/* Low level packing and unpacking of values for GDB, the GNU Debugger.
- Copyright (C) 1986-2013 Free Software Foundation, Inc.
+ Copyright (C) 1986-2014 Free Software Foundation, Inc.
This file is part of GDB.
#include "defs.h"
#include "arch-utils.h"
-#include "gdb_string.h"
+#include <string.h>
#include "symtab.h"
#include "gdbtypes.h"
#include "value.h"
#include "valprint.h"
#include "cli/cli-decode.h"
#include "exceptions.h"
-#include "python/python.h"
+#include "extension.h"
#include <ctype.h>
#include "tracepoint.h"
#include "cp-abi.h"
reset, be sure to consider this use as well! */
unsigned int lazy : 1;
- /* If nonzero, this is the value of a variable which does not
- actually exist in the program. */
+ /* If nonzero, this is the value of a variable that does not
+ actually exist in the program. If nonzero, and LVAL is
+ lval_register, this is a register ($pc, $sp, etc., never a
+ program variable) that has not been saved in the frame. All
+ optimized-out values are treated pretty much the same, except
+ registers have a different string representation and related
+ error strings. */
unsigned int optimized_out : 1;
/* If value is a variable, is it initialized or not. */
/* If the value has been released. */
unsigned int released : 1;
+ /* Register number if the value is from a register. */
+ short regnum;
+
/* Location of value (if lval). */
union
{
taken off this list. */
struct value *next;
- /* Register number if the value is from a register. */
- short regnum;
-
/* Actual contents of the value. Target byte-order. NULL or not
valid if lazy is nonzero. */
gdb_byte *contents;
/* Unavailable ranges in CONTENTS. We mark unavailable ranges,
rather than available, since the common and default case is for a
- value to be available. This is filled in at value read time. */
+ value to be available. This is filled in at value read time. The
+ unavailable ranges are tracked in bits. */
VEC(range_s) *unavailable;
};
int
-value_bytes_available (const struct value *value, int offset, int length)
+value_bits_available (const struct value *value, int offset, int length)
{
gdb_assert (!value->lazy);
return !ranges_contain (value->unavailable, offset, length);
}
+int
+value_bytes_available (const struct value *value, int offset, int length)
+{
+ return value_bits_available (value,
+ offset * TARGET_CHAR_BIT,
+ length * TARGET_CHAR_BIT);
+}
+
int
value_entirely_available (struct value *value)
{
return 0;
}
+int
+value_entirely_unavailable (struct value *value)
+{
+ /* We can only tell whether the whole value is available when we try
+ to read it. */
+ if (value->lazy)
+ value_fetch_lazy (value);
+
+ if (VEC_length (range_s, value->unavailable) == 1)
+ {
+ struct range *t = VEC_index (range_s, value->unavailable, 0);
+
+ if (t->offset == 0
+ && t->length == (TARGET_CHAR_BIT
+ * TYPE_LENGTH (value_enclosing_type (value))))
+ return 1;
+ }
+
+ return 0;
+}
+
void
-mark_value_bytes_unavailable (struct value *value, int offset, int length)
+mark_value_bits_unavailable (struct value *value, int offset, int length)
{
range_s newr;
int i;
}
}
+void
+mark_value_bytes_unavailable (struct value *value, int offset, int length)
+{
+ mark_value_bits_unavailable (value,
+ offset * TARGET_CHAR_BIT,
+ length * TARGET_CHAR_BIT);
+}
+
/* Find the first range in RANGES that overlaps the range defined by
OFFSET and LENGTH, starting at element POS in the RANGES vector,
Returns the index into RANGES where such overlapping range was
return -1;
}
-int
-value_available_contents_eq (const struct value *val1, int offset1,
- const struct value *val2, int offset2,
- int length)
+/* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
+ PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
+ return non-zero.
