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ba715d7fe4
During debugging I get 10-30 seconds for a response to simple commands like: (gdb) print vectorvar.size() With this patch the performance gets to 1-2 seconds which is somehow acceptable. The problem is that dwarf2_gdb_index_functions.lookup_symbol (quick_symbol_functions::lookup_symbol) may return (and returns) NULL even for symbols which are present in .gdb_index but which can be found in already expanded symtab. But searching in the already expanded symtabs is just too slow when there are 400000+ expanded symtabs. There would be needed some single global hash table for each objfile so that one does not have to iterate all symtabs. Which .gdb_index could perfectly serve for, just its lookup_symbol() would need to return authoritative yes/no answers. Even after such fix these two simple patches are useful for example for non-.gdb_index files. One can reproduce the slugging interactive GDB performance with: #include <string> using namespace std; string var; class C { public: void m() {} }; int main() { C c; c.m(); return 0; } g++ -o slow slow.C -Wall -g $(pkg-config --libs gtkmm-3.0) gdb ./slow -ex 'b C::m' -ex 'maintenance set per-command space' -ex 'maintenance set per-command symtab' -ex 'maintenance set per-command time' -ex r [...] (gdb) p <tab><tab> Display all 183904 possibilities? (y or n) n (gdb) p/r var $1 = {static npos = <optimized out>, _M_dataplus = {<std::allocator<char>> = {<__gnu_cxx::new_allocator<char>> = {<No data fields>}, <No data fields>}, _M_p = 0x3a4db073d8 <std::string::_Rep::_S_empty_rep_storage+24> ""}} Command execution time: 20.023000 (cpu), 20.118665 (wall) ^^^^^^^^^ Space used: 927997952 (+0 for this command) Without DWZ there are X global blocks for X primary symtabs for X CUs of objfile. With DWZ there are X+Y global blocks for X+Y primary symtabs for X+Y CUs where Y are 'DW_TAG_partial_unit's. For 'DW_TAG_partial_unit's (Ys) their blockvector is usually empty. But not always, I have found there typedef symbols, there can IMO be optimized-out static variables etc. Neither of the patches should cause any visible behavior change. gdb/ChangeLog 2014-12-04 Jan Kratochvil <jan.kratochvil@redhat.com> * block.c (block_lookup_symbol_primary): New function. * block.h (block_lookup_symbol_primary): New declaration. * symtab.c (lookup_symbol_in_objfile_symtabs): Assert BLOCK_INDEX. Call block_lookup_symbol_primary.
306 lines
10 KiB
C
306 lines
10 KiB
C
/* Code dealing with blocks for GDB.
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Copyright (C) 2003-2014 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any 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, see <http://www.gnu.org/licenses/>. */
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#ifndef BLOCK_H
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#define BLOCK_H
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#include "dictionary.h"
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/* Opaque declarations. */
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struct symbol;
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struct compunit_symtab;
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struct block_namespace_info;
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struct using_direct;
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struct obstack;
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struct addrmap;
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/* All of the name-scope contours of the program
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are represented by `struct block' objects.
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All of these objects are pointed to by the blockvector.
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Each block represents one name scope.
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Each lexical context has its own block.
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The blockvector begins with some special blocks.
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The GLOBAL_BLOCK contains all the symbols defined in this compilation
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whose scope is the entire program linked together.
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The STATIC_BLOCK contains all the symbols whose scope is the
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entire compilation excluding other separate compilations.
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Blocks starting with the FIRST_LOCAL_BLOCK are not special.
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Each block records a range of core addresses for the code that
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is in the scope of the block. The STATIC_BLOCK and GLOBAL_BLOCK
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give, for the range of code, the entire range of code produced
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by the compilation that the symbol segment belongs to.
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The blocks appear in the blockvector
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in order of increasing starting-address,
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and, within that, in order of decreasing ending-address.
