i386.c

Mac OS X 10.4.9 for x86 Source Code gcc 实现源代码

/* The "default" register map used in 64bit mode.  */
/* APPLE LOCAL begin mainline 2006-02-17 4356747 stack realign */
int const dbx64_register_map[FIRST_PSEUDO_REGISTER+1] =
{
  0, 1, 2, 3, 4, 5, 6, 7,		/* general regs */
  33, 34, 35, 36, 37, 38, 39, 40,	/* fp regs */
  -1, -1, -1, -1, -1,			/* arg, flags, fpsr, dir, frame */
  17, 18, 19, 20, 21, 22, 23, 24,	/* SSE */
  41, 42, 43, 44, 45, 46, 47, 48,       /* MMX */
  8,9,10,11,12,13,14,15,		/* extended integer registers */
  25, 26, 27, 28, 29, 30, 31, 32,	/* extended SSE registers */
  16					/* return column */
};
/* APPLE LOCAL end mainline 2006-02-17 4356747 stack realign */

/* Define the register numbers to be used in Dwarf debugging information.
   The SVR4 reference port C compiler uses the following register numbers
   in its Dwarf output code:
	0 for %eax (gcc regno = 0)
	1 for %ecx (gcc regno = 2)
	2 for %edx (gcc regno = 1)
	3 for %ebx (gcc regno = 3)
	4 for %esp (gcc regno = 7)
	5 for %ebp (gcc regno = 6)
	6 for %esi (gcc regno = 4)
	7 for %edi (gcc regno = 5)
   The following three DWARF register numbers are never generated by
   the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
   believes these numbers have these meanings.
	8  for %eip    (no gcc equivalent)
	9  for %eflags (gcc regno = 17)
	10 for %trapno (no gcc equivalent)
   It is not at all clear how we should number the FP stack registers
   for the x86 architecture.  If the version of SDB on x86/svr4 were
   a bit less brain dead with respect to floating-point then we would
   have a precedent to follow with respect to DWARF register numbers
   for x86 FP registers, but the SDB on x86/svr4 is so completely
   broken with respect to FP registers that it is hardly worth thinking
   of it as something to strive for compatibility with.
   The version of x86/svr4 SDB I have at the moment does (partially)
   seem to believe that DWARF register number 11 is associated with
   the x86 register %st(0), but that's about all.  Higher DWARF
   register numbers don't seem to be associated with anything in
   particular, and even for DWARF regno 11, SDB only seems to under-
   stand that it should say that a variable lives in %st(0) (when
   asked via an `=' command) if we said it was in DWARF regno 11,
   but SDB still prints garbage when asked for the value of the
   variable in question (via a `/' command).
   (Also note that the labels SDB prints for various FP stack regs
   when doing an `x' command are all wrong.)
   Note that these problems generally don't affect the native SVR4
   C compiler because it doesn't allow the use of -O with -g and
   because when it is *not* optimizing, it allocates a memory
   location for each floating-point variable, and the memory
   location is what gets described in the DWARF AT_location
   attribute for the variable in question.
   Regardless of the severe mental illness of the x86/svr4 SDB, we
   do something sensible here and we use the following DWARF
   register numbers.  Note that these are all stack-top-relative
   numbers.
	11 for %st(0) (gcc regno = 8)
	12 for %st(1) (gcc regno = 9)
	13 for %st(2) (gcc regno = 10)
	14 for %st(3) (gcc regno = 11)
	15 for %st(4) (gcc regno = 12)
	16 for %st(5) (gcc regno = 13)
	17 for %st(6) (gcc regno = 14)
	18 for %st(7) (gcc regno = 15)
*/
/* APPLE LOCAL begin mainline 2006-02-17 4356747 stack realign */
int const svr4_dbx_register_map[FIRST_PSEUDO_REGISTER+1] =
{
  0, 2, 1, 3, 6, 7, 5, 4,		/* general regs */
  11, 12, 13, 14, 15, 16, 17, 18,	/* fp regs */
  -1, 9, -1, -1, -1,			/* arg, flags, fpsr, dir, frame */
  21, 22, 23, 24, 25, 26, 27, 28,	/* SSE registers */
  29, 30, 31, 32, 33, 34, 35, 36,	/* MMX registers */
  -1, -1, -1, -1, -1, -1, -1, -1,	/* extended integer registers */
  -1, -1, -1, -1, -1, -1, -1, -1,	/* extended SSE registers */
  8					/* return column */
};
/* APPLE LOCAL end mainline 2006-02-17 4356747 stack realign */

/* Test and compare insns in i386.md store the information needed to
   generate branch and scc insns here.  */

rtx ix86_compare_op0 = NULL_RTX;
rtx ix86_compare_op1 = NULL_RTX;

#define MAX_386_STACK_LOCALS 3
/* Size of the register save area.  */
#define X86_64_VARARGS_SIZE (REGPARM_MAX * UNITS_PER_WORD + SSE_REGPARM_MAX * 16)

