Hi!
On the following testcase we ICE, because the underlying artificial decls
have NULL DECL_NAME (intentional), thus mangling is not able to figure out
what to do. This patch attempts to follow the
http://sourcerytools.com/pipermail/cxx-abi-dev/2016-August/002951.html
proposal (and for error recovery just uses <decomp> in order not to ICE).
Not really sure about ABI tags though.
I guess one can specify abi tag on the whole decomposition, perhaps
__attribute__((abi_tag ("foobar"))) auto [ a, b ] = A ();
And/or there could be ABI tags on the type of the artifical decl.
What about ABI tags on the types that the decomposition resolved to
(say if std::tuple* is involved)? Shall all ABI tags go at the end
of the whole decomp decl, or shall the individual source names have their
ABI tags attached after them?
What about the std::tuple* case where the standalone vars exist too,
shall e.g. abi_tag attributes be copied from the decomp var to those?
Any other attributes to copy over (e.g. unused comes to mind).
In any case, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk (and the rest would be resolved incrementally)?
2016-11-15 Jakub Jelinek <ja...@redhat.com>
* decl.c (cp_finish_decomp): For DECL_NAMESPACE_SCOPE_P decl,
set DECL_ASSEMBLER_NAME.
* parser.c (cp_parser_decomposition_declaration): Likewise
if returning error_mark_node.
* mangle.c (mangle_decomp): New function.
* cp-tree.h (mangle_decomp): New declaration.
* g++.dg/cpp1z/decomp12.C: New test.
--- gcc/cp/decl.c.jj 2016-11-15 09:57:00.000000000 +0100
+++ gcc/cp/decl.c 2016-11-15 12:16:41.230596777 +0100
@@ -7301,7 +7301,6 @@ get_tuple_decomp_init (tree decl, unsign
void
cp_finish_decomp (tree decl, tree first, unsigned int count)
{
- location_t loc = DECL_SOURCE_LOCATION (decl);
if (error_operand_p (decl))
{
error_out:
@@ -7315,9 +7314,12 @@ cp_finish_decomp (tree decl, tree first,
}
first = DECL_CHAIN (first);
}
+ if (DECL_P (decl) && DECL_NAMESPACE_SCOPE_P (decl))
+ SET_DECL_ASSEMBLER_NAME (decl, get_identifier ("<decomp>"));
return;
}
+ location_t loc = DECL_SOURCE_LOCATION (decl);
if (type_dependent_expression_p (decl)
/* This happens for range for when not in templates.
Still add the DECL_VALUE_EXPRs for later processing. */
@@ -7530,6 +7532,8 @@ cp_finish_decomp (tree decl, tree first,
i++;
}
}
+ if (DECL_NAMESPACE_SCOPE_P (decl))
+ SET_DECL_ASSEMBLER_NAME (decl, mangle_decomp (decl, v));
}
/* Returns a declaration for a VAR_DECL as if:
--- gcc/cp/parser.c.jj 2016-11-15 10:37:56.000000000 +0100
+++ gcc/cp/parser.c 2016-11-15 12:16:26.361784744 +0100
@@ -12944,6 +12944,7 @@ cp_parser_decomposition_declaration (cp_
tree decl = start_decl (declarator, decl_specifiers, SD_INITIALIZED,
NULL_TREE, decl_specifiers->attributes,
&pushed_scope);
+ tree orig_decl = decl;
unsigned int i;
cp_expr e;
@@ -13020,6 +13021,12 @@ cp_parser_decomposition_declaration (cp_
if (pushed_scope)
pop_scope (pushed_scope);
+ if (decl == error_mark_node && DECL_P (orig_decl))
+ {
+ if (DECL_NAMESPACE_SCOPE_P (orig_decl))
+ SET_DECL_ASSEMBLER_NAME (orig_decl, get_identifier ("<decomp>"));
+ }
+
return decl;
}
--- gcc/cp/mangle.c.jj 2016-11-11 14:01:06.000000000 +0100
+++ gcc/cp/mangle.c 2016-11-15 11:48:58.345751857 +0100
@@ -3995,6 +3995,53 @@ mangle_vtt_for_type (const tree type)
return mangle_special_for_type (type, "TT");
}
+/* Returns an identifier for the mangled name of the decomposition
+ artificial variable DECL. DECLS is the vector of the VAR_DECLs
+ for the identifier-list. */
+
+tree
+mangle_decomp (const tree decl, vec<tree> &decls)
+{
+ gcc_assert (!type_dependent_expression_p (decl));
+
+ location_t saved_loc = input_location;
+ input_location = DECL_SOURCE_LOCATION (decl);
+
+ start_mangling (decl);
+ write_string ("_Z");
+
+ tree context = decl_mangling_context (decl);
+ gcc_assert (context != NULL_TREE);
+
+ bool nested = false;
+ if (DECL_NAMESPACE_STD_P (context))
+ write_string ("St");
+ else if (context != global_namespace)
+ {
+ nested = true;
+ write_char ('N');
+ write_prefix (decl_mangling_context (decl));
+ }
+
+ write_string ("DC");
+ unsigned int i;
+ tree d;
+ FOR_EACH_VEC_ELT (decls, i, d)
+ write_unqualified_name (d);
+ write_char ('E');
+
+ if (nested)
+ write_char ('E');
+
+ tree id = finish_mangling_get_identifier ();
+ if (DEBUG_MANGLE)
+ fprintf (stderr, "mangle_decomp = '%s'\n\n",
+ IDENTIFIER_POINTER (id));
+
+ input_location = saved_loc;
+ return id;
+}
+
/* Return an identifier for a construction vtable group. TYPE is
the most derived class in the hierarchy; BINFO is the base
subobject for which this construction vtable group will be used.
