Hi!
__cxa_atexit/__cxa_thread_atexit/__cxa_throw functions accept function
pointers to usually directly destructors rather than wrappers around
them.
Now, mingw ia32 uses implicitly __attribute__((thiscall)) calling
conventions for METHOD_TYPE (where the this pointer is passed in %ecx
register, the rest on the stack), so these functions use:
in config/os/mingw32/os_defines.h:
#if defined (__i386__)
#define _GLIBCXX_CDTOR_CALLABI __thiscall
#endif
in libsupc++/cxxabi.h
__cxa_atexit(void (_GLIBCXX_CDTOR_CALLABI *)(void*), void*, void*)
_GLIBCXX_NOTHROW;
__cxa_thread_atexit(void (_GLIBCXX_CDTOR_CALLABI *)(void*), void*, void *)
_GLIBCXX_NOTHROW;
__cxa_throw(void*, std::type_info*, void (_GLIBCXX_CDTOR_CALLABI *) (void *))
__attribute__((__noreturn__));
Now, mingw for some weird reason uses
#define TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT hook_bool_void_true
so it never actually uses __cxa_atexit, but does use __cxa_thread_atexit
and __cxa_throw. Recent changes for modules result in more detailed
__cxa_*atexit/__cxa_throw prototypes precreated by the compiler, and if
that happens and one also includes <cxxabi.h>, the compiler complains about
mismatches in the prototypes.
One thing is the missing thiscall attribute on the FUNCTION_TYPE, the
other problem is that all of atexit/__cxa_atexit/__cxa_thread_atexit
get function pointer types gets created by a single function,
get_atexit_fn_ptr_type (), which creates it depending on if atexit
or __cxa_atexit will be used as either void(*)(void) or void(*)(void *),
but when using atexit and __cxa_thread_atexit it uses the wrong function
type for __cxa_thread_atexit.
The following patch adds a target hook to add the thiscall attribute to the
function pointers, and splits the get_atexit_fn_ptr_type () function into
get_atexit_fn_ptr_type () and get_cxa_atexit_fn_ptr_type (), the former always
creates shared void(*)(void) type, the latter creates either
void(*)(void*) (on most targets) or void(__attribute__((thiscall))*)(void*)
(on mingw ia32). So that we don't waiste another GTY global tree for it,
because cleanup_type used for the same purpose for __cxa_throw should be
the same, the code changes it to use that type too.
In register_dtor_fn then based on the decision whether to use atexit,
__cxa_atexit or __cxa_thread_atexit it picks the right function pointer
type, and also if it decides to emit a __tcf_* wrapper for the cleanup,
uses that type for that wrapper so that it agrees on calling convention.
Bootstrapped/regtested on x86_64-linux and i686-linux and Liu Hao tested
it on mingw32, ok for trunk?
2024-05-09 Jakub Jelinek <ja...@redhat.com>
PR target/114968
gcc/
* target.def (use_atexit_for_cxa_atexit): Remove spurious space
from comment.
(adjust_cdtor_callabi_fntype): New cxx target hook.
* targhooks.h (default_cxx_adjust_cdtor_callabi_fntype): Declare.
* targhooks.cc (default_cxx_adjust_cdtor_callabi_fntype): New
function.
* doc/tm.texi.in (TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE): Add.
* doc/tm.texi: Regenerate.
* config/i386/i386.cc (ix86_cxx_adjust_cdtor_callabi_fntype): New
function.
(TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE): Redefine.
gcc/cp/
* cp-tree.h (atexit_fn_ptr_type_node, cleanup_type): Adjust macro
comments.
(get_cxa_atexit_fn_ptr_type): Declare.
* decl.cc (get_atexit_fn_ptr_type): Adjust function comment, only
build type for atexit argument.
(get_cxa_atexit_fn_ptr_type): New function.
(get_atexit_node): Call get_cxa_atexit_fn_ptr_type rather than
get_atexit_fn_ptr_type when using __cxa_atexit.
(get_thread_atexit_node): Call get_cxa_atexit_fn_ptr_type
rather than get_atexit_fn_ptr_type.
(start_cleanup_fn): Add fntype argument, don't call
get_atexit_fn_ptr_type for it.
(register_dtor_fn): Adjust start_cleanup_fn caller, use
get_cxa_atexit_fn_ptr_type rather than get_atexit_fn_ptr_type
when ob_parm is true.
* except.cc (build_throw): Use get_cxa_atexit_fn_ptr_type ().
