On Wed, Sep 27, 2023 at 07:17:22AM +0000, Richard Biener wrote:
> OK I guess. Can you summarize the limitations for non-POD types
> in the big comment at the start of vec.h?
Still haven't done that, but will do after we flesh out the details
below.
> (can we put in static_asserts
> in the places that obviously do not work?)
I've tried to do this though, I think the static_asserts will allow
making sure we only use what is supportable and will serve better than
any kind of comment.
But, I've run into quite a few triggered assertion failures with that, and
the question is what we want to do with them. Applying
--- gcc/vec.h.jj 2023-09-27 12:11:56.000000000 +0200
+++ gcc/vec.h 2023-09-27 12:39:50.971613964 +0200
@@ -1160,7 +1160,7 @@ template<typename T, typename A>
inline void
vec<T, A, vl_embed>::qsort (int (*cmp) (const void *, const void *))
{
- static_assert (std::is_trivially_copyable <T>::value, "");
+// static_assert (std::is_trivially_copyable <T>::value, "");
if (length () > 1)
gcc_qsort (address (), length (), sizeof (T), cmp);
}
@@ -1359,7 +1359,7 @@ inline void
vec<T, A, vl_embed>::quick_grow (unsigned len)
{
gcc_checking_assert (length () <= len && len <= m_vecpfx.m_alloc);
- static_assert (std::is_trivially_default_constructible <T>::value, "");
+// static_assert (std::is_trivially_default_constructible <T>::value, "");
m_vecpfx.m_num = len;
}
incremental patch makes stuff work (at lest make in gcc subdir for
x86_64-linux with --enable-languages=c,c++,fortran,lto succeeds), so it is just
those 2 asserts.
Following is full list of failures and discusses details.
dbgcnt.cc:132 limits[index].qsort (cmp_tuples);
T = std::pair<unsigned int, unsigned int>
where std::pair is not trivially copyable. Our qsort implementation uses
memcpys/memmoves to reshuffle the array elements (as it isn't inlined and
so can't use std::swap and the like), so I think we need the types trivially
copyable (or at least trivially copy assignable from the same type or
something similar if we close all eyes). Is there some std::pair
alternative which is trivially copyable, or do we need to define structures
to achieve that? Or just close all eyes and allow qsort/sort/stablesort
either on trivially copyable types, or on std::pair where both template
parameters are trivially copyable?
genrecog.cc:3466 candidates.qsort (subroutine_candidate_cmp);
T = std::pair<transition*, state_size>
ditto
dwarf2asm.cc:1061 temp.qsort (compare_strings);
T = std::pair<const char*, tree_node*>
ditto
tree-ssa-dce.cc:1776 args.qsort (sort_phi_args);
T = std::pair<edge_def*, unsigned int>
ditto
tree-ssa-loop-manip.cc:376 names.qsort (loop_name_cmp);
T = std::pair<int, int>
ditto
omp-oacc-neuter-broadcast.cc:1730 priority.qsort (sort_size_descending);
T = std::pair<int, tree_node*>
ditto
ipa-icf.cc:3087 to_split.qsort (sort_congruence_split);
T = std::pair<ipa_icf::congruence_class*, bitmap_head*>
ditto
ipa-icf.cc:3360 classes.qsort (sort_congruence_class_groups_by_decl_uid);
T = std::pair<ipa_icf::congruence_class_group*, int>
ditto
tree-vect-slp.cc:6991 li_scalar_costs.qsort (li_cost_vec_cmp);
T = std::pair<unsigned int, stmt_info_for_cost*>
ditto
tree-vect-slp.cc:7249 lane_defs.qsort (vld_cmp);
T = std::pair<unsigned int, tree_node*>
ditto
cfganal.cc:471 control_dependence_map.quick_grow (last_basic_block_for_fn
(cfun));
T = bitmap_head
This is a different case, bitmap_head has a non-trivial default constructor
that essentially fills it with zeros, and for quick_grow we have
quick_grow_cleared which default constructs elements, but quick_grow leaves
them unconstructed/uninitialized, which is why I wanted to add an assert
there, e.g. quick_grow on the wide_int/widest_int WIP would break stuff
terribly. In the cfganal.cc case, we call bitmap_initialize on it after
growing it, which overwrites all elements and doesn't depend on values of
any, so grow_cleared actually is invalid from strict C++ POV, but not
in reality. Do we still want the assert in and slow cfganal.cc slightly
by using quick_grow_cleared? Or another option would be to make
quick_grow work transparently the same as quick_grow_cleared for
non-trivially default constructible types. Though, I think it might be
better if people explicitly see that the operation is more expensive.
