void
use_thunk (tree thunk_fndecl, bool emit_p)
{
tree a, t, function, alias;
tree virtual_offset;
HOST_WIDE_INT fixed_offset, virtual_value;
bool this_adjusting = DECL_THIS_THUNK_P (thunk_fndecl);
/* We should have called finish_thunk to give it a name. */
gcc_assert (DECL_NAME (thunk_fndecl));
/* We should never be using an alias, always refer to the
aliased thunk. */
gcc_assert (!THUNK_ALIAS (thunk_fndecl));
if (TREE_ASM_WRITTEN (thunk_fndecl))
return;
function = THUNK_TARGET (thunk_fndecl);
if (DECL_RESULT (thunk_fndecl))
/* We already turned this thunk into an ordinary function.
There's no need to process this thunk again. */
return;
if (DECL_THUNK_P (function))
/* The target is itself a thunk, process it now. */
use_thunk (function, emit_p);
/* Thunks are always addressable; they only appear in vtables. */
TREE_ADDRESSABLE (thunk_fndecl) = 1;
/* Figure out what function is being thunked to. It's referenced in
this translation unit. */
TREE_ADDRESSABLE (function) = 1;
mark_used (function);
if (!emit_p)
return;
if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function))
alias = make_alias_for_thunk (function);
else
alias = function;
fixed_offset = THUNK_FIXED_OFFSET (thunk_fndecl);
virtual_offset = THUNK_VIRTUAL_OFFSET (thunk_fndecl);
if (virtual_offset)
{
if (!this_adjusting)
virtual_offset = BINFO_VPTR_FIELD (virtual_offset);
virtual_value = tree_low_cst (virtual_offset, /*pos=*/0);
gcc_assert (virtual_value);
}
else
virtual_value = 0;
/* And, if we need to emit the thunk, it's used. */
mark_used (thunk_fndecl);
/* This thunk is actually defined. */
DECL_EXTERNAL (thunk_fndecl) = 0;
/* The linkage of the function may have changed. FIXME in linkage
rewrite. */
TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function);
DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function);
DECL_VISIBILITY_SPECIFIED (thunk_fndecl)
= DECL_VISIBILITY_SPECIFIED (function);
if (DECL_ONE_ONLY (function))
make_decl_one_only (thunk_fndecl);
if (flag_syntax_only)
{
TREE_ASM_WRITTEN (thunk_fndecl) = 1;
return;
}
push_to_top_level ();
if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function)
&& targetm.have_named_sections)
{
resolve_unique_section (function, 0, flag_function_sections);
if (DECL_SECTION_NAME (function) != NULL && DECL_ONE_ONLY (function))
{
resolve_unique_section (thunk_fndecl, 0, flag_function_sections);
/* Output the thunk into the same section as function. */
DECL_SECTION_NAME (thunk_fndecl) = DECL_SECTION_NAME (function);
}
}
/* The back-end expects DECL_INITIAL to contain a BLOCK, so we
create one. */
DECL_INITIAL (thunk_fndecl) = make_node (BLOCK);
/* Set up cloned argument trees for the thunk. */
t = NULL_TREE;
for (a = DECL_ARGUMENTS (function); a; a = TREE_CHAIN (a))
{
tree x = copy_node (a);
TREE_CHAIN (x) = t;
DECL_CONTEXT (x) = thunk_fndecl;
SET_DECL_RTL (x, NULL_RTX);
DECL_HAS_VALUE_EXPR_P (x) = 0;
t = x;
}
a = nreverse (t);
DECL_ARGUMENTS (thunk_fndecl) = a;
BLOCK_VARS (DECL_INITIAL (thunk_fndecl)) = a;
if (this_adjusting
&& targetm.asm_out.can_output_mi_thunk (thunk_fndecl, fixed_offset,
virtual_value, alias))
{
const char *fnname;
current_function_decl = thunk_fndecl;
DECL_RESULT (thunk_fndecl)
= build_decl (RESULT_DECL, 0, integer_type_node);
fnname = XSTR (XEXP (DECL_RTL (thunk_fndecl), 0), 0);
init_function_start (thunk_fndecl);
current_function_is_thunk = 1;
assemble_start_function (thunk_fndecl, fnname);
targetm.asm_out.output_mi_thunk (asm_out_file, thunk_fndecl,
fixed_offset, virtual_value, alias);
assemble_end_function (thunk_fndecl, fnname);
init_insn_lengths ();
current_function_decl = 0;
cfun = 0;
TREE_ASM_WRITTEN (thunk_fndecl) = 1;
}
else
{
/* If this is a covariant thunk, or we don't have the necessary
code for efficient thunks, generate a thunk function that
just makes a call to the real function. Unfortunately, this
doesn't work for varargs. */
if (varargs_function_p (function))
error ("generic thunk code fails for method %q#D which uses %<...%>",
function);
DECL_RESULT (thunk_fndecl) = NULL_TREE;
start_preparsed_function (thunk_fndecl, NULL_TREE, SF_PRE_PARSED);
/* We don't bother with a body block for thunks. */
/* There's no need to check accessibility inside the thunk body. */
push_deferring_access_checks (dk_no_check);
t = a;
if (this_adjusting)
t = thunk_adjust (t, /*this_adjusting=*/1,
fixed_offset, virtual_offset);
/* Build up the call to the real function. */
t = tree_cons (NULL_TREE, t, NULL_TREE);
for (a = TREE_CHAIN (a); a; a = TREE_CHAIN (a))
t = tree_cons (NULL_TREE, a, t);
t = nreverse (t);
