/* Output Dwarf2 format symbol table information from the GNU C compiler.
Copyright (C) 1992, 1993, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002
Free Software Foundation, Inc.
Contributed by Gary Funck (gary@intrepid.com).
Derived from DWARF 1 implementation of Ron Guilmette (rfg@monkeys.com).
Extensively modified by Jason Merrill (jason@cygnus.com).
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, 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 COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
/* TODO: Emit .debug_line header even when there are no functions, since
the file numbers are used by .debug_info. Alternately, leave
out locations for types and decls.
Avoid talking about ctors and op= for PODs.
Factor out common prologue sequences into multiple CIEs. */
/* The first part of this file deals with the DWARF 2 frame unwind
information, which is also used by the GCC efficient exception handling
mechanism. The second part, controlled only by an #ifdef
DWARF2_DEBUGGING_INFO, deals with the other DWARF 2 debugging
information. */
#include "config.h"
#include "system.h"
#include "tree.h"
#include "flags.h"
#include "real.h"
#include "rtl.h"
#include "hard-reg-set.h"
#include "regs.h"
#include "insn-config.h"
#include "reload.h"
#include "function.h"
#include "output.h"
#include "expr.h"
#include "libfuncs.h"
#include "except.h"
#include "dwarf2.h"
#include "dwarf2out.h"
#include "dwarf2asm.h"
#include "toplev.h"
#include "varray.h"
#include "ggc.h"
#include "md5.h"
#include "tm_p.h"
#include "diagnostic.h"
#include "debug.h"
#include "target.h"
#include "langhooks.h"
#include "hashtable.h"
#ifdef DWARF2_DEBUGGING_INFO
static void dwarf2out_source_line PARAMS ((unsigned int, const char *));
#endif
/* DWARF2 Abbreviation Glossary:
CFA = Canonical Frame Address
a fixed address on the stack which identifies a call frame.
We define it to be the value of SP just before the call insn.
The CFA register and offset, which may change during the course
of the function, are used to calculate its value at runtime.
CFI = Call Frame Instruction
an instruction for the DWARF2 abstract machine
CIE = Common Information Entry
information describing information common to one or more FDEs
DIE = Debugging Information Entry
FDE = Frame Description Entry
information describing the stack call frame, in particular,
how to restore registers
DW_CFA_... = DWARF2 CFA call frame instruction
DW_TAG_... = DWARF2 DIE tag */
/* Decide whether we want to emit frame unwind information for the current
translation unit. */
int
dwarf2out_do_frame ()
{
return (write_symbols == DWARF2_DEBUG
|| write_symbols == VMS_AND_DWARF2_DEBUG
#ifdef DWARF2_FRAME_INFO
|| DWARF2_FRAME_INFO
#endif
#ifdef DWARF2_UNWIND_INFO
|| flag_unwind_tables
|| (flag_exceptions && ! USING_SJLJ_EXCEPTIONS)
#endif
);
}
/* The size of the target's pointer type. */
#ifndef PTR_SIZE
#define PTR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif
/* Default version of targetm.eh_frame_section. Note this must appear
outside the DWARF2_DEBUGGING_INFO || DWARF2_UNWIND_INFO macro
guards. */
void
default_eh_frame_section ()
{
#ifdef EH_FRAME_SECTION_NAME
named_section_flags (EH_FRAME_SECTION_NAME, SECTION_WRITE);
#else
tree label = get_file_function_name ('F');
data_section ();
ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (PTR_SIZE));
(*targetm.asm_out.globalize_label) (asm_out_file, IDENTIFIER_POINTER (label));
ASM_OUTPUT_LABEL (asm_out_file, IDENTIFIER_POINTER (label));
#endif
}
/* Array of RTXes referenced by the debugging information, which therefore
must be kept around forever. */
static GTY(()) varray_type used_rtx_varray;
/* A pointer to the base of a list of incomplete types which might be
completed at some later time. incomplete_types_list needs to be a VARRAY
because we want to tell the garbage collector about it. */
static GTY(()) varray_type incomplete_types;
/* A pointer to the base of a table of references to declaration
scopes. This table is a display which tracks the nesting
of declaration scopes at the current scope and containing
scopes. This table is used to find the proper place to
define type declaration DIE's. */
static GTY(()) varray_type decl_scope_table;
#if defined (DWARF2_DEBUGGING_INFO) || defined (DWARF2_UNWIND_INFO)
/* How to start an assembler comment. */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif
typedef struct dw_cfi_struct *dw_cfi_ref;
typedef struct dw_fde_struct *dw_fde_ref;
typedef union dw_cfi_oprnd_struct *dw_cfi_oprnd_ref;
/* Call frames are described using a sequence of Call Frame
Information instructions. The register number, offset
and address fields are provided as possible operands;
their use is selected by the opcode field. */
typedef union dw_cfi_oprnd_struct
{
unsigned long dw_cfi_reg_num;
long int dw_cfi_offset;
const char *dw_cfi_addr;
struct dw_loc_descr_struct *dw_cfi_loc;
}
dw_cfi_oprnd;
typedef struct dw_cfi_struct
{
dw_cfi_ref dw_cfi_next;
enum dwarf_call_frame_info dw_cfi_opc;
dw_cfi_oprnd dw_cfi_oprnd1;
dw_cfi_oprnd dw_cfi_oprnd2;
}
dw_cfi_node;
/* This is how we define the location of the CFA. We use to handle it
as REG + OFFSET all the time, but now it can be more complex.
It can now be either REG + CFA_OFFSET or *(REG + BASE_OFFSET) + CFA_OFFSET.
