#include "tree.h"
#include "rtl.h"
#include "cp-tree.h"
+#include "tm_p.h"
#include "flags.h"
#include "output.h"
#include "expr.h"
static int comp_cv_target_types PROTO((tree, tree, int));
static void casts_away_constness_r PROTO((tree *, tree *));
static int casts_away_constness PROTO ((tree, tree));
+static void maybe_warn_about_returning_address_of_local PROTO ((tree));
/* Return the target type of TYPE, which means return T for:
T*, T&, T[], T (...), and otherwise, just T. */
return size_int (1);
}
/* It's illegal to say `sizeof (X::i)' for `i' a non-static data
- member unless you're in a non-static member of X. But, we used
- to support this usage, so we still permit it unless we're being
- pedantic. [expr.prim] */
+ member unless you're in a non-static member of X. So hand off to
+ resolve_offset_ref. [expr.prim] */
else if (TREE_CODE (e) == OFFSET_REF)
e = resolve_offset_ref (e);
return cp_convert (ptrtype, adr);
}
+ /* [basic.lval]: Class rvalues can have cv-qualified types; non-class
+ rvalues always have cv-unqualified types. */
+ if (! CLASS_TYPE_P (type))
+ exp = cp_convert (TYPE_MAIN_VARIANT (type), exp);
+
return exp;
}
}
/* Look up component name in the structure type definition. */
- if (CLASSTYPE_VFIELD (basetype)
- && DECL_NAME (CLASSTYPE_VFIELD (basetype)) == component)
+ if (TYPE_VFIELD (basetype)
+ && DECL_NAME (TYPE_VFIELD (basetype)) == component)
/* Special-case this because if we use normal lookups in an ambiguous
hierarchy, the compiler will abort (because vptr lookups are
not supposed to be ambiguous. */
- field = CLASSTYPE_VFIELD (basetype);
+ field = TYPE_VFIELD (basetype);
else if (TREE_CODE (component) == FIELD_DECL)
field = component;
else if (TREE_CODE (component) == TYPE_DECL)
tree instance_ptr = *instance_ptrptr;
+ if (instance_ptr == error_mark_node
+ && TREE_CODE (function) == PTRMEM_CST)
+ {
+ /* Extracting the function address from a pmf is only
+ allowed with -Wno-pmf-conversions. It only works for
+ pmf constants. */
+ e1 = build_addr_func (PTRMEM_CST_MEMBER (function));
+ e1 = convert (TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (function)), e1);
+ return e1;
+ }
+
if (TREE_SIDE_EFFECTS (instance_ptr))
instance_ptr = save_expr (instance_ptr);
NULL_TREE, 0));
e3 = PFN_FROM_PTRMEMFUNC (function);
- if (TYPE_SIZE (basetype) != NULL_TREE
- && ! TYPE_VIRTUAL_P (basetype))
- /* If basetype doesn't have virtual functions, don't emit code to
- handle that case. */
- e1 = e3;
- else
+ /* This used to avoid checking for virtual functions if basetype
+ has no virtual functions, according to an earlier ANSI draft.
