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/* Data structure definitions for a generic GCC target.

   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

   Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify it

   under the terms of the GNU General Public License as published by the

   Free Software Foundation; either version 3, or (at your option) any

   later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program; see the file COPYING3.  If not see

   <http://www.gnu.org/licenses/>.

   In other words, you are welcome to use, share and improve this program.

   You are forbidden to forbid anyone else to use, share and improve

   what you give them.   Help stamp out software-hoarding!  */

/* This file contains a data structure that describes a GCC target.

   At present it is incomplete, but in future it should grow to

   contain most or all target machine and target O/S specific

   information.

   This structure has its initializer declared in target-def.h in the

   form of large macro TARGET_INITIALIZER that expands to many smaller

   macros.

   The smaller macros each initialize one component of the structure,

   and each has a default.  Each target should have a file that

   includes target.h and target-def.h, and overrides any inappropriate

   defaults by undefining the relevant macro and defining a suitable

   replacement.  That file should then contain the definition of

   "targetm" like so:

   struct gcc_target targetm = TARGET_INITIALIZER;

   Doing things this way allows us to bring together everything that

   defines a GCC target.  By supplying a default that is appropriate

   to most targets, we can easily add new items without needing to

   edit dozens of target configuration files.  It should also allow us

   to gradually reduce the amount of conditional compilation that is

   scattered throughout GCC.  */

#ifndef GCC_TARGET_H

#define GCC_TARGET_H

#include "tm.h"

#include "insn-modes.h"

/* Types used by the record_gcc_switches() target function.  */

typedef enum

{

  SWITCH_TYPE_PASSED,           /* A switch passed on the command line.  */

  SWITCH_TYPE_ENABLED,          /* An option that is currently enabled.  */

  SWITCH_TYPE_DESCRIPTIVE,      /* Descriptive text, not a switch or option.  */

  SWITCH_TYPE_LINE_START,       /* Please emit any necessary text at the start of a line.  */

  SWITCH_TYPE_LINE_END          /* Please emit a line terminator.  */

}

print_switch_type;

typedef int (* print_switch_fn_type) (print_switch_type, const char *);

/* An example implementation for ELF targets.  Defined in varasm.c  */

extern int elf_record_gcc_switches (print_switch_type type, const char *);

/* Some places still assume that all pointer or address modes are the

   standard Pmode and ptr_mode.  These optimizations become invalid if

   the target actually supports multiple different modes.  For now,

   we disable such optimizations on such targets, using this function.  */

extern bool target_default_pointer_address_modes_p (void);

struct stdarg_info;

struct spec_info_def;

/* The struct used by the secondary_reload target hook.  */

typedef struct secondary_reload_info

{

  /* icode is actually an enum insn_code, but we don't want to force every

     file that includes target.h to include optabs.h .  */

  int icode;

  int extra_cost; /* Cost for using (a) scratch register(s) to be taken

                     into account by copy_cost.  */

  /* The next two members are for the use of the backward

     compatibility hook.  */

  struct secondary_reload_info *prev_sri;

  int t_icode; /* Actually an enum insn_code - see above.  */

} secondary_reload_info;

/* This is defined in sched-int.h .  */

struct _dep;

/* This is defined in ddg.h .  */

struct ddg;

/* Assembler instructions for creating various kinds of integer object.  */

struct asm_int_op

{

  const char *hi;

  const char *si;

  const char *di;

  const char *ti;

};

/* The target structure.  This holds all the backend hooks.  */

struct gcc_target

{

  /* Functions that output assembler for the target.  */

  struct asm_out

  {

    /* Opening and closing parentheses for asm expression grouping.  */

    const char *open_paren, *close_paren;

    /* Assembler instructions for creating various kinds of integer object.  */

    const char *byte_op;

    struct asm_int_op aligned_op, unaligned_op;

    /* Try to output the assembler code for an integer object whose

       value is given by X.  SIZE is the size of the object in bytes and

       ALIGNED_P indicates whether it is aligned.  Return true if

       successful.  Only handles cases for which BYTE_OP, ALIGNED_OP

       and UNALIGNED_OP are NULL.  */

    bool (* integer) (rtx x, unsigned int size, int aligned_p);

