+ /* If nonnull, this function checks whether a PCH file with the
+ given set of target flags can be used. It returns NULL if so,
+ otherwise it returns an error message. */
+ const char *(*check_pch_target_flags) (int);
+
+ /* True if the compiler should give an enum type only as many
+ bytes as it takes to represent the range of possible values of
+ that type. */
+ bool (* default_short_enums) (void);
+
+ /* This target hook returns an rtx that is used to store the address
+ of the current frame into the built-in setjmp buffer. */
+ rtx (* builtin_setjmp_frame_value) (void);
+
+ /* This target hook should add STRING_CST trees for any hard regs
+ the port wishes to automatically clobber for an asm. */
+ tree (* md_asm_clobbers) (tree, tree, tree);
+
+ /* This target hook allows the backend to specify a calling convention
+ in the debug information. This function actually returns an
+ enum dwarf_calling_convention, but because of forward declarations
+ and not wanting to include dwarf2.h everywhere target.h is included
+ the function is being declared as an int. */
+ int (* dwarf_calling_convention) (tree);
+
+ /* This target hook allows the backend to emit frame-related insns that
+ contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
+ engine will invoke it on insns of the form
+ (set (reg) (unspec [...] UNSPEC_INDEX))
+ and
+ (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
+ to let the backend emit the call frame instructions. */
+ void (* dwarf_handle_frame_unspec) (const char *, rtx, int);
+
+ /* Perform architecture specific checking of statements gimplified
+ from VA_ARG_EXPR. LHS is left hand side of MODIFY_EXPR, RHS
+ is right hand side. Returns true if the statements doesn't need
+ to be checked for va_list references. */
+ bool (* stdarg_optimize_hook) (struct stdarg_info *ai, tree lhs, tree rhs);
+
+ /* This target hook allows the operating system to override the DECL
+ that represents the external variable that contains the stack
+ protection guard variable. The type of this DECL is ptr_type_node. */
+ tree (* stack_protect_guard) (void);
+
+ /* This target hook allows the operating system to override the CALL_EXPR
+ that is invoked when a check vs the guard variable fails. */
+ tree (* stack_protect_fail) (void);
+
+ /* Returns NULL if target supports the insn within a doloop block,
+ otherwise it returns an error message. */
+ const char * (*invalid_within_doloop) (rtx);
+
+ /* DECL is a variable or function with __attribute__((dllimport))
+ specified. Use this hook if the target needs to add extra validation
+ checks to handle_dll_attribute (). */
+ bool (* valid_dllimport_attribute_p) (tree decl);
+
+ /* Functions relating to calls - argument passing, returns, etc. */
+ struct calls {
+ bool (*promote_function_args) (tree fntype);
+ bool (*promote_function_return) (tree fntype);
+ bool (*promote_prototypes) (tree fntype);
+ rtx (*struct_value_rtx) (tree fndecl, int incoming);
+ bool (*return_in_memory) (tree type, tree fndecl);
+ bool (*return_in_msb) (tree type);
+
+ /* Return true if a parameter must be passed by reference. TYPE may
+ be null if this is a libcall. CA may be null if this query is
+ from __builtin_va_arg. */
+ bool (*pass_by_reference) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
+ tree type, bool named_arg);
+
+ rtx (*expand_builtin_saveregs) (void);
+ /* Returns pretend_argument_size. */
+ void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
+ tree type, int *pretend_arg_size,
+ int second_time);
+ bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
+ /* Returns true if we should use
+ targetm.calls.setup_incoming_varargs() and/or
+ targetm.calls.strict_argument_naming(). */
+ bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
+
+ /* Given a complex type T, return true if a parameter of type T
+ should be passed as two scalars. */
+ bool (* split_complex_arg) (tree type);
+
+ /* Return true if type T, mode MODE, may not be passed in registers,
+ but must be passed on the stack. */
+ /* ??? This predicate should be applied strictly after pass-by-reference.
