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cgcod.c
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cgcod.c
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// Copyright (C) 1985-1998 by Symantec
// Copyright (C) 2000-2013 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 backendlicense.txt
* For any other uses, please contact Digital Mars.
*/
#if !SPP
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#if __sun || _MSC_VER
#include <alloca.h>
#endif
#include "cc.h"
#include "el.h"
#include "oper.h"
#include "code.h"
#include "global.h"
#include "type.h"
#include "exh.h"
#include "xmm.h"
#include "dwarf.h"
static char __file__[] = __FILE__; /* for tassert.h */
#include "tassert.h"
STATIC void resetEcomsub(elem *e);
STATIC code * loadcse(elem *,unsigned,regm_t);
STATIC void blcodgen(block *);
STATIC void cgcod_eh();
STATIC code * cse_save(regm_t ms);
STATIC code * comsub(elem *,regm_t *);
bool floatreg; // !=0 if floating register is required
int hasframe; // !=0 if this function has a stack frame
targ_size_t spoff;
targ_size_t Foff; // BP offset of floating register
targ_size_t CSoff; // offset of common sub expressions
targ_size_t NDPoff; // offset of saved 8087 registers
targ_size_t pushoff; // offset of saved registers
bool pushoffuse; // using pushoff
int BPoff; // offset from BP
int EBPtoESP; // add to EBP offset to get ESP offset
LocalSection Para; // section of function parameters
LocalSection Auto; // section of automatics and registers
LocalSection Fast; // section of fastpar
LocalSection EEStack; // offset of SCstack variables from ESP
LocalSection Alloca; // data for alloca() temporary
REGSAVE regsave;
CGstate cgstate; // state of code generator
regm_t BYTEREGS = BYTEREGS_INIT;
regm_t ALLREGS = ALLREGS_INIT;
/************************************
* # of bytes that SP is beyond BP.
*/
unsigned stackpush;
int stackchanged; /* set to !=0 if any use of the stack
other than accessing parameters. Used
to see if we can address parameters
with ESP rather than EBP.
*/
int refparam; // !=0 if we referenced any parameters
int reflocal; // !=0 if we referenced any locals
bool anyiasm; // !=0 if any inline assembler
char calledafunc; // !=0 if we called a function
char needframe; // if TRUE, then we will need the frame
// pointer (BP for the 8088)
char gotref; // !=0 if the GOTsym was referenced
unsigned usednteh; // if !=0, then used NT exception handling
/* Register contents */
con_t regcon;
int pass; // PASSxxxx
static symbol *retsym; // set to symbol that should be placed in
// register AX
/****************************
* Register masks.
*/
regm_t msavereg; // Mask of registers that we would like to save.
// they are temporaries (set by scodelem())
regm_t mfuncreg; // Mask of registers preserved by a function
#if __DMC__
extern "C" {
// make sure it isn't merged with ALLREGS
regm_t __cdecl allregs; // ALLREGS optionally including mBP
}
#else
regm_t allregs; // ALLREGS optionally including mBP
#endif
int dfoidx; /* which block we are in */
struct CSE *csextab = NULL; /* CSE table (allocated for each function) */
size_t cstop; // # of entries in CSE table (csextab[])
size_t csmax; // amount of space in csextab[]
targ_size_t funcoffset; // offset of start of function
targ_size_t prolog_allocoffset; // offset past adj of stack allocation
targ_size_t startoffset; // size of function entry code
targ_size_t retoffset; /* offset from start of func to ret code */
targ_size_t retsize; /* size of function return */
static regm_t lastretregs,last2retregs,last3retregs,last4retregs,last5retregs;
/*********************************
* Generate code for a function.
* Note at the end of this routine mfuncreg will contain the mask
* of registers not affected by the function. Some minor optimization
* possibilities are here...
*/
void codgen()
{
bool flag;
#if SCPP
block *btry;
#endif
// Register usage. If a bit is on, the corresponding register is live
// in that basic block.
