diff options
author | Stan Shebs <shebs@codesourcery.com> | 2010-04-20 18:52:59 +0000 |
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committer | Stan Shebs <shebs@codesourcery.com> | 2010-04-20 18:52:59 +0000 |
commit | 08922a10505b89e293906fbbd94d403b29f7aed9 (patch) | |
tree | 3663dcc9b7fb391ff59f67c19ec9092f528f7114 /gdb/dwarf2loc.c | |
parent | 2dc7f7b33b425c6c19078f29e4e8c9e0ddca41e6 (diff) | |
download | gdb-08922a10505b89e293906fbbd94d403b29f7aed9.zip gdb-08922a10505b89e293906fbbd94d403b29f7aed9.tar.gz gdb-08922a10505b89e293906fbbd94d403b29f7aed9.tar.bz2 |
2010-04-20 Stan Shebs <stan@codesourcery.com>
Nathan Sidwell <nathan@codesourcery.com>
* dwarf2loc.c (struct axs_var_loc): New struct.
(dwarf2_tracepoint_var_loc): New function.
(dwarf2_tracepoint_var_access): New function.
(dwarf2_tracepoint_var_ref): Use dwarf2_tracepoint_var_loc, deal
with DW_OP_piece.
(locexpr_describe_location_piece): New function.
(locexpr_describe_location_1): New function.
(locexpr_describe_location): Call it, update signature.
(loclist_describe_location): Rewrite to loop over locations,
update signature.
* symtab.h (struct symbol_computed_ops): Add address to
describe_location arguments, return void.
* printcmd.c (address_info): Get context PC, pass to computed
location description.
* tracepoint.c (scope_info): Ditto.
* ax-gdb.c (trace_kludge): Export.
Diffstat (limited to 'gdb/dwarf2loc.c')
-rw-r--r-- | gdb/dwarf2loc.c | 553 |
1 files changed, 463 insertions, 90 deletions
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index ed7dfb9..8fbf651 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -614,28 +614,47 @@ dwarf2_loc_desc_needs_frame (gdb_byte *data, unsigned short size, return baton.needs_frame || in_reg; } -static void -dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, - struct agent_expr *ax, struct axs_value *value, - gdb_byte *data, int size) +/* This struct keeps track of the pieces that make up a multi-location + object, for use in agent expression generation. It is + superficially similar to struct dwarf_expr_piece, but + dwarf_expr_piece is designed for use in immediate evaluation, and + does not, for example, have a way to record both base register and + offset. */ + +struct axs_var_loc { - if (!data || size == 0) - { - value->optimized_out = 1; - } - else if (size == 1 - && data[0] >= DW_OP_reg0 - && data[0] <= DW_OP_reg31) + /* Memory vs register, etc */ + enum axs_lvalue_kind kind; + + /* If non-zero, number of bytes in this fragment */ + unsigned bytes; + + /* (GDB-numbered) reg, or base reg if >= 0 */ + int reg; + + /* offset from reg */ + LONGEST offset; +}; + +static gdb_byte * +dwarf2_tracepoint_var_loc (struct symbol *symbol, + struct agent_expr *ax, + struct axs_var_loc *loc, + struct gdbarch *gdbarch, + gdb_byte *data, gdb_byte *end) +{ + if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) { - value->kind = axs_lvalue_register; - value->u.reg = data[0] - DW_OP_reg0; + loc->kind = axs_lvalue_register; + loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); + data += 1; } else if (data[0] == DW_OP_regx) { ULONGEST reg; - read_uleb128 (data + 1, data + size, ®); - value->kind = axs_lvalue_register; - value->u.reg = reg; + data = read_uleb128 (data + 1, end, ®); + loc->kind = axs_lvalue_register; + loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); } else if (data[0] == DW_OP_fbreg) { @@ -643,7 +662,6 @@ dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, struct symbol *framefunc; int frame_reg = 0; LONGEST frame_offset; - gdb_byte *buf_end; gdb_byte *base_data; size_t base_size; LONGEST base_offset = 0; @@ -661,57 +679,202 @@ dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, dwarf_expr_frame_base_1 (framefunc, ax->scope, &base_data, &base_size); - if (base_data[0] >= DW_OP_breg0 - && base_data[0] <= DW_OP_breg31) + if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) { + gdb_byte *buf_end; + frame_reg = base_data[0] - DW_OP_breg0; - buf_end = read_sleb128 (base_data + 1, base_data + base_size, &base_offset); + buf_end = read_sleb128 (base_data + 1, + base_data + base_size, &base_offset); if (buf_end != base_data + base_size) error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), frame_reg, SYMBOL_PRINT_NAME (symbol)); } + else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) + { + /* The frame base is just the register, with no offset. */ + frame_reg = base_data[0] - DW_OP_reg0; + base_offset = 0; + } else { /* We don't know what to do with the frame base expression, so we can't trace this variable; give up. */ - error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled"), - SYMBOL_PRINT_NAME (symbol)); + error (_("Cannot generate expression to collect symbol \"%s\"; DWARF 2 encoding not handled, first opcode in base data is 0x%x."), + SYMBOL_PRINT_NAME (symbol), base_data[0]); } - buf_end = read_sleb128 (data + 1, data + size, &frame_offset); - if (buf_end != data + size) - error (_("Unexpected opcode after DW_OP_fbreg for symbol \"%s\"."), - SYMBOL_PRINT_NAME (symbol)); - - ax_reg (ax, frame_reg); - ax_const_l (ax, base_offset + frame_offset); - ax_simple (ax, aop_add); + data = read_sleb128 (data + 1, end, &frame_offset); - value->kind = axs_lvalue_memory; + loc->kind = axs_lvalue_memory; + loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); + loc->offset = base_offset + frame_offset; } - else if (data[0] >= DW_OP_breg0 - && data[0] <= DW_OP_breg31) + else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) { unsigned int reg; LONGEST offset; - gdb_byte *buf_end; reg = data[0] - DW_OP_breg0; - buf_end = read_sleb128 (data + 1, data + size, &offset); - if (buf_end != data + size) - error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), - reg, SYMBOL_PRINT_NAME (symbol)); + data = read_sleb128 (data + 1, end, &offset); - ax_reg (ax, reg); - ax_const_l (ax, offset); - ax_simple (ax, aop_add); - - value->kind = axs_lvalue_memory; + loc->kind = axs_lvalue_memory; + loc->reg = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); + loc->offset = offset; } else error (_("Unsupported DWARF opcode 0x%x in the location of \"%s\"."), data[0], SYMBOL_PRINT_NAME (symbol)); + + return data; } + +/* Given the location of a piece, issue bytecodes that will access it. */ + +static void +dwarf2_tracepoint_var_access (struct agent_expr *ax, + struct axs_value *value, + struct axs_var_loc *loc) +{ + value->kind = loc->kind; + + switch (loc->kind) + { + case axs_lvalue_register: + value->u.reg = loc->reg; + break; + + case axs_lvalue_memory: + ax_reg (ax, loc->reg); + if (loc->offset) + { + ax_const_l (ax, loc->offset); + ax_simple (ax, aop_add); + } + break; + + default: + internal_error (__FILE__, __LINE__, _("Unhandled value kind in dwarf2_tracepoint_var_access")); + } +} + +static void +dwarf2_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, + struct agent_expr *ax, struct axs_value *value, + gdb_byte *data, int size) +{ + gdb_byte *end = data + size; + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + /* In practice, a variable is not going to be spread across + dozens of registers or memory locations. If someone comes up + with a real-world example, revisit this. */ +#define MAX_FRAGS 16 + struct axs_var_loc fragments[MAX_FRAGS]; + int nfrags = 0, frag; + int length = 0; + int piece_ok = 0; + int bad = 0; + int first = 1; + + if (!data || size == 0) + { + value->optimized_out = 1; + return; + } + + while (data < end) + { + if (!piece_ok) + { + if (nfrags == MAX_FRAGS) + error (_("Too many pieces in location for \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + fragments[nfrags].bytes = 0; + data = dwarf2_tracepoint_var_loc (symbol, ax, &fragments[nfrags], + gdbarch, data, end); + nfrags++; + piece_ok = 1; + } + else if (data[0] == DW_OP_piece) + { + ULONGEST bytes; + + data = read_uleb128 (data + 1, end, &bytes); + /* Only deal with 4 byte fragments for now. */ + if (bytes != 4) + error (_("DW_OP_piece %s not supported in location for \"%s\"."), + pulongest (bytes), SYMBOL_PRINT_NAME (symbol)); + fragments[nfrags - 1].bytes = bytes; + length += bytes; + piece_ok = 0; + } + else + { + bad = 1; + break; + } + } + + if (bad || data > end) + error (_("Corrupted DWARF expression for \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + /* If single expression, no pieces, convert to external format. */ + if (length == 0) + { + dwarf2_tracepoint_var_access (ax, value, &fragments[0]); + return; + } + + if (length != TYPE_LENGTH (value->type)) + error (_("Inconsistent piece information for \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + /* Emit bytecodes to assemble the pieces into a single stack entry. */ + + for ((frag = (byte_order == BFD_ENDIAN_BIG ? 0 : nfrags - 1)); + nfrags--; + (frag += (byte_order == BFD_ENDIAN_BIG ? 1 : -1))) + { + if (!first) + { + /* shift the previous fragment up 32 bits */ + ax_const_l (ax, 32); + ax_simple (ax, aop_lsh); + } + + dwarf2_tracepoint_var_access (ax, value, &fragments[frag]); + + switch (value->kind) + { + case axs_lvalue_register: + ax_reg (ax, value->u.reg); + break; + + case axs_lvalue_memory: + { + extern int trace_kludge; /* Ugh. */ + + gdb_assert (fragments[frag].bytes == 4); + if (trace_kludge) + ax_trace_quick (ax, 4); + ax_simple (ax, aop_ref32); + } + break; + } + + if (!first) + { + /* or the new fragment into the previous */ + ax_zero_ext (ax, 32); + ax_simple (ax, aop_bit_or); + } + first = 0; + } + value->kind = axs_rvalue; +} + /* Return the value of SYMBOL in FRAME using the DWARF-2 expression evaluator to calculate the location. */ @@ -735,26 +898,104 @@ locexpr_read_needs_frame (struct symbol *symbol) dlbaton->per_cu); } -/* Print a natural-language description of SYMBOL to STREAM. */ -static int -locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) +/* Describe a single piece of a location, returning an updated + position in the bytecode sequence. */ + +static gdb_byte * +locexpr_describe_location_piece (struct symbol *symbol, struct ui_file *stream, + CORE_ADDR addr, struct objfile *objfile, + gdb_byte *data, int size, unsigned int addr_size) { - /* FIXME: be more extensive. */ - struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); - int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); + struct gdbarch *gdbarch = get_objfile_arch (objfile); + int regno; + + if (data[0] >= DW_OP_reg0 && data[0] <= DW_OP_reg31) + { + regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_reg0); + fprintf_filtered (stream, _("a variable in $%s"), + gdbarch_register_name (gdbarch, regno)); + data += 1; + } + else if (data[0] == DW_OP_regx) + { + ULONGEST reg; - if (dlbaton->size == 1 - && dlbaton->data[0] >= DW_OP_reg0 - && dlbaton->data[0] <= DW_OP_reg31) + data = read_uleb128 (data + 1, data + size, ®); + regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); + fprintf_filtered (stream, _("a variable in $%s"), + gdbarch_register_name (gdbarch, regno)); + } + else if (data[0] == DW_OP_fbreg) { - struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); - struct gdbarch *gdbarch = get_objfile_arch (objfile); - int regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, - dlbaton->data[0] - DW_OP_reg0); + struct block *b; + struct symbol *framefunc; + int frame_reg = 0; + LONGEST frame_offset; + gdb_byte *base_data; + size_t base_size; + LONGEST base_offset = 0; + + b = block_for_pc (addr); + + if (!b) + error (_("No block found for address for symbol \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + framefunc = block_linkage_function (b); + + if (!framefunc) + error (_("No function found for block for symbol \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + dwarf_expr_frame_base_1 (framefunc, addr, &base_data, &base_size); + + if (base_data[0] >= DW_OP_breg0 && base_data[0] <= DW_OP_breg31) + { + gdb_byte *buf_end; + + frame_reg = base_data[0] - DW_OP_breg0; + buf_end = read_sleb128 (base_data + 1, + base_data + base_size, &base_offset); + if (buf_end != base_data + base_size) + error (_("Unexpected opcode after DW_OP_breg%u for symbol \"%s\"."), + frame_reg, SYMBOL_PRINT_NAME (symbol)); + } + else if (base_data[0] >= DW_OP_reg0 && base_data[0] <= DW_OP_reg31) + { + /* The frame base is just the register, with no offset. */ + frame_reg = base_data[0] - DW_OP_reg0; + base_offset = 0; + } + else + { + /* We don't know what to do with the frame base expression, + so we can't trace this variable; give up. */ + error (_("Cannot describe location of symbol \"%s\"; " + "DWARF 2 encoding not handled, " + "first opcode in base data is 0x%x."), + SYMBOL_PRINT_NAME (symbol), base_data[0]); + } + + regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, frame_reg); + + data = read_sleb128 (data + 1, data + size, &frame_offset); + + fprintf_filtered (stream, _("a variable at frame base reg $%s offset %s+%s"), + gdbarch_register_name (gdbarch, regno), + plongest (base_offset), plongest (frame_offset)); + } + else if (data[0] >= DW_OP_breg0 && data[0] <= DW_OP_breg31) + { + LONGEST offset; + + regno = gdbarch_dwarf2_reg_to_regnum (gdbarch, data[0] - DW_OP_breg0); + + data = read_sleb128 (data + 1, data + size, &offset); + fprintf_filtered (stream, - "a variable in register %s", + _("a variable at offset %s from base reg $%s"), + plongest (offset), gdbarch_register_name (gdbarch, regno)); - return 1; } /* The location expression for a TLS variable looks like this (on a @@ -769,37 +1010,93 @@ locexpr_describe_location (struct symbol *symbol, struct ui_file *stream) The operand represents the offset at which the variable is within the thread local storage. */ - if (dlbaton->size > 1 - && dlbaton->data[dlbaton->size - 1] == DW_OP_GNU_push_tls_address) - if (dlbaton->data[0] == DW_OP_addr) - { - struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); - struct gdbarch *gdbarch = get_objfile_arch (objfile); - CORE_ADDR offset = dwarf2_read_address (gdbarch, - &dlbaton->data[1], - &dlbaton->data[dlbaton->size - 1], - addr_size); - fprintf_filtered (stream, - "a thread-local variable at offset %s in the " - "thread-local storage for `%s'", - paddress (gdbarch, offset), objfile->name); - return 1; - } - + else if (size > 1 + && data[size - 1] == DW_OP_GNU_push_tls_address + && data[0] == DW_OP_addr) + { + CORE_ADDR offset = dwarf2_read_address (gdbarch, + data + 1, + data + size - 1, + addr_size); + fprintf_filtered (stream, + _("a thread-local variable at offset %s " + "in the thread-local storage for `%s'"), + paddress (gdbarch, offset), objfile->name); + + data += 1 + addr_size + 1; + } + else + fprintf_filtered (stream, + _("a variable with complex or multiple locations (DWARF2)")); - fprintf_filtered (stream, - "a variable with complex or multiple locations (DWARF2)"); - return 1; + return data; } +/* Describe a single location, which may in turn consist of multiple + pieces. */ -/* Describe the location of SYMBOL as an agent value in VALUE, generating - any necessary bytecode in AX. +static void +locexpr_describe_location_1 (struct symbol *symbol, CORE_ADDR addr, + struct ui_file *stream, gdb_byte *data, int size, + struct objfile *objfile, unsigned int addr_size) +{ + gdb_byte *end = data + size; + int piece_done = 0, first_piece = 1, bad = 0; + + /* A multi-piece description consists of multiple sequences of bytes + each followed by DW_OP_piece + length of piece. */ + while (data < end) + { + if (!piece_done) + { + if (first_piece) + first_piece = 0; + else + fprintf_filtered (stream, _(", and ")); + + data = locexpr_describe_location_piece (symbol, stream, addr, objfile, + data, size, addr_size); + piece_done = 1; + } + else if (data[0] == DW_OP_piece) + { + ULONGEST bytes; + + data = read_uleb128 (data + 1, end, &bytes); + + fprintf_filtered (stream, _(" [%s-byte piece]"), pulongest (bytes)); + + piece_done = 0; + } + else + { + bad = 1; + break; + } + } + + if (bad || data > end) + error (_("Corrupted DWARF2 expression for \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); +} + +/* Print