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/* Data structures and declarations used for reading and writing

   GIMPLE to a file stream.

   Copyright (C) 2009, 2010, 2011 Free Software Foundation, Inc.

   Contributed by Doug Kwan <dougkwan@google.com>

This file is part of GCC.

GCC 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.

GCC 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 GCC; see the file COPYING3.  If not see

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

#ifndef GCC_LTO_STREAMER_H

#define GCC_LTO_STREAMER_H

#include "plugin-api.h"

#include "tree.h"

#include "gimple.h"

#include "target.h"

#include "cgraph.h"

#include "vec.h"

#include "vecprim.h"

#include "alloc-pool.h"

#include "gcov-io.h"

#include "diagnostic.h"

/* Define when debugging the LTO streamer.  This causes the writer

   to output the numeric value for the memory address of the tree node

   being emitted.  When debugging a problem in the reader, check the

   original address that the writer was emitting using lto_orig_address_get.

   With this value, set a breakpoint in the writer (e.g., lto_output_tree)

   to trace how the faulty node is being emitted.  */

/* #define LTO_STREAMER_DEBUG   1  */

/* The encoding for a function consists of the following sections:

   1)    The header.

   2)    FIELD_DECLS.

   3)    FUNCTION_DECLS.

   4)    global VAR_DECLS.

   5)    type_decls

   6)    types.

   7)    Names for the labels that have names

   8)    The SSA names.

   9)    The control flow graph.

   10-11)Gimple for local decls.

   12)   Gimple for the function.

   13)   Strings.

   1) THE HEADER.

   2-6) THE GLOBAL DECLS AND TYPES.

      The global decls and types are encoded in the same way.  For each

      entry, there is word with the offset within the section to the

      entry.

   7) THE LABEL NAMES.

      Since most labels do not have names, this section my be of zero

      length.  It consists of an array of string table references, one

      per label.  In the lto code, the labels are given either

      positive or negative indexes.  the positive ones have names and

      the negative ones do not.  The positive index can be used to

      find the name in this array.

   9) THE CFG.

   10) Index into the local decls.  Since local decls can have local

      decls inside them, they must be read in randomly in order to

      properly restore them.

   11-12) GIMPLE FOR THE LOCAL DECLS AND THE FUNCTION BODY.

     The gimple consists of a set of records.

     THE FUNCTION

     At the top level of (8) is the function. It consists of five

     pieces:

     LTO_function     - The tag.

     eh tree          - This is all of the exception handling regions

                        put out in a post order traversial of the

                        tree.  Siblings are output as lists terminated

                        by a 0.  The set of fields matches the fields

                        defined in except.c.

     last_basic_block - in uleb128 form.

     basic blocks     - This is the set of basic blocks.

     zero             - The termination of the basic blocks.

     BASIC BLOCKS

     There are two forms of basic blocks depending on if they are

     empty or not.

     The basic block consists of:

     LTO_bb1 or LTO_bb0 - The tag.

     bb->index          - the index in uleb128 form.

     #succs             - The number of successors un uleb128 form.

     the successors     - For each edge, a pair.  The first of the

                          pair is the index of the successor in

                          uleb128 form and the second are the flags in

                          uleb128 form.

     the statements     - A gimple tree, as described above.

                          These are only present for LTO_BB1.

                          Following each statement is an optional

                          exception handling record LTO_eh_region

                          which contains the region number (for

                          regions >= 0).

     zero               - This is only present for LTO_BB1 and is used

                          to terminate the statements and exception

                          regions within this block.

   12) STRINGS

     String are represented in the table as pairs, a length in ULEB128

     form followed by the data for the string.  */

/* The string that is the prefix on the section names we make for lto.

   For decls the DECL_ASSEMBLER_NAME is appended to make the section

   name for the functions and static_initializers.  For other types of

   sections a '.' and the section type are appended.  */

#define LTO_SECTION_NAME_PREFIX         ".gnu.lto_"

#define LTO_major_version 2

#define LTO_minor_version 1

typedef unsigned char   lto_decl_flags_t;

/* Tags representing the various IL objects written to the bytecode file

   (GIMPLE statements, basic blocks, EH regions, tree nodes, etc).