    /* Output code that will globalize a label.  */

    void (* globalize_label) (FILE *, const char *);

    /* Output code that will globalize a declaration.  */

    void (* globalize_decl_name) (FILE *, tree);

    /* Output code that will emit a label for unwind info, if this

       target requires such labels.  Second argument is the decl the

       unwind info is associated with, third is a boolean: true if

       this is for exception handling, fourth is a boolean: true if

       this is only a placeholder for an omitted FDE.  */

    void (* unwind_label) (FILE *, tree, int, int);

    /* Output code that will emit a label to divide up the exception

       table.  */

    void (* except_table_label) (FILE *);

    /* Emit any directives required to unwind this instruction.  */

    void (* unwind_emit) (FILE *, rtx);

    /* Output an internal label.  */

    void (* internal_label) (FILE *, const char *, unsigned long);

    /* Emit a ttype table reference to a typeinfo object.  */

    bool (* ttype) (rtx);

    /* Emit an assembler directive to set visibility for the symbol

       associated with the tree decl.  */

    void (* visibility) (tree, int);

    /* Output the assembler code for entry to a function.  */

    void (* function_prologue) (FILE *, HOST_WIDE_INT);

    /* Output the assembler code for end of prologue.  */

    void (* function_end_prologue) (FILE *);

    /* Output the assembler code for start of epilogue.  */

    void (* function_begin_epilogue) (FILE *);

    /* Output the assembler code for function exit.  */

    void (* function_epilogue) (FILE *, HOST_WIDE_INT);

    /* Initialize target-specific sections.  */

    void (* init_sections) (void);

    /* Tell assembler to change to section NAME with attributes FLAGS.

       If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with

       which this section is associated.  */

    void (* named_section) (const char *name, unsigned int flags, tree decl);

    /* Return a mask describing how relocations should be treated when

       selecting sections.  Bit 1 should be set if global relocations

       should be placed in a read-write section; bit 0 should be set if

       local relocations should be placed in a read-write section.  */

    int (*reloc_rw_mask) (void);

    /* Return a section for EXP.  It may be a DECL or a constant.  RELOC

       is nonzero if runtime relocations must be applied; bit 1 will be

       set if the runtime relocations require non-local name resolution.

       ALIGN is the required alignment of the data.  */

    section *(* select_section) (tree, int, unsigned HOST_WIDE_INT);

    /* Return a section for X.  MODE is X's mode and ALIGN is its

       alignment in bits.  */

    section *(* select_rtx_section) (enum machine_mode, rtx,

                                     unsigned HOST_WIDE_INT);

    /* Select a unique section name for DECL.  RELOC is the same as

       for SELECT_SECTION.  */

    void (* unique_section) (tree, int);

    /* Return the readonly data section associated with function DECL.  */

    section *(* function_rodata_section) (tree);

    /* Output a constructor for a symbol with a given priority.  */

    void (* constructor) (rtx, int);

    /* Output a destructor for a symbol with a given priority.  */

    void (* destructor) (rtx, int);

    /* Output the assembler code for a thunk function.  THUNK_DECL is the

       declaration for the thunk function itself, FUNCTION is the decl for

       the target function.  DELTA is an immediate constant offset to be

       added to THIS.  If VCALL_OFFSET is nonzero, the word at

       *(*this + vcall_offset) should be added to THIS.  */

    void (* output_mi_thunk) (FILE *file, tree thunk_decl,

                              HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,

                              tree function_decl);

    /* Determine whether output_mi_thunk would succeed.  */

    /* ??? Ideally, this hook would not exist, and success or failure

       would be returned from output_mi_thunk directly.  But there's

       too much undo-able setup involved in invoking output_mi_thunk.

