/* Low level packing and unpacking of values for GDB, the GNU Debugger. Copyright 1986, 1987, 1989, 1991 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., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "defs.h" #include #include "symtab.h" #include "gdbtypes.h" #include "value.h" #include "gdbcore.h" #include "frame.h" #include "command.h" #include "gdbcmd.h" #include "target.h" #include "demangle.h" /* Local function prototypes. */ static value value_headof PARAMS ((value, struct type *, struct type *)); static void show_values PARAMS ((char *, int)); static void show_convenience PARAMS ((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; 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 value all_values; /* Allocate a value that has the correct length for type TYPE. */ value allocate_value (type) struct type *type; { register value val; check_stub_type (type); val = (value) xmalloc (sizeof (struct value) + TYPE_LENGTH (type)); VALUE_NEXT (val) = all_values; all_values = val; VALUE_TYPE (val) = type; VALUE_LVAL (val) = not_lval; VALUE_ADDRESS (val) = 0; VALUE_FRAME (val) = 0; VALUE_OFFSET (val) = 0; VALUE_BITPOS (val) = 0; VALUE_BITSIZE (val) = 0; VALUE_REPEATED (val) = 0; VALUE_REPETITIONS (val) = 0; VALUE_REGNO (val) = -1; VALUE_LAZY (val) = 0; VALUE_OPTIMIZED_OUT (val) = 0; return val; } /* Allocate a value that has the correct length for COUNT repetitions type TYPE. */ value allocate_repeat_value (type, count) struct type *type; int count; { register value val; val = (value) xmalloc (sizeof (struct value) + TYPE_LENGTH (type) * count); VALUE_NEXT (val) = all_values; all_values = val; VALUE_TYPE (val) = type; VALUE_LVAL (val) = not_lval; VALUE_ADDRESS (val) = 0; VALUE_FRAME (val) = 0; VALUE_OFFSET (val) = 0; VALUE_BITPOS (val) = 0; VALUE_BITSIZE (val) = 0; VALUE_REPEATED (val) = 1; VALUE_REPETITIONS (val) = count; VALUE_REGNO (val) = -1; VALUE_LAZY (val) = 0; VALUE_OPTIMIZED_OUT (val) = 0; return val; } /* 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. */ value value_mark () { return all_values; } /* Free all values allocated since MARK was obtained by value_mark (except for those released). */ void value_free_to_mark (mark) value mark; { value val, 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 () { register value val, 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 (val) register value val; { register 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; } } } /* Return a copy of the value ARG. It contains the same contents, for same memory address, but it's a different block of storage. */ value value_copy (arg) value arg; { register value val; register struct type *type = VALUE_TYPE (arg); if (VALUE_REPEATED (arg)) val = allocate_repeat_value (type, VALUE_REPETITIONS (arg)); else val = allocate_value (type); 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_REGNO (val) = VALUE_REGNO (arg); VALUE_LAZY (val) = VALUE_LAZY (arg); if (!VALUE_LAZY (val)) { memcpy (VALUE_CONTENTS_RAW (val), VALUE_CONTENTS_RAW (arg), TYPE_LENGTH (VALUE_TYPE (arg)) * (VALUE_REPEATED (arg) ? VALUE_REPETITIONS (arg) : 1)); } 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 (val) value val; { int i; /* Check error now if about to store an invalid float. We return -1 to the caller, but allow them to continue, e.g. to print it as "Nan". */ if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FLT) { unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &i); if (i) return -1; /* Indicate value not saved in history */ } /* 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) { register 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; /* 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); VALUE_LVAL (val) = not_lval; release_value (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. */ value access_value_history (num) int num; { register 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 $%d.", absnum); absnum--; /* Now absnum is always absolute and origin zero. */ chunk = value_history_chain; for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; i > 0; i--) chunk = chunk->next; return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); } /* Clear the value history entirely. Must be done when new symbol tables are loaded, because the type pointers become invalid. */ void clear_value_history () { register struct value_history_chunk *next; register