+ With the final ISO C++ rules, such an optimization is
+ incorrect: A pointer to a derived member can be static_cast
+ to pointer-to-base-member, as long as the dynamic object
+ later has the right member. */
+
+ /* Promoting idx before saving it improves performance on RISC
+ targets. Without promoting, the first compare used
+ load-with-sign-extend, while the second used normal load then
+ shift to sign-extend. An optimizer flaw, perhaps, but it's
+ easier to make this change. */
+ idx = save_expr (default_conversion
+ (build_component_ref (function,
+ index_identifier,
+ NULL_TREE, 0)));
+ e1 = build_binary_op (GE_EXPR, idx, integer_zero_node);
+
+ /* Convert down to the right base, before using the instance. */
+ instance = convert_pointer_to_real (basetype, instance_ptr);
+ if (instance == error_mark_node && instance_ptr != error_mark_node)
+ return instance;
+
+ vtbl = convert_pointer_to (ptr_type_node, instance);
+ delta2 = DELTA2_FROM_PTRMEMFUNC (function);
+ vtbl = build
+ (PLUS_EXPR,
+ build_pointer_type (build_pointer_type (vtable_entry_type)),
+ vtbl, cp_convert (ptrdiff_type_node, delta2));
+ vtbl = build_indirect_ref (vtbl, NULL_PTR);
+ aref = build_array_ref (vtbl, build_binary_op (MINUS_EXPR,
+ idx,
+ integer_one_node));
+ if (! flag_vtable_thunks)
{
- /* Promoting idx before saving it improves performance on RISC
- targets. Without promoting, the first compare used
- load-with-sign-extend, while the second used normal load then
- shift to sign-extend. An optimizer flaw, perhaps, but it's
- easier to make this change. */
- idx = save_expr (default_conversion
- (build_component_ref (function,
- index_identifier,
- NULL_TREE, 0)));
- e1 = build_binary_op (GE_EXPR, idx, integer_zero_node);
-
- /* Convert down to the right base, before using the instance. */
- instance = convert_pointer_to_real (basetype, instance_ptr);
- if (instance == error_mark_node && instance_ptr != error_mark_node)
- return instance;
-
- vtbl = convert_pointer_to (ptr_type_node, instance);
- delta2 = DELTA2_FROM_PTRMEMFUNC (function);
- vtbl = build
+ aref = save_expr (aref);
+
+ delta = build_binary_op
(PLUS_EXPR,
- build_pointer_type (build_pointer_type (vtable_entry_type)),
- vtbl, cp_convert (ptrdiff_type_node, delta2));
- vtbl = build_indirect_ref (vtbl, NULL_PTR);
- aref = build_array_ref (vtbl, build_binary_op (MINUS_EXPR,
- idx,
- integer_one_node));
- if (! flag_vtable_thunks)
- {
- aref = save_expr (aref);
-
- delta = build_binary_op
- (PLUS_EXPR,
- build_conditional_expr (e1,
- build_component_ref (aref,
- delta_identifier,
- NULL_TREE, 0),
- integer_zero_node),
- delta);
- }
-
- if (flag_vtable_thunks)
- e2 = aref;
- else
- e2 = build_component_ref (aref, pfn_identifier, NULL_TREE, 0);
- TREE_TYPE (e2) = TREE_TYPE (e3);
- e1 = build_conditional_expr (e1, e2, e3);
-
- /* Make sure this doesn't get evaluated first inside one of the
- branches of the COND_EXPR. */
- if (TREE_CODE (instance_ptr) == SAVE_EXPR)
- e1 = build (COMPOUND_EXPR, TREE_TYPE (e1),
- instance_ptr, e1);
+ build_conditional_expr (e1,
+ build_component_ref (aref,
+ delta_identifier,
+ NULL_TREE, 0),
+ integer_zero_node),
+ delta);
}
+ if (flag_vtable_thunks)
+ e2 = aref;
+ else
+ e2 = build_component_ref (aref, pfn_identifier, NULL_TREE, 0);
+ TREE_TYPE (e2) = TREE_TYPE (e3);
+ e1 = build_conditional_expr (e1, e2, e3);
+
+ /* Make sure this doesn't get evaluated first inside one of the
+ branches of the COND_EXPR. */
+ if (TREE_CODE (instance_ptr) == SAVE_EXPR)
+ e1 = build (COMPOUND_EXPR, TREE_TYPE (e1),
+ instance_ptr, e1);
+
*instance_ptrptr = build (PLUS_EXPR, TREE_TYPE (instance_ptr),
instance_ptr, delta);
if (TREE_CODE (function) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL
- && DECL_BUILT_IN (TREE_OPERAND (function, 0)))
+ && DECL_BUILT_IN (TREE_OPERAND (function, 0))
+ && DECL_BUILT_IN_CLASS (TREE_OPERAND (function, 0)) == BUILT_IN_NORMAL)
