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author | gdb-2.4+.aux.coff <gdb@fsf.org> | 1988-01-16 04:39:57 +0000 |
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committer | Pedro Alves <palves@redhat.com> | 2012-06-03 15:36:30 +0100 |
commit | 7b4ac7e1ed2c4616bce56d1760807798be87ac9e (patch) | |
tree | 777c9f6aba126e91e4a25d7b1fa34c2213d038da /gdb/findvar.c | |
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gdb-2.4+.aux.coff
Diffstat (limited to 'gdb/findvar.c')
-rw-r--r-- | gdb/findvar.c | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/gdb/findvar.c b/gdb/findvar.c new file mode 100644 index 0000000..1f92b16 --- /dev/null +++ b/gdb/findvar.c @@ -0,0 +1,409 @@ +/* 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 (®isters[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, ®isters[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 *) ®isters[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 *) ®isters[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, ®isters[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 |