tree-ssa-loop-im.cc:2592 first_edge_seq.safe_grow
(fes_length
+
extra_refs.length ());
T = seq_entry
Here, seq_entry is:
struct seq_entry
{
seq_entry () {}
seq_entry (unsigned f, sm_kind k, tree fr = NULL)
: first (f), second (k), from (fr) {}
unsigned first;
sm_kind second;
tree from;
};
Wonder if making seq_entry () = default;
wouldn't cure this.
tree-ssa-loop-im.cc:3499 memory_accesses.refs_loaded_in_loop.quick_grow
(number_of_loops (cfun));
T = bitmap_head
like the cfganal.cc case.
tree-ssa-live.cc:1364 active.quick_grow (last_basic_block_for_fn (fn));
T = bitmap_head
ditto
rtl-ssa/blocks.cc:60 bb_phis.quick_grow (num_bb_indices);
T = rtl_ssa::function_info::bb_phi_info
This structure contains bitmap_head, so again isn't default constructible.
rtl-ssa/blocks.cc:617 frontiers.safe_grow (num_bb_indices);
T = bitmap_head
see above
tree-vect-data-refs.cc:5369 sel.quick_grow (nelt);
T = poly_int<1, long int>
Should this use poly_int_pod<1, long int> instead? Or quick_grow_cleared?
tree-vect-patterns.cc:2947 unprom.quick_grow (nops);
T = vect_unpromoted_value
Go for quick_grow_cleared? Something else?
tree-ssa-sccvn.cc:5562 accesses.quick_grow (accesses.length () +
1);
T = ao_ref
This isn't trivially copyable because of 3 poly_int64 members I believe.
Shall those be poly_int64_pod?
tree-vect-stmts.cc:2811 sel.quick_grow (count);
T = poly_int<1, long int>
see above
ipa-fnsummary.cc:683
avals->m_known_value_ranges.safe_grow (count, true);
T = Value_Range
Go for cleared?
tree-vect-slp.cc:8344 mask.quick_grow (count);
T = poly_int<1, long int>
see above
tree-vect-loop.cc:9042 sel.quick_grow (6);
T = poly_int<1, long int>
see above
config/i386/sse.md:16172 sel.quick_grow (8);
T = poly_int<1, long int>
see above
2023-09-27 Jakub Jelinek <ja...@redhat.com>
* vec.h (vec_destruct): New function template.
(release): Use it for non-trivially destructible T.
(truncate): Likewise.
(quick_push): Perform a placement new into slot
instead of assignment.
(pop): For non-trivially destructible T return void
rather than T & and destruct the popped element.
(quick_insert, ordered_remove): Note that they aren't suitable
for non-trivially copyable types. Add static_asserts for that.
(block_remove, qsort, sort, stablesort): Assert T is trivially
copyable.
(quick_grow): Assert T is trivially default constructible.
(quick_grow_cleared): Don't call quick_grow, instead inline it
by hand except for the new static_assert.
(gt_ggc_mx): Assert T is trivially destructable.
(auto_vec::operator=): Formatting fixes.
(auto_vec::auto_vec): Likewise.
(vec_safe_grow_cleared): Don't call vec_safe_grow, instead inline
it manually and call quick_grow_cleared method rather than quick_grow.
(safe_grow_cleared): Likewise.
* edit-context.cc (class line_event): Move definition earlier.
