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nvptx: In offloading compilation, special-case certain host-setup symbol aliases [PR101544]

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Namely, use PTX '.alias' even for (default) '-mno-alias' if the host made the
C++ "base and complete [cd]tor aliases".

	PR target/101544
	gcc/
	* config/nvptx/nvptx.cc (nvptx_asm_output_def_from_decls)
	[ACCEL_COMPILER]: Special-case certain host-setup symbol aliases.
	* varasm.cc (do_assemble_alias) [ACCEL_COMPILER]: Adjust.
This commit is contained in:
Thomas Schwinge 2025-03-20 14:21:26 +01:00
parent 5450afcfb7
commit 65b31b3fff
2 changed files with 33 additions and 2 deletions
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28
gcc/config/nvptx/nvptx.cc
View file

@ -245,7 +245,7 @@ default_ptx_version_option (void)
warp convergence. */
res = MAX (res, PTX_VERSION_6_0);
/* Pick at least 6.3. */
/* Pick at least 6.3, to enable PTX '.alias'. */
res = MAX (res, PTX_VERSION_6_3);
/* For sm_52+, pick at least 7.3, to enable PTX 'alloca'. */
@ -7713,6 +7713,30 @@ nvptx_asm_output_def_from_decls (FILE *stream, tree name,
{
if (nvptx_alias == 0 || !TARGET_PTX_6_3)
{
/* Symbol aliases are not supported here. */
#ifdef ACCEL_COMPILER
if (DECL_CXX_CONSTRUCTOR_P (name)
|| DECL_CXX_DESTRUCTOR_P (name))
{
/* ..., but symbol aliases are supported and used in the host system,
via 'gcc/cp/optimize.cc:can_alias_cdtor'. */
gcc_assert (!lookup_attribute ("weak", DECL_ATTRIBUTES (name)));
gcc_assert (TREE_CODE (name) == FUNCTION_DECL);
/* In this specific case, use PTX '.alias', if available, even for
(default) '-mno-alias'. */
if (TARGET_PTX_6_3)
{
DECL_ATTRIBUTES (name)
= tree_cons (get_identifier ("symbol alias handled"),
NULL_TREE, DECL_ATTRIBUTES (name));
goto emit_ptx_alias;
}
}
#endif
/* Copied from assemble_alias. */
error_at (DECL_SOURCE_LOCATION (name),
"alias definitions not supported in this configuration");
@ -7744,6 +7768,8 @@ nvptx_asm_output_def_from_decls (FILE *stream, tree name,
return;
}
emit_ptx_alias:
cgraph_node *cnode = cgraph_node::get (name);
if (!cnode->referred_to_p ())
/* Prevent "Internal error: reference to deleted section". */

7
gcc/varasm.cc
View file

@ -6525,7 +6525,12 @@ do_assemble_alias (tree decl, tree target)
IDENTIFIER_POINTER (target));
# endif
/* If symbol aliases aren't actually supported... */
if (!TARGET_SUPPORTS_ALIASES)
if (!TARGET_SUPPORTS_ALIASES
# ifdef ACCEL_COMPILER
/* ..., and unless special-cased... */
&& !lookup_attribute ("symbol alias handled", DECL_ATTRIBUTES (decl))
# endif
)
/* ..., 'ASM_OUTPUT_DEF{,_FROM_DECLS}' better have raised an error. */
gcc_checking_assert (seen_error ());
#elif defined (ASM_OUTPUT_WEAK_ALIAS) || defined (ASM_WEAKEN_DECL)