466 lines
20 KiB
C++
466 lines
20 KiB
C++
/* Data structure definitions for a generic GCC target.
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Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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In other words, you are welcome to use, share and improve this program.
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You are forbidden to forbid anyone else to use, share and improve
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what you give them. Help stamp out software-hoarding! */
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/* This file contains a data structure that describes a GCC target.
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At present it is incomplete, but in future it should grow to
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contain most or all target machine and target O/S specific
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information.
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This structure has its initializer declared in target-def.h in the
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form of large macro TARGET_INITIALIZER that expands to many smaller
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macros.
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The smaller macros each initialize one component of the structure,
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and each has a default. Each target should have a file that
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includes target.h and target-def.h, and overrides any inappropriate
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defaults by undefining the relevant macro and defining a suitable
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replacement. That file should then contain the definition of
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"targetm" like so:
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struct gcc_target targetm = TARGET_INITIALIZER;
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Doing things this way allows us to bring together everything that
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defines a GCC target. By supplying a default that is appropriate
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to most targets, we can easily add new items without needing to
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edit dozens of target configuration files. It should also allow us
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to gradually reduce the amount of conditional compilation that is
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scattered throughout GCC. */
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#include "tm.h"
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struct gcc_target
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{
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/* Functions that output assembler for the target. */
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struct asm_out
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{
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/* Opening and closing parentheses for asm expression grouping. */
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const char *open_paren, *close_paren;
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/* Assembler instructions for creating various kinds of integer object. */
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const char *byte_op;
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struct asm_int_op
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{
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const char *hi;
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const char *si;
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const char *di;
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const char *ti;
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} aligned_op, unaligned_op;
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/* Try to output the assembler code for an integer object whose
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value is given by X. SIZE is the size of the object in bytes and
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ALIGNED_P indicates whether it is aligned. Return true if
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successful. Only handles cases for which BYTE_OP, ALIGNED_OP
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and UNALIGNED_OP are NULL. */
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bool (* integer) (rtx x, unsigned int size, int aligned_p);
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/* Output code that will globalize a label. */
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void (* globalize_label) (FILE *, const char *);
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/* Output an internal label. */
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void (* internal_label) (FILE *, const char *, unsigned long);
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/* Emit an assembler directive to set visibility for the symbol
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associated with the tree decl. */
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void (* visibility) (tree, int);
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/* Output the assembler code for entry to a function. */
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void (* function_prologue) (FILE *, HOST_WIDE_INT);
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/* Output the assembler code for end of prologue. */
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void (* function_end_prologue) (FILE *);
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/* Output the assembler code for start of epilogue. */
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void (* function_begin_epilogue) (FILE *);
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/* Output the assembler code for function exit. */
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void (* function_epilogue) (FILE *, HOST_WIDE_INT);
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/* Switch to an arbitrary section NAME with attributes as
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specified by FLAGS. */
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void (* named_section) (const char *, unsigned int);
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/* Switch to the section that holds the exception table. */
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void (* exception_section) (void);
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/* Switch to the section that holds the exception frames. */
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void (* eh_frame_section) (void);
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/* Select and switch to a section for EXP. It may be a DECL or a
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constant. RELOC is nonzero if runtime relocations must be applied;
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bit 1 will be set if the runtime relocations require non-local
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name resolution. ALIGN is the required alignment of the data. */
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void (* select_section) (tree, int, unsigned HOST_WIDE_INT);
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/* Select and switch to a section for X with MODE. ALIGN is
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the desired alignment of the data. */
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void (* select_rtx_section) (enum machine_mode, rtx,
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unsigned HOST_WIDE_INT);
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/* Select a unique section name for DECL. RELOC is the same as
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for SELECT_SECTION. */
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void (* unique_section) (tree, int);
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/* Output a constructor for a symbol with a given priority. */
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void (* constructor) (rtx, int);
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/* Output a destructor for a symbol with a given priority. */
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void (* destructor) (rtx, int);
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/* Output the assembler code for a thunk function. THUNK_DECL is the
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declaration for the thunk function itself, FUNCTION is the decl for
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the target function. DELTA is an immediate constant offset to be
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added to THIS. If VCALL_OFFSET is nonzero, the word at
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*(*this + vcall_offset) should be added to THIS. */
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void (* output_mi_thunk) (FILE *file, tree thunk_decl,
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HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
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tree function_decl);
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/* Determine whether output_mi_thunk would succeed. */
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/* ??? Ideally, this hook would not exist, and success or failure
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would be returned from output_mi_thunk directly. But there's
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too much undo-able setup involved in invoking output_mi_thunk.
