/* Definitions for values of C expressions, for GDB.
- Copyright (C) 1986-2014 Free Software Foundation, Inc.
+ Copyright (C) 1986-2017 Free Software Foundation, Inc.
This file is part of GDB.
struct value_print_options;
struct xmethod_worker;
+/* Values can be partially 'optimized out' and/or 'unavailable'.
+ These are distinct states and have different string representations
+ and related error strings.
+
+ 'unavailable' has a specific meaning in this context. It means the
+ value exists in the program (at the machine level), but GDB has no
+ means to get to it. Such a value is normally printed as
+ <unavailable>. Examples of how to end up with an unavailable value
+ would be:
+
+ - We're inspecting a traceframe, and the memory or registers the
+ debug information says the value lives on haven't been collected.
+
+ - We're inspecting a core dump, the memory or registers the debug
+ information says the value lives aren't present in the dump
+ (that is, we have a partial/trimmed core dump, or we don't fully
+ understand/handle the core dump's format).
+
+ - We're doing live debugging, but the debug API has no means to
+ get at where the value lives in the machine, like e.g., ptrace
+ not having access to some register or register set.
+
+ - Any other similar scenario.
+
+ OTOH, "optimized out" is about what the compiler decided to generate
+ (or not generate). A chunk of a value that was optimized out does
+ not actually exist in the program. There's no way to get at it
+ short of compiling the program differently.
+
+ A register that has not been saved in a frame is likewise considered
+ optimized out, except not-saved registers have a different string
+ representation and related error strings. E.g., we'll print them as
+ <not-saved> instead of <optimized out>, as in:
+
+ (gdb) p/x $rax
+ $1 = <not saved>
+ (gdb) info registers rax
+ rax <not saved>
+
+ If the debug info describes a variable as being in such a register,
+ we'll still print the variable as <optimized out>. IOW, <not saved>
+ is reserved for inspecting registers at the machine level.
+
+ When comparing value contents, optimized out chunks, unavailable
+ chunks, and valid contents data are all considered different. See
+ value_contents_eq for more info.
+*/
+
/* The structure which defines the type of a value. It should never
be possible for a program lval value to survive over a call to the
inferior (i.e. to be put into the history list or an internal
put into the value history or exposed to Python are taken off this
list. */
-struct value *value_next (struct value *);
+struct value *value_next (const struct value *);
/* Type of the value. */
extern struct type *value_type (const struct value *);
+/* Return the gdbarch associated with the value. */
+
+extern struct gdbarch *get_value_arch (const struct value *value);
+
/* This is being used to change the type of an existing value, that
code should instead be creating a new value with the changed type
(but possibly shared content). */
/* Only used for bitfields; number of bits contained in them. */
-extern int value_bitsize (const struct value *);
-extern void set_value_bitsize (struct value *, int bit);
+extern LONGEST value_bitsize (const struct value *);
+extern void set_value_bitsize (struct value *, LONGEST bit);
/* Only used for bitfields; position of start of field. For
gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
-extern int value_bitpos (const struct value *);
-extern void set_value_bitpos (struct value *, int bit);
+extern LONGEST value_bitpos (const struct value *);
+extern void set_value_bitpos (struct value *, LONGEST bit);
/* Only used for bitfields; the containing value. This allows a
single read from the target when displaying multiple
bitfields. */
-struct value *value_parent (struct value *);
+struct value *value_parent (const struct value *);
extern void set_value_parent (struct value *value, struct value *parent);
/* Describes offset of a value within lval of a structure in bytes.
