GCC Middle and Back End API Reference
explow.cc File Reference
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "target.h"
#include "function.h"
#include "rtl.h"
#include "tree.h"
#include "memmodel.h"
#include "tm_p.h"
#include "optabs.h"
#include "expmed.h"
#include "profile-count.h"
#include "emit-rtl.h"
#include "recog.h"
#include "diagnostic-core.h"
#include "stor-layout.h"
#include "langhooks.h"
#include "except.h"
#include "dojump.h"
#include "explow.h"
#include "expr.h"
#include "stringpool.h"
#include "common/common-target.h"
#include "output.h"
#include "gt-explow.h"
Include dependency graph for explow.cc:

Macros

#define PROBE_INTERVAL   (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
 
#define STACK_GROW_OP   PLUS
 
#define STACK_GROW_OPTAB   add_optab
 
#define STACK_GROW_OFF(off)   (off)
 

Functions

static rtx break_out_memory_refs (rtx)
 
HOST_WIDE_INT trunc_int_for_mode (HOST_WIDE_INT c, machine_mode mode)
 
poly_int64 trunc_int_for_mode (poly_int64 x, machine_mode mode)
 
rtx plus_constant (machine_mode mode, rtx x, poly_int64 c, bool inplace)
 
rtx eliminate_constant_term (rtx x, rtx *constptr)
 
rtx convert_memory_address_addr_space_1 (scalar_int_mode to_mode, rtx x, addr_space_t as, bool in_const, bool no_emit)
 
rtx convert_memory_address_addr_space (scalar_int_mode to_mode, rtx x, addr_space_t as)
 
rtx memory_address_addr_space (machine_mode mode, rtx x, addr_space_t as)
 
rtx validize_mem (rtx ref)
 
rtx use_anchored_address (rtx x)
 
rtx copy_to_reg (rtx x)
 
rtx copy_addr_to_reg (rtx x)
 
rtx copy_to_mode_reg (machine_mode mode, rtx x)
 
rtx force_reg (machine_mode mode, rtx x)
 
rtx force_subreg (machine_mode outermode, rtx op, machine_mode innermode, poly_uint64 byte)
 
rtx force_lowpart_subreg (machine_mode outermode, rtx op, machine_mode innermode)
 
rtx force_highpart_subreg (machine_mode outermode, rtx op, machine_mode innermode)
 
rtx force_not_mem (rtx x)
 
rtx copy_to_suggested_reg (rtx x, rtx target, machine_mode mode)
 
machine_mode promote_function_mode (const_tree type, machine_mode mode, int *punsignedp, const_tree funtype, int for_return)
 
machine_mode promote_mode (const_tree type, machine_mode mode, int *punsignedp)
 
machine_mode promote_decl_mode (const_tree decl, int *punsignedp)
 
machine_mode promote_ssa_mode (const_tree name, int *punsignedp)
 
static void adjust_stack_1 (rtx adjust, bool anti_p)
 
void adjust_stack (rtx adjust)
 
void anti_adjust_stack (rtx adjust)
 
static rtx round_push (rtx size)
 
void emit_stack_save (enum save_level save_level, rtx *psave)
 
void emit_stack_restore (enum save_level save_level, rtx sa)
 
void update_nonlocal_goto_save_area (void)
 
void record_new_stack_level (void)
 
rtx align_dynamic_address (rtx target, unsigned required_align)
 
void get_dynamic_stack_size (rtx *psize, unsigned size_align, unsigned required_align, HOST_WIDE_INT *pstack_usage_size)
 
HOST_WIDE_INT get_stack_check_protect (void)
 
rtx allocate_dynamic_stack_space (rtx size, unsigned size_align, unsigned required_align, HOST_WIDE_INT max_size, bool cannot_accumulate)
 
rtx get_dynamic_stack_base (poly_int64 offset, unsigned required_align, rtx base)
 
void set_stack_check_libfunc (const char *libfunc_name)
 
void emit_stack_probe (rtx address)
 
void probe_stack_range (HOST_WIDE_INT first, rtx size)
 
void compute_stack_clash_protection_loop_data (rtx *rounded_size, rtx *last_addr, rtx *residual, HOST_WIDE_INT *probe_interval, rtx size)
 
void emit_stack_clash_protection_probe_loop_start (rtx *loop_lab, rtx *end_lab, rtx last_addr, bool rotated)
 
void emit_stack_clash_protection_probe_loop_end (rtx loop_lab, rtx end_loop, rtx last_addr, bool rotated)
 
void anti_adjust_stack_and_probe_stack_clash (rtx size)
 
void anti_adjust_stack_and_probe (rtx size, bool adjust_back)
 
rtx hard_function_value (const_tree valtype, const_tree func, const_tree fntype, int outgoing)
 
rtx hard_libcall_value (machine_mode mode, rtx fun)
 
int rtx_to_tree_code (enum rtx_code code)
 

Variables

static bool suppress_reg_args_size
 
static rtx stack_check_libfunc
 

Macro Definition Documentation

◆ PROBE_INTERVAL

#define PROBE_INTERVAL   (1 << STACK_CHECK_PROBE_INTERVAL_EXP)
Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
FIRST is a constant and size is a Pmode RTX.  These are offsets from
the current stack pointer.  STACK_GROWS_DOWNWARD says whether to add
or subtract them from the stack pointer.   