switch (DECL_FUNCTION_CODE (TREE_OPERAND (function, 0)))
{
case BUILT_IN_ABS:
case EQ_EXPR:
case NE_EXPR:
+ if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
+ warning ("comparing floating point with == or != is unsafe");
+
build_type = boolean_type_node;
if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
|| code0 == COMPLEX_TYPE)
DECL_VINDEX (TREE_OPERAND (op1, 0)),
integer_one_node);
op1 = integer_zero_node;
- delta21 = CLASSTYPE_VFIELD (TYPE_METHOD_BASETYPE
- (TREE_TYPE (type1)));
+ delta21 = TYPE_VFIELD (TYPE_METHOD_BASETYPE
+ (TREE_TYPE (type1)));
delta21 = DECL_FIELD_BITPOS (delta21);
delta21 = size_binop (FLOOR_DIV_EXPR, delta21,
size_int (BITS_PER_UNIT));
|| code == POSTINCREMENT_EXPR)
? PLUS_EXPR : MINUS_EXPR),
argtype, value, inc);
- TREE_SIDE_EFFECTS (incremented) = 1;
modify = build_modify_expr (arg, NOP_EXPR, incremented);
compound = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
arg = stabilize_reference (arg);
val = build (MODIFY_EXPR, TREE_TYPE (arg), arg,
boolean_true_node);
- TREE_SIDE_EFFECTS (val) = 1;
arg = save_expr (arg);
val = build (COMPOUND_EXPR, TREE_TYPE (arg), val, arg);
val = build (COMPOUND_EXPR, TREE_TYPE (arg), arg, val);
return fold (build1 (code, argtype, arg));
}
- error (errstring);
+ error ("%s", errstring);
return error_mark_node;
}
&& DECL_RTL (x) != 0
&& ! DECL_IN_MEMORY_P (x))
{
- /* We thought this would make a good constant variable,
- but we were wrong. */
- push_permanent_obstack ();
-
TREE_ASM_WRITTEN (x) = 0;
DECL_RTL (x) = 0;
rest_of_decl_compilation (x, 0,
0);
TREE_ADDRESSABLE (x) = 1;
- pop_obstacks ();
-
return 1;
}
/* Caller should not be trying to mark initialized
&& !DECL_ARTIFICIAL (x) && extra_warnings)
cp_warning ("address requested for `%D', which is declared `register'",
x);
- put_var_into_stack (x);
TREE_ADDRESSABLE (x) = 1;
+ TREE_USED (x) = 1;
+ if (current_function && expanding_p)
+ put_var_into_stack (x);
return 1;
case FUNCTION_DECL:
}
}
- /* check to see if there is an assignment to `this' */
- if (lhs == current_class_ptr)
- {
- if (flag_this_is_variable > 0
- && DECL_NAME (current_function_decl) != NULL_TREE
- && (DECL_NAME (current_function_decl)
- != constructor_name (current_class_type)))
- warning ("assignment to `this' not in constructor or destructor");
- current_function_just_assigned_this = 1;
- }
-
if (modifycode != INIT_EXPR)
{
/* Make modifycode now either a NOP_EXPR or an INIT_EXPR. */
{
newrhs = convert_for_initialization (lhs, lhstype, newrhs, LOOKUP_NORMAL,
"assignment", NULL_TREE, 0);
- if (lhs == DECL_RESULT (current_function_decl))
+ if (current_function_decl &&
+ lhs == DECL_RESULT (current_function_decl))
{
if (DECL_INITIAL (lhs))
warning ("return value from function receives multiple initializations");
if (TREE_CODE (rhs) == TREE_LIST && TREE_VALUE (rhs) == error_mark_node)
return error_mark_node;
- /* Issue warnings about peculiar, but legal, uses of NULL. */
+ /* Issue warnings about peculiar, but legal, uses of NULL. We
+ do this *before* the call to decl_constant_value so as to
+ avoid duplicate warnings on code like `const int I = NULL;
+ f(I);'. */
if (ARITHMETIC_TYPE_P (type) && rhs == null_node)
cp_warning ("converting NULL to non-pointer type");
cv-unqualified type of the left operand. */
if (!can_convert_arg (type, rhstype, rhs))
{
- /* When -Wno-pmf-converions is use, we just silently allow
+ /* When -Wno-pmf-conversions is use, we just silently allow
conversions from pointers-to-members to plain pointers. If
the conversion doesn't work, cp_convert will complain. */
if (!warn_pmf2ptr
&& TYPE_PTR_P (type)
&& TYPE_PTRMEMFUNC_P (rhstype))
rhs = cp_convert (strip_top_quals (type), rhs);
- /* If the right-hand side has unknown type, then it is an
- overloaded function. Call instantiate_type to get error
- messages. */
- else if (rhstype == unknown_type_node)
- instantiate_type (type, rhs, 1);
