| /* Low level packing and unpacking of values for GDB, the GNU Debugger. |
| |
| Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, |
| 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003 Free Software |
| Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program 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 of the License, or |
| (at your option) any later version. |
| |
| This program 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 this program; if not, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| #include "gdb_string.h" |
| #include "symtab.h" |
| #include "gdbtypes.h" |
| #include "value.h" |
| #include "gdbcore.h" |
| #include "command.h" |
| #include "gdbcmd.h" |
| #include "target.h" |
| #include "language.h" |
| #include "scm-lang.h" |
| #include "demangle.h" |
| #include "doublest.h" |
| #include "gdb_assert.h" |
| #include "regcache.h" |
| #include "block.h" |
| |
| /* Prototypes for exported functions. */ |
| |
| void _initialize_values (void); |
| |
| /* Prototypes for local functions. */ |
| |
| static void show_values (char *, int); |
| |
| static void show_convenience (char *, int); |
| |
| |
| /* The value-history records all the values printed |
| by print commands during this session. Each chunk |
| records 60 consecutive values. The first chunk on |
| the chain records the most recent values. |
| The total number of values is in value_history_count. */ |
| |
| #define VALUE_HISTORY_CHUNK 60 |
| |
| struct value_history_chunk |
| { |
| struct value_history_chunk *next; |
| struct value *values[VALUE_HISTORY_CHUNK]; |
| }; |
| |
| /* Chain of chunks now in use. */ |
| |
| static struct value_history_chunk *value_history_chain; |
| |
| static int value_history_count; /* Abs number of last entry stored */ |
| |
| /* List of all value objects currently allocated |
| (except for those released by calls to release_value) |
| This is so they can be freed after each command. */ |
| |
| static struct value *all_values; |
| |
| /* Allocate a value that has the correct length for type TYPE. */ |
| |
| struct value * |
| allocate_value (struct type *type) |
| { |
| struct value *val; |
| struct type *atype = check_typedef (type); |
| |
| val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype)); |
| VALUE_NEXT (val) = all_values; |
| all_values = val; |
| VALUE_TYPE (val) = type; |
| VALUE_ENCLOSING_TYPE (val) = type; |
| VALUE_LVAL (val) = not_lval; |
| VALUE_ADDRESS (val) = 0; |
| VALUE_FRAME_ID (val) = null_frame_id; |
| VALUE_OFFSET (val) = 0; |
| VALUE_BITPOS (val) = 0; |
| VALUE_BITSIZE (val) = 0; |
| VALUE_REGNO (val) = -1; |
| VALUE_LAZY (val) = 0; |
| VALUE_OPTIMIZED_OUT (val) = 0; |
| VALUE_BFD_SECTION (val) = NULL; |
| VALUE_EMBEDDED_OFFSET (val) = 0; |
| VALUE_POINTED_TO_OFFSET (val) = 0; |
| val->modifiable = 1; |
| return val; |
| } |
| |
| /* Allocate a value that has the correct length |
| for COUNT repetitions type TYPE. */ |
| |
| struct value * |
| allocate_repeat_value (struct type *type, int count) |
| { |
| int low_bound = current_language->string_lower_bound; /* ??? */ |
| /* FIXME-type-allocation: need a way to free this type when we are |
| done with it. */ |
| struct type *range_type |
| = create_range_type ((struct type *) NULL, builtin_type_int, |
| low_bound, count + low_bound - 1); |
| /* FIXME-type-allocation: need a way to free this type when we are |
| done with it. */ |
| return allocate_value (create_array_type ((struct type *) NULL, |
| type, range_type)); |
| } |
| |
| /* Return a mark in the value chain. All values allocated after the |
| mark is obtained (except for those released) are subject to being freed |
| if a subsequent value_free_to_mark is passed the mark. */ |
| struct value * |
| value_mark (void) |
| { |
| return all_values; |
| } |
| |
| /* Free all values allocated since MARK was obtained by value_mark |
| (except for those released). */ |
| void |
| value_free_to_mark (struct value *mark) |
| { |
| struct value *val; |
| struct value *next; |
| |
| for (val = all_values; val && val != mark; val = next) |
| { |
| next = VALUE_NEXT (val); |
| value_free (val); |
| } |
| all_values = val; |
| } |
| |
| /* Free all the values that have been allocated (except for those released). |
| Called after each command, successful or not. */ |
| |
| void |
| free_all_values (void) |
| { |
| struct value *val; |
| struct value *next; |
| |
| for (val = all_values; val; val = next) |
| { |
| next = VALUE_NEXT (val); |
| value_free (val); |
| } |
| |
| all_values = 0; |
| } |
| |
| /* Remove VAL from the chain all_values |
| so it will not be freed automatically. */ |
| |
| void |
| release_value (struct value *val) |
| { |
| struct value *v; |
| |
| if (all_values == val) |
| { |
| all_values = val->next; |
| return; |
| } |
| |
| for (v = all_values; v; v = v->next) |
| { |
| if (v->next == val) |
| { |
| v->next = val->next; |
| break; |
| } |
| } |
| } |
| |
| /* Release all values up to mark */ |
| struct value * |
| value_release_to_mark (struct value *mark) |
| { |
| struct value *val; |
| struct value *next; |
| |
| for (val = next = all_values; next; next = VALUE_NEXT (next)) |
| if (VALUE_NEXT (next) == mark) |
| { |
| all_values = VALUE_NEXT (next); |
| VALUE_NEXT (next) = 0; |
| return val; |
| } |
| all_values = 0; |
| return val; |
| } |
| |