--- gcc/vec.h.jj 2023-09-27 10:38:50.635845540 +0200
+++ gcc/vec.h 2023-09-27 12:11:56.665586490 +0200
@@ -185,6 +185,16 @@ extern void dump_vec_loc_statistics (voi
/* Hashtable mapping vec addresses to descriptors. */
extern htab_t vec_mem_usage_hash;
+/* Destruct N elements in DST. */
+
+template <typename T>
+inline void
+vec_destruct (T *dst, unsigned n)
+{
+ for ( ; n; ++dst, --n)
+ dst->~T ();
+}
+
/* Control data for vectors. This contains the number of allocated
and used slots inside a vector. */
@@ -310,6 +320,9 @@ va_heap::release (vec<T, va_heap, vl_emb
if (v == NULL)
return;
+ if (!std::is_trivially_destructible <T>::value)
+ vec_destruct (v->address (), v->length ());
+
if (GATHER_STATISTICS)
v->m_vecpfx.release_overhead (v, elt_size * v->allocated (),
v->allocated (), true);
@@ -588,7 +601,10 @@ public:
void splice (const vec &);
void splice (const vec *src);
T *quick_push (const T &);
- T &pop (void);
+ using pop_ret_type
+ = typename std::conditional <std::is_trivially_destructible <T>::value,
+ T &, void>::type;
+ pop_ret_type pop (void);
void truncate (unsigned);
void quick_insert (unsigned, const T &);
void ordered_remove (unsigned);
@@ -735,8 +751,9 @@ vec_safe_grow_cleared (vec<T, A, vl_embe
bool exact = false CXX_MEM_STAT_INFO)
{
unsigned oldlen = vec_safe_length (v);
- vec_safe_grow (v, len, exact PASS_MEM_STAT);
- vec_default_construct (v->address () + oldlen, len - oldlen);
+ gcc_checking_assert (len >= oldlen);
+ vec_safe_reserve (v, len - oldlen, exact PASS_MEM_STAT);
+ v->quick_grow_cleared (len);
}
@@ -1005,19 +1022,24 @@ vec<T, A, vl_embed>::quick_push (const T
{
gcc_checking_assert (space (1));
T *slot = &address ()[m_vecpfx.m_num++];
- *slot = obj;
+ ::new (static_cast<void*>(slot)) T (obj);
return slot;
}
-/* Pop and return the last element off the end of the vector. */
+/* Pop and return a reference to the last element off the end of the
+ vector. If T has non-trivial destructor, this method just pops
+ the element and returns void type. */
template<typename T, typename A>
-inline T &
+inline typename vec<T, A, vl_embed>::pop_ret_type
vec<T, A, vl_embed>::pop (void)
{
gcc_checking_assert (length () > 0);
- return address ()[--m_vecpfx.m_num];
+ T &last = address ()[--m_vecpfx.m_num];
+ if (!std::is_trivially_destructible <T>::value)
+ last.~T ();
+ return static_cast <pop_ret_type> (last);
}
@@ -1028,13 +1050,17 @@ template<typename T, typename A>
inline void
vec<T, A, vl_embed>::truncate (unsigned size)
{
- gcc_checking_assert (length () >= size);
+ unsigned l = length ();
+ gcc_checking_assert (l >= size);
+ if (!std::is_trivially_destructible <T>::value)
+ vec_destruct (address () + l, l - size);
m_vecpfx.m_num = size;
}
/* Insert an element, OBJ, at the IXth position of this vector. There
- must be sufficient space. */
+ must be sufficient space. This operation is not suitable for non-trivially
+ copyable types. */
template<typename T, typename A>
inline void
@@ -1042,6 +1068,7 @@ vec<T, A, vl_embed>::quick_insert (unsig
{
gcc_checking_assert (length () < allocated ());
gcc_checking_assert (ix <= length ());
+ static_assert (std::is_trivially_copyable <T>::value, "");
T *slot = &address ()[ix];
memmove (slot + 1, slot, (m_vecpfx.m_num++ - ix) * sizeof (T));
*slot = obj;
@@ -1050,13 +1077,14 @@ vec<T, A, vl_embed>::quick_insert (unsig
/* Remove an element from the IXth position of this vector. Ordering of
remaining elements is preserved. This is an O(N) operation due to
- memmove. */
+ memmove. Not suitable for non-trivially copyable types. */
template<typename T, typename A>
inline void
vec<T, A, vl_embed>::ordered_remove (unsigned ix)
{