Referenced by anti_adjust_stack_and_probe(), and probe_stack_range().

◆ STACK_GROW_OFF

#define STACK_GROW_OFF ( off)    (off)

Referenced by probe_stack_range().

◆ STACK_GROW_OP

◆ STACK_GROW_OPTAB

#define STACK_GROW_OPTAB   add_optab

Referenced by probe_stack_range().

Function Documentation

◆ adjust_stack()

void adjust_stack ( rtx adjust)
Adjust the stack pointer by ADJUST (an rtx for a number of bytes).
This pops when ADJUST is positive.  ADJUST need not be constant.   

References adjust_stack_1(), const0_rtx, poly_int_rtx_p(), and stack_pointer_delta.

Referenced by anti_adjust_stack_and_probe(), do_pending_stack_adjust(), and emit_call_1().

◆ adjust_stack_1()

static void adjust_stack_1 ( rtx adjust,
bool anti_p )
static

◆ align_dynamic_address()

rtx align_dynamic_address ( rtx target,
unsigned required_align )
Return an rtx doing runtime alignment to REQUIRED_ALIGN on TARGET.   

References expand_binop(), expand_divmod(), expand_mult(), gen_int_mode(), NULL_RTX, and OPTAB_LIB_WIDEN.

Referenced by allocate_dynamic_stack_space(), assign_parm_setup_block(), and get_dynamic_stack_base().

◆ allocate_dynamic_stack_space()

rtx allocate_dynamic_stack_space ( rtx size,
unsigned size_align,
unsigned required_align,
HOST_WIDE_INT max_size,
bool cannot_accumulate )
Return an rtx representing the address of an area of memory dynamically
pushed on the stack.

Any required stack pointer alignment is preserved.

SIZE is an rtx representing the size of the area.

SIZE_ALIGN is the alignment (in bits) that we know SIZE has.  This
parameter may be zero.  If so, a proper value will be extracted
from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.

REQUIRED_ALIGN is the alignment (in bits) required for the region
of memory.

MAX_SIZE is an upper bound for SIZE, if SIZE is not constant, or -1 if
no such upper bound is known.

If CANNOT_ACCUMULATE is set to TRUE, the caller guarantees that the
stack space allocated by the generated code cannot be added with itself
in the course of the execution of the function.  It is always safe to
pass FALSE here and the following criterion is sufficient in order to
pass TRUE: every path in the CFG that starts at the allocation point and
loops to it executes the associated deallocation code.   

References align_dynamic_address(), anti_adjust_stack(), anti_adjust_stack_and_probe(), anti_adjust_stack_and_probe_stack_clash(), cfun, const0_rtx, CONST_INT_P, create_convert_operand_to(), create_fixed_operand(), crtl, current_function_dynamic_stack_size, current_function_has_unbounded_dynamic_stack_size, do_pending_stack_adjust(), emit_barrier(), emit_cmp_and_jump_insns(), emit_insn(), emit_jump(), emit_label(), emit_library_call_value(), emit_move_insn(), error(), expand_binop(), expand_insn(), find_reg_equal_equiv_note(), force_operand(), gcc_assert, gen_int_mode(), gen_label_rtx(), gen_reg_rtx(), GENERIC_STACK_CHECK, get_dynamic_stack_size(), get_last_insn(), get_stack_check_protect(), get_stack_dynamic_offset(), init_one_libfunc(), INTVAL, LCT_NORMAL, MALLOC_ABI_ALIGNMENT, mark_reg_pointer(), NULL, NULL_RTX, OPTAB_LIB_WIDEN, OPTAB_WIDEN, plus_constant(), PREFERRED_STACK_BOUNDARY, probe_stack_range(), record_new_stack_level(), REG_P, rtx_equal_p(), SET_DEST, SET_SRC, single_set(), STACK_GROWS_DOWNWARD, stack_limit_rtx, stack_pointer_delta, stack_pointer_rtx, STATIC_BUILTIN_STACK_CHECK, suppress_reg_args_size, expand_operand::target, targetm, virtual_stack_dynamic_rtx, virtuals_instantiated, and XEXP.

Referenced by expand_builtin_alloca(), expand_builtin_apply(), expand_call(), and initialize_argument_information().

◆ anti_adjust_stack()

void anti_adjust_stack ( rtx adjust)
Adjust the stack pointer by minus ADJUST (an rtx for a number of bytes).
This pushes when ADJUST is positive.  ADJUST need not be constant.   

References adjust_stack_1(), const0_rtx, poly_int_rtx_p(), and stack_pointer_delta.

Referenced by allocate_dynamic_stack_space(), anti_adjust_stack_and_probe(), anti_adjust_stack_and_probe_stack_clash(), emit_call_1(), emit_library_call_value_1(), emit_push_insn(), expand_call(), push_block(), and store_one_arg().