   NOTE, when adding new LTO tags, also update lto_tag_name.  */

enum LTO_tags

{

  LTO_null = 0,

  /* Reserve enough entries to fit all the tree and gimple codes handled

     by the streamer.  This guarantees that:

     1- Given a tree code C:

                enum LTO_tags tag == C + 1

     2- Given a gimple code C:

                enum LTO_tags tag == C + NUM_TREE_CODES + 1

     Conversely, to map between LTO tags and tree/gimple codes, the

     reverse operation must be applied.  */

  LTO_bb0 = 1 + MAX_TREE_CODES + LAST_AND_UNUSED_GIMPLE_CODE,

  LTO_bb1,

  /* EH region holding the previous statement.  */

  LTO_eh_region,

  /* An MD or NORMAL builtin.  Only the code and class are streamed out.  */

  LTO_builtin_decl,

  /* Function body.  */

  LTO_function,

  /* EH table.  */

  LTO_eh_table,

  /* EH region types.  These mirror enum eh_region_type.  */

  LTO_ert_cleanup,

  LTO_ert_try,

  LTO_ert_allowed_exceptions,

  LTO_ert_must_not_throw,

  /* EH landing pad.  */

  LTO_eh_landing_pad,

  /* EH try/catch node.  */

  LTO_eh_catch,

  /* Special for global streamer. Reference to previously-streamed node.  */

  LTO_tree_pickle_reference,

  /* References to indexable tree nodes.  These objects are stored in

     tables that are written separately from the function bodies that

     reference them.  This way they can be instantiated even when the

     referencing functions aren't (e.g., during WPA) and it also allows

     functions to be copied from one file to another without having

     to unpickle the body first (the references are location

     independent).

     NOTE, do not regroup these values as the grouping is exposed

     in the range checks done in lto_input_tree.  */

  LTO_field_decl_ref,                   /* Do not change.  */

  LTO_function_decl_ref,

  LTO_label_decl_ref,

  LTO_namespace_decl_ref,

  LTO_result_decl_ref,

  LTO_ssa_name_ref,

  LTO_type_decl_ref,

  LTO_type_ref,

  LTO_const_decl_ref,

  LTO_imported_decl_ref,

  LTO_translation_unit_decl_ref,

  LTO_global_decl_ref,                  /* Do not change.  */

  /* This tag must always be last.  */

  LTO_NUM_TAGS

};

/* Set of section types that are in an LTO file.  This list will grow

   as the number of IPA passes grows since each IPA pass will need its

   own section type to store its summary information.

   When adding a new section type, you must also extend the

   LTO_SECTION_NAME array in lto-section-in.c.  */

enum lto_section_type

{

  LTO_section_decls = 0,

  LTO_section_function_body,

  LTO_section_static_initializer,

  LTO_section_cgraph,

  LTO_section_varpool,

  LTO_section_refs,

  LTO_section_asm,

  LTO_section_jump_functions,

  LTO_section_ipa_pure_const,

  LTO_section_ipa_reference,

  LTO_section_symtab,

  LTO_section_opts,

  LTO_section_cgraph_opt_sum,

  LTO_section_inline_summary,

  LTO_N_SECTION_TYPES           /* Must be last.  */

};

/* Indices to the various function, type and symbol streams. */

typedef enum

{

  LTO_DECL_STREAM_TYPE = 0,              /* Must be first. */

  LTO_DECL_STREAM_FIELD_DECL,

  LTO_DECL_STREAM_FN_DECL,

  LTO_DECL_STREAM_VAR_DECL,

  LTO_DECL_STREAM_TYPE_DECL,

  LTO_DECL_STREAM_NAMESPACE_DECL,

  LTO_DECL_STREAM_LABEL_DECL,

  LTO_N_DECL_STREAMS

} lto_decl_stream_e_t;

typedef enum ld_plugin_symbol_resolution ld_plugin_symbol_resolution_t;

DEF_VEC_I(ld_plugin_symbol_resolution_t);

DEF_VEC_ALLOC_I(ld_plugin_symbol_resolution_t, heap);