gcc_checking_assert (ix < length ());
+ static_assert (std::is_trivially_copyable <T>::value, "");
T *slot = &address ()[ix];
memmove (slot, slot + 1, (--m_vecpfx.m_num - ix) * sizeof (T));
}
@@ -1104,6 +1132,7 @@ inline void
vec<T, A, vl_embed>::unordered_remove (unsigned ix)
{
gcc_checking_assert (ix < length ());
+ static_assert (std::is_trivially_copyable <T>::value, "");
T *p = address ();
p[ix] = p[--m_vecpfx.m_num];
}
@@ -1117,6 +1146,7 @@ inline void
vec<T, A, vl_embed>::block_remove (unsigned ix, unsigned len)
{
gcc_checking_assert (ix + len <= length ());
+ static_assert (std::is_trivially_copyable <T>::value, "");
T *slot = &address ()[ix];
m_vecpfx.m_num -= len;
memmove (slot, slot + len, (m_vecpfx.m_num - ix) * sizeof (T));
@@ -1130,6 +1160,7 @@ template<typename T, typename A>
inline void
vec<T, A, vl_embed>::qsort (int (*cmp) (const void *, const void *))
{
+ static_assert (std::is_trivially_copyable <T>::value, "");
if (length () > 1)
gcc_qsort (address (), length (), sizeof (T), cmp);
}
@@ -1142,6 +1173,7 @@ inline void
vec<T, A, vl_embed>::sort (int (*cmp) (const void *, const void *, void *),
void *data)
{
+ static_assert (std::is_trivially_copyable <T>::value, "");
if (length () > 1)
gcc_sort_r (address (), length (), sizeof (T), cmp, data);
}
@@ -1154,6 +1186,7 @@ inline void
vec<T, A, vl_embed>::stablesort (int (*cmp) (const void *, const void *,
void *), void *data)
{
+ static_assert (std::is_trivially_copyable <T>::value, "");
if (length () > 1)
gcc_stablesort_r (address (), length (), sizeof (T), cmp, data);
}
@@ -1326,6 +1359,7 @@ inline void
vec<T, A, vl_embed>::quick_grow (unsigned len)
{
gcc_checking_assert (length () <= len && len <= m_vecpfx.m_alloc);
+ static_assert (std::is_trivially_default_constructible <T>::value, "");
m_vecpfx.m_num = len;
}
@@ -1339,7 +1373,8 @@ vec<T, A, vl_embed>::quick_grow_cleared
{
unsigned oldlen = length ();
size_t growby = len - oldlen;
- quick_grow (len);
+ gcc_checking_assert (length () <= len && len <= m_vecpfx.m_alloc);
+ m_vecpfx.m_num = len;
if (growby != 0)
vec_default_construct (address () + oldlen, growby);
}
@@ -1350,6 +1385,7 @@ template<typename T>
void
gt_ggc_mx (vec<T, va_gc> *v)
{
+ static_assert (std::is_trivially_destructible <T>::value, "");
extern void gt_ggc_mx (T &);
for (unsigned i = 0; i < v->length (); i++)
gt_ggc_mx ((*v)[i]);
@@ -1359,6 +1395,7 @@ template<typename T>
void
gt_ggc_mx (vec<T, va_gc_atomic, vl_embed> *v ATTRIBUTE_UNUSED)
{
+ static_assert (std::is_trivially_destructible <T>::value, "");
/* Nothing to do. Vectors of atomic types wrt GC do not need to
be traversed. */
}
@@ -1518,7 +1555,10 @@ public:
void safe_splice (const vec & CXX_MEM_STAT_INFO);
T *quick_push (const T &);
T *safe_push (const T &CXX_MEM_STAT_INFO);
- T &pop (void);
+ using pop_ret_type
+ = typename std::conditional <std::is_trivially_destructible <T>::value,
+ T &, void>::type;
+ pop_ret_type pop (void);
void truncate (unsigned);
void safe_grow (unsigned, bool = false CXX_MEM_STAT_INFO);
void safe_grow_cleared (unsigned, bool = false CXX_MEM_STAT_INFO);
@@ -1627,8 +1667,8 @@ public:
auto_vec& operator= (vec<T, va_heap>&& r)
{
- if (this == &r)
- return *this;
+ if (this == &r)
+ return *this;
gcc_assert (!r.using_auto_storage ());
this->release ();
@@ -1639,8 +1679,8 @@ public:
auto_vec& operator= (auto_vec<T> &&r)
{
- if (this == &r)
- return *this;
+ if (this == &r)
+ return *this;
gcc_assert (!r.using_auto_storage ());
this->release ();
@@ -1660,7 +1700,7 @@ public:
// You probably don't want to copy a vector, so these are deleted to prevent
// unintentional use. If you really need a copy of the vectors contents you
// can use copy ().