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Could be fixed by making output_mi_thunk emit rtl instead of
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text to the output file. */
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bool (* can_output_mi_thunk) (tree thunk_decl, HOST_WIDE_INT delta,
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HOST_WIDE_INT vcall_offset,
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tree function_decl);
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/* Output any boilerplate text needed at the beginning of a
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translation unit. */
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void (*file_start) (void);
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/* Output any boilerplate text needed at the end of a
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translation unit. */
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void (*file_end) (void);
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/* Output an assembler pseudo-op to declare a library function name
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external. */
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void (*external_libcall) (rtx);
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} asm_out;
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/* Functions relating to instruction scheduling. */
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struct sched
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{
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/* Given the current cost, COST, of an insn, INSN, calculate and
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return a new cost based on its relationship to DEP_INSN through
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the dependence LINK. The default is to make no adjustment. */
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int (* adjust_cost) (rtx insn, rtx link, rtx def_insn, int cost);
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/* Adjust the priority of an insn as you see fit. Returns the new
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priority. */
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int (* adjust_priority) (rtx, int);
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/* Function which returns the maximum number of insns that can be
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scheduled in the same machine cycle. This must be constant
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over an entire compilation. The default is 1. */
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int (* issue_rate) (void);
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/* Calculate how much this insn affects how many more insns we
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can emit this cycle. Default is they all cost the same. */
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int (* variable_issue) (FILE *, int, rtx, int);
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/* Initialize machine-dependent scheduling code. */
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void (* md_init) (FILE *, int, int);
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/* Finalize machine-dependent scheduling code. */
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void (* md_finish) (FILE *, int);
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/* Reorder insns in a machine-dependent fashion, in two different
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places. Default does nothing. */
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int (* reorder) (FILE *, int, rtx *, int *, int);
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int (* reorder2) (FILE *, int, rtx *, int *, int);
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/* The following member value is a pointer to a function called
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after evaluation forward dependencies of insns in chain given
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by two parameter values (head and tail correspondingly). */
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void (* dependencies_evaluation_hook) (rtx, rtx);
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/* The following member value is a pointer to a function returning
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nonzero if we should use DFA based scheduling. The default is
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to use the old pipeline scheduler. */
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int (* use_dfa_pipeline_interface) (void);
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/* The values of all the following members are used only for the
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DFA based scheduler: */
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/* The values of the following four members are pointers to
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functions used to simplify the automaton descriptions.
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dfa_pre_cycle_insn and dfa_post_cycle_insn give functions
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returning insns which are used to change the pipeline hazard
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recognizer state when the new simulated processor cycle
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correspondingly starts and finishes. The function defined by
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init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are used
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to initialize the corresponding insns. The default values of
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the members result in not changing the automaton state when
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the new simulated processor cycle correspondingly starts and
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finishes. */
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void (* init_dfa_pre_cycle_insn) (void);
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rtx (* dfa_pre_cycle_insn) (void);
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void (* init_dfa_post_cycle_insn) (void);
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rtx (* dfa_post_cycle_insn) (void);
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/* The following member value is a pointer to a function returning value
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which defines how many insns in queue `ready' will we try for
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multi-pass scheduling. if the member value is nonzero and the
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function returns positive value, the DFA based scheduler will make
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multi-pass scheduling for the first cycle. In other words, we will
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try to choose ready insn which permits to start maximum number of
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insns on the same cycle. */
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int (* first_cycle_multipass_dfa_lookahead) (void);
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/* The following member value is pointer to a function controlling
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what insns from the ready insn queue will be considered for the
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multipass insn scheduling. If the hook returns zero for insn
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passed as the parameter, the insn will be not chosen to be
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issued. */
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int (* first_cycle_multipass_dfa_lookahead_guard) (rtx);
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/* The following member value is pointer to a function called by
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the insn scheduler before issuing insn passed as the third
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parameter on given cycle. If the hook returns nonzero, the
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insn is not issued on given processors cycle. Instead of that,
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the processor cycle is advanced. If the value passed through
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the last parameter is zero, the insn ready queue is not sorted
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on the new cycle start as usually. The first parameter passes
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file for debugging output. The second one passes the scheduler
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verbose level of the debugging output. The forth and the fifth
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parameter values are correspondingly processor cycle on which