/* Macro to define convenience functions for type and decl streams

   in lto_file_decl_data.  */

#define DEFINE_DECL_STREAM_FUNCS(UPPER_NAME, name) \

static inline tree \

lto_file_decl_data_get_ ## name (struct lto_file_decl_data *data, \

                                 unsigned int idx) \

{ \

  struct lto_in_decl_state *state = data->current_decl_state; \

  gcc_assert (idx < state->streams[LTO_DECL_STREAM_## UPPER_NAME].size); \

  return state->streams[LTO_DECL_STREAM_## UPPER_NAME].trees[idx]; \

} \

\

static inline unsigned int \

lto_file_decl_data_num_ ## name ## s (struct lto_file_decl_data *data) \

{ \

  struct lto_in_decl_state *state = data->current_decl_state; \

  return state->streams[LTO_DECL_STREAM_## UPPER_NAME].size; \

}

/* Return a char pointer to the start of a data stream for an lto pass

   or function.  The first parameter is the file data that contains

   the information.  The second parameter is the type of information

   to be obtained.  The third parameter is the name of the function

   and is only used when finding a function body; otherwise it is

   NULL.  The fourth parameter is the length of the data returned.  */

typedef const char* (lto_get_section_data_f) (struct lto_file_decl_data *,

                                              enum lto_section_type,

                                              const char *,

                                              size_t *);

/* Return the data found from the above call.  The first three

   parameters are the same as above.  The fourth parameter is the data

   itself and the fifth is the lenght of the data. */

typedef void (lto_free_section_data_f) (struct lto_file_decl_data *,

                                        enum lto_section_type,

                                        const char *,

                                        const char *,

                                        size_t);

/* Structure used as buffer for reading an LTO file.  */

struct lto_input_block

{

  const char *data;

  unsigned int p;

  unsigned int len;

};

#define LTO_INIT_INPUT_BLOCK(BASE,D,P,L)   \

  do {                                     \

    BASE.data = D;                         \

    BASE.p = P;                            \

    BASE.len = L;                          \

  } while (0)

#define LTO_INIT_INPUT_BLOCK_PTR(BASE,D,P,L) \

  do {                                       \

    BASE->data = D;                          \

    BASE->p = P;                             \

    BASE->len = L;                           \

  } while (0)

/* The is the first part of the record for a function or constructor

   in the .o file.  */

struct lto_header

{

  int16_t major_version;

  int16_t minor_version;

  enum lto_section_type section_type;

};

/* The header for a function body.  */

struct lto_function_header

{

  /* The header for all types of sections. */

  struct lto_header lto_header;

  /* Number of labels with names.  */

  int32_t num_named_labels;

  /* Number of labels without names.  */

  int32_t num_unnamed_labels;

  /* Size compressed or 0 if not compressed.  */

  int32_t compressed_size;

  /* Size of names for named labels.  */

  int32_t named_label_size;

  /* Size of the cfg.  */

  int32_t cfg_size;

  /* Size of main gimple body of function.  */

  int32_t main_size;

  /* Size of the string table.  */

  int32_t string_size;

};

/* Structure describing a symbol section.  */

struct lto_decl_header

{

  /* The header for all types of sections. */

  struct lto_header lto_header;

  /* Size of region for decl state. */

  int32_t decl_state_size;

  /* Number of nodes in globals stream.  */

  int32_t num_nodes;

  /* Size of region for expressions, decls, types, etc. */

  int32_t main_size;

  /* Size of the string table.  */

  int32_t string_size;

};

/* Structure describing top level asm()s.  */

struct lto_asm_header

{

  /* The header for all types of sections. */

  struct lto_header lto_header;

  /* Size compressed or 0 if not compressed.  */

  int32_t compressed_size;

  /* Size of region for expressions, decls, types, etc. */

  int32_t main_size;

  /* Size of the string table.  */

  int32_t string_size;

};

/* Statistics gathered during LTO, WPA and LTRANS.  */

struct lto_stats_d

{

  unsigned HOST_WIDE_INT num_input_cgraph_nodes;

  unsigned HOST_WIDE_INT num_output_cgraph_nodes;

  unsigned HOST_WIDE_INT num_input_files;

  unsigned HOST_WIDE_INT num_output_files;

  unsigned HOST_WIDE_INT num_cgraph_partitions;

  unsigned HOST_WIDE_INT section_size[LTO_N_SECTION_TYPES];

  unsigned HOST_WIDE_INT num_function_bodies;

  unsigned HOST_WIDE_INT num_trees[NUM_TREE_CODES];

  unsigned HOST_WIDE_INT num_output_il_bytes;

  unsigned HOST_WIDE_INT num_compressed_il_bytes;

  unsigned HOST_WIDE_INT num_input_il_bytes;

  unsigned HOST_WIDE_INT num_uncompressed_il_bytes;