+
+ It must always be the case that:
+ OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
+
+ It is assumed that memory can be accessed from:
+ PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
+ to:
+ PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
+ / TARGET_CHAR_BIT) */
+static int
+memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
+ const gdb_byte *ptr2, size_t offset2_bits,
+ size_t length_bits)
+{
+ gdb_assert (offset1_bits % TARGET_CHAR_BIT
+ == offset2_bits % TARGET_CHAR_BIT);
+
+ if (offset1_bits % TARGET_CHAR_BIT != 0)
+ {
+ size_t bits;
+ gdb_byte mask, b1, b2;
+
+ /* The offset from the base pointers PTR1 and PTR2 is not a complete
+ number of bytes. A number of bits up to either the next exact
+ byte boundary, or LENGTH_BITS (which ever is sooner) will be
+ compared. */
+ bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
+ gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
+ mask = (1 << bits) - 1;
+
+ if (length_bits < bits)
+ {
+ mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
+ bits = length_bits;
+ }
+
+ /* Now load the two bytes and mask off the bits we care about. */
+ b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
+ b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
+
+ if (b1 != b2)
+ return 1;
+
+ /* Now update the length and offsets to take account of the bits
+ we've just compared. */
+ length_bits -= bits;
+ offset1_bits += bits;
+ offset2_bits += bits;
+ }
+
+ if (length_bits % TARGET_CHAR_BIT != 0)
+ {
+ size_t bits;
+ size_t o1, o2;
+ gdb_byte mask, b1, b2;
+
+ /* The length is not an exact number of bytes. After the previous
+ IF.. block then the offsets are byte aligned, or the
+ length is zero (in which case this code is not reached). Compare
+ a number of bits at the end of the region, starting from an exact
+ byte boundary. */
+ bits = length_bits % TARGET_CHAR_BIT;
+ o1 = offset1_bits + length_bits - bits;
+ o2 = offset2_bits + length_bits - bits;
+
+ gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
+ mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
+
+ gdb_assert (o1 % TARGET_CHAR_BIT == 0);
+ gdb_assert (o2 % TARGET_CHAR_BIT == 0);
+
+ b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
+ b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
+
+ if (b1 != b2)
+ return 1;
+
+ length_bits -= bits;
+ }
+
+ if (length_bits > 0)
+ {
+ /* We've now taken care of any stray "bits" at the start, or end of
+ the region to compare, the remainder can be covered with a simple
+ memcmp. */
+ gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
+ gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
+ gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
+
+ return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
+ ptr2 + offset2_bits / TARGET_CHAR_BIT,
+ length_bits / TARGET_CHAR_BIT);
+ }
+
+ /* Length is zero, regions match. */
+ return 0;
+}
+
+/* Helper function for value_available_contents_eq. The only difference is
+ that this function is bit rather than byte based.
+
+ Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits with
+ LENGTH bits of VAL2's contents starting at OFFSET2 bits. Return true
+ if the available bits match. */
+
+static int
+value_available_contents_bits_eq (const struct value *val1, int offset1,
+ const struct value *val2, int offset2,
+ int length)
{
int idx1 = 0, idx2 = 0;
/* The usual case is for both values to be completely available. */
if (idx1 == -1 && idx2 == -1)
- return (memcmp (val1->contents + offset1,
- val2->contents + offset2,
- length) == 0);
+ return (memcmp_with_bit_offsets (val1->contents, offset1,
+ val2->contents, offset2,
+ length) == 0);
/* The contents only match equal if the available set matches as
well. */
else if (idx1 == -1 || idx2 == -1)
return 0;
/* Compare the _available_ contents. */