       Could be fixed by making output_mi_thunk emit rtl instead of

       text to the output file.  */

    bool (* can_output_mi_thunk) (const_tree thunk_decl, HOST_WIDE_INT delta,

                                  HOST_WIDE_INT vcall_offset,

                                  const_tree function_decl);

    /* Output any boilerplate text needed at the beginning of a

       translation unit.  */

    void (*file_start) (void);

    /* Output any boilerplate text needed at the end of a

       translation unit.  */

    void (*file_end) (void);

    /* Output any boilerplate text needed at the beginning of an

       LTO output stream.  */

    void (*lto_start) (void);

    /* Output any boilerplate text needed at the end of an

       LTO output stream.  */

    void (*lto_end) (void);

    /* Output any boilerplace text needed at the end of a

       translation unit before debug and unwind info is emitted.  */

    void (*code_end) (void);

    /* Output an assembler pseudo-op to declare a library function name

       external.  */

    void (*external_libcall) (rtx);

    /* Output an assembler directive to mark decl live. This instructs

        linker to not dead code strip this symbol.  */

    void (*mark_decl_preserved) (const char *);

    /* Output a record of the command line switches that have been passed.  */

    print_switch_fn_type record_gcc_switches;

    /* The name of the section that the example ELF implementation of

       record_gcc_switches will use to store the information.  Target

       specific versions of record_gcc_switches may or may not use

       this information.  */

    const char * record_gcc_switches_section;

    /* Output the definition of a section anchor.  */

    void (*output_anchor) (rtx);

    /* Output a DTP-relative reference to a TLS symbol.  */

    void (*output_dwarf_dtprel) (FILE *file, int size, rtx x);

    /* Some target machines need to postscan each insn after it is output.  */

    void (*final_postscan_insn) (FILE *, rtx, rtx *, int);

    /* Emit the trampoline template.  This hook may be NULL.  */

    void (*trampoline_template) (FILE *);

  } asm_out;

  /* Functions relating to instruction scheduling.  */

  struct sched

  {

    /* Given the current cost, COST, of an insn, INSN, calculate and

       return a new cost based on its relationship to DEP_INSN through

       the dependence LINK.  The default is to make no adjustment.  */

    int (* adjust_cost) (rtx insn, rtx link, rtx dep_insn, int cost);

    /* Adjust the priority of an insn as you see fit.  Returns the new

       priority.  */

    int (* adjust_priority) (rtx, int);

    /* Function which returns the maximum number of insns that can be

       scheduled in the same machine cycle.  This must be constant

       over an entire compilation.  The default is 1.  */

    int (* issue_rate) (void);

    /* Calculate how much this insn affects how many more insns we

       can emit this cycle.  Default is they all cost the same.  */

    int (* variable_issue) (FILE *, int, rtx, int);

    /* Initialize machine-dependent scheduling code.  */

    void (* md_init) (FILE *, int, int);

    /* Finalize machine-dependent scheduling code.  */

    void (* md_finish) (FILE *, int);

    /* Initialize machine-dependent function wide scheduling code.  */

    void (* md_init_global) (FILE *, int, int);

    /* Finalize machine-dependent function wide scheduling code.  */

    void (* md_finish_global) (FILE *, int);

    /* Reorder insns in a machine-dependent fashion, in two different

       places.  Default does nothing.  */

    int (* reorder) (FILE *, int, rtx *, int *, int);

    int (* reorder2) (FILE *, int, rtx *, int *, int);

    /* The following member value is a pointer to a function called

       after evaluation forward dependencies of insns in chain given

       by two parameter values (head and tail correspondingly).  */

    void (* dependencies_evaluation_hook) (rtx, rtx);

    /* The values of the following four members are pointers to

       functions used to simplify the automaton descriptions.

       dfa_pre_cycle_insn and dfa_post_cycle_insn give functions

       returning insns which are used to change the pipeline hazard

       recognizer state when the new simulated processor cycle

       correspondingly starts and finishes.  The function defined by

       init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used

       to initialize the corresponding insns.  The default values of

       the members result in not changing the automaton state when

       the new simulated processor cycle correspondingly starts and

       finishes.  */

    void (* init_dfa_pre_cycle_insn) (void);

    rtx (* dfa_pre_cycle_insn) (void);

    void (* init_dfa_post_cycle_insn) (void);

    rtx (* dfa_post_cycle_insn) (void);