/* Define the structure for the machine field in struct function.  */

struct stack_local_entry GTY(())
{
  unsigned short mode;
  unsigned short n;
  rtx rtl;
  struct stack_local_entry *next;
};

/* Structure describing stack frame layout.
   Stack grows downward:

   [arguments]
					      <- ARG_POINTER
   saved pc

   saved frame pointer if frame_pointer_needed
					      <- HARD_FRAME_POINTER
   [saved regs]

   [padding1]          \
		        )
   [va_arg registers]  (
		        > to_allocate	      <- FRAME_POINTER
   [frame]	       (
		        )
   [padding2]	       /
  */
struct ix86_frame
{
  int nregs;
  int padding1;
  int va_arg_size;
  HOST_WIDE_INT frame;
  int padding2;
  int outgoing_arguments_size;
  int red_zone_size;

  HOST_WIDE_INT to_allocate;
  /* The offsets relative to ARG_POINTER.  */
  HOST_WIDE_INT frame_pointer_offset;
  HOST_WIDE_INT hard_frame_pointer_offset;
  HOST_WIDE_INT stack_pointer_offset;

  /* When save_regs_using_mov is set, emit prologue using
     move instead of push instructions.  */
  bool save_regs_using_mov;
};

/* Used to enable/disable debugging features.  */
const char *ix86_debug_arg_string, *ix86_debug_addr_string;
/* Code model option as passed by user.  */
const char *ix86_cmodel_string;
/* Parsed value.  */
enum cmodel ix86_cmodel;
/* Asm dialect.  */
const char *ix86_asm_string;
enum asm_dialect ix86_asm_dialect = ASM_ATT;
/* TLS dialext.  */
const char *ix86_tls_dialect_string;
enum tls_dialect ix86_tls_dialect = TLS_DIALECT_GNU;

/* Which unit we are generating floating point math for.  */
enum fpmath_unit ix86_fpmath;

/* Which cpu are we scheduling for.  */
enum processor_type ix86_tune;
/* Which instruction set architecture to use.  */
enum processor_type ix86_arch;

/* Strings to hold which cpu and instruction set architecture  to use.  */
const char *ix86_tune_string;		/* for -mtune=<xxx> */
const char *ix86_arch_string;		/* for -march=<xxx> */
const char *ix86_fpmath_string;		/* for -mfpmath=<xxx> */

/* # of registers to use to pass arguments.  */
const char *ix86_regparm_string;

/* true if sse prefetch instruction is not NOOP.  */
int x86_prefetch_sse;

/* ix86_regparm_string as a number */
int ix86_regparm;

/* Alignment to use for loops and jumps:  */

/* Power of two alignment for loops.  */
const char *ix86_align_loops_string;

/* Power of two alignment for non-loop jumps.  */
const char *ix86_align_jumps_string;

/* Power of two alignment for stack boundary in bytes.  */
const char *ix86_preferred_stack_boundary_string;

/* APPLE LOCAL begin 4356747 stack realign */
/* -mstackrealign option */
/* extern *//* Note #1 to merger: This decl will move to "i386.opt" in
	       the next FSF merge, and then we'll need an 'extern'
	       here.  */
const char *ix86_force_align_arg_pointer;
static const char ix86_force_align_arg_pointer_string[] = "force_align_arg_pointer";
/* Note #2 to merger: The -mstackrealign stuff was submitted to FSF trunk
on 10feb2006: http://gcc.gnu.org/ml/gcc-patches/2006-02/msg00854.html
Apple needed this enhancement promptly (before the FSF acted on that patch), so
A) I copied in a previous, necessary trunk patch:
   http://gcc.gnu.org/ml/gcc-patches/2005-10/msg00931.html
   This patch is marked "mainline 2006-02-17 4356747 stack realign".
B) I added my own patch (URL above), marked "4356747 stack realign".
C) I had to modify my patch to work without the "i386.opt" file (I was too lazy
to merge this non-trivial change into Apple's Curry branch).
HTH.  */
/* APPLE LOCAL end 4356747 stack realign */

/* Preferred alignment for stack boundary in bits.  */
unsigned int ix86_preferred_stack_boundary;

/* Values 1-5: see jump.c */
int ix86_branch_cost;
const char *ix86_branch_cost_string;

/* Power of two alignment for functions.  */
const char *ix86_align_funcs_string;

