libgcc/config/sol2/gmon.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. [rescinded 22 July 1999]
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* Mangled into a form that works on Solaris 2/SPARC by Mark Eichin
 * for Cygnus Support, July 1992.
 *
 * Modified to support Solaris 2/x86 by J.W.Hawtin <oolon@ankh.org>, 14/8/96.
 *
 * It must be used in conjunction with sol2-gc1.S, which is used to start
 * and stop process monitoring.
 */

#include "tconfig.h"
#include "tsystem.h"
#include "auto-target.h"
#include <fcntl.h>		/* For creat.  */

extern void monstartup (char *, char *);
extern void _mcleanup (void);
static void internal_mcount (char *, unsigned short *) __attribute__ ((used));
static void moncontrol (int);

struct phdr {
  char *lpc;
  char *hpc;
  int ncnt;
};

#define HISTFRACTION	2
#define HISTCOUNTER	unsigned short
#define HASHFRACTION	1
#define ARCDENSITY	2
#define MINARCS		50

struct tostruct {
  char *selfpc;
  long count;
  unsigned short link;
};

struct rawarc {
  unsigned long raw_frompc;
  unsigned long raw_selfpc;
  long raw_count;
};

#define ROUNDDOWN(x, y)	(((x) / (y)) * (y))
#define ROUNDUP(x, y)	((((x) + (y) - 1) / (y)) * (y))

/* froms is actually a bunch of unsigned shorts indexing tos.  */
static int profiling = 3;
static unsigned short *froms;
static struct tostruct *tos = NULL;
static long tolimit = 0;
static char *s_lowpc = NULL;
static char *s_highpc = NULL;
static size_t s_textsize = 0;

static int ssiz;
static char *sbuf;
static int s_scale;
/* See profil(2) where this is describe (incorrectly).  */
#define	SCALE_1_TO_1	0x10000L

#define	MSG "No space for profiling buffer(s)\n"

void
monstartup (char *lowpc, char *highpc)
{
  size_t monsize;
  char *buffer;
  size_t o;

  /* Round lowpc and highpc to multiples of the density we're using
     so the rest of the scaling (here and in gprof) stays in ints.  */
  lowpc = (char *) ROUNDDOWN ((size_t) lowpc,
			      HISTFRACTION * sizeof (HISTCOUNTER));
  s_lowpc = lowpc;
  highpc = (char *) ROUNDUP ((size_t) highpc,
			     HISTFRACTION * sizeof (HISTCOUNTER));
  s_highpc = highpc;
  s_textsize = highpc - lowpc;
  monsize = (s_textsize / HISTFRACTION) + sizeof (struct phdr);
  buffer = sbrk (monsize);
  if (buffer == (void *) -1) {
    write (STDERR_FILENO, MSG, sizeof (MSG) - 1);
    return;
  }
  froms = sbrk (s_textsize / HASHFRACTION);
  if (froms == (void *) -1) {
    write (STDERR_FILENO, MSG, sizeof (MSG) - 1);
    froms = NULL;
    return;
  }
  tolimit = s_textsize * ARCDENSITY / 100;
  if (tolimit < MINARCS) {
    tolimit = MINARCS;
  } else if (tolimit > 65534) {
    tolimit = 65534;
  }
  tos = sbrk (tolimit * sizeof (struct tostruct));
  if (tos == (void *) -1) {
    write (STDERR_FILENO, MSG, sizeof (MSG) - 1);
    froms = NULL;
    tos = NULL;
    return;
  }
  tos[0].link = 0;
  sbuf = buffer;
  ssiz = monsize;
  ((struct phdr *) buffer)->lpc = lowpc;
  ((struct phdr *) buffer)->hpc = highpc;
  ((struct phdr *) buffer)->ncnt = ssiz;
  monsize -= sizeof (struct phdr);
  if (monsize <= 0)
    return;
  o = highpc - lowpc;
  if(monsize < o)
    s_scale = ((float) monsize / o) * SCALE_1_TO_1;
  else
    s_scale = SCALE_1_TO_1;
  moncontrol (1);
}

void
_mcleanup (void)
{
  int fd;
  int fromindex;
  int endfrom;
  char *frompc;
  int toindex;
  struct rawarc	rawarc;
  char *profdir;
  const char *proffile;
  char *progname;
  char buf[PATH_MAX];
  extern char **___Argv;

  moncontrol (0);

  if ((profdir = getenv ("PROFDIR")) != NULL) {
    /* If PROFDIR contains a null value, no profiling output is produced.  */
    if (*profdir == '\0') {
      return;
    }

    progname = strrchr (___Argv[0], '/');
    if (progname == NULL)
      progname = ___Argv[0];
    else
      progname++;