within the registers structure. Note also the member
embedded_offset below. */
-extern int value_offset (const struct value *);
-extern void set_value_offset (struct value *, int offset);
+extern LONGEST value_offset (const struct value *);
+extern void set_value_offset (struct value *, LONGEST offset);
/* The comment from "struct value" reads: ``Is it modifiable? Only
relevant if lval != not_lval.''. Shouldn't the value instead be
not_lval and be done with it? */
-extern int deprecated_value_modifiable (struct value *value);
+extern int deprecated_value_modifiable (const struct value *value);
/* If a value represents a C++ object, then the `type' field gives the
object's compile-time type. If the object actually belongs to some
`type', and `embedded_offset' is zero, so everything works
normally. */
-extern struct type *value_enclosing_type (struct value *);
+extern struct type *value_enclosing_type (const struct value *);
extern void set_value_enclosing_type (struct value *val,
struct type *new_type);
int resolve_simple_types,
int *real_type_found);
-extern int value_pointed_to_offset (struct value *value);
-extern void set_value_pointed_to_offset (struct value *value, int val);
-extern int value_embedded_offset (struct value *value);
-extern void set_value_embedded_offset (struct value *value, int val);
+extern LONGEST value_pointed_to_offset (const struct value *value);
+extern void set_value_pointed_to_offset (struct value *value, LONGEST val);
+extern LONGEST value_embedded_offset (const struct value *value);
+extern void set_value_embedded_offset (struct value *value, LONGEST val);
/* For lval_computed values, this structure holds functions used to
retrieve and set the value (or portions of the value).
TOVAL is not considered as an lvalue. */
void (*write) (struct value *toval, struct value *fromval);
- /* Check the validity of some bits in VALUE. This should return 1
- if all the bits starting at OFFSET and extending for LENGTH bits
- are valid, or 0 if any bit is invalid. */
- int (*check_validity) (const struct value *value, int offset, int length);
-
- /* Return 1 if any bit in VALUE is valid, 0 if they are all invalid. */
- int (*check_any_valid) (const struct value *value);
-
/* If non-NULL, this is used to implement pointer indirection for
this value. This method may return NULL, in which case value_ind
will fall back to ordinary indirection. */
/* If non-NULL, this is used to determine whether the indicated bits
of VALUE are a synthetic pointer. */
int (*check_synthetic_pointer) (const struct value *value,
- int offset, int length);
+ LONGEST offset, int length);
/* Return a duplicate of VALUE's closure, for use in a new value.
This may simply return the same closure, if VALUE's is
Otherwise, return 1. */
extern int valprint_check_validity (struct ui_file *stream, struct type *type,
- int embedded_offset,
+ LONGEST embedded_offset,
const struct value *val);
extern struct value *allocate_optimized_out_value (struct type *type);
element. If you ever change the way lazy flag is set and reset, be
sure to consider this use as well! */
-extern int value_lazy (struct value *);
+extern int value_lazy (const struct value *);
extern void set_value_lazy (struct value *value, int val);
-extern int value_stack (struct value *);
+extern int value_stack (const struct value *);
extern void set_value_stack (struct value *value, int val);
/* Throw an error complaining that the value has been optimized
extern const gdb_byte *
value_contents_for_printing_const (const struct value *value);
-extern int value_fetch_lazy (struct value *val);
+extern void value_fetch_lazy (struct value *val);
/* If nonzero, this is the value of a variable which does not actually
exist in the program, at least partially. If the value is lazy,
this may fetch it now. */
extern int value_optimized_out (struct value *value);
-extern void set_value_optimized_out (struct value *value, int val);
-/* Like value_optimized_out, but don't fetch the value even if it is
- lazy. Mainly useful for constructing other values using VALUE as
- template. */
-extern int value_optimized_out_const (const struct value *value);
+/* Given a value, return true if any of the contents bits starting at
+ OFFSET and extending for LENGTH bits is optimized out, false
+ otherwise. */
+
+extern int value_bits_any_optimized_out (const struct value *value,
+ int bit_offset, int bit_length);
-/* Like value_optimized_out, but return false if any bit in the object
- is valid. */
-extern int value_entirely_optimized_out (const struct value *value);
+/* Like value_optimized_out, but return true iff the whole value is
+ optimized out. */
+extern int value_entirely_optimized_out (struct value *value);
+
+/* Mark VALUE's content bytes starting at OFFSET and extending for
+ LENGTH bytes as optimized out. */
+
+extern void mark_value_bytes_optimized_out (struct value *value,
+ int offset, int length);
+
+/* Mark VALUE's content bits starting at OFFSET and extending for
+ LENGTH bits as optimized out. */
+
+extern void mark_value_bits_optimized_out (struct value *value,
+ LONGEST offset, LONGEST length);
/* Set or return field indicating whether a variable is initialized or
not, based on debugging information supplied by the compiler.