/* Prefix built by ASM_GENERATE_INTERNAL_LABEL.  */
char internal_label_prefix[16];
int internal_label_prefix_len;

static void output_pic_addr_const (FILE *, rtx, int);
static void put_condition_code (enum rtx_code, enum machine_mode,
				int, int, FILE *);
static const char *get_some_local_dynamic_name (void);
static int get_some_local_dynamic_name_1 (rtx *, void *);
static rtx ix86_expand_int_compare (enum rtx_code, rtx, rtx);
static enum rtx_code ix86_prepare_fp_compare_args (enum rtx_code, rtx *,
						   rtx *);
static bool ix86_fixed_condition_code_regs (unsigned int *, unsigned int *);
static enum machine_mode ix86_cc_modes_compatible (enum machine_mode,
						   enum machine_mode);
static rtx get_thread_pointer (int);
static rtx legitimize_tls_address (rtx, enum tls_model, int);
static void get_pc_thunk_name (char [32], unsigned int);
static rtx gen_push (rtx);
static int ix86_flags_dependant (rtx, rtx, enum attr_type);
static int ix86_agi_dependant (rtx, rtx, enum attr_type);
static struct machine_function * ix86_init_machine_status (void);
static int ix86_split_to_parts (rtx, rtx *, enum machine_mode);
static int ix86_nsaved_regs (void);
static void ix86_emit_save_regs (void);
static void ix86_emit_save_regs_using_mov (rtx, HOST_WIDE_INT);
static void ix86_emit_restore_regs_using_mov (rtx, HOST_WIDE_INT, int);
static void ix86_output_function_epilogue (FILE *, HOST_WIDE_INT);
static HOST_WIDE_INT ix86_GOT_alias_set (void);
static void ix86_adjust_counter (rtx, HOST_WIDE_INT);
static rtx ix86_expand_aligntest (rtx, int);
static void ix86_expand_strlensi_unroll_1 (rtx, rtx, rtx);
static int ix86_issue_rate (void);
static int ix86_adjust_cost (rtx, rtx, rtx, int);
static int ia32_multipass_dfa_lookahead (void);
static void ix86_init_mmx_sse_builtins (void);
static rtx x86_this_parameter (tree);
static void x86_output_mi_thunk (FILE *, tree, HOST_WIDE_INT,
				 HOST_WIDE_INT, tree);
static bool x86_can_output_mi_thunk (tree, HOST_WIDE_INT, HOST_WIDE_INT, tree);
static void x86_file_start (void);
static void ix86_reorg (void);
static bool ix86_expand_carry_flag_compare (enum rtx_code, rtx, rtx, rtx*);
static tree ix86_build_builtin_va_list (void);
static void ix86_setup_incoming_varargs (CUMULATIVE_ARGS *, enum machine_mode,
					 tree, int *, int);
static tree ix86_gimplify_va_arg (tree, tree, tree *, tree *);
static bool ix86_vector_mode_supported_p (enum machine_mode);

static int ix86_address_cost (rtx);
static bool ix86_cannot_force_const_mem (rtx);
static rtx ix86_delegitimize_address (rtx);

struct builtin_description;
static rtx ix86_expand_sse_comi (const struct builtin_description *,
				 tree, rtx);
static rtx ix86_expand_sse_compare (const struct builtin_description *,
				    tree, rtx);
static rtx ix86_expand_unop1_builtin (enum insn_code, tree, rtx);
static rtx ix86_expand_unop_builtin (enum insn_code, tree, rtx, int);
static rtx ix86_expand_binop_builtin (enum insn_code, tree, rtx);
static rtx ix86_expand_store_builtin (enum insn_code, tree);
static rtx safe_vector_operand (rtx, enum machine_mode);
static rtx ix86_expand_fp_compare (enum rtx_code, rtx, rtx, rtx, rtx *, rtx *);
static int ix86_fp_comparison_arithmetics_cost (enum rtx_code code);
static int ix86_fp_comparison_fcomi_cost (enum rtx_code code);
static int ix86_fp_comparison_sahf_cost (enum rtx_code code);
static int ix86_fp_comparison_cost (enum rtx_code code);
static unsigned int ix86_select_alt_pic_regnum (void);
static int ix86_save_reg (unsigned int, int);
static void ix86_compute_frame_layout (struct ix86_frame *);
static int ix86_comp_type_attributes (tree, tree);
static int ix86_function_regparm (tree, tree);
const struct attribute_spec ix86_attribute_table[];
static bool ix86_function_ok_for_sibcall (tree, tree);
/* APPLE LOCAL begin mainline 2005-09-20 4205103 */
static tree ix86_handle_cconv_attribute (tree *, tree, tree, int, bool *);
static int ix86_value_regno (enum machine_mode, tree, tree);
/* APPLE LOCAL end mainline 2005-09-20 4205103 */
static bool contains_128bit_aligned_vector_p (tree);
static rtx ix86_struct_value_rtx (tree, int);
static bool ix86_ms_bitfield_layout_p (tree);
static tree ix86_handle_struct_attribute (tree *, tree, tree, int, bool *);
static int extended_reg_mentioned_1 (rtx *, void *);
/* APPLE LOCAL begin why is this local? */
#if TARGET_MACHO
static bool ix86_binds_local_p (tree);