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[gcc.git] / gcc / target.def

/* Target hook definitions.
   Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   2011, 2012
   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!  */

/* See target-hooks-macros.h for details of macros that should be
   provided by the including file, and how to use them here.  */
#include "target-hooks-macros.h"

#undef HOOK_TYPE
#define HOOK_TYPE "Target Hook"

HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)

/* Functions that output assembler for the target.  */
#define HOOK_PREFIX "TARGET_ASM_"
HOOK_VECTOR (TARGET_ASM_OUT, asm_out)

/* Opening and closing parentheses for asm expression grouping.  */
DEFHOOKPOD
(open_paren,
 "",
 const char *, "(")
DEFHOOKPODX (close_paren, const char *, ")")

/* Assembler instructions for creating various kinds of integer object.  */
DEFHOOKPOD
(byte_op,
 "",
 const char *, "\t.byte\t")
DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)

/* The maximum number of bytes to skip when applying
   LABEL_ALIGN_AFTER_BARRIER.  */
DEFHOOK
(label_align_after_barrier_max_skip,
 "",
 int, (rtx label),
 default_label_align_after_barrier_max_skip)

/* The maximum number of bytes to skip when applying
   LOOP_ALIGN.  */
DEFHOOK
(loop_align_max_skip,
 "",
 int, (rtx label),
 default_loop_align_max_skip)

/* The maximum number of bytes to skip when applying
   LABEL_ALIGN.  */
DEFHOOK
(label_align_max_skip,
 "",
 int, (rtx label),
 default_label_align_max_skip)

/* The maximum number of bytes to skip when applying
   JUMP_ALIGN.  */
DEFHOOK
(jump_align_max_skip,
 "",
 int, (rtx label),
 default_jump_align_max_skip)

/* 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.  */
DEFHOOK
(integer,
 "",
 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
    NULL.  */
 bool, (rtx x, unsigned int size, int aligned_p),
 default_assemble_integer)

/* Output code that will globalize a label.  */
DEFHOOK
(globalize_label,
 "",
 void, (FILE *stream, const char *name),
 default_globalize_label)

/* Output code that will globalize a declaration.  */
DEFHOOK
(globalize_decl_name,
 "",
 void, (FILE *stream, tree decl), default_globalize_decl_name)

/* 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.  */
DEFHOOK
(emit_unwind_label,
 "",
 void, (FILE *stream, tree decl, int for_eh, int empty),
 default_emit_unwind_label)

/* Output code that will emit a label to divide up the exception table.  */
DEFHOOK
(emit_except_table_label,
 "",
 void, (FILE *stream),
 default_emit_except_table_label)

/* Emit a directive for setting the personality for the function.  */
DEFHOOK
(emit_except_personality,
 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
 used to emit a directive to install a personality hook into the unwind\
 info.  This hook should not be used if dwarf2 unwind info is used.",
 void, (rtx personality),
 NULL)

/* Emit any directives required to unwind this instruction.  */
DEFHOOK
(unwind_emit,
 "",
 void, (FILE *stream, rtx insn),
 NULL)

DEFHOOKPOD
(unwind_emit_before_insn,
 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
 the assembly for @var{insn} has been emitted, false if the hook should\
 be called afterward.",
 bool, true)

/* Generate an internal label.
   For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL.  */
DEFHOOK_UNDOC
(generate_internal_label,
 "",
 void, (char *buf, const char *prefix, unsigned long labelno),
 default_generate_internal_label)

/* Output an internal label.  */
DEFHOOK
(internal_label,
 "",
 void, (FILE *stream, const char *prefix, unsigned long labelno),
 default_internal_label)

/* Output label for the constant.  */
DEFHOOK
(declare_constant_name,
 "",
 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
 default_asm_declare_constant_name)

/* Emit a ttype table reference to a typeinfo object.  */
DEFHOOK
(ttype,
 "",
 bool, (rtx sym),
 hook_bool_rtx_false)

/* Emit an assembler directive to set visibility for the symbol
   associated with the tree decl.  */
DEFHOOK
(assemble_visibility,
 "",
 void, (tree decl, int visibility),
 default_assemble_visibility)

/* Output the assembler code for entry to a function.  */
DEFHOOK
(function_prologue,
 "",
 void, (FILE *file, HOST_WIDE_INT size),
 default_function_pro_epilogue)

/* Output the assembler code for end of prologue.  */
DEFHOOK
(function_end_prologue,
 "",
 void, (FILE *file),
 no_asm_to_stream)

/* Output the assembler code for start of epilogue.  */
DEFHOOK
(function_begin_epilogue,
 "",
 void, (FILE *file),
 no_asm_to_stream)

/* Output the assembler code for function exit.  */
DEFHOOK
(function_epilogue,
 "",
 void, (FILE *file, HOST_WIDE_INT size),
 default_function_pro_epilogue)

/* Initialize target-specific sections.  */
DEFHOOK
(init_sections,
 "",
 void, (void),
 hook_void_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.  */
DEFHOOK
(named_section,
 "",
 void, (const char *name, unsigned int flags, tree decl),
 default_no_named_section)

/* Return preferred text (sub)section for function DECL.
   Main purpose of this function is to separate cold, normal and hot
   functions. STARTUP is true when function is known to be used only 
   at startup (from static constructors or it is main()).
   EXIT is true when function is known to be used only at exit
   (from static destructors).
   Return NULL if function should go to default text section.  */
DEFHOOK
(function_section,
 "",
 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
 default_function_section)

/* Output the assembler code for function exit.  */
DEFHOOK
(function_switched_text_sections,
 "Used by the target to emit any assembler directives or additional\
  labels needed when a function is partitioned between different\
  sections.  Output should be written to @var{file}.  The function\
  decl is available as @var{decl} and the new section is `cold' if\
  @var{new_is_cold} is @code{true}.",
 void, (FILE *file, tree decl, bool new_is_cold),
 default_function_switched_text_sections)

/* 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.  */
DEFHOOK
(reloc_rw_mask,
 "",
 int, (void),
 default_reloc_rw_mask)

 /* 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.  */
DEFHOOK
(select_section,
 "",
 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
 default_select_section)

/* Return a section for X.  MODE is X's mode and ALIGN is its
   alignment in bits.  */
DEFHOOK
(select_rtx_section,
 "",
 section *, (enum machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
 default_select_rtx_section)

/* Select a unique section name for DECL.  RELOC is the same as
   for SELECT_SECTION.  */
DEFHOOK
(unique_section,
 "",
 void, (tree decl, int reloc),
 default_unique_section)

/* Return the readonly data section associated with function DECL.  */
DEFHOOK
(function_rodata_section,
 "",
 section *, (tree decl),
 default_function_rodata_section)

/* Nonnull if the target wants to override the default ".rodata" prefix
   for mergeable data sections.  */
DEFHOOKPOD
(mergeable_rodata_prefix,
 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
section names for mergeable constant data.  Define this macro to override\n\
the string if a different section name should be used.",
 const char *, ".rodata")

/* Return the section to be used for transactional memory clone tables.  */
DEFHOOK
(tm_clone_table_section,
 "Return the section that should be used for transactional memory clone\
  tables.",
 section *, (void), default_clone_table_section)

/* Output a constructor for a symbol with a given priority.  */
DEFHOOK
(constructor,
 "",
 void, (rtx symbol, int priority), NULL)

/* Output a destructor for a symbol with a given priority.  */
DEFHOOK
(destructor,
 "",
 void, (rtx symbol, int priority), NULL)

/* 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.  */
DEFHOOK
(output_mi_thunk,
 "",
 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
        HOST_WIDE_INT vcall_offset, tree function),
 NULL)

/* 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.  */
DEFHOOK
(can_output_mi_thunk,
 "",
 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
        HOST_WIDE_INT vcall_offset, const_tree function),
 hook_bool_const_tree_hwi_hwi_const_tree_false)

/* Output any boilerplate text needed at the beginning of a
   translation unit.  */
DEFHOOK
(file_start,
 "",
 void, (void),
 default_file_start)

/* Output any boilerplate text needed at the end of a translation unit.  */
DEFHOOK
(file_end,
 "",
 void, (void),
 hook_void_void)

/* Output any boilerplate text needed at the beginning of an
   LTO output stream.  */
DEFHOOK
(lto_start,
 "",
 void, (void),
 hook_void_void)

/* Output any boilerplate text needed at the end of an
   LTO output stream.  */
DEFHOOK
(lto_end,
 "",
 void, (void),
 hook_void_void)

/* Output any boilerplace text needed at the end of a
   translation unit before debug and unwind info is emitted.  */
DEFHOOK
(code_end,
 "",
 void, (void),
 hook_void_void)

/* Output an assembler pseudo-op to declare a library function name
   external.  */
DEFHOOK
(external_libcall,
 "",
 void, (rtx symref),
 default_external_libcall)

/* Output an assembler directive to mark decl live. This instructs
   linker to not dead code strip this symbol.  */
DEFHOOK
(mark_decl_preserved,
 "",
 void, (const char *symbol),
 hook_void_constcharptr)