- else if (fndecl)
- cp_error ("cannot convert `%T' to `%T' for argument `%P' to `%D'",
- rhstype, type, parmnum, fndecl);
- else
- cp_error ("cannot convert `%T' to `%T' in %s", rhstype, type,
- errtype);
- return error_mark_node;
+ else
+ {
+ /* If the right-hand side has unknown type, then it is an
+ overloaded function. Call instantiate_type to get error
+ messages. */
+ if (rhstype == unknown_type_node)
+ instantiate_type (type, rhs, 1);
+ else if (fndecl)
+ cp_error ("cannot convert `%T' to `%T' for argument `%P' to `%D'",
+ rhstype, type, parmnum, fndecl);
+ else
+ cp_error ("cannot convert `%T' to `%T' in %s", rhstype, type,
+ errtype);
+ return error_mark_node;
+ }
}
return perform_implicit_conversion (strip_top_quals (type), rhs);
}
if (IS_AGGR_TYPE (type))
return ocp_convert (type, rhs, CONV_IMPLICIT|CONV_FORCE_TEMP, flags);
- if (type == TREE_TYPE (rhs))
- {
- /* Issue warnings about peculiar, but legal, uses of NULL. We
- do this *before* the call to decl_constant_value so as to
- avoid duplicate warnings on code like `const int I = NULL;
- f(I);'. */
- if (ARITHMETIC_TYPE_P (type) && rhs == null_node)
- cp_warning ("converting NULL to non-pointer type");
-
- if (TREE_READONLY_DECL_P (rhs))
- rhs = decl_constant_value (rhs);
-
- return rhs;
- }
-
return convert_for_assignment (type, rhs, errtype, fndecl, parmnum);
}
\f
emit_queue ();
}
\f
-/* Expand a C `return' statement.
- RETVAL is the expression for what to return,
- or a null pointer for `return;' with no value.
+/* If RETVAL is the address of, or a reference to, a local variable or
+ temporary give an appropraite warning. */
- C++: upon seeing a `return', we must call destructors on all
- variables in scope which had constructors called on them.
- This means that if in a destructor, the base class destructors
- must be called before returning.
+static void
+maybe_warn_about_returning_address_of_local (retval)
+ tree retval;
+{
+ tree valtype = TREE_TYPE (DECL_RESULT (current_function_decl));
- The RETURN statement in C++ has initialization semantics. */
+ if (TREE_CODE (valtype) == REFERENCE_TYPE)
+ {
+ tree whats_returned;
-void
-c_expand_return (retval)
+ /* Sort through common things to see what it is
+ we are returning. */
+ whats_returned = retval;
+ if (TREE_CODE (whats_returned) == COMPOUND_EXPR)
+ {
+ whats_returned = TREE_OPERAND (whats_returned, 1);
+ if (TREE_CODE (whats_returned) == ADDR_EXPR)
+ whats_returned = TREE_OPERAND (whats_returned, 0);
+ }
+ while (TREE_CODE (whats_returned) == CONVERT_EXPR
+ || TREE_CODE (whats_returned) == NOP_EXPR)
+ whats_returned = TREE_OPERAND (whats_returned, 0);
+ if (TREE_CODE (whats_returned) == ADDR_EXPR)
+ {
+ whats_returned = TREE_OPERAND (whats_returned, 0);
+ while (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
+ || TREE_CODE (whats_returned) == TARGET_EXPR)
+ {
+ /* Get the target. */
+ whats_returned = TREE_OPERAND (whats_returned, 0);
+ warning ("returning reference to temporary");
+ }
+ }
+
+ if (TREE_CODE (whats_returned) == VAR_DECL
+ && DECL_NAME (whats_returned))
+ {
+ if (TEMP_NAME_P (DECL_NAME (whats_returned)))
+ warning ("reference to non-lvalue returned");
+ else if (TREE_CODE (TREE_TYPE (whats_returned)) != REFERENCE_TYPE
+ && DECL_FUNCTION_SCOPE_P (whats_returned)
+ && !(TREE_STATIC (whats_returned)
+ || TREE_PUBLIC (whats_returned)))
+ cp_warning_at ("reference to local variable `%D' returned",
+ whats_returned);
+ }
+ }
+ else if (TREE_CODE (retval) == ADDR_EXPR)
+ {
+ tree whats_returned = TREE_OPERAND (retval, 0);
+
+ if (TREE_CODE (whats_returned) == VAR_DECL
+ && DECL_NAME (whats_returned)
+ && DECL_FUNCTION_SCOPE_P (whats_returned)
+ && !(TREE_STATIC (whats_returned)
+ || TREE_PUBLIC (whats_returned)))
+ cp_warning_at ("address of local variable `%D' returned",
+ whats_returned);
+ }
+}
+
+/* Check that returning RETVAL from the current function is legal.