//printf("codgen('%s')\n",funcsym_p->Sident);
cgreg_init();
csmax = 64;
csextab = (struct CSE *) util_calloc(sizeof(struct CSE),csmax);
tym_t functy = tybasic(funcsym_p->ty());
cod3_initregs();
allregs = ALLREGS;
pass = PASSinit;
Alloca.init();
anyiasm = 0;
tryagain:
#ifdef DEBUG
if (debugr)
printf("------------------ PASS%s -----------------\n",
(pass == PASSinit) ? "init" : ((pass == PASSreg) ? "reg" : "final"));
#endif
lastretregs = last2retregs = last3retregs = last4retregs = last5retregs = 0;
// if no parameters, assume we don't need a stack frame
needframe = 0;
gotref = 0;
stackchanged = 0;
stackpush = 0;
refparam = 0;
calledafunc = 0;
retsym = NULL;
cgstate.stackclean = 1;
cgstate.funcarg.init();
cgstate.funcargtos = ~0;
regsave.reset();
#if TX86
memset(_8087elems,0,sizeof(_8087elems));
#endif
usednteh = 0;
#if (MARS) && TARGET_WINDOS
if (funcsym_p->Sfunc->Fflags3 & Fjmonitor)
usednteh |= NTEHjmonitor;
#else
if (CPP)
{
if (config.exe == EX_WIN32 &&
(funcsym_p->Stype->Tflags & TFemptyexc || funcsym_p->Stype->Texcspec))
usednteh |= NTEHexcspec;
except_reset();
}
#endif
// Set on a trial basis, turning it off if anything might throw
funcsym_p->Sfunc->Fflags3 |= Fnothrow;
floatreg = FALSE;
#if TX86
assert(stackused == 0); /* nobody in 8087 stack */
#endif
cstop = 0; /* no entries in table yet */
memset(®con,0,sizeof(regcon));
regcon.cse.mval = regcon.cse.mops = 0; // no common subs yet
msavereg = 0;
unsigned nretblocks = 0;
mfuncreg = fregsaved; // so we can see which are used
// (bit is cleared each time
// we use one)
for (block* b = startblock; b; b = b->Bnext)
{ memset(&b->Bregcon,0,sizeof(b->Bregcon)); // Clear out values in registers
if (b->Belem)
resetEcomsub(b->Belem); // reset all the Ecomsubs
if (b->BC == BCasm)
anyiasm = 1; // we have inline assembler
if (b->BC == BCret || b->BC == BCretexp)
nretblocks++;
}
if (!config.fulltypes || (config.flags4 & CFG4optimized))
{
regm_t noparams = 0;
for (int i = 0; i < globsym.top; i++)
{
Symbol *s = globsym.tab[i];
s->Sflags &= ~SFLread;
switch (s->Sclass)
{ case SCfastpar:
case SCshadowreg:
regcon.params |= s->Spregm();
case SCparameter:
if (s->Sfl == FLreg)
noparams |= s->Sregm;
break;
}
}
regcon.params &= ~noparams;
}
if (config.flags4 & CFG4optimized)
{
if (nretblocks == 0 && // if no return blocks in function
!(funcsym_p->ty() & mTYnaked)) // naked functions may have hidden veys of returning
funcsym_p->Sflags |= SFLexit; // mark function as never returning
assert(dfo);
cgreg_reset();
for (dfoidx = 0; dfoidx < dfotop; dfoidx++)
{ regcon.used = msavereg | regcon.cse.mval; // registers already in use
block* b = dfo[dfoidx];
blcodgen(b); // gen code in depth-first order
//printf("b->Bregcon.used = %s\n", regm_str(b->Bregcon.used));
cgreg_used(dfoidx, b->Bregcon.used); // gather register used information
}
}
else
{ pass = PASSfinal;
for (block* b = startblock; b; b = b->Bnext)
blcodgen(b); // generate the code for each block
}
regcon.immed.mval = 0;
assert(!regcon.cse.mops); // should have all been used
// See which variables we can put into registers