    /* The values of the following two members are pointers to

       functions used to simplify the automaton descriptions.

       dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called

       immediately before and after cycle is advanced.  */

    void (* dfa_pre_advance_cycle) (void);

    void (* dfa_post_advance_cycle) (void);

    /* The following member value is a pointer to a function returning value

       which defines how many insns in queue `ready' will we try for

       multi-pass scheduling.  If the member value is nonzero and the

       function returns positive value, the DFA based scheduler will make

       multi-pass scheduling for the first cycle.  In other words, we will

       try to choose ready insn which permits to start maximum number of

       insns on the same cycle.  */

    int (* first_cycle_multipass_dfa_lookahead) (void);

    /* The following member value is pointer to a function controlling

       what insns from the ready insn queue will be considered for the

       multipass insn scheduling.  If the hook returns zero for insn

       passed as the parameter, the insn will be not chosen to be

       issued.  */

    int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);

    /* The following member value is pointer to a function called by

       the insn scheduler before issuing insn passed as the third

       parameter on given cycle.  If the hook returns nonzero, the

       insn is not issued on given processors cycle.  Instead of that,

       the processor cycle is advanced.  If the value passed through

       the last parameter is zero, the insn ready queue is not sorted

       on the new cycle start as usually.  The first parameter passes

       file for debugging output.  The second one passes the scheduler

       verbose level of the debugging output.  The forth and the fifth

       parameter values are correspondingly processor cycle on which

       the previous insn has been issued and the current processor

       cycle.  */

    int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);

    /* The following member value is a pointer to a function called by the

       insn scheduler.  It should return true if there exists a dependence

       which is considered costly by the target, between the insn

       DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP).  The first parameter is

       the dep that represents the dependence between the two insns.  The

       second argument is the cost of the dependence as estimated by

       the scheduler.  The last argument is the distance in cycles

       between the already scheduled insn (first parameter) and the

       second insn (second parameter).  */

    bool (* is_costly_dependence) (struct _dep *_dep, int, int);

    /* Given the current cost, COST, of an insn, INSN, calculate and

       return a new cost based on its relationship to DEP_INSN through the

       dependence of type DEP_TYPE.  The default is to make no adjustment.  */

    int (* adjust_cost_2) (rtx insn, int, rtx dep_insn, int cost, int dw);

    /* The following member value is a pointer to a function called

       by the insn scheduler. This hook is called to notify the backend

       that new instructions were emitted.  */

    void (* h_i_d_extended) (void);

    /* Next 5 functions are for multi-point scheduling.  */

    /* Allocate memory for scheduler context.  */

    void *(* alloc_sched_context) (void);

    /* Fills the context from the local machine scheduler context.  */

    void (* init_sched_context) (void *, bool);

    /* Sets local machine scheduler context to a saved value.  */

    void (* set_sched_context) (void *);

    /* Clears a scheduler context so it becomes like after init.  */

    void (* clear_sched_context) (void *);

    /* Frees the scheduler context.  */

    void (* free_sched_context) (void *);

    /* The following member value is a pointer to a function called

       by the insn scheduler.

       The first parameter is an instruction, the second parameter is the type

       of the requested speculation, and the third parameter is a pointer to the

       speculative pattern of the corresponding type (set if return value == 1).

       It should return

       -1, if there is no pattern, that will satisfy the requested speculation

       type,

       0, if current pattern satisfies the requested speculation type,

       1, if pattern of the instruction should be changed to the newly

       generated one.  */

    int (* speculate_insn) (rtx, int, rtx *);

    /* The following member value is a pointer to a function called

       by the insn scheduler.  It should return true if the check instruction

       passed as the parameter needs a recovery block.  */

    bool (* needs_block_p) (int);

    /* The following member value is a pointer to a function called

       by the insn scheduler.  It should return a pattern for the check

       instruction.