- if (memcmp (val1->contents + offset1,
- val2->contents + offset2,
- l1) != 0)
+ if (memcmp_with_bit_offsets (val1->contents, offset1,
+ val2->contents, offset2, l1) != 0)
return 0;
length -= h1;
return 1;
}
+int
+value_available_contents_eq (const struct value *val1, int offset1,
+ const struct value *val2, int offset2,
+ int length)
+{
+ return value_available_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
+ val2, offset2 * TARGET_CHAR_BIT,
+ length * TARGET_CHAR_BIT);
+}
+
/* Prototypes for local functions. */
static void show_values (char *, int);
/* Allocate the contents of VAL if it has not been allocated yet. */
-void
+static void
allocate_value_contents (struct value *val)
{
if (!val->contents)
struct value *retval = allocate_value_lazy (type);
set_value_optimized_out (retval, 1);
-
+ set_value_lazy (retval, 0);
return retval;
}
return result;
}
+void
+error_value_optimized_out (void)
+{
+ error (_("value has been optimized out"));
+}
+
static void
require_not_optimized_out (const struct value *value)
{
if (value->optimized_out)
- error (_("value has been optimized out"));
+ {
+ if (value->lval == lval_register)
+ error (_("register has not been saved in frame"));
+ else
+ error_value_optimized_out ();
+ }
}
static void
{
range_s *r;
int i;
+ int src_bit_offset, dst_bit_offset, bit_length;
/* A lazy DST would make that this copy operation useless, since as
soon as DST's contents were un-lazied (by a later value_contents
length);
/* Copy the meta-data, adjusted. */
+ src_bit_offset = src_offset * TARGET_CHAR_BIT;
+ dst_bit_offset = dst_offset * TARGET_CHAR_BIT;
+ bit_length = length * TARGET_CHAR_BIT;
for (i = 0; VEC_iterate (range_s, src->unavailable, i, r); i++)
{
ULONGEST h, l;
- l = max (r->offset, src_offset);
- h = min (r->offset + r->length, src_offset + length);
+ l = max (r->offset, src_bit_offset);
+ h = min (r->offset + r->length, src_bit_offset + bit_length);
if (l < h)
- mark_value_bytes_unavailable (dst,
- dst_offset + (l - src_offset),
- h - l);
+ mark_value_bits_unavailable (dst,
+ dst_bit_offset + (l - src_bit_offset),
+ h - l);
}
}
/* Access to the value history. */
/* Record a new value in the value history.
- Returns the absolute history index of the entry.
- Result of -1 indicates the value was not saved; otherwise it is the
- value history index of this new item. */
+ Returns the absolute history index of the entry. */
int
record_latest_value (struct value *val)
for (var = internalvars; var; var = var->next)
preserve_one_internalvar (var, objfile, copied_types);
- preserve_python_values (objfile, copied_types);
+ preserve_ext_lang_values (objfile, copied_types);
htab_delete (copied_types);
}
\f
/* Get the value of the FIELDNO'th field (which must be static) of
- TYPE. Return NULL if the field doesn't exist or has been
- optimized out. */
+ TYPE. */
struct value *
value_static_field (struct type *type, int fieldno)
{
/* With some compilers, e.g. HP aCC, static data members are
reported as non-debuggable symbols. */
- struct minimal_symbol *msym = lookup_minimal_symbol (phys_name,
- NULL, NULL);
+ struct bound_minimal_symbol msym
+ = lookup_minimal_symbol (phys_name, NULL, NULL);
- if (!msym)
- return NULL;
+ if (!msym.minsym)
+ return allocate_optimized_out_value (type);
else
{
retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
- SYMBOL_VALUE_ADDRESS (msym));
+ BMSYMBOL_VALUE_ADDRESS (msym));
}
}
else
struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
struct symbol *sym;
- struct minimal_symbol *msym;
+ struct bound_minimal_symbol msym;
sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0);
if (sym != NULL)
{
- msym = NULL;
+ memset (&msym, 0, sizeof (msym));
}
else
{
gdb_assert (sym == NULL);
- msym = lookup_minimal_symbol (physname, NULL, NULL);
- if (msym == NULL)