| /* Return a copy of the value ARG. |
| It contains the same contents, for same memory address, |
| but it's a different block of storage. */ |
| |
| struct value * |
| value_copy (struct value *arg) |
| { |
| register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg); |
| struct value *val = allocate_value (encl_type); |
| VALUE_TYPE (val) = VALUE_TYPE (arg); |
| VALUE_LVAL (val) = VALUE_LVAL (arg); |
| VALUE_ADDRESS (val) = VALUE_ADDRESS (arg); |
| VALUE_OFFSET (val) = VALUE_OFFSET (arg); |
| VALUE_BITPOS (val) = VALUE_BITPOS (arg); |
| VALUE_BITSIZE (val) = VALUE_BITSIZE (arg); |
| VALUE_FRAME_ID (val) = VALUE_FRAME_ID (arg); |
| VALUE_REGNO (val) = VALUE_REGNO (arg); |
| VALUE_LAZY (val) = VALUE_LAZY (arg); |
| VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg); |
| VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg); |
| VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg); |
| VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg); |
| val->modifiable = arg->modifiable; |
| if (!VALUE_LAZY (val)) |
| { |
| memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg), |
| TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg))); |
| |
| } |
| return val; |
| } |
| |
| /* 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. */ |
| |
| int |
| record_latest_value (struct value *val) |
| { |
| int i; |
| |
| /* We don't want this value to have anything to do with the inferior anymore. |
| In particular, "set $1 = 50" should not affect the variable from which |
| the value was taken, and fast watchpoints should be able to assume that |
| a value on the value history never changes. */ |
| if (VALUE_LAZY (val)) |
| value_fetch_lazy (val); |
| /* We preserve VALUE_LVAL so that the user can find out where it was fetched |
| from. This is a bit dubious, because then *&$1 does not just return $1 |
| but the current contents of that location. c'est la vie... */ |
| val->modifiable = 0; |
| release_value (val); |
| |
| /* Here we treat value_history_count as origin-zero |
| and applying to the value being stored now. */ |
| |
| i = value_history_count % VALUE_HISTORY_CHUNK; |
| if (i == 0) |
| { |
| struct value_history_chunk *new |
| = (struct value_history_chunk *) |
| xmalloc (sizeof (struct value_history_chunk)); |
| memset (new->values, 0, sizeof new->values); |
| new->next = value_history_chain; |
| value_history_chain = new; |
| } |
| |
| value_history_chain->values[i] = val; |
| |
| /* Now we regard value_history_count as origin-one |
| and applying to the value just stored. */ |
| |
| return ++value_history_count; |
| } |
| |
| /* Return a copy of the value in the history with sequence number NUM. */ |
| |
| struct value * |
| access_value_history (int num) |
| { |
| struct value_history_chunk *chunk; |
| register int i; |
| register int absnum = num; |
| |
| if (absnum <= 0) |
| absnum += value_history_count; |
| |
| if (absnum <= 0) |
| { |
| if (num == 0) |
| error ("The history is empty."); |
| else if (num == 1) |
| error ("There is only one value in the history."); |
| else |
| error ("History does not go back to $$%d.", -num); |
| } |
| if (absnum > value_history_count) |
| error ("History has not yet reached $%d.", absnum); |
| |
| absnum--; |
| |
| /* Now absnum is always absolute and origin zero. */ |
| |
| chunk = value_history_chain; |
| for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; |
| i > 0; i--) |
| chunk = chunk->next; |
| |
| return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); |
| } |
| |
| /* Clear the value history entirely. |
| Must be done when new symbol tables are loaded, |
| because the type pointers become invalid. */ |
| |
| void |
| clear_value_history (void) |
| { |
| struct value_history_chunk *next; |
| register int i; |
| struct value *val; |
| |
| while (value_history_chain) |
| { |
| for (i = 0; i < VALUE_HISTORY_CHUNK; i++) |
| if ((val = value_history_chain->values[i]) != NULL) |
| xfree (val); |
| next = value_history_chain->next; |
| xfree (value_history_chain); |
| value_history_chain = next; |
| } |
| value_history_count = 0; |
| } |
| |
| static void |
| show_values (char *num_exp, int from_tty) |
| { |
| register int i; |
| struct value *val; |
| static int num = 1; |
| |
| if (num_exp) |
| { |
| /* "info history +" should print from the stored position. |
| "info history <exp>" should print around value number <exp>. */ |
| if (num_exp[0] != '+' || num_exp[1] != '\0') |
| num = parse_and_eval_long (num_exp) - 5; |
| } |
| else |
| { |
| /* "info history" means print the last 10 values. */ |
| num = value_history_count - 9; |
| } |
| |
| if (num <= 0) |
| num = 1; |
| |
| for (i = num; i < num + 10 && i <= value_history_count; i++) |
| { |
| val = access_value_history (i); |
| printf_filtered ("$%d = ", i); |
| value_print (val, gdb_stdout, 0, Val_pretty_default); |
| printf_filtered ("\n"); |
| } |
| |
| /* The next "info history +" should start after what we just printed. */ |
| num += 10; |
| |
| /* Hitting just return after this command should do the same thing as |
| "info history +". If num_exp is null, this is unnecessary, since |
| "info history +" is not useful after "info history". */ |
| if (from_tty && num_exp) |
| { |
| num_exp[0] = '+'; |
| num_exp[1] = '\0'; |
| } |
| } |
| |
| /* Internal variables. These are variables within the debugger |
