* RFA (hash-*): PATCH for c++/68309
@ 2015-12-10 22:03 Jason Merrill
2015-12-11 10:11 ` Richard Biener
2015-12-15 0:50 ` Trevor Saunders
0 siblings, 2 replies; 6+ messages in thread
From: Jason Merrill @ 2015-12-10 22:03 UTC (permalink / raw)
To: gcc-patches List, Jeffrey A Law; +Cc: Richard Sandiford, Trevor Saunders
[-- Attachment #1: Type: text/plain, Size: 641 bytes --]
The C++ front end uses a temporary hash table to remember
specializations of local variables during template instantiations. In a
nested function such as a lambda or local class member function, we need
to retain the elements from the enclosing function's
local_specializations table; otherwise the testcase crashes because we
don't find a local specialization for the non-captured use of 'args' in
the decltype.
This patch addresses that by making a copy of the enclosing
local_specializations table if it exists; to enable that I've added copy
constructors to hash_table and hash_map.
Tested x86_64-pc-linux-gnu. OK for trunk?
[-- Attachment #2: 68309.patch --]
[-- Type: text/x-patch, Size: 3811 bytes --]
commit 2dfc74fa638b7255658f194c82308e8bf8ada9f9
Author: Jason Merrill <jason@redhat.com>
Date: Thu Dec 10 15:37:50 2015 -0500
PR c++/68309
gcc/
* hash-table.h: Add copy constructor.
* hash-map.h: Add copy constructor.
gcc/cp/
* pt.c (instantiate_decl): Copy local_specializations for nested
function.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 0e087a6..5db3a32 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -21725,8 +21725,13 @@ instantiate_decl (tree d, int defer_ok,
template from within the body of another. */
saved_local_specializations = local_specializations;
- /* Set up the list of local specializations. */
- local_specializations = new hash_map<tree, tree>;
+ /* Set up the list of local specializations, copying the current
+ list if there is one. */
+ if (local_specializations)
+ local_specializations
+ = new hash_map<tree, tree> (*local_specializations);
+ else
+ local_specializations = new hash_map<tree, tree>;
/* Set up context. */
if (DECL_OMP_DECLARE_REDUCTION_P (code_pattern)
diff --git a/gcc/hash-map.h b/gcc/hash-map.h
index b83708c..9b3d1e9 100644
--- a/gcc/hash-map.h
+++ b/gcc/hash-map.h
@@ -110,6 +110,11 @@ public:
bool gather_mem_stats = true CXX_MEM_STAT_INFO)
: m_table (n, ggc, gather_mem_stats, HASH_MAP_ORIGIN PASS_MEM_STAT) {}
+ hash_map (const hash_map &h, bool ggc = false,
+ bool gather_mem_stats = true CXX_MEM_STAT_INFO)
+ : m_table (h.m_table, ggc, gather_mem_stats,
+ HASH_MAP_ORIGIN PASS_MEM_STAT) {}
+
/* Create a hash_map in ggc memory. */
static hash_map *create_ggc (size_t size, bool gather_mem_stats = true
CXX_MEM_STAT_INFO)
diff --git a/gcc/hash-table.h b/gcc/hash-table.h
index 192be30..d172841 100644
--- a/gcc/hash-table.h
+++ b/gcc/hash-table.h
@@ -364,6 +364,10 @@ public:
explicit hash_table (size_t, bool ggc = false, bool gather_mem_stats = true,
mem_alloc_origin origin = HASH_TABLE_ORIGIN
CXX_MEM_STAT_INFO);
+ hash_table (const hash_table &, bool ggc = false,
+ bool gather_mem_stats = true,
+ mem_alloc_origin origin = HASH_TABLE_ORIGIN
+ CXX_MEM_STAT_INFO);
~hash_table ();
/* Create a hash_table in gc memory. */
@@ -580,6 +584,27 @@ hash_table<Descriptor, Allocator>::hash_table (size_t size, bool ggc, bool
}
template<typename Descriptor, template<typename Type> class Allocator>
+hash_table<Descriptor, Allocator>::hash_table (const hash_table &h, bool ggc,
+ bool gather_mem_stats,
+ mem_alloc_origin origin
+ MEM_STAT_DECL) :
+ m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
+ m_searches (0), m_collisions (0),
+ m_ggc (ggc), m_gather_mem_stats (gather_mem_stats)
+{
+ size_t size = h.m_size;
+
+ if (m_gather_mem_stats)