       The first parameter is a speculative instruction, the second parameter

       is the label of the corresponding recovery block (or null, if it is a

       simple check).  If the mutation of the check is requested (e.g. from

       ld.c to chk.a), the third parameter is true - in this case the first

       parameter is the previous check.  */

    rtx (* gen_spec_check) (rtx, rtx, int);

    /* The following member value is a pointer to a function controlling

       what insns from the ready insn queue will be considered for the

       multipass insn scheduling.  If the hook returns zero for the insn

       passed as the parameter, the insn will not be chosen to be

       issued.  This hook is used to discard speculative instructions,

       that stand at the first position of the ready list.  */

    bool (* first_cycle_multipass_dfa_lookahead_guard_spec) (const_rtx);

    /* The following member value is a pointer to a function that provides

       information about the speculation capabilities of the target.

       The parameter is a pointer to spec_info variable.  */

    void (* set_sched_flags) (struct spec_info_def *);

    /* Return speculation types of the instruction passed as the parameter.  */

    int (* get_insn_spec_ds) (rtx);

    /* Return speculation types that are checked for the instruction passed as

       the parameter.  */

    int (* get_insn_checked_ds) (rtx);

    /* Return bool if rtx scanning should just skip current layer and

       advance to the inner rtxes.  */

    bool (* skip_rtx_p) (const_rtx);

    /* The following member value is a pointer to a function that provides

       information about the target resource-based lower bound which is

       used by the swing modulo scheduler.  The parameter is a pointer

       to ddg variable.  */

    int (* sms_res_mii) (struct ddg *);

  } sched;

  /* Functions relating to vectorization.  */

  struct vectorize

  {

    /* The following member value is a pointer to a function called

       by the vectorizer, and return the decl of the target builtin

       function.  */

    tree (* builtin_mask_for_load) (void);

    /* Returns a code for builtin that realizes vectorized version of

       function, or NULL_TREE if not available.  */

    tree (* builtin_vectorized_function) (tree, tree, tree);

    /* Returns a code for builtin that realizes vectorized version of

       conversion, or NULL_TREE if not available.  */

    tree (* builtin_conversion) (unsigned, tree);

    /* Target builtin that implements vector widening multiplication.

       builtin_mul_widen_eve computes the element-by-element products

       for the even elements, and builtin_mul_widen_odd computes the

       element-by-element products for the odd elements.  */

    tree (* builtin_mul_widen_even) (tree);

    tree (* builtin_mul_widen_odd) (tree);

    /* Returns the cost to be added to the overheads involved with

       executing the vectorized version of a loop.  */

    int (*builtin_vectorization_cost) (bool);

    /* Return true if vector alignment is reachable (by peeling N

       iterations) for the given type.  */

    bool (* vector_alignment_reachable) (const_tree, bool);

    /* Target builtin that implements vector permute.  */

    tree (* builtin_vec_perm) (tree, tree*);

    /* Return true if a vector created for builtin_vec_perm is valid.  */

    bool (* builtin_vec_perm_ok) (tree, tree);

    /* Return true if the target supports misaligned store/load of a

       specific factor denoted in the third parameter.  The last parameter

       is true if the access is defined in a packed struct.  */

    bool (* builtin_support_vector_misalignment) (enum machine_mode,

                                                  const_tree, int, bool);

  } vectorize;

  /* The initial value of target_flags.  */

  int default_target_flags;

  /* Allow target specific overriding of option settings after options have

     been changed by an attribute or pragma or when it is reset at the

     end of the code affected by an attribute or pragma.  */

  void (* override_options_after_change) (void);

  /* Handle target switch CODE (an OPT_* value).  ARG is the argument

     passed to the switch; it is NULL if no argument was.  VALUE is the

     value of ARG if CODE specifies a UInteger option, otherwise it is

     1 if the positive form of the switch was used and 0 if the negative

     form was.  Return true if the switch was valid.  */

  bool (* handle_option) (size_t code, const char *arg, int value);

  /* Display extra, target specific information in response to a

     --target-help switch.  */

  void (* target_help) (void);