◆ anti_adjust_stack_and_probe()

void anti_adjust_stack_and_probe ( rtx size,
bool adjust_back )
Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
while probing it.  This pushes when SIZE is positive.  SIZE need not
be constant.  If ADJUST_BACK is true, adjust back the stack pointer
by plus SIZE at the end.   

References adjust_stack(), anti_adjust_stack(), const0_rtx, CONST_INT_P, convert_to_mode(), emit_cmp_and_jump_insns(), emit_jump(), emit_label(), emit_stack_probe(), force_operand(), GEN_INT, gen_int_mode(), gen_label_rtx(), GET_CODE, GET_MODE, i, INTVAL, NULL_RTX, plus_constant(), PROBE_INTERVAL, simplify_gen_binary(), STACK_GROW_OP, and stack_pointer_rtx.

Referenced by allocate_dynamic_stack_space(), and expand_function_end().

◆ anti_adjust_stack_and_probe_stack_clash()

void anti_adjust_stack_and_probe_stack_clash ( rtx size)
Adjust the stack pointer by minus SIZE (an rtx for a number of bytes)
while probing it.  This pushes when SIZE is positive.  SIZE need not
be constant.

This is subtly different than anti_adjust_stack_and_probe to try and
prevent stack-clash attacks

  1. It must assume no knowledge of the probing state, any allocation
     must probe.

     Consider the case of a 1 byte alloca in a loop.  If the sum of the
     allocations is large, then this could be used to jump the guard if
     probes were not emitted.

  2. It never skips probes, whereas anti_adjust_stack_and_probe will
     skip the probe on the first PROBE_INTERVAL on the assumption it
     was already done in the prologue and in previous allocations.

  3. It only allocates and probes SIZE bytes, it does not need to
     allocate/probe beyond that because this probing style does not
     guarantee signal handling capability if the guard is hit.   

References anti_adjust_stack(), compute_stack_clash_protection_loop_data(), CONST0_RTX, CONST_INT_P, convert_to_mode(), emit_cmp_and_jump_insns(), emit_insn(), emit_label(), emit_stack_clash_protection_probe_loop_end(), emit_stack_clash_protection_probe_loop_start(), emit_stack_probe(), gcc_assert, gen_blockage(), GEN_INT, gen_label_rtx(), gen_rtx_CONST_INT(), GET_MODE, GET_MODE_SIZE(), i, INTVAL, NULL_RTX, plus_constant(), rotate_loop(), stack_pointer_rtx, targetm, and word_mode.

Referenced by allocate_dynamic_stack_space().

◆ break_out_memory_refs()

static rtx break_out_memory_refs ( rtx x)
static
Subroutines for manipulating rtx's in semantically interesting ways.
   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/>.   
Return a copy of X in which all memory references
and all constants that involve symbol refs
have been replaced with new temporary registers.
Also emit code to load the memory locations and constants
into those registers.

If X contains no such constants or memory references,
X itself (not a copy) is returned.

If a constant is found in the address that is not a legitimate constant
in an insn, it is left alone in the hope that it might be valid in the
address.

X may contain no arithmetic except addition, subtraction and multiplication.
Values returned by expand_expr with 1 for sum_ok fit this constraint.   

References break_out_memory_refs(), CONSTANT_ADDRESS_P, CONSTANT_P, force_reg(), GET_CODE, GET_MODE, MEM_P, simplify_gen_binary(), and XEXP.

Referenced by break_out_memory_refs(), and memory_address_addr_space().

◆ compute_stack_clash_protection_loop_data()

void compute_stack_clash_protection_loop_data ( rtx * rounded_size,
rtx * last_addr,
rtx * residual,
HOST_WIDE_INT * probe_interval,
rtx size )
Compute parameters for stack clash probing a dynamic stack
allocation of SIZE bytes.

We compute ROUNDED_SIZE, LAST_ADDR, RESIDUAL and PROBE_INTERVAL.

Additionally we conditionally dump the type of probing that will
be needed given the values computed.   

References CONST0_RTX, CONST_INT_P, dump_file, force_operand(), GEN_INT, INTVAL, NULL_RTX, simplify_gen_binary(), STACK_GROW_OP, and stack_pointer_rtx.

Referenced by anti_adjust_stack_and_probe_stack_clash().

◆ convert_memory_address_addr_space()

rtx convert_memory_address_addr_space ( scalar_int_mode to_mode,
rtx x,
addr_space_t as )
Given X, a memory address in address space AS' pointer mode, convert it to
an address in the address space's address mode, or vice versa (TO_MODE says
which way).  We take advantage of the fact that pointers are not allowed to
overflow by commuting arithmetic operations over conversions so that address
arithmetic insns can be used.   

References convert_memory_address_addr_space_1().

Referenced by expand_assignment(), expand_expr_addr_expr(), expand_expr_addr_expr_1(), make_tree(), and memory_address_addr_space().

