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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/findvar.c
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Diffstat (limited to 'gdb/findvar.c')
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diff --git a/gdb/findvar.c b/gdb/findvar.c
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+/* Find a variable's value in memory, for GDB, the GNU debugger.
+ 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 "defs.h"
+#include "initialize.h"
+#include "param.h"
+#include "symtab.h"
+#include "frame.h"
+#include "value.h"
+
+CORE_ADDR read_register ();
+
+START_FILE
+
+/* Return the address in which frame FRAME's value of register REGNUM
+ has been saved in memory. Or return zero if it has not been saved.
+ If REGNUM specifies the SP, the value we return is actually
+ the SP value, not an address where it was saved. */
+
+static CORE_ADDR
+find_saved_register (frame, regnum)
+ FRAME frame;
+ int regnum;
+{
+ struct frame_info fi;
+ struct frame_saved_regs saved_regs;
+
+ register FRAME frame1 = 0;
+ register CORE_ADDR addr = 0;
+
+ while (1)
+ {
+ QUIT;
+ fi = get_prev_frame_info (frame1);
+ if (fi.frame == 0 || fi.frame == frame)
+ break;
+ get_frame_saved_regs (&fi, &saved_regs);
+ if (saved_regs.regs[regnum])
+ addr = saved_regs.regs[regnum];
+ frame1 = fi.frame;
+ }
+
+ return addr;
+}
+
+/* Copy the bytes of register REGNUM, relative to the current stack frame,
+ into our memory at MYADDR.
+ The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). */
+
+void
+read_relative_register_raw_bytes (regnum, myaddr)
+ int regnum;
+ char *myaddr;
+{
+ register CORE_ADDR addr;
+
+ if (regnum == FP_REGNUM)
+ {
+ bcopy (&selected_frame, myaddr, sizeof (CORE_ADDR));
+ return;
+ }
+
+ addr = find_saved_register (selected_frame, regnum);
+
+ if (addr)
+ {
+ if (regnum == SP_REGNUM)
+ {
+ CORE_ADDR buffer = addr;
+ bcopy (&buffer, myaddr, sizeof (CORE_ADDR));
+ }
+ else
+ read_memory (addr, myaddr, REGISTER_RAW_SIZE (regnum));
+ return;
+ }
+ read_register_bytes (REGISTER_BYTE (regnum),
+ myaddr, REGISTER_RAW_SIZE (regnum));
+}
+
+/* Return a `value' with the contents of register REGNUM
+ in its virtual format, with the type specified by
+ REGISTER_VIRTUAL_TYPE. */
+
+value
+value_of_register (regnum)
+ int regnum;
+{
+ register CORE_ADDR addr = find_saved_register (selected_frame, regnum);
+ register value val;
+ char raw_buffer[MAX_REGISTER_RAW_SIZE];
+ char virtual_buffer[MAX_REGISTER_VIRTUAL_SIZE];
+
+ if (addr)
+ {
+ if (regnum == SP_REGNUM)
+ return value_from_long (builtin_type_int, addr);
+ read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum));
+ }
+ else
+ read_register_bytes (REGISTER_BYTE (regnum), raw_buffer,
+ REGISTER_RAW_SIZE (regnum));
+
+ REGISTER_CONVERT_TO_VIRTUAL (regnum, raw_buffer, virtual_buffer);
+ val = allocate_value (REGISTER_VIRTUAL_TYPE (regnum));
+ bcopy (virtual_buffer, VALUE_CONTENTS (val), REGISTER_VIRTUAL_SIZE (regnum));
+ VALUE_LVAL (val) = addr ? lval_memory : lval_register;
+ VALUE_ADDRESS (val) = addr ? addr : REGISTER_BYTE (regnum);
+ VALUE_REGNO (val) = regnum;
+ return val;
+}
+
+/* Low level examining and depositing of registers.