};

/* Encoder data structure used to stream callgraph nodes.  */

struct lto_cgraph_encoder_d

{

  /* Map nodes to reference number. */

  struct pointer_map_t *map;

  /* Map reference number to node. */

  VEC(cgraph_node_ptr,heap) *nodes;

  /* Map of nodes where we want to output body.  */

  struct pointer_set_t *body;

};

typedef struct lto_cgraph_encoder_d *lto_cgraph_encoder_t;

/* Return number of encoded nodes in ENCODER.  */

static inline int

lto_cgraph_encoder_size (lto_cgraph_encoder_t encoder)

{

  return VEC_length (cgraph_node_ptr, encoder->nodes);

}

/* Encoder data structure used to stream callgraph nodes.  */

struct lto_varpool_encoder_d

{

  /* Map nodes to reference number. */

  struct pointer_map_t *map;

  /* Map reference number to node. */

  VEC(varpool_node_ptr,heap) *nodes;

  /* Map of nodes where we want to output initializer.  */

  struct pointer_set_t *initializer;

};

typedef struct lto_varpool_encoder_d *lto_varpool_encoder_t;

/* Return number of encoded nodes in ENCODER.  */

static inline int

lto_varpool_encoder_size (lto_varpool_encoder_t encoder)

{

  return VEC_length (varpool_node_ptr, encoder->nodes);

}

/* Mapping from indices to trees.  */

struct GTY(()) lto_tree_ref_table

{

  /* Array of referenced trees . */

  tree * GTY((length ("%h.size"))) trees;

  /* Size of array. */

  unsigned int size;

};

/* Mapping between trees and slots in an array.  */

struct lto_decl_slot

{

  tree t;

  int slot_num;

};

/* The lto_tree_ref_encoder struct is used to encode trees into indices. */

struct lto_tree_ref_encoder

{

  htab_t tree_hash_table;       /* Maps pointers to indices. */

  unsigned int next_index;      /* Next available index. */

  VEC(tree,heap) *trees;        /* Maps indices to pointers. */

};

/* Structure to hold states of input scope.  */

struct GTY(()) lto_in_decl_state

{

  /* Array of lto_in_decl_buffers to store type and decls streams. */

  struct lto_tree_ref_table streams[LTO_N_DECL_STREAMS];

  /* If this in-decl state is associated with a function. FN_DECL

     point to the FUNCTION_DECL. */

  tree fn_decl;

};

typedef struct lto_in_decl_state *lto_in_decl_state_ptr;

/* The structure that holds all of the vectors of global types,

   decls and cgraph nodes used in the serialization of this file.  */

struct lto_out_decl_state

{

  /* The buffers contain the sets of decls of various kinds and types we have

     seen so far and the indexes assigned to them.  */

  struct lto_tree_ref_encoder streams[LTO_N_DECL_STREAMS];

  /* Encoder for cgraph nodes.  */

  lto_cgraph_encoder_t cgraph_node_encoder;

  /* Encoder for varpool nodes.  */

  lto_varpool_encoder_t varpool_node_encoder;

  /* If this out-decl state belongs to a function, fn_decl points to that

     function.  Otherwise, it is NULL. */

  tree fn_decl;

};

typedef struct lto_out_decl_state *lto_out_decl_state_ptr;

DEF_VEC_P(lto_out_decl_state_ptr);

DEF_VEC_ALLOC_P(lto_out_decl_state_ptr, heap);

/* One of these is allocated for each object file that being compiled

   by lto.  This structure contains the tables that are needed by the

   serialized functions and ipa passes to connect themselves to the

   global types and decls as they are reconstituted.  */

struct GTY(()) lto_file_decl_data

{

  /* Decl state currently used. */

  struct lto_in_decl_state *current_decl_state;