◆ convert_memory_address_addr_space_1()

rtx convert_memory_address_addr_space_1 ( scalar_int_mode to_mode,
rtx x,
addr_space_t as,
bool in_const,
bool no_emit )
Given X, a memory address in address space AS' pointer mode, convert it to
an address in the address space's address mode, or vice versa (TO_MODE says
which way).  We take advantage of the fact that pointers are not allowed to
overflow by commuting arithmetic operations over conversions so that address
arithmetic insns can be used. IN_CONST is true if this conversion is inside
a CONST. NO_EMIT is true if no insns should be emitted, and instead
it should return NULL if it can't be simplified without emitting insns.   

References CASE_CONST_SCALAR_INT, CONST_INT_P, convert_memory_address_addr_space_1(), convert_modes(), gcc_assert, gen_rtvec(), GET_CODE, get_last_insn(), GET_MODE, GET_MODE_SIZE(), i, label_ref_label(), LABEL_REF_NONLOCAL_P, last, NULL_RTX, PUT_MODE(), REG_POINTER, RTVEC_ELT, shallow_copy_rtx(), simplify_unary_operation(), SUBREG_PROMOTED_VAR_P, SUBREG_REG, targetm, XEXP, XINT, XVECEXP, and XVECLEN.

Referenced by convert_memory_address_addr_space(), convert_memory_address_addr_space_1(), and simplify_context::simplify_unary_operation_1().

◆ copy_addr_to_reg()

◆ copy_to_mode_reg()

◆ copy_to_reg()

◆ copy_to_suggested_reg()

rtx copy_to_suggested_reg ( rtx x,
rtx target,
machine_mode mode )
Copy X to TARGET (if it's nonzero and a reg)
or to a new temp reg and return that reg.
MODE is the mode to use for X in case it is a constant.   

References emit_move_insn(), gen_reg_rtx(), and REG_P.

◆ eliminate_constant_term()

rtx eliminate_constant_term ( rtx x,
rtx * constptr )
If X is a sum, return a new sum like X but lacking any constant terms.
Add all the removed constant terms into *CONSTPTR.
X itself is not altered.  The result != X if and only if
it is not isomorphic to X.   

References const0_rtx, CONST_INT_P, eliminate_constant_term(), GET_CODE, GET_MODE, simplify_binary_operation(), and XEXP.

Referenced by eliminate_constant_term(), and memory_address_addr_space().

◆ emit_stack_clash_protection_probe_loop_end()

void emit_stack_clash_protection_probe_loop_end ( rtx loop_lab,
rtx end_loop,
rtx last_addr,
bool rotated )
Emit the end of a stack clash probing loop.

This consists of just the jump back to LOOP_LAB and
emitting END_LOOP after the loop.   

References emit_cmp_and_jump_insns(), emit_jump(), emit_label(), NULL_RTX, and stack_pointer_rtx.

Referenced by anti_adjust_stack_and_probe_stack_clash().

◆ emit_stack_clash_protection_probe_loop_start()

void emit_stack_clash_protection_probe_loop_start ( rtx * loop_lab,
rtx * end_lab,
rtx last_addr,
bool rotated )
Emit the start of an allocate/probe loop for stack
clash protection.

LOOP_LAB and END_LAB are returned for use when we emit the
end of the loop.

LAST addr is the value for SP which stops the loop.   

References emit_cmp_and_jump_insns(), emit_label(), gen_label_rtx(), NULL_RTX, and stack_pointer_rtx.

Referenced by anti_adjust_stack_and_probe_stack_clash().

◆ emit_stack_probe()

◆ emit_stack_restore()

void emit_stack_restore ( enum save_level save_level ,
rtx sa )
Restore the stack pointer for the purpose in SAVE_LEVEL.  SA is the save
area made by emit_stack_save.  If it is zero, we have nothing to do.   

References crtl, discard_pending_stack_adjust(), emit_clobber(), emit_insn(), gen_move_insn(), gen_rtx_MEM(), SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL, stack_pointer_rtx, SUPPORTS_STACK_ALIGNMENT, targetm, and validize_mem().

Referenced by expand_builtin_apply(), expand_builtin_longjmp(), expand_builtin_nonlocal_goto(), expand_call(), expand_function_end(), and expand_stack_restore().

◆ emit_stack_save()

void emit_stack_save ( enum save_level save_level ,
rtx * psave )
Save the stack pointer for the purpose in SAVE_LEVEL.  PSAVE is a pointer
to a previously-created save area.  If no save area has been allocated,
this function will allocate one.  If a save area is specified, it
must be of the proper mode.   

References assign_stack_local(), do_pending_stack_adjust(), emit_insn(), gen_move_insn(), gen_reg_rtx(), GET_MODE_SIZE(), SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL, stack_pointer_rtx, targetm, and validize_mem().

Referenced by expand_builtin_apply(), expand_builtin_setjmp_setup(), expand_builtin_update_setjmp_buf(), expand_call(), expand_function_end(), expand_stack_save(), initialize_argument_information(), and update_nonlocal_goto_save_area().

◆ force_highpart_subreg()

rtx force_highpart_subreg ( machine_mode outermode,
rtx op,
machine_mode innermode )
Try to return an rvalue expression for the OUTERMODE highpart of OP,
which has mode INNERMODE.  Allow OP to be forced into a new register
if necessary.