Instead of passing around REG and OFFSET, we pass a copy
of this structure. */
typedef struct cfa_loc
{
unsigned long reg;
long offset;
long base_offset;
int indirect; /* 1 if CFA is accessed via a dereference. */
} dw_cfa_location;
/* All call frame descriptions (FDE's) in the GCC generated DWARF
refer to a single Common Information Entry (CIE), defined at
the beginning of the .debug_frame section. This use of a single
CIE obviates the need to keep track of multiple CIE's
in the DWARF generation routines below. */
typedef struct dw_fde_struct
{
const char *dw_fde_begin;
const char *dw_fde_current_label;
const char *dw_fde_end;
dw_cfi_ref dw_fde_cfi;
unsigned funcdef_number;
unsigned all_throwers_are_sibcalls : 1;
unsigned nothrow : 1;
unsigned uses_eh_lsda : 1;
}
dw_fde_node;
/* Maximum size (in bytes) of an artificially generated label. */
#define MAX_ARTIFICIAL_LABEL_BYTES 30
/* The size of addresses as they appear in the Dwarf 2 data.
Some architectures use word addresses to refer to code locations,
but Dwarf 2 info always uses byte addresses. On such machines,
Dwarf 2 addresses need to be larger than the architecture's
pointers. */
#ifndef DWARF2_ADDR_SIZE
#define DWARF2_ADDR_SIZE (POINTER_SIZE / BITS_PER_UNIT)
#endif
/* The size in bytes of a DWARF field indicating an offset or length
relative to a debug info section, specified to be 4 bytes in the
DWARF-2 specification. The SGI/MIPS ABI defines it to be the same
as PTR_SIZE. */
#ifndef DWARF_OFFSET_SIZE
#define DWARF_OFFSET_SIZE 4
#endif
#define DWARF_VERSION 2
/* Round SIZE up to the nearest BOUNDARY. */
#define DWARF_ROUND(SIZE,BOUNDARY) \
((((SIZE) + (BOUNDARY) - 1) / (BOUNDARY)) * (BOUNDARY))
/* Offsets recorded in opcodes are a multiple of this alignment factor. */
#ifndef DWARF_CIE_DATA_ALIGNMENT
#ifdef STACK_GROWS_DOWNWARD
#define DWARF_CIE_DATA_ALIGNMENT (-((int) UNITS_PER_WORD))
#else
#define DWARF_CIE_DATA_ALIGNMENT ((int) UNITS_PER_WORD)
#endif
#endif
/* A pointer to the base of a table that contains frame description
information for each routine. */
static dw_fde_ref fde_table;
/* Number of elements currently allocated for fde_table. */
static unsigned fde_table_allocated;
/* Number of elements in fde_table currently in use. */
static unsigned fde_table_in_use;
/* Size (in elements) of increments by which we may expand the
fde_table. */
#define FDE_TABLE_INCREMENT 256
/* A list of call frame insns for the CIE. */
static dw_cfi_ref cie_cfi_head;
/* Some DWARF extensions (e.g., MIPS/SGI) implement a subprogram
attribute that accelerates the lookup of the FDE associated
with the subprogram. This variable holds the table index of the FDE
associated with the current function (body) definition. */
static unsigned current_funcdef_fde;
struct ht *debug_str_hash;
struct indirect_string_node
{
struct ht_identifier id;
unsigned int refcount;
unsigned int form;
char *label;
};
/* Forward declarations for functions defined in this file. */
static char *stripattributes PARAMS ((const char *));
static const char *dwarf_cfi_name PARAMS ((unsigned));
static dw_cfi_ref new_cfi PARAMS ((void));
static void add_cfi PARAMS ((dw_cfi_ref *, dw_cfi_ref));
static void add_fde_cfi PARAMS ((const char *, dw_cfi_ref));
static void lookup_cfa_1 PARAMS ((dw_cfi_ref,
dw_cfa_location *));
static void lookup_cfa PARAMS ((dw_cfa_location *));
static void reg_save PARAMS ((const char *, unsigned,
unsigned, long));
static void initial_return_save PARAMS ((rtx));
static long stack_adjust_offset PARAMS ((rtx));
static void output_cfi PARAMS ((dw_cfi_ref, dw_fde_ref, int));
static void output_call_frame_info PARAMS ((int));
static void dwarf2out_stack_adjust PARAMS ((rtx));
static void queue_reg_save PARAMS ((const char *, rtx, long));
static void flush_queued_reg_saves PARAMS ((void));
static bool clobbers_queued_reg_save PARAMS ((rtx));
static void dwarf2out_frame_debug_expr PARAMS ((rtx, const char *));
/* Support for complex CFA locations. */
static void output_cfa_loc PARAMS ((dw_cfi_ref));
static void get_cfa_from_loc_descr PARAMS ((dw_cfa_location *,
struct dw_loc_descr_struct *));
static struct dw_loc_descr_struct *build_cfa_loc
PARAMS ((dw_cfa_location *));
static void def_cfa_1 PARAMS ((const char *,
dw_cfa_location *));
/* How to start an assembler comment. */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif
/* Data and reference forms for relocatable data. */
#define DW_FORM_data (DWARF_OFFSET_SIZE == 8 ? DW_FORM_data8 : DW_FORM_data4)
#define DW_FORM_ref (DWARF_OFFSET_SIZE == 8 ? DW_FORM_ref8 : DW_FORM_ref4)
#ifndef DEBUG_FRAME_SECTION
#define DEBUG_FRAME_SECTION ".debug_frame"
#endif
#ifndef FUNC_BEGIN_LABEL
#define FUNC_BEGIN_LABEL "LFB"
#endif
#ifndef FUNC_END_LABEL