+ hash_table_usage.register_descriptor (this, origin, ggc
+ FINAL_PASS_MEM_STAT);
+
+ m_entries = alloc_entries (size PASS_MEM_STAT);
+ memcpy (m_entries, h.m_entries, size * sizeof (value_type));
+ m_size = size;
+ m_size_prime_index = h.m_size_prime_index;
+}
+
+template<typename Descriptor, template<typename Type> class Allocator>
hash_table<Descriptor, Allocator>::~hash_table ()
{
for (size_t i = m_size - 1; i < m_size; i--)
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
new file mode 100644
index 0000000..76b6b3f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
@@ -0,0 +1,9 @@
+// PR c++/68309
+// { dg-do compile { target c++11 } }
+
+template <class... Ts> void f(Ts...);
+template <class T> T g(T);
+template <typename... Ts> void print(Ts... args) {
+ [&] { f(g<decltype(args)>(args)...); }();
+}
+int main() { print(5.2); }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA (hash-*): PATCH for c++/68309
2015-12-10 22:03 RFA (hash-*): PATCH for c++/68309 Jason Merrill
@ 2015-12-11 10:11 ` Richard Biener
2015-12-11 19:06 ` Jason Merrill
2015-12-15 0:50 ` Trevor Saunders
1 sibling, 1 reply; 6+ messages in thread
From: Richard Biener @ 2015-12-11 10:11 UTC (permalink / raw)
To: Jason Merrill
Cc: gcc-patches List, Jeffrey A Law, Richard Sandiford, Trevor Saunders
On Thu, Dec 10, 2015 at 11:03 PM, Jason Merrill <jason@redhat.com> wrote:
> The C++ front end uses a temporary hash table to remember specializations of
> local variables during template instantiations. In a nested function such
> as a lambda or local class member function, we need to retain the elements
> from the enclosing function's local_specializations table; otherwise the
> testcase crashes because we don't find a local specialization for the
> non-captured use of 'args' in the decltype.
>
> This patch addresses that by making a copy of the enclosing
> local_specializations table if it exists; to enable that I've added copy
> constructors to hash_table and hash_map.
>
> Tested x86_64-pc-linux-gnu. OK for trunk?
I don't think you can copy the elements with memcpy they may be C++ classes
that are not copyable. Also watch out for the bool gather_mem_stats = true
to bool gather_mem_stats = GATHER_STATISTICS change if that crosses your
change.
I also think copying hash tables should be discouraged ;) I wonder if you
can get around the copying by adding a generation count (to easily "backtrack")
instead.
Richard.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA (hash-*): PATCH for c++/68309
2015-12-11 10:11 ` Richard Biener
@ 2015-12-11 19:06 ` Jason Merrill
2015-12-14 8:51 ` Richard Biener
0 siblings, 1 reply; 6+ messages in thread
From: Jason Merrill @ 2015-12-11 19:06 UTC (permalink / raw)
To: Richard Biener
Cc: gcc-patches List, Jeffrey A Law, Richard Sandiford, Trevor Saunders
[-- Attachment #1: Type: text/plain, Size: 1709 bytes --]
On 12/11/2015 05:10 AM, Richard Biener wrote:
> On Thu, Dec 10, 2015 at 11:03 PM, Jason Merrill <jason@redhat.com> wrote:
>> The C++ front end uses a temporary hash table to remember specializations of
>> local variables during template instantiations. In a nested function such
>> as a lambda or local class member function, we need to retain the elements
>> from the enclosing function's local_specializations table; otherwise the
>> testcase crashes because we don't find a local specialization for the
>> non-captured use of 'args' in the decltype.
>>
>> This patch addresses that by making a copy of the enclosing
>> local_specializations table if it exists; to enable that I've added copy
>> constructors to hash_table and hash_map.
>>
>> Tested x86_64-pc-linux-gnu. OK for trunk?
>
> I don't think you can copy the elements with memcpy they may be C++ classes
> that are not copyable.