int i; register value val; while (value_history_chain) { for (i = 0; i < VALUE_HISTORY_CHUNK; i++) if ((val = value_history_chain->values[i]) != NULL) free ((PTR)val); next = value_history_chain->next; free ((PTR)value_history_chain); value_history_chain = next; } value_history_count = 0; } static void show_values (num_exp, from_tty) char *num_exp; int from_tty; { register int i; register value val; static int num = 1; if (num_exp) { /* "info history +" should print from the stored position. "info history " should print around value number . */ if (num_exp[0] != '+' || num_exp[1] != '\0') num = parse_and_eval_address (num_exp) - 5; } else { /* "info history" means print the last 10 values. */ num = value_history_count - 9; } if (num <= 0) num = 1; for (i = num; i < num + 10 && i <= value_history_count; i++) { val = access_value_history (i); printf_filtered ("$%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 (name) char *name; { register struct internalvar *var; for (var = internalvars; var; var = var->next) if (STREQ (var->name, name)) 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; } value value_of_internalvar (var) struct internalvar *var; { register value val; #ifdef IS_TRAPPED_INTERNALVAR if (IS_TRAPPED_INTERNALVAR (var->name)) return VALUE_OF_TRAPPED_INTERNALVAR (var); #endif 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 (var, offset, bitpos, bitsize, newval) struct internalvar *var; int offset, bitpos, bitsize; value newval; { register char *addr = VALUE_CONTENTS (var->value) + offset; #ifdef IS_TRAPPED_INTERNALVAR if (IS_TRAPPED_INTERNALVAR (var->name)) SET_TRAPPED_INTERNALVAR (var, newval, bitpos, bitsize, offset); #endif 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 (var, val) struct internalvar *var; value val; { #ifdef IS_TRAPPED_INTERNALVAR if (IS_TRAPPED_INTERNALVAR (var->name)) SET_TRAPPED_INTERNALVAR (var, val, 0, 0, 0); #endif free ((PTR)var->value); var->value = value_copy (val); /* 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 (var->value)) value_fetch_lazy (var->value); release_value (var->value); } char * internalvar_name (var) struct internalvar *var; { return var->name; } /* Free all internalvars. Done when new symtabs are loaded, because that makes the values invalid. */ void clear_internalvars () { register struct internalvar *var; while (internalvars) { var = internalvars; internalvars = var->next; free ((PTR)var->name); free ((PTR)var->value); free ((PTR)var); } } static void show_convenience (ignore, from_tty) char *ignore; int from_tty; { register struct internalvar *var; int varseen = 0; for (var = internalvars; var; var = var->next) { #ifdef IS_TRAPPED_INTERNALVAR if (IS_TRAPPED_INTERNALVAR (var->name)) continue; #endif 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 (val) register 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. */ if (TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_ENUM) COERCE_ARRAY (val); return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); } double value_as_double (val) register value val; { double 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. */ CORE_ADDR value_as_pointer (val) 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 return value_as_long (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. */ /* FIXME: This should be rewritten as a switch statement for speed and ease of comprehension. */ LONGEST unpack_long (type, valaddr) struct type *type; char *valaddr; { register enum type_code code = TYPE_CODE (type); register int len = TYPE_LENGTH (type); register int nosign = TYPE_UNSIGNED (type); switch (code) { case TYPE_CODE_ENUM: case TYPE_CODE_BOOL: case TYPE_CODE_INT: case TYPE_CODE_CHAR: if (nosign) return extract_unsigned_integer (valaddr, len); else return extract_signed_integer (valaddr, len); case TYPE_CODE_FLT: return extract_floating (valaddr, len); 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_address (valaddr, len); case TYPE_CODE_MEMBER: error ("not implemented: member types in unpack_long"); default: error ("Value can't be converted to intenot integer or pointer."); } 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. */ double unpack_double (type, valaddr, invp) struct type *type; char *valaddr; int *invp; { register enum type_code code = TYPE_CODE (type); register int len = TYPE_LENGTH (type); register int nosign = TYPE_UNSIGNED (type); *invp = 0; /* Assume valid. */ if (code == TYPE_CODE_FLT) { if (INVALID_FLOAT (valaddr, len)) { *invp = 1; return 1.234567891011121314; } return extract_floating (valaddr, TYPE_LENGTH (type)); } else if (nosign) { /* Unsigned -- be sure we compensate for signed LONGEST. */ return (unsigned LONGEST) 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_pointer() 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 (type, valaddr) struct type *type; 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); } /* 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 fields. FIELDNO says which field. For C++, must also be able to return values from static fields */ value value_primitive_field (arg1, offset, fieldno, arg_type) register value arg1; int offset; register int fieldno; register struct type *arg_type; { register value v; register struct type *type; check_stub_type (arg_type); type = TYPE_FIELD_TYPE (arg_type, fieldno); /* Handle packed fields */ offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; if (TYPE_FIELD_BITSIZE (arg_type, fieldno)) { v = value_from_longest (type, unpack_field_as_long (arg_type, VALUE_CONTENTS (arg1), fieldno)); VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8; VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno); } else { 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_LVAL (v) = VALUE_LVAL (arg1); if (VALUE_LVAL (arg1) == lval_internalvar) VALUE_LVAL (v) = lval_internalvar_component; VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1); VALUE_OFFSET (v) = offset + VALUE_OFFSET (arg1); return v; } /* Given a value ARG1 of a struct or union type, extract and return the value of one of its fields. FIELDNO says which field. For C++, must also be able to return values from static fields */ value value_field (arg1, fieldno) register 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. */ value value_fn_field (arg1p, f, j, type, offset) value *arg1p; struct fn_field *f; int j; struct type *type; int offset; { register value v; register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); struct symbol *sym; sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j), 0, VAR_NAMESPACE, 0, NULL); if (! sym) return (value)NULL; /* error ("Internal error: could not find physical method named %s", TYPE_FN_FIELD_PHYSNAME (f, j)); */ v = allocate_value (ftype); VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); VALUE_TYPE (v) = ftype; 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; } /* Return a virtual function as a value. ARG1 is the object which provides the virtual function table pointer. *ARG1P is side-effected in calling this function. F is the list of member functions which contains the desired virtual function. J is an index into F which provides the desired virtual function. TYPE is the type in which F is located. */ value value_virtual_fn_field (arg1p, f, j, type, offset) value *arg1p; struct fn_field *f; int j; struct type *type; int offset; { value arg1 = *arg1p; /* First, get the virtual function table pointer. That comes with a strange type, so cast it to type `pointer to long' (which should serve just fine as a function type). Then, index into the table, and convert final value to appropriate function type. */ value entry, vfn, vtbl; value vi = value_from_longest (builtin_type_int, (LONGEST) TYPE_FN_FIELD_VOFFSET (f, j)); struct type *fcontext = TYPE_FN_FIELD_FCONTEXT (f, j); struct type *context; if (fcontext == NULL) /* We don't have an fcontext (e.g. the program was compiled with g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE. This won't work right for multiple inheritance, but at least we should do as well as GDB 3.x did. */ fcontext = TYPE_VPTR_BASETYPE (type); context = lookup_pointer_type (fcontext); /* Now context is a pointer to the basetype containing the vtbl. */ if (TYPE_TARGET_TYPE (context) != VALUE_TYPE (arg1)) arg1 = value_ind (value_cast (context, value_addr (arg1))); context = VALUE_TYPE (arg1); /* Now context is the basetype containing the vtbl. */ /* This type may have been defined before its virtual function table was. If so, fill in the virtual function table entry for the type now. */ if (TYPE_VPTR_FIELDNO (context) < 0) fill_in_vptr_fieldno (context); /* The virtual function table is now an array of structures which have the form { int16 offset, delta; void *pfn; }. */ vtbl = value_ind (value_primitive_field (arg1, 0, TYPE_VPTR_FIELDNO (context), TYPE_VPTR_BASETYPE (context))); /* Index into the virtual function table. This is hard-coded because looking up a field is not cheap, and it may be important to save time, e.g. if the user has set a conditional breakpoint calling a virtual function. */ entry = value_subscript (vtbl, vi); /* Move the `this' pointer according to the virtual function table. */ VALUE_OFFSET (arg1) += value_as_long (value_field (entry, 0))/* + offset*/; if (! VALUE_LAZY (arg1)) { VALUE_LAZY (arg1) = 1; value_fetch_lazy (arg1); } vfn = value_field (entry, 2); /* Reinstantiate the function pointer with the correct type. */ VALUE_TYPE (vfn) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)); *arg1p = arg1; return vfn; } /* ARG is a pointer to an object we know to be at least a DTYPE. BTYPE is the most derived basetype that has already been searched (and need not be searched again). After looking at the vtables between BTYPE and DTYPE, return the most derived type we find. The caller must be satisfied when the return value == DTYPE. FIXME-tiemann: should work with dossier entries as well. */ static value value_headof (in_arg, btype, dtype) value in_arg; struct type *btype, *dtype; { /* First collect the vtables we must look at for this object. */ /* FIXME-tiemann: right now, just look at top-most vtable. */ value arg, vtbl, entry, best_entry = 0; int i, nelems; int offset, best_offset = 0; struct symbol *sym; CORE_ADDR pc_for_sym; char *demangled_name; struct minimal_symbol *msymbol; btype = TYPE_VPTR_BASETYPE (dtype); check_stub_type (btype); arg = in_arg; if (btype != dtype) arg = value_cast (lookup_pointer_type (btype), arg); vtbl = value_ind (value_field (value_ind (arg), TYPE_VPTR_FIELDNO (btype))); /* Check that VTBL looks like it points to a virtual function table. */ msymbol = lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl)); if (msymbol == NULL || !VTBL_PREFIX_P (demangled_name = SYMBOL_NAME (msymbol))) { /* If we expected to find a vtable, but did not, let the user know that we aren't happy, but don't throw an error. FIXME: there has to be a better way to do this. */ struct type *error_type = (struct type *)xmalloc (sizeof (struct type)); memcpy (error_type, VALUE_TYPE (in_arg), sizeof (struct type)); TYPE_NAME (error_type) = savestring ("suspicious *", sizeof ("suspicious *")); VALUE_TYPE (in_arg) = error_type; return in_arg; } /* Now search through the virtual function table. */ entry = value_ind (vtbl); nelems = longest_to_int (value_as_long (value_field (entry, 2))); for (i = 1; i <= nelems; i++) { entry = value_subscript (vtbl, value_from_longest (builtin_type_int, (LONGEST) i)); offset = longest_to_int (value_as_long (value_field (entry, 0))); /* If we use '<=' we can handle single inheritance * where all offsets are zero - just use the first entry found. */ if (offset <= best_offset) { best_offset = offset; best_entry = entry; } } /* Move the pointer according to BEST_ENTRY's offset, and figure out what type we should return as the new pointer. */ if (best_entry == 0) { /* An alternative method (which should no longer be necessary). * But we leave it in for future use, when we will hopefully * have optimizes the vtable to use thunks instead of offsets. */ /* Use the name of vtable itself to extract a base type. */ demangled_name += 4; /* Skip _vt$ prefix. */ } else { pc_for_sym = value_as_pointer (value_field (best_entry, 2)); sym = find_pc_function (pc_for_sym); demangled_name = cplus_demangle (SYMBOL_NAME (sym), DMGL_ANSI); *(strchr (demangled_name, ':')) = '\0'; } sym = lookup_symbol (demangled_name, 0, VAR_NAMESPACE, 0, 0); if (sym == NULL) error ("could not find type declaration for `%s'", demangled_name); if (best_entry) { free (demangled_name); arg = value_add (value_cast (builtin_type_int, arg), value_field (best_entry, 0)); } else arg = in_arg; VALUE_TYPE (arg) = lookup_pointer_type (SYMBOL_TYPE (sym)); return arg; } /* ARG is a pointer object of type TYPE. If TYPE has virtual function tables, probe ARG's tables (including the vtables of its baseclasses) to figure out the most derived type that ARG could actually be a pointer to. */ value value_from_vtable_info (arg, type) value arg; struct type *type; { /* Take care of preliminaries. */ if (TYPE_VPTR_FIELDNO (type) < 0) fill_in_vptr_fieldno (type); if (TYPE_VPTR_FIELDNO (type) < 0 || VALUE_REPEATED (arg)) return 0; return value_headof (arg, 0, type); } /* Return true if the INDEXth field of TYPE is a virtual baseclass pointer which is for the base class whose type is BASECLASS. */ static int vb_match (type, index, basetype) struct type *type; int index; struct type *basetype; { struct type *fieldtype; char *name = TYPE_FIELD_NAME (type, index); char *field_class_name = NULL; if (*name != '_') return 0; /* gcc 2.4 uses _vb$. */ if (name[1] == 'v' && name[2] == 'b' && name[3] == CPLUS_MARKER) field_class_name = name + 4; /* gcc 2.5 will use __vb_. */ if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_') field_class_name = name + 5; if (field_class_name == NULL) /* This field is not a virtual base class pointer. */ return 0; /* It's a virtual baseclass pointer, now we just need to find out whether it is for this baseclass. */ fieldtype = TYPE_FIELD_TYPE (type, index); if (fieldtype == NULL || TYPE_CODE (fieldtype) != TYPE_CODE_PTR) /* "Can't happen". */ return 0; /* What we check for is that either the types are equal (needed for nameless types) or have the same name. This is ugly, and a more elegant solution should be devised (which would probably just push the ugliness into symbol reading unless we change the stabs format). */ if (TYPE_TARGET_TYPE (fieldtype) == basetype) return 1; if (TYPE_NAME (basetype) != NULL && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL && STREQ (TYPE_NAME (basetype), TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)))) return 1; return 0; } /* Compute the offset of the baseclass which is the INDEXth baseclass of class TYPE, for a value ARG, wih extra offset of OFFSET. The result is the offste of the baseclass value relative to (the address of)(ARG) + OFFSET. -1 is returned on error. */ int baseclass_offset (type, index, arg, offset) struct type *type; int index; value arg; int offset; { struct type *basetype = TYPE_BASECLASS (type, index); if (BASETYPE_VIA_VIRTUAL (type, index)) { /* Must hunt for the pointer to this virtual baseclass. */ register int i, len = TYPE_NFIELDS (type); register int n_baseclasses = TYPE_N_BASECLASSES (type); /* First look for the virtual baseclass pointer in the fields. */ for (i = n_baseclasses; i < len; i++) { if (vb_match (type, i, basetype)) { CORE_ADDR addr = unpack_pointer (TYPE_FIELD_TYPE (type, i), VALUE_CONTENTS (arg) + VALUE_OFFSET (arg) + offset + (TYPE_FIELD_BITPOS (type, i) / 8)); if (VALUE_LVAL (arg) != lval_memory) return -1; return addr - (LONGEST) (VALUE_ADDRESS (arg) + VALUE_OFFSET (arg) + offset); } } /* Not in the fields, so try looking through the baseclasses. */ for (i = index+1; i < n_baseclasses; i++) { int boffset = baseclass_offset (type, i, arg, offset); if (boffset) return boffset; } /* Not found. */ return -1; } /* Baseclass is easily computed. */ return TYPE_BASECLASS_BITPOS (type, index) / 8; } /* Compute the address of the baseclass which is the INDEXth baseclass of class TYPE. The TYPE base of the object is at VALADDR. If ERRP is non-NULL, set *ERRP to be the errno code of any error, or 0 if no error. In that case the return value is not the address of the baseclasss, but the address which could not be read successfully. */ /* FIXME Fix remaining uses of baseclass_addr to use baseclass_offset */ char * baseclass_addr (type, index, valaddr, valuep, errp) struct type *type; int index; char *valaddr; value *valuep; int *errp; { struct type *basetype = TYPE_BASECLASS (type, index); if (errp) *errp = 0; if (BASETYPE_VIA_VIRTUAL (type, index)) { /* Must hunt for the pointer to this virtual baseclass. */ register int i, len = TYPE_NFIELDS (type); register int n_baseclasses = TYPE_N_BASECLASSES (type); /* First look for the virtual baseclass pointer in the fields. */ for (i = n_baseclasses; i < len; i++) { if (vb_match (type, i, basetype)) { value val = allocate_value (basetype); CORE_ADDR addr; int status; addr = unpack_pointer (TYPE_FIELD_TYPE (type, i), valaddr + (TYPE_FIELD_BITPOS (type, i) / 8)); status = target_read_memory (addr, VALUE_CONTENTS_RAW (val), TYPE_LENGTH (basetype)); VALUE_LVAL (val) = lval_memory; VALUE_ADDRESS (val) = addr; if (status != 0) { if (valuep) *valuep = NULL; release_value (val); value_free (val); if (errp) *errp = status; return (char *)addr; } else { if (valuep) *valuep = val; return (char *) VALUE_CONTENTS (val); } } } /* Not in the fields, so