t = build_call (alias, t);
CALL_FROM_THUNK_P (t) = 1;
if (VOID_TYPE_P (TREE_TYPE (t)))
finish_expr_stmt (t);
else
{
if (!this_adjusting)
{
tree cond = NULL_TREE;
if (TREE_CODE (TREE_TYPE (t)) == POINTER_TYPE)
{
/* If the return type is a pointer, we need to
protect against NULL. We know there will be an
adjustment, because that's why we're emitting a
thunk. */
t = save_expr (t);
cond = cp_convert (boolean_type_node, t);
}
t = thunk_adjust (t, /*this_adjusting=*/0,
fixed_offset, virtual_offset);
if (cond)
t = build3 (COND_EXPR, TREE_TYPE (t), cond, t,
cp_convert (TREE_TYPE (t), integer_zero_node));
}
if (IS_AGGR_TYPE (TREE_TYPE (t)))
t = build_cplus_new (TREE_TYPE (t), t);
finish_return_stmt (t);
}
/* Since we want to emit the thunk, we explicitly mark its name as
referenced. */
mark_decl_referenced (thunk_fndecl);
/* But we don't want debugging information about it. */
DECL_IGNORED_P (thunk_fndecl) = 1;
/* Re-enable access control. */
pop_deferring_access_checks ();
thunk_fndecl = finish_function (0);
tree_lowering_passes (thunk_fndecl);
expand_body (thunk_fndecl);
}
pop_from_top_level ();
}
void
use_thunk (tree thunk_fndecl, bool emit_p)
{
tree a, t, function, alias;
tree virtual_offset;
HOST_WIDE_INT fixed_offset, virtual_value;
bool this_adjusting = DECL_THIS_THUNK_P (thunk_fndecl);
/* We should have called finish_thunk to give it a name. */
gcc_assert (DECL_NAME (thunk_fndecl));
/* We should never be using an alias, always refer to the
aliased thunk. */
gcc_assert (!THUNK_ALIAS (thunk_fndecl));
if (TREE_ASM_WRITTEN (thunk_fndecl))
return;
function = THUNK_TARGET (thunk_fndecl);
if (DECL_RESULT (thunk_fndecl))
/* We already turned this thunk into an ordinary function.
There's no need to process this thunk again. */
return;
if (DECL_THUNK_P (function))
/* The target is itself a thunk, process it now. */
use_thunk (function, emit_p);
/* Thunks are always addressable; they only appear in vtables. */
TREE_ADDRESSABLE (thunk_fndecl) = 1;
/* Figure out what function is being thunked to. It's referenced in
this translation unit. */
TREE_ADDRESSABLE (function) = 1;
mark_used (function);
if (!emit_p)
return;
if (0 && TARGET_USE_LOCAL_THUNK_ALIAS_P (function))
alias = make_alias_for_thunk (function);
else
alias = function;
fixed_offset = THUNK_FIXED_OFFSET (thunk_fndecl);
virtual_offset = THUNK_VIRTUAL_OFFSET (thunk_fndecl);
if (virtual_offset)
{
if (!this_adjusting)
virtual_offset = BINFO_VPTR_FIELD (virtual_offset);
virtual_value = tree_low_cst (virtual_offset, /*pos=*/0);
gcc_assert (virtual_value);
}
else
virtual_value = 0;
/* And, if we need to emit the thunk, it's used. */
mark_used (thunk_fndecl);
/* This thunk is actually defined. */
DECL_EXTERNAL (thunk_fndecl) = 0;
/* The linkage of the function may have changed. FIXME in linkage
rewrite. */
TREE_PUBLIC (thunk_fndecl) = TREE_PUBLIC (function);
DECL_VISIBILITY (thunk_fndecl) = DECL_VISIBILITY (function);
DECL_VISIBILITY_SPECIFIED (thunk_fndecl)
= DECL_VISIBILITY_SPECIFIED (function);
if (DECL_ONE_ONLY (function) || DECL_WEAK (function))
make_decl_one_only (thunk_fndecl, cxx_comdat_group (thunk_fndecl));
if (flag_syntax_only)
{
TREE_ASM_WRITTEN (thunk_fndecl) = 1;
return;
}
push_to_top_level ();
if (TARGET_USE_LOCAL_THUNK_ALIAS_P (function)
&& targetm.have_named_sections)
{
resolve_unique_section (function, 0, flag_function_sections);
if (DECL_SECTION_NAME (function) != NULL && DECL_ONE_ONLY (function))
{
resolve_unique_section (thunk_fndecl, 0, flag_function_sections);
/* Output the thunk into the same section as function. */
DECL_SECTION_NAME (thunk_fndecl) = DECL_SECTION_NAME (function);
}
}
/* Set up cloned argument trees for the thunk. */
t = NULL_TREE;
for (a = DECL_ARGUMENTS (function); a; a = TREE_CHAIN (a))
{
tree x = copy_node (a);
TREE_CHAIN (x) = t;
DECL_CONTEXT (x) = thunk_fndecl;
SET_DECL_RTL (x, NULL_RTX);
DECL_HAS_VALUE_EXPR_P (x) = 0;
t = x;
}
a = nreverse (t);
DECL_ARGUMENTS (thunk_fndecl) = a;
TREE_ASM_WRITTEN (thunk_fndecl) = 1;
cgraph_add_thunk (thunk_fndecl, function,
this_adjusting, fixed_offset, virtual_value,
virtual_offset, alias);
if (!this_adjusting
|| !targetm.asm_out.can_output_mi_thunk (thunk_fndecl, fixed_offset,
virtual_value, alias))
{
/* If this is a covariant thunk, or we don't have the necessary
code for efficient thunks, generate a thunk function that
just makes a call to the real function. Unfortunately, this
doesn't work for varargs. */
if (varargs_function_p (function))
error ("generic thunk code fails for method %q#D which uses %<...%>",
function);
}
pop_from_top_level ();
}