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the previous insn has been issued and the current processor
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cycle. */
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int (* dfa_new_cycle) (FILE *, int, rtx, int, int, int *);
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/* The values of the following members are pointers to functions
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used to improve the first cycle multipass scheduling by
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inserting nop insns. dfa_scheduler_bubble gives a function
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returning a nop insn with given index. The indexes start with
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zero. The function should return NULL if there are no more nop
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insns with indexes greater than given index. To initialize the
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nop insn the function given by member
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init_dfa_scheduler_bubbles is used. The default values of the
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members result in not inserting nop insns during the multipass
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scheduling. */
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void (* init_dfa_bubbles) (void);
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rtx (* dfa_bubble) (int);
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/* The following member value is a pointer to a function called
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by the insn scheduler. It should return true if there exists a
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dependence which is considered costly by the target, between
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the insn passed as the first parameter, and the insn passed as
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the second parameter. The third parameter is the INSN_DEPEND
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link that represents the dependence between the two insns. The
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fourth argument is the cost of the dependence as estimated by
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the scheduler. The last argument is the distance in cycles
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between the already scheduled insn (first parameter) and the
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the second insn (second parameter). */
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bool (* is_costly_dependence) (rtx, rtx, rtx, int, int);
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} sched;
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/* Given two decls, merge their attributes and return the result. */
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tree (* merge_decl_attributes) (tree, tree);
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/* Given two types, merge their attributes and return the result. */
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tree (* merge_type_attributes) (tree, tree);
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/* Table of machine attributes and functions to handle them.
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Ignored if NULL. */
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const struct attribute_spec *attribute_table;
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/* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
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one if they are compatible and two if they are nearly compatible
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(which causes a warning to be generated). */
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int (* comp_type_attributes) (tree type1, tree type2);
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/* Assign default attributes to the newly defined TYPE. */
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void (* set_default_type_attributes) (tree type);
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/* Insert attributes on the newly created DECL. */
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void (* insert_attributes) (tree decl, tree *attributes);
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/* Return true if FNDECL (which has at least one machine attribute)
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can be inlined despite its machine attributes, false otherwise. */
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bool (* function_attribute_inlinable_p) (tree fndecl);
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/* Return true if bitfields in RECORD_TYPE should follow the
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Microsoft Visual C++ bitfield layout rules. */
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bool (* ms_bitfield_layout_p) (tree record_type);
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/* Set up target-specific built-in functions. */
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void (* init_builtins) (void);
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/* Expand a target-specific builtin. */
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rtx (* expand_builtin) (tree exp, rtx target, rtx subtarget,
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enum machine_mode mode, int ignore);
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/* Make any adjustments to libfunc names needed for this target. */
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void (* init_libfuncs) (void);
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/* Given a decl, a section name, and whether the decl initializer
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has relocs, choose attributes for the section. */
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/* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
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unsigned int (* section_type_flags) (tree, const char *, int);
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/* True if new jumps cannot be created, to replace existing ones or
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not, at the current point in the compilation. */
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bool (* cannot_modify_jumps_p) (void);
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/* Return a register class for which branch target register
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optimizations should be applied. */
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int (* branch_target_register_class) (void);
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/* Return true if branch target register optimizations should include
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callee-saved registers that are not already live during the current
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function. AFTER_PE_GEN is true if prologues and epilogues have
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already been generated. */
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bool (* branch_target_register_callee_saved) (bool after_pe_gen);
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/* True if the constant X cannot be placed in the constant pool. */
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bool (* cannot_force_const_mem) (rtx);
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/* True if the insn X cannot be duplicated. */
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bool (* cannot_copy_insn_p) (rtx);
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/* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
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rtx (* delegitimize_address) (rtx);
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/* True if it is OK to do sibling call optimization for the specified
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call expression EXP. DECL will be the called function, or NULL if
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this is an indirect call. */
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bool (*function_ok_for_sibcall) (tree decl, tree exp);
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/* True if EXP should be placed in a "small data" section. */
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bool (* in_small_data_p) (tree);
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/* True if EXP names an object for which name resolution must resolve
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to the current module. */
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bool (* binds_local_p) (tree);
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/* Do something target-specific to record properties of the DECL into
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the associated SYMBOL_REF. */
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void (* encode_section_info) (tree, rtx, int);
