Based on Paolo's comments I am dropping the changes to
baseline_symbols.txt. As far as minor version, I am bumping it up to
18. Assuming that this patch will be able to go in gcc 4.8 (with minor
version 18), I want to keep it at the same version in google/main and
google/gcc-4_6.
Bootstraps and no test regression. OK for google/main and
google/gcc-4_6 branches?
---------
011-12-17 Easwaran Raman <[email protected]>
* common.opt (fsized-delete): New option.
cp/ChangeLog.google-main:
2011-12-17 Easwaran Raman <[email protected]>
* decl.c (cxx_init_decl_processing): Specify a function that
takes a void* and size_t for DELETE_EXPR.
* call.c (build_op_delete_call): If fsized-delete is used, use
the variant that takes size_t as the second parameter except
when deleteting a pointer of type void *.
testsuite/ChangeLog.google-main:
2011-12-17 Easwaran Raman <[email protected]>
* g++.dg/other/sized-delete-1.C: New test.
libstdc++-v3/ChangeLog.google-main:
2011-12-17 Easwaran Raman <[email protected]>
* libsupc++/del_op.cc (delete): Define a new variant
void operator delete(void*, std::size_t).
* libsupc++/new (delete): Declare
void operator delete(void*, std::size_t) throw();
* testsuite/util/testsuite_abi.cc (check_version): Add new
known version GLIBCXX_3.4.18.
* config/abi/pre/gnu.ver: Add new symbol _ZdlPv[jmy] at version
GLIBCXX_3.4.18.
On Wed, Dec 14, 2011 at 3:31 AM, Paolo Carlini <[email protected]> wrote:
> Hi,
>
>> On Mon, Dec 12, 2011 at 12:41 PM, Paolo Carlini
>> <[email protected]> wrote:
>>>
>>> On 12/12/2011 09:37 PM, Easwaran Raman wrote:
>>>>
>>>> Thanks for the comments Paolo. I have attached the new patch. I have
>>>> bumped the version to 3.4.18
>>>
>>> You shouldn't: 4.7 is not out yet, thus no reason to increase the minor
>>> version beyond the current 17.
>>
>> Ok, I then don't understand your comment
>> "Note that backporting the patch as-is to 4_6-branch would be very
>> wrong in terms of ABI (in mainline we already have a 3.4.17)".
>> My original patch added the new symbol in version 3.4.17. Since we
>> don't want to add the symbol to 3.4.16 (if we have a situation where
>> the new runtime is not available when running a program compiled with
>> -fsized-delete) and you said I shouldn't be using 3.4.17, I assumed
>> I had to bump up the version.
>
> Note this is going to be an academic discussion, because it's too late for
> 4.7 anyway, and I'm not even sure it's conforming to add overloads like this
> for operators.
>
> Anyway.
>
> For 4.6 branch at this point the situation would be very difficult. We could
> have a small time window before 4.7 is out to move **all** its new symbols
> vs 4.6, currently in 3.4.17, to a new 3.4.18 and then we could bump 4.6 to
> 3.4.17. You see, after a minor is delivered you cannot add anything to it,
> and also you have the general requirement that the minor version is the
> minor ersion, thus irrespective whether we are talking about gcc4.6 or
> gcc4.7, a specific minor version number defines which symbols are exported.
> I hope now the issues are more clear.You must be always very careful.
>
>>>> and used _ZdlPv[jmy] in gnu.ver. I have
>>>> also added the symbol to baseline_symbols.txt of other targets.
>>>
>>> You should not, just read again what I wrote. And you don't have to
>>> believe
>>> me: just browse the libstdc++ ChangeLogs and see if somebody ever does
>>> that
>>> when the linker map is touched.
>>
>> Sorry, I again misunderstood this as well (and still don't have a good
>> picture). Is the part which adds _ZdlPv[jmy] in gnu.ver ok?