  /* Decl state corresponding to regions outside of any functions

     in the compilation unit. */

  struct lto_in_decl_state *global_decl_state;

  /* Table of cgraph nodes present in this file.  */

  lto_cgraph_encoder_t GTY((skip)) cgraph_node_encoder;

  /* Table of varpool nodes present in this file.  */

  lto_varpool_encoder_t GTY((skip)) varpool_node_encoder;

  /* Hash table maps lto-related section names to location in file.  */

  htab_t GTY((param_is (struct lto_in_decl_state))) function_decl_states;

  /* The .o file that these offsets relate to.  */

  const char *GTY((skip)) file_name;

  /* Hash table maps lto-related section names to location in file.  */

  htab_t GTY((skip)) section_hash_table;

  /* Hash new name of renamed global declaration to its original name.  */

  htab_t GTY((skip)) renaming_hash_table;

  /* Linked list used temporarily in reader */

  struct lto_file_decl_data *next;

  /* Sub ID for merged objects. */

  unsigned HOST_WIDE_INT id;

  /* Symbol resolutions for this file */

  VEC(ld_plugin_symbol_resolution_t,heap) * GTY((skip)) resolutions;

  struct gcov_ctr_summary GTY((skip)) profile_info;

};

typedef struct lto_file_decl_data *lto_file_decl_data_ptr;

struct lto_char_ptr_base

{

  char *ptr;

};

/* An incore byte stream to buffer the various parts of the function.

   The entire structure should be zeroed when created.  The record

   consists of a set of blocks.  The first sizeof (ptr) bytes are used

   as a chain, and the rest store the bytes to be written.  */

struct lto_output_stream

{

  /* The pointer to the first block in the stream.  */

  struct lto_char_ptr_base * first_block;

  /* The pointer to the last and current block in the stream.  */

  struct lto_char_ptr_base * current_block;

  /* The pointer to where the next char should be written.  */

  char * current_pointer;

  /* The number of characters left in the current block.  */

  unsigned int left_in_block;

  /* The block size of the last block allocated.  */

  unsigned int block_size;

  /* The total number of characters written.  */

  unsigned int total_size;

};

/* The is the first part of the record in an LTO file for many of the

   IPA passes.  */

struct lto_simple_header

{

  /* The header for all types of sections. */

  struct lto_header lto_header;

  /* Size of main gimple body of function.  */

  int32_t main_size;

  /* Size of main stream when compressed.  */

  int32_t compressed_size;

};

/* A simple output block.  This can be used for simple IPA passes that

   do not need more than one stream.  */

struct lto_simple_output_block

{

  enum lto_section_type section_type;

  struct lto_out_decl_state *decl_state;

  /* The stream that the main tree codes are written to.  */

  struct lto_output_stream *main_stream;

};

/* Data structure holding all the data and descriptors used when writing

   an LTO file.  */

struct output_block

{

  enum lto_section_type section_type;

  struct lto_out_decl_state *decl_state;

  /* The stream that the main tree codes are written to.  */

  struct lto_output_stream *main_stream;

  /* The stream that contains the string table.  */

  struct lto_output_stream *string_stream;

  /* The stream that contains the cfg.  */

  struct lto_output_stream *cfg_stream;

  /* The hash table that contains the set of strings we have seen so

     far and the indexes assigned to them.  */

  htab_t string_hash_table;

  /* The current cgraph_node that we are currently serializing.  Null

     if we are serializing something else.  */

  struct cgraph_node *cgraph_node;

  /* These are the last file and line that were seen in the stream.

     If the current node differs from these, it needs to insert

     something into the stream and fix these up.  */

  const char *current_file;

  int current_line;

  int current_col;

  /* True if writing globals and types.  */

  bool global;

  /* Cache of nodes written in this section.  */

  struct streamer_tree_cache_d *writer_cache;

  /* All data persistent across whole duration of output block

     can go here.  */

  struct obstack obstack;

};

/* Data and descriptors used when reading from an LTO file.  */

struct data_in

{

  /* The global decls and types.  */

  struct lto_file_decl_data *file_data;

  /* All of the labels.  */

  tree *labels;

  /* The string table.  */

  const char *strings;

  /* The length of the string table.  */

  unsigned int strings_len;