#define FUNC_END_LABEL "LFE"
#endif
#define FRAME_BEGIN_LABEL "Lframe"
#define CIE_AFTER_SIZE_LABEL "LSCIE"
#define CIE_END_LABEL "LECIE"
#define FDE_LABEL "LSFDE"
#define FDE_AFTER_SIZE_LABEL "LASFDE"
#define FDE_END_LABEL "LEFDE"
#define LINE_NUMBER_BEGIN_LABEL "LSLT"
#define LINE_NUMBER_END_LABEL "LELT"
#define LN_PROLOG_AS_LABEL "LASLTP"
#define LN_PROLOG_END_LABEL "LELTP"
#define DIE_LABEL_PREFIX "DW"
/* The DWARF 2 CFA column which tracks the return address. Normally this
is the column for PC, or the first column after all of the hard
registers. */
#ifndef DWARF_FRAME_RETURN_COLUMN
#ifdef PC_REGNUM
#define DWARF_FRAME_RETURN_COLUMN DWARF_FRAME_REGNUM (PC_REGNUM)
#else
#define DWARF_FRAME_RETURN_COLUMN DWARF_FRAME_REGISTERS
#endif
#endif
/* The mapping from gcc register number to DWARF 2 CFA column number. By
default, we just provide columns for all registers. */
#ifndef DWARF_FRAME_REGNUM
#define DWARF_FRAME_REGNUM(REG) DBX_REGISTER_NUMBER (REG)
#endif
/* The offset from the incoming value of %sp to the top of the stack frame
for the current function. */
#ifndef INCOMING_FRAME_SP_OFFSET
#define INCOMING_FRAME_SP_OFFSET 0
#endif
/* Hook used by __throw. */
rtx
expand_builtin_dwarf_fp_regnum ()
{
return GEN_INT (DWARF_FRAME_REGNUM (HARD_FRAME_POINTER_REGNUM));
}
/* Return a pointer to a copy of the section string name S with all
attributes stripped off, and an asterisk prepended (for assemble_name). */
static inline char *
stripattributes (s)
const char *s;
{
char *stripped = xmalloc (strlen (s) + 2);
char *p = stripped;
*p++ = '*';
while (*s && *s != ',')
*p++ = *s++;
*p = '\0';
return stripped;
}
/* Generate code to initialize the register size table. */
void
expand_builtin_init_dwarf_reg_sizes (address)
tree address;
{
int i;
enum machine_mode mode = TYPE_MODE (char_type_node);
rtx addr = expand_expr (address, NULL_RTX, VOIDmode, 0);
rtx mem = gen_rtx_MEM (BLKmode, addr);
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
if (DWARF_FRAME_REGNUM (i) < DWARF_FRAME_REGISTERS)
{
HOST_WIDE_INT offset = DWARF_FRAME_REGNUM (i) * GET_MODE_SIZE (mode);
HOST_WIDE_INT size = GET_MODE_SIZE (reg_raw_mode[i]);
if (offset < 0)
continue;
emit_move_insn (adjust_address (mem, mode, offset), GEN_INT (size));
}
}
/* Convert a DWARF call frame info. operation to its string name */
static const char *
dwarf_cfi_name (cfi_opc)
unsigned cfi_opc;
{
switch (cfi_opc)
{
case DW_CFA_advance_loc:
return "DW_CFA_advance_loc";
case DW_CFA_offset:
return "DW_CFA_offset";
case DW_CFA_restore:
return "DW_CFA_restore";
case DW_CFA_nop:
return "DW_CFA_nop";
case DW_CFA_set_loc:
return "DW_CFA_set_loc";
case DW_CFA_advance_loc1:
return "DW_CFA_advance_loc1";
case DW_CFA_advance_loc2:
return "DW_CFA_advance_loc2";
case DW_CFA_advance_loc4:
return "DW_CFA_advance_loc4";
case DW_CFA_offset_extended:
return "DW_CFA_offset_extended";
case DW_CFA_restore_extended:
return "DW_CFA_restore_extended";
case DW_CFA_undefined:
return "DW_CFA_undefined";
case DW_CFA_same_value:
return "DW_CFA_same_value";
case DW_CFA_register:
return "DW_CFA_register";
case DW_CFA_remember_state:
return "DW_CFA_remember_state";
case DW_CFA_restore_state:
return "DW_CFA_restore_state";
case DW_CFA_def_cfa:
return "DW_CFA_def_cfa";
case DW_CFA_def_cfa_register:
return "DW_CFA_def_cfa_register";
case DW_CFA_def_cfa_offset:
return "DW_CFA_def_cfa_offset";
/* DWARF 3 */
case DW_CFA_def_cfa_expression:
return "DW_CFA_def_cfa_expression";
case DW_CFA_expression:
return "DW_CFA_expression";
case DW_CFA_offset_extended_sf:
return "DW_CFA_offset_extended_sf";
case DW_CFA_def_cfa_sf:
return "DW_CFA_def_cfa_sf";
case DW_CFA_def_cfa_offset_sf:
return "DW_CFA_def_cfa_offset_sf";
/* SGI/MIPS specific */
case DW_CFA_MIPS_advance_loc8:
return "DW_CFA_MIPS_advance_loc8";
/* GNU extensions */
case DW_CFA_GNU_window_save:
return "DW_CFA_GNU_window_save";
case DW_CFA_GNU_args_size:
return "DW_CFA_GNU_args_size";
case DW_CFA_GNU_negative_offset_extended:
return "DW_CFA_GNU_negative_offset_extended";
default:
return "DW_CFA_<unknown>";
}
}
/* Return a pointer to a newly allocated Call Frame Instruction. */
static inline dw_cfi_ref
new_cfi ()
{
dw_cfi_ref cfi = (dw_cfi_ref) xmalloc (sizeof (dw_cfi_node));
cfi->dw_cfi_next = NULL;
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = 0;
cfi->dw_cfi_oprnd2.dw_cfi_reg_num = 0;
return cfi;
}
/* Add a Call Frame Instruction to list of instructions. */
static inline void
add_cfi (list_head, cfi)
dw_cfi_ref *list_head;
dw_cfi_ref cfi;
{
dw_cfi_ref *p;
/* Find the end of the chain. */
for (p = list_head; (*p) != NULL; p = &(*p)->dw_cfi_next)
;
*p = cfi;
}
/* Generate a new label for the CFI info to refer to. */
char *
dwarf2out_cfi_label ()
{
static char label[20];
