mirrored from git://gcc.gnu.org/git/gcc.git
/
varasm.cc
8706 lines (7442 loc) · 253 KB
/
varasm.cc
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/* Output variables, constants and external declarations, for GNU compiler.
Copyright (C) 1987-2024 Free Software Foundation, Inc.
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/>. */
/* This file handles generation of all the assembler code
*except* the instructions of a function.
This includes declarations of variables and their initial values.
We also output the assembler code for constants stored in memory
and are responsible for combining constants with the same value. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "target.h"
#include "rtl.h"
#include "tree.h"
#include "predict.h"
#include "memmodel.h"
#include "tm_p.h"
#include "stringpool.h"
#include "regs.h"
#include "emit-rtl.h"
#include "cgraph.h"
#include "diagnostic-core.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "varasm.h"
#include "version.h"
#include "flags.h"
#include "stmt.h"
#include "expr.h"
#include "expmed.h"
#include "optabs.h"
#include "output.h"
#include "langhooks.h"
#include "debug.h"
#include "common/common-target.h"
#include "stringpool.h"
#include "attribs.h"
#include "asan.h"
#include "rtl-iter.h"
#include "file-prefix-map.h" /* remap_debug_filename() */
#include "alloc-pool.h"
#include "toplev.h"
#include "opts.h"
#include "asan.h"
/* The (assembler) name of the first globally-visible object output. */
extern GTY(()) const char *first_global_object_name;
extern GTY(()) const char *weak_global_object_name;
const char *first_global_object_name;
const char *weak_global_object_name;
class addr_const;
class constant_descriptor_rtx;
struct rtx_constant_pool;
#define n_deferred_constants (crtl->varasm.deferred_constants)
/* Number for making the label on the next
constant that is stored in memory. */
static GTY(()) int const_labelno;
/* Carry information from ASM_DECLARE_OBJECT_NAME
to ASM_FINISH_DECLARE_OBJECT. */
int size_directive_output;
/* The last decl for which assemble_variable was called,
if it did ASM_DECLARE_OBJECT_NAME.
If the last call to assemble_variable didn't do that,
this holds 0. */
tree last_assemble_variable_decl;
/* The following global variable indicates if the first basic block
in a function belongs to the cold partition or not. */
bool first_function_block_is_cold;
/* Whether we saw any functions with no_split_stack. */
static bool saw_no_split_stack;
static const char *strip_reg_name (const char *);
static bool contains_pointers_p (tree);
#ifdef ASM_OUTPUT_EXTERNAL
static bool incorporeal_function_p (tree);
#endif
static void decode_addr_const (tree, class addr_const *);
static hashval_t const_hash_1 (const tree);
static bool compare_constant (const tree, const tree);
static void output_constant_def_contents (rtx);
static void output_addressed_constants (tree, int);
static unsigned HOST_WIDE_INT output_constant (tree, unsigned HOST_WIDE_INT,
unsigned int, bool, bool);
static void globalize_decl (tree);
static bool decl_readonly_section_1 (enum section_category);
#ifdef BSS_SECTION_ASM_OP
#ifdef ASM_OUTPUT_ALIGNED_BSS
static void asm_output_aligned_bss (FILE *, tree, const char *,
unsigned HOST_WIDE_INT, int)
ATTRIBUTE_UNUSED;
#endif
#endif /* BSS_SECTION_ASM_OP */
static void mark_weak (tree);
static void output_constant_pool (const char *, tree);
static void handle_vtv_comdat_section (section *, const_tree);
/* Well-known sections, each one associated with some sort of *_ASM_OP. */
section *text_section;
section *data_section;
section *readonly_data_section;
section *sdata_section;
section *ctors_section;
section *dtors_section;
section *bss_section;
section *sbss_section;
/* Various forms of common section. All are guaranteed to be nonnull. */
section *tls_comm_section;
section *comm_section;
section *lcomm_section;
/* A SECTION_NOSWITCH section used for declaring global BSS variables.
May be null. */
section *bss_noswitch_section;
/* The section that holds the main exception table, when known. The section
is set either by the target's init_sections hook or by the first call to
switch_to_exception_section. */
section *exception_section;
/* The section that holds the DWARF2 frame unwind information, when known.