  /* Number of named labels.  Used to find the index of unnamed labels

     since they share space with the named labels.  */

  unsigned int num_named_labels;

  /* Number of unnamed labels.  */

  unsigned int num_unnamed_labels;

  const char *current_file;

  int current_line;

  int current_col;

  /* Maps each reference number to the resolution done by the linker. */

  VEC(ld_plugin_symbol_resolution_t,heap) *globals_resolution;

  /* Cache of pickled nodes.  */

  struct streamer_tree_cache_d *reader_cache;

};

/* In lto-section-in.c  */

extern struct lto_input_block * lto_create_simple_input_block (

                               struct lto_file_decl_data *,

                               enum lto_section_type, const char **, size_t *);

extern void

lto_destroy_simple_input_block (struct lto_file_decl_data *,

                                enum lto_section_type,

                                struct lto_input_block *, const char *, size_t);

extern void lto_set_in_hooks (struct lto_file_decl_data **,

                              lto_get_section_data_f *,

                              lto_free_section_data_f *);

extern struct lto_file_decl_data **lto_get_file_decl_data (void);

extern const char *lto_get_section_data (struct lto_file_decl_data *,

                                         enum lto_section_type,

                                         const char *, size_t *);

extern void lto_free_section_data (struct lto_file_decl_data *,

                                   enum lto_section_type,

                                   const char *, const char *, size_t);

extern htab_t lto_create_renaming_table (void);

extern void lto_record_renamed_decl (struct lto_file_decl_data *,

                                     const char *, const char *);

extern const char *lto_get_decl_name_mapping (struct lto_file_decl_data *,

                                              const char *);

extern struct lto_in_decl_state *lto_new_in_decl_state (void);

extern void lto_delete_in_decl_state (struct lto_in_decl_state *);

extern hashval_t lto_hash_in_decl_state (const void *);

extern int lto_eq_in_decl_state (const void *, const void *);

extern struct lto_in_decl_state *lto_get_function_in_decl_state (

                                      struct lto_file_decl_data *, tree);

extern void lto_section_overrun (struct lto_input_block *) ATTRIBUTE_NORETURN;

extern void lto_value_range_error (const char *,

                                   HOST_WIDE_INT, HOST_WIDE_INT,

                                   HOST_WIDE_INT) ATTRIBUTE_NORETURN;

/* In lto-section-out.c  */

extern hashval_t lto_hash_decl_slot_node (const void *);

extern int lto_eq_decl_slot_node (const void *, const void *);

extern hashval_t lto_hash_type_slot_node (const void *);

extern int lto_eq_type_slot_node (const void *, const void *);

extern void lto_begin_section (const char *, bool);

extern void lto_end_section (void);

extern void lto_write_stream (struct lto_output_stream *);

extern void lto_output_data_stream (struct lto_output_stream *, const void *,

                                    size_t);

extern bool lto_output_decl_index (struct lto_output_stream *,

                            struct lto_tree_ref_encoder *,

                            tree, unsigned int *);

extern void lto_output_field_decl_index (struct lto_out_decl_state *,

                                  struct lto_output_stream *, tree);

extern void lto_output_fn_decl_index (struct lto_out_decl_state *,

                               struct lto_output_stream *, tree);

extern void lto_output_namespace_decl_index (struct lto_out_decl_state *,

                                      struct lto_output_stream *, tree);

extern void lto_output_var_decl_index (struct lto_out_decl_state *,

                                struct lto_output_stream *, tree);

extern void lto_output_type_decl_index (struct lto_out_decl_state *,

                                 struct lto_output_stream *, tree);

extern void lto_output_type_ref_index (struct lto_out_decl_state *,

                                struct lto_output_stream *, tree);

extern struct lto_simple_output_block *lto_create_simple_output_block (

                                enum lto_section_type);

extern void lto_destroy_simple_output_block (struct lto_simple_output_block *);

extern struct lto_out_decl_state *lto_new_out_decl_state (void);

extern void lto_delete_out_decl_state (struct lto_out_decl_state *);

extern struct lto_out_decl_state *lto_get_out_decl_state (void);

extern void lto_push_out_decl_state (struct lto_out_decl_state *);

extern struct lto_out_decl_state *lto_pop_out_decl_state (void);