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authorgdb-2.4+.aux.coff <gdb@fsf.org>1988-01-16 04:39:57 +0000
committerPedro Alves <palves@redhat.com>2012-06-03 15:36:30 +0100
commit7b4ac7e1ed2c4616bce56d1760807798be87ac9e (patch)
tree777c9f6aba126e91e4a25d7b1fa34c2213d038da /gdb/values.c
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Diffstat (limited to 'gdb/values.c')
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diff --git a/gdb/values.c b/gdb/values.c
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+++ b/gdb/values.c
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+/* 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