The section is set either by the target's init_sections hook or by the
first call to switch_to_eh_frame_section. */
section *eh_frame_section;
/* asm_out_file's current section. This is NULL if no section has yet
been selected or if we lose track of what the current section is. */
section *in_section;
/* True if code for the current function is currently being directed
at the cold section. */
bool in_cold_section_p;
/* The following global holds the "function name" for the code in the
cold section of a function, if hot/cold function splitting is enabled
and there was actually code that went into the cold section. A
pseudo function name is needed for the cold section of code for some
debugging tools that perform symbolization. */
tree cold_function_name = NULL_TREE;
/* A linked list of all the unnamed sections. */
static GTY(()) section *unnamed_sections;
/* Return a nonzero value if DECL has a section attribute. */
#define IN_NAMED_SECTION(DECL) \
(VAR_OR_FUNCTION_DECL_P (DECL) && DECL_SECTION_NAME (DECL) != NULL)
struct section_hasher : ggc_ptr_hash<section>
{
typedef const char *compare_type;
static hashval_t hash (section *);
static bool equal (section *, const char *);
};
/* Hash table of named sections. */
static GTY(()) hash_table<section_hasher> *section_htab;
struct object_block_hasher : ggc_ptr_hash<object_block>
{
typedef const section *compare_type;
static hashval_t hash (object_block *);
static bool equal (object_block *, const section *);
};
/* A table of object_blocks, indexed by section. */
static GTY(()) hash_table<object_block_hasher> *object_block_htab;
/* The next number to use for internal anchor labels. */
static GTY(()) int anchor_labelno;
/* A pool of constants that can be shared between functions. */
static GTY(()) struct rtx_constant_pool *shared_constant_pool;
/* Helper routines for maintaining section_htab. */
bool
section_hasher::equal (section *old, const char *new_name)
{
return strcmp (old->named.name, new_name) == 0;
}
hashval_t
section_hasher::hash (section *old)
{
return htab_hash_string (old->named.name);
}
/* Return a hash value for section SECT. */
static hashval_t
hash_section (section *sect)
{
if (sect->common.flags & SECTION_NAMED)
return htab_hash_string (sect->named.name);
return sect->common.flags & ~SECTION_DECLARED;
}
/* Helper routines for maintaining object_block_htab. */
inline bool
object_block_hasher::equal (object_block *old, const section *new_section)
{
return old->sect == new_section;
}
hashval_t
object_block_hasher::hash (object_block *old)
{
return hash_section (old->sect);
}
/* Return a new unnamed section with the given fields. */
section *
get_unnamed_section (unsigned int flags, void (*callback) (const char *),
const char *data)
{
section *sect;
sect = ggc_alloc<section> ();
sect->unnamed.common.flags = flags | SECTION_UNNAMED;
sect->unnamed.callback = callback;
sect->unnamed.data = data;
sect->unnamed.next = unnamed_sections;
unnamed_sections = sect;
return sect;
}
/* Return a SECTION_NOSWITCH section with the given fields. */
static section *
get_noswitch_section (unsigned int flags, noswitch_section_callback callback)
{
section *sect;
sect = ggc_alloc<section> ();
sect->noswitch.common.flags = flags | SECTION_NOSWITCH;
sect->noswitch.callback = callback;
return sect;
}
/* Return the named section structure associated with NAME. Create
a new section with the given fields if no such structure exists.