if (pass != PASSfinal &&
!anyiasm) // possible LEA or LES opcodes
{
allregs |= cod3_useBP(); // see if we can use EBP
// If pic code, but EBX was never needed
if (!(allregs & mask[PICREG]) && !gotref)
{ allregs |= mask[PICREG]; // EBX can now be used
cgreg_assign(retsym);
pass = PASSreg;
}
else if (cgreg_assign(retsym)) // if we found some registers
pass = PASSreg;
else
pass = PASSfinal;
for (block* b = startblock; b; b = b->Bnext)
{ code_free(b->Bcode);
b->Bcode = NULL;
}
goto tryagain;
}
cgreg_term();
#if SCPP
if (CPP)
cgcod_eh();
#endif
stackoffsets(1); // compute addresses of stack variables
cod5_prol_epi(); // see where to place prolog/epilog
// Get rid of unused cse temporaries
while (cstop != 0 && (csextab[cstop - 1].flags & CSEload) == 0)
cstop--;
if (configv.addlinenumbers)
objmod->linnum(funcsym_p->Sfunc->Fstartline,Coffset);
// Otherwise, jmp's to startblock will execute the prolog again
assert(!startblock->Bpred);
code* cprolog = prolog(); // gen function start code
if (cprolog)
pinholeopt(cprolog,NULL); // optimize
funcoffset = Coffset;
targ_size_t coffset = Coffset;
if (eecontext.EEelem)
genEEcode();
for (block* b = startblock; b; b = b->Bnext)
{
// We couldn't do this before because localsize was unknown
switch (b->BC)
{ case BCret:
if (configv.addlinenumbers && b->Bsrcpos.Slinnum && !(funcsym_p->ty() & mTYnaked))
cgen_linnum(&b->Bcode,b->Bsrcpos);
case BCretexp:
epilog(b);
break;
default:
if (b->Bflags & BFLepilog)
epilog(b);
break;
}
assignaddr(b); // assign addresses
pinholeopt(b->Bcode,b); // do pinhole optimization
if (b->Bflags & BFLprolog) // do function prolog
{
startoffset = coffset + calcblksize(cprolog) - funcoffset;
b->Bcode = cat(cprolog,b->Bcode);
}
cgsched_block(b);
b->Bsize = calcblksize(b->Bcode); // calculate block size
if (b->Balign)
{ targ_size_t u = b->Balign - 1;
coffset = (coffset + u) & ~u;
}
b->Boffset = coffset; /* offset of this block */
coffset += b->Bsize; /* offset of following block */
}
#ifdef DEBUG
debugw && printf("code addr complete\n");
#endif
// Do jump optimization
do
{ flag = FALSE;
for (block* b = startblock; b; b = b->Bnext)
{ if (b->Bflags & BFLjmpoptdone) /* if no more jmp opts for this blk */
continue;
int i = branch(b,0); // see if jmp => jmp short
if (i) // if any bytes saved
{ targ_size_t offset;
b->Bsize -= i;
offset = b->Boffset + b->Bsize;
for (block* bn = b->Bnext; bn; bn = bn->Bnext)
{
if (bn->Balign)
{ targ_size_t u = bn->Balign - 1;
offset = (offset + u) & ~u;
}
bn->Boffset = offset;
offset += bn->Bsize;
}
coffset = offset;
flag = TRUE;
}
}
if (!I16 && !(config.flags4 & CFG4optimized))
break; // use the long conditional jmps
} while (flag); // loop till no more bytes saved
#ifdef DEBUG
debugw && printf("code jump optimization complete\n");
#endif
#if MARS
if (usednteh & NTEH_try)
{
// Do this before code is emitted because we patch some instructions
nteh_filltables();
}
#endif
// Compute starting offset for switch tables
targ_size_t swoffset;
if (config.flags & CFGromable)
swoffset = coffset;