Return null on failure.   

References force_subreg(), and subreg_highpart_offset().

Referenced by emit_store_flag_1(), and expand_builtin_issignaling().

◆ force_lowpart_subreg()

rtx force_lowpart_subreg ( machine_mode outermode,
rtx op,
machine_mode innermode )
Try to return an rvalue expression for the OUTERMODE lowpart of OP,
which has mode INNERMODE.  Allow OP to be forced into a new register
if necessary.

Return null on failure.   

References force_subreg(), and subreg_lowpart_offset().

Referenced by convert_mode_scalar(), expand_absneg_bit(), expand_builtin_issignaling(), expand_copysign_bit(), expand_doubleword_mod(), and expand_expr_real_2().

◆ force_not_mem()

rtx force_not_mem ( rtx x)
If X is a memory ref, copy its contents to a new temp reg and return
that reg.  Otherwise, return X.   

References emit_move_insn(), gen_reg_rtx(), GET_MODE, MEM_P, MEM_POINTER, and REG_POINTER.

Referenced by expand_assignment(), expand_return(), and prepare_call_address().

◆ force_reg()

rtx force_reg ( machine_mode mode,
rtx x )
Load X into a register if it is not already one.
Use mode MODE for the register.
X should be valid for mode MODE, but it may be a constant which
is valid for all integer modes; that's why caller must specify MODE.

The caller must not alter the value in the register we return,
since we mark it as a "constant" register.   

References CONST_INT_P, CONSTANT_P, ctz_hwi(), DECL_ALIGN, DECL_P, emit_move_insn(), force_operand(), gen_reg_rtx(), general_operand(), GET_CODE, get_last_insn(), INTVAL, mark_reg_pointer(), MEM_P, MEM_POINTER, MIN, NULL_RTX, REG_P, rtx_equal_p(), SET_DEST, SET_SRC, set_unique_reg_note(), single_set(), SYMBOL_REF_DECL, and XEXP.

Referenced by asan_clear_shadow(), assign_parm_setup_block(), assign_parm_setup_stack(), avoid_expensive_constant(), break_out_memory_refs(), builtin_memset_gen_str(), compress_float_constant(), convert_extracted_bit_field(), convert_float_to_wider_int(), convert_mode_scalar(), convert_wider_int_to_float(), emit_cmp_and_jump_insns(), emit_conditional_move(), emit_group_load_1(), emit_group_load_into_temps(), emit_library_call_value_1(), expand_asm_stmt(), expand_binop(), expand_builtin_frob_return_addr(), expand_builtin_longjmp(), expand_builtin_memset_args(), expand_builtin_setjmp_setup(), expand_builtin_signbit(), expand_builtin_stack_address(), expand_builtin_strub_leave(), expand_builtin_strub_update(), expand_call(), expand_divmod(), expand_doubleword_clz_ctz_ffs(), expand_doubleword_mult(), expand_expr_real_1(), expand_expr_real_2(), expand_ifn_atomic_compare_exchange_into_call(), expand_movstr(), expand_mul_overflow(), expand_mult(), expand_mult_const(), expand_sdiv_pow2(), expand_shift_1(), expand_smod_pow2(), expand_vec_perm_1(), expand_vec_perm_const(), extract_bit_field_1(), extract_fixed_bit_field_1(), extract_low_bits(), force_operand(), force_reload_address(), gen_lowpart_general(), hwasan_frame_base(), instantiate_virtual_regs_in_insn(), memory_address_addr_space(), offset_address(), operand_subword_force(), precompute_register_parameters(), prepare_call_address(), prepare_cmp_insn(), resolve_shift_zext(), sjlj_emit_dispatch_table(), store_bit_field_using_insv(), store_constructor(), store_fixed_bit_field_1(), store_split_bit_field(), try_store_by_multiple_pieces(), use_anchored_address(), and widen_operand().

◆ force_subreg()

rtx force_subreg ( machine_mode outermode,
rtx op,
machine_mode innermode,
poly_uint64 byte )

◆ get_dynamic_stack_base()

rtx get_dynamic_stack_base ( poly_int64 offset,
unsigned required_align,
rtx base )
Return an rtx representing the address of an area of memory already
statically pushed onto the stack in the virtual stack vars area.  (It is
assumed that the area is allocated in the function prologue.)

Any required stack pointer alignment is preserved.

OFFSET is the offset of the area into the virtual stack vars area.

REQUIRED_ALIGN is the alignment (in bits) required for the region
of memory.

BASE is the rtx of the base of this virtual stack vars area.
The only time this is not `virtual_stack_vars_rtx` is when tagging pointers
on the stack.   

References align_dynamic_address(), crtl, emit_move_insn(), expand_binop(), gen_int_mode(), gen_reg_rtx(), mark_reg_pointer(), NULL_RTX, offset, OPTAB_LIB_WIDEN, PREFERRED_STACK_BOUNDARY, and expand_operand::target.

Referenced by expand_stack_vars().