1 = initialized; 0 = uninitialized. */
-extern int value_initialized (struct value *);
+extern int value_initialized (const struct value *);
extern void set_value_initialized (struct value *, int);
/* Set COMPONENT's location as appropriate for a component of WHOLE
/* Like value_address, except the result does not include value's
offset. */
-extern CORE_ADDR value_raw_address (struct value *);
+extern CORE_ADDR value_raw_address (const struct value *);
/* Set the address of a value. */
extern void set_value_address (struct value *, CORE_ADDR);
extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
#define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
-/* Frame register value is relative to. This will be described in the
- lval enum above as "lval_register". */
-extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
-#define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
+/* Frame ID of "next" frame to which a register value is relative. A
+ register value is indicated by VALUE_LVAL being set to lval_register.
+ So, if the register value is found relative to frame F, then the
+ frame id of F->next will be stored in VALUE_NEXT_FRAME_ID. */
+extern struct frame_id *deprecated_value_next_frame_id_hack (struct value *);
+#define VALUE_NEXT_FRAME_ID(val) (*deprecated_value_next_frame_id_hack (val))
+
+/* Frame ID of frame to which a register value is relative. This is
+ similar to VALUE_NEXT_FRAME_ID, above, but may not be assigned to.
+ Note that VALUE_FRAME_ID effectively undoes the "next" operation
+ that was performed during the assignment to VALUE_NEXT_FRAME_ID. */
+#define VALUE_FRAME_ID(val) (get_prev_frame_id_by_id (VALUE_NEXT_FRAME_ID (val)))
/* Register number if the value is from a register. */
-extern short *deprecated_value_regnum_hack (struct value *);
+extern int *deprecated_value_regnum_hack (struct value *);
#define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
/* Return value after lval_funcs->coerce_ref (after check_typedef). Return
extern struct value * readjust_indirect_value_type (struct value *value,
struct type *enc_type,
- struct type *original_type,
- struct value *original_val);
+ const struct type *original_type,
+ const struct value *original_val);
/* Convert a REF to the object referenced. */
extern struct value *coerce_array (struct value *value);
-/* Given a value, determine whether the bits starting at OFFSET and
- extending for LENGTH bits are valid. This returns nonzero if all
- bits in the given range are valid, zero if any bit is invalid. */
-
-extern int value_bits_valid (const struct value *value,
- int offset, int length);
-
/* Given a value, determine whether the bits starting at OFFSET and
extending for LENGTH bits are a synthetic pointer. */
extern int value_bits_synthetic_pointer (const struct value *value,
- int offset, int length);
+ LONGEST offset, LONGEST length);
/* Given a value, determine whether the contents bytes starting at
OFFSET and extending for LENGTH bytes are available. This returns
byte is unavailable. */
extern int value_bytes_available (const struct value *value,
- int offset, int length);
+ LONGEST offset, LONGEST length);
/* Given a value, determine whether the contents bits starting at
OFFSET and extending for LENGTH bits are available. This returns
bit is unavailable. */
extern int value_bits_available (const struct value *value,
- int offset, int length);
+ LONGEST offset, LONGEST length);
/* Like value_bytes_available, but return false if any byte in the
whole object is unavailable. */
LENGTH bytes as unavailable. */
extern void mark_value_bytes_unavailable (struct value *value,
- int offset, int length);
+ LONGEST offset, LONGEST length);
/* Mark VALUE's content bits starting at OFFSET and extending for
LENGTH bits as unavailable. */
extern void mark_value_bits_unavailable (struct value *value,
- int offset, int length);
+ LONGEST offset, LONGEST length);
/* Compare LENGTH bytes of VAL1's contents starting at OFFSET1 with
LENGTH bytes of VAL2's contents starting at OFFSET2.
its enclosing type chunk, you'd do:
int len = TYPE_LENGTH (check_typedef (value_enclosing_type (val)));
- value_available_contents (val, 0, val, 0, len);
+ value_contents_eq (val, 0, val, 0, len);
+
+ Returns true iff the set of available/valid contents match.
