gcc/vec.c

/* Vector API for GNU compiler.
   Copyright (C) 2004-2018 Free Software Foundation, Inc.
   Contributed by Nathan Sidwell <nathan@codesourcery.com>
   Re-implemented in C++ by Diego Novillo <dnovillo@google.com>

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

/* This file is compiled twice: once for the generator programs
   once for the compiler.  */
#ifdef GENERATOR_FILE
#include "bconfig.h"
#else
#include "config.h"
#endif

#include "system.h"
#include "coretypes.h"
#include "hash-table.h"
#include "selftest.h"
#ifdef GENERATOR_FILE
#include "errors.h"
#else
#include "input.h"
#include "diagnostic-core.h"
#endif

/* vNULL is an empty type with a template cast operation that returns
   a zero-initialized vec<T, A, L> instance.  Use this when you want
   to assign nil values to new vec instances or pass a nil vector as
   a function call argument.

   We use this technique because vec<T, A, L> must be PODs (they are
   stored in unions and passed in vararg functions), this means that
   they cannot have ctors/dtors.  */
vnull vNULL;

/* Vector memory usage.  */
struct vec_usage: public mem_usage
{
  /* Default constructor.  */
  vec_usage (): m_items (0), m_items_peak (0) {}

  /* Constructor.  */
  vec_usage (size_t allocated, size_t times, size_t peak,
	     size_t items, size_t items_peak)
    : mem_usage (allocated, times, peak),
    m_items (items), m_items_peak (items_peak) {}

  /* Sum the usage with SECOND usage.  */
  vec_usage
  operator+ (const vec_usage &second)
  {
    return vec_usage (m_allocated + second.m_allocated,
		      m_times + second.m_times,
		      m_peak + second.m_peak,
		      m_items + second.m_items,
		      m_items_peak + second.m_items_peak);
  }

  /* Dump usage coupled to LOC location, where TOTAL is sum of all rows.  */
  inline void
  dump (mem_location *loc, mem_usage &total) const
  {
    char s[4096];
    sprintf (s, "%s:%i (%s)", loc->get_trimmed_filename (),
	     loc->m_line, loc->m_function);

    s[48] = '\0';

    fprintf (stderr, "%-48s %10li:%4.1f%%%10li%10li:%4.1f%%%11li%11li\n", s,
	     (long)m_allocated, m_allocated * 100.0 / total.m_allocated,
	     (long)m_peak, (long)m_times, m_times * 100.0 / total.m_times,
	     (long)m_items, (long)m_items_peak);
  }

  /* Dump footer.  */
  inline void
  dump_footer ()
  {
    print_dash_line ();
    fprintf (stderr, "%s%55li%25li%17li\n", "Total", (long)m_allocated,
	     (long)m_times, (long)m_items);
    print_dash_line ();
  }

  /* Dump header with NAME.  */
  static inline void
  dump_header (const char *name)
  {
    fprintf (stderr, "%-48s %11s%15s%10s%17s%11s\n", name, "Leak", "Peak",
	     "Times", "Leak items", "Peak items");
    print_dash_line ();
  }

  /* Current number of items allocated.  */
  size_t m_items;
  /* Peak value of number of allocated items.  */
  size_t m_items_peak;
};

/* Vector memory description.  */
static mem_alloc_description <vec_usage> vec_mem_desc;

/* Account the overhead.  */

void
vec_prefix::register_overhead (void *ptr, size_t size, size_t elements
			       MEM_STAT_DECL)
{
  vec_mem_desc.register_descriptor (ptr, VEC_ORIGIN, false
				    FINAL_PASS_MEM_STAT);
  vec_usage *usage = vec_mem_desc.register_instance_overhead (size, ptr);
  usage->m_items += elements;
  if (usage->m_items_peak < usage->m_items)
    usage->m_items_peak = usage->m_items;
}

/* Notice that the memory allocated for the vector has been freed.  */

void
vec_prefix::release_overhead (void *ptr, size_t size, bool in_dtor
			      MEM_STAT_DECL)
{
  if (!vec_mem_desc.contains_descriptor_for_instance (ptr))
    vec_mem_desc.register_descriptor (ptr, VEC_ORIGIN,
				      false FINAL_PASS_MEM_STAT);
  vec_mem_desc.release_instance_overhead (ptr, size, in_dtor);
}


/* Calculate the number of slots to reserve a vector, making sure that
   it is of at least DESIRED size by growing ALLOC exponentially.  */

unsigned
vec_prefix::calculate_allocation_1 (unsigned alloc, unsigned desired)
{
  /* We must have run out of room.  */
  gcc_assert (alloc < desired);