--- gcc/target.def.jj 2024-05-07 21:28:46.554394913 +0200
+++ gcc/target.def 2024-05-08 11:19:39.290798568 +0200
@@ -6498,7 +6498,7 @@ is in effect. The default is to return
hook_bool_void_false)
/* Returns true if target may use atexit in the same manner as
- __cxa_atexit to register static destructors. */
+ __cxa_atexit to register static destructors. */
DEFHOOK
(use_atexit_for_cxa_atexit,
"This hook returns true if the target @code{atexit} function can be used\n\
@@ -6509,6 +6509,17 @@ unloaded. The default is to return false
bool, (void),
hook_bool_void_false)
+/* Returns modified FUNCTION_TYPE for cdtor callabi. */
+DEFHOOK
+(adjust_cdtor_callabi_fntype,
+ "This hook returns a possibly modified @code{FUNCTION_TYPE} for arguments\n\
+to @code{__cxa_atexit}, @code{__cxa_thread_atexit} or @code{__cxa_throw}\n\
+function pointers. ABIs like mingw32 require special attributes to be added\n\
+to function types pointed to by arguments of these functions.\n\
+The default is to return the passed argument unmodified.",
+ tree, (tree fntype),
+ default_cxx_adjust_cdtor_callabi_fntype)
+
DEFHOOK
(adjust_class_at_definition,
"@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\n\
--- gcc/targhooks.h.jj 2024-05-07 21:28:46.554394913 +0200
+++ gcc/targhooks.h 2024-05-08 11:19:39.290798568 +0200
@@ -65,6 +65,7 @@ extern machine_mode default_mode_for_suf
extern tree default_cxx_guard_type (void);
extern tree default_cxx_get_cookie_size (tree);
+extern tree default_cxx_adjust_cdtor_callabi_fntype (tree);
extern bool hook_pass_by_reference_must_pass_in_stack
(cumulative_args_t, const function_arg_info &);
--- gcc/targhooks.cc.jj 2024-05-07 21:28:46.554394913 +0200
+++ gcc/targhooks.cc 2024-05-08 11:19:39.290798568 +0200
@@ -329,6 +329,14 @@ default_cxx_get_cookie_size (tree type)
return cookie_size;
}
+/* Returns modified FUNCTION_TYPE for cdtor callabi. */
+
+tree
+default_cxx_adjust_cdtor_callabi_fntype (tree fntype)
+{
+ return fntype;
+}
+
/* Return true if a parameter must be passed by reference. This version
of the TARGET_PASS_BY_REFERENCE hook uses just MUST_PASS_IN_STACK. */
--- gcc/doc/tm.texi.in.jj 2024-05-07 21:28:46.553394927 +0200
+++ gcc/doc/tm.texi.in 2024-05-08 11:19:39.291798555 +0200
@@ -7223,6 +7223,8 @@ floating-point support; they are not inc
@hook TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT
+@hook TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE
+
@hook TARGET_CXX_ADJUST_CLASS_AT_DEFINITION
@hook TARGET_CXX_DECL_MANGLING_CONTEXT
--- gcc/doc/tm.texi.jj 2024-05-07 21:28:46.523395332 +0200
+++ gcc/doc/tm.texi 2024-05-08 11:19:39.293798528 +0200
@@ -11117,6 +11117,14 @@ shared libraries are run in the correct
unloaded. The default is to return false.
@end deftypefn
+@deftypefn {Target Hook} tree TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE (tree
@var{fntype})
+This hook returns a possibly modified @code{FUNCTION_TYPE} for arguments
+to @code{__cxa_atexit}, @code{__cxa_thread_atexit} or @code{__cxa_throw}
+function pointers. ABIs like mingw32 require special attributes to be added
+to function types pointed to by arguments of these functions.
+The default is to return the passed argument unmodified.
+@end deftypefn
+
@deftypefn {Target Hook} void TARGET_CXX_ADJUST_CLASS_AT_DEFINITION (tree
@var{type})
@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just
been defined. Use this hook to make adjustments to the class (eg, tweak
--- gcc/config/i386/i386.cc.jj 2024-05-08 10:16:53.959824814 +0200
+++ gcc/config/i386/i386.cc 2024-05-08 11:19:39.288798595 +0200
@@ -25799,6 +25799,20 @@ ix86_bitint_type_info (int n, struct bit
return true;
}
+/* Returns modified FUNCTION_TYPE for cdtor callabi. */
+tree
+ix86_cxx_adjust_cdtor_callabi_fntype (tree fntype)
+{
+ if (TARGET_64BIT
+ || TARGET_RTD
+ || ix86_function_type_abi (fntype) != MS_ABI)
+ return fntype;
+ /* For 32-bit MS ABI add thiscall attribute. */
+ tree attribs = tree_cons (get_identifier ("thiscall"), NULL_TREE,
+ TYPE_ATTRIBUTES (fntype));
+ return build_type_attribute_variant (fntype, attribs);
+}
+
/* Implement PUSH_ROUNDING. On 386, we have pushw instruction that
decrements by exactly 2 no matter what the position was, there is no pushb.