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/* Undo the effects of encode_section_info on the symbol string. */
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const char * (* strip_name_encoding) (const char *);
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/* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
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bool (* valid_pointer_mode) (enum machine_mode mode);
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/* True if a vector is opaque. */
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bool (* vector_opaque_p) (tree);
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/* Compute a (partial) cost for rtx X. Return true if the complete
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cost has been computed, and false if subexpressions should be
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scanned. In either case, *TOTAL contains the cost result. */
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/* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
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not necessarily defined at this point. */
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bool (* rtx_costs) (rtx x, int code, int outer_code, int *total);
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/* Compute the cost of X, used as an address. Never called with
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invalid addresses. */
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int (* address_cost) (rtx x);
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/* Given a register, this hook should return a parallel of registers
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to represent where to find the register pieces. Define this hook
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if the register and its mode are represented in Dwarf in
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non-contiguous locations, or if the register should be
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represented in more than one register in Dwarf. Otherwise, this
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hook should return NULL_RTX. */
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rtx (* dwarf_register_span) (rtx);
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/* Fetch the fixed register(s) which hold condition codes, for
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targets where it makes sense to look for duplicate assignments to
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the condition codes. This should return true if there is such a
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register, false otherwise. The arguments should be set to the
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fixed register numbers. Up to two condition code registers are
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supported. If there is only one for this target, the int pointed
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at by the second argument should be set to -1. */
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bool (* fixed_condition_code_regs) (unsigned int *, unsigned int *);
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/* If two condition code modes are compatible, return a condition
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code mode which is compatible with both, such that a comparison
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done in the returned mode will work for both of the original
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modes. If the condition code modes are not compatible, return
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VOIDmode. */
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enum machine_mode (* cc_modes_compatible) (enum machine_mode,
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enum machine_mode);
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/* Do machine-dependent code transformations. Called just before
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delayed-branch scheduling. */
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void (* machine_dependent_reorg) (void);
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/* Create the __builtin_va_list type. */
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tree (* build_builtin_va_list) (void);
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/* Validity-checking routines for PCH files, target-specific.
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get_pch_validity returns a pointer to the data to be stored,
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and stores the size in its argument. pch_valid_p gets the same
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information back and returns NULL if the PCH is valid,
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or an error message if not.
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*/
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void * (* get_pch_validity) (size_t *);
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const char * (* pch_valid_p) (const void *, size_t);
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/* Functions relating to calls - argument passing, returns, etc. */
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struct calls {
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bool (*promote_function_args) (tree fntype);
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bool (*promote_function_return) (tree fntype);
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bool (*promote_prototypes) (tree fntype);
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rtx (*struct_value_rtx) (tree fndecl, int incoming);
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bool (*return_in_memory) (tree type, tree fndecl);
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bool (*return_in_msb) (tree type);
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rtx (*expand_builtin_saveregs) (void);
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/* Returns pretend_argument_size. */
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void (*setup_incoming_varargs) (CUMULATIVE_ARGS *ca, enum machine_mode mode,
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tree type, int *pretend_arg_size,
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int second_time);
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bool (*strict_argument_naming) (CUMULATIVE_ARGS *ca);
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/* Returns true if we should use SETUP_INCOMING_VARARGS and/or
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targetm.calls.strict_argument_naming(). */
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bool (*pretend_outgoing_varargs_named) (CUMULATIVE_ARGS *ca);
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/* Given a complex type T, return true if a parameter of type T
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should be passed as two scalars. */
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bool (* split_complex_arg) (tree type);
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} calls;
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/* Leave the boolean fields at the end. */
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/* True if arbitrary sections are supported. */
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bool have_named_sections;
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/* True if "native" constructors and destructors are supported,
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false if we're using collect2 for the job. */
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bool have_ctors_dtors;
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/* True if thread-local storage is supported. */
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bool have_tls;
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/* True if a small readonly data section is supported. */
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bool have_srodata_section;
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/* True if EH frame info sections should be zero-terminated. */
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bool terminate_dw2_eh_frame_info;
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/* True if #NO_APP should be emitted at the beginning of
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assembly output. */
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bool file_start_app_off;
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/* True if output_file_directive should be called for main_input_filename
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at the beginning of assembly output. */
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bool file_start_file_directive;
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/* Leave the boolean fields at the end. */
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};
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extern struct gcc_target targetm;
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