  /* Exponential growth. */
  if (!alloc)
    alloc = 4;
  else if (alloc < 16)
    /* Double when small.  */
    alloc = alloc * 2;
  else
    /* Grow slower when large.  */
    alloc = (alloc * 3 / 2);

  /* If this is still too small, set it to the right size. */
  if (alloc < desired)
    alloc = desired;
  return alloc;
}

/* Dump per-site memory statistics.  */

void
dump_vec_loc_statistics (void)
{
  vec_mem_desc.dump (VEC_ORIGIN);
}

#if CHECKING_P
/* Report qsort comparator CMP consistency check failure with P1, P2, P3 as
   witness elements.  */
ATTRIBUTE_NORETURN ATTRIBUTE_COLD
static void
qsort_chk_error (const void *p1, const void *p2, const void *p3,
		 int (*cmp) (const void *, const void *))
{
  if (!p3)
    {
      int r1 = cmp (p1, p2), r2 = cmp (p2, p1);
      error ("qsort comparator not anti-commutative: %d, %d", r1, r2);
    }
  else if (p1 == p2)
    {
      int r = cmp (p1, p3);
      error ("qsort comparator non-negative on sorted output: %d", r);
    }
  else
    {
      int r1 = cmp (p1, p2), r2 = cmp (p2, p3), r3 = cmp (p1, p3);
      error ("qsort comparator not transitive: %d, %d, %d", r1, r2, r3);
    }
  internal_error ("qsort checking failed");
}

/* Wrapper around qsort with checking that CMP is consistent on given input.

   Strictly speaking, passing invalid (non-transitive, non-anti-commutative)
   comparators to libc qsort can result in undefined behavior.  Therefore we
   should ideally perform consistency checks prior to invoking qsort, but in
   order to do that optimally we'd need to sort the array ourselves beforehand
   with a sorting routine known to be "safe".  Instead, we expect that most
   implementations in practice will still produce some permutation of input
   array even for invalid comparators, which enables us to perform checks on
   the output array.  */
void
qsort_chk (void *base, size_t n, size_t size,
	   int (*cmp)(const void *, const void *))
{
  (qsort) (base, n, size, cmp);
#if 0
#define LIM(n) (n)
#else
  /* Limit overall time complexity to O(n log n).  */
#define LIM(n) ((n) <= 16 ? (n) : 12 + floor_log2 (n))
#endif
#define ELT(i) ((const char *) base + (i) * size)
#define CMP(i, j) cmp (ELT (i), ELT (j))
#define ERR2(i, j) qsort_chk_error (ELT (i), ELT (j), NULL, cmp)
#define ERR3(i, j, k) qsort_chk_error (ELT (i), ELT (j), ELT (k), cmp)
  size_t i1, i2, i, j;
  /* This outer loop iterates over maximum spans [i1, i2) such that
     elements within each span compare equal to each other.  */
  for (i1 = 0; i1 < n; i1 = i2)
    {
      /* Position i2 one past last element that compares equal to i1'th.  */
      for (i2 = i1 + 1; i2 < n; i2++)
	if (CMP (i1, i2))
	  break;
	else if (CMP (i2, i1))
	  return ERR2 (i1, i2);
      size_t lim1 = LIM (i2 - i1), lim2 = LIM (n - i2);
      /* Verify that other pairs within current span compare equal.  */
      for (i = i1 + 1; i + 1 < i2; i++)
	for (j = i + 1; j < i1 + lim1; j++)
	  if (CMP (i, j))
	    return ERR3 (i, i1, j);
	  else if (CMP (j, i))
	    return ERR2 (i, j);
      /* Verify that elements within this span compare less than
         elements beyond the span.  */
      for (i = i1; i < i2; i++)
	for (j = i2; j < i2 + lim2; j++)
	  if (CMP (i, j) >= 0)
	    return ERR3 (i, i1, j);
	  else if (CMP (j, i) <= 0)
	    return ERR2 (i, j);
    }
#undef ERR3
#undef ERR2
#undef CMP
#undef ELT
#undef LIM
}
#endif /* #if CHECKING_P */

#ifndef GENERATOR_FILE
#if CHECKING_P

namespace selftest {

/* Selftests.  */

/* Call V.safe_push for all ints from START up to, but not including LIMIT.
   Helper function for selftests.  */

static void
safe_push_range (vec <int>&v, int start, int limit)
{
  for (int i = start; i < limit; i++)
    v.safe_push (i);
}