True. Fixed thus:
> + for (size_t i = 0; i < size; ++i)
> + {
> + value_type &entry = h.m_entries[i];
> + if (is_deleted (entry))
> + mark_deleted (m_entries[i]);
> + else if (!is_empty (entry))
> + m_entries[i] = entry;
> + }
> Also watch out for the bool gather_mem_stats = true
> to bool gather_mem_stats = GATHER_STATISTICS change if that crosses your
> change.
OK.
> I also think copying hash tables should be discouraged ;) I wonder if you
> can get around the copying by adding a generation count (to easily "backtrack")
> instead.
I considered having a chain of tables to check, to handle generations,
but I figured that the tables in question were small enough (only
containing local variables for a single function) that a simple copy was
reasonable.
Jason
[-- Attachment #2: 68309.patch --]
[-- Type: text/x-patch, Size: 3956 bytes --]
commit ae8c23201f9a057516f081d4d9fde1fb3281153f
Author: Jason Merrill <jason@redhat.com>
Date: Thu Dec 10 15:37:50 2015 -0500
PR c++/68309
gcc/
* hash-table.h: Add copy constructor.
* hash-map.h: Add copy constructor.
gcc/cp/
* pt.c (instantiate_decl): Copy local_specializations for nested
function.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 60cc94c..a45e6df 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -21725,8 +21725,13 @@ instantiate_decl (tree d, int defer_ok,
template from within the body of another. */
saved_local_specializations = local_specializations;
- /* Set up the list of local specializations. */
- local_specializations = new hash_map<tree, tree>;
+ /* Set up the list of local specializations, copying the current
+ list if there is one. */
+ if (local_specializations)
+ local_specializations
+ = new hash_map<tree, tree> (*local_specializations);
+ else
+ local_specializations = new hash_map<tree, tree>;
/* Set up context. */
if (DECL_OMP_DECLARE_REDUCTION_P (code_pattern)
diff --git a/gcc/hash-map.h b/gcc/hash-map.h
index b83708c..9b3d1e9 100644
--- a/gcc/hash-map.h
+++ b/gcc/hash-map.h
@@ -110,6 +110,11 @@ public:
bool gather_mem_stats = true CXX_MEM_STAT_INFO)
: m_table (n, ggc, gather_mem_stats, HASH_MAP_ORIGIN PASS_MEM_STAT) {}
+ hash_map (const hash_map &h, bool ggc = false,
+ bool gather_mem_stats = true CXX_MEM_STAT_INFO)
+ : m_table (h.m_table, ggc, gather_mem_stats,
+ HASH_MAP_ORIGIN PASS_MEM_STAT) {}
+
/* Create a hash_map in ggc memory. */
static hash_map *create_ggc (size_t size, bool gather_mem_stats = true
CXX_MEM_STAT_INFO)
diff --git a/gcc/hash-table.h b/gcc/hash-table.h
index 192be30..e3f9dbd 100644
--- a/gcc/hash-table.h
+++ b/gcc/hash-table.h
@@ -364,6 +364,10 @@ public:
explicit hash_table (size_t, bool ggc = false, bool gather_mem_stats = true,
mem_alloc_origin origin = HASH_TABLE_ORIGIN
CXX_MEM_STAT_INFO);
+ hash_table (const hash_table &, bool ggc = false,
+ bool gather_mem_stats = true,
+ mem_alloc_origin origin = HASH_TABLE_ORIGIN
+ CXX_MEM_STAT_INFO);
~hash_table ();
/* Create a hash_table in gc memory. */
@@ -580,6 +584,34 @@ hash_table<Descriptor, Allocator>::hash_table (size_t size, bool ggc, bool
}
template<typename Descriptor, template<typename Type> class Allocator>
+hash_table<Descriptor, Allocator>::hash_table (const hash_table &h, bool ggc,
+ bool gather_mem_stats,
+ mem_alloc_origin origin
+ MEM_STAT_DECL) :
+ m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
+ m_searches (0), m_collisions (0), m_ggc (ggc),
+ m_gather_mem_stats (gather_mem_stats)
+{
+ size_t size = h.m_size;
+
+ if (m_gather_mem_stats)
+ hash_table_usage.register_descriptor (this, origin, ggc
+ FINAL_PASS_MEM_STAT);
+
+ m_entries = alloc_entries (size PASS_MEM_STAT);
+ for (size_t i = 0; i < size; ++i)
+ {
+ value_type &entry = h.m_entries[i];
+ if (is_deleted (entry))
+ mark_deleted (m_entries[i]);
+ else if (!is_empty (entry))