| that hold values assigned by debugger commands. |
| The user refers to them with a '$' prefix |
| that does not appear in the variable names stored internally. */ |
| |
| static struct internalvar *internalvars; |
| |
| /* Look up an internal variable with name NAME. NAME should not |
| normally include a dollar sign. |
| |
| If the specified internal variable does not exist, |
| one is created, with a void value. */ |
| |
| struct internalvar * |
| lookup_internalvar (char *name) |
| { |
| register struct internalvar *var; |
| |
| for (var = internalvars; var; var = var->next) |
| if (strcmp (var->name, name) == 0) |
| return var; |
| |
| var = (struct internalvar *) xmalloc (sizeof (struct internalvar)); |
| var->name = concat (name, NULL); |
| var->value = allocate_value (builtin_type_void); |
| release_value (var->value); |
| var->next = internalvars; |
| internalvars = var; |
| return var; |
| } |
| |
| struct value * |
| value_of_internalvar (struct internalvar *var) |
| { |
| struct value *val; |
| |
| val = value_copy (var->value); |
| if (VALUE_LAZY (val)) |
| value_fetch_lazy (val); |
| VALUE_LVAL (val) = lval_internalvar; |
| VALUE_INTERNALVAR (val) = var; |
| return val; |
| } |
| |
| void |
| set_internalvar_component (struct internalvar *var, int offset, int bitpos, |
| int bitsize, struct value *newval) |
| { |
| register char *addr = VALUE_CONTENTS (var->value) + offset; |
| |
| if (bitsize) |
| modify_field (addr, value_as_long (newval), |
| bitpos, bitsize); |
| else |
| memcpy (addr, VALUE_CONTENTS (newval), TYPE_LENGTH (VALUE_TYPE (newval))); |
| } |
| |
| void |
| set_internalvar (struct internalvar *var, struct value *val) |
| { |
| struct value *newval; |
| |
| newval = value_copy (val); |
| newval->modifiable = 1; |
| |
| /* Force the value to be fetched from the target now, to avoid problems |
| later when this internalvar is referenced and the target is gone or |
| has changed. */ |
| if (VALUE_LAZY (newval)) |
| value_fetch_lazy (newval); |
| |
| /* Begin code which must not call error(). If var->value points to |
| something free'd, an error() obviously leaves a dangling pointer. |
| But we also get a danling pointer if var->value points to |
| something in the value chain (i.e., before release_value is |
| called), because after the error free_all_values will get called before |
| long. */ |
| xfree (var->value); |
| var->value = newval; |
| release_value (newval); |
| /* End code which must not call error(). */ |
| } |
| |
| char * |
| internalvar_name (struct internalvar *var) |
| { |
| return var->name; |
| } |
| |
| /* Free all internalvars. Done when new symtabs are loaded, |
| because that makes the values invalid. */ |
| |
| void |
| clear_internalvars (void) |
| { |
| register struct internalvar *var; |
| |
| while (internalvars) |
| { |
| var = internalvars; |
| internalvars = var->next; |
| xfree (var->name); |
| xfree (var->value); |
| xfree (var); |
| } |
| } |
| |
| static void |
| show_convenience (char *ignore, int from_tty) |
| { |
| register struct internalvar *var; |
| int varseen = 0; |
| |
| for (var = internalvars; var; var = var->next) |
| { |
| if (!varseen) |
| { |
| varseen = 1; |
| } |
| printf_filtered ("$%s = ", var->name); |
| value_print (var->value, gdb_stdout, 0, Val_pretty_default); |
| printf_filtered ("\n"); |
| } |
| if (!varseen) |
| printf_unfiltered ("No debugger convenience variables now defined.\n\ |
| Convenience variables have names starting with \"$\";\n\ |
| use \"set\" as in \"set $foo = 5\" to define them.\n"); |
| } |
| |
| /* Extract a value as a C number (either long or double). |
| Knows how to convert fixed values to double, or |
| floating values to long. |
| Does not deallocate the value. */ |
| |
| LONGEST |
| value_as_long (struct value *val) |
| { |
| /* This coerces arrays and functions, which is necessary (e.g. |
| in disassemble_command). It also dereferences references, which |
| I suspect is the most logical thing to do. */ |
| COERCE_ARRAY (val); |
| return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| } |
| |
| DOUBLEST |
| value_as_double (struct value *val) |
| { |
| DOUBLEST foo; |
| int inv; |
| |
| foo = unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &inv); |
| if (inv) |
| error ("Invalid floating value found in program."); |
| return foo; |
| } |
| /* Extract a value as a C pointer. Does not deallocate the value. |
| Note that val's type may not actually be a pointer; value_as_long |
| handles all the cases. */ |
| CORE_ADDR |
| value_as_address (struct value *val) |
| { |
| /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| whether we want this to be true eventually. */ |
| #if 0 |
| /* ADDR_BITS_REMOVE is wrong if we are being called for a |
| non-address (e.g. argument to "signal", "info break", etc.), or |
| for pointers to char, in which the low bits *are* significant. */ |
| return ADDR_BITS_REMOVE (value_as_long (val)); |
| #else |
| |
| /* There are several targets (IA-64, PowerPC, and others) which |
| don't represent pointers to functions as simply the address of |
| the function's entry point. For example, on the IA-64, a |
| function pointer points to a two-word descriptor, generated by |
| the linker, which contains the function's entry point, and the |
| value the IA-64 "global pointer" register should have --- to |
