X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gdb%2Ffindvar.c;h=128bf5ea5d3adbe4ac647be0eacb2e12b1d620f7;hb=3b27ef472df3b4cdcdd54629281610d594c99c97;hp=e0ca12c81f958022a98f577248c201aba1a085c8;hpb=bb9bcb69cdddee8069bf24321f9a0e91ffd22f32;p=deliverable%2Fbinutils-gdb.git diff --git a/gdb/findvar.c b/gdb/findvar.c index e0ca12c81f..128bf5ea5d 100644 --- a/gdb/findvar.c +++ b/gdb/findvar.c @@ -1,8 +1,6 @@ /* Find a variable's value in memory, for GDB, the GNU debugger. - Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, - 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005, 2007, 2008, 2009, - 2010 Free Software Foundation, Inc. + Copyright (C) 1986-2015 Free Software Foundation, Inc. This file is part of GDB. @@ -27,14 +25,13 @@ #include "gdbcore.h" #include "inferior.h" #include "target.h" -#include "gdb_string.h" -#include "gdb_assert.h" #include "floatformat.h" #include "symfile.h" /* for overlay functions */ #include "regcache.h" #include "user-regs.h" #include "block.h" #include "objfiles.h" +#include "language.h" /* Basic byte-swapping routines. All 'extract' functions return a host-format integer from a target-format integer at ADDR which is @@ -263,12 +260,7 @@ struct value * value_of_register (int regnum, struct frame_info *frame) { struct gdbarch *gdbarch = get_frame_arch (frame); - CORE_ADDR addr; - int optim; struct value *reg_val; - int realnum; - gdb_byte raw_buffer[MAX_REGISTER_SIZE]; - enum lval_type lval; /* User registers lie completely outside of the range of normal registers. Catch them early so that the target never sees them. */ @@ -276,17 +268,8 @@ value_of_register (int regnum, struct frame_info *frame) + gdbarch_num_pseudo_regs (gdbarch)) return value_of_user_reg (regnum, frame); - frame_register (frame, regnum, &optim, &lval, &addr, &realnum, raw_buffer); - - reg_val = allocate_value (register_type (gdbarch, regnum)); - - memcpy (value_contents_raw (reg_val), raw_buffer, - register_size (gdbarch, regnum)); - VALUE_LVAL (reg_val) = lval; - set_value_address (reg_val, addr); - VALUE_REGNUM (reg_val) = regnum; - set_value_optimized_out (reg_val, optim); - VALUE_FRAME_ID (reg_val) = get_frame_id (frame); + reg_val = value_of_register_lazy (frame, regnum); + value_fetch_lazy (reg_val); return reg_val; } @@ -306,11 +289,10 @@ value_of_register_lazy (struct frame_info *frame, int regnum) /* We should have a valid (i.e. non-sentinel) frame. */ gdb_assert (frame_id_p (get_frame_id (frame))); - reg_val = allocate_value (register_type (gdbarch, regnum)); + reg_val = allocate_value_lazy (register_type (gdbarch, regnum)); VALUE_LVAL (reg_val) = lval_register; VALUE_REGNUM (reg_val) = regnum; VALUE_FRAME_ID (reg_val) = get_frame_id (frame); - set_value_lazy (reg_val, 1); return reg_val; } @@ -360,17 +342,15 @@ address_to_signed_pointer (struct gdbarch *gdbarch, struct type *type, int symbol_read_needs_frame (struct symbol *sym) { + if (SYMBOL_COMPUTED_OPS (sym) != NULL) + return SYMBOL_COMPUTED_OPS (sym)->read_needs_frame (sym); + switch (SYMBOL_CLASS (sym)) { /* All cases listed explicitly so that gcc -Wall will detect it if we failed to consider one. */ case LOC_COMPUTED: - /* FIXME: cagney/2004-01-26: It should be possible to - unconditionally call the SYMBOL_COMPUTED_OPS method when available. - Unfortunately DWARF 2 stores the frame-base (instead of the - function) location in a function's symbol. Oops! For the - moment enable this when/where applicable. */ - return SYMBOL_COMPUTED_OPS (sym)->read_needs_frame (sym); + gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); case LOC_REGISTER: case LOC_ARG: @@ -398,39 +378,71 @@ symbol_read_needs_frame (struct symbol *sym) return 1; } -/* Given a struct symbol for a variable, - and a stack frame id, read the value of the variable - and return a (pointer to a) struct value containing the value. - If the variable cannot be found, return a zero pointer. */ +/* Private data to be used with minsym_lookup_iterator_cb. */ + +struct minsym_lookup_data +{ + /* The name of the minimal symbol we are searching for. */ + const char *name; + + /* The field where the callback should store the minimal symbol + if found. It should be initialized to NULL before the search + is started. */ + struct bound_minimal_symbol result; +}; + +/* A callback function for gdbarch_iterate_over_objfiles_in_search_order. + It searches by name for a minimal symbol within the given OBJFILE. + The arguments are passed via CB_DATA, which in reality is a pointer + to struct minsym_lookup_data. */ + +static