+
+ Note that you must call `fetch_registers' once
+ before examining or depositing any registers. */
+
+char registers[REGISTER_BYTES];
+
+/* Copy LEN bytes of consecutive data from registers
+ starting with the REGBYTE'th byte of register data
+ into memory at MYADDR. */
+
+read_register_bytes (regbyte, myaddr, len)
+ int regbyte;
+ char *myaddr;
+ int len;
+{
+ bcopy (&registers[regbyte], myaddr, len);
+}
+
+/* Copy LEN bytes of consecutive data from memory at MYADDR
+ into registers starting with the REGBYTE'th byte of register data. */
+
+write_register_bytes (regbyte, myaddr, len)
+ int regbyte;
+ char *myaddr;
+ int len;
+{
+ bcopy (myaddr, &registers[regbyte], len);
+ if (have_inferior_p ())
+ store_inferior_registers (-1);
+}
+
+/* Return the contents of register REGNO,
+ regarding it as an integer. */
+
+CORE_ADDR
+read_register (regno)
+ int regno;
+{
+ /* This loses when REGISTER_RAW_SIZE (regno) != sizeof (int) */
+ return *(int *) &registers[REGISTER_BYTE (regno)];
+}
+
+/* Store VALUE in the register number REGNO, regarded as an integer. */
+
+void
+write_register (regno, val)
+ int regno, val;
+{
+ /* This loses when REGISTER_RAW_SIZE (regno) != sizeof (int) */
+ *(int *) &registers[REGISTER_BYTE (regno)] = val;
+
+ if (have_inferior_p ())
+ store_inferior_registers (regno);
+}
+
+/* Record that register REGNO contains VAL.
+ This is used when the value is obtained from the inferior or core dump,
+ so there is no need to store the value there. */
+
+void
+supply_register (regno, val)
+ int regno;
+ char *val;
+{
+ bcopy (val, &registers[REGISTER_BYTE (regno)], REGISTER_RAW_SIZE (regno));
+}
+
+/* Given a struct symbol for a variable,
+ and a stack frame address, read the value of the variable
+ and return a (pointer to a) struct value containing the value. */
+
+value
+read_var_value (var, frame)
+ register struct symbol *var;
+ FRAME frame;
+{
+ register value v;
+
+ struct frame_info fi;
+
+ struct type *type = SYMBOL_TYPE (var);
+ register CORE_ADDR addr = 0;
+ int val = SYMBOL_VALUE (var);
+ register int len;
+
+ if (SYMBOL_CLASS (var) == LOC_BLOCK)
+ type = lookup_function_type (type);
+
+ v = allocate_value (type);
+ VALUE_LVAL (v) = lval_memory; /* The most likely possibility. */
+ len = TYPE_LENGTH (type);
+
+ if (frame == 0) frame = selected_frame;
+
+ switch (SYMBOL_CLASS (var))
+ {
+ case LOC_CONST:
+ case LOC_LABEL:
+ bcopy (&val, VALUE_CONTENTS (v), len);
+ VALUE_LVAL (v) = not_lval;
+ return v;
+
+ case LOC_CONST_BYTES:
+ bcopy (val, VALUE_CONTENTS (v), len);
+ VALUE_LVAL (v) = not_lval;
+ return v;
+
+ case LOC_STATIC:
+ addr = val;
+ break;
+
+ case LOC_ARG:
+ fi = get_frame_info (frame);
+ addr = val + FRAME_ARGS_ADDRESS (fi);
+ break;
+
+ case LOC_LOCAL:
+ fi = get_frame_info (frame);
+ addr = val + FRAME_LOCALS_ADDRESS (fi);
+ break;
+
+ case LOC_TYPEDEF:
+ error ("Cannot look up value of a typedef");
+
+ case LOC_BLOCK:
+ VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (var));
+ return v;
+
+ case LOC_REGISTER:
+ {
+ char raw_buffer[MAX_REGISTER_RAW_SIZE];
+ char virtual_buffer[MAX_REGISTER_VIRTUAL_SIZE];
+
+ VALUE_REGNO (v) = val;
+
+ /* Locate the register's contents in a real register or in core;
+ read the data in raw format. */
+
+ addr = find_saved_register (frame, val);
+ if (addr == 0)
+ {
+ /* Value is really in a register. */
+
+ VALUE_LVAL (v) = lval_register;
+ VALUE_ADDRESS (v) = REGISTER_BYTE (val);
+
+ read_register_bytes (REGISTER_BYTE (val),
+ raw_buffer, REGISTER_RAW_SIZE (val));
+ }
+ else
+ {
+ /* Value was in a register that has been saved in memory. */
+
+ read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (val));
+ VALUE_ADDRESS (v) = addr;
+ }
+
+ /* Convert the raw contents to virtual contents.