+ m_entries[i] = entry;
+ }
+ m_size = size;
+ m_size_prime_index = h.m_size_prime_index;
+}
+
+template<typename Descriptor, template<typename Type> class Allocator>
hash_table<Descriptor, Allocator>::~hash_table ()
{
for (size_t i = m_size - 1; i < m_size; i--)
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
new file mode 100644
index 0000000..76b6b3f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
@@ -0,0 +1,9 @@
+// PR c++/68309
+// { dg-do compile { target c++11 } }
+
+template <class... Ts> void f(Ts...);
+template <class T> T g(T);
+template <typename... Ts> void print(Ts... args) {
+ [&] { f(g<decltype(args)>(args)...); }();
+}
+int main() { print(5.2); }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA (hash-*): PATCH for c++/68309
2015-12-11 19:06 ` Jason Merrill
@ 2015-12-14 8:51 ` Richard Biener
0 siblings, 0 replies; 6+ messages in thread
From: Richard Biener @ 2015-12-14 8:51 UTC (permalink / raw)
To: Jason Merrill
Cc: gcc-patches List, Jeffrey A Law, Richard Sandiford, Trevor Saunders
On Fri, Dec 11, 2015 at 8:05 PM, Jason Merrill <jason@redhat.com> wrote:
> On 12/11/2015 05:10 AM, Richard Biener wrote:
>>
>> On Thu, Dec 10, 2015 at 11:03 PM, Jason Merrill <jason@redhat.com> wrote:
>>>
>>> The C++ front end uses a temporary hash table to remember specializations
>>> of
>>> local variables during template instantiations. In a nested function
>>> such
>>> as a lambda or local class member function, we need to retain the
>>> elements
>>> from the enclosing function's local_specializations table; otherwise the
>>> testcase crashes because we don't find a local specialization for the
>>> non-captured use of 'args' in the decltype.
>>>
>>> This patch addresses that by making a copy of the enclosing
>>> local_specializations table if it exists; to enable that I've added copy
>>> constructors to hash_table and hash_map.
>>>
>>> Tested x86_64-pc-linux-gnu. OK for trunk?
>>
>>
>> I don't think you can copy the elements with memcpy they may be C++
>> classes
>> that are not copyable.
>
>
> True. Fixed thus:
>
>> + for (size_t i = 0; i < size; ++i)
>> + {
>> + value_type &entry = h.m_entries[i];
>> + if (is_deleted (entry))
>> + mark_deleted (m_entries[i]);
>> + else if (!is_empty (entry))
>> + m_entries[i] = entry;
>> + }
>
>
>> Also watch out for the bool gather_mem_stats = true
>> to bool gather_mem_stats = GATHER_STATISTICS change if that crosses your
>> change.
>
>
> OK.
>
>> I also think copying hash tables should be discouraged ;) I wonder if you
>> can get around the copying by adding a generation count (to easily
>> "backtrack")
>> instead.
>
>
> I considered having a chain of tables to check, to handle generations, but I
> figured that the tables in question were small enough (only containing local
> variables for a single function) that a simple copy was reasonable.
Looks good to me now. Needs adjustment to use GATHER_STATISTICS
as default-arg for gather_mem_stats now.
Thanks,
Richard.
> Jason
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA (hash-*): PATCH for c++/68309
2015-12-10 22:03 RFA (hash-*): PATCH for c++/68309 Jason Merrill
2015-12-11 10:11 ` Richard Biener
@ 2015-12-15 0:50 ` Trevor Saunders
2015-12-15 16:22 ` Jason Merrill
1 sibling, 1 reply; 6+ messages in thread
From: Trevor Saunders @ 2015-12-15 0:50 UTC (permalink / raw)
To: Jason Merrill
Cc: gcc-patches List, Jeffrey A Law, Richard Sandiford, Trevor Saunders
>
> + hash_map (const hash_map &h, bool ggc = false,
> + bool gather_mem_stats = true CXX_MEM_STAT_INFO)
sorry about the late response, but wouldn't it be better to make this
and the hash_table constructor explicit? Its probably less important
than other constructors, but is there a reasonable use for taking or
return them by value?