else if (config.objfmt == OBJ_ELF || config.objfmt == OBJ_MACH)
swoffset = CDoffset;
else
swoffset = Doffset;
swoffset = align(0,swoffset);
// Emit the generated code
if (eecontext.EEcompile == 1)
{
codout(eecontext.EEcode);
code_free(eecontext.EEcode);
#if SCPP
el_free(eecontext.EEelem);
#endif
}
else
{
for (block* b = startblock; b; b = b->Bnext)
{
if (b->BC == BCjmptab || b->BC == BCswitch)
{
swoffset = align(0,swoffset);
b->Btableoffset = swoffset; /* offset of sw tab */
swoffset += b->Btablesize;
}
jmpaddr(b->Bcode); /* assign jump addresses */
#ifdef DEBUG
if (debugc)
{ printf("Boffset = x%lx, Bsize = x%lx, Coffset = x%lx\n",
(long)b->Boffset,(long)b->Bsize,(long)Coffset);
if (b->Bcode)
printf( "First opcode of block is: %0x\n", b->Bcode->Iop );
}
#endif
if (b->Balign)
{ unsigned u = b->Balign;
unsigned nalign = (u - (unsigned)Coffset) & (u - 1);
cod3_align_bytes(nalign);
}
assert(b->Boffset == Coffset);
#if SCPP
if (CPP &&
!(config.exe == EX_WIN32))
{
//printf("b = %p, index = %d\n",b,b->Bindex);
//except_index_set(b->Bindex);
if (btry != b->Btry)
{
btry = b->Btry;
except_pair_setoffset(b,Coffset - funcoffset);
}
if (b->BC == BCtry)
{
btry = b;
except_pair_setoffset(b,Coffset - funcoffset);
}
}
#endif
codout(b->Bcode); // output code
}
if (coffset != Coffset)
{
#ifdef DEBUG
printf("coffset = %ld, Coffset = %ld\n",(long)coffset,(long)Coffset);
#endif
assert(0);
}
funcsym_p->Ssize = Coffset - funcoffset; // size of function
#if NTEXCEPTIONS || MARS
#if (SCPP && NTEXCEPTIONS)
if (usednteh & NTEHcpp)
#elif MARS
if (usednteh & NTEH_try)
#endif
{ assert(!(config.flags & CFGromable));
//printf("framehandleroffset = x%x, coffset = x%x\n",framehandleroffset,coffset);
objmod->reftocodeseg(cseg,framehandleroffset,coffset);
}
#endif
// Write out switch tables
flag = FALSE; // TRUE if last active block was a ret
for (block* b = startblock; b; b = b->Bnext)
{
switch (b->BC)
{ case BCjmptab: /* if jump table */
outjmptab(b); /* write out jump table */
goto Ldefault;
case BCswitch:
outswitab(b); /* write out switch table */
goto Ldefault;
case BCret:
case BCretexp:
/* Compute offset to return code from start of function */
retoffset = b->Boffset + b->Bsize - retsize - funcoffset;
#if MARS
/* Add 3 bytes to retoffset in case we have an exception
* handler. THIS PROBABLY NEEDS TO BE IN ANOTHER SPOT BUT
* IT FIXES THE PROBLEM HERE AS WELL.
*/
if (usednteh & NTEH_try)
retoffset += 3;
#endif
flag = TRUE;
break;
default:
Ldefault:
retoffset = b->Boffset + b->Bsize - funcoffset;
break;
}
}
if (configv.addlinenumbers && !(funcsym_p->ty() & mTYnaked))
/* put line number at end of function on the
start of the last instruction
*/
/* Instead, try offset to cleanup code */
objmod->linnum(funcsym_p->Sfunc->Fendline,funcoffset + retoffset);
#if TARGET_WINDOS && MARS
if (config.exe == EX_WIN64)
win64_pdata(funcsym_p);
#endif
#if MARS
if (usednteh & NTEH_try)
{
// Do this before code is emitted because we patch some instructions
nteh_gentables();
}
if (usednteh & EHtry && // saw BCtry or BC_try (test EHcleanup too?)