try looking through the baseclasses. */ for (i = index+1; i < n_baseclasses; i++) { char *baddr; baddr = baseclass_addr (type, i, valaddr, valuep, errp); if (baddr) return baddr; } /* Not found. */ if (valuep) *valuep = 0; return 0; } /* Baseclass is easily computed. */ if (valuep) *valuep = 0; return valaddr + TYPE_BASECLASS_BITPOS (type, index) / 8; } /* 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 (type, valaddr, fieldno) struct type *type; char *valaddr; int fieldno; { unsigned LONGEST val; unsigned LONGEST valmask; int bitpos = TYPE_FIELD_BITPOS (type, fieldno); int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); int lsbcount; val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val)); /* Extract bits. See comment above. */ #if BITS_BIG_ENDIAN lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize); #else lsbcount = (bitpos % 8); #endif 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 * sizeof (val))) { valmask = (((unsigned LONGEST) 1) << bitsize) - 1; val &= valmask; if (!TYPE_UNSIGNED (TYPE_FIELD_TYPE (type, fieldno))) { 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 (addr, fieldval, bitpos, bitsize) char *addr; LONGEST fieldval; int bitpos, bitsize; { LONGEST oword; /* Reject values too big to fit in the field in question, otherwise adjoining fields may be corrupted. */ if (bitsize < (8 * sizeof (fieldval)) && 0 != (fieldval & ~((1<= size of oword */ if (bitsize < 8 * sizeof (oword)) oword &= ~(((((unsigned LONGEST)1) << bitsize) - 1) << bitpos); else oword &= ~((~(unsigned LONGEST)0) << bitpos); oword |= fieldval << bitpos; store_signed_integer (addr, sizeof oword, oword); } /* Convert C numbers into newly allocated values */ value value_from_longest (type, num) struct type *type; register LONGEST num; { register value val = allocate_value (type); register enum type_code code = TYPE_CODE (type); register int len = TYPE_LENGTH (type); switch (code) { case TYPE_CODE_INT: case TYPE_CODE_CHAR: case TYPE_CODE_ENUM: case TYPE_CODE_BOOL: store_signed_integer (VALUE_CONTENTS_RAW (val), len, num); break; case TYPE_CODE_REF: case TYPE_CODE_PTR: /* This assumes that all pointers of a given length have the same form. */ store_address (VALUE_CONTENTS_RAW (val), len, (CORE_ADDR) num); break; default: error ("Unexpected type encountered for integer constant."); } return val; } value value_from_double (type, num) struct type *type; double num; { register value val = allocate_value (type); register enum type_code code = TYPE_CODE (type); register int len = TYPE_LENGTH (type); if (code == TYPE_CODE_FLT) { store_floating (VALUE_CONTENTS_RAW (val), len, 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). */ value value_being_returned (valtype, retbuf, struct_return) register struct type *valtype; char retbuf[REGISTER_BYTES]; int struct_return; /*ARGSUSED*/ { register value val; CORE_ADDR addr; #if defined (EXTRACT_STRUCT_VALUE_ADDRESS) /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */ if (struct_return) { addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf); if (!addr) error ("Function return value unknown"); return value_at (valtype, addr); } #endif val = allocate_value (valtype); 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. */ #if !defined (USE_STRUCT_CONVENTION) #define USE_STRUCT_CONVENTION(gcc_p, type)\ (!((gcc_p == 1) && (TYPE_LENGTH (value_type) == 1 \ || TYPE_LENGTH (value_type) == 2 \ || TYPE_LENGTH (value_type) == 4 \ || TYPE_LENGTH (value_type) == 8 \ ) \ )) #endif /* 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. */ int using_struct_return (function, funcaddr, value_type, gcc_p) value function; CORE_ADDR funcaddr; struct type *value_type; int gcc_p; /*ARGSUSED*/ { 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 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 (val) value val; { register enum type_code code = TYPE_CODE (VALUE_TYPE (val)); double dbuf; LONGEST lbuf; 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."); /* FIXME, this is bogus. We don't know what the return conventions are, or how values should be promoted.... */ if (code == TYPE_CODE_FLT) { dbuf = value_as_double (val); STORE_RETURN_VALUE (VALUE_TYPE (val), (char *)&dbuf); } else { lbuf = value_as_long (val); STORE_RETURN_VALUE (VALUE_TYPE (val), (char *)&lbuf); } } void _initialize_values () { 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); }