+ Return an expression explicitly showing all conversions required to
+ change RETVAL into the function return type, and to assign it to
+ the DECL_RESULT for the function. */
+
+tree
+check_return_expr (retval)
tree retval;
{
- tree result = DECL_RESULT (current_function_decl);
- tree valtype = TREE_TYPE (result);
-
+ tree result;
+ /* The type actually returned by the function, after any
+ promotions. */
+ tree valtype;
+ int fn_returns_value_p;
+
+ /* A `volatile' function is one that isn't supposed to return, ever.
+ (This is a G++ extension, used to get better code for functions
+ that call the `volatile' function.) */
if (TREE_THIS_VOLATILE (current_function_decl))
warning ("function declared `noreturn' has a `return' statement");
+ /* Check for various simple errors. */
if (retval == error_mark_node)
{
+ /* If an error occurred, there's nothing to do. */
current_function_returns_null = 1;
- return;
+ return error_mark_node;
}
-
- if (dtor_label)
+ else if (dtor_label)
{
if (retval)
error ("returning a value from a destructor");
-
- /* Can't just return from a destructor. */
- expand_goto (dtor_label);
- return;
+ return NULL_TREE;
}
else if (in_function_try_handler
&& DECL_CONSTRUCTOR_P (current_function_decl))
/* If a return statement appears in a handler of the
function-try-block of a constructor, the program is ill-formed. */
error ("cannot return from a handler of a function-try-block of a constructor");
- return;
+ return error_mark_node;
+ }
+ else if (retval && DECL_CONSTRUCTOR_P (current_function_decl))
+ /* You can't return a value from a constructor. */
+ error ("returning a value from a constructor");
+
+ /* Constructors actually always return `this', even though in C++
+ you can't return a value from a constructor. */
+ if (DECL_CONSTRUCTOR_P (current_function_decl))
+ retval = current_class_ptr;
+
+ /* When no explicit return-value is given in a function with a named
+ return value, the named return value is used. */
+ result = DECL_RESULT (current_function_decl);
+ valtype = TREE_TYPE (result);
+ my_friendly_assert (valtype != NULL_TREE, 19990924);
+ fn_returns_value_p = !same_type_p (valtype, void_type_node);
+ if (!retval && DECL_NAME (result) && fn_returns_value_p)
+ retval = result;
+
+ /* Check for a return statement with no return value in a function
+ that's supposed to return a value. */
+ if (!retval && fn_returns_value_p)
+ {
+ pedwarn ("`return' with no value, in function returning non-void");
+ /* Clear this, so finish_function won't say that we reach the
+ end of a non-void function (which we don't, we gave a
+ return!). */
+ current_function_returns_null = 0;
+ }
+ /* Check for a return statement with a value in a function that
+ isn't supposed to return a value. */
+ else if (retval && !fn_returns_value_p)
+ {
+ if (same_type_p (TREE_TYPE (retval), void_type_node))
+ /* You can return a `void' value from a function of `void'
+ type. In that case, we have to evaluate the expression for
+ its side-effects. */
+ finish_expr_stmt (retval);
+ else
+ pedwarn ("`return' with a value, in function returning void");
+
+ current_function_returns_null = 1;
+
+ /* There's really no value to return, after all. */
+ return NULL_TREE;
}
+ else if (!retval)
+ /* Remember that this function can sometimes return without a
+ value. */
+ current_function_returns_null = 1;
/* Only operator new(...) throw(), can return NULL [expr.new/13]. */