| support position-independent code. The linker generates |
| descriptors only for those functions whose addresses are taken. |
| |
| On such targets, it's difficult for GDB to convert an arbitrary |
| function address into a function pointer; it has to either find |
| an existing descriptor for that function, or call malloc and |
| build its own. On some targets, it is impossible for GDB to |
| build a descriptor at all: the descriptor must contain a jump |
| instruction; data memory cannot be executed; and code memory |
| cannot be modified. |
| |
| Upon entry to this function, if VAL is a value of type `function' |
| (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then |
| VALUE_ADDRESS (val) is the address of the function. This is what |
| you'll get if you evaluate an expression like `main'. The call |
| to COERCE_ARRAY below actually does all the usual unary |
| conversions, which includes converting values of type `function' |
| to `pointer to function'. This is the challenging conversion |
| discussed above. Then, `unpack_long' will convert that pointer |
| back into an address. |
| |
| So, suppose the user types `disassemble foo' on an architecture |
| with a strange function pointer representation, on which GDB |
| cannot build its own descriptors, and suppose further that `foo' |
| has no linker-built descriptor. The address->pointer conversion |
| will signal an error and prevent the command from running, even |
| though the next step would have been to convert the pointer |
| directly back into the same address. |
| |
| The following shortcut avoids this whole mess. If VAL is a |
| function, just return its address directly. */ |
| if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC |
| || TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_METHOD) |
| return VALUE_ADDRESS (val); |
| |
| COERCE_ARRAY (val); |
| |
| /* Some architectures (e.g. Harvard), map instruction and data |
| addresses onto a single large unified address space. For |
| instance: An architecture may consider a large integer in the |
| range 0x10000000 .. 0x1000ffff to already represent a data |
| addresses (hence not need a pointer to address conversion) while |
| a small integer would still need to be converted integer to |
| pointer to address. Just assume such architectures handle all |
| integer conversions in a single function. */ |
| |
| /* JimB writes: |
| |
| I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we |
| must admonish GDB hackers to make sure its behavior matches the |
| compiler's, whenever possible. |
| |
| In general, I think GDB should evaluate expressions the same way |
| the compiler does. When the user copies an expression out of |
| their source code and hands it to a `print' command, they should |
| get the same value the compiler would have computed. Any |
| deviation from this rule can cause major confusion and annoyance, |
| and needs to be justified carefully. In other words, GDB doesn't |
| really have the freedom to do these conversions in clever and |
| useful ways. |
| |
| AndrewC pointed out that users aren't complaining about how GDB |
| casts integers to pointers; they are complaining that they can't |
| take an address from a disassembly listing and give it to `x/i'. |
| This is certainly important. |
| |
| Adding an architecture method like INTEGER_TO_ADDRESS certainly |
| makes it possible for GDB to "get it right" in all circumstances |
| --- the target has complete control over how things get done, so |
| people can Do The Right Thing for their target without breaking |
| anyone else. The standard doesn't specify how integers get |
| converted to pointers; usually, the ABI doesn't either, but |
| ABI-specific code is a more reasonable place to handle it. */ |
| |
| if (TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_PTR |
| && TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_REF |
| && INTEGER_TO_ADDRESS_P ()) |
| return INTEGER_TO_ADDRESS (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| |
| return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| #endif |
| } |
| |
| /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| as a long, or as a double, assuming the raw data is described |
| by type TYPE. Knows how to convert different sizes of values |
| and can convert between fixed and floating point. We don't assume |
| any alignment for the raw data. Return value is in host byte order. |
| |
| If you want functions and arrays to be coerced to pointers, and |
| references to be dereferenced, call value_as_long() instead. |
| |
| C++: It is assumed that the front-end has taken care of |
| all matters concerning pointers to members. A pointer |
| to member which reaches here is considered to be equivalent |
| to an INT (or some size). After all, it is only an offset. */ |
| |
| LONGEST |
| unpack_long (struct type *type, const char *valaddr) |
| { |
| register enum type_code code = TYPE_CODE (type); |
| register int len = TYPE_LENGTH (type); |
| register int nosign = TYPE_UNSIGNED (type); |
| |
| if (current_language->la_language == language_scm |
| && is_scmvalue_type (type)) |
| return scm_unpack (type, valaddr, TYPE_CODE_INT); |
| |
| switch (code) |
| { |
| case TYPE_CODE_TYPEDEF: |
| return unpack_long (check_typedef (type), valaddr); |