a natural-language description of SYMBOL to STREAM. This + version is for a symbol with a single location. */ - NOTE drow/2003-02-26: This function is extremely minimal, because - doing it correctly is extremely complicated and there is no - publicly available stub with tracepoint support for me to test - against. When there is one this function should be revisited. */ +static void +locexpr_describe_location (struct symbol *symbol, CORE_ADDR addr, + struct ui_file *stream) +{ + struct dwarf2_locexpr_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); + struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); + unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); + + locexpr_describe_location_1 (symbol, addr, stream, dlbaton->data, dlbaton->size, + objfile, addr_size); +} + +/* Describe the location of SYMBOL as an agent value in VALUE, generating + any necessary bytecode in AX. */ static void locexpr_tracepoint_var_ref (struct symbol *symbol, struct gdbarch *gdbarch, @@ -863,13 +1160,89 @@ loclist_read_needs_frame (struct symbol *symbol) return 1; } -/* Print a natural-language description of SYMBOL to STREAM. */ -static int -loclist_describe_location (struct symbol *symbol, struct ui_file *stream) +/* Print a natural-language description of SYMBOL to STREAM. This + version applies when there is a list of different locations, each + with a specified address range. */ + +static void +loclist_describe_location (struct symbol *symbol, CORE_ADDR addr, + struct ui_file *stream) { - /* FIXME: Could print the entire list of locations. */ - fprintf_filtered (stream, "a variable with multiple locations"); - return 1; + struct dwarf2_loclist_baton *dlbaton = SYMBOL_LOCATION_BATON (symbol); + CORE_ADDR low, high; + gdb_byte *loc_ptr, *buf_end; + int length, first = 1; + struct objfile *objfile = dwarf2_per_cu_objfile (dlbaton->per_cu); + struct gdbarch *gdbarch = get_objfile_arch (objfile); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu); + CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1)); + /* Adjust base_address for relocatable objects. */ + CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets, + SECT_OFF_TEXT (objfile)); + CORE_ADDR base_address = dlbaton->base_address + base_offset; + + loc_ptr = dlbaton->data; + buf_end = dlbaton->data + dlbaton->size; + + fprintf_filtered (stream, _("multi-location (")); + + /* Iterate through locations until we run out. */ + while (1) + { + if (buf_end - loc_ptr < 2 * addr_size) + error (_("Corrupted DWARF expression for symbol \"%s\"."), + SYMBOL_PRINT_NAME (symbol)); + + low = extract_unsigned_integer (loc_ptr, addr_size, byte_order); + loc_ptr += addr_size; + + /* A base-address-selection entry. */ + if (low == base_mask) + { + base_address = dwarf2_read_address (gdbarch, + loc_ptr, buf_end, addr_size); + fprintf_filtered (stream, _("[base address %s]"), + paddress (gdbarch, base_address)); + loc_ptr += addr_size; + continue; + } + + high = extract_unsigned_integer (loc_ptr, addr_size, byte_order); + loc_ptr += addr_size; + + /* An end-of-list entry. */ + if (low == 0 && high == 0) + { + /* Indicate the end of the list, for readability. */ + fprintf_filtered (stream, _(")")); + return; + } + + /* Otherwise, a location expression entry. */ + low += base_address; + high += base_address; + + length = extract_unsigned_integer (loc_ptr, 2, byte_order); + loc_ptr += 2; + + /* Separate the different locations with a semicolon. */ + if (first) + first = 0; + else + fprintf_filtered (stream, _("; ")); + + /* (It would improve readability to print only the minimum + necessary digits of the second number of the range.) */ + fprintf_filtered (stream, _("range %s-%s, "), + paddress (gdbarch, low), paddress (gdbarch, high)); + + /* Now describe this particular location. */ + locexpr_describe_location_1 (symbol, low, stream, loc_ptr, length, + objfile, addr_size); + + loc_ptr += length; + } } /* Describe the location of SYMBOL as an agent value in VALUE, generating |