--- gcc/cp/cp-tree.h.jj 2016-11-15 09:57:00.000000000 +0100
+++ gcc/cp/cp-tree.h 2016-11-15 11:49:40.446215562 +0100
@@ -6868,6 +6868,7 @@ extern bool decl_tls_wrapper_p (tree);
extern tree mangle_ref_init_variable (tree);
extern char * get_mangled_vtable_map_var_name (tree);
extern bool mangle_return_type_p (tree);
+extern tree mangle_decomp (tree, vec<tree> &);
/* in dump.c */
extern bool cp_dump_tree (void *, tree);
--- gcc/testsuite/g++.dg/cpp1z/decomp12.C.jj 2016-11-15 12:42:02.319445610
+0100
+++ gcc/testsuite/g++.dg/cpp1z/decomp12.C 2016-11-15 12:43:09.147608099
+0100
@@ -0,0 +1,52 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "" }
+
+struct A { int i; long j; int k : 2; char l; } a;
+int c[2];
+struct B { template<int I> int &get () { return c[I]; } } b;
+namespace std {
+ template<typename T> struct tuple_size;
+ template<int, typename> struct tuple_element;
+}
+template<> struct std::tuple_size<B> { static constexpr int value = 2; };
+template<int I> struct std::tuple_element<I,B> { typedef int type; };
+
+auto [ aa, bb, cc, dd ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+// { dg-final { scan-assembler "_ZDC2aa2bb2cc2ddE" } }
+const auto & [ e, f, g, h ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+// { dg-final { scan-assembler "_ZDC1e1f1g1hE" } }
+auto [ ee, ff ] = b; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+// { dg-final { scan-assembler "_ZDC2ee2ffE" } }
+auto & [ gg, hh ] = b; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+// { dg-final { scan-assembler "_ZDC2gg2hhE" } }
+namespace N
+{
+ namespace M
+ {
+ auto [ i, j, k, l ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZN1N1MDC1i1j1k1lEE" } }
+ auto & [ m, n, o, ppp ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZN1N1MDC1m1n1o3pppEE" } }
+ auto [ ii, jj ] = b; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZN1N1MDC2ii2jjEE" } }
+ // { dg-final { scan-assembler "_ZN1N1M2iiE" } }
+ // { dg-final { scan-assembler "_ZN1N1M2jjE" } }
+ auto & [ mm, nn ] = b; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZN1N1MDC2mm2nnEE" } }
+ // { dg-final { scan-assembler "_ZN1N1M2mmE" } }
+ // { dg-final { scan-assembler "_ZN1N1M2nnE" } }
+ }
+}
+namespace std
+{
+ auto [ i2, j2, k2, l2 ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZStDC2i22j22k22l2E" } }
+ auto [ vv, ww ] = b; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+ // { dg-final { scan-assembler "_ZStDC2vv2wwE" } }
+ // { dg-final { scan-assembler "_ZSt2vv" } }
+ // { dg-final { scan-assembler "_ZSt2ww" } }
+}
+namespace
+{
+ auto [ v, w, x, y ] = a; // { dg-warning "decomposition
declaration only available with" "" { target c++14_down } }
+}
Jakub