static unsigned long label_num = 0;
ASM_GENERATE_INTERNAL_LABEL (label, "LCFI", label_num++);
ASM_OUTPUT_LABEL (asm_out_file, label);
return label;
}
/* Add CFI to the current fde at the PC value indicated by LABEL if specified,
or to the CIE if LABEL is NULL. */
static void
add_fde_cfi (label, cfi)
const char *label;
dw_cfi_ref cfi;
{
if (label)
{
dw_fde_ref fde = &fde_table[fde_table_in_use - 1];
if (*label == 0)
label = dwarf2out_cfi_label ();
if (fde->dw_fde_current_label == NULL
|| strcmp (label, fde->dw_fde_current_label) != 0)
{
dw_cfi_ref xcfi;
fde->dw_fde_current_label = label = xstrdup (label);
/* Set the location counter to the new label. */
xcfi = new_cfi ();
xcfi->dw_cfi_opc = DW_CFA_advance_loc4;
xcfi->dw_cfi_oprnd1.dw_cfi_addr = label;
add_cfi (&fde->dw_fde_cfi, xcfi);
}
add_cfi (&fde->dw_fde_cfi, cfi);
}
else
add_cfi (&cie_cfi_head, cfi);
}
/* Subroutine of lookup_cfa. */
static inline void
lookup_cfa_1 (cfi, loc)
dw_cfi_ref cfi;
dw_cfa_location *loc;
{
switch (cfi->dw_cfi_opc)
{
case DW_CFA_def_cfa_offset:
loc->offset = cfi->dw_cfi_oprnd1.dw_cfi_offset;
break;
case DW_CFA_def_cfa_register:
loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
break;
case DW_CFA_def_cfa:
loc->reg = cfi->dw_cfi_oprnd1.dw_cfi_reg_num;
loc->offset = cfi->dw_cfi_oprnd2.dw_cfi_offset;
break;
case DW_CFA_def_cfa_expression:
get_cfa_from_loc_descr (loc, cfi->dw_cfi_oprnd1.dw_cfi_loc);
break;
default:
break;
}
}
/* Find the previous value for the CFA. */
static void
lookup_cfa (loc)
dw_cfa_location *loc;
{
dw_cfi_ref cfi;
loc->reg = (unsigned long) -1;
loc->offset = 0;
loc->indirect = 0;
loc->base_offset = 0;
for (cfi = cie_cfi_head; cfi; cfi = cfi->dw_cfi_next)
lookup_cfa_1 (cfi, loc);
if (fde_table_in_use)
{
dw_fde_ref fde = &fde_table[fde_table_in_use - 1];
for (cfi = fde->dw_fde_cfi; cfi; cfi = cfi->dw_cfi_next)
lookup_cfa_1 (cfi, loc);
}
}
/* The current rule for calculating the DWARF2 canonical frame address. */
static dw_cfa_location cfa;
/* The register used for saving registers to the stack, and its offset
from the CFA. */
static dw_cfa_location cfa_store;
/* The running total of the size of arguments pushed onto the stack. */
static long args_size;
/* The last args_size we actually output. */
static long old_args_size;
/* Entry point to update the canonical frame address (CFA).
LABEL is passed to add_fde_cfi. The value of CFA is now to be
calculated from REG+OFFSET. */
void
dwarf2out_def_cfa (label, reg, offset)
const char *label;
unsigned reg;
long offset;
{
dw_cfa_location loc;
loc.indirect = 0;
loc.base_offset = 0;
loc.reg = reg;
loc.offset = offset;
def_cfa_1 (label, &loc);
}
/* This routine does the actual work. The CFA is now calculated from
the dw_cfa_location structure. */
static void
def_cfa_1 (label, loc_p)
const char *label;
dw_cfa_location *loc_p;
{
dw_cfi_ref cfi;
dw_cfa_location old_cfa, loc;
cfa = *loc_p;
loc = *loc_p;
if (cfa_store.reg == loc.reg && loc.indirect == 0)
cfa_store.offset = loc.offset;
loc.reg = DWARF_FRAME_REGNUM (loc.reg);
lookup_cfa (&old_cfa);
/* If nothing changed, no need to issue any call frame instructions. */
if (loc.reg == old_cfa.reg && loc.offset == old_cfa.offset
&& loc.indirect == old_cfa.indirect
&& (loc.indirect == 0 || loc.base_offset == old_cfa.base_offset))
return;
cfi = new_cfi ();
if (loc.reg == old_cfa.reg && !loc.indirect)
{
/* Construct a "DW_CFA_def_cfa_offset <offset>" instruction,
indicating the CFA register did not change but the offset
did. */
cfi->dw_cfi_opc = DW_CFA_def_cfa_offset;
cfi->dw_cfi_oprnd1.dw_cfi_offset = loc.offset;
}
#ifndef MIPS_DEBUGGING_INFO /* SGI dbx thinks this means no offset. */
else if (loc.offset == old_cfa.offset && old_cfa.reg != (unsigned long) -1
&& !loc.indirect)
{
/* Construct a "DW_CFA_def_cfa_register <register>" instruction,
indicating the CFA register has changed to <register> but the
offset has not changed. */
cfi->dw_cfi_opc = DW_CFA_def_cfa_register;
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
}
#endif
else if (loc.indirect == 0)
{
/* Construct a "DW_CFA_def_cfa <register> <offset>" instruction,
indicating the CFA register has changed to <register> with
the specified offset. */
cfi->dw_cfi_opc = DW_CFA_def_cfa;
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = loc.reg;
cfi->dw_cfi_oprnd2.dw_cfi_offset = loc.offset;
}
else
{
/* Construct a DW_CFA_def_cfa_expression instruction to
calculate the CFA using a full location expression since no
register-offset pair is available. */
struct dw_loc_descr_struct *loc_list;
cfi->dw_cfi_opc = DW_CFA_def_cfa_expression;
loc_list = build_cfa_loc (&loc);
cfi->dw_cfi_oprnd1.dw_cfi_loc = loc_list;
}
add_fde_cfi (label, cfi);
}
/* Add the CFI for saving a register. REG is the CFA column number.