When NOT_EXISTING, then fail if the section already exists. Return
the existing section if the SECTION_RETAIN bit doesn't match. Set
the SECTION_WRITE | SECTION_RELRO bits on the existing section
if one of the section flags is SECTION_WRITE | SECTION_RELRO and the
other has none of these flags in named sections and either the section
hasn't been declared yet or has been declared as writable. */
section *
get_section (const char *name, unsigned int flags, tree decl,
bool not_existing)
{
section *sect, **slot;
slot = section_htab->find_slot_with_hash (name, htab_hash_string (name),
INSERT);
flags |= SECTION_NAMED;
if (decl != nullptr
&& DECL_P (decl)
&& lookup_attribute ("retain", DECL_ATTRIBUTES (decl)))
flags |= SECTION_RETAIN;
if (*slot == NULL)
{
sect = ggc_alloc<section> ();
sect->named.common.flags = flags;
sect->named.name = ggc_strdup (name);
sect->named.decl = decl;
*slot = sect;
}
else
{
if (not_existing)
internal_error ("section already exists: %qs", name);
sect = *slot;
/* It is fine if one of the sections has SECTION_NOTYPE as long as
the other has none of the contrary flags (see the logic at the end
of default_section_type_flags, below). */
if (((sect->common.flags ^ flags) & SECTION_NOTYPE)
&& !((sect->common.flags | flags)
& (SECTION_CODE | SECTION_BSS | SECTION_TLS | SECTION_ENTSIZE
| (HAVE_COMDAT_GROUP ? SECTION_LINKONCE : 0))))
{
sect->common.flags |= SECTION_NOTYPE;
flags |= SECTION_NOTYPE;
}
if ((sect->common.flags & ~SECTION_DECLARED) != flags
&& ((sect->common.flags | flags) & SECTION_OVERRIDE) == 0)
{
/* It is fine if one of the section flags is
SECTION_WRITE | SECTION_RELRO and the other has none of these
flags (i.e. read-only) in named sections and either the
section hasn't been declared yet or has been declared as writable.
In that case just make sure the resulting flags are
SECTION_WRITE | SECTION_RELRO, ie. writable only because of
relocations. */
if (((sect->common.flags ^ flags) & (SECTION_WRITE | SECTION_RELRO))
== (SECTION_WRITE | SECTION_RELRO)
&& (sect->common.flags
& ~(SECTION_DECLARED | SECTION_WRITE | SECTION_RELRO))
== (flags & ~(SECTION_WRITE | SECTION_RELRO))
&& ((sect->common.flags & SECTION_DECLARED) == 0
|| (sect->common.flags & SECTION_WRITE)))
{
sect->common.flags |= (SECTION_WRITE | SECTION_RELRO);
return sect;
}
/* If the SECTION_RETAIN bit doesn't match, return and switch
to a new section later. */
if ((sect->common.flags & SECTION_RETAIN)
!= (flags & SECTION_RETAIN))
return sect;
/* Sanity check user variables for flag changes. */
if (sect->named.decl != NULL
&& DECL_P (sect->named.decl)
&& decl != sect->named.decl)
{
if (decl != NULL && DECL_P (decl))
error ("%+qD causes a section type conflict with %qD",
decl, sect->named.decl);
else
error ("section type conflict with %qD", sect->named.decl);
inform (DECL_SOURCE_LOCATION (sect->named.decl),
"%qD was declared here", sect->named.decl);
}
else if (decl != NULL && DECL_P (decl))
error ("%+qD causes a section type conflict", decl);
else
error ("section type conflict");
/* Make sure we don't error about one section multiple times. */
sect->common.flags |= SECTION_OVERRIDE;
}
}
return sect;
}
/* Return true if the current compilation mode benefits from having
objects grouped into blocks. */
static bool
use_object_blocks_p (void)
{
return flag_section_anchors;
}
/* Return the object_block structure for section SECT. Create a new
structure if we haven't created one already. Return null if SECT
itself is null. Return also null for mergeable sections since
section anchors can't be used in mergeable sections anyway,
because the linker might move objects around, and using the
object blocks infrastructure in that case is both a waste and a
maintenance burden. */
static struct object_block *
get_block_for_section (section *sect)
{
struct object_block *block;
if (sect == NULL)
return NULL;