◆ get_dynamic_stack_size()

void get_dynamic_stack_size ( rtx * psize,
unsigned size_align,
unsigned required_align,
HOST_WIDE_INT * pstack_usage_size )
Return an rtx through *PSIZE, representing the size of an area of memory to
be dynamically pushed on the stack.

*PSIZE is an rtx representing the size of the area.

SIZE_ALIGN is the alignment (in bits) that we know SIZE has.  This
parameter may be zero.  If so, a proper value will be extracted
from SIZE if it is constant, otherwise BITS_PER_UNIT will be assumed.

REQUIRED_ALIGN is the alignment (in bits) required for the region
of memory.

If PSTACK_USAGE_SIZE is not NULL it points to a value that is increased for
the additional size returned.   

References CONST_INT_P, convert_to_mode(), crtl, force_operand(), GET_MODE, HOST_BITS_PER_INT, INTVAL, MAX_SUPPORTED_STACK_ALIGNMENT, NULL_RTX, plus_constant(), PREFERRED_STACK_BOUNDARY, REGNO_POINTER_ALIGN, round_push(), UINT_MAX, and VIRTUAL_STACK_DYNAMIC_REGNUM.

Referenced by allocate_dynamic_stack_space(), assign_parm_setup_block(), and expand_stack_vars().

◆ get_stack_check_protect()

HOST_WIDE_INT get_stack_check_protect ( void )
Return the number of bytes to "protect" on the stack for -fstack-check.

"protect" in the context of -fstack-check means how many bytes we need
to always ensure are available on the stack; as a consequence, this is
also how many bytes are first skipped when probing the stack.

On some targets we want to reuse the -fstack-check prologue support
to give a degree of protection against stack clashing style attacks.

In that scenario we do not want to skip bytes before probing as that
would render the stack clash protections useless.

So we never use STACK_CHECK_PROTECT directly.  Instead we indirectly
use it through this helper, which allows to provide different values
for -fstack-check and -fstack-clash-protection.   

Referenced by allocate_dynamic_stack_space().

◆ hard_function_value()

rtx hard_function_value ( const_tree valtype,
const_tree func,
const_tree fntype,
int outgoing )
Return an rtx representing the register or memory location
in which a scalar value of data type VALTYPE
was returned by a function call to function FUNC.
FUNC is a FUNCTION_DECL, FNTYPE a FUNCTION_TYPE node if the precise
function is known, otherwise 0.
OUTGOING is 1 if on a machine with register windows this function
should return the register in which the function will put its result
and 0 otherwise.   

References arg_int_size_in_bytes(), FOR_EACH_MODE_IN_CLASS, GET_MODE, GET_MODE_SIZE(), PUT_MODE(), REG_P, opt_mode< T >::require(), and targetm.

Referenced by aggregate_value_p(), emit_library_call_value_1(), expand_call(), expand_function_start(), and vectorizable_store().

◆ hard_libcall_value()

rtx hard_libcall_value ( machine_mode mode,
rtx fun )
Return an rtx representing the register or memory location
in which a scalar value of mode MODE was returned by a library call.   

References expand_operand::mode, and targetm.

Referenced by emit_library_call_value_1(), and expand_unop().

◆ memory_address_addr_space()

rtx memory_address_addr_space ( machine_mode mode,
rtx x,
addr_space_t as )
Return something equivalent to X but valid as a memory address for something
of mode MODE in the named address space AS.  When X is not itself valid,
this works by copying X or subexpressions of it into registers.   

References break_out_memory_refs(), const0_rtx, CONST_INT_P, CONSTANT_ADDRESS_P, CONSTANT_P, convert_memory_address_addr_space(), copy_to_reg(), cse_not_expected, eliminate_constant_term(), force_operand(), force_reg(), gcc_assert, GET_CODE, GET_MODE, mark_reg_pointer(), memory_address_addr_space_p(), NULL_RTX, REG_P, targetm, update_temp_slot_address(), XEXP, and y.

Referenced by change_address_1(), and expand_expr_real_1().

◆ plus_constant()

rtx plus_constant ( machine_mode mode,
rtx x,
poly_int64 c,
bool inplace )
Return an rtx for the sum of X and the integer C, given that X has
mode MODE.  INPLACE is true if X can be modified inplace or false
if it must be treated as immutable.   

References wi::add(), CASE_CONST_SCALAR_INT, const0_rtx, CONST_POLY_INT_P, const_poly_int_value(), CONSTANT_P, CONSTANT_POOL_ADDRESS_P, copy_rtx(), find_constant_term_loc(), force_const_mem(), gcc_assert, gen_int_mode(), gen_lowpart, GET_CODE, GET_MODE, GET_MODE_INNER, get_pool_constant(), get_pool_mode(), immed_wide_int_const(), known_eq, memory_address_p, plus_constant(), RTX_CODE, shared_const_p(), XEXP, and y.

