,0x81,modregrm(3,0,SP),8);			// ADD ESP,8
#endif

    c = cat4(cs1,c,cs2,NULL);
    return c;
}

#endif

/*************************************************
 * Set monitor, hook monitor exception handler.
 */

#if MARS

code *nteh_monitor_prolog(Symbol *shandle)
{
    /*
     *	PUSH	handle
     *	PUSH	offset _d_monitor_handler
     *	PUSH	FS:__except_list
     *	MOV	FS:__except_list,ESP
     *	CALL	_d_monitor_prolog
     */
    code *c1 = NULL;
    code *c;
    code cs;
    Symbol *s;
    regm_t desregs;

    assert(config.flags2 & CFG2seh);	// BUG: figure out how to implement for other EX's

    if (shandle->Sclass == SCfastpar)
    {	assert(shandle->Spreg != DX);
	c = gen1(NULL,0x50 + shandle->Spreg);	// PUSH shandle
    }
    else
    {
	// PUSH shandle
#if 0
	c = genc1(NULL,0xFF,modregrm(2,6,4),FLconst,4 * (1 + needframe) + shandle->Soffset + localsize);
	c->Isib = modregrm(0,4,SP);
#else
	useregs(mCX);
	c = genc1(NULL,0x8B,modregrm(2,CX,4),FLconst,4 * (1 + needframe) + shandle->Soffset + localsize);
	c->Isib = modregrm(0,4,SP);
	gen1(c,0x50 + CX);			// PUSH ECX
#endif
    }

    s = rtlsym[RTLSYM_MONITOR_HANDLER];
    c = gencs(c,0x68,0,FLextern,s);		// PUSH offset _d_monitor_handler
    makeitextern(s);

#if 0
    cs.Iop = 0xFF;
    cs.Irm = modregrm(0,6,BPRM);
    cs.Iflags = CFfs;
    cs.Ijty = 0;
    cs.IFL1 = FLextern;
    cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
    cs.IEVoffset1 = 0;
    gen(c,&cs);				// PUSH FS:__except_list
#else
    useregs(mDX);
    cs.Iop = 0x8B;
    cs.Irm = modregrm(0,DX,BPRM);
    cs.Iflags = CFfs;
    cs.Ijty = 0;
    cs.IFL1 = FLextern;
    cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
    cs.IEVoffset1 = 0;
    c1 = gen(c1,&cs);			// MOV EDX,FS:__except_list

    gen1(c,0x50 + DX);			// PUSH EDX
#endif

    s = rtlsym[RTLSYM_MONITOR_PROLOG];
    desregs = ~s->Sregsaved & ALLREGS;
    c = cat(c,getregs(desregs));
    c = gencs(c,0xE8,0,FLfunc,s);	// CALL _d_monitor_prolog

    cs.Iop = 0x89;
    NEWREG(cs.Irm,SP);
    gen(c,&cs);				// MOV FS:__except_list,ESP

    return cat(c1,c);
}

#endif

/*************************************************
 * Release monitor, unhook monitor exception handler.
 * Input:
 *	retregs		registers to not destroy
 */

#if MARS

code *nteh_monitor_epilog(regm_t retregs)
{
    /*
     *	CALL	_d_monitor_epilog
     *	POP	FS:__except_list
     */
    code cs;
    code *c;
    code *cs1;
    code *cs2;
    code *cpop;
    int i;
    regm_t desregs;
    Symbol *s;

    assert(config.flags2 & CFG2seh);	// BUG: figure out how to implement for other EX's

    s = rtlsym[RTLSYM_MONITOR_EPILOG];
    //desregs = ~s->Sregsaved & ALLREGS;
    desregs = 0;
    gensaverestore(retregs & desregs,&cs1,&cs2);

    c = getregs(desregs);
    c = gencs(c,0xE8,0,FLfunc,s);		// CALL __d_monitor_epilog

    cs.Iop = 0x8F;
    cs.Irm = modregrm(0,0,BPRM);
    cs.Iflags = CFfs;
    cs.Ijty = 0;
    cs.IFL1 = FLextern;
    cs.IEVsym1 = rtlsym[RTLSYM_EXCEPT_LIST];
    cs.IEVoffset1 = 0;
    cpop = gen(NULL,&cs);			// POP FS:__except_list

    c = cat4(cs1,c,cs2,cpop);
    return c;
}

#endif

#endif
