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Diffstat (limited to 'gdb/values.c')
| -rw-r--r-- | gdb/values.c | 749 |
1 files changed, 749 insertions, 0 deletions
diff --git a/gdb/values.c b/gdb/values.c new file mode 100644 index 0000000..9af5d96 --- /dev/null +++ b/gdb/values.c @@ -0,0 +1,749 @@ +/* Low level packing and unpacking of values for GDB. + Copyright (C) 1986, 1987 Free Software Foundation, Inc. + +GDB is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY. No author or distributor accepts responsibility to anyone +for the consequences of using it or for whether it serves any +particular purpose or works at all, unless he says so in writing. +Refer to the GDB General Public License for full details. + +Everyone is granted permission to copy, modify and redistribute GDB, +but only under the conditions described in the GDB General Public +License. A copy of this license is supposed to have been given to you +along with GDB so you can know your rights and responsibilities. It +should be in a file named COPYING. Among other things, the copyright +notice and this notice must be preserved on all copies. + +In other words, go ahead and share GDB, but don't try to stop +anyone else from sharing it farther. Help stamp out software hoarding! +*/ + +#include <stdio.h> +#include "defs.h" +#include "initialize.h" +#include "param.h" +#include "symtab.h" +#include "value.h" + +/* 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 */ + +START_FILE + +/* 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; + + 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_OFFSET (val) = 0; + VALUE_BITPOS (val) = 0; + VALUE_BITSIZE (val) = 0; + VALUE_REPEATED (val) = 0; + VALUE_REPETITIONS (val) = 0; + VALUE_REGNO (val) = -1; + 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_OFFSET (val) = 0; + VALUE_BITPOS (val) = 0; + VALUE_BITSIZE (val) = 0; + VALUE_REPEATED (val) = 1; + VALUE_REPETITIONS (val) = count; + VALUE_REGNO (val) = -1; + return 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); + 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. */ + +static 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); + bcopy (VALUE_CONTENTS (arg), VALUE_CONTENTS (val), + 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. */ + +int +record_latest_value (val) + value val; +{ + register int i; + + /* Get error now if about to store an invalid float. */ + if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FLT) + value_as_double (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) + { + register struct value_history_chunk *new + = (struct value_history_chunk *) xmalloc (sizeof (struct value_history_chunk)); + bzero (new->values, sizeof new->values); + new->next = value_history_chain; + value_history_chain = new; + } + + value_history_chain->values[i] = val; + 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 $%d.", absnum); + + absnum--; + + /* Now absnum is always absolute and origin zero. */ + + chunk = value_history_chain; + for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; + i > 0; i--) + chunk = chunk->next; + + return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); +} + +/* Clear the value history entirely. + Must be done when new symbol tables are loaded, + because the type pointers become invalid. */ + +void +clear_value_history () +{ + register struct value_history_chunk *next; + register int i; + register value val; + + while (value_history_chain) + { + for (i = 0; i < VALUE_HISTORY_CHUNK; i++) + if (val = value_history_chain->values[i]) + free (val); + next = value_history_chain->next; + free (value_history_chain); + value_history_chain = next; + } + value_history_count = 0; +} + +static void +history_info (num_exp) + char *num_exp; +{ + register int i; + register value val; + register int num; + + if (num_exp) + num = parse_and_eval_address (num_exp) - 5; + else + num = value_history_count - 9; + + if (num <= 0) + num = 1; + + for (i = num; i < num + 10 && i <= value_history_count; i++) + { + val = access_value_history (i); + printf ("$%d = ", i); + value_print (val, stdout); + printf ("\n"); + } +} + +/* 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 (!strcmp (var->name, name)) + return var; + + var = (struct internalvar *) xmalloc (sizeof (struct internalvar)); + var->name = concat (name, "", ""); + 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 = value_copy (var->value); + VALUE_LVAL (val) = lval_internalvar; + VALUE_INTERNALVAR (val) = var; +} + +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; + if (bitsize) + modify_field (addr, value_as_long (newval), + bitpos, bitsize); + else + bcopy (VALUE_CONTENTS (newval), addr, + TYPE_LENGTH (VALUE_TYPE (newval))); +} + +void +set_internalvar (var, val) + struct internalvar *var; + value val; +{ + free (var->value); + var->value = value_copy (val); + 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 (var->name); + free (var->value); + free (var); + } +} + +static void +convenience_info () +{ + register struct internalvar *var; + + if (internalvars) + printf ("Debugger convenience variables:\n\n"); + else + printf ("No debugger convenience variables now defined.\n\ +Convenience variables have names starting with \"$\";\n\ +use \"set\" as in \"set $foo = 5\" to define them.\n"); + + for (var = internalvars; var; var = var->next) + { + printf ("$%s: ", var->name); + value_print (var->value, stdout); + printf ("\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. */ + +long +value_as_long (val) + register value val; +{ + return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); +} + +double +value_as_double (val) + register value val; +{ + return unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val)); +} + +/* Unpack raw data (copied from debugee) 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. */ + +long +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); + + if (code == TYPE_CODE_ENUM) + code = TYPE_CODE_INT; + if (code == TYPE_CODE_FLT) + { + if (len == sizeof (float)) + return * (float *) valaddr; + + if (len == sizeof (double)) + return * (double *) valaddr; + } + else if (code == TYPE_CODE_INT && nosign) + { + if (len == sizeof (char)) + return * (unsigned char *) valaddr; + + if (len == sizeof (short)) + return * (unsigned short *) valaddr; + + if (len == sizeof (int)) + return * (unsigned int *) valaddr; + + if (len == sizeof (long)) + return * (unsigned long *) valaddr; + } + else if (code == TYPE_CODE_INT) + { + if (len == sizeof (char)) + return * (char *) valaddr; + + if (len == sizeof (short)) + return * (short *) valaddr; + + if (len == sizeof (int)) + return * (int *) valaddr; + + if (len == sizeof (long)) + return * (long *) valaddr; + } + else if (code == TYPE_CODE_PTR) + { + if (len == sizeof (char *)) + return (CORE_ADDR) * (char **) valaddr; + } + + error ("Value not integer or pointer."); +} + +double +unpack_double (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); + + if (code == TYPE_CODE_FLT) + { + if (INVALID_FLOAT (valaddr, len)) + error ("Invalid floating value found in program."); + + if (len == sizeof (float)) + return * (float *) valaddr; + + if (len == sizeof (double)) + return * (double *) valaddr; + } + else if (code == TYPE_CODE_INT && nosign) + { + if (len == sizeof (char)) + return * (unsigned char *) valaddr; + + if (len == sizeof (short)) + return * (unsigned short *) valaddr; + + if (len == sizeof (int)) + return * (unsigned int *) valaddr; + + if (len == sizeof (long)) + return * (unsigned long *) valaddr; + } + else if (code == TYPE_CODE_INT) + { + if (len == sizeof (char)) + return * (char *) valaddr; + + if (len == sizeof (short)) + return * (short *) valaddr; + + if (len == sizeof (int)) + return * (int *) valaddr; + + if (len == sizeof (long)) + return * (long *) valaddr; + } + + error ("Value not floating number."); +} + +/* Given a value ARG1 of a struct or union type, + extract and return the value of one of its fields. + FIELDNO says which field. */ + +value +value_field (arg1, fieldno) + register value arg1; + register int fieldno; +{ + register value v; + register struct