    sprintf (buf, "%s/%ld.%s", profdir, (long) getpid (), progname);
    proffile = buf;
  } else {
    proffile = "gmon.out";
  }

  fd = creat (proffile, 0666);
  if (fd < 0) {
    perror (proffile);
    return;
  }
#ifdef DEBUG
  fprintf (stderr, "[mcleanup] sbuf %#x ssiz %d\n", sbuf, ssiz);
#endif /* DEBUG */

  write (fd, sbuf, ssiz);
  endfrom = s_textsize / (HASHFRACTION * sizeof (*froms));
  for (fromindex = 0; fromindex < endfrom; fromindex++) {
    if (froms[fromindex] == 0) {
      continue;
    }
    frompc = s_lowpc + (fromindex * HASHFRACTION * sizeof (*froms));
    for (toindex = froms[fromindex];
	 toindex != 0;
	 toindex = tos[toindex].link) {
#ifdef DEBUG
      fprintf (stderr, "[mcleanup] frompc %#x selfpc %#x count %d\n",
	       frompc, tos[toindex].selfpc, tos[toindex].count);
#endif /* DEBUG */
      rawarc.raw_frompc = (unsigned long) frompc;
      rawarc.raw_selfpc = (unsigned long) tos[toindex].selfpc;
      rawarc.raw_count = tos[toindex].count;
      write (fd, &rawarc, sizeof (rawarc));
    }
  }
  close (fd);
}

/* Solaris 2 libraries use _mcount.  */
#if defined __i386__
asm(".globl _mcount\n"
    "	.type	_mcount, @function\n"
    "_mcount:\n"
    /* Save and restore the call-clobbered registers.  */
    "	pushl	%eax\n"
    "	pushl	%ecx\n"
    "	pushl	%edx\n"
    "	movl	12(%esp), %edx\n"
    "	movl	4(%ebp), %eax\n"
    "	call	internal_mcount\n"
    "	popl	%edx\n"
    "	popl	%ecx\n"
    "	popl	%eax\n"
    "	ret\n");
#elif defined __x86_64__
/* See GLIBC for additional information about this technique.  */
asm(".globl _mcount\n" 
    "	.type	_mcount, @function\n"
    "_mcount:\n"
    /* The compiler calls _mcount after the prologue, and does not
       save any of the registers.  Therefore we must preserve all
       seven registers which may contain function arguments.  */
    "	subq	$0x38, %rsp\n"
    "	movq	%rax, (%rsp)\n"
    "	movq	%rcx, 0x08(%rsp)\n"
    "	movq	%rdx, 0x10(%rsp)\n"
    "	movq	%rsi, 0x18(%rsp)\n"
    "	movq	%rdi, 0x20(%rsp)\n"
    "	movq	%r8, 0x28(%rsp)\n"
    "	movq	%r9, 0x30(%rsp)\n"
    /* Get SELFPC (pushed by the call to this function) and
       FROMPCINDEX (via the frame pointer).  */
    "	movq	0x38(%rsp), %rdi\n"
    "	movq	0x8(%rbp), %rsi\n"
    "	call	internal_mcount\n"
    /* Restore the saved registers.  */
    "	movq	0x30(%rsp), %r9\n"
    "	movq	0x28(%rsp), %r8\n"
    "	movq	0x20(%rsp), %rdi\n"
    "	movq	0x18(%rsp), %rsi\n"
    "	movq	0x10(%rsp), %rdx\n"
    "	movq	0x08(%rsp), %rcx\n"
    "	movq	(%rsp), %rax\n"
    "	addq	$0x38, %rsp\n"
    "	retq\n");
#elif defined __sparc__
/* The SPARC stack frame is only held together by the frame pointers
   in the register windows. According to the SVR4 SPARC ABI
   Supplement, Low Level System Information/Operating System
   Interface/Software Trap Types, a type 3 trap will flush all of the
   register windows to the stack, which will make it possible to walk
   the frames and find the return addresses.
	However, it seems awfully expensive to incur a trap (system
   call) for every function call. It turns out that "call" simply puts
   the return address in %o7 expecting the "save" in the procedure to
   shift it into %i7; this means that before the "save" occurs, %o7
   contains the address of the call to mcount, and %i7 still contains
   the caller above that. The asm mcount here simply saves those
   registers in argument registers and branches to internal_mcount,
   simulating a call with arguments.
	Kludges:
	1) the branch to internal_mcount is hard coded; it should be
   possible to tell asm to use the assembler-name of a symbol.
	2) in theory, the function calling mcount could have saved %i7
   somewhere and reused the register; in practice, I *think* this will
   break longjmp (and maybe the debugger) but I'm not certain. (I take
   some comfort in the knowledge that it will break the native mcount
   as well.)
	3) if builtin_return_address worked, this could be portable.
   However, it would really have to be optimized for arguments of 0
   and 1 and do something like what we have here in order to avoid the
   trap per function call performance hit. 
	4) the atexit and monsetup calls prevent this from simply
   being a leaf routine that doesn't do a "save" (and would thus have
   access to %o7 and %i7 directly) but the call to write() at the end
   would have also prevented this.