| case TYPE_CODE_ENUM: |
| case TYPE_CODE_BOOL: |
| case TYPE_CODE_INT: |
| case TYPE_CODE_CHAR: |
| case TYPE_CODE_RANGE: |
| if (nosign) |
| return extract_unsigned_integer (valaddr, len); |
| else |
| return extract_signed_integer (valaddr, len); |
| |
| case TYPE_CODE_FLT: |
| return extract_typed_floating (valaddr, type); |
| |
| case TYPE_CODE_PTR: |
| case TYPE_CODE_REF: |
| /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| whether we want this to be true eventually. */ |
| return extract_typed_address (valaddr, type); |
| |
| case TYPE_CODE_MEMBER: |
| error ("not implemented: member types in unpack_long"); |
| |
| default: |
| error ("Value can't be converted to integer."); |
| } |
| return 0; /* Placate lint. */ |
| } |
| |
| /* Return a double value from the specified type and address. |
| INVP points to an int which is set to 0 for valid value, |
| 1 for invalid value (bad float format). In either case, |
| the returned double is OK to use. Argument is in target |
| format, result is in host format. */ |
| |
| DOUBLEST |
| unpack_double (struct type *type, const char *valaddr, int *invp) |
| { |
| enum type_code code; |
| int len; |
| int nosign; |
| |
| *invp = 0; /* Assume valid. */ |
| CHECK_TYPEDEF (type); |
| code = TYPE_CODE (type); |
| len = TYPE_LENGTH (type); |
| nosign = TYPE_UNSIGNED (type); |
| if (code == TYPE_CODE_FLT) |
| { |
| /* NOTE: cagney/2002-02-19: There was a test here to see if the |
| floating-point value was valid (using the macro |
| INVALID_FLOAT). That test/macro have been removed. |
| |
| It turns out that only the VAX defined this macro and then |
| only in a non-portable way. Fixing the portability problem |
| wouldn't help since the VAX floating-point code is also badly |
| bit-rotten. The target needs to add definitions for the |
| methods TARGET_FLOAT_FORMAT and TARGET_DOUBLE_FORMAT - these |
| exactly describe the target floating-point format. The |
| problem here is that the corresponding floatformat_vax_f and |
| floatformat_vax_d values these methods should be set to are |
| also not defined either. Oops! |
| |
| Hopefully someone will add both the missing floatformat |
| definitions and floatformat_is_invalid() function. */ |
| return extract_typed_floating (valaddr, type); |
| } |
| else if (nosign) |
| { |
| /* Unsigned -- be sure we compensate for signed LONGEST. */ |
| return (ULONGEST) unpack_long (type, valaddr); |
| } |
| else |
| { |
| /* Signed -- we are OK with unpack_long. */ |
| return unpack_long (type, valaddr); |
| } |
| } |
| |
| /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| as a CORE_ADDR, assuming the raw data is described by type TYPE. |
| We don't assume any alignment for the raw data. Return value is in |
| host byte order. |
| |
| If you want functions and arrays to be coerced to pointers, and |
| references to be dereferenced, call value_as_address() instead. |
| |
| C++: It is assumed that the front-end has taken care of |
| all matters concerning pointers to members. A pointer |
| to member which reaches here is considered to be equivalent |
| to an INT (or some size). After all, it is only an offset. */ |
| |
| CORE_ADDR |
| unpack_pointer (struct type *type, const char *valaddr) |
| { |
| /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| whether we want this to be true eventually. */ |
| return unpack_long (type, valaddr); |
| } |
| |
| |
| /* Get the value of the FIELDN'th field (which must be static) of |
| TYPE. Return NULL if the field doesn't exist or has been |
| optimized out. */ |
| |
| struct value * |
| value_static_field (struct type *type, int fieldno) |
| { |
| struct value *retval; |
| |
| if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno)) |
| { |
| retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
| TYPE_FIELD_STATIC_PHYSADDR (type, fieldno), |
| NULL); |
| } |
| else |
| { |
| char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno); |
| struct symbol *sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0, NULL); |
| if (sym == NULL) |
| { |
| /* 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); |
| if (!msym) |
| return NULL; |
| else |
| { |
| retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
| SYMBOL_VALUE_ADDRESS (msym), |
| SYMBOL_BFD_SECTION (msym)); |
| } |
| } |
| else |
| { |
| /* SYM should never have a SYMBOL_CLASS which will require |
| read_var_value to use the FRAME parameter. */ |
| if (symbol_read_needs_frame (sym)) |
| warning ("static field's value depends on the current " |
| "frame - bad debug info?"); |
| retval = read_var_value (sym, NULL); |
| } |
| if (retval && VALUE_LVAL (retval) == lval_memory) |
| SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), |
| VALUE_ADDRESS (retval)); |
| } |
| return retval; |
| } |
| |
| /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE. |
| You have to be careful here, since the size of the data area for the value |
| is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger |
| than the old enclosing type, you have to allocate more space for the data. |
| The return value is a pointer to the new version of this value structure. */ |
| |
| struct value * |
| value_change_enclosing_type (struct value *val, struct type *new_encl_type) |
| { |
| if (TYPE_LENGTH (new_encl_type) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val))) |