+ msym = lookup_bound_minimal_symbol (physname);
+ if (msym.minsym == NULL)
return NULL;
}
{
/* The minimal symbol might point to a function descriptor;
resolve it to the actual code address instead. */
- struct objfile *objfile = msymbol_objfile (msym);
+ struct objfile *objfile = msym.objfile;
struct gdbarch *gdbarch = get_objfile_arch (objfile);
set_value_address (v,
gdbarch_convert_from_func_ptr_addr
- (gdbarch, SYMBOL_VALUE_ADDRESS (msym), ¤t_target));
+ (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), ¤t_target));
}
if (arg1p)
read_offset = bitpos / 8;
if (original_value != NULL
- && !value_bytes_available (original_value, embedded_offset + read_offset,
- bytes_read))
+ && !value_bits_available (original_value, embedded_offset + bitpos,
+ bitsize))
return 0;
val = extract_unsigned_integer (valaddr + embedded_offset + read_offset,
if (valaddr == NULL)
v = allocate_value_lazy (type);
else
- {
- v = allocate_value (type);
- memcpy (value_contents_raw (v), valaddr, TYPE_LENGTH (type));
- }
+ v = value_from_contents (type, valaddr);
set_value_address (v, address);
VALUE_LVAL (v) = lval_memory;
return v;
if (!value_bits_valid (parent,
TARGET_CHAR_BIT * offset + value_bitpos (val),
value_bitsize (val)))
- error (_("value has been optimized out"));
-
- if (!unpack_value_bits_as_long (value_type (val),
+ set_value_optimized_out (val, 1);
+ else if (!unpack_value_bits_as_long (value_type (val),
value_contents_for_printing (parent),
offset,
value_bitpos (val),
while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
{
- frame = frame_find_by_id (VALUE_FRAME_ID (new_val));
+ struct frame_id frame_id = VALUE_FRAME_ID (new_val);
+
+ frame = frame_find_by_id (frame_id);
regnum = VALUE_REGNUM (new_val);
gdb_assert (frame != NULL);
regnum, type));
new_val = get_frame_register_value (frame, regnum);
+
+ /* If we get another lazy lval_register value, it means the
+ register is found by reading it from the next frame.
+ get_frame_register_value should never return a value with
+ the frame id pointing to FRAME. If it does, it means we
+ either have two consecutive frames with the same frame id
+ in the frame chain, or some code is trying to unwind
+ behind get_prev_frame's back (e.g., a frame unwind
+ sniffer trying to unwind), bypassing its validations. In
+ any case, it should always be an internal error to end up
+ in this situation. */
+ if (VALUE_LVAL (new_val) == lval_register
+ && value_lazy (new_val)
+ && frame_id_eq (VALUE_FRAME_ID (new_val), frame_id))
+ internal_error (__FILE__, __LINE__,
+ _("infinite loop while fetching a register"));
}
/* If it's still lazy (for instance, a saved register on the
fprintf_unfiltered (gdb_stdlog, "->");
if (value_optimized_out (new_val))
- fprintf_unfiltered (gdb_stdlog, " optimized out");
+ {
+ fprintf_unfiltered (gdb_stdlog, " ");
+ val_print_optimized_out (new_val, gdb_stdlog);
+ }
else
{
int i;
return 0;
}
+/* Implementation of the convenience function $_isvoid. */
+
+static struct value *
+isvoid_internal_fn (struct gdbarch *gdbarch,
+ const struct language_defn *language,
+ void *cookie, int argc, struct value **argv)
+{
+ int ret;
+
+ if (argc != 1)
+ error (_("You must provide one argument for $_isvoid."));
+
+ ret = TYPE_CODE (value_type (argv[0])) == TYPE_CODE_VOID;
+
+ return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
+}
+
void
_initialize_values (void)
{
add_prefix_cmd ("function", no_class, function_command, _("\
Placeholder command for showing help on convenience functions."),
&functionlist, "function ", 0, &cmdlist);
+
+ add_internal_function ("_isvoid", _("\
+Check whether an expression is void.\n\
+Usage: $_isvoid (expression)\n\
+Return 1 if the expression is void, zero otherwise."),
+ isvoid_internal_fn, NULL);
}
projects / binutils-gdb.git / blobdiff