type *type = TYPE_FIELD_TYPE (VALUE_TYPE (arg1), fieldno); + register int offset; + + /* Handle packed fields */ + + offset = TYPE_FIELD_BITPOS (VALUE_TYPE (arg1), fieldno) / 8; + if (TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1), fieldno)) + { + v = value_from_long (type, + unpack_field_as_long (VALUE_TYPE (arg1), + VALUE_CONTENTS (arg1), + fieldno)); + VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (VALUE_TYPE (arg1), fieldno) % 8; + VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (VALUE_TYPE (arg1), fieldno); + } + else + { + v = allocate_value (type); + bcopy (VALUE_CONTENTS (arg1) + offset, + VALUE_CONTENTS (v), + 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; +} + +long +unpack_field_as_long (type, valaddr, fieldno) + struct type *type; + char *valaddr; + int fieldno; +{ + long val; + int bitpos = TYPE_FIELD_BITPOS (type, fieldno); + int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); + union { int i; char c; } test; + + bcopy (valaddr + bitpos / 8, &val, sizeof val); + + /* Extracting bits depends on endianness of the machine. */ + test.i = 1; + if (test.c == 1) + /* Little-endian. */ + val = val >> (bitpos % 8); + else + val = val >> (sizeof val * 8 - bitpos % 8 - bitsize); + + val &= (1 << bitsize) - 1; + return val; +} + +modify_field (addr, fieldval, bitpos, bitsize) + char *addr; + int fieldval; + int bitpos, bitsize; +{ + long oword; + union { int i; char c; } test; + + bcopy (addr, &oword, sizeof oword); + + /* Shifting for bit field depends on endianness of the machine. */ + test.c = 1; + if (test.i != 1) + /* not little-endian: assume big-endian. */ + bitpos = sizeof oword * 8 - bitpos - bitsize; + + oword &= ~(((1 << bitsize) - 1) << bitpos); + oword |= fieldval << bitpos; + bcopy (&oword, addr, sizeof oword); +} + +/* Convert C numbers into newly allocated values */ + +value +value_from_long (type, num) + struct type *type; + register long 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_INT || code == TYPE_CODE_ENUM) + { + if (len == sizeof (char)) + * (char *) VALUE_CONTENTS (val) = num; + else if (len == sizeof (short)) + * (short *) VALUE_CONTENTS (val) = num; + else if (len == sizeof (int)) + * (int *) VALUE_CONTENTS (val) = num; + else if (len == sizeof (long)) + * (long *) VALUE_CONTENTS (val) = num; + else + error ("Integer type encountered with unexpected data length."); + } + else + 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) + { + if (len == sizeof (float)) + * (float *) VALUE_CONTENTS (val) = num; + else if (len == sizeof (double)) + * (double *) VALUE_CONTENTS (val) = num; + else + error ("Floating type encountered with unexpected data length."); + } + 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. */ + +value +value_being_returned (valtype, retbuf) + register struct type *valtype; + char retbuf[REGISTER_BYTES]; +{ + register value val; + + if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT + || TYPE_CODE (valtype) == TYPE_CODE_UNION) + return value_at (valtype, EXTRACT_STRUCT_VALUE_ADDRESS (retbuf)); + + val = allocate_value (valtype); + EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS (val)); + + return val; +} + +/* 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)); + char regbuf[REGISTER_BYTES]; + double dbuf; + long lbuf; + + if (code == TYPE_CODE_STRUCT + || code == TYPE_CODE_UNION) + error ("Specifying a struct or union return value is not supported."); + + if (code == TYPE_CODE_FLT) + { + dbuf = value_as_double (val); + + STORE_RETURN_VALUE (VALUE_TYPE (val), &dbuf); + } + else + { + lbuf = value_as_long (val); + STORE_RETURN_VALUE (VALUE_TYPE (val), &lbuf); + } +} + +static +initialize () +{ + add_info ("convenience", convenience_info, + "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 GDB:\n\ +\"$_\"holds the last address examined with \"x\" or \"info lines\",\n\ +\"$__\" holds the contents of the last address examined with \"x\"."); + + add_info ("history", history_info, + "Elements of value history (around item number IDX, or last ten)."); +} + +END_FILE |