config.ehmethod == EH_DM)
{
except_gentables();
}
if (config.ehmethod == EH_DWARF)
{
funcsym_p->Sfunc->Fstartblock = startblock;
dwarf_except_gentables(funcsym_p, startoffset, retoffset);
funcsym_p->Sfunc->Fstartblock = NULL;
}
#endif
#if SCPP
#if NTEXCEPTIONS
// Write out frame handler
if (usednteh & NTEHcpp)
nteh_framehandler(except_gentables());
else
#endif
{
#if NTEXCEPTIONS
if (usednteh & NTEH_try)
nteh_gentables();
else
#endif
{
if (CPP)
except_gentables();
}
;
}
#endif
for (block* b = startblock; b; b = b->Bnext)
{
code_free(b->Bcode);
b->Bcode = NULL;
}
}
// Mask of regs saved
// BUG: do interrupt functions save BP?
funcsym_p->Sregsaved = (functy == TYifunc) ? mBP : (mfuncreg | fregsaved);
util_free(csextab);
csextab = NULL;
#if TX86
#ifdef DEBUG
if (stackused != 0)
printf("stackused = %d\n",stackused);
#endif
assert(stackused == 0); /* nobody in 8087 stack */
/* Clean up ndp save array */
mem_free(NDP::save);
NDP::save = NULL;
NDP::savetop = 0;
NDP::savemax = 0;
#endif
}
/*********************************************
* Align sections on the stack.
* base negative offset of section from frame pointer
* alignment alignment to use
* bias difference between where frame pointer points and the STACKALIGNed
* part of the stack
* Returns:
* base revised downward so it is aligned
*/
targ_size_t alignsection(targ_size_t base, unsigned alignment, int bias)
{
assert((int)base <= 0);
if (alignment > STACKALIGN)
alignment = STACKALIGN;
if (alignment)
{
int sz = -base + bias;
assert(sz >= 0);
sz &= (alignment - 1);
if (sz)
base -= alignment - sz;
}
return base;
}
/*******************************
* Generate code for a function start.
* Input:
* Coffset address of start of code
* Auto.alignment
* Output:
* Coffset adjusted for size of code generated
* EBPtoESP
* hasframe
* BPoff
*/
code *prolog()
{
bool enter;
regm_t namedargs = 0;
//printf("cod3.prolog() %s, needframe = %d, Auto.alignment = %d\n", funcsym_p->Sident, needframe, Auto.alignment);
debugx(debugw && printf("funcstart()\n"));
regcon.immed.mval = 0; /* no values in registers yet */
EBPtoESP = -REGSIZE;
hasframe = 0;
bool pushds = false;
BPoff = 0;
code *c = CNIL;
bool pushalloc = false;
tym_t tyf = funcsym_p->ty();
tym_t tym = tybasic(tyf);
unsigned farfunc = tyfarfunc(tym);
// Special Intel 64 bit ABI prolog setup for variadic functions
symbol *sv64 = NULL; // set to __va_argsave
if (I64 && variadic(funcsym_p->Stype))
{
/* The Intel 64 bit ABI scheme.
* abi_sysV_amd64.pdf
* Load arguments passed in registers into the varargs save area
* so they can be accessed by va_arg().