@@ -26410,6 +26424,8 @@ static const scoped_attribute_specs *con
#define TARGET_C_EXCESS_PRECISION ix86_get_excess_precision
#undef TARGET_C_BITINT_TYPE_INFO
#define TARGET_C_BITINT_TYPE_INFO ix86_bitint_type_info
+#undef TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE
+#define TARGET_CXX_ADJUST_CDTOR_CALLABI_FNTYPE
ix86_cxx_adjust_cdtor_callabi_fntype
#undef TARGET_PROMOTE_PROTOTYPES
#define TARGET_PROMOTE_PROTOTYPES hook_bool_const_tree_true
#undef TARGET_PUSH_ARGUMENT
--- gcc/cp/cp-tree.h.jj 2024-05-07 08:47:36.092835331 +0200
+++ gcc/cp/cp-tree.h 2024-05-08 11:46:46.767087686 +0200
@@ -368,8 +368,7 @@ extern GTY(()) tree cp_global_trees[CPTI
#define throw_fn cp_global_trees[CPTI_THROW_FN]
#define rethrow_fn cp_global_trees[CPTI_RETHROW_FN]
-/* The type of the function-pointer argument to "__cxa_atexit" (or
- "std::atexit", if "__cxa_atexit" is not being used). */
+/* The type of the function-pointer argument to "std::atexit". */
#define atexit_fn_ptr_type_node
cp_global_trees[CPTI_ATEXIT_FN_PTR_TYPE]
/* A pointer to `std::atexit'. */
@@ -384,7 +383,8 @@ extern GTY(()) tree cp_global_trees[CPTI
/* The declaration of the dynamic_cast runtime. */
#define dynamic_cast_node cp_global_trees[CPTI_DCAST]
-/* The type of a destructor. */
+/* The type of a destructor, passed to __cxa_atexit, __cxa_thread_atexit
+ or __cxa_throw. */
#define cleanup_type cp_global_trees[CPTI_CLEANUP_TYPE]
/* The type of the vtt parameter passed to subobject constructors and
@@ -7067,6 +7067,7 @@ extern tree check_default_argument (tre
extern int wrapup_namespace_globals ();
extern tree create_implicit_typedef (tree, tree);
extern int local_variable_p (const_tree);
+extern tree get_cxa_atexit_fn_ptr_type ();
extern tree register_dtor_fn (tree);
extern tmpl_spec_kind current_tmpl_spec_kind (int);
extern tree cxx_builtin_function (tree decl);
--- gcc/cp/decl.cc.jj 2024-05-07 21:28:50.230345231 +0200
+++ gcc/cp/decl.cc 2024-05-08 11:57:57.655143259 +0200
@@ -93,7 +93,7 @@ static void record_key_method_defined (t
static tree create_array_type_for_decl (tree, tree, tree, location_t);
static tree get_atexit_node (void);
static tree get_dso_handle_node (void);
-static tree start_cleanup_fn (void);
+static tree start_cleanup_fn (tree);
static void end_cleanup_fn (void);
static tree cp_make_fname_decl (location_t, tree, int);
static void initialize_predefined_identifiers (void);
@@ -9678,34 +9678,39 @@ declare_global_var (tree name, tree type
return decl;
}
-/* Returns the type for the argument to "__cxa_atexit" (or "atexit",
- if "__cxa_atexit" is not being used) corresponding to the function
+/* Returns the type for the argument to "atexit" corresponding to the function
to be called when the program exits. */
static tree
-get_atexit_fn_ptr_type (void)
+get_atexit_fn_ptr_type ()
{
- tree fn_type;
-
if (!atexit_fn_ptr_type_node)
{
- tree arg_type;
- if (flag_use_cxa_atexit
- && !targetm.cxx.use_atexit_for_cxa_atexit ())
- /* The parameter to "__cxa_atexit" is "void (*)(void *)". */
- arg_type = ptr_type_node;
- else
- /* The parameter to "atexit" is "void (*)(void)". */
- arg_type = NULL_TREE;
-
- fn_type = build_function_type_list (void_type_node,
- arg_type, NULL_TREE);
+ tree fn_type = build_function_type_list (void_type_node, NULL_TREE);