/* Output a record of the command line switches that have been passed.  */
DEFHOOK
(record_gcc_switches,
 "",
 int, (print_switch_type type, const char *text),
 NULL)

/* 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.  */
DEFHOOKPOD
(record_gcc_switches_section,
 "",
 const char *, ".GCC.command.line")

/* Output the definition of a section anchor.  */
DEFHOOK
(output_anchor,
 "",
 void, (rtx x),
 default_asm_output_anchor)

DEFHOOK
(output_ident,
 "Output a string based on @var{name}, suitable for the @samp{#ident} \
 directive, or the equivalent directive or pragma in non-C-family languages. \
 If this hook is not defined, nothing is output for the @samp{#ident} \
 directive.",
 void, (const char *name),
 hook_void_constcharptr)

/* Output a DTP-relative reference to a TLS symbol.  */
DEFHOOK
(output_dwarf_dtprel,
 "",
 void, (FILE *file, int size, rtx x),
 NULL)

/* Some target machines need to postscan each insn after it is output.  */
DEFHOOK
(final_postscan_insn,
 "",
 void, (FILE *file, rtx insn, rtx *opvec, int noperands),
 NULL)

/* Emit the trampoline template.  This hook may be NULL.  */
DEFHOOK
(trampoline_template,
 "",
 void, (FILE *f),
 NULL)

DEFHOOK
(output_source_filename,
 "Output COFF information or DWARF debugging information which indicates\
 that filename @var{name} is the current source file to the stdio\
 stream @var{file}.\n\
 \n\
 This target hook need not be defined if the standard form of output\
 for the file format in use is appropriate.",
 void ,(FILE *file, const char *name),
 default_asm_output_source_filename)

DEFHOOK
(output_addr_const_extra,
 "",
 bool, (FILE *file, rtx x),
 hook_bool_FILEptr_rtx_false)

/* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
   even though that is not reflected in the macro name to override their
   initializers.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_"

/* Emit a machine-specific insn operand.  */
/* ??? tm.texi only documents the old macro PRINT_OPERAND,
   not this  hook, and uses a different name for the argument FILE.  */
DEFHOOK_UNDOC
(print_operand,
 "",
 void, (FILE *file, rtx x, int code),
 default_print_operand)

/* Emit a machine-specific memory address.  */
/* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
   not this  hook, and uses different argument names.  */
DEFHOOK_UNDOC
(print_operand_address,
 "",
 void, (FILE *file, rtx addr),
 default_print_operand_address)

/* Determine whether CODE is a valid punctuation character for the
   `print_operand' hook.  */
/* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
   not this  hook.  */
DEFHOOK_UNDOC
(print_operand_punct_valid_p,
 "",
 bool ,(unsigned char code),
 default_print_operand_punct_valid_p)

/* Given a symbol name, perform same mangling as assemble_name and
   ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE.  */
DEFHOOK
(mangle_assembler_name,
 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
 @code{assemble_name}, but in memory rather than to a file stream, returning\
 result as an @code{IDENTIFIER_NODE}.  Required for correct LTO symtabs.  The\
 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
 then prepends the @code{USER_LABEL_PREFIX}, if any.",
 tree, (const char *name),
 default_mangle_assembler_name)

HOOK_VECTOR_END (asm_out)

/* Functions relating to instruction scheduling.  All of these
   default to null pointers, which haifa-sched.c looks for and handles.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_SCHED_"
HOOK_VECTOR (TARGET_SCHED, 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.  */
DEFHOOK
(adjust_cost,
 "",
 int, (rtx insn, rtx link, rtx dep_insn, int cost), NULL)

/* Adjust the priority of an insn as you see fit.  Returns the new priority.  */
DEFHOOK
(adjust_priority,
 "",
 int, (rtx insn, int priority), NULL)

/* 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.  */
DEFHOOK
(issue_rate,
 "",
 int, (void), NULL)

/* Calculate how much this insn affects how many more insns we
   can emit this cycle.  Default is they all cost the same.  */
DEFHOOK
(variable_issue,
 "",
 int, (FILE *file, int verbose, rtx insn, int more), NULL)

/* Initialize machine-dependent scheduling code.  */
DEFHOOK
(init,
 "",
 void, (FILE *file, int verbose, int max_ready), NULL)

/* Finalize machine-dependent scheduling code.  */
DEFHOOK
(finish,
 "",
 void, (FILE *file, int verbose), NULL)

 /* Initialize machine-dependent function wide scheduling code.  */
DEFHOOK
(init_global,
 "",
 void, (FILE *file, int verbose, int old_max_uid), NULL)

/* Finalize machine-dependent function wide scheduling code.  */
DEFHOOK
(finish_global,
 "",
 void, (FILE *file, int verbose), NULL)

/* Reorder insns in a machine-dependent fashion, in two different
       places.  Default does nothing.  */
DEFHOOK
(reorder,
 "",
 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)

DEFHOOK
(reorder2,
 "",
 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)

/* 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).  */
DEFHOOK
(dependencies_evaluation_hook,
 "",
 void, (rtx head, rtx tail), NULL)

/* 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.  */

DEFHOOK
(init_dfa_pre_cycle_insn,
 "",
 void, (void), NULL)

DEFHOOK
(dfa_pre_cycle_insn,
 "",
 rtx, (void), NULL)

DEFHOOK
(init_dfa_post_cycle_insn,
 "",
 void, (void), NULL)

DEFHOOK
(dfa_post_cycle_insn,
 "",
 rtx, (void), NULL)

/* 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.  */

DEFHOOK
(dfa_pre_advance_cycle,
 "",
 void, (void), NULL)

DEFHOOK
(dfa_post_advance_cycle,
 "",
 void, (void), NULL)

/* 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.  */
DEFHOOK
(first_cycle_multipass_dfa_lookahead,
 "",
 int, (void), NULL)

/* 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.  */
DEFHOOK
(first_cycle_multipass_dfa_lookahead_guard,
 "",
 int, (rtx insn), NULL)

/* This hook prepares the target for a new round of multipass
   scheduling.
   DATA is a pointer to target-specific data used for multipass scheduling.
   READY_TRY and N_READY represent the current state of search in the
   optimization space.  The target can filter out instructions that
   should not be tried during current round by setting corresponding
   elements in READY_TRY to non-zero.
   FIRST_CYCLE_INSN_P is true if this is the first round of multipass
   scheduling on current cycle.  */
DEFHOOK
(first_cycle_multipass_begin,
 "",
 void, (void *data, char *ready_try, int n_ready, bool first_cycle_insn_p),
 NULL)

/* This hook is called when multipass scheduling evaluates instruction INSN.
   DATA is a pointer to target-specific data that can be used to record effects
   of INSN on CPU that are not described in DFA.
   READY_TRY and N_READY represent the current state of search in the
   optimization space.  The target can filter out instructions that
   should not be tried after issuing INSN by setting corresponding
   elements in READY_TRY to non-zero.
   INSN is the instruction being evaluated.
   PREV_DATA is a pointer to target-specific data corresponding
   to a state before issuing INSN.  */
DEFHOOK
(first_cycle_multipass_issue,
 "",
 void, (void *data, char *ready_try, int n_ready, rtx insn,
        const void *prev_data), NULL)

/* This hook is called when multipass scheduling backtracks from evaluation of
   instruction corresponding to DATA.
   DATA is a pointer to target-specific data that stores the effects
   of instruction from which the algorithm backtracks on CPU that are not
   described in DFA.
   READY_TRY and N_READY represent the current state of search in the
   optimization space.  The target can filter out instructions that
   should not be tried after issuing INSN by setting corresponding
   elements in READY_TRY to non-zero.  */
DEFHOOK
(first_cycle_multipass_backtrack,
 "",
 void, (const void *data, char *ready_try, int n_ready), NULL)

/* This hook notifies the target about the result of the concluded current
   round of multipass scheduling.
   DATA is a pointer.
   If DATA is non-NULL it points to target-specific data used for multipass
   scheduling which corresponds to instruction at the start of the chain of
   the winning solution.  DATA is NULL when multipass scheduling cannot find
   a good enough solution on current cycle and decides to retry later,
   usually after advancing the cycle count.  */
DEFHOOK
(first_cycle_multipass_end,
 "",
 void, (const void *data), NULL)

/* This hook is called to initialize target-specific data for multipass
   scheduling after it has been allocated.
   DATA is a pointer to target-specific data that stores the effects
   of instruction from which the algorithm backtracks on CPU that are not
   described in DFA.  */
DEFHOOK
(first_cycle_multipass_init,
 "",
 void, (void *data), NULL)

/* This hook is called to finalize target-specific data for multipass
   scheduling before it is deallocated.
   DATA is a pointer to target-specific data that stores the effects
   of instruction from which the algorithm backtracks on CPU that are not
   described in DFA.  */
DEFHOOK
(first_cycle_multipass_fini,
 "",
 void, (void *data), NULL)