LABEL is passed to add_fde_cfi.
If SREG is -1, the register is saved at OFFSET from the CFA;
otherwise it is saved in SREG. */
static void
reg_save (label, reg, sreg, offset)
const char *label;
unsigned reg;
unsigned sreg;
long offset;
{
dw_cfi_ref cfi = new_cfi ();
cfi->dw_cfi_oprnd1.dw_cfi_reg_num = reg;
/* The following comparison is correct. -1 is used to indicate that
the value isn't a register number. */
if (sreg == (unsigned int) -1)
{
if (reg & ~0x3f)
/* The register number won't fit in 6 bits, so we have to use
the long form. */
cfi->dw_cfi_opc = DW_CFA_offset_extended;
else
cfi->dw_cfi_opc = DW_CFA_offset;
#ifdef ENABLE_CHECKING
{
/* If we get an offset that is not a multiple of
DWARF_CIE_DATA_ALIGNMENT, there is either a bug in the
definition of DWARF_CIE_DATA_ALIGNMENT, or a bug in the machine
description. */
long check_offset = offset / DWARF_CIE_DATA_ALIGNMENT;
if (check_offset * DWARF_CIE_DATA_ALIGNMENT != offset)
abort ();
}
#endif
offset /= DWARF_CIE_DATA_ALIGNMENT;
if (offset < 0)
cfi->dw_cfi_opc = DW_CFA_offset_extended_sf;
cfi->dw_cfi_oprnd2.dw_cfi_offset = offset;
}
else if (sreg == reg)
/* We could emit a DW_CFA_same_value in this case, but don't bother. */
return;
else
{
cfi->dw_cfi_opc = DW_CFA_register;
cfi->dw_cfi_oprnd2.dw_cfi_reg_num = sreg;
}
add_fde_cfi (label, cfi);
}
/* Add the CFI for saving a register window. LABEL is passed to reg_save.
This CFI tells the unwinder that it needs to restore the window registers
from the previous frame's window save area.
??? Perhaps we should note in the CIE where windows are saved (instead of
assuming 0(cfa)) and what registers are in the window. */
void
dwarf2out_window_save (label)
const char *label;
{
dw_cfi_ref cfi = new_cfi ();
cfi->dw_cfi_opc = DW_CFA_GNU_window_save;
add_fde_cfi (label, cfi);
}
/* Add a CFI to update the running total of the size of arguments
pushed onto the stack. */
void
dwarf2out_args_size (label, size)
const char *label;
long size;
{
dw_cfi_ref cfi;
if (size == old_args_size)
return;
old_args_size = size;
cfi = new_cfi ();
cfi->dw_cfi_opc = DW_CFA_GNU_args_size;
cfi->dw_cfi_oprnd1.dw_cfi_offset = size;
add_fde_cfi (label, cfi);
}
/* Entry point for saving a register to the stack. REG is the GCC register
number. LABEL and OFFSET are passed to reg_save. */
void
dwarf2out_reg_save (label, reg, offset)
const char *label;
unsigned reg;
long offset;
{
reg_save (label, DWARF_FRAME_REGNUM (reg), -1, offset);
}
/* Entry point for saving the return address in the stack.
LABEL and OFFSET are passed to reg_save. */
void
dwarf2out_return_save (label, offset)
const char *label;
long offset;
{
reg_save (label, DWARF_FRAME_RETURN_COLUMN, -1, offset);
}
/* Entry point for saving the return address in a register.
LABEL and SREG are passed to reg_save. */
void
dwarf2out_return_reg (label, sreg)
const char *label;
unsigned sreg;
{
reg_save (label, DWARF_FRAME_RETURN_COLUMN, sreg, 0);
}
/* Record the initial position of the return address. RTL is
INCOMING_RETURN_ADDR_RTX. */
static void
initial_return_save (rtl)
rtx rtl;
{
unsigned int reg = (unsigned int) -1;
HOST_WIDE_INT offset = 0;
switch (GET_CODE (rtl))
{
case REG:
/* RA is in a register. */
reg = DWARF_FRAME_REGNUM (REGNO (rtl));
break;
case MEM:
/* RA is on the stack. */
rtl = XEXP (rtl, 0);
switch (GET_CODE (rtl))
{
case REG:
if (REGNO (rtl) != STACK_POINTER_REGNUM)
abort ();
offset = 0;
break;
case PLUS:
if (REGNO (XEXP (rtl, 0)) != STACK_POINTER_REGNUM)
abort ();
offset = INTVAL (XEXP (rtl, 1));
break;
case MINUS:
if (REGNO (XEXP (rtl, 0)) != STACK_POINTER_REGNUM)
abort ();
offset = -INTVAL (XEXP (rtl, 1));
break;
default:
abort ();
}
break;
case PLUS:
/* The return address is at some offset from any value we can
actually load. For instance, on the SPARC it is in %i7+8. Just
ignore the offset for now; it doesn't matter for unwinding frames. */
if (GET_CODE (XEXP (rtl, 1)) != CONST_INT)
abort ();
initial_return_save (XEXP (rtl, 0));
return;
default:
abort ();
}
reg_save (NULL, DWARF_FRAME_RETURN_COLUMN, reg, offset - cfa.offset);
}
/* Given a SET, calculate the amount of stack adjustment it
contains. */
static long
stack_adjust_offset (pattern)
rtx pattern;
{
rtx src = SET_SRC (pattern);
rtx dest = SET_DEST (pattern);
HOST_WIDE_INT offset = 0;
enum rtx_code code;
if (dest == stack_pointer_rtx)
{
/* (set (reg sp) (plus (reg sp) (const_int))) */
code = GET_CODE (src);
if (! (code == PLUS || code == MINUS)