| { |
| VALUE_ENCLOSING_TYPE (val) = new_encl_type; |
| return val; |
| } |
| else |
| { |
| struct value *new_val; |
| struct value *prev; |
| |
| new_val = (struct value *) xrealloc (val, sizeof (struct value) + TYPE_LENGTH (new_encl_type)); |
| |
| VALUE_ENCLOSING_TYPE (new_val) = new_encl_type; |
| |
| /* We have to make sure this ends up in the same place in the value |
| chain as the original copy, so it's clean-up behavior is the same. |
| If the value has been released, this is a waste of time, but there |
| is no way to tell that in advance, so... */ |
| |
| if (val != all_values) |
| { |
| for (prev = all_values; prev != NULL; prev = prev->next) |
| { |
| if (prev->next == val) |
| { |
| prev->next = new_val; |
| break; |
| } |
| } |
| } |
| |
| return new_val; |
| } |
| } |
| |
| /* Given a value ARG1 (offset by OFFSET bytes) |
| of a struct or union type ARG_TYPE, |
| extract and return the value of one of its (non-static) fields. |
| FIELDNO says which field. */ |
| |
| struct value * |
| value_primitive_field (struct value *arg1, int offset, |
| register int fieldno, register struct type *arg_type) |
| { |
| struct value *v; |
| register struct type *type; |
| |
| CHECK_TYPEDEF (arg_type); |
| type = TYPE_FIELD_TYPE (arg_type, fieldno); |
| |
| /* Handle packed fields */ |
| |
| if (TYPE_FIELD_BITSIZE (arg_type, fieldno)) |
| { |
| v = value_from_longest (type, |
| unpack_field_as_long (arg_type, |
| VALUE_CONTENTS (arg1) |
| + offset, |
| fieldno)); |
| VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8; |
| VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno); |
| VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| } |
| else if (fieldno < TYPE_N_BASECLASSES (arg_type)) |
| { |
| /* This field is actually a base subobject, so preserve the |
| entire object's contents for later references to virtual |
| bases, etc. */ |
| v = allocate_value (VALUE_ENCLOSING_TYPE (arg1)); |
| VALUE_TYPE (v) = type; |
| if (VALUE_LAZY (arg1)) |
| VALUE_LAZY (v) = 1; |
| else |
| memcpy (VALUE_CONTENTS_ALL_RAW (v), VALUE_CONTENTS_ALL_RAW (arg1), |
| TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1))); |
| VALUE_OFFSET (v) = VALUE_OFFSET (arg1); |
| VALUE_EMBEDDED_OFFSET (v) |
| = offset + |
| VALUE_EMBEDDED_OFFSET (arg1) + |
| TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| } |
| else |
| { |
| /* Plain old data member */ |
| offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| v = allocate_value (type); |
| if (VALUE_LAZY (arg1)) |
| VALUE_LAZY (v) = 1; |
| else |
| memcpy (VALUE_CONTENTS_RAW (v), |
| VALUE_CONTENTS_RAW (arg1) + offset, |
| TYPE_LENGTH (type)); |
| VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| + VALUE_EMBEDDED_OFFSET (arg1); |
| } |
| VALUE_LVAL (v) = VALUE_LVAL (arg1); |
| if (VALUE_LVAL (arg1) == lval_internalvar) |
| VALUE_LVAL (v) = lval_internalvar_component; |
| VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1); |
| VALUE_REGNO (v) = VALUE_REGNO (arg1); |
| /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */ |
| return v; |
| } |
| |
| /* Given a value ARG1 of a struct or union type, |
| extract and return the value of one of its (non-static) fields. |
| FIELDNO says which field. */ |
| |
| struct value * |
| value_field (struct value *arg1, register int fieldno) |
| { |
| return value_primitive_field (arg1, 0, fieldno, VALUE_TYPE (arg1)); |
| } |
| |
| /* Return a non-virtual function as a value. |
| F is the list of member functions which contains the desired method. |
| J is an index into F which provides the desired method. |
| |
| We only use the symbol for its address, so be happy with either a |
| full symbol or a minimal symbol. |
| */ |
| |
| struct value * |
| value_fn_field (struct value **arg1p, struct fn_field *f, int j, struct type *type, |
| int offset) |
| { |
| struct value *v; |
| register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); |
| char *physname = TYPE_FN_FIELD_PHYSNAME (f, j); |
| struct symbol *sym; |
| struct minimal_symbol *msym; |
| |
| sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0, NULL); |
| if (sym != NULL) |
| { |
| msym = NULL; |
| } |
| else |
| { |
| gdb_assert (sym == NULL); |
| msym = lookup_minimal_symbol (physname, NULL, NULL); |
| if (msym == NULL) |
| return NULL; |
| } |
| |
| v = allocate_value (ftype); |
| if (sym) |
| { |
| VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); |
| } |
| else |
| { |
| VALUE_ADDRESS (v) = SYMBOL_VALUE_ADDRESS (msym); |
| } |
| |
| if (arg1p) |
| { |
| if (type != VALUE_TYPE (*arg1p)) |
| *arg1p = value_ind (value_cast (lookup_pointer_type (type), |
| value_addr (*arg1p))); |
| |
| /* Move the `this' pointer according to the offset. |
| VALUE_OFFSET (*arg1p) += offset; |
| */ |
| } |
| |
| return v; |
| } |
| |
| |
| /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at |
| VALADDR. |
| |
| Extracting bits depends on endianness of the machine. Compute the |
| number of least significant bits to discard. For big endian machines, |
| we compute the total number of bits in the anonymous object, subtract |
| off the bit count from the MSB of the object to the MSB of the |
| bitfield, then the size of the bitfield, which leaves the LSB discard |
| count. For little endian machines, the discard count is simply the |