if (sect->common.flags & SECTION_MERGE)
return NULL;
object_block **slot
= object_block_htab->find_slot_with_hash (sect, hash_section (sect),
INSERT);
block = *slot;
if (block == NULL)
{
block = ggc_cleared_alloc<object_block> ();
block->sect = sect;
*slot = block;
}
return block;
}
/* Create a symbol with label LABEL and place it at byte offset
OFFSET in BLOCK. OFFSET can be negative if the symbol's offset
is not yet known. LABEL must be a garbage-collected string. */
static rtx
create_block_symbol (const char *label, struct object_block *block,
HOST_WIDE_INT offset)
{
rtx symbol;
unsigned int size;
/* Create the extended SYMBOL_REF. */
size = RTX_HDR_SIZE + sizeof (struct block_symbol);
symbol = (rtx) ggc_internal_alloc (size);
/* Initialize the normal SYMBOL_REF fields. */
memset (symbol, 0, size);
PUT_CODE (symbol, SYMBOL_REF);
PUT_MODE (symbol, Pmode);
XSTR (symbol, 0) = label;
SYMBOL_REF_FLAGS (symbol) = SYMBOL_FLAG_HAS_BLOCK_INFO;
/* Initialize the block_symbol stuff. */
SYMBOL_REF_BLOCK (symbol) = block;
SYMBOL_REF_BLOCK_OFFSET (symbol) = offset;
return symbol;
}
/* Return a section with a particular name and with whatever SECTION_*
flags section_type_flags deems appropriate. The name of the section
is taken from NAME if nonnull, otherwise it is taken from DECL's
DECL_SECTION_NAME. DECL is the decl associated with the section
(see the section comment for details) and RELOC is as for
section_type_flags. */
section *
get_named_section (tree decl, const char *name, int reloc)
{
unsigned int flags;
if (name == NULL)
{
gcc_assert (decl && DECL_P (decl) && DECL_SECTION_NAME (decl));
name = DECL_SECTION_NAME (decl);
}
flags = targetm.section_type_flags (decl, name, reloc);
return get_section (name, flags, decl);
}
/* Worker for resolve_unique_section. */
static bool
set_implicit_section (struct symtab_node *n, void *data ATTRIBUTE_UNUSED)
{
n->implicit_section = true;
return false;
}
/* If required, set DECL_SECTION_NAME to a unique name. */
void
resolve_unique_section (tree decl, int reloc ATTRIBUTE_UNUSED,
int flag_function_or_data_sections)
{
if (DECL_SECTION_NAME (decl) == NULL
&& targetm_common.have_named_sections
&& (flag_function_or_data_sections
|| lookup_attribute ("retain", DECL_ATTRIBUTES (decl))
|| DECL_COMDAT_GROUP (decl)))
{
targetm.asm_out.unique_section (decl, reloc);
if (DECL_SECTION_NAME (decl))
symtab_node::get (decl)->call_for_symbol_and_aliases
(set_implicit_section, NULL, true);
}
}
#ifdef BSS_SECTION_ASM_OP
#ifdef ASM_OUTPUT_ALIGNED_BSS
/* Utility function for targets to use in implementing
ASM_OUTPUT_ALIGNED_BSS.
??? It is believed that this function will work in most cases so such
support is localized here. */
static void
asm_output_aligned_bss (FILE *file, tree decl ATTRIBUTE_UNUSED,
const char *name, unsigned HOST_WIDE_INT size,
int align)
{
switch_to_section (bss_section);
ASM_OUTPUT_ALIGN (file, floor_log2 (align / BITS_PER_UNIT));
#ifdef ASM_DECLARE_OBJECT_NAME
last_assemble_variable_decl = decl;
ASM_DECLARE_OBJECT_NAME (file, name, decl);
#else
/* Standard thing is just output label for the object. */
ASM_OUTPUT_LABEL (file, name);
#endif /* ASM_DECLARE_OBJECT_NAME */
ASM_OUTPUT_SKIP (file, size ? size : 1);
}
#endif
#endif /* BSS_SECTION_ASM_OP */
#ifndef USE_SELECT_SECTION_FOR_FUNCTIONS
/* Return the hot section for function DECL. Return text_section for
null DECLs. */
static section *
hot_function_section (tree decl)
{
if (decl != NULL_TREE
&& DECL_SECTION_NAME (decl) != NULL
&& targetm_common.have_named_sections)
return get_named_section (decl, NULL, 0);
else
return text_section;
}
#endif
/* Return section for TEXT_SECTION_NAME if DECL or DECL_SECTION_NAME (DECL)
is NULL.
When DECL_SECTION_NAME is non-NULL and it is implicit section and
NAMED_SECTION_SUFFIX is non-NULL, then produce section called
concatenate the name with NAMED_SECTION_SUFFIX.