Referenced by addr_side_effect_eval(), adjust_address_1(), adjust_mems(), allocate_dynamic_stack_space(), anti_adjust_stack_and_probe(), anti_adjust_stack_and_probe_stack_clash(), asan_clear_shadow(), asan_emit_stack_protection(), assign_stack_local_1(), autoinc_split(), check_mem_read_rtx(), combine_simplify_rtx(), compute_argument_addresses(), compute_cfa_pointer(), cselib_record_sp_cfa_base_equiv(), cselib_reset_table(), cselib_subst_to_values(), pieces_addr::decide_autoinc(), default_memtag_add_tag(), drop_writeback(), eliminate_regs_1(), eliminate_regs_in_insn(), eliminate_regs_in_insn(), emit_library_call_value_1(), emit_move_resolve_push(), emit_push_insn(), equiv_address_substitution(), expand_builtin_adjust_descriptor(), expand_builtin_apply(), expand_builtin_apply_args_1(), expand_builtin_extract_return_addr(), expand_builtin_frob_return_addr(), expand_builtin_longjmp(), expand_builtin_nonlocal_goto(), expand_builtin_return_addr(), expand_builtin_setjmp_setup(), expand_builtin_stack_address(), expand_builtin_stpcpy_1(), expand_builtin_strub_leave(), expand_builtin_strub_update(), expand_builtin_update_setjmp_buf(), expand_call(), expand_debug_expr(), expand_divmod(), expand_expr_addr_expr_1(), expand_expr_real_2(), expand_movstr(), expand_one_stack_var_at(), extract_writebacks(), find_reg_offset_for_const(), find_reloads_address(), fixup_debug_use(), fold_rtx(), force_int_to_mode(), form_sum(), form_sum(), pair_fusion_bb_info::fuse_pair(), get_addr(), get_dynamic_stack_size(), hwasan_emit_prologue(), hwasan_get_frame_extent(), init_alias_analysis(), init_reload(), insert_const_anchor(), instantiate_virtual_regs_in_rtx(), internal_arg_pointer_based_exp(), lra_eliminate_regs_1(), memory_load_overlap(), offsettable_address_addr_space_p(), plus_constant(), prepare_call_address(), prepare_call_arguments(), prepare_cmp_insn(), probe_stack_range(), push_block(), record_store(), round_push(), rtl_for_decl_location(), simplify_context::simplify_binary_operation_1(), simplify_context::simplify_plus_minus(), simplify_context::simplify_unary_operation_1(), sjlj_emit_function_enter(), sjlj_mark_call_sites(), store_expr(), try_apply_stack_adjustment(), try_store_by_multiple_pieces(), use_anchored_address(), use_related_value(), vt_add_function_parameter(), vt_canonicalize_addr(), and vt_initialize().

◆ probe_stack_range()

void probe_stack_range ( HOST_WIDE_INT first,
rtx size )
Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
FIRST is a constant and size is a Pmode RTX.  These are offsets from
the current stack pointer.  STACK_GROWS_DOWNWARD says whether to add
or subtract them from the stack pointer.   

References const0_rtx, CONST_INT_P, convert_to_mode(), create_input_operand(), emit_cmp_and_jump_insns(), emit_insn(), emit_jump(), emit_label(), emit_library_call(), emit_move_insn(), emit_stack_probe(), expand_binop(), force_operand(), gcc_assert, gen_blockage(), gen_int_mode(), gen_label_rtx(), GET_MODE, i, INTVAL, LCT_THROW, maybe_expand_insn(), memory_address, NULL_RTX, offset, OPTAB_WIDEN, plus_constant(), PROBE_INTERVAL, simplify_gen_binary(), stack_check_libfunc, STACK_GROW_OFF, STACK_GROW_OP, STACK_GROW_OPTAB, stack_pointer_rtx, and targetm.

Referenced by allocate_dynamic_stack_space(), and expand_function_end().

◆ promote_decl_mode()

machine_mode promote_decl_mode ( const_tree decl,
int * punsignedp )
Use one of promote_mode or promote_function_mode to find the promoted
mode of DECL.  If PUNSIGNEDP is not NULL, store there the unsignedness
of DECL after promotion.   

References current_function_decl, DECL_BY_REFERENCE, DECL_MODE, promote_function_mode(), promote_mode(), TREE_CODE, TREE_TYPE, and TYPE_UNSIGNED.

Referenced by expand_expr_real_1(), expand_function_start(), expand_one_register_var(), promote_ssa_mode(), and store_constructor().

◆ promote_function_mode()

machine_mode promote_function_mode ( const_tree type,
machine_mode mode,
int * punsignedp,
const_tree funtype,
int for_return )
Return the mode to use to pass or return a scalar of TYPE and MODE.
PUNSIGNEDP points to the signedness of the type and may be adjusted
to show what signedness to use on extension operations.

FOR_RETURN is nonzero if the caller is promoting the return value
of FNDECL, else it is for promoting args.   

References INTEGRAL_MODE_P, NULL_TREE, targetm, and TREE_CODE.

Referenced by assign_parm_find_data_types(), assign_parm_setup_reg(), emit_library_call_value_1(), expand_call(), expand_expr_real_1(), expand_function_end(), expand_value_return(), initialize_argument_information(), prepare_libcall_arg(), promote_decl_mode(), and setup_incoming_promotions().