|| XEXP (src, 0) != stack_pointer_rtx
|| GET_CODE (XEXP (src, 1)) != CONST_INT)
return 0;
offset = INTVAL (XEXP (src, 1));
if (code == PLUS)
offset = -offset;
}
else if (GET_CODE (dest) == MEM)
{
/* (set (mem (pre_dec (reg sp))) (foo)) */
src = XEXP (dest, 0);
code = GET_CODE (src);
switch (code)
{
case PRE_MODIFY:
case POST_MODIFY:
if (XEXP (src, 0) == stack_pointer_rtx)
{
rtx val = XEXP (XEXP (src, 1), 1);
/* We handle only adjustments by constant amount. */
if (GET_CODE (XEXP (src, 1)) != PLUS ||
GET_CODE (val) != CONST_INT)
abort ();
offset = -INTVAL (val);
break;
}
return 0;
case PRE_DEC:
case POST_DEC:
if (XEXP (src, 0) == stack_pointer_rtx)
{
offset = GET_MODE_SIZE (GET_MODE (dest));
break;
}
return 0;
case PRE_INC:
case POST_INC:
if (XEXP (src, 0) == stack_pointer_rtx)
{
offset = -GET_MODE_SIZE (GET_MODE (dest));
break;
}
return 0;
default:
return 0;
}
}
else
return 0;
return offset;
}
/* Check INSN to see if it looks like a push or a stack adjustment, and
make a note of it if it does. EH uses this information to find out how
much extra space it needs to pop off the stack. */
static void
dwarf2out_stack_adjust (insn)
rtx insn;
{
HOST_WIDE_INT offset;
const char *label;
int i;
if (!flag_asynchronous_unwind_tables && GET_CODE (insn) == CALL_INSN)
{
/* Extract the size of the args from the CALL rtx itself. */
insn = PATTERN (insn);
if (GET_CODE (insn) == PARALLEL)
insn = XVECEXP (insn, 0, 0);
if (GET_CODE (insn) == SET)
insn = SET_SRC (insn);
if (GET_CODE (insn) != CALL)
abort ();
dwarf2out_args_size ("", INTVAL (XEXP (insn, 1)));
return;
}
/* If only calls can throw, and we have a frame pointer,
save up adjustments until we see the CALL_INSN. */
else if (!flag_asynchronous_unwind_tables && cfa.reg != STACK_POINTER_REGNUM)
return;
if (GET_CODE (insn) == BARRIER)
{
/* When we see a BARRIER, we know to reset args_size to 0. Usually
the compiler will have already emitted a stack adjustment, but
doesn't bother for calls to noreturn functions. */
#ifdef STACK_GROWS_DOWNWARD
offset = -args_size;
#else
offset = args_size;
#endif
}
else if (GET_CODE (PATTERN (insn)) == SET)
offset = stack_adjust_offset (PATTERN (insn));
else if (GET_CODE (PATTERN (insn)) == PARALLEL
|| GET_CODE (PATTERN (insn)) == SEQUENCE)
{
/* There may be stack adjustments inside compound insns. Search
for them. */
for (offset = 0, i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
offset += stack_adjust_offset (XVECEXP (PATTERN (insn), 0, i));
}
else
return;
if (offset == 0)
return;
if (cfa.reg == STACK_POINTER_REGNUM)
cfa.offset += offset;
#ifndef STACK_GROWS_DOWNWARD
offset = -offset;
#endif
args_size += offset;
if (args_size < 0)
args_size = 0;
label = dwarf2out_cfi_label ();
def_cfa_1 (label, &cfa);
dwarf2out_args_size (label, args_size);
}
/* We delay emitting a register save until either (a) we reach the end
of the prologue or (b) the register is clobbered. This clusters
register saves so that there are fewer pc advances. */
struct queued_reg_save
{
struct queued_reg_save *next;
rtx reg;
long cfa_offset;
};
static struct queued_reg_save *queued_reg_saves;
static const char *last_reg_save_label;
static void
queue_reg_save (label, reg, offset)
const char *label;
rtx reg;
long offset;
{
struct queued_reg_save *q = (struct queued_reg_save *) xmalloc (sizeof (*q));
q->next = queued_reg_saves;
q->reg = reg;
q->cfa_offset = offset;
queued_reg_saves = q;
last_reg_save_label = label;
}
static void
flush_queued_reg_saves ()
{
struct queued_reg_save *q, *next;
for (q = queued_reg_saves; q; q = next)
{
dwarf2out_reg_save (last_reg_save_label, REGNO (q->reg), q->cfa_offset);
next = q->next;
free (q);
}
queued_reg_saves = NULL;
last_reg_save_label = NULL;
}
static bool
clobbers_queued_reg_save (insn)
rtx insn;
{
struct queued_reg_save *q;
for (q = queued_reg_saves; q; q = q->next)
if (modified_in_p (q->reg, insn))
return true;
return false;
}
/* A temporary register holding an integral value used in adjusting SP
or setting up the store_reg. The "offset" field holds the integer
value, not an offset. */
static dw_cfa_location cfa_temp;
/* Record call frame debugging information for an expression EXPR,
which either sets SP or FP (adjusting how we calculate the frame
address) or saves a register to the stack. LABEL indicates the
address of EXPR.
This function encodes a state machine mapping rtxes to actions on
cfa, cfa_store, and cfa_temp.reg. We describe these rules so
users need not read the source code.