| number of bits from the LSB of the anonymous object to the LSB of the |
| bitfield. |
| |
| If the field is signed, we also do sign extension. */ |
| |
| LONGEST |
| unpack_field_as_long (struct type *type, const char *valaddr, int fieldno) |
| { |
| ULONGEST val; |
| ULONGEST valmask; |
| int bitpos = TYPE_FIELD_BITPOS (type, fieldno); |
| int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); |
| int lsbcount; |
| struct type *field_type; |
| |
| val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val)); |
| field_type = TYPE_FIELD_TYPE (type, fieldno); |
| CHECK_TYPEDEF (field_type); |
| |
| /* Extract bits. See comment above. */ |
| |
| if (BITS_BIG_ENDIAN) |
| lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize); |
| else |
| lsbcount = (bitpos % 8); |
| val >>= lsbcount; |
| |
| /* If the field does not entirely fill a LONGEST, then zero the sign bits. |
| If the field is signed, and is negative, then sign extend. */ |
| |
| if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val))) |
| { |
| valmask = (((ULONGEST) 1) << bitsize) - 1; |
| val &= valmask; |
| if (!TYPE_UNSIGNED (field_type)) |
| { |
| if (val & (valmask ^ (valmask >> 1))) |
| { |
| val |= ~valmask; |
| } |
| } |
| } |
| return (val); |
| } |
| |
| /* Modify the value of a bitfield. ADDR points to a block of memory in |
| target byte order; the bitfield starts in the byte pointed to. FIELDVAL |
| is the desired value of the field, in host byte order. BITPOS and BITSIZE |
| indicate which bits (in target bit order) comprise the bitfield. */ |
| |
| void |
| modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize) |
| { |
| LONGEST oword; |
| |
| /* If a negative fieldval fits in the field in question, chop |
| off the sign extension bits. */ |
| if (bitsize < (8 * (int) sizeof (fieldval)) |
| && (~fieldval & ~((1 << (bitsize - 1)) - 1)) == 0) |
| fieldval = fieldval & ((1 << bitsize) - 1); |
| |
| /* Warn if value is too big to fit in the field in question. */ |
| if (bitsize < (8 * (int) sizeof (fieldval)) |
| && 0 != (fieldval & ~((1 << bitsize) - 1))) |
| { |
| /* FIXME: would like to include fieldval in the message, but |
| we don't have a sprintf_longest. */ |
| warning ("Value does not fit in %d bits.", bitsize); |
| |
| /* Truncate it, otherwise adjoining fields may be corrupted. */ |
| fieldval = fieldval & ((1 << bitsize) - 1); |
| } |
| |
| oword = extract_signed_integer (addr, sizeof oword); |
| |
| /* Shifting for bit field depends on endianness of the target machine. */ |
| if (BITS_BIG_ENDIAN) |
| bitpos = sizeof (oword) * 8 - bitpos - bitsize; |
| |
| /* Mask out old value, while avoiding shifts >= size of oword */ |
| if (bitsize < 8 * (int) sizeof (oword)) |
| oword &= ~(((((ULONGEST) 1) << bitsize) - 1) << bitpos); |
| else |
| oword &= ~((~(ULONGEST) 0) << bitpos); |
| oword |= fieldval << bitpos; |
| |
| store_signed_integer (addr, sizeof oword, oword); |
| } |
| |
| /* Convert C numbers into newly allocated values */ |
| |
| struct value * |
| value_from_longest (struct type *type, register LONGEST num) |
| { |
| struct value *val = allocate_value (type); |
| register enum type_code code; |
| register int len; |
| retry: |
| code = TYPE_CODE (type); |
| len = TYPE_LENGTH (type); |
| |
| switch (code) |
| { |
| case TYPE_CODE_TYPEDEF: |
| type = check_typedef (type); |
| goto retry; |
| case TYPE_CODE_INT: |
| case TYPE_CODE_CHAR: |
| case TYPE_CODE_ENUM: |
| case TYPE_CODE_BOOL: |
| case TYPE_CODE_RANGE: |
| store_signed_integer (VALUE_CONTENTS_RAW (val), len, num); |
| break; |
| |
| case TYPE_CODE_REF: |
| case TYPE_CODE_PTR: |
| store_typed_address (VALUE_CONTENTS_RAW (val), type, (CORE_ADDR) num); |
| break; |
| |
| default: |
| error ("Unexpected type (%d) encountered for integer constant.", code); |
| } |
| return val; |
| } |
| |
| |
| /* Create a value representing a pointer of type TYPE to the address |
| ADDR. */ |
| struct value * |
| value_from_pointer (struct type *type, CORE_ADDR addr) |
| { |
| struct value *val = allocate_value (type); |
| store_typed_address (VALUE_CONTENTS_RAW (val), type, addr); |
| return val; |
| } |
| |
| |
| /* Create a value for a string constant to be stored locally |
| (not in the inferior's memory space, but in GDB memory). |
| This is analogous to value_from_longest, which also does not |
| use inferior memory. String shall NOT contain embedded nulls. */ |
| |
| struct value * |
| value_from_string (char *ptr) |
| { |
| struct value *val; |
| int len = strlen (ptr); |
| int lowbound = current_language->string_lower_bound; |
| struct type *rangetype = |
| create_range_type ((struct type *) NULL, |
| builtin_type_int, |
| lowbound, len + lowbound - 1); |
| struct type *stringtype = |
| create_array_type ((struct type *) NULL, |
| *current_language->string_char_type, |
| rangetype); |
| |
| val = allocate_value (stringtype); |
| memcpy (VALUE_CONTENTS_RAW (val), ptr, len); |
| return val; |
| } |
| |
| struct value * |
| value_from_double (struct type *type, DOUBLEST num) |
| { |
| struct value *val = allocate_value (type); |
| struct type *base_type = check_typedef (type); |
| register enum type_code code = TYPE_CODE (base_type); |
| register int len = TYPE_LENGTH (base_type); |
| |
| if (code == TYPE_CODE_FLT) |
| { |
| store_typed_floating (VALUE_CONTENTS_RAW (val), base_type, num); |
| } |
| else |