/* 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.  */
DEFHOOK
(dfa_new_cycle,
 "",
 int, (FILE *dump, int verbose, rtx insn, int last_clock,
       int clock, int *sort_p),
 NULL)

/* 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).  */
DEFHOOK
(is_costly_dependence,
 "",
 bool, (struct _dep *_dep, int cost, int distance), NULL)

DEFHOOK_UNDOC
(adjust_cost_2,
 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
 return a new cost based on its relationship to @var{dep_insn} through the\
 dependence of weakness @var{dw}.  The default is to make no adjustment.",
 int, (rtx insn, int dep_type1, rtx dep_insn, int cost, int dw), NULL)

/* 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.  */
DEFHOOK
(h_i_d_extended,
 "",
 void, (void), NULL)

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

/* Allocate memory for scheduler context.  */
DEFHOOK
(alloc_sched_context,
 "",
 void *, (void), NULL)

/* Fills the context from the local machine scheduler context.  */
DEFHOOK
(init_sched_context,
 "",
 void, (void *tc, bool clean_p), NULL)

/* Sets local machine scheduler context to a saved value.  */
DEFHOOK
(set_sched_context,
 "",
 void, (void *tc), NULL)

/* Clears a scheduler context so it becomes like after init.  */
DEFHOOK
(clear_sched_context,
 "",
 void, (void *tc), NULL)

/* Frees the scheduler context.  */
DEFHOOK
(free_sched_context,
 "",
 void, (void *tc), NULL)

/* 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.  */
DEFHOOK
(speculate_insn,
 "",
 int, (rtx insn, int request, rtx *new_pat), NULL)

/* 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.  */
DEFHOOK
(needs_block_p,
 "",
 bool, (int dep_status), NULL)

/* 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.  */
DEFHOOK
(gen_spec_check,
 "",
 rtx, (rtx insn, rtx label, int mutate_p), NULL)

/* 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.  */
DEFHOOK
(first_cycle_multipass_dfa_lookahead_guard_spec,
 "",
 bool, (const_rtx insn), NULL)

/* 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.  */
DEFHOOK
(set_sched_flags,
 "",
 void, (struct spec_info_def *spec_info), NULL)

DEFHOOK_UNDOC
(get_insn_spec_ds,
 "Return speculation types of instruction @var{insn}.",
 int, (rtx insn), NULL)

DEFHOOK_UNDOC
(get_insn_checked_ds,
 "Return speculation types that are checked for instruction @var{insn}",
 int, (rtx insn), NULL)

DEFHOOK_UNDOC
(skip_rtx_p,
 "Return bool if rtx scanning should just skip current layer and\
 advance to the inner rtxes.",
 bool, (const_rtx x), NULL)

/* 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.  */
DEFHOOK
(sms_res_mii,
 "",
 int, (struct ddg *g), NULL)

/* The following member value is a function that initializes dispatch
   schedling and adds instructions to dispatch window according to its
   parameters.  */
DEFHOOK
(dispatch_do,
"",
void, (rtx insn, int x),
hook_void_rtx_int)

/* The following member value is a a function that returns true is
   dispatch schedling is supported in hardware and condition passed
   as the second parameter is true.  */
DEFHOOK
(dispatch,
"",
bool, (rtx insn, int x),
hook_bool_rtx_int_false)

DEFHOOKPOD
(exposed_pipeline,
"True if the processor has an exposed pipeline, which means that not just\n\
the order of instructions is important for correctness when scheduling, but\n\
also the latencies of operations.",
bool, false)

/* The following member value is a function that returns number
   of operations reassociator should try to put in parallel for
   statements of the given type.  By default 1 is used.  */
DEFHOOK
(reassociation_width,
"This hook is called by tree reassociator to determine a level of\n\
parallelism required in output calculations chain.",
int, (unsigned int opc, enum machine_mode mode),
hook_int_uint_mode_1)

HOOK_VECTOR_END (sched)

/* Functions relating to vectorization.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_VECTORIZE_"
HOOK_VECTOR (TARGET_VECTORIZE, vectorize)

/* The following member value is a pointer to a function called
   by the vectorizer, and return the decl of the target builtin
   function.  */
DEFHOOK
(builtin_mask_for_load,
 "",
 tree, (void), NULL)

/* Returns a code for builtin that realizes vectorized version of
   function, or NULL_TREE if not available.  */
DEFHOOK
(builtin_vectorized_function,
 "",
 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
 default_builtin_vectorized_function)

/* Returns a function declaration for a builtin that realizes the
   vector conversion, or NULL_TREE if not available.  */
DEFHOOK
(builtin_conversion,
 "",
 tree, (unsigned code, tree dest_type, tree src_type),
 default_builtin_vectorized_conversion)

/* Cost of different vector/scalar statements in vectorization cost
   model. In case of misaligned vector loads and stores the cost depends
   on the data type and misalignment value.  */
DEFHOOK
(builtin_vectorization_cost,
 "",
 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
 default_builtin_vectorization_cost)

/* Return true if vector alignment is reachable (by peeling N
   iterations) for the given type.  */
DEFHOOK
(vector_alignment_reachable,
 "",
 bool, (const_tree type, bool is_packed),
 default_builtin_vector_alignment_reachable)

/* Return true if a vector created for vec_perm_const is valid.
   A NULL indicates that all constants are valid permutations.  */
DEFHOOK
(vec_perm_const_ok,
 "",
 bool, (enum machine_mode, const unsigned char *sel),
 NULL)

/* 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.  */
DEFHOOK
(support_vector_misalignment,
 "",
 bool,
 (enum machine_mode mode, const_tree type, int misalignment, bool is_packed),
 default_builtin_support_vector_misalignment)

/* Return the builtin decl needed to load a vector of TYPE.  */
DEFHOOK
(builtin_tm_load,
 "This hook should return the built-in decl needed to load a vector of the "
 "given type within a transaction.",
 tree,
 (tree),
 default_builtin_tm_load_store)

/* Return the builtin decl needed to store a vector of TYPE.  */
DEFHOOK
(builtin_tm_store,
 "This hook should return the built-in decl needed to store a vector of the "
 "given type within a transaction.",
 tree,
 (tree),
 default_builtin_tm_load_store)

/* Returns the preferred mode for SIMD operations for the specified
   scalar mode.  */
DEFHOOK
(preferred_simd_mode,
 "",
 enum machine_mode,
 (enum machine_mode mode),
 default_preferred_simd_mode)

/* Returns a mask of vector sizes to iterate over when auto-vectorizing
   after processing the preferred one derived from preferred_simd_mode.  */
DEFHOOK
(autovectorize_vector_sizes,
 "",
 unsigned int,
 (void),
 default_autovectorize_vector_sizes)

/* Target builtin that implements vector gather operation.  */
DEFHOOK
(builtin_gather,
 "",
 tree,
 (const_tree mem_vectype, const_tree index_type, int scale),
 NULL)

/* Target function to initialize the cost model for a loop or block.  */
DEFHOOK
(init_cost,
 "This hook should initialize target-specific data structures in preparation "
 "for modeling the costs of vectorizing a loop or basic block.  The default "
 "allocates an unsigned integer for accumulating a single cost.  "
 "If @var{loop_info} is non-NULL, it identifies the loop being vectorized; "
 "otherwise a single block is being vectorized.",
 void *,
 (struct loop *loop_info),
 default_init_cost)

/* Target function to record N statements of the given kind using the
   given vector type within the cost model data for the current loop
   or block.  */
DEFHOOK
(add_stmt_cost,
 "This hook should update the target-specific @var{data} in response to "
 "adding @var{count} copies of the given @var{kind} of statement to the "
 "body of a loop or basic block.  The default adds the builtin vectorizer "
 "cost for the copies of the statement to the accumulator, and returns "
 "the amount added.  The return value should be viewed as a tentative "
 "cost that may later be overridden.",
 unsigned,
 (void *data, int count, enum vect_cost_for_stmt kind,
  struct _stmt_vec_info *stmt_info, int misalign),
 default_add_stmt_cost)

/* Target function to calculate the total cost of the current vectorized
   loop or block.  */
DEFHOOK
(finish_cost,
 "This hook should complete calculations of the cost of vectorizing a loop "
 "or basic block based on @var{data}, and return that cost as an unsigned "
 "integer.  The default returns the value of the accumulator.",
 unsigned,
 (void *data),
 default_finish_cost)

/* Function to delete target-specific cost modeling data.  */
DEFHOOK
(destroy_cost_data,
 "This hook should release @var{data} and any related data structures "
 "allocated by TARGET_VECTORIZE_INIT_COST.  The default releases the "
 "accumulator.",
 void,
 (void *data),
 default_destroy_cost_data)

HOOK_VECTOR_END (vectorize)

#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_"

/* 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.  */
DEFHOOK
(override_options_after_change,
 "",
 void, (void),
 hook_void_void)

DEFHOOK_UNDOC
(eh_return_filter_mode,
 "Return machine mode for filter value.",
 enum machine_mode, (void),
 default_eh_return_filter_mode)