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This implies that within the body of one function
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the blocks appear in the order of a depth-first tree walk. */
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struct block
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{
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/* Addresses in the executable code that are in this block. */
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CORE_ADDR startaddr;
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CORE_ADDR endaddr;
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/* The symbol that names this block, if the block is the body of a
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function (real or inlined); otherwise, zero. */
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struct symbol *function;
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/* The `struct block' for the containing block, or 0 if none.
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The superblock of a top-level local block (i.e. a function in the
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case of C) is the STATIC_BLOCK. The superblock of the
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STATIC_BLOCK is the GLOBAL_BLOCK. */
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struct block *superblock;
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/* This is used to store the symbols in the block. */
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struct dictionary *dict;
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/* Used for language-specific info. */
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union
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{
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struct
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{
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/* Contains information about namespace-related info relevant to
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this block: using directives and the current namespace
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scope. */
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struct block_namespace_info *namespace;
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}
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cplus_specific;
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}
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language_specific;
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};
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/* The global block is singled out so that we can provide a back-link
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to the compunit symtab. */
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struct global_block
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{
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/* The block. */
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struct block block;
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/* This holds a pointer to the compunit symtab holding this block. */
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struct compunit_symtab *compunit_symtab;
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};
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#define BLOCK_START(bl) (bl)->startaddr
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#define BLOCK_END(bl) (bl)->endaddr
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#define BLOCK_FUNCTION(bl) (bl)->function
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#define BLOCK_SUPERBLOCK(bl) (bl)->superblock
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#define BLOCK_DICT(bl) (bl)->dict
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#define BLOCK_NAMESPACE(bl) (bl)->language_specific.cplus_specific.namespace
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struct blockvector
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{
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/* Number of blocks in the list. */
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int nblocks;
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/* An address map mapping addresses to blocks in this blockvector.
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This pointer is zero if the blocks' start and end addresses are
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enough. */
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struct addrmap *map;
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/* The blocks themselves. */
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struct block *block[1];
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};
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#define BLOCKVECTOR_NBLOCKS(blocklist) (blocklist)->nblocks
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#define BLOCKVECTOR_BLOCK(blocklist,n) (blocklist)->block[n]
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#define BLOCKVECTOR_MAP(blocklist) ((blocklist)->map)
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extern struct symbol *block_linkage_function (const struct block *);
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extern struct symbol *block_containing_function (const struct block *);
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extern int block_inlined_p (const struct block *block);
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extern int contained_in (const struct block *, const struct block *);
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extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
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const struct block **);
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extern const struct blockvector *
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blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
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const struct block **, struct compunit_symtab *);
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extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
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extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
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CORE_ADDR pc);
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extern const struct block *block_for_pc (CORE_ADDR);
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extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
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extern const char *block_scope (const struct block *block);
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extern void block_set_scope (struct block *block, const char *scope,
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struct obstack *obstack);
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extern struct using_direct *block_using (const struct block *block);
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extern void block_set_using (struct block *block,
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struct using_direct *using,
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struct obstack *obstack);
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extern const struct block *block_static_block (const struct block *block);
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extern const struct block *block_global_block (const struct block *block);
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extern struct block *allocate_block (struct obstack *obstack);
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extern struct block *allocate_global_block (struct obstack *obstack);
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extern void set_block_compunit_symtab (struct block *,
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struct compunit_symtab *);
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/* A block iterator. This structure should be treated as though it
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were opaque; it is only defined here because we want to support
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stack allocation of iterators. */
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struct block_iterator
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{
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/* If we're iterating over a single block, this holds the block.
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Otherwise, it holds the canonical compunit. */
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union
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{
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struct compunit_symtab *compunit_symtab;
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const struct block *block;
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} d;
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/* If we're iterating over a single block, this is always -1.