Otherwise produce "TEXT_SECTION_NAME.IMPLICIT_NAME". */
section *
get_named_text_section (tree decl,
const char *text_section_name,
const char *named_section_suffix)
{
if (decl && DECL_SECTION_NAME (decl))
{
if (named_section_suffix)
{
const char *dsn = DECL_SECTION_NAME (decl);
const char *stripped_name;
char *name, *buffer;
name = (char *) alloca (strlen (dsn) + 1);
memcpy (name, dsn,
strlen (dsn) + 1);
stripped_name = targetm.strip_name_encoding (name);
buffer = ACONCAT ((stripped_name, named_section_suffix, NULL));
return get_named_section (decl, buffer, 0);
}
else if (symtab_node::get (decl)->implicit_section)
{
const char *name;
/* Do not try to split gnu_linkonce functions. This gets somewhat
slipperly. */
if (DECL_COMDAT_GROUP (decl) && !HAVE_COMDAT_GROUP)
return NULL;
name = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
name = targetm.strip_name_encoding (name);
return get_named_section (decl, ACONCAT ((text_section_name, ".",
name, NULL)), 0);
}
else
return NULL;
}
return get_named_section (decl, text_section_name, 0);
}
/* Choose named function section based on its frequency. */
section *
default_function_section (tree decl, enum node_frequency freq,
bool startup, bool exit)
{
#if defined HAVE_LD_EH_GC_SECTIONS && defined HAVE_LD_EH_GC_SECTIONS_BUG
/* Old GNU linkers have buggy --gc-section support, which sometimes
results in .gcc_except_table* sections being garbage collected. */
if (decl
&& symtab_node::get (decl)->implicit_section)
return NULL;
#endif
if (!flag_reorder_functions
|| !targetm_common.have_named_sections)
return NULL;
/* Startup code should go to startup subsection unless it is
unlikely executed (this happens especially with function splitting
where we can split away unnecessary parts of static constructors. */
if (startup && freq != NODE_FREQUENCY_UNLIKELY_EXECUTED)
{
/* During LTO the tp_first_run profiling will naturally place all
initialization code first. Using separate section is counter-productive
because startup only code may call functions which are no longer
startup only. */
if (!in_lto_p
|| !cgraph_node::get (decl)->tp_first_run
|| !opt_for_fn (decl, flag_profile_reorder_functions))
return get_named_text_section (decl, ".text.startup", NULL);
else
return NULL;
}
/* Similarly for exit. */
if (exit && freq != NODE_FREQUENCY_UNLIKELY_EXECUTED)
return get_named_text_section (decl, ".text.exit", NULL);
/* Group cold functions together, similarly for hot code. */
switch (freq)
{
case NODE_FREQUENCY_UNLIKELY_EXECUTED:
return get_named_text_section (decl, ".text.unlikely", NULL);
case NODE_FREQUENCY_HOT:
return get_named_text_section (decl, ".text.hot", NULL);
/* FALLTHRU */
default:
return NULL;
}
}
/* Return the section for function DECL.
If DECL is NULL_TREE, return the text section. We can be passed
NULL_TREE under some circumstances by dbxout.cc at least.
If FORCE_COLD is true, return cold function section ignoring
the frequency info of cgraph_node. */
static section *
function_section_1 (tree decl, bool force_cold)
{
section *section = NULL;
enum node_frequency freq = NODE_FREQUENCY_NORMAL;
bool startup = false, exit = false;
if (decl)
{
struct cgraph_node *node = cgraph_node::get (decl);
if (node)
{
freq = node->frequency;
startup = node->only_called_at_startup;
exit = node->only_called_at_exit;
}
}
if (force_cold)
freq = NODE_FREQUENCY_UNLIKELY_EXECUTED;
#ifdef USE_SELECT_SECTION_FOR_FUNCTIONS
if (decl != NULL_TREE
&& DECL_SECTION_NAME (decl) != NULL)
{
if (targetm.asm_out.function_section)
section = targetm.asm_out.function_section (decl, freq,
startup, exit);
if (section)
return section;
return get_named_section (decl, NULL, 0);
}
else
return targetm.asm_out.select_section
(decl, freq == NODE_FREQUENCY_UNLIKELY_EXECUTED,
symtab_node::get (decl)->definition_alignment ());
#else
if (targetm.asm_out.function_section)
section = targetm.asm_out.function_section (decl, freq, startup, exit);
if (section)
return section;
return hot_function_section (decl);
#endif
}
/* Return the section for function DECL.