+
+ Optimized-out contents are equal to optimized-out contents, and are
+ not equal to non-optimized-out contents.
- Returns true iff the set of available contents match. Unavailable
- contents compare equal with unavailable contents, and different
- with any available byte. For example, if 'x's represent an
- unavailable byte, and 'V' and 'Z' represent different available
- bytes, in a value with length 16:
+ Unavailable contente are equal to unavailable contents, and are not
+ equal to non-unavailable contents.
- offset: 0 4 8 12 16
- contents: xxxxVVVVxxxxVVZZ
+ For example, if 'x's represent an unavailable byte, and 'V' and 'Z'
+ represent different available/valid bytes, in a value with length
+ 16:
+
+ offset: 0 4 8 12 16
+ contents: xxxxVVVVxxxxVVZZ
then:
- value_available_contents_eq(val, 0, val, 8, 6) => 1
- value_available_contents_eq(val, 0, val, 4, 4) => 1
- value_available_contents_eq(val, 0, val, 8, 8) => 0
- value_available_contents_eq(val, 4, val, 12, 2) => 1
- value_available_contents_eq(val, 4, val, 12, 4) => 0
- value_available_contents_eq(val, 3, val, 4, 4) => 0
-
- We only know whether a value chunk is available if we've tried to
- read it. As this routine is used by printing routines, which may
- be printing values in the value history, long after the inferior is
- gone, it works with const values. Therefore, this routine must not
- be called with lazy values. */
-
-extern int value_available_contents_eq (const struct value *val1, int offset1,
- const struct value *val2, int offset2,
- int length);
-
-/* Read LENGTH bytes of memory starting at MEMADDR into BUFFER, which
- is (or will be copied to) VAL's contents buffer offset by
- EMBEDDED_OFFSET (that is, to &VAL->contents[EMBEDDED_OFFSET]).
- Marks value contents ranges as unavailable if the corresponding
- memory is likewise unavailable. STACK indicates whether the memory
- is known to be stack memory. */
-
-extern void read_value_memory (struct value *val, int embedded_offset,
+ value_contents_eq(val, 0, val, 8, 6) => 1
+ value_contents_eq(val, 0, val, 4, 4) => 0
+ value_contents_eq(val, 0, val, 8, 8) => 0
+ value_contents_eq(val, 4, val, 12, 2) => 1
+ value_contents_eq(val, 4, val, 12, 4) => 0
+ value_contents_eq(val, 3, val, 4, 4) => 0
+
+ If 'x's represent an unavailable byte, 'o' represents an optimized
+ out byte, in a value with length 8:
+
+ offset: 0 4 8
+ contents: xxxxoooo
+
+ then:
+
+ value_contents_eq(val, 0, val, 2, 2) => 1
+ value_contents_eq(val, 4, val, 6, 2) => 1
+ value_contents_eq(val, 0, val, 4, 4) => 0
+
+ We only know whether a value chunk is unavailable or optimized out
+ if we've tried to read it. As this routine is used by printing
+ routines, which may be printing values in the value history, long
+ after the inferior is gone, it works with const values. Therefore,
+ this routine must not be called with lazy values. */
+
+extern int value_contents_eq (const struct value *val1, LONGEST offset1,
+ const struct value *val2, LONGEST offset2,
+ LONGEST length);
+
+/* Read LENGTH addressable memory units starting at MEMADDR into BUFFER,
+ which is (or will be copied to) VAL's contents buffer offset by
+ BIT_OFFSET bits. Marks value contents ranges as unavailable if
+ the corresponding memory is likewise unavailable. STACK indicates
+ whether the memory is known to be stack memory. */
+
+extern void read_value_memory (struct value *val, LONGEST bit_offset,
int stack, CORE_ADDR memaddr,
gdb_byte *buffer, size_t length);
int *invp);
extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
-extern int unpack_value_bits_as_long (struct type *field_type,
- const gdb_byte *valaddr,
- int embedded_offset, int bitpos,
- int bitsize,
- const struct value *original_value,
- LONGEST *result);
-
extern LONGEST unpack_field_as_long (struct type *type,
const gdb_byte *valaddr,
int fieldno);
extern int unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
- int embedded_offset, int fieldno,