- auto_vec(const auto_vec &) = delete;
+ auto_vec (const auto_vec &) = delete;
auto_vec &operator= (const auto_vec &) = delete;
};
@@ -1986,10 +2026,12 @@ vec<T, va_heap, vl_ptr>::safe_push (cons
}
-/* Pop and return the last element off the end of the vector. */
+/* Pop and return a reference to the last element off the end of the
+ vector. If T has non-trivial destructor, this method just pops
+ last element and returns void. */
template<typename T>
-inline T &
+inline typename vec<T, va_heap, vl_ptr>::pop_ret_type
vec<T, va_heap, vl_ptr>::pop (void)
{
return m_vec->pop ();
@@ -2038,10 +2080,12 @@ vec<T, va_heap, vl_ptr>::safe_grow_clear
MEM_STAT_DECL)
{
unsigned oldlen = length ();
- size_t growby = len - oldlen;
- safe_grow (len, exact PASS_MEM_STAT);
- if (growby != 0)
- vec_default_construct (address () + oldlen, growby);
+ gcc_checking_assert (oldlen <= len);
+ reserve (len - oldlen, exact PASS_MEM_STAT);
+ if (m_vec)
+ m_vec->quick_grow_cleared (len);
+ else
+ gcc_checking_assert (len == 0);
}
--- gcc/edit-context.cc.jj 2023-09-27 10:37:38.600848724 +0200
+++ gcc/edit-context.cc 2023-09-27 10:40:04.834812220 +0200
@@ -122,6 +122,32 @@ class added_line
int m_len;
};
+/* Class for representing edit events that have occurred on one line of
+ one file: the replacement of some text betweeen some columns
+ on the line.
+
+ Subsequent events will need their columns adjusting if they're
+ are on this line and their column is >= the start point. */
+
+class line_event
+{
+ public:
+ line_event (int start, int next, int len) : m_start (start),
+ m_delta (len - (next - start)) {}
+
+ int get_effective_column (int orig_column) const
+ {
+ if (orig_column >= m_start)
+ return orig_column += m_delta;
+ else
+ return orig_column;
+ }
+
+ private:
+ int m_start;
+ int m_delta;
+};
+
/* The state of one edited line within an edited_file.
As well as the current content of the line, it contains a record of
the changes, so that further changes can be applied in the correct
@@ -172,32 +198,6 @@ class edited_line
auto_vec <added_line *> m_predecessors;
};
-/* Class for representing edit events that have occurred on one line of
- one file: the replacement of some text betweeen some columns
- on the line.
-
- Subsequent events will need their columns adjusting if they're
- are on this line and their column is >= the start point. */
-
-class line_event
-{
- public:
- line_event (int start, int next, int len) : m_start (start),
- m_delta (len - (next - start)) {}
-
- int get_effective_column (int orig_column) const
- {
- if (orig_column >= m_start)
- return orig_column += m_delta;
- else
- return orig_column;
- }
-
- private:
- int m_start;
- int m_delta;
-};
-
/* Forward decls. */
static void
Jakub