The High-Level Picture
Changes in the register we use to calculate the CFA: Currently we
assume that if you copy the CFA register into another register, we
should take the other one as the new CFA register; this seems to
work pretty well. If it's wrong for some target, it's simple
enough not to set RTX_FRAME_RELATED_P on the insn in question.
Changes in the register we use for saving registers to the stack:
This is usually SP, but not always. Again, we deduce that if you
copy SP into another register (and SP is not the CFA register),
then the new register is the one we will be using for register
saves. This also seems to work.
Register saves: There's not much guesswork about this one; if
RTX_FRAME_RELATED_P is set on an insn which modifies memory, it's a
register save, and the register used to calculate the destination
had better be the one we think we're using for this purpose.
Except: If the register being saved is the CFA register, and the
offset is nonzero, we are saving the CFA, so we assume we have to
use DW_CFA_def_cfa_expression. If the offset is 0, we assume that
the intent is to save the value of SP from the previous frame.
Invariants / Summaries of Rules
cfa current rule for calculating the CFA. It usually
consists of a register and an offset.
cfa_store register used by prologue code to save things to the stack
cfa_store.offset is the offset from the value of
cfa_store.reg to the actual CFA
cfa_temp register holding an integral value. cfa_temp.offset
stores the value, which will be used to adjust the
stack pointer. cfa_temp is also used like cfa_store,
to track stores to the stack via fp or a temp reg.
Rules 1- 4: Setting a register's value to cfa.reg or an expression
with cfa.reg as the first operand changes the cfa.reg and its
cfa.offset. Rule 1 and 4 also set cfa_temp.reg and
cfa_temp.offset.
Rules 6- 9: Set a non-cfa.reg register value to a constant or an
expression yielding a constant. This sets cfa_temp.reg
and cfa_temp.offset.
Rule 5: Create a new register cfa_store used to save items to the
stack.
Rules 10-14: Save a register to the stack. Define offset as the
difference of the original location and cfa_store's
location (or cfa_temp's location if cfa_temp is used).
The Rules
"{a,b}" indicates a choice of a xor b.
"<reg>:cfa.reg" indicates that <reg> must equal cfa.reg.
Rule 1:
(set <reg1> <reg2>:cfa.reg)
effects: cfa.reg = <reg1>
cfa.offset unchanged
cfa_temp.reg = <reg1>
cfa_temp.offset = cfa.offset
Rule 2:
(set sp ({minus,plus,losum} {sp,fp}:cfa.reg
{<const_int>,<reg>:cfa_temp.reg}))
effects: cfa.reg = sp if fp used
cfa.offset += {+/- <const_int>, cfa_temp.offset} if cfa.reg==sp
cfa_store.offset += {+/- <const_int>, cfa_temp.offset}
if cfa_store.reg==sp
Rule 3:
(set fp ({minus,plus,losum} <reg>:cfa.reg <const_int>))
effects: cfa.reg = fp
cfa_offset += +/- <const_int>
Rule 4:
(set <reg1> ({plus,losum} <reg2>:cfa.reg <const_int>))
constraints: <reg1> != fp
<reg1> != sp
effects: cfa.reg = <reg1>
cfa_temp.reg = <reg1>
cfa_temp.offset = cfa.offset
Rule 5:
(set <reg1> (plus <reg2>:cfa_temp.reg sp:cfa.reg))
constraints: <reg1> != fp
<reg1> != sp
effects: cfa_store.reg = <reg1>
cfa_store.offset = cfa.offset - cfa_temp.offset
Rule 6:
(set <reg> <const_int>)
effects: cfa_temp.reg = <reg>
cfa_temp.offset = <const_int>
Rule 7:
(set <reg1>:cfa_temp.reg (ior <reg2>:cfa_temp.reg <const_int>))
effects: cfa_temp.reg = <reg1>
cfa_temp.offset |= <const_int>
Rule 8:
(set <reg> (high <exp>))
effects: none
Rule 9:
(set <reg> (lo_sum <exp> <const_int>))
effects: cfa_temp.reg = <reg>
cfa_temp.offset = <const_int>
Rule 10:
(set (mem (pre_modify sp:cfa_store (???? <reg1> <const_int>))) <reg2>)
effects: cfa_store.offset -= <const_int>
cfa.offset = cfa_store.offset if cfa.reg == sp
cfa.reg = sp
cfa.base_offset = -cfa_store.offset
Rule 11:
(set (mem ({pre_inc,pre_dec} sp:cfa_store.reg)) <reg>)
effects: cfa_store.offset += -/+ mode_size(mem)
cfa.offset = cfa_store.offset if cfa.reg == sp
cfa.reg = sp
cfa.base_offset = -cfa_store.offset
Rule 12:
(set (mem ({minus,plus,losum} <reg1>:{cfa_store,cfa_temp} <const_int>))
<reg2>)
effects: cfa.reg = <reg1>
cfa.base_offset = -/+ <const_int> - {cfa_store,cfa_temp}.offset
Rule 13:
(set (mem <reg1>:{cfa_store,cfa_temp}) <reg2>)
effects: cfa.reg = <reg1>
cfa.base_offset = -{cfa_store,cfa_temp}.offset
Rule 14:
(set (mem (postinc <reg1>:cfa_temp <const_int>)) <reg2>)
effects: cfa.reg = <reg1>
cfa.base_offset = -cfa_temp.offset
cfa_temp.offset -= mode_size(mem) */
static void