>
> Looks fine yes. But I didn't really check the letters. General rule of thumb
> when fiddling with linker scripts: double check what you are doing with a
> multilib system, like x86_64, at least you can catch errors when you are
> mistakenly not accounting for the 32-bit version of the symbols. In the case
> at issue, size_t can boil down be unsigned int, unsigned long, unsigned long
> long, make sure the pattern includes all three.
>
>> I added
>> that by mimicking the symbol _Znw[jmy] found in the same file. From
>> the log, it looks like the baseline_symbols.txt seems to be generated,
>> but I am not sure how that is to be done. For example, r145437 says a
>> bunch of these baseline_symbols.txt are regenerated, but I don't see
>> any other change from which this might be generated.
>
> General rule of thumb: normally, if you aren't a release manager, or a
> maintainer, **never** regenerate the baseline_symbols files. Just add
> symbols to the linker script, that is normally fine, doesn't break anything
> per se, adding is fine (subtracting/changing is not, of course).
>
> Paolo.
Index: libstdc++-v3/libsupc++/del_op.cc
===================================================================
--- libstdc++-v3/libsupc++/del_op.cc (revision 182251)
+++ libstdc++-v3/libsupc++/del_op.cc (working copy)
@@ -46,3 +46,11 @@ operator delete(void* ptr) throw ()
if (ptr)
std::free(ptr);
}
+
+_GLIBCXX_WEAK_DEFINITION void
+operator delete(void* ptr,
+ std::size_t bytes __attribute__((__unused__))) throw ()
+{
+ if (ptr)
+ std::free(ptr);
+}
Index: libstdc++-v3/libsupc++/new
===================================================================
--- libstdc++-v3/libsupc++/new (revision 182251)
+++ libstdc++-v3/libsupc++/new (working copy)
@@ -93,6 +93,7 @@ namespace std
void* operator new(std::size_t) throw (std::bad_alloc);
void* operator new[](std::size_t) throw (std::bad_alloc);
void operator delete(void*) throw();
+void operator delete(void*, std::size_t) throw();
void operator delete[](void*) throw();
void* operator new(std::size_t, const std::nothrow_t&) throw();
void* operator new[](std::size_t, const std::nothrow_t&) throw();
Index: libstdc++-v3/testsuite/util/testsuite_abi.cc
===================================================================
--- libstdc++-v3/testsuite/util/testsuite_abi.cc (revision 182251)
+++ libstdc++-v3/testsuite/util/testsuite_abi.cc (working copy)
@@ -195,6 +195,7 @@ check_version(symbol& test, bool added)
known_versions.push_back("GLIBCXX_3.4.15");
known_versions.push_back("GLIBCXX_3.4.16");
known_versions.push_back("GLIBCXX_3.4.17");
+ known_versions.push_back("GLIBCXX_3.4.18");
known_versions.push_back("GLIBCXX_LDBL_3.4");
known_versions.push_back("GLIBCXX_LDBL_3.4.7");
known_versions.push_back("GLIBCXX_LDBL_3.4.10");
@@ -561,4 +562,3 @@ demangle(const std::string& mangled)
}
return name;
}
-
Index: libstdc++-v3/config/abi/pre/gnu.ver
===================================================================
--- libstdc++-v3/config/abi/pre/gnu.ver (revision 182251)
+++ libstdc++-v3/config/abi/pre/gnu.ver (working copy)
@@ -1304,6 +1304,13 @@ GLIBCXX_3.4.17 {
} GLIBCXX_3.4.16;
+GLIBCXX_3.4.18 {
+
+ # operator delete(void*, , unsigned long)
+ _ZdlPv[jmy];
+
+} GLIBCXX_3.4.17;