| error ("Unexpected type encountered for floating constant."); |
| |
| return val; |
| } |
| |
| /* Deal with the value that is "about to be returned". */ |
| |
| /* Return the value that a function returning now |
| would be returning to its caller, assuming its type is VALTYPE. |
| RETBUF is where we look for what ought to be the contents |
| of the registers (in raw form). This is because it is often |
| desirable to restore old values to those registers |
| after saving the contents of interest, and then call |
| this function using the saved values. |
| struct_return is non-zero when the function in question is |
| using the structure return conventions on the machine in question; |
| 0 when it is using the value returning conventions (this often |
| means returning pointer to where structure is vs. returning value). */ |
| |
| /* ARGSUSED */ |
| struct value * |
| value_being_returned (struct type *valtype, struct regcache *retbuf, |
| int struct_return) |
| { |
| struct value *val; |
| CORE_ADDR addr; |
| |
| /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */ |
| if (EXTRACT_STRUCT_VALUE_ADDRESS_P ()) |
| if (struct_return) |
| { |
| addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf); |
| if (!addr) |
| error ("Function return value unknown."); |
| return value_at (valtype, addr, NULL); |
| } |
| |
| /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */ |
| if (DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS_P ()) |
| if (struct_return) |
| { |
| char *buf = deprecated_grub_regcache_for_registers (retbuf); |
| addr = DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS (buf); |
| if (!addr) |
| error ("Function return value unknown."); |
| return value_at (valtype, addr, NULL); |
| } |
| |
| val = allocate_value (valtype); |
| CHECK_TYPEDEF (valtype); |
| /* If the function returns void, don't bother fetching the return value. */ |
| if (TYPE_CODE (valtype) != TYPE_CODE_VOID) |
| EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val)); |
| |
| return val; |
| } |
| |
| /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of |
| EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc |
| and TYPE is the type (which is known to be struct, union or array). |
| |
| On most machines, the struct convention is used unless we are |
| using gcc and the type is of a special size. */ |
| /* As of about 31 Mar 93, GCC was changed to be compatible with the |
| native compiler. GCC 2.3.3 was the last release that did it the |
| old way. Since gcc2_compiled was not changed, we have no |
| way to correctly win in all cases, so we just do the right thing |
| for gcc1 and for gcc2 after this change. Thus it loses for gcc |
| 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled |
| would cause more chaos than dealing with some struct returns being |
| handled wrong. */ |
| |
| int |
| generic_use_struct_convention (int gcc_p, struct type *value_type) |
| { |
| return !((gcc_p == 1) |
| && (TYPE_LENGTH (value_type) == 1 |
| || TYPE_LENGTH (value_type) == 2 |
| || TYPE_LENGTH (value_type) == 4 |
| || TYPE_LENGTH (value_type) == 8)); |
| } |
| |
| /* Return true if the function specified is using the structure returning |
| convention on this machine to return arguments, or 0 if it is using |
| the value returning convention. FUNCTION is the value representing |
| the function, FUNCADDR is the address of the function, and VALUE_TYPE |
| is the type returned by the function. GCC_P is nonzero if compiled |
| with GCC. */ |
| |
| /* ARGSUSED */ |
| int |
| using_struct_return (struct value *function, CORE_ADDR funcaddr, |
| struct type *value_type, int gcc_p) |
| { |
| register enum type_code code = TYPE_CODE (value_type); |
| |
| if (code == TYPE_CODE_ERROR) |
| error ("Function return type unknown."); |
| |
| if (code == TYPE_CODE_STRUCT |
| || code == TYPE_CODE_UNION |
| || code == TYPE_CODE_ARRAY |
| || RETURN_VALUE_ON_STACK (value_type)) |
| return USE_STRUCT_CONVENTION (gcc_p, value_type); |
| |
| return 0; |
| } |
| |
| /* Store VAL so it will be returned if a function returns now. |
| Does not verify that VAL's type matches what the current |
| function wants to return. */ |
| |
| void |
| set_return_value (struct value *val) |
| { |
| struct type *type = check_typedef (VALUE_TYPE (val)); |
| register enum type_code code = TYPE_CODE (type); |
| |
| if (code == TYPE_CODE_ERROR) |
| error ("Function return type unknown."); |
| |
| if (code == TYPE_CODE_STRUCT |
| || code == TYPE_CODE_UNION) /* FIXME, implement struct return. */ |
| error ("GDB does not support specifying a struct or union return value."); |
| |
| STORE_RETURN_VALUE (type, current_regcache, VALUE_CONTENTS (val)); |
| } |
| |
| void |
| _initialize_values (void) |
| { |
| add_cmd ("convenience", no_class, show_convenience, |
| "Debugger convenience (\"$foo\") variables.\n\ |
| These variables are created when you assign them values;\n\ |
| thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\ |
| A few convenience variables are given values automatically:\n\ |
| \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\ |
| \"$__\" holds the contents of the last address examined with \"x\".", |
| &showlist); |
| |
| add_cmd ("values", no_class, show_values, |
| "Elements of value history around item number IDX (or last ten).", |
| &showlist); |
| } |