*/
/* Look for __va_argsave
*/
for (SYMIDX si = 0; si < globsym.top; si++)
{ symbol *s = globsym.tab[si];
if (s->Sident[0] == '_' && strcmp(s->Sident, "__va_argsave") == 0)
{
if (!(s->Sflags & SFLdead))
sv64 = s;
break;
}
}
}
if (config.flags & CFGalwaysframe ||
funcsym_p->Sfunc->Fflags3 & Ffakeeh ||
/* The exception stack unwinding mechanism relies on the EBP chain being intact,
* so need frame if function can possibly throw
*/
!(config.exe == EX_WIN32) && !(funcsym_p->Sfunc->Fflags3 & Fnothrow) ||
sv64
)
needframe = 1;
Lagain:
spoff = 0;
char guessneedframe = needframe;
int cfa_offset = 0;
// if (needframe && config.exe & (EX_LINUX | EX_FREEBSD | EX_SOLARIS) && !(usednteh & ~NTEHjmonitor))
// usednteh |= NTEHpassthru;
/* Compute BP offsets for variables on stack.
* The organization is:
* Para.size parameters
* -------- stack is aligned to STACKALIGN
* seg of return addr (if far function)
* IP of return addr
* BP-> caller's BP
* DS (if Windows prolog/epilog)
* exception handling context symbol
* Fast.size fastpar
* Auto.size autos and regs
* regsave.off any saved registers
* Foff floating register
* Alloca.size alloca temporary
* CSoff common subs
* NDPoff any 8087 saved registers
* monitor context record
* any saved registers
*/
if (tym == TYifunc)
Para.size = 26; // how is this number derived?
else
Para.size = (farfunc ? 3 : 2) * REGSIZE;
/* The real reason for the FAST section is because the implementation of contracts
* requires a consistent stack frame location for the 'this' pointer. But if varying
* stuff in Auto.offset causes different alignment for that section, the entire block can
* shift around, causing a crash in the contracts.
* Fortunately, the 'this' is always an SCfastpar, so we put the fastpar's in their
* own FAST section, which is never aligned at a size bigger than REGSIZE, and so
* its alignment never shifts around.
* But more work needs to be done, see Bugzilla 9200. Really, each section should be aligned
* individually rather than as a group.
*/
Fast.size = 0;
#if NTEXCEPTIONS == 2
Fast.size -= nteh_contextsym_size();
#if MARS
#if TARGET_WINDOS
if (funcsym_p->Sfunc->Fflags3 & Ffakeeh && nteh_contextsym_size() == 0)
Fast.size -= 5 * 4;
#endif
#endif
#endif
/* Despite what the comment above says, aligning Fast section to size greater
* than REGSIZE does not break contract implementation. Fast.offset and
* Fast.alignment must be the same for the overriding and
* the overriden function, since they have the same parameters. Fast.size
* must be the same because otherwise, contract inheritance wouldn't work
* even if we didn't align Fast section to size greater than REGSIZE. Therefore,
* the only way aligning the section could cause problems with contract
* inheritance is if bias (declared below) differed for the overriden
* and the overriding function.
*
* Bias depends on Para.size and needframe. The value of Para.size depends on
* whether the function is an interrupt handler and whether it is a farfunc.
* DMD does not have _interrupt attribute and D does not make a distinction
* between near and far functions, so Para.size should always be 2 * REGSIZE
* for D.
*
* The value of needframe depends on a global setting that is only set
* during backend's initialization and on function flag Ffakeeh. On Windows,
* that flag is always set for virtual functions, for which contracts are
* defined and on other platforms, it is never set. Because of that
* the value of neadframe should always be the same for the overriden
* and the overriding function, and so bias should be the same too.