◆ promote_mode()

machine_mode promote_mode ( const_tree type,
machine_mode mode,
int * punsignedp )
Return the mode to use to store a scalar of TYPE and MODE.
PUNSIGNEDP points to the signedness of the type and may be adjusted
to show what signedness to use on extension operations.   

References as_a(), NULL_TREE, targetm, TREE_CODE, TREE_TYPE, and TYPE_ADDR_SPACE.

Referenced by assign_temp(), default_promote_function_mode(), default_promote_function_mode_always_promote(), expand_cond_expr_using_cmove(), precompute_arguments(), promote_decl_mode(), and promote_ssa_mode().

◆ promote_ssa_mode()

machine_mode promote_ssa_mode ( const_tree name,
int * punsignedp )
Return the promoted mode for name.  If it is a named SSA_NAME, it
is the same as promote_decl_mode.  Otherwise, it is the promoted
mode of a temp decl of same type as the SSA_NAME, if we had created
one.   

References gcc_assert, promote_decl_mode(), promote_mode(), SSA_NAME_VAR, TREE_CODE, TREE_TYPE, TYPE_MODE, and TYPE_UNSIGNED.

Referenced by assign_parm_setup_block(), expand_expr_real_1(), expand_function_start(), expand_one_ssa_partition(), get_temp_reg(), gimple_can_coalesce_p(), insert_value_copy_on_edge(), and set_rtl().

◆ record_new_stack_level()

void record_new_stack_level ( void )
Record a new stack level for the current function.  This should be called
whenever we allocate or deallocate dynamic stack space.   

References cfun, global_options, UI_SJLJ, update_nonlocal_goto_save_area(), and update_sjlj_context().

Referenced by allocate_dynamic_stack_space(), expand_call(), and expand_stack_restore().

◆ round_push()

static rtx round_push ( rtx size)
static
Round the size of a block to be pushed up to the boundary required
by this machine.  SIZE is the desired size, which need not be constant.   

References CONST_INT_P, crtl, expand_binop(), expand_divmod(), expand_mult(), force_operand(), GEN_INT, INTVAL, MAX_SUPPORTED_STACK_ALIGNMENT, NULL_RTX, OPTAB_LIB_WIDEN, plus_constant(), SUPPORTS_STACK_ALIGNMENT, and virtual_preferred_stack_boundary_rtx.

Referenced by get_dynamic_stack_size().

◆ rtx_to_tree_code()

int rtx_to_tree_code ( enum rtx_code code)
Look up the tree code for a given rtx code
to provide the arithmetic operation for real_arithmetic.
The function returns an int because the caller may not know
what `enum tree_code' means.   

Referenced by simplify_const_binary_operation().

◆ set_stack_check_libfunc()

◆ trunc_int_for_mode() [1/2]

◆ trunc_int_for_mode() [2/2]

poly_int64 trunc_int_for_mode ( poly_int64 x,
machine_mode mode )
Likewise for polynomial values, using the sign-extended representation
for each individual coefficient.   

References poly_int< N, C >::coeffs, i, NUM_POLY_INT_COEFFS, and trunc_int_for_mode().

◆ update_nonlocal_goto_save_area()

void update_nonlocal_goto_save_area ( void )
Invoke emit_stack_save on the nonlocal_goto_save_area for the current
function.  This should be called whenever we allocate or deallocate
dynamic stack space.   

References build4(), cfun, emit_stack_save(), expand_expr(), EXPAND_WRITE, integer_one_node, NULL_RTX, NULL_TREE, SAVE_NONLOCAL, and TREE_TYPE.

Referenced by expand_function_start(), and record_new_stack_level().

◆ use_anchored_address()

rtx use_anchored_address ( rtx x)
If X is a memory reference to a member of an object block, try rewriting
it to use an anchor instead.  Return the new memory reference on success
and the old one on failure.   

References CONST_INT_P, cse_not_expected, force_reg(), GET_CODE, GET_MODE, get_section_anchor(), INTVAL, MEM_P, NULL, offset, place_block_symbol(), plus_constant(), replace_equiv_address(), SYMBOL_REF_ANCHOR_P, SYMBOL_REF_BLOCK, SYMBOL_REF_BLOCK_OFFSET, SYMBOL_REF_HAS_BLOCK_INFO_P, SYMBOL_REF_TLS_MODEL, targetm, and XEXP.

Referenced by emit_move_insn(), emit_move_multi_word(), expand_expr_constant(), expand_expr_real_1(), and validize_mem().

◆ validize_mem()

Variable Documentation

◆ stack_check_libfunc

rtx stack_check_libfunc
static
A front end may want to override GCC's stack checking by providing a
run-time routine to call to check the stack, so provide a mechanism for
calling that routine.   

Referenced by probe_stack_range(), and set_stack_check_libfunc().

◆ suppress_reg_args_size

bool suppress_reg_args_size
static
Controls the behavior of {anti_,}adjust_stack.   

Referenced by adjust_stack_1(), and allocate_dynamic_stack_space().