/* Return machine mode for libgcc expanded cmp instructions.  */
DEFHOOK
(libgcc_cmp_return_mode,
 "",
 enum machine_mode, (void),
 default_libgcc_cmp_return_mode)

/* Return machine mode for libgcc expanded shift instructions.  */
DEFHOOK
(libgcc_shift_count_mode,
 "",
 enum machine_mode, (void),
 default_libgcc_shift_count_mode)

/* Return machine mode to be used for _Unwind_Word type.  */
DEFHOOK
(unwind_word_mode,
 "",
 enum machine_mode, (void),
 default_unwind_word_mode)

/* Given two decls, merge their attributes and return the result.  */
DEFHOOK
(merge_decl_attributes,
 "",
 tree, (tree olddecl, tree newdecl),
 merge_decl_attributes)

/* Given two types, merge their attributes and return the result.  */
DEFHOOK
(merge_type_attributes,
 "",
 tree, (tree type1, tree type2),
 merge_type_attributes)

/* Table of machine attributes and functions to handle them.
   Ignored if NULL.  */
DEFHOOKPOD
(attribute_table,
 "",
 const struct attribute_spec *, NULL)

/* Return true iff attribute NAME expects a plain identifier as its first
   argument.  */
DEFHOOK
(attribute_takes_identifier_p,
 "",
 bool, (const_tree name),
 hook_bool_const_tree_false)

/* 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).  */
DEFHOOK
(comp_type_attributes,
 "",
 int, (const_tree type1, const_tree type2),
 hook_int_const_tree_const_tree_1)

/* Assign default attributes to the newly defined TYPE.  */
DEFHOOK
(set_default_type_attributes,
 "",
 void, (tree type),
 hook_void_tree)

/* Insert attributes on the newly created DECL.  */
DEFHOOK
(insert_attributes,
 "",
 void, (tree node, tree *attr_ptr),
 hook_void_tree_treeptr)

/* Return true if FNDECL (which has at least one machine attribute)
   can be inlined despite its machine attributes, false otherwise.  */
DEFHOOK
(function_attribute_inlinable_p,
 "",
 bool, (const_tree fndecl),
 hook_bool_const_tree_false)

/* Return true if bitfields in RECORD_TYPE should follow the
   Microsoft Visual C++ bitfield layout rules.  */
DEFHOOK
(ms_bitfield_layout_p,
 "",
 bool, (const_tree record_type),
 hook_bool_const_tree_false)

/* For now this is only an interface to WORDS_BIG_ENDIAN for
   target-independent code like the front ends, need performance testing
   before switching completely to the target hook.  */
DEFHOOK_UNDOC
(words_big_endian,
 "",
 bool, (void),
 targhook_words_big_endian)

/* Likewise for FLOAT_WORDS_BIG_ENDIAN.  */
DEFHOOK_UNDOC
(float_words_big_endian,
 "",
 bool, (void),
 targhook_float_words_big_endian)

/* True if the target supports decimal floating point.  */
DEFHOOK
(decimal_float_supported_p,
 "",
 bool, (void),
 default_decimal_float_supported_p)

/* True if the target supports fixed-point.  */
DEFHOOK
(fixed_point_supported_p,
 "",
 bool, (void),
 default_fixed_point_supported_p)

/* Return true if anonymous bitfields affect structure alignment.  */
DEFHOOK
(align_anon_bitfield,
 "",
 bool, (void),
 hook_bool_void_false)

/* Return true if volatile bitfields should use the narrowest type possible.
   Return false if they should use the container type.  */
DEFHOOK
(narrow_volatile_bitfield,
 "",
 bool, (void),
 hook_bool_void_false)

/* Set up target-specific built-in functions.  */
DEFHOOK
(init_builtins,
 "",
 void, (void),
 hook_void_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.  */
DEFHOOK
(builtin_decl,
 "",
 tree, (unsigned code, bool initialize_p), NULL)

/* Expand a target-specific builtin.  */
DEFHOOK
(expand_builtin,
 "",
 rtx,
 (tree exp, rtx target, rtx subtarget, enum machine_mode mode, int ignore),
 default_expand_builtin)

/* 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.  */
DEFHOOK
(resolve_overloaded_builtin,
 "",
 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)

/* Fold a target-specific builtin.  */
DEFHOOK
(fold_builtin,
 "",
 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
 hook_tree_tree_int_treep_bool_null)

/* Returns a code for a target-specific builtin that implements
   reciprocal of the function, or NULL_TREE if not available.  */
DEFHOOK
(builtin_reciprocal,
 "",
 tree, (unsigned fn, bool md_fn, bool sqrt),
 default_builtin_reciprocal)

/* 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.  */
DEFHOOK
(mangle_type,
 "",
 const char *, (const_tree type),
 hook_constcharptr_const_tree_null)

/* Make any adjustments to libfunc names needed for this target.  */
DEFHOOK
(init_libfuncs,
 "",
 void, (void),
 hook_void_void)

 /* Add a __gnu_ prefix to library functions rather than just __.  */
DEFHOOKPOD
(libfunc_gnu_prefix,
 "If false (the default), internal library routines start with two\n\
underscores.  If set to true, these routines start with @code{__gnu_}\n\
instead.  E.g., @code{__muldi3} changes to @code{__gnu_muldi3}.  This\n\
currently only affects functions defined in @file{libgcc2.c}.  If this\n\
is set to true, the @file{tm.h} file must also\n\
@code{#define LIBGCC2_GNU_PREFIX}.",
  bool, false)

/* 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.  */
DEFHOOK
(section_type_flags,
 "",
 unsigned int, (tree decl, const char *name, int reloc),
 default_section_type_flags)

/* True if new jumps cannot be created, to replace existing ones or
   not, at the current point in the compilation.  */
DEFHOOK
(cannot_modify_jumps_p,
 "",
 bool, (void),
 hook_bool_void_false)

/* Return a register class for which branch target register
   optimizations should be applied.  */
DEFHOOK
(branch_target_register_class,
 "",
 reg_class_t, (void),
 default_branch_target_register_class)

/* 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.  */
DEFHOOK
(branch_target_register_callee_saved,
 "",
 bool, (bool after_prologue_epilogue_gen),
 hook_bool_bool_false)

/* Return true if the target supports conditional execution.  */
DEFHOOK
(have_conditional_execution,
 "",
 bool, (void),
 default_have_conditional_execution)

/* Return a new value for loop unroll size.  */
DEFHOOK
(loop_unroll_adjust,
 "",
 unsigned, (unsigned nunroll, struct loop *loop),
 NULL)

/* True if X is a legitimate MODE-mode immediate operand.  */
DEFHOOK
(legitimate_constant_p,
 "",
 bool, (enum machine_mode mode, rtx x),
 hook_bool_mode_rtx_true)

/* True if the constant X cannot be placed in the constant pool.  */
DEFHOOK
(cannot_force_const_mem,
 "",
 bool, (enum machine_mode mode, rtx x),
 hook_bool_mode_rtx_false)

DEFHOOK_UNDOC
(cannot_copy_insn_p,
 "True if the insn @var{x} cannot be duplicated.",
 bool, (rtx), NULL)

/* True if X is considered to be commutative.  */
DEFHOOK
(commutative_p,
 "",
 bool, (const_rtx x, int outer_code),
 hook_bool_const_rtx_commutative_p)

/* True if ADDR is an address-expression whose effect depends
   on the mode of the memory reference it is used in.  */
DEFHOOK
(mode_dependent_address_p,
 "",
 bool, (const_rtx addr),
 default_mode_dependent_address_p)

/* 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.  */
DEFHOOK
(legitimize_address,
 "",
 rtx, (rtx x, rtx oldx, enum machine_mode mode),
 default_legitimize_address)

/* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS.  */
DEFHOOK
(delegitimize_address,
 "",
 rtx, (rtx x),
 delegitimize_mem_from_attrs)

/* Given an RTX, return true if it is not ok to emit it into debug info
   section.  */
DEFHOOK
(const_not_ok_for_debug_p,
 "",
 bool, (rtx x),
 hook_bool_rtx_false)

/* Given an address RTX, say whether it is valid.  */
DEFHOOK
(legitimate_address_p,
 "",
 bool, (enum machine_mode mode, rtx x, bool strict),
 default_legitimate_address_p)

/* True if the given constant can be put into an object_block.  */
DEFHOOK
(use_blocks_for_constant_p,
 "",
 bool, (enum machine_mode mode, const_rtx x),
 hook_bool_mode_const_rtx_false)

/* The minimum and maximum byte offsets for anchored addresses.  */
DEFHOOKPOD
(min_anchor_offset,
 "",
 HOST_WIDE_INT, 0)

DEFHOOKPOD
(max_anchor_offset,
 "",
 HOST_WIDE_INT, 0)

/* True if section anchors can be used to access the given symbol.  */
DEFHOOK
(use_anchors_for_symbol_p,
 "",
 bool, (const_rtx x),
 default_use_anchors_for_symbol_p)

/* 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.  */
DEFHOOK
(function_ok_for_sibcall,
 "",
 bool, (tree decl, tree exp),
 hook_bool_tree_tree_false)