if ((DECL_NAME (current_function_decl) == ansi_opname[(int) NEW_EXPR]
&& !TYPE_NOTHROW_P (TREE_TYPE (current_function_decl))
&& null_ptr_cst_p (retval))
cp_warning ("operator new should throw an exception, not return NULL");
-
- if (retval == NULL_TREE)
- {
- /* A non-named return value does not count. */
-
- if (DECL_CONSTRUCTOR_P (current_function_decl))
- retval = current_class_ptr;
- else if (DECL_NAME (result) != NULL_TREE
- && TREE_CODE (valtype) != VOID_TYPE)
- retval = result;
- else
- {
- current_function_returns_null = 1;
-
- if (valtype != NULL_TREE && TREE_CODE (valtype) != VOID_TYPE)
- {
- if (DECL_NAME (DECL_RESULT (current_function_decl)) == NULL_TREE)
- {
- pedwarn ("`return' with no value, in function returning non-void");
- /* Clear this, so finish_function won't say that we
- reach the end of a non-void function (which we don't,
- we gave a return!). */
- current_function_returns_null = 0;
- }
- }
-
- expand_null_return ();
- return;
- }
- }
- else if (DECL_CONSTRUCTOR_P (current_function_decl))
- {
- if (flag_this_is_variable)
- error ("return from a constructor: use `this = ...' instead");
- else
- error ("returning a value from a constructor");
- retval = current_class_ptr;
- }
/* Effective C++ rule 15. See also start_function. */
if (warn_ecpp
&& retval != current_class_ref)
cp_warning ("`operator=' should return a reference to `*this'");
- if (valtype == NULL_TREE || TREE_CODE (valtype) == VOID_TYPE)
- {
- current_function_returns_null = 1;
- if (TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
- pedwarn ("`return' with a value, in function returning void");
- expand_return (retval);
- return;
- }
-
- /* Now deal with possible C++ hair:
- (1) Compute the return value.
- (2) If there are aggregate values with destructors which
- must be cleaned up, clean them (taking care
- not to clobber the return value).
- (3) If an X(X&) constructor is defined, the return
- value must be returned via that. */
-
- if (retval == result
- || DECL_CONSTRUCTOR_P (current_function_decl))
- /* It's already done for us. */;
- else if (TREE_CODE (TREE_TYPE (retval)) == VOID_TYPE)
- {
- pedwarn ("return of void value in function returning non-void");
- expand_expr_stmt (retval);
- retval = 0;
- }
+ /* We don't need to do any conversions when there's nothing being
+ returned. */
+ if (!retval)
+ return NULL_TREE;
+
+ /* Do any required conversions. */
+ if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
+ /* No conversions are required. */
+ ;
else
{
+ /* The type the function is declared to return. */
tree functype = TREE_TYPE (TREE_TYPE (current_function_decl));
/* First convert the value to the function's return type, then
to the type of return value's location to handle the
case that functype is thiner than the valtype. */
-
retval = convert_for_initialization
(NULL_TREE, functype, retval, LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING,
"return", NULL_TREE, 0);
-
retval = convert (valtype, retval);
+ /* If the conversion failed, treat this just like `return;'. */
if (retval == error_mark_node)
- {
- /* Avoid warning about control reaching end of function. */
- expand_null_return ();
- return;
- }
-
+ return NULL_TREE;
/* We can't initialize a register from a AGGR_INIT_EXPR. */
else if (! current_function_returns_struct
&& TREE_CODE (retval) == TARGET_EXPR
&& TREE_CODE (TREE_OPERAND (retval, 1)) == AGGR_INIT_EXPR)
retval = build (COMPOUND_EXPR, TREE_TYPE (retval), retval,