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Otherwise, it holds the index of the current "included" symtab in
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the canonical symtab (that is, d.symtab->includes[idx]), with -1
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meaning the canonical symtab itself. */
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int idx;
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/* Which block, either static or global, to iterate over. If this
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is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
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This is used to select which field of 'd' is in use. */
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enum block_enum which;
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/* The underlying dictionary iterator. */
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struct dict_iterator dict_iter;
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};
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/* Initialize ITERATOR to point at the first symbol in BLOCK, and
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return that first symbol, or NULL if BLOCK is empty. */
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extern struct symbol *block_iterator_first (const struct block *block,
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struct block_iterator *iterator);
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/* Advance ITERATOR, and return the next symbol, or NULL if there are
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no more symbols. Don't call this if you've previously received
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NULL from block_iterator_first or block_iterator_next on this
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iteration. */
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extern struct symbol *block_iterator_next (struct block_iterator *iterator);
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/* Initialize ITERATOR to point at the first symbol in BLOCK whose
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SYMBOL_SEARCH_NAME is NAME (as tested using strcmp_iw), and return
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that first symbol, or NULL if there are no such symbols. */
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extern struct symbol *block_iter_name_first (const struct block *block,
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const char *name,
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struct block_iterator *iterator);
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/* Advance ITERATOR to point at the next symbol in BLOCK whose
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SYMBOL_SEARCH_NAME is NAME (as tested using strcmp_iw), or NULL if
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there are no more such symbols. Don't call this if you've
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previously received NULL from block_iterator_first or
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block_iterator_next on this iteration. And don't call it unless
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ITERATOR was created by a previous call to block_iter_name_first
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with the same NAME. */
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extern struct symbol *block_iter_name_next (const char *name,
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struct block_iterator *iterator);
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/* Initialize ITERATOR to point at the first symbol in BLOCK whose
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SYMBOL_SEARCH_NAME is NAME, as tested using COMPARE (which must use
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the same conventions as strcmp_iw and be compatible with any
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block hashing function), and return that first symbol, or NULL
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if there are no such symbols. */
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extern struct symbol *block_iter_match_first (const struct block *block,
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const char *name,
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symbol_compare_ftype *compare,
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struct block_iterator *iterator);
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/* Advance ITERATOR to point at the next symbol in BLOCK whose
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SYMBOL_SEARCH_NAME is NAME, as tested using COMPARE (see
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block_iter_match_first), or NULL if there are no more such symbols.
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Don't call this if you've previously received NULL from
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block_iterator_match_first or block_iterator_match_next on this
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iteration. And don't call it unless ITERATOR was created by a
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previous call to block_iter_match_first with the same NAME and COMPARE. */
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extern struct symbol *block_iter_match_next (const char *name,
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symbol_compare_ftype *compare,
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struct block_iterator *iterator);
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/* Search BLOCK for symbol NAME in DOMAIN. */
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extern struct symbol *block_lookup_symbol (const struct block *block,
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const char *name,
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const domain_enum domain);
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/* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
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BLOCK. BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK. Function is useful if
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one iterates all global/static blocks of an objfile. */
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extern struct symbol *block_lookup_symbol_primary (const struct block *block,
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const char *name,
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const domain_enum domain);
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/* Macro to loop through all symbols in BLOCK, in no particular
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order. ITER helps keep track of the iteration, and must be a
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struct block_iterator. SYM points to the current symbol. */
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#define ALL_BLOCK_SYMBOLS(block, iter, sym) \
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for ((sym) = block_iterator_first ((block), &(iter)); \
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(sym); \
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(sym) = block_iterator_next (&(iter)))
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/* Macro to loop through all symbols with name NAME in BLOCK,
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in no particular order. ITER helps keep track of the iteration, and
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must be a struct block_iterator. SYM points to the current symbol. */
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#define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym) \
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for ((sym) = block_iter_name_first ((block), (name), &(iter)); \
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(sym) != NULL; \
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(sym) = block_iter_name_next ((name), &(iter)))
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#endif /* BLOCK_H */
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