  /* Return machine mode for filter value.  */

  enum machine_mode (* eh_return_filter_mode) (void);

  /* Return machine mode for libgcc expanded cmp instructions.  */

  enum machine_mode (* libgcc_cmp_return_mode) (void);

  /* Return machine mode for libgcc expanded shift instructions.  */

  enum machine_mode (* libgcc_shift_count_mode) (void);

  /* Return machine mode to be used for _Unwind_Word type.  */

  enum machine_mode (* unwind_word_mode) (void);

  /* Given two decls, merge their attributes and return the result.  */

  tree (* merge_decl_attributes) (tree, tree);

  /* Given two types, merge their attributes and return the result.  */

  tree (* merge_type_attributes) (tree, tree);

  /* Table of machine attributes and functions to handle them.

     Ignored if NULL.  */

  const struct attribute_spec *attribute_table;

  /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,

     one if they are compatible and two if they are nearly compatible

     (which causes a warning to be generated).  */

  int (* comp_type_attributes) (const_tree type1, const_tree type2);

  /* Assign default attributes to the newly defined TYPE.  */

  void (* set_default_type_attributes) (tree type);

  /* Insert attributes on the newly created DECL.  */

  void (* insert_attributes) (tree decl, tree *attributes);

  /* Return true if FNDECL (which has at least one machine attribute)

     can be inlined despite its machine attributes, false otherwise.  */

  bool (* function_attribute_inlinable_p) (const_tree fndecl);

  /* Return true if bitfields in RECORD_TYPE should follow the

     Microsoft Visual C++ bitfield layout rules.  */

  bool (* ms_bitfield_layout_p) (const_tree record_type);

  /* True if the target supports decimal floating point.  */

  bool (* decimal_float_supported_p) (void);

  /* True if the target supports fixed-point.  */

  bool (* fixed_point_supported_p) (void);

  /* Return true if anonymous bitfields affect structure alignment.  */

  bool (* align_anon_bitfield) (void);

  /* Return true if volatile bitfields should use the narrowest type possible.

     Return false if they should use the container type.  */

  bool (* narrow_volatile_bitfield) (void);

  /* Set up target-specific built-in functions.  */

  void (* init_builtins) (void);

  /* Initialize (if INITIALIZE_P is true) and return the target-specific

     built-in function decl for CODE.

     Return NULL if that is not possible.  Return error_mark_node if CODE

     is outside of the range of valid target builtin function codes.  */

  tree (* builtin_decl) (unsigned code, bool initialize_p);

  /* Expand a target-specific builtin.  */

  rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,

                          enum machine_mode mode, int ignore);

  /* Select a replacement for a target-specific builtin.  This is done

     *before* regular type checking, and so allows the target to

     implement a crude form of function overloading.  The result is a

     complete expression that implements the operation.  PARAMS really

     has type VEC(tree,gc)*, but we don't want to include tree.h

     here.  */

  tree (*resolve_overloaded_builtin) (unsigned int /*location_t*/,

                                      tree decl, void *params);

  /* Fold a target-specific builtin.  */

  tree (* fold_builtin) (tree fndecl, tree arglist, bool ignore);

  /* Returns a code for a target-specific builtin that implements

     reciprocal of the function, or NULL_TREE if not available.  */

  tree (* builtin_reciprocal) (unsigned, bool, bool);

  /* For a vendor-specific TYPE, return a pointer to a statically-allocated

     string containing the C++ mangling for TYPE.  In all other cases, return

     NULL.  */

  const char * (* mangle_type) (const_tree type);

  /* Make any adjustments to libfunc names needed for this target.  */

  void (* init_libfuncs) (void);

  /* Given a decl, a section name, and whether the decl initializer

     has relocs, choose attributes for the section.  */

  /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION.  */

  unsigned int (* section_type_flags) (tree, const char *, int);

  /* True if new jumps cannot be created, to replace existing ones or

     not, at the current point in the compilation.  */

  bool (* cannot_modify_jumps_p) (void);