If DECL is NULL_TREE, return the text section. We can be passed
NULL_TREE under some circumstances by dbxout.cc at least. */
section *
function_section (tree decl)
{
/* Handle cases where function splitting code decides
to put function entry point into unlikely executed section
despite the fact that the function itself is not cold
(i.e. it is called rarely but contains a hot loop that is
better to live in hot subsection for the code locality). */
return function_section_1 (decl,
first_function_block_is_cold);
}
/* Return the section for the current function, take IN_COLD_SECTION_P
into account. */
section *
current_function_section (void)
{
return function_section_1 (current_function_decl, in_cold_section_p);
}
/* Tell assembler to switch to unlikely-to-be-executed text section. */
section *
unlikely_text_section (void)
{
return function_section_1 (current_function_decl, true);
}
/* When called within a function context, return true if the function
has been assigned a cold text section and if SECT is that section.
When called outside a function context, return true if SECT is the
default cold section. */
bool
unlikely_text_section_p (section *sect)
{
return sect == function_section_1 (current_function_decl, true);
}
/* Switch to the other function partition (if inside of hot section
into cold section, otherwise into the hot section). */
void
switch_to_other_text_partition (void)
{
in_cold_section_p = !in_cold_section_p;
switch_to_section (current_function_section ());
}
/* Return the read-only or relocated read-only data section
associated with function DECL. */
section *
default_function_rodata_section (tree decl, bool relocatable)
{
const char* sname;
unsigned int flags;
flags = 0;
if (relocatable)
{
sname = ".data.rel.ro.local";
flags = (SECTION_WRITE | SECTION_RELRO);
}
else
sname = ".rodata";
if (decl && DECL_SECTION_NAME (decl))
{
const char *name = DECL_SECTION_NAME (decl);
if (DECL_COMDAT_GROUP (decl) && HAVE_COMDAT_GROUP)
{
const char *dot;
size_t len;
char* rname;
dot = strchr (name + 1, '.');
if (!dot)
dot = name;
len = strlen (dot) + strlen (sname) + 1;
rname = (char *) alloca (len);
strcpy (rname, sname);
strcat (rname, dot);
return get_section (rname, (SECTION_LINKONCE | flags), decl);
}
/* For .gnu.linkonce.t.foo we want to use .gnu.linkonce.r.foo or
.gnu.linkonce.d.rel.ro.local.foo if the jump table is relocatable. */
else if (DECL_COMDAT_GROUP (decl)
&& startswith (name, ".gnu.linkonce.t."))
{
size_t len;
char *rname;
if (relocatable)
{
len = strlen (name) + strlen (".rel.ro.local") + 1;
rname = (char *) alloca (len);
strcpy (rname, ".gnu.linkonce.d.rel.ro.local");
strcat (rname, name + 15);
}
else
{
len = strlen (name) + 1;
rname = (char *) alloca (len);
memcpy (rname, name, len);
rname[14] = 'r';
}
return get_section (rname, (SECTION_LINKONCE | flags), decl);
}
/* For .text.foo we want to use .rodata.foo. */
else if (flag_function_sections && flag_data_sections
&& startswith (name, ".text."))