   -- [eichin:19920702.1107EST]  */
asm(".global _mcount\n"
    "_mcount:\n"
    /* i7 == last ret, -> frompcindex.  */
    "	mov	%i7, %o1\n"
    /* o7 == current ret, -> selfpc.  */
    "	mov	%o7, %o0\n"
    "	b,a	internal_mcount\n");
#endif

static void
internal_mcount (char *selfpc, unsigned short *frompcindex)
{
  struct tostruct *top;
  struct tostruct *prevtop;
  long toindex;
  static char already_setup;

/* Only necessary without the Solaris CRTs or a proper gcrt1.o, otherwise
   crtpg.o or gcrt1.o take care of that.

   FIXME: What about _init vs. _start on sparc?  */
#ifndef HAVE_SOLARIS_CRTS
  if(!already_setup) {
    extern char etext[];

    already_setup = 1;

#if defined __i386__
    /* <sys/vmparam.h> USERSTACK.  */
    monstartup ((char *) 0x8048000, etext);
#elif defined __x86_64__
    monstartup (NULL, etext);
#elif defined __sparc__
    {
      extern char _start[];
      extern char _init[];

      monstartup (_start < _init ? _start : _init, etext);
    }
#endif
    atexit (_mcleanup);
  }
#endif /* !HAVE_SOLARIS_CRTS */
  /* Check that we are profiling and that we aren't recursively invoked.  */
  if (profiling) {
    goto out;
  }
  profiling++;
  /* Check that frompcindex is a reasonable pc value.  For example: signal
     catchers get called from the stack, not from text space.  too bad.  */
  frompcindex = (unsigned short *) ((long) frompcindex - (long) s_lowpc);
  if ((unsigned long) frompcindex > s_textsize) {
    goto done;
  }
  frompcindex = &froms[((long) frompcindex) / (HASHFRACTION * sizeof (*froms))];
  toindex = *frompcindex;
  if (toindex == 0) {
    /* First time traversing this arc.  */
    toindex = ++tos[0].link;
    if (toindex >= tolimit) {
      goto overflow;
    }
    *frompcindex = toindex;
    top = &tos[toindex];
    top->selfpc = selfpc;
    top->count = 1;
    top->link = 0;
    goto done;
  }
  top = &tos[toindex];
  if (top->selfpc == selfpc) {
    /* arc at front of chain; usual case.  */
    top->count++;
    goto done;
  }
  /* Have to go looking down chain for it.  Top points to what we are
     looking at, prevtop points to previous top.  We know it is not at the
     head of the chain.  */
  for (; /* goto done */; ) {
    if (top->link == 0) {
      /* top is end of the chain and none of the chain had top->selfpc ==
	 selfpc, so we allocate a new tostruct and link it to the head of
	 the chain.  */
      toindex = ++tos[0].link;
      if (toindex >= tolimit) {
	goto overflow;
      }
      top = &tos[toindex];
      top->selfpc = selfpc;
      top->count = 1;
      top->link = *frompcindex;
      *frompcindex = toindex;
      goto done;
    }
    /* Otherwise, check the next arc on the chain.  */
    prevtop = top;
    top = &tos[top->link];
    if (top->selfpc == selfpc) {
      /* There it is.  Increment its count move it to the head of the
	 chain.  */
      top->count++;
      toindex = prevtop->link;
      prevtop->link = top->link;
      top->link = *frompcindex;
      *frompcindex = toindex;
      goto done;
    }

  }
 done:
  profiling--;
  /* ... and fall through. */
 out:
  /* Normal return restores saved registers.  */
  return;

 overflow:
  /* Halt further profiling.  */
  profiling++;

#define	TOLIMIT	"mcount: tos overflow\n"
  write (STDERR_FILENO, TOLIMIT, sizeof (TOLIMIT) - 1);
  goto out;
}

/* Control profiling.  Profiling is what mcount checks to see if all the
   data structures are ready.  */
static void
moncontrol (int mode)
{
  if (mode) {
    /* Start.  */
    profil ((unsigned short *) (sbuf + sizeof (struct phdr)),
	    ssiz - sizeof (struct phdr), (size_t) s_lowpc, s_scale);
    profiling = 0;
  } else {
    /* Stop.  */
    profil ((unsigned short *) 0, 0, 0, 0);
    profiling = 3;
  }
}