*/
int bias = Para.size + (needframe ? 0 : REGSIZE);
if (Fast.alignment < REGSIZE)
Fast.alignment = REGSIZE;
Fast.size = alignsection(Fast.size - Fast.offset, Fast.alignment, bias);
if (Auto.alignment < REGSIZE)
Auto.alignment = REGSIZE; // necessary because localsize must be REGSIZE aligned
Auto.size = alignsection(Fast.size - Auto.offset, Auto.alignment, bias);
regsave.off = alignsection(Auto.size - regsave.top, regsave.alignment, bias);
if (floatreg)
{
unsigned floatregsize = config.fpxmmregs || I32 ? 16 : DOUBLESIZE;
Foff = alignsection(regsave.off - floatregsize, STACKALIGN, bias);
}
else
Foff = regsave.off;
Alloca.alignment = REGSIZE;
Alloca.offset = alignsection(Foff - Alloca.size, Alloca.alignment, bias);
CSoff = alignsection(Alloca.offset - cstop * REGSIZE, REGSIZE, bias);
NDPoff = alignsection(CSoff - NDP::savetop * tysize[TYldouble], REGSIZE, bias);
regm_t topush = fregsaved & ~mfuncreg; // mask of registers that need saving
pushoffuse = false;
pushoff = NDPoff;
/* We don't keep track of all the pushes and pops in a function. Hence,
* using POP REG to restore registers in the epilog doesn't work, because the Dwarf unwinder
* won't be setting ESP correctly. With pushoffuse, the registers are restored
* from EBP, which is kept track of properly.
*/
if ((config.flags4 & CFG4speed || config.ehmethod == EH_DWARF) && (I32 || I64))
{
/* Instead of pushing the registers onto the stack one by one,
* allocate space in the stack frame and copy/restore them there.
*/
int xmmtopush = numbitsset(topush & XMMREGS); // XMM regs take 16 bytes
int gptopush = numbitsset(topush) - xmmtopush; // general purpose registers to save
if (NDPoff || xmmtopush || cgstate.funcarg.size)
{
pushoff = alignsection(pushoff - (gptopush * REGSIZE + xmmtopush * 16),
xmmtopush ? STACKALIGN : REGSIZE, bias);
pushoffuse = true; // tell others we're using this strategy
}
}
//printf("Fast.size = x%x, Auto.size = x%x\n", (int)Fast.size, (int)Auto.size);
cgstate.funcarg.alignment = STACKALIGN;
cgstate.funcarg.offset = alignsection(pushoff - cgstate.funcarg.size, cgstate.funcarg.alignment, bias);
localsize = -cgstate.funcarg.offset;
//printf("Alloca.offset = x%llx, cstop = x%llx, CSoff = x%llx, NDPoff = x%llx, localsize = x%llx\n",
//(long long)Alloca.offset, (long long)cstop, (long long)CSoff, (long long)NDPoff, (long long)localsize);
assert((targ_ptrdiff_t)localsize >= 0);
// Keep the stack aligned by 8 for any subsequent function calls
if (!I16 && calledafunc &&
(STACKALIGN == 16 || config.flags4 & CFG4stackalign))
{
int npush = numbitsset(topush); // number of registers that need saving
npush += numbitsset(topush & XMMREGS); // XMM regs take 16 bytes, so count them twice
if (pushoffuse)
npush = 0;
//printf("npush = %d Para.size = x%x needframe = %d localsize = x%x\n",
//npush, Para.size, needframe, localsize);
int sz = Para.size + (needframe ? 0 : -REGSIZE) + localsize + npush * REGSIZE;
if (STACKALIGN == 16)
{
if (sz & (8|4))
localsize += STACKALIGN - (sz & (8|4));
}
else if (sz & 4)
localsize += 4;
}
cgstate.funcarg.offset = -localsize;
//printf("Foff x%02x Auto.size x%02x NDPoff x%02x CSoff x%02x Para.size x%02x localsize x%02x\n",
//(int)Foff,(int)Auto.size,(int)NDPoff,(int)CSoff,(int)Para.size,(int)localsize);
unsigned xlocalsize = localsize; // amount to subtract from ESP to make room for locals