dwarf2out_frame_debug_expr (expr, label)
rtx expr;
const char *label;
{
rtx src, dest;
HOST_WIDE_INT offset;
/* If RTX_FRAME_RELATED_P is set on a PARALLEL, process each member of
the PARALLEL independently. The first element is always processed if
it is a SET. This is for backward compatibility. Other elements
are processed only if they are SETs and the RTX_FRAME_RELATED_P
flag is set in them. */
if (GET_CODE (expr) == PARALLEL || GET_CODE (expr) == SEQUENCE)
{
int par_index;
int limit = XVECLEN (expr, 0);
for (par_index = 0; par_index < limit; par_index++)
if (GET_CODE (XVECEXP (expr, 0, par_index)) == SET
&& (RTX_FRAME_RELATED_P (XVECEXP (expr, 0, par_index))
|| par_index == 0))
dwarf2out_frame_debug_expr (XVECEXP (expr, 0, par_index), label);
return;
}
if (GET_CODE (expr) != SET)
abort ();
src = SET_SRC (expr);
dest = SET_DEST (expr);
switch (GET_CODE (dest))
{
case REG:
/* Rule 1 */
/* Update the CFA rule wrt SP or FP. Make sure src is
relative to the current CFA register. */
switch (GET_CODE (src))
{
/* Setting FP from SP. */
case REG:
if (cfa.reg == (unsigned) REGNO (src))
/* OK. */
;
else
abort ();
/* We used to require that dest be either SP or FP, but the
ARM copies SP to a temporary register, and from there to
FP. So we just rely on the backends to only set
RTX_FRAME_RELATED_P on appropriate insns. */
cfa.reg = REGNO (dest);
cfa_temp.reg = cfa.reg;
cfa_temp.offset = cfa.offset;
break;
case PLUS:
case MINUS:
case LO_SUM:
if (dest == stack_pointer_rtx)
{
/* Rule 2 */
/* Adjusting SP. */
switch (GET_CODE (XEXP (src, 1)))
{
case CONST_INT:
offset = INTVAL (XEXP (src, 1));
break;
case REG:
if ((unsigned) REGNO (XEXP (src, 1)) != cfa_temp.reg)
abort ();
offset = cfa_temp.offset;
break;
default:
abort ();
}
if (XEXP (src, 0) == hard_frame_pointer_rtx)
{
/* Restoring SP from FP in the epilogue. */
if (cfa.reg != (unsigned) HARD_FRAME_POINTER_REGNUM)
abort ();
cfa.reg = STACK_POINTER_REGNUM;
}
else if (GET_CODE (src) == LO_SUM)
/* Assume we've set the source reg of the LO_SUM from sp. */
;
else if (XEXP (src, 0) != stack_pointer_rtx)
abort ();
if (GET_CODE (src) != MINUS)
offset = -offset;
if (cfa.reg == STACK_POINTER_REGNUM)
cfa.offset += offset;
if (cfa_store.reg == STACK_POINTER_REGNUM)
cfa_store.offset += offset;
}
else if (dest == hard_frame_pointer_rtx)
{
/* Rule 3 */
/* Either setting the FP from an offset of the SP,
or adjusting the FP */
if (! frame_pointer_needed)
abort ();
if (GET_CODE (XEXP (src, 0)) == REG
&& (unsigned) REGNO (XEXP (src, 0)) == cfa.reg
&& GET_CODE (XEXP (src, 1)) == CONST_INT)
{
offset = INTVAL (XEXP (src, 1));
if (GET_CODE (src) != MINUS)
offset = -offset;
cfa.offset += offset;
cfa.reg = HARD_FRAME_POINTER_REGNUM;
}
else
abort ();
}
else
{
if (GET_CODE (src) == MINUS)
abort ();
/* Rule 4 */
if (GET_CODE (XEXP (src, 0)) == REG
&& REGNO (XEXP (src, 0)) == cfa.reg
&& GET_CODE (XEXP (src, 1)) == CONST_INT)
{
/* Setting a temporary CFA register that will be copied
into the FP later on. */
offset = - INTVAL (XEXP (src, 1));
cfa.offset += offset;
cfa.reg = REGNO (dest);
/* Or used to save regs to the stack. */
cfa_temp.reg = cfa.reg;
cfa_temp.offset = cfa.offset;
}
/* Rule 5 */
else if (GET_CODE (XEXP (src, 0)) == REG
&& REGNO (XEXP (src, 0)) == cfa_temp.reg
&& XEXP (src, 1) == stack_pointer_rtx)
{
/* Setting a scratch register that we will use instead
of SP for saving registers to the stack. */
if (cfa.reg != STACK_POINTER_REGNUM)
abort ();
cfa_store.reg = REGNO (dest);
cfa_store.offset = cfa.offset - cfa_temp.offset;
}
/* Rule 9 */
else if (GET_CODE (src) == LO_SUM
&& GET_CODE (XEXP (src, 1)) == CONST_INT)
{
cfa_temp.reg = REGNO (dest);
cfa_temp.offset = INTVAL (XEXP (src, 1));
}
else
abort ();
}
break;
/* Rule 6 */
case CONST_INT:
cfa_temp.reg = REGNO (dest);
cfa_temp.offset = INTVAL (src);
break;
/* Rule 7 */
case IOR:
if (GET_CODE (XEXP (src, 0)) != REG
|| (unsigned) REGNO (XEXP (src, 0)) != cfa_temp.reg
|| GET_CODE (XEXP (src, 1)) != CONST_INT)
abort ();
if ((unsigned) REGNO (dest) != cfa_temp.reg)
cfa_temp.reg = REGNO (dest);
cfa_temp.offset |= INTVAL (XEXP (src, 1));
break;
/* Skip over HIGH, assuming it will be followed by a LO_SUM,
which will fill in all of the bits. */
/* Rule 8 */
case HIGH:
break;
default:
abort ();
}
def_cfa_1 (label, &cfa);
break;
case MEM:
if (GET_CODE (src) != REG)
abort ();
/* Saving a register to the stack. Make sure dest is relative to the
CFA register. */
switch (GET_CODE (XEXP (dest, 0)))
{
/* Rule 10 */
/* With a push. */
case PRE_MODIFY:
| 