+ Need audit to verify that this is the case. */
+ bool (* must_pass_in_stack) (enum machine_mode mode, tree t);
+
+ /* Return true if type TYPE, mode MODE, which is passed by reference,
+ should have the object copy generated by the callee rather than
+ the caller. It is never called for TYPE requiring constructors. */
+ bool (* callee_copies) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
+ tree type, bool named);
+
+ /* Return zero for arguments passed entirely on the stack or entirely
+ in registers. If passed in both, return the number of bytes passed
+ in registers; the balance is therefore passed on the stack. */
+ int (* arg_partial_bytes) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
+ tree type, bool named);
+
+ /* Return the diagnostic message string if function without a prototype
+ is not allowed for this 'val' argument; NULL otherwise. */
+ const char *(*invalid_arg_for_unprototyped_fn) (tree typelist,
+ tree funcdecl, tree val);
+
+ /* Return an rtx for the return value location of the function
+ specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
+ rtx (*function_value) (tree ret_type, tree fn_decl_or_type,
+ bool outgoing);
+
+ /* Return an rtx for the argument pointer incoming to the
+ current function. */
+ rtx (*internal_arg_pointer) (void);
+ } calls;
+
+ /* Return the diagnostic message string if conversion from FROMTYPE
+ to TOTYPE is not allowed, NULL otherwise. */
+ const char *(*invalid_conversion) (tree fromtype, tree totype);
+
+ /* Return the diagnostic message string if the unary operation OP is
+ not permitted on TYPE, NULL otherwise. */
+ const char *(*invalid_unary_op) (int op, tree type);
+
+ /* Return the diagnostic message string if the binary operation OP
+ is not permitted on TYPE1 and TYPE2, NULL otherwise. */
+ const char *(*invalid_binary_op) (int op, tree type1, tree type2);
+
+ /* Return the class for a secondary reload, and fill in extra information. */
+ enum reg_class (*secondary_reload) (bool, rtx, enum reg_class,
+ enum machine_mode,
+ struct secondary_reload_info *);
+
+ /* Functions specific to the C++ frontend. */
+ struct cxx {
+ /* Return the integer type used for guard variables. */
+ tree (*guard_type) (void);
+ /* Return true if only the low bit of the guard should be tested. */
+ bool (*guard_mask_bit) (void);
+ /* Returns the size of the array cookie for an array of type. */
+ tree (*get_cookie_size) (tree);
+ /* Returns true if the element size should be stored in the
+ array cookie. */
+ bool (*cookie_has_size) (void);
+ /* Allows backends to perform additional processing when
+ deciding if a class should be exported or imported. */
+ int (*import_export_class) (tree, int);
+ /* Returns true if constructors and destructors return "this". */
+ bool (*cdtor_returns_this) (void);
+ /* Returns true if the key method for a class can be an inline
+ function, so long as it is not declared inline in the class
+ itself. Returning true is the behavior required by the Itanium
+ C++ ABI. */
+ bool (*key_method_may_be_inline) (void);
+ /* DECL is a virtual table, virtual table table, typeinfo object,
+ or other similar implicit class data object that will be
+ emitted with external linkage in this translation unit. No ELF
+ visibility has been explicitly specified. If the target needs
+ to specify a visibility other than that of the containing class,
+ use this hook to set DECL_VISIBILITY and
+ DECL_VISIBILITY_SPECIFIED. */
+ void (*determine_class_data_visibility) (tree decl);
+ /* Returns true (the default) if virtual tables and other
+ similar implicit class data objects are always COMDAT if they
+ have external linkage. If this hook returns false, then
+ class data for classes whose virtual table will be emitted in
+ only one translation unit will not be COMDAT. */
+ bool (*class_data_always_comdat) (void);
+ /* Returns true if __aeabi_atexit should be used to register static
+ destructors. */
+ bool (*use_aeabi_atexit) (void);
+ /* 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 visibility or perform any other required
+ target modifications). */
+ void (*adjust_class_at_definition) (tree type);
+ } cxx;
+
+ /* For targets that need to mark extra registers as live on entry to
+ the function, they should define this target hook and set their
+ bits in the bitmap passed in. */
+ void (*live_on_entry) (bitmap);
+
+ /* True if unwinding tables should be generated by default. */
+ bool unwind_tables_default;
+