/* 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.  */
DEFHOOK
(set_current_function,
 "",
 void, (tree decl), hook_void_tree)

/* True if EXP should be placed in a "small data" section.  */
DEFHOOK
(in_small_data_p,
 "",
 bool, (const_tree exp),
 hook_bool_const_tree_false)

/* True if EXP names an object for which name resolution must resolve
   to the current executable or shared library.  */
DEFHOOK
(binds_local_p,
 "",
 bool, (const_tree exp),
 default_binds_local_p)

/* Check if profiling code is before or after prologue.  */
DEFHOOK
(profile_before_prologue,
 "It returns true if target wants profile code emitted before prologue.\n\n\
The default version of this hook use the target macro\n\
@code{PROFILE_BEFORE_PROLOGUE}.",
 bool, (void),
 default_profile_before_prologue)

/* 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. */
DEFHOOK
(mangle_decl_assembler_name,
 "",
 tree, (tree decl, tree  id),
 default_mangle_decl_assembler_name)

/* Do something target-specific to record properties of the DECL into
   the associated SYMBOL_REF.  */
DEFHOOK
(encode_section_info,
 "",
 void, (tree decl, rtx rtl, int new_decl_p),
 default_encode_section_info)

/* Undo the effects of encode_section_info on the symbol string.  */
DEFHOOK
(strip_name_encoding,
 "",
 const char *, (const char *name),
 default_strip_name_encoding)

/* If shift optabs for MODE are known to always truncate the shift count,
   return the mask that they apply.  Return 0 otherwise.  */
DEFHOOK
(shift_truncation_mask,
 "",
 unsigned HOST_WIDE_INT, (enum machine_mode mode),
 default_shift_truncation_mask)

/* 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.  */
DEFHOOK
(min_divisions_for_recip_mul,
 "",
 unsigned int, (enum machine_mode mode),
 default_min_divisions_for_recip_mul)

/* 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.  */
DEFHOOK
(mode_rep_extended,
 "",
 int, (enum machine_mode mode, enum machine_mode rep_mode),
 default_mode_rep_extended)

/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))).  */
DEFHOOK
(valid_pointer_mode,
 "",
 bool, (enum machine_mode mode),
 default_valid_pointer_mode)

/* Disambiguate with errno.  */
DEFHOOK
(ref_may_alias_errno,
 "Define this to return nonzero if the memory reference @var{ref}\
  may alias with the system C library errno location.  The default\
  version of this hook assumes the system C library errno location\
  is either a declaration of type int or accessed by dereferencing\
  a pointer to int.",
 bool, (struct ao_ref_s *ref),
 default_ref_may_alias_errno)

/* Support for named address spaces.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_ADDR_SPACE_"
HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)

/* MODE to use for a pointer into another address space.  */
DEFHOOK
(pointer_mode,
 "",
 enum machine_mode, (addr_space_t address_space),
 default_addr_space_pointer_mode)

/* MODE to use for an address in another address space.  */
DEFHOOK
(address_mode,
 "",
 enum machine_mode, (addr_space_t address_space),
 default_addr_space_address_mode)

/* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
   in another address space.  */
DEFHOOK
(valid_pointer_mode,
 "",
 bool, (enum machine_mode mode, addr_space_t as),
 default_addr_space_valid_pointer_mode)

/* True if an address is a valid memory address to a given named address
   space for a given mode.  */
DEFHOOK
(legitimate_address_p,
 "",
 bool, (enum machine_mode mode, rtx exp, bool strict, addr_space_t as),
 default_addr_space_legitimate_address_p)

/* Return an updated address to convert an invalid pointer to a named
   address space to a valid one.  If NULL_RTX is returned use machine
   independent methods to make the address valid.  */
DEFHOOK
(legitimize_address,
 "",
 rtx, (rtx x, rtx oldx, enum machine_mode mode, addr_space_t as),
 default_addr_space_legitimize_address)

/* True if one named address space is a subset of another named address. */
DEFHOOK
(subset_p,
 "",
 bool, (addr_space_t subset, addr_space_t superset),
 default_addr_space_subset_p)

/* Function to convert an rtl expression from one address space to another.  */
DEFHOOK
(convert,
 "",
 rtx, (rtx op, tree from_type, tree to_type),
 default_addr_space_convert)

HOOK_VECTOR_END (addr_space)

#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_"

/* True if MODE is valid for the target.  By "valid", we mean able to
   be manipulated in non-trivial ways.  In particular, this means all
   the arithmetic is supported.  */
DEFHOOK
(scalar_mode_supported_p,
 "",
 bool, (enum machine_mode mode),
 default_scalar_mode_supported_p)

/* Similarly for vector modes.  "Supported" here is less strict.  At
   least some operations are supported; need to check optabs or builtins
   for further details.  */
DEFHOOK
(vector_mode_supported_p,
 "",
 bool, (enum machine_mode mode),
 hook_bool_mode_false)

/* True if we should try to use a scalar mode to represent an array,
   overriding the usual MAX_FIXED_MODE limit.  */
DEFHOOK
(array_mode_supported_p,
 "Return true if GCC should try to use a scalar mode to store an array\n\
of @var{nelems} elements, given that each element has mode @var{mode}.\n\
Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
and allows GCC to use any defined integer mode.\n\
\n\
One use of this hook is to support vector load and store operations\n\
that operate on several homogeneous vectors.  For example, ARM NEON\n\
has operations like:\n\
\n\
@smallexample\n\
int8x8x3_t vld3_s8 (const int8_t *)\n\
@end smallexample\n\
\n\
where the return type is defined as:\n\
\n\
@smallexample\n\
typedef struct int8x8x3_t\n\
@{\n\
  int8x8_t val[3];\n\
@} int8x8x3_t;\n\
@end smallexample\n\
\n\
If this hook allows @code{val} to have a scalar mode, then\n\
@code{int8x8x3_t} can have the same mode.  GCC can then store\n\
@code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
 bool, (enum machine_mode mode, unsigned HOST_WIDE_INT nelems),
 hook_bool_mode_uhwi_false)

/* Compute cost of moving data from a register of class FROM to one of
   TO, using MODE.  */
DEFHOOK
(register_move_cost,
 "",
 int, (enum machine_mode mode, reg_class_t from, reg_class_t to),
 default_register_move_cost)

/* Compute cost of moving registers to/from memory.  */
/* ??? Documenting the argument types for this hook requires a GFDL
   license grant.  Also, the documentation uses a different name for RCLASS.  */
DEFHOOK
(memory_move_cost,
 "",
 int, (enum machine_mode mode, reg_class_t rclass, bool in),
 default_memory_move_cost)

/* True for MODE if the target expects that registers in this mode will
   be allocated to registers in a small register class.  The compiler is
   allowed to use registers explicitly used in the rtl as spill registers
   but it should prevent extending the lifetime of these registers.  */
DEFHOOK
(small_register_classes_for_mode_p,
 "",
 bool, (enum machine_mode mode),
 hook_bool_mode_false)

/* Register number for a flags register.  Only needs to be defined if the
   target is constrainted to use post-reload comparison elimination.  */
DEFHOOKPOD
(flags_regnum,
 "If the target has a dedicated flags register, and it needs to use the\
 post-reload comparison elimination pass, then this value should be set\
 appropriately.",
 unsigned int, INVALID_REGNUM)

/* Compute a (partial) cost for rtx X.  Return true if the complete
   cost has been computed, and false if subexpressions should be
   scanned.  In either case, *TOTAL contains the cost result.  */
/* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
   not necessarily defined at this point.  */
DEFHOOK
(rtx_costs,
 "",
 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
 hook_bool_rtx_int_int_int_intp_bool_false)

/* Compute the cost of X, used as an address.  Never called with
   invalid addresses.  */
DEFHOOK
(address_cost,
 "",
 int, (rtx address, bool speed),
 default_address_cost)

/* Return where to allocate pseudo for a given hard register initial value.  */
DEFHOOK
(allocate_initial_value,
 "",
 rtx, (rtx hard_reg), NULL)

/* Return nonzero if evaluating UNSPEC[_VOLATILE] X might cause a trap.
   FLAGS has the same meaning as in rtlanal.c: may_trap_p_1.  */
DEFHOOK
(unspec_may_trap_p,
 "",
 int, (const_rtx x, unsigned flags),
 default_unspec_may_trap_p)

/* Given a register, this hook should return a parallel of registers
   to represent where to find the register pieces.  Define this hook
   if the register and its mode are represented in Dwarf in
   non-contiguous locations, or if the register should be
   represented in more than one register in Dwarf.  Otherwise, this
   hook should return NULL_RTX.  */
DEFHOOK
(dwarf_register_span,
 "",
 rtx, (rtx reg),
 hook_rtx_rtx_null)

/* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
   entries not corresponding directly to registers below
   FIRST_PSEUDO_REGISTER, this hook should generate the necessary
   code, given the address of the table.  */
DEFHOOK
(init_dwarf_reg_sizes_extra,
 "",
 void, (tree address),
 hook_void_tree)