+ LONGEST embedded_offset, int fieldno,
const struct value *val, LONGEST *result);
+extern void unpack_value_bitfield (struct value *dest_val,
+ LONGEST bitpos, LONGEST bitsize,
+ const gdb_byte *valaddr,
+ LONGEST embedded_offset,
+ const struct value *val);
+
extern struct value *value_field_bitfield (struct type *type, int fieldno,
const gdb_byte *valaddr,
- int embedded_offset,
+ LONGEST embedded_offset,
const struct value *val);
extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
extern struct value *value_from_decfloat (struct type *type,
const gdb_byte *decbytes);
extern struct value *value_from_history_ref (const char *, const char **);
+extern struct value *value_from_component (struct value *, struct type *,
+ LONGEST);
extern struct value *value_at (struct type *type, CORE_ADDR addr);
extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
+/* Return the symbol's reading requirement. */
+
+extern enum symbol_needs_kind symbol_read_needs (struct symbol *);
+
+/* Return true if the symbol needs a frame. This is a wrapper for
+ symbol_read_needs that simply checks for SYMBOL_NEEDS_FRAME. */
+
extern int symbol_read_needs_frame (struct symbol *);
extern struct value *read_var_value (struct symbol *var,
+ const struct block *var_block,
struct frame_info *frame);
extern struct value *default_read_var_value (struct symbol *var,
+ const struct block *var_block,
struct frame_info *frame);
extern struct value *allocate_value (struct type *type);
extern struct value *allocate_value_lazy (struct type *type);
-extern void value_contents_copy (struct value *dst, int dst_offset,
- struct value *src, int src_offset,
- int length);
-extern void value_contents_copy_raw (struct value *dst, int dst_offset,
- struct value *src, int src_offset,
- int length);
+extern void value_contents_copy (struct value *dst, LONGEST dst_offset,
+ struct value *src, LONGEST src_offset,
+ LONGEST length);
+extern void value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
+ struct value *src, LONGEST src_offset,
+ LONGEST length);
extern struct value *allocate_repeat_value (struct type *type, int count);
extern struct value *value_mark (void);
-extern void value_free_to_mark (struct value *mark);
+extern void value_free_to_mark (const struct value *mark);
+
+/* A helper class that uses value_mark at construction time and calls
+ value_free_to_mark in the destructor. This is used to clear out
+ temporary values created during the lifetime of this object. */
+class scoped_value_mark
+{
+ public:
+
+ scoped_value_mark ()
+ : m_value (value_mark ())
+ {
+ }
+
+ ~scoped_value_mark ()
+ {
+ free_to_mark ();
+ }
+
+ scoped_value_mark (scoped_value_mark &&other) = default;
-extern struct value *value_cstring (char *ptr, ssize_t len,
+ DISABLE_COPY_AND_ASSIGN (scoped_value_mark);
+
+ /* Free the values currently on the value stack. */
+ void free_to_mark ()
+ {
+ if (m_value != NULL)
+ {
+ value_free_to_mark (m_value);
+ m_value = NULL;
+ }
+ }
+
+ private:
+
+ const struct value *m_value;
+};
+
+extern struct value *value_cstring (const char *ptr, ssize_t len,
struct type *char_type);
-extern struct value *value_string (char *ptr, ssize_t len,
+extern struct value *value_string (const char *ptr, ssize_t len,
struct type *char_type);
extern struct value *value_array (int lowbound, int highbound,
extern struct value *value_addr (struct value *arg1);
-extern struct value *value_ref (struct value *arg1);
+extern struct value *value_ref (struct value *arg1, enum type_code refcode);
extern struct value *value_assign (struct value *toval,
struct value *fromval);
enum oload_search_type method,
struct value **objp, struct symbol *fsym,
struct value **valp, struct symbol **symp,
- int *staticp, const int no_adl);
+ int *staticp, const int no_adl,
+ enum noside noside);
extern struct value *value_field (struct value *arg1, int fieldno);
-extern struct value *value_primitive_field (struct value *arg1, int offset,