/* Verify that vec::quick_push works correctly.  */

static void
test_quick_push ()
{
  auto_vec <int> v;
  ASSERT_EQ (0, v.length ());
  v.reserve (3);
  ASSERT_EQ (0, v.length ());
  ASSERT_TRUE (v.space (3));
  v.quick_push (5);
  v.quick_push (6);
  v.quick_push (7);
  ASSERT_EQ (3, v.length ());
  ASSERT_EQ (5, v[0]);
  ASSERT_EQ (6, v[1]);
  ASSERT_EQ (7, v[2]);
}

/* Verify that vec::safe_push works correctly.  */

static void
test_safe_push ()
{
  auto_vec <int> v;
  ASSERT_EQ (0, v.length ());
  v.safe_push (5);
  v.safe_push (6);
  v.safe_push (7);
  ASSERT_EQ (3, v.length ());
  ASSERT_EQ (5, v[0]);
  ASSERT_EQ (6, v[1]);
  ASSERT_EQ (7, v[2]);
}

/* Verify that vec::truncate works correctly.  */

static void
test_truncate ()
{
  auto_vec <int> v;
  ASSERT_EQ (0, v.length ());
  safe_push_range (v, 0, 10);
  ASSERT_EQ (10, v.length ());

  v.truncate (5);
  ASSERT_EQ (5, v.length ());
}

/* Verify that vec::safe_grow_cleared works correctly.  */

static void
test_safe_grow_cleared ()
{
  auto_vec <int> v;
  ASSERT_EQ (0, v.length ());
  v.safe_grow_cleared (50);
  ASSERT_EQ (50, v.length ());
  ASSERT_EQ (0, v[0]);
  ASSERT_EQ (0, v[49]);
}

/* Verify that vec::pop works correctly.  */

static void
test_pop ()
{
  auto_vec <int> v;
  safe_push_range (v, 5, 20);
  ASSERT_EQ (15, v.length ());

  int last = v.pop ();
  ASSERT_EQ (19, last);
  ASSERT_EQ (14, v.length ());
}

/* Verify that vec::safe_insert works correctly.  */

static void
test_safe_insert ()
{
  auto_vec <int> v;
  safe_push_range (v, 0, 10);
  v.safe_insert (5, 42);
  ASSERT_EQ (4, v[4]);
  ASSERT_EQ (42, v[5]);
  ASSERT_EQ (5, v[6]);
  ASSERT_EQ (11, v.length ());
}

/* Verify that vec::ordered_remove works correctly.  */

static void
test_ordered_remove ()
{
  auto_vec <int> v;
  safe_push_range (v, 0, 10);
  v.ordered_remove (5);
  ASSERT_EQ (4, v[4]);
  ASSERT_EQ (6, v[5]);
  ASSERT_EQ (9, v.length ());
}

/* Verify that vec::unordered_remove works correctly.  */

static void
test_unordered_remove ()
{
  auto_vec <int> v;
  safe_push_range (v, 0, 10);
  v.unordered_remove (5);
  ASSERT_EQ (9, v.length ());
}

/* Verify that vec::block_remove works correctly.  */

static void
test_block_remove ()
{
  auto_vec <int> v;
  safe_push_range (v, 0, 10);
  v.block_remove (5, 3);
  ASSERT_EQ (3, v[3]);
  ASSERT_EQ (4, v[4]);
  ASSERT_EQ (8, v[5]);
  ASSERT_EQ (9, v[6]);
  ASSERT_EQ (7, v.length ());
}

/* Comparator for use by test_qsort.  */

static int
reverse_cmp (const void *p_i, const void *p_j)
{
  return *(const int *)p_j - *(const int *)p_i;
}

/* Verify that vec::qsort works correctly.  */

static void
test_qsort ()
{
  auto_vec <int> v;
  safe_push_range (v, 0, 10);
  v.qsort (reverse_cmp);
  ASSERT_EQ (9, v[0]);
  ASSERT_EQ (8, v[1]);
  ASSERT_EQ (1, v[8]);
  ASSERT_EQ (0, v[9]);
  ASSERT_EQ (10, v.length ());
}

/* Run all of the selftests within this file.  */

void
vec_c_tests ()
{
  test_quick_push ();
  test_safe_push ();
  test_truncate ();
  test_safe_grow_cleared ();
  test_pop ();
  test_safe_insert ();
  test_ordered_remove ();
  test_unordered_remove ();
  test_block_remove ();
  test_qsort ();
}

} // namespace selftest

#endif /* #if CHECKING_P */
#endif /* #ifndef GENERATOR_FILE */