if (tyf & mTYnaked) // if no prolog/epilog for function
{
hasframe = 1;
return NULL;
}
if (tym == TYifunc)
{
c = cat(c, prolog_ifunc(&tyf));
hasframe = 1;
goto Lcont;
}
/* Determine if we need BP set up */
if (config.flags & CFGalwaysframe)
needframe = 1;
else
{
if (localsize)
{
if (I16 ||
!(config.flags4 & CFG4speed) ||
config.target_cpu < TARGET_Pentium ||
farfunc ||
config.flags & CFGstack ||
xlocalsize >= 0x1000 ||
(usednteh & ~NTEHjmonitor) ||
anyiasm ||
Alloca.size
)
needframe = 1;
}
if (refparam && (anyiasm || I16))
needframe = 1;
}
if (needframe)
{ assert(mfuncreg & mBP); // shouldn't have used mBP
if (!guessneedframe) // if guessed wrong
goto Lagain;
}
if (I16 && config.wflags & WFwindows && farfunc)
{
c = cat(c, prolog_16bit_windows_farfunc(&tyf, &pushds));
enter = false; /* don't use ENTER instruction */
hasframe = 1; /* we have a stack frame */
}
else if (needframe) // if variables or parameters
{
c = cat(c, prolog_frame(farfunc, &xlocalsize, &enter, &cfa_offset));
hasframe = 1;
}
/* Subtract from stack pointer the size of the local stack frame
*/
{
code *cstackadj = CNIL;
if (config.flags & CFGstack) // if stack overflow check
{
cstackadj = prolog_frameadj(tyf, xlocalsize, enter, &pushalloc);
if (Alloca.size)
cstackadj = cat(cstackadj, prolog_setupalloca());
}
else if (needframe) /* if variables or parameters */
{
if (xlocalsize) /* if any stack offset */
{
cstackadj = prolog_frameadj(tyf, xlocalsize, enter, &pushalloc);
if (Alloca.size)
cstackadj = cat(cstackadj, prolog_setupalloca());
}
else
assert(Alloca.size == 0);
}
else if (xlocalsize)
{
assert(I32 || I64);
cstackadj = prolog_frameadj2(tyf, xlocalsize, &pushalloc);
BPoff += REGSIZE;
}
else
assert((localsize | Alloca.size) == 0 || (usednteh & NTEHjmonitor));
EBPtoESP += xlocalsize;
c = cat(c, cstackadj);
}
/* Win64 unwind needs the amount of code generated so far
*/
if (config.exe == EX_WIN64)
{
pinholeopt(c, NULL);
prolog_allocoffset = calcblksize(c);
}
#if SCPP
/* The idea is to generate trace for all functions if -Nc is not thrown.
* If -Nc is thrown, generate trace only for global COMDATs, because those
* are relevant to the FUNCTIONS statement in the linker .DEF file.
* This same logic should be in epilog().
*/
if (config.flags & CFGtrace &&
(!(config.flags4 & CFG4allcomdat) ||
funcsym_p->Sclass == SCcomdat ||
funcsym_p->Sclass == SCglobal ||
(config.flags2 & CFG2comdat && SymInline(funcsym_p))
)
)
{
unsigned spalign = 0;
int sz = Para.size + (needframe ? 0 : -REGSIZE) + localsize;
if (STACKALIGN == 16 && (sz & (STACKALIGN - 1)))
spalign = STACKALIGN - (sz & (STACKALIGN - 1));
if (spalign)
{ /* This could be avoided by moving the function call to after the
* registers are saved. But I don't remember why the call is here
* and not there.
*/
c = cod3_stackadj(c, spalign);
}
unsigned regsaved;
c = cat(c, prolog_trace(farfunc, ®saved));
if (spalign)
c = cod3_stackadj(c, -spalign);
useregs((ALLREGS | mBP | mES) & ~regsaved);
}
#endif
#if MARS
if (usednteh & NTEHjmonitor)
{ Symbol *sthis;
for (SYMIDX si = 0; 1; si++)
{ assert(si < globsym.top);
sthis = globsym.tab[si];
if (strcmp(sthis->Sident,"this") == 0)
break;
}
c = cat(c,nteh_monitor_prolog(sthis));
EBPtoESP += 3 * 4;
}
#endif
c = prolog_saveregs(c, topush, cfa_offset);
Lcont:
if (config.exe == EX_WIN64)