atexit_fn_ptr_type_node = build_pointer_type (fn_type);
}
return atexit_fn_ptr_type_node;
}
+/* Returns the type for the argument to "__cxa_atexit", "__cxa_thread_atexit"
+ or "__cxa_throw" corresponding to the destructor to be called when the
+ program exits. */
+
+tree
+get_cxa_atexit_fn_ptr_type ()
+{
+ if (!cleanup_type)
+ {
+ tree fntype = build_function_type_list (void_type_node,
+ ptr_type_node, NULL_TREE);
+ fntype = targetm.cxx.adjust_cdtor_callabi_fntype (fntype);
+ cleanup_type = build_pointer_type (fntype);
+ }
+
+ return cleanup_type;
+}
+
/* Returns a pointer to the `atexit' function. Note that if
FLAG_USE_CXA_ATEXIT is nonzero, then this will actually be the new
`__cxa_atexit' function specified in the IA64 C++ ABI. */
@@ -9736,7 +9741,7 @@ get_atexit_node (void)
use_aeabi_atexit = targetm.cxx.use_aeabi_atexit ();
/* First, build the pointer-to-function type for the first
argument. */
- fn_ptr_type = get_atexit_fn_ptr_type ();
+ fn_ptr_type = get_cxa_atexit_fn_ptr_type ();
/* Then, build the rest of the argument types. */
argtype2 = ptr_type_node;
if (use_aeabi_atexit)
@@ -9819,7 +9824,7 @@ get_thread_atexit_node (void)
int __cxa_thread_atexit (void (*)(void *), void *, void *) */
tree fn_type = build_function_type_list (integer_type_node,
- get_atexit_fn_ptr_type (),
+ get_cxa_atexit_fn_ptr_type (),
ptr_type_node, ptr_type_node,
NULL_TREE);
@@ -9866,7 +9871,7 @@ get_dso_handle_node (void)
static GTY(()) int start_cleanup_cnt;
static tree
-start_cleanup_fn (void)
+start_cleanup_fn (tree fntype)
{
char name[32];
@@ -9878,7 +9883,6 @@ start_cleanup_fn (void)
/* Build the name of the function. */
sprintf (name, "__tcf_%d", start_cleanup_cnt++);
/* Build the function declaration. */
- tree fntype = TREE_TYPE (get_atexit_fn_ptr_type ());
tree fndecl = build_lang_decl (FUNCTION_DECL, get_identifier (name), fntype);
DECL_CONTEXT (fndecl) = FROB_CONTEXT (current_namespace);
/* It's a function with internal linkage, generated by the
@@ -9968,8 +9972,10 @@ register_dtor_fn (tree decl)
build_cleanup (decl);
/* Now start the function. */
- cleanup = start_cleanup_fn ();
-
+ cleanup = start_cleanup_fn (TREE_TYPE (ob_parm
+ ? get_cxa_atexit_fn_ptr_type ()
+ : get_atexit_fn_ptr_type ()));
+
/* Now, recompute the cleanup. It may contain SAVE_EXPRs that refer
to the original function, rather than the anonymous one. That
will make the back end think that nested functions are in use,
@@ -9998,7 +10004,8 @@ register_dtor_fn (tree decl)
{
/* We must convert CLEANUP to the type that "__cxa_atexit"
expects. */
- cleanup = build_nop (get_atexit_fn_ptr_type (), cleanup);
+ cleanup = build_nop (ob_parm ? get_cxa_atexit_fn_ptr_type ()
+ : get_atexit_fn_ptr_type (), cleanup);
/* "__cxa_atexit" will pass the address of DECL to the
cleanup function. */
mark_used (decl);
--- gcc/cp/except.cc.jj 2024-05-07 21:28:46.520395373 +0200
+++ gcc/cp/except.cc 2024-05-08 11:47:26.397559706 +0200
@@ -645,11 +645,7 @@ build_throw (location_t loc, tree exp, t
/* The CLEANUP_TYPE is the internal type of a destructor. */
if (!cleanup_type)
- {
- tree tmp = build_function_type_list (void_type_node,
- ptr_type_node, NULL_TREE);
- cleanup_type = build_pointer_type (tmp);
- }
+ cleanup_type = get_cxa_atexit_fn_ptr_type ();
if (!throw_fn)
{
Jakub