  /* Return a register class for which branch target register

     optimizations should be applied.  */

  enum reg_class (* branch_target_register_class) (void);

  /* Return true if branch target register optimizations should include

     callee-saved registers that are not already live during the current

     function.  AFTER_PE_GEN is true if prologues and epilogues have

     already been generated.  */

  bool (* branch_target_register_callee_saved) (bool after_pe_gen);

  /* Return true if the target supports conditional execution.  */

  bool (* have_conditional_execution) (void);

  /* True if the constant X cannot be placed in the constant pool.  */

  bool (* cannot_force_const_mem) (rtx);

  /* True if the insn X cannot be duplicated.  */

  bool (* cannot_copy_insn_p) (rtx);

  /* True if X is considered to be commutative.  */

  bool (* commutative_p) (const_rtx, int);

  /* Given an invalid address X for a given machine mode, try machine-specific

     ways to make it legitimate.  Return X or an invalid address on failure.  */

  rtx (* legitimize_address) (rtx, rtx, enum machine_mode);

  /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS.  */

  rtx (* delegitimize_address) (rtx);

  /* Given an address RTX, say whether it is valid.  */

  bool (* legitimate_address_p) (enum machine_mode, rtx, bool);

  /* True if the given constant can be put into an object_block.  */

  bool (* use_blocks_for_constant_p) (enum machine_mode, const_rtx);

  /* The minimum and maximum byte offsets for anchored addresses.  */

  HOST_WIDE_INT min_anchor_offset;

  HOST_WIDE_INT max_anchor_offset;

  /* True if section anchors can be used to access the given symbol.  */

  bool (* use_anchors_for_symbol_p) (const_rtx);

  /* True if it is OK to do sibling call optimization for the specified

     call expression EXP.  DECL will be the called function, or NULL if

     this is an indirect call.  */

  bool (*function_ok_for_sibcall) (tree decl, tree exp);

  /* Establish appropriate back-end context for processing the function

     FNDECL.  The argument might be NULL to indicate processing at top

     level, outside of any function scope.  */

  void (*set_current_function) (tree fndecl);

  /* True if EXP should be placed in a "small data" section.  */

  bool (* in_small_data_p) (const_tree);

  /* True if EXP names an object for which name resolution must resolve

     to the current executable or shared library.  */

  bool (* binds_local_p) (const_tree);

  /* Modify and return the identifier of a DECL's external name,

     originally identified by ID, as required by the target,

    (eg, append @nn to windows32 stdcall function names).

     The default is to return ID without modification. */

   tree (* mangle_decl_assembler_name) (tree decl, tree  id);

  /* Do something target-specific to record properties of the DECL into

     the associated SYMBOL_REF.  */

  void (* encode_section_info) (tree, rtx, int);

  /* Undo the effects of encode_section_info on the symbol string.  */

  const char * (* strip_name_encoding) (const char *);

  /* If shift optabs for MODE are known to always truncate the shift count,

     return the mask that they apply.  Return 0 otherwise.  */

  unsigned HOST_WIDE_INT (* shift_truncation_mask) (enum machine_mode mode);

  /* Return the number of divisions in the given MODE that should be present,

     so that it is profitable to turn the division into a multiplication by

     the reciprocal.  */

  unsigned int (* min_divisions_for_recip_mul) (enum machine_mode mode);

  /* If the representation of integral MODE is such that values are

     always sign-extended to a wider mode MODE_REP then return

     SIGN_EXTEND.  Return UNKNOWN otherwise.  */

  /* Note that the return type ought to be RTX_CODE, but that's not

     necessarily defined at this point.  */

  int (* mode_rep_extended) (enum machine_mode mode,

                             enum machine_mode mode_rep);

  /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))).  */

  bool (* valid_pointer_mode) (enum machine_mode mode);

  /* Support for named address spaces.  */

  struct addr_space {

    /* MODE to use for a pointer into another address space.  */

    enum machine_mode (* pointer_mode) (addr_space_t);

    /* MODE to use for an address in another address space.  */

    enum machine_mode (* address_mode) (addr_space_t);