/* Fetch the fixed register(s) which hold condition codes, for
   targets where it makes sense to look for duplicate assignments to
   the condition codes.  This should return true if there is such a
   register, false otherwise.  The arguments should be set to the
   fixed register numbers.  Up to two condition code registers are
   supported.  If there is only one for this target, the int pointed
   at by the second argument should be set to -1.  */
DEFHOOK
(fixed_condition_code_regs,
 "",
 bool, (unsigned int *p1, unsigned int *p2),
 hook_bool_uintp_uintp_false)

/* If two condition code modes are compatible, return a condition
     code mode which is compatible with both, such that a comparison
     done in the returned mode will work for both of the original
     modes.  If the condition code modes are not compatible, return
     VOIDmode.  */
DEFHOOK
(cc_modes_compatible,
 "",
 enum machine_mode, (enum machine_mode m1, enum machine_mode m2),
 default_cc_modes_compatible)

/* Do machine-dependent code transformations.  Called just before
     delayed-branch scheduling.  */
DEFHOOK
(machine_dependent_reorg,
 "",
 void, (void), NULL)

/* Create the __builtin_va_list type.  */
DEFHOOK
(build_builtin_va_list,
 "",
 tree, (void),
 std_build_builtin_va_list)

/* Enumerate the va list variants.  */
DEFHOOK
(enum_va_list_p,
 "",
 int, (int idx, const char **pname, tree *ptree),
 NULL)

/* Get the cfun/fndecl calling abi __builtin_va_list type.  */
DEFHOOK
(fn_abi_va_list,
 "",
 tree, (tree fndecl),
 std_fn_abi_va_list)

/* Get the __builtin_va_list type dependent on input type.  */
DEFHOOK
(canonical_va_list_type,
 "",
 tree, (tree type),
 std_canonical_va_list_type)

/* ??? Documenting this hook requires a GFDL license grant.  */
DEFHOOK_UNDOC
(expand_builtin_va_start,
"Expand the @code{__builtin_va_start} builtin.",
 void, (tree valist, rtx nextarg), NULL)

/* Gimplifies a VA_ARG_EXPR.  */
DEFHOOK
(gimplify_va_arg_expr,
 "",
 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
 std_gimplify_va_arg_expr)

/* Validity-checking routines for PCH files, target-specific.
   get_pch_validity returns a pointer to the data to be stored,
   and stores the size in its argument.  pch_valid_p gets the same
   information back and returns NULL if the PCH is valid,
   or an error message if not.  */
DEFHOOK
(get_pch_validity,
 "",
 void *, (size_t *sz),
 default_get_pch_validity)

DEFHOOK
(pch_valid_p,
 "",
 const char *, (const void *data, size_t sz),
 default_pch_valid_p)

DEFHOOK
(prepare_pch_save,
 "Called before writing out a PCH file.  If the target has some\n\
garbage-collected data that needs to be in a particular state on PCH loads,\n\
it can use this hook to enforce that state.  Very few targets need\n\
to do anything here.",
 void, (void),
 hook_void_void)

/* 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.  */
DEFHOOK
(check_pch_target_flags,
 "",
 const char *, (int pch_flags), NULL)

/* 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.  */
DEFHOOK
(default_short_enums,
 "",
 bool, (void),
 hook_bool_void_false)

/* This target hook returns an rtx that is used to store the address
   of the current frame into the built-in setjmp buffer.  */
DEFHOOK
(builtin_setjmp_frame_value,
 "",
 rtx, (void),
 default_builtin_setjmp_frame_value)

/* This target hook should add STRING_CST trees for any hard regs
   the port wishes to automatically clobber for an asm.  */
DEFHOOK
(md_asm_clobbers,
 "",
 tree, (tree outputs, tree inputs, tree clobbers),
 hook_tree_tree_tree_tree_3rd_identity)

/* 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.  */
DEFHOOK
(dwarf_calling_convention,
 "",
 int, (const_tree function),
 hook_int_const_tree_0)

/* 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.  */
DEFHOOK
(dwarf_handle_frame_unspec,
 "",
 void, (const char *label, rtx pattern, int index), NULL)

/* ??? Documenting this hook requires a GFDL license grant.  */
DEFHOOK_UNDOC
(stdarg_optimize_hook,
"Perform architecture specific checking of statements gimplified\
 from @code{VA_ARG_EXPR}.  @var{stmt} is the statement.  Returns true if\
 the statement doesn't need to be checked for @code{va_list} references.",
 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)

/* 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.  */
DEFHOOK
(stack_protect_guard,
 "",
 tree, (void),
 default_stack_protect_guard)

/* This target hook allows the operating system to override the CALL_EXPR
   that is invoked when a check vs the guard variable fails.  */
DEFHOOK
(stack_protect_fail,
 "",
 tree, (void),
 default_external_stack_protect_fail)

/* Returns NULL if target supports the insn within a doloop block,
   otherwise it returns an error message.  */
DEFHOOK
(invalid_within_doloop,
 "",
 const char *, (const_rtx insn),
 default_invalid_within_doloop)

DEFHOOK
(valid_dllimport_attribute_p,
"@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
 specified.  Use this hook if the target needs to add extra validation\
 checks to @code{handle_dll_attribute}.",
 bool, (const_tree decl),
 hook_bool_const_tree_true)

/* If non-zero, align constant anchors in CSE to a multiple of this
   value.  */
DEFHOOKPOD
(const_anchor,
 "",
 unsigned HOST_WIDE_INT, 0)

/* Defines, which target-dependent bits (upper 16) are used by port  */
DEFHOOK
(memmodel_check,
 "",
 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)

/* Functions relating to calls - argument passing, returns, etc.  */
/* Members of struct call have no special macro prefix.  */
HOOK_VECTOR (TARGET_CALLS, calls)

DEFHOOK
(promote_function_mode,
 "",
 enum machine_mode, (const_tree type, enum machine_mode mode, int *punsignedp,
                     const_tree funtype, int for_return),
 default_promote_function_mode)

DEFHOOK
(promote_prototypes,
 "",
 bool, (const_tree fntype),
 hook_bool_const_tree_false)

DEFHOOK
(struct_value_rtx,
 "",
 rtx, (tree fndecl, int incoming),
 hook_rtx_tree_int_null)
DEFHOOK
(return_in_memory,
 "",
 bool, (const_tree type, const_tree fntype),
 default_return_in_memory)

DEFHOOK
(return_in_msb,
 "",
 bool, (const_tree type),
 hook_bool_const_tree_false)

/* 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.  */
DEFHOOK
(pass_by_reference,
 "",
 bool,
 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)

DEFHOOK
(expand_builtin_saveregs,
 "",
 rtx, (void),
 default_expand_builtin_saveregs)

/* Returns pretend_argument_size.  */
DEFHOOK
(setup_incoming_varargs,
 "",
 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
        int *pretend_args_size, int second_time),
 default_setup_incoming_varargs)

DEFHOOK
(strict_argument_naming,
 "",
 bool, (cumulative_args_t ca),
 hook_bool_CUMULATIVE_ARGS_false)

/* Returns true if we should use
   targetm.calls.setup_incoming_varargs() and/or
   targetm.calls.strict_argument_naming().  */
DEFHOOK
(pretend_outgoing_varargs_named,
 "",
 bool, (cumulative_args_t ca),
 default_pretend_outgoing_varargs_named)

/* Given a complex type T, return true if a parameter of type T
   should be passed as two scalars.  */
DEFHOOK
(split_complex_arg,
 "",
 bool, (const_tree type), NULL)

/* 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.  */
DEFHOOK
(must_pass_in_stack,
 "",
 bool, (enum machine_mode mode, const_tree type),
 must_pass_in_stack_var_size_or_pad)

/* 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.  */
DEFHOOK
(callee_copies,
 "",
 bool,
 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)

/* 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.  */
DEFHOOK
(arg_partial_bytes,
 "",
 int, (cumulative_args_t cum, enum machine_mode mode, tree type, bool named),
 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)

/* Update the state in CA to advance past an argument in the
   argument list.  The values MODE, TYPE, and NAMED describe that
   argument.  */
DEFHOOK
(function_arg_advance,
 "",
 void,
 (cumulative_args_t ca, enum machine_mode mode, const_tree type, bool named),
 default_function_arg_advance)

/* Return zero if the argument described by the state of CA should
   be placed on a stack, or a hard register in which to store the
   argument.  The values MODE, TYPE, and NAMED describe that
   argument.  */
DEFHOOK
(function_arg,
 "",
 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
       bool named),
 default_function_arg)

/* Likewise, but for machines with register windows.  Return the
   location where the argument will appear to the callee.  */
DEFHOOK
(function_incoming_arg,
 "",
 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
       bool named),
 default_function_incoming_arg)

DEFHOOK
(function_arg_boundary,
 "",
 unsigned int, (enum machine_mode mode, const_tree type),
 default_function_arg_boundary)