int +minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data) +{ + struct minsym_lookup_data *data = (struct minsym_lookup_data *) cb_data; + + gdb_assert (data->result.minsym == NULL); + + data->result = lookup_minimal_symbol (data->name, NULL, objfile); + + /* The iterator should stop iff a match was found. */ + return (data->result.minsym != NULL); +} + +/* A default implementation for the "la_read_var_value" hook in + the language vector which should work in most situations. */ struct value * -read_var_value (struct symbol *var, struct frame_info *frame) +default_read_var_value (struct symbol *var, struct frame_info *frame) { struct value *v; struct type *type = SYMBOL_TYPE (var); CORE_ADDR addr; - int len; - - if (SYMBOL_CLASS (var) == LOC_COMPUTED - || SYMBOL_CLASS (var) == LOC_REGISTER) - /* These cases do not use V. */ - v = NULL; - else - { - v = allocate_value (type); - VALUE_LVAL (v) = lval_memory; /* The most likely possibility. */ - } - len = TYPE_LENGTH (type); + /* Call check_typedef on our type to make sure that, if TYPE is + a TYPE_CODE_TYPEDEF, its length is set to the length of the target type + instead of zero. However, we do not replace the typedef type by the + target type, because we want to keep the typedef in order to be able to + set the returned value type description correctly. */ + check_typedef (type); if (symbol_read_needs_frame (var)) gdb_assert (frame); + if (SYMBOL_COMPUTED_OPS (var) != NULL) + return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame); + switch (SYMBOL_CLASS (var)) { case LOC_CONST: - /* Put the constant back in target format. */ - store_signed_integer (value_contents_raw (v), len, + if (is_dynamic_type (type)) + { + /* Value is a constant byte-sequence and needs no memory access. */ + type = resolve_dynamic_type (type, /* Unused address. */ 0); + } + /* Put the constant back in target format. */ + v = allocate_value (type); + store_signed_integer (value_contents_raw (v), TYPE_LENGTH (type), gdbarch_byte_order (get_type_arch (type)), (LONGEST) SYMBOL_VALUE (var)); VALUE_LVAL (v) = not_lval; @@ -438,11 +450,13 @@ read_var_value (struct symbol *var, struct frame_info *frame) case LOC_LABEL: /* Put the constant back in target format. */ + v = allocate_value (type); if (overlay_debugging) { CORE_ADDR addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), - SYMBOL_OBJ_SECTION (var)); + SYMBOL_OBJ_SECTION (symbol_objfile (var), + var)); store_typed_address (value_contents_raw (v), type, addr); } @@ -453,14 +467,22 @@ read_var_value (struct symbol *var, struct frame_info *frame) return v; case LOC_CONST_BYTES: - memcpy (value_contents_raw (v), SYMBOL_VALUE_BYTES (var), len); + if (is_dynamic_type (type)) + { + /* Value is a constant byte-sequence and needs no memory access. */ + type = resolve_dynamic_type (type, /* Unused address. */ 0); + } + v = allocate_value (type); + memcpy (value_contents_raw (v), SYMBOL_VALUE_BYTES (var), + TYPE_LENGTH (type)); VALUE_LVAL (v) = not_lval; return v; case LOC_STATIC: if (overlay_debugging) addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), - SYMBOL_OBJ_SECTION (var)); + SYMBOL_OBJ_SECTION (symbol_objfile (var), + var)); else addr = SYMBOL_VALUE_ADDRESS (var); break; @@ -468,7 +490,8 @@ read_var_value (struct symbol *var, struct frame_info *frame) case LOC_ARG: addr = get_frame_args_address (frame); if (!addr) - return 0; + error (_("Unknown argument list address for `%s'."), + SYMBOL_PRINT_NAME (var)); addr += SYMBOL_VALUE (var); break; @@ -479,7 +502,8 @@ read_var_value (struct symbol *var, struct frame_info *frame) argref = get_frame_args_address (frame); if (!argref) - return 0; + error (_("Unknown argument list address for `%s'."), + SYMBOL_PRINT_NAME (var)); argref += SYMBOL_VALUE (var); ref = value_at (lookup_pointer_type (type), argref); addr = value_as_address (ref); @@ -492,16 +516,18 @@ read_var_value (struct symbol *var, struct frame_info *frame) break; case LOC_TYPEDEF: - error (_("Cannot look up value of a typedef")); + error (_("Cannot look up value of a typedef `%s'."), + SYMBOL_PRINT_NAME (var)); break; case LOC_BLOCK: if (overlay_debugging) - set_value_address (v, symbol_overlayed_address - (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), SYMBOL_OBJ_SECTION (var))); + addr = symbol_overlayed_address + (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), + SYMBOL_OBJ_SECTION (symbol_objfile (var), var)); else - set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (var))); - return v; + addr = BLOCK_START (SYMBOL_BLOCK_VALUE (var)); + break; case LOC_REGISTER: case LOC_REGPARM_ADDR: @@ -517,45 +543,51 @@ read_var_value (struct symbol *var, struct frame_info *frame) frame); if (regval == NULL) - error (_("Value of register variable not available.")); + error (_("Value of register variable not available for `%s'."), + SYMBOL_PRINT_NAME (var)); addr = value_as_address (regval); - VALUE_LVAL (v) = lval_memory; } else { regval = value_from_register (type, regno, frame); if (regval == NULL) - error (_("Value of register variable not available.")); + error (_("Value of register variable not available for `%s'."), + SYMBOL_PRINT_NAME (var)); return regval; } } break; case LOC_COMPUTED: - /* FIXME: cagney/2004-01-26: It should be possible to - unconditionally call the SYMBOL_COMPUTED_OPS method when available. - Unfortunately DWARF 2 stores the frame-base (instead of the - function) location in a function's symbol. Oops! For the - moment enable this when/where applicable. */ - return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame); + gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); case LOC_UNRESOLVED: { + struct minsym_lookup_data lookup_data; struct minimal_symbol *msym; struct obj_section *obj_section; - msym = lookup_minimal_symbol (SYMBOL_LINKAGE_NAME (var), NULL, NULL); + memset (&lookup_data, 0, sizeof (lookup_data)); + lookup_data.name = SYMBOL_LINKAGE_NAME (var); + + gdbarch_iterate_over_objfiles_in_search_order + (symbol_arch (var), + minsym_lookup_iterator_cb, &lookup_data, + symbol_objfile (var)); + msym = lookup_data.result.minsym; + if (msym == NULL) - return 0; + error (_("No global symbol \"%s\"."), SYMBOL_LINKAGE_NAME (var)); if (overlay_debugging) - addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (msym), - SYMBOL_OBJ_SECTION (msym)); + addr = symbol_overlayed_address (BMSYMBOL_VALUE_ADDRESS (lookup_data.result), + MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, + msym)); else - addr = SYMBOL_VALUE_ADDRESS (msym); + addr = BMSYMBOL_VALUE_ADDRESS (lookup_data.result); - obj_section = SYMBOL_OBJ_SECTION (msym); + obj_section = MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, msym); if (obj_section && (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0) addr = target_translate_tls_address (obj_section->objfile, addr); @@ -563,32 +595,42 @@ read_var_value (struct symbol *var, struct frame_info *frame) break; case LOC_OPTIMIZED_OUT: - VALUE_LVAL (v) = not_lval; - set_value_optimized_out (v, 1); - return v; + return allocate_optimized_out_value (type); default: - error (_("Cannot look up value of a botched symbol.")); + error (_("Cannot look up value of a botched symbol `%s'."), + SYMBOL_PRINT_NAME (var)); break; } - set_value_address (v, addr); - set_value_lazy (v, 1); + v = value_at_lazy (type, addr); return v; } +/* Calls VAR's language la_read_var_value hook with the given arguments. */ + +struct value * +read_var_value (struct symbol *var, struct frame_info *frame) +{ + const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var)); + + gdb_assert (lang != NULL); + gdb_assert (lang->la_read_var_value != NULL); + + return lang->la_read_var_value (var, frame); +} + /* Install default attributes for register values. */ struct value * -default_value_from_register (struct type *type, int regnum, - struct frame_info *frame) +default_value_from_register (struct gdbarch *gdbarch, struct type *type, + int regnum, struct frame_id frame_id) { - struct gdbarch *gdbarch = get_frame_arch (frame); int len = TYPE_LENGTH (type); struct value *value = allocate_value (type); VALUE_LVAL (value) = lval_register; - VALUE_FRAME_ID (value) = get_frame_id (frame); + VALUE_FRAME_ID (value) = frame_id; VALUE_REGNUM (value) = regnum; /* Any structure stored in more than one register will always be @@ -605,6 +647,52 @@ default_value_from_register (struct type *type, int regnum, return value; } +/* VALUE must be an lval_register value. If regnum is the value's + associated register number, and len the length of the values type, + read one or more registers in FRAME, starting with register REGNUM, + until we've read LEN bytes. + + If any of the registers we try to read are optimized out, then mark the + complete resulting value as optimized out. */ + +void +read_frame_register_value (struct value *value, struct frame_info *frame) +{ + struct gdbarch *gdbarch = get_frame_arch (frame); + int offset = 0; + int reg_offset = value_offset (value); + int regnum = VALUE_REGNUM (value); + int len = TYPE_LENGTH (check_typedef (value_type (value))); + + gdb_assert (VALUE_LVAL (value) == lval_register); + + /* Skip registers wholly inside of REG_OFFSET. */ + while (reg_offset >= register_size (gdbarch, regnum)) + { + reg_offset -= register_size (gdbarch, regnum); + regnum++; + } + + /* Copy the data. */ + while (len > 0) + { + struct value *regval = get_frame_register_value (frame, regnum); + int reg_len = TYPE_LENGTH (value_type (regval)) - reg_offset; + + /* If the register length is larger than the number of bytes + remaining to copy, then only copy the appropriate bytes. */ + if (reg_len > len) + reg_len = len; + + value_contents_copy (value, offset, regval, reg_offset, reg_len); + + offset += reg_len; + len -= reg_len; + reg_offset = 0; + regnum++; + } +} + /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME. */ struct value * @@ -616,6 +704,8 @@ value_from_register (struct type *type, int regnum, struct frame_info *frame) if (gdbarch_convert_register_p (gdbarch, regnum, type1)) { + int optim, unavail, ok; + /* The ISA/ABI need to something weird when obtaining the specified value from this register. It might need to re-order non-adjacent, starting with REGNUM (see MIPS and @@ -627,36 +717,81 @@ value_from_register (struct type *type, int regnum, struct frame_info *frame) VALUE_LVAL (v) = lval_register; VALUE_FRAME_ID (v) = get_frame_id (frame); VALUE_REGNUM (v) = regnum; - gdbarch_register_to_value (gdbarch, - frame, regnum, type1, value_contents_raw (v)); + ok = gdbarch_register_to_value (gdbarch, frame, regnum, type1, + value_contents_raw (v), &optim, + &unavail); + + if (!ok) + { + if (optim) + mark_value_bytes_optimized_out (v, 0, TYPE_LENGTH (type)); + if (unavail) + mark_value_bytes_unavailable (v, 0, TYPE_LENGTH (type)); + } } else { - int len = TYPE_LENGTH (type); - /* Construct the value. */ - v = gdbarch_value_from_register (gdbarch, type, regnum, frame); + v = gdbarch_value_from_register (gdbarch, type, + regnum, get_frame_id (frame)); /* Get the data. */ - if (!get_frame_register_bytes (frame, regnum, value_offset (v), len, - value_contents_raw (v))) - set_value_optimized_out (v, 1); + read_frame_register_value (v, frame); } + return v; } -/* Return contents of register REGNUM in frame FRAME as address, - interpreted as value of type TYPE. Will abort if register - value is not available. */ +/* Return contents of register REGNUM in frame FRAME as address. + Will abort if register value is not available. */ CORE_ADDR -address_from_register (struct type *type, int regnum, struct frame_info *frame) +address_from_register (int regnum, struct frame_info *frame) { + struct gdbarch *gdbarch = get_frame_arch (frame); + struct type *type = builtin_type (gdbarch)->builtin_data_ptr; struct value *value; CORE_ADDR result; - value = value_from_register (type, regnum, frame); - gdb_assert (value); + /* This routine may be called during early unwinding, at a time + where the ID of FRAME is not yet known. Calling value_from_register + would therefore abort in get_frame_id. However, since we only need + a temporary value that is never used as lvalue, we actually do not + really need to set its VALUE_FRAME_ID. Therefore, we re-implement + the core of value_from_register, but use the null_frame_id. */ + + /* Some targets require a special conversion routine even for plain + pointer types. Avoid constructing a value object in those cases. */ + if (gdbarch_convert_register_p (gdbarch, regnum, type)) + { + gdb_byte *buf = alloca (TYPE_LENGTH (type)); + int optim, unavail, ok; + + ok = gdbarch_register_to_value (gdbarch, frame, regnum, type, + buf, &optim, &unavail); + if (!ok) + { + /* This function is used while computing a location expression. + Complain about the value being optimized out, rather than + letting value_as_address complain about some random register + the expression depends on not being saved. */ + error_value_optimized_out (); + } + + return unpack_long (type, buf); + } + + value = gdbarch_value_from_register (gdbarch, type, regnum, null_frame_id); + read_frame_register_value (value, frame); + + if (value_optimized_out (value)) + { + /* This function is used while computing a location expression. + Complain about the value being optimized out, rather than + letting value_as_address complain about some random register + the expression depends on not being saved. */ + error_value_optimized_out (); + } result = value_as_address (value); release_value (value); @@ -664,3 +799,4 @@ address_from_register (struct type *type, int regnum, struct frame_info *frame) return result; } +