Trev
> + : m_table (h.m_table, ggc, gather_mem_stats,
> + HASH_MAP_ORIGIN PASS_MEM_STAT) {}
> +
> /* Create a hash_map in ggc memory. */
> static hash_map *create_ggc (size_t size, bool gather_mem_stats = true
> CXX_MEM_STAT_INFO)
> diff --git a/gcc/hash-table.h b/gcc/hash-table.h
> index 192be30..d172841 100644
> --- a/gcc/hash-table.h
> +++ b/gcc/hash-table.h
> @@ -364,6 +364,10 @@ public:
> explicit hash_table (size_t, bool ggc = false, bool gather_mem_stats = true,
> mem_alloc_origin origin = HASH_TABLE_ORIGIN
> CXX_MEM_STAT_INFO);
> + hash_table (const hash_table &, bool ggc = false,
> + bool gather_mem_stats = true,
> + mem_alloc_origin origin = HASH_TABLE_ORIGIN
> + CXX_MEM_STAT_INFO);
> ~hash_table ();
>
> /* Create a hash_table in gc memory. */
> @@ -580,6 +584,27 @@ hash_table<Descriptor, Allocator>::hash_table (size_t size, bool ggc, bool
> }
>
> template<typename Descriptor, template<typename Type> class Allocator>
> +hash_table<Descriptor, Allocator>::hash_table (const hash_table &h, bool ggc,
> + bool gather_mem_stats,
> + mem_alloc_origin origin
> + MEM_STAT_DECL) :
> + m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
> + m_searches (0), m_collisions (0),
> + m_ggc (ggc), m_gather_mem_stats (gather_mem_stats)
> +{
> + size_t size = h.m_size;
> +
> + if (m_gather_mem_stats)
> + hash_table_usage.register_descriptor (this, origin, ggc
> + FINAL_PASS_MEM_STAT);
> +
> + m_entries = alloc_entries (size PASS_MEM_STAT);
> + memcpy (m_entries, h.m_entries, size * sizeof (value_type));
> + m_size = size;
> + m_size_prime_index = h.m_size_prime_index;
> +}
> +
> +template<typename Descriptor, template<typename Type> class Allocator>
> hash_table<Descriptor, Allocator>::~hash_table ()
> {
> for (size_t i = m_size - 1; i < m_size; i--)
> diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
> new file mode 100644
> index 0000000..76b6b3f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-variadic3.C
> @@ -0,0 +1,9 @@
> +// PR c++/68309
> +// { dg-do compile { target c++11 } }
> +
> +template <class... Ts> void f(Ts...);
> +template <class T> T g(T);
> +template <typename... Ts> void print(Ts... args) {
> + [&] { f(g<decltype(args)>(args)...); }();
> +}
> +int main() { print(5.2); }
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: RFA (hash-*): PATCH for c++/68309
2015-12-15 0:50 ` Trevor Saunders
@ 2015-12-15 16:22 ` Jason Merrill
0 siblings, 0 replies; 6+ messages in thread
From: Jason Merrill @ 2015-12-15 16:22 UTC (permalink / raw)
To: Trevor Saunders
Cc: gcc-patches List, Jeffrey A Law, Richard Sandiford, Trevor Saunders
On 12/14/2015 07:49 PM, Trevor Saunders wrote:
>>
>> + hash_map (const hash_map &h, bool ggc = false,
>> + bool gather_mem_stats = true CXX_MEM_STAT_INFO)
>
> sorry about the late response, but wouldn't it be better to make this
> and the hash_table constructor explicit? Its probably less important
> than other constructors, but is there a reasonable use for taking or
> return them by value?
Makes sense; done.
Jason
^ permalink raw reply [flat|nested] 6+ messages in thread
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2015-12-10 22:03 RFA (hash-*): PATCH for c++/68309 Jason Merrill
2015-12-11 10:11 ` Richard Biener
2015-12-11 19:06 ` Jason Merrill
2015-12-14 8:51 ` Richard Biener
2015-12-15 0:50 ` Trevor Saunders
2015-12-15 16:22 ` Jason Merrill
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