DEFHOOK
(function_arg_round_boundary,
 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
which is the default value for this hook.  You can define this hook to\n\
return a different value if an argument size must be rounded to a larger\n\
value.",
 unsigned int, (enum machine_mode mode, const_tree type),
 default_function_arg_round_boundary)

/* Return the diagnostic message string if function without a prototype
   is not allowed for this 'val' argument; NULL otherwise. */
DEFHOOK
(invalid_arg_for_unprototyped_fn,
 "",
 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
 hook_invalid_arg_for_unprototyped_fn)

/* Return an rtx for the return value location of the function
   specified by FN_DECL_OR_TYPE with a return type of RET_TYPE.  */
DEFHOOK
(function_value,
 "",
 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
 default_function_value)

/* Return the rtx for the result of a libcall of mode MODE,
   calling the function FN_NAME.  */
DEFHOOK
(libcall_value,
 "",
 rtx, (enum machine_mode mode, const_rtx fun),
 default_libcall_value)

/* Return true if REGNO is a possible register number for
   a function value as seen by the caller.  */
DEFHOOK
(function_value_regno_p,
 "",
 bool, (const unsigned int regno),
 default_function_value_regno_p)

/* ??? Documenting this hook requires a GFDL license grant.  */
DEFHOOK_UNDOC
(internal_arg_pointer,
"Return an rtx for the argument pointer incoming to the\
 current function.",
 rtx, (void),
 default_internal_arg_pointer)

/* Update the current function stack boundary if needed.  */
DEFHOOK
(update_stack_boundary,
 "",
 void, (void), NULL)

/* Handle stack alignment and return an rtx for Dynamic Realign
   Argument Pointer if necessary.  */
DEFHOOK
(get_drap_rtx,
 "",
 rtx, (void), NULL)

/* Return true if all function parameters should be spilled to the
   stack.  */
DEFHOOK
(allocate_stack_slots_for_args,
 "",
 bool, (void),
 hook_bool_void_true)

/* Return an rtx for the static chain for FNDECL.  If INCOMING_P is true,
       then it should be for the callee; otherwise for the caller.  */
DEFHOOK
(static_chain,
 "",
 rtx, (const_tree fndecl, bool incoming_p),
 default_static_chain)

/* Fill in the trampoline at MEM with a call to FNDECL and a
   static chain value of CHAIN.  */
DEFHOOK
(trampoline_init,
 "",
 void, (rtx m_tramp, tree fndecl, rtx static_chain),
 default_trampoline_init)

/* Adjust the address of the trampoline in a target-specific way.  */
DEFHOOK
(trampoline_adjust_address,
 "",
 rtx, (rtx addr), NULL)

/* Return the number of bytes of its own arguments that a function
   pops on returning, or 0 if the function pops no arguments and the
   caller must therefore pop them all after the function returns.  */
/* ??? tm.texi has no types for the parameters.  */
DEFHOOK
(return_pops_args,
 "",
 int, (tree fundecl, tree funtype, int size),
 default_return_pops_args)

/* Return a mode wide enough to copy any function value that might be
   returned.  */
DEFHOOK
(get_raw_result_mode,
 "This target hook returns the mode to be used when accessing raw return\
 registers in @code{__builtin_return}.  Define this macro if the value\
 in @var{reg_raw_mode} is not correct.",
 enum machine_mode, (int regno),
 default_get_reg_raw_mode)

/* Return a mode wide enough to copy any argument value that might be
   passed.  */
DEFHOOK
(get_raw_arg_mode,
 "This target hook returns the mode to be used when accessing raw argument\
 registers in @code{__builtin_apply_args}.  Define this macro if the value\
 in @var{reg_raw_mode} is not correct.",
 enum machine_mode, (int regno),
 default_get_reg_raw_mode)

HOOK_VECTOR_END (calls)

/* Return the diagnostic message string if conversion from FROMTYPE
   to TOTYPE is not allowed, NULL otherwise.  */
DEFHOOK
(invalid_conversion,
 "",
 const char *, (const_tree fromtype, const_tree totype),
 hook_constcharptr_const_tree_const_tree_null)

/* Return the diagnostic message string if the unary operation OP is
   not permitted on TYPE, NULL otherwise.  */
DEFHOOK
(invalid_unary_op,
 "",
 const char *, (int op, const_tree type),
 hook_constcharptr_int_const_tree_null)

/* Return the diagnostic message string if the binary operation OP
   is not permitted on TYPE1 and TYPE2, NULL otherwise.  */
DEFHOOK
(invalid_binary_op,
 "",
 const char *, (int op, const_tree type1, const_tree type2),
 hook_constcharptr_int_const_tree_const_tree_null)

/* Return the diagnostic message string if TYPE is not valid as a
   function parameter type, NULL otherwise.  */
DEFHOOK
(invalid_parameter_type,
 "",
 const char *, (const_tree type),
 hook_constcharptr_const_tree_null)

/* Return the diagnostic message string if TYPE is not valid as a
   function return type, NULL otherwise.  */
DEFHOOK
(invalid_return_type,
 "",
 const char *, (const_tree type),
 hook_constcharptr_const_tree_null)

/* If values of TYPE are promoted to some other type when used in
   expressions (analogous to the integer promotions), return that type,
   or NULL_TREE otherwise.  */
DEFHOOK
(promoted_type,
 "",
 tree, (const_tree type),
 hook_tree_const_tree_null)

/* Convert EXPR to TYPE, if target-specific types with special conversion
   rules are involved.  Return the converted expression, or NULL to apply
   the standard conversion rules.  */
DEFHOOK
(convert_to_type,
 "",
 tree, (tree type, tree expr),
 hook_tree_tree_tree_null)

/* Return the class for a secondary reload, and fill in extra information.  */
DEFHOOK
(secondary_reload,
 "",
 reg_class_t,
 (bool in_p, rtx x, reg_class_t reload_class, enum machine_mode reload_mode,
  secondary_reload_info *sri),
 default_secondary_reload)

/* Given an rtx X being reloaded into a reg required to be in class CLASS,
   return the class of reg to actually use.  */
DEFHOOK
(preferred_reload_class,
 "",
 reg_class_t,
 (rtx x, reg_class_t rclass),
 default_preferred_reload_class)

/* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
   input reloads.  */
DEFHOOK
(preferred_output_reload_class,
 "",
 reg_class_t,
 (rtx x, reg_class_t rclass),
 default_preferred_output_reload_class)

DEFHOOK
(class_likely_spilled_p,
 "",
 bool, (reg_class_t rclass),
 default_class_likely_spilled_p)

/* Return the maximum number of consecutive registers
   needed to represent mode MODE in a register of class RCLASS.  */
DEFHOOK
(class_max_nregs,
 "",
 unsigned char, (reg_class_t rclass, enum machine_mode mode),
 default_class_max_nregs)

DEFHOOK
(preferred_rename_class,
 "A target hook that places additional preference on the register\
 class to use when it is necessary to rename a register in class\
 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
 preferred register class is found or hook @code{preferred_rename_class}\
 is not implemented.\
 Sometimes returning a more restrictive class makes better code.  For\
 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
 smaller than instructions using @code{GENERIC_REGS}.  By returning\
 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
 be reduced.",
 reg_class_t, (reg_class_t rclass),
 default_preferred_rename_class)

/* This target hook allows the backend to perform additional
   processing while initializing for variable expansion.  */
DEFHOOK
(expand_to_rtl_hook,
 "",
 void, (void),
 hook_void_void)

/* This target hook allows the backend to perform additional
   instantiations on rtx that are not actually in insns yet,
   but will be later.  */
DEFHOOK
(instantiate_decls,
 "",
 void, (void),
 hook_void_void)

/* Return true if is OK to use a hard register REGNO as scratch register
   in peephole2.  */
DEFHOOK
(hard_regno_scratch_ok,
 "",
 bool, (unsigned int regno),
 default_hard_regno_scratch_ok)

/* Return the smallest number of different values for which it is best to
   use a jump-table instead of a tree of conditional branches.  */
DEFHOOK
(case_values_threshold,
 "",
 unsigned int, (void),
 default_case_values_threshold)

/* Retutn true if a function must have and use a frame pointer.  */
DEFHOOK
(frame_pointer_required,
 "",
 bool, (void),
 hook_bool_void_false)

/* Returns true if the compiler is allowed to try to replace register number
   from-reg with register number to-reg.  */
DEFHOOK
(can_eliminate,
 "",
 bool, (const int from_reg, const int to_reg),
 hook_bool_const_int_const_int_true)

/* Modify any or all of fixed_regs, call_used_regs, global_regs,
   reg_names, and reg_class_contents to account of the vagaries of the
   target.  */
DEFHOOK
(conditional_register_usage,
 "",
 void, (void),
 hook_void_void)

/* Functions specific to the C family of frontends.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_C_"
HOOK_VECTOR (TARGET_C, c)

/* ??? Documenting this hook requires a GFDL license grant.  */
DEFHOOK_UNDOC
(mode_for_suffix,
"Return machine mode for non-standard constant literal suffix @var{c},\
 or VOIDmode if non-standard suffixes are unsupported.",
 enum machine_mode, (char c),
 default_mode_for_suffix)