TREE_OPERAND (retval, 0));
+ else
+ maybe_warn_about_returning_address_of_local (retval);
+ }
+
+ /* Actually copy the value returned into the appropriate location. */
+ if (retval && retval != result)
+ retval = build (INIT_EXPR, TREE_TYPE (result), result, retval);
- /* Add some useful error checking for C++. */
- else if (TREE_CODE (valtype) == REFERENCE_TYPE)
- {
- tree whats_returned;
-
- /* Sort through common things to see what it is
- we are returning. */
- whats_returned = retval;
- if (TREE_CODE (whats_returned) == COMPOUND_EXPR)
- {
- whats_returned = TREE_OPERAND (whats_returned, 1);
- if (TREE_CODE (whats_returned) == ADDR_EXPR)
- whats_returned = TREE_OPERAND (whats_returned, 0);
- }
- while (TREE_CODE (whats_returned) == CONVERT_EXPR
- || TREE_CODE (whats_returned) == NOP_EXPR)
- whats_returned = TREE_OPERAND (whats_returned, 0);
- if (TREE_CODE (whats_returned) == ADDR_EXPR)
- {
- whats_returned = TREE_OPERAND (whats_returned, 0);
- while (TREE_CODE (whats_returned) == AGGR_INIT_EXPR
- || TREE_CODE (whats_returned) == TARGET_EXPR)
- {
- /* Get the target. */
- whats_returned = TREE_OPERAND (whats_returned, 0);
- warning ("returning reference to temporary");
- }
- }
+ /* All done. Remember that this function did return a value. */
+ current_function_returns_value = 1;
+ return retval;
+}
- if (TREE_CODE (whats_returned) == VAR_DECL && DECL_NAME (whats_returned))
- {
- if (TEMP_NAME_P (DECL_NAME (whats_returned)))
- warning ("reference to non-lvalue returned");
- else if (TREE_CODE (TREE_TYPE (whats_returned)) != REFERENCE_TYPE
- && DECL_FUNCTION_SCOPE_P (whats_returned)
- && !(TREE_STATIC (whats_returned)
- || TREE_PUBLIC (whats_returned)))
- cp_warning_at ("reference to local variable `%D' returned", whats_returned);
- }
- }
- else if (TREE_CODE (retval) == ADDR_EXPR)
- {
- tree whats_returned = TREE_OPERAND (retval, 0);
-
- if (TREE_CODE (whats_returned) == VAR_DECL
- && DECL_NAME (whats_returned)
- && DECL_FUNCTION_SCOPE_P (whats_returned)
- && !(TREE_STATIC (whats_returned)
- || TREE_PUBLIC (whats_returned)))
- cp_warning_at ("address of local variable `%D' returned", whats_returned);
- }
- }
+/* Expand a C `return' statement.
+ RETVAL is the expression for what to return,
+ or a null pointer for `return;' with no value.
- if (retval != NULL_TREE
- && TREE_CODE_CLASS (TREE_CODE (retval)) == 'd'
- && ! in_control_zone_p ())
- current_function_return_value = retval;
+ C++: upon seeing a `return', we must call destructors on all
+ variables in scope which had constructors called on them.
+ This means that if in a destructor, the base class destructors
+ must be called before returning.
- if (ctor_label && TREE_CODE (ctor_label) != ERROR_MARK)
- {
- /* Here RETVAL is CURRENT_CLASS_PTR, so there's nothing to do. */
- expand_goto (ctor_label);
- }
+ The RETURN statement in C++ has initialization semantics. */
- if (retval && retval != result)
+void
+c_expand_return (retval)
+ tree retval;
+{
+ if (!retval)
+ expand_null_return ();
+ else
{
- result = build (INIT_EXPR, TREE_TYPE (result), result, retval);
- TREE_SIDE_EFFECTS (result) = 1;
+ expand_start_target_temps ();
+ expand_return (retval);
+ expand_end_target_temps ();
}
-
- expand_start_target_temps ();
-
- expand_return (result);
-
- expand_end_target_temps ();
-
- current_function_returns_value = 1;
}
\f
/* Start a C switch statement, testing expression EXP.
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