{
size_t len = strlen (name) + 1;
char *rname = (char *) alloca (len + strlen (sname) - 5);
memcpy (rname, sname, strlen (sname));
memcpy (rname + strlen (sname), name + 5, len - 5);
return get_section (rname, flags, decl);
}
}
if (relocatable)
return get_section (sname, flags, decl);
else
return readonly_data_section;
}
/* Return the read-only data section associated with function DECL
for targets where that section should be always the single
readonly data section. */
section *
default_no_function_rodata_section (tree, bool)
{
return readonly_data_section;
}
/* A subroutine of mergeable_string_section and mergeable_constant_section. */
static const char *
function_mergeable_rodata_prefix (void)
{
section *s = targetm.asm_out.function_rodata_section (current_function_decl,
false);
if (SECTION_STYLE (s) == SECTION_NAMED)
return s->named.name;
else
return targetm.asm_out.mergeable_rodata_prefix;
}
/* Return the section to use for string merging. */
static section *
mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
unsigned HOST_WIDE_INT align ATTRIBUTE_UNUSED,
unsigned int flags ATTRIBUTE_UNUSED)
{
HOST_WIDE_INT len;
if (HAVE_GAS_SHF_MERGE && flag_merge_constants
&& TREE_CODE (decl) == STRING_CST
&& TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
&& align <= 256
&& (len = int_size_in_bytes (TREE_TYPE (decl))) > 0
&& TREE_STRING_LENGTH (decl) == len)
{
scalar_int_mode mode;
unsigned int modesize;
const char *str;
HOST_WIDE_INT i;
int j, unit;
const char *prefix = function_mergeable_rodata_prefix ();
char *name = (char *) alloca (strlen (prefix) + 30);
mode = SCALAR_INT_TYPE_MODE (TREE_TYPE (TREE_TYPE (decl)));
modesize = GET_MODE_BITSIZE (mode);
if (modesize >= 8 && modesize <= 256
&& (modesize & (modesize - 1)) == 0)
{
if (align < modesize)
align = modesize;
str = TREE_STRING_POINTER (decl);
unit = GET_MODE_SIZE (mode);
/* Check for embedded NUL characters. */
for (i = 0; i < len; i += unit)
{
for (j = 0; j < unit; j++)
if (str[i + j] != '\0')
break;
if (j == unit)
break;
}
if (i == len - unit || (unit == 1 && i == len))
{
sprintf (name, "%s.str%d.%d", prefix,
modesize / 8, (int) (align / 8));
flags |= (modesize / 8) | SECTION_MERGE | SECTION_STRINGS;
return get_section (name, flags, NULL);
}
}
}
return readonly_data_section;
}
/* Return the section to use for constant merging. */
section *
mergeable_constant_section (machine_mode mode ATTRIBUTE_UNUSED,
unsigned HOST_WIDE_INT align ATTRIBUTE_UNUSED,
unsigned int flags ATTRIBUTE_UNUSED)
{
if (HAVE_GAS_SHF_MERGE && flag_merge_constants
&& mode != VOIDmode
&& mode != BLKmode
&& known_le (GET_MODE_BITSIZE (mode), align)
&& align >= 8
&& align <= 256
&& (align & (align - 1)) == 0)
{
const char *prefix = function_mergeable_rodata_prefix ();
char *name = (char *) alloca (strlen (prefix) + 30);
sprintf (name, "%s.cst%d", prefix, (int) (align / 8));
flags |= (align / 8) | SECTION_MERGE;
return get_section (name, flags, NULL);
}
return readonly_data_section;
}
/* Given NAME, a putative register name, discard any customary prefixes. */
static const char *
strip_reg_name (const char *name)
{
#ifdef REGISTER_PREFIX
if (!strncmp (name, REGISTER_PREFIX, strlen (REGISTER_PREFIX)))
name += strlen (REGISTER_PREFIX);
#endif
if (name[0] == '%' || name[0] == '#')
name++;
return name;
}
/* The user has asked for a DECL to have a particular name. Set (or
change) it in such a way that we don't prefix an underscore to
it. */
void
set_user_assembler_name (tree decl, const char *name)
{
char *starred = (char *) alloca (strlen (name) + 2);
starred[0] = '*';
strcpy (starred + 1, name);
symtab->change_decl_assembler_name (decl, get_identifier (starred));
SET_DECL_RTL (decl, NULL_RTX);
}
/* Decode an `asm' spec for a declaration as a register name.
Return the register number, or -1 if nothing specified,
or -2 if the ASMSPEC is not `cc' or `memory' and is not recognized,
or -3 if ASMSPEC is `cc' and is not recognized,
or -4 if ASMSPEC is `memory' and is not recognized.
Accept an exact spelling or a decimal number.
Prefixes such as % are optional. */
int
decode_reg_name_and_count (const char *asmspec, int *pnregs)
{
/* Presume just one register is clobbered. */
*pnregs = 1;
if (asmspec != 0)
{
int i;
/* Get rid of confusing prefixes. */
asmspec = strip_reg_name (asmspec);
/* Allow a decimal number as a "register name". */
for (i = strlen (asmspec) - 1; i >= 0; i--)
if (! ISDIGIT (asmspec[i]))
break;
if (asmspec[0] != 0 && i < 0)
{
i = atoi (asmspec);
if (i < FIRST_PSEUDO_REGISTER && i >= 0 && reg_names[i][0])
return i;
else
return -2;
}
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)