HOOK_VECTOR_END (c)

/* Functions specific to the C++ frontend.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_CXX_"
HOOK_VECTOR (TARGET_CXX, cxx)

/* Return the integer type used for guard variables.  */
DEFHOOK
(guard_type,
 "",
 tree, (void),
 default_cxx_guard_type)

/* Return true if only the low bit of the guard should be tested.  */
DEFHOOK
(guard_mask_bit,
 "",
 bool, (void),
 hook_bool_void_false)

/* Returns the size of the array cookie for an array of type.  */
DEFHOOK
(get_cookie_size,
 "",
 tree, (tree type),
 default_cxx_get_cookie_size)

/* Returns true if the element size should be stored in the array cookie.  */
DEFHOOK
(cookie_has_size,
 "",
 bool, (void),
 hook_bool_void_false)

/* Allows backends to perform additional processing when
   deciding if a class should be exported or imported.  */
DEFHOOK
(import_export_class,
 "",
 int, (tree type, int import_export), NULL)

/* Returns true if constructors and destructors return "this".  */
DEFHOOK
(cdtor_returns_this,
 "",
 bool, (void),
 hook_bool_void_false)

/* 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.  */
DEFHOOK
(key_method_may_be_inline,
 "",
 bool, (void),
 hook_bool_void_true)

DEFHOOK
(determine_class_data_visibility,
"@var{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\
 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
 void, (tree decl),
 hook_void_tree)

/* 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.  */
DEFHOOK
(class_data_always_comdat,
 "",
 bool, (void),
 hook_bool_void_true)

/* Returns true (the default) if the RTTI for the basic types,
   which is always defined in the C++ runtime, should be COMDAT;
   false if it should not be COMDAT.  */
DEFHOOK
(library_rtti_comdat,
 "",
 bool, (void),
 hook_bool_void_true)

/* Returns true if __aeabi_atexit should be used to register static
   destructors.  */
DEFHOOK
(use_aeabi_atexit,
 "",
 bool, (void),
 hook_bool_void_false)

/* Returns true if target may use atexit in the same manner as
   __cxa_atexit  to register static destructors.  */
DEFHOOK
(use_atexit_for_cxa_atexit,
 "",
 bool, (void),
 hook_bool_void_false)

DEFHOOK
(adjust_class_at_definition,
"@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\
 visibility or perform any other required target modifications).",
 void, (tree type),
 hook_void_tree)

DEFHOOK
(decl_mangling_context,
 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
 tree, (const_tree decl),
 hook_tree_const_tree_null)

HOOK_VECTOR_END (cxx)

/* Functions and data for emulated TLS support.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_EMUTLS_"
HOOK_VECTOR (TARGET_EMUTLS, emutls)

/* Name of the address and common functions.  */
DEFHOOKPOD
(get_address,
 "",
 const char *, "__builtin___emutls_get_address")

DEFHOOKPOD
(register_common,
 "",
 const char *, "__builtin___emutls_register_common")

/* Prefixes for proxy variable and template.  */
DEFHOOKPOD
(var_section,
 "",
 const char *, NULL)

DEFHOOKPOD
(tmpl_section,
 "",
 const char *, NULL)

/* Prefixes for proxy variable and template.  */
DEFHOOKPOD
(var_prefix,
 "",
 const char *, NULL)

DEFHOOKPOD
(tmpl_prefix,
 "",
 const char *, NULL)

/* Function to generate field definitions of the proxy variable.  */
DEFHOOK
(var_fields,
 "",
 tree, (tree type, tree *name),
 default_emutls_var_fields)

/* Function to initialize a proxy variable.  */
DEFHOOK
(var_init,
 "",
 tree, (tree var, tree decl, tree tmpl_addr),
 default_emutls_var_init)

/* Whether we are allowed to alter the usual alignment of the
   proxy variable.  */
DEFHOOKPOD
(var_align_fixed,
 "",
 bool, false)

/* Whether we can emit debug information for TLS vars.  */
DEFHOOKPOD
(debug_form_tls_address,
 "",
 bool, false)

HOOK_VECTOR_END (emutls)

#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_OPTION_"
HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)

/* Function to validate the attribute((option(...))) strings or NULL.  If
   the option is validated, it is assumed that DECL_FUNCTION_SPECIFIC will
   be filled in in the function decl node.  */
DEFHOOK
(valid_attribute_p,
 "",
 bool, (tree fndecl, tree name, tree args, int flags),
 default_target_option_valid_attribute_p)

/* Function to save any extra target state in the target options structure.  */
DEFHOOK
(save,
 "",
 void, (struct cl_target_option *ptr), NULL)

/* Function to restore any extra target state from the target options
   structure.  */
DEFHOOK
(restore,
 "",
 void, (struct cl_target_option *ptr), NULL)

/* Function to print any extra target state from the target options
   structure.  */
DEFHOOK
(print,
 "",
 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)

/* Function to parse arguments to be validated for #pragma option, and to
   change the state if the options are valid.  If the first argument is
   NULL, the second argument specifies the default options to use.  Return
   true if the options are valid, and set the current state.  */
/* ??? The documentation in tm.texi is incomplete.  */
DEFHOOK
(pragma_parse,
 "",
 bool, (tree args, tree pop_target),
 default_target_option_pragma_parse)

/* Do option overrides for the target.  */
DEFHOOK
(override,
 "",
 void, (void),
 hook_void_void)

/* Function to determine if one function can inline another function.  */
#undef HOOK_PREFIX
#define HOOK_PREFIX "TARGET_"
DEFHOOK
(can_inline_p,
 "",
 bool, (tree caller, tree callee),
 default_target_can_inline_p)

HOOK_VECTOR_END (target_option)

/* 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. */
DEFHOOK
(extra_live_on_entry,
 "",
 void, (bitmap regs),
 hook_void_bitmap)

/* Fill in additional registers set up by prologue into a regset.  */
DEFHOOK
(set_up_by_prologue,
 "This hook should add additional registers that are computed by the prologue\
 to the hard regset for shrink-wrapping optimization purposes.",
 void, (struct hard_reg_set_container *),
 NULL)

/* Determine the type of unwind info to emit for debugging.  */
DEFHOOK
(debug_unwind_info,
 "",
 enum unwind_info_type, (void),
 default_debug_unwind_info)

DEFHOOKPOD
(atomic_test_and_set_trueval,
 "This value should be set if the result written by\
 @code{atomic_test_and_set} is not exactly 1, i.e. the\
 @code{bool} @code{true}.",
 unsigned char, 1)
 
/* Leave the boolean fields at the end.  */

/* True if we can create zeroed data by switching to a BSS section
   and then using ASM_OUTPUT_SKIP to allocate the space.  */
DEFHOOKPOD
(have_switchable_bss_sections,
 "",
 bool, false)

/* True if "native" constructors and destructors are supported,
   false if we're using collect2 for the job.  */
DEFHOOKPOD
(have_ctors_dtors,
 "",
 bool, false)

/* True if thread-local storage is supported.  */
DEFHOOKPOD
(have_tls,
 "",
 bool, false)

/* True if a small readonly data section is supported.  */
DEFHOOKPOD
(have_srodata_section,
 "",
 bool, false)

/* True if EH frame info sections should be zero-terminated.  */
DEFHOOKPOD
(terminate_dw2_eh_frame_info,
 "",
 bool, true)

/* True if #NO_APP should be emitted at the beginning of assembly output.  */
DEFHOOKPOD
(asm_file_start_app_off,
 "",
 bool, false)

/* True if output_file_directive should be called for main_input_filename
   at the beginning of assembly output.  */
DEFHOOKPOD
(asm_file_start_file_directive,
 "",
 bool, false)

/* True if the target is allowed to reorder memory accesses unless
   synchronization is explicitly requested.  */
DEFHOOKPOD
(relaxed_ordering,
 "",
 bool, false)

/* Returns true if we should generate exception tables for use with the
   ARM EABI.  The effects the encoding of function exception specifications.  */
DEFHOOKPOD
(arm_eabi_unwinder,
 "",
 bool, false)

DEFHOOKPOD
(want_debug_pub_sections,
 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
 should be emitted.  These sections are not used on most platforms, and\
 in particular GDB does not use them.",
 bool, false)

DEFHOOKPOD
(force_at_comp_dir,
 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
 compilation unit.  This attribute is required for the darwin linker \
 to emit debug information.",
 bool, false)

DEFHOOKPOD
(delay_sched2, "True if sched2 is not to be run at its normal place.  \
This usually means it will be run as part of machine-specific reorg.",
bool, false)

DEFHOOKPOD
(delay_vartrack, "True if vartrack is not to be run at its normal place.  \
This usually means it will be run as part of machine-specific reorg.",
bool, false)

/* Leave the boolean fields at the end.  */

/* Close the 'struct gcc_target' definition.  */
HOOK_VECTOR_END (C90_EMPTY_HACK)