+extern struct value *value_primitive_field (struct value *arg1, LONGEST offset,
int fieldno,
struct type *arg_type);
-extern struct type *value_rtti_indirect_type (struct value *, int *, int *,
+extern struct type *value_rtti_indirect_type (struct value *, int *, LONGEST *,
int *);
extern struct value *value_full_object (struct value *, struct type *, int,
extern void clear_internalvar (struct internalvar *var);
extern void set_internalvar_component (struct internalvar *var,
- int offset,
- int bitpos, int bitsize,
+ LONGEST offset,
+ LONGEST bitpos, LONGEST bitsize,
struct value *newvalue);
extern struct internalvar *lookup_only_internalvar (const char *name);
extern struct internalvar *create_internalvar (const char *name);
-extern VEC (char_ptr) *complete_internalvar (const char *name);
+extern void complete_internalvar (completion_tracker &tracker,
+ const char *name);
/* An internalvar can be dynamically computed by supplying a vector of
function pointers to perform various operations. */
enum noside noside);
extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
- int j, struct type *type, int offset);
+ int j, struct type *type, LONGEST offset);
extern int binop_types_user_defined_p (enum exp_opcode op,
struct type *type1,
extern void value_free (struct value *val);
+/* A free policy class to interface std::unique_ptr with
+ value_free. */
+
+struct value_deleter
+{
+ void operator() (struct value *value) const
+ {
+ value_free (value);
+ }
+};
+
+/* A unique pointer to a struct value. */
+
+typedef std::unique_ptr<struct value, value_deleter> gdb_value_up;
+
extern void free_all_values (void);
extern void free_value_chain (struct value *v);
extern int record_latest_value (struct value *val);
extern void modify_field (struct type *type, gdb_byte *addr,
- LONGEST fieldval, int bitpos, int bitsize);
+ LONGEST fieldval, LONGEST bitpos, LONGEST bitsize);
extern void type_print (struct type *type, const char *varstring,
struct ui_file *stream, int show);
-extern char *type_to_string (struct type *type);
+extern std::string type_to_string (struct type *type);
extern gdb_byte *baseclass_addr (struct type *type, int index,
gdb_byte *valaddr,
extern void print_floating (const gdb_byte *valaddr, struct type *type,
struct ui_file *stream);
-extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
- struct ui_file *stream);
-
extern void value_print (struct value *val, struct ui_file *stream,
const struct value_print_options *options);
struct ui_file *stream, int format,
enum val_prettyformat pretty);
-extern struct value *value_release_to_mark (struct value *mark);
+extern struct value *value_release_to_mark (const struct value *mark);
-extern void val_print (struct type *type, const gdb_byte *valaddr,
- int embedded_offset, CORE_ADDR address,
+extern void val_print (struct type *type,
+ LONGEST embedded_offset, CORE_ADDR address,
struct ui_file *stream, int recurse,
- const struct value *val,
+ struct value *val,
const struct value_print_options *options,
const struct language_defn *language);
extern void typedef_print (struct type *type, struct symbol *news,
struct ui_file *stream);
-extern char *internalvar_name (struct internalvar *var);
+extern char *internalvar_name (const struct internalvar *var);
extern void preserve_values (struct objfile *);
extern struct value *value_non_lval (struct value *);
+extern void value_force_lval (struct value *, CORE_ADDR);
+
+extern struct value *make_cv_value (int, int, struct value *);
+
extern void preserve_one_value (struct value *, struct objfile *, htab_t);
/* From valops.c */
extern struct value *value_of_xmethod (struct xmethod_worker *);
-struct value *call_xmethod (struct value *function,
- int argc, struct value **argv);
+extern struct type *result_type_of_xmethod (struct value *method,
+ int argc, struct value **argv);
+
+extern struct value *call_xmethod (struct value *method,
+ int argc, struct value **argv);
#endif /* !defined (VALUE_H) */