+
# Symbols in the support library (libsupc++) have their own tag.
CXXABI_1.3 {
Index: gcc/testsuite/g++.dg/other/sized-delete-1.C
===================================================================
--- gcc/testsuite/g++.dg/other/sized-delete-1.C (revision 0)
+++ gcc/testsuite/g++.dg/other/sized-delete-1.C (revision 0)
@@ -0,0 +1,14 @@
+// { dg-do link}
+// { dg-options "-O -fsized-delete" }
+// { dg-final { scan-assembler "_ZdlPv\[mj\]" } }
+struct A
+{
+ int a[100];
+};
+
+int main(void)
+{
+ A *a = new A;
+ delete a;
+ return 0;
+}
Index: gcc/cp/decl.c
===================================================================
--- gcc/cp/decl.c (revision 182251)
+++ gcc/cp/decl.c (working copy)
@@ -3552,6 +3552,7 @@ cxx_init_decl_processing (void)
{
tree void_ftype;
tree void_ftype_ptr;
+ tree void_ftype_ptr_sizetype;
/* Create all the identifiers we need. */
initialize_predefined_identifiers ();
@@ -3613,8 +3614,14 @@ cxx_init_decl_processing (void)
void_ftype = build_function_type_list (void_type_node, NULL_TREE);
void_ftype_ptr = build_function_type_list (void_type_node,
ptr_type_node, NULL_TREE);
+ void_ftype_ptr_sizetype = build_function_type_list (void_type_node,
+ ptr_type_node,
+ size_type_node,
+ NULL_TREE);
void_ftype_ptr
= build_exception_variant (void_ftype_ptr, empty_except_spec);
+ void_ftype_ptr_sizetype
+ = build_exception_variant (void_ftype_ptr_sizetype, empty_except_spec);
/* C++ extensions */
@@ -3669,7 +3676,7 @@ cxx_init_decl_processing (void)
{
tree newattrs;
- tree newtype, deltype;
+ tree newtype, deltype, deltype2;
tree ptr_ftype_sizetype;
tree new_eh_spec;
@@ -3704,8 +3711,10 @@ cxx_init_decl_processing (void)
newtype = cp_build_type_attribute_variant (ptr_ftype_sizetype, newattrs);
newtype = build_exception_variant (newtype, new_eh_spec);
deltype = build_exception_variant (void_ftype_ptr, empty_except_spec);
+ deltype2 = build_exception_variant (void_ftype_ptr_sizetype, empty_except_spec);
push_cp_library_fn (NEW_EXPR, newtype);
push_cp_library_fn (VEC_NEW_EXPR, newtype);
+ push_cp_library_fn (DELETE_EXPR, deltype2);
global_delete_fndecl = push_cp_library_fn (DELETE_EXPR, deltype);
push_cp_library_fn (VEC_DELETE_EXPR, deltype);
Index: gcc/cp/call.c
===================================================================
--- gcc/cp/call.c (revision 182251)
+++ gcc/cp/call.c (working copy)
@@ -5408,8 +5408,22 @@ build_op_delete_call (enum tree_code code, tree ad
usual deallocation function."
So (void*) beats (void*, size_t). */
- if (FUNCTION_ARG_CHAIN (fn) == void_list_node)
- break;
+ /* If type is not void, pick (void*, size_t) version (which comes
+ first). */
+ if (!flag_sized_delete || TREE_CODE (type) == VOID_TYPE )
+ {
+ /* If -fsized-delete is not passed or if a void * is deleted,
+ prefer delete (void *) version. */
+ if (FUNCTION_ARG_CHAIN (fn) == void_list_node)
+ break;
+ }
+ else
+ {
+ /* If -fsized-delete is passed and it is not a void *,
+ prefer delete (void *, size_t) version. */
+ if (FUNCTION_ARG_CHAIN (fn) != void_list_node)
+ break;
+ }
}
}
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (revision 182251)
+++ gcc/common.opt (working copy)
@@ -1927,6 +1927,10 @@ fsingle-precision-constant
Common Report Var(flag_single_precision_constant) Optimization
Convert floating point constants to single precision constants
+fsized-delete
+Common Report Var(flag_sized_delete) Optimization
+Support delete operator with objetc's size as the second parameter.
+
fsplit-ivs-in-unroller
Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
Split lifetimes of induction variables when loops are unrolled