+ (Just copy them if the formats are the same.) */
+
+ REGISTER_CONVERT_TO_VIRTUAL (val, raw_buffer, virtual_buffer);
+
+ if (REGISTER_CONVERTIBLE (val))
+ {
+ /* When the raw and virtual formats differ, the virtual format
+ corresponds to a specific data type. If we want that type,
+ copy the data into the value.
+ Otherwise, do a type-conversion. */
+
+ if (type != REGISTER_VIRTUAL_TYPE (val))
+ {
+ /* eg a variable of type `float' in a 68881 register
+ with raw type `extended' and virtual type `double'.
+ Fetch it as a `double' and then convert to `float'. */
+ v = allocate_value (REGISTER_VIRTUAL_TYPE (val));
+ bcopy (virtual_buffer, VALUE_CONTENTS (v), len);
+ v = value_cast (type, v);
+ }
+ else
+ bcopy (virtual_buffer, VALUE_CONTENTS (v), len);
+ }
+ else
+ {
+ /* Raw and virtual formats are the same for this register. */
+
+ union { int i; char c; } test;
+ /* If we want less than the full size, we need to
+ test for a big-endian or little-endian machine. */
+ test.i = 1;
+ if (test.c != 1 && len < REGISTER_RAW_SIZE (val))
+ {
+ /* Big-endian, and we want less than full size. */
+ VALUE_OFFSET (v) = REGISTER_RAW_SIZE (val) - len;
+ }
+
+ bcopy (virtual_buffer + VALUE_OFFSET (v),
+ VALUE_CONTENTS (v), len);
+ }
+
+ return v;
+ }
+ }
+
+ read_memory (addr, VALUE_CONTENTS (v), len);
+ VALUE_ADDRESS (v) = addr;
+ return v;
+}
+
+/* Given a struct symbol for a variable,
+ and a stack frame address,
+ return a (pointer to a) struct value containing the variable's address. */
+
+value
+locate_var_value (var, frame)
+ register struct symbol *var;
+ FRAME frame;
+{
+ register CORE_ADDR addr = 0;
+ int val = SYMBOL_VALUE (var);
+ struct frame_info fi;
+
+ if (frame == 0) frame = selected_frame;
+
+ switch (SYMBOL_CLASS (var))
+ {
+ case LOC_CONST:
+ case LOC_CONST_BYTES:
+ error ("Address requested for identifier \"%s\" which is a constant.",
+ SYMBOL_NAME (var));
+
+ case LOC_REGISTER:
+ addr = find_saved_register (frame, val);
+ if (addr != 0)
+ {
+ union { int i; char c; } test;
+ int len = TYPE_LENGTH (SYMBOL_TYPE (var));
+ /* If var is less than the full size of register, we need to
+ test for a big-endian or little-endian machine. */
+ test.i = 1;
+ if (test.c != 1 && len < REGISTER_RAW_SIZE (val))
+ /* Big-endian, and we want less than full size. */
+ addr+ = REGISTER_RAW_SIZE (val) - len;
+ break;
+ }
+ error ("Address requested for identifier \"%s\" which is in a register.",
+ SYMBOL_NAME (var));
+
+ case LOC_STATIC:
+ case LOC_LABEL:
+ addr = val;
+ break;
+
+ case LOC_ARG:
+ fi = get_frame_info (frame);
+ addr = val + FRAME_ARGS_ADDRESS (fi);
+ break;
+
+ case LOC_LOCAL:
+ fi = get_frame_info (frame);
+ addr = val + FRAME_LOCALS_ADDRESS (fi);
+ break;
+
+ case LOC_TYPEDEF:
+ error ("Address requested for identifier \"%s\" which is a typedef.",
+ SYMBOL_NAME (var));
+
+ case LOC_BLOCK:
+ addr = BLOCK_START (SYMBOL_BLOCK_VALUE (var));
+ break;
+ }
+
+ return value_cast (lookup_pointer_type (SYMBOL_TYPE (var)),
+ value_from_long (builtin_type_long, addr));
+}
+
+static
+initialize ()
+{}
+
+END_FILE