From ca45ab26f53023cab527eae940de86af4d03aa47 Mon Sep 17 00:00:00 2001 From: Victor Kamensky Date: Sun, 2 Nov 2014 13:28:35 -0800 Subject: [PATCH] read_pieced_value do big endian processing only in case of valid gdb_regnum During armv7b testing gdb.base/store.exp test was failling with 'GDB internal error' with the following message: Temporary breakpoint 1, wack_double (u= ../../binutils-gdb/gdb/regcache.c:177: internal-error: register_size: Assertion `regnum >= 0 && regnum < (gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch))' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. It turns out that compiler generated DWARF with non-existent register numbers. The compiler issue is present in both little endian (armv7) and big endian (armv7b) (it is separate issue). Here is example for one of formal parameters of wack_double function: <2><792>: Abbrev Number: 10 (DW_TAG_formal_parameter) <793> DW_AT_name : u <795> DW_AT_decl_file : 1 <796> DW_AT_decl_line : 115 <797> DW_AT_type : <0x57c> <79b> DW_AT_location : 6 byte block: 6d 93 4 6c 93 4 (DW_OP_reg29 (r29); DW_OP_piece: 4; DW_OP_reg28 (r28); DW_OP_piece: 4) In both big and little endian cases gdbarch_dwarf2_reg_to_regnum returns -1 which is stored into gdb_regnum. But it causes severe problem only in big endian case because in read_pieced_value and write_pieced_value functions BFD_ENDIAN_BIG related processing happen regardless of gdb_regnum value, for example register_size function is called and in case of gdb_regnum=-1, it cause 'GDB internal error' and crash. Solution is to move BFD_ENDIAN_BIG related processing under (gdb_regnum != -1) branch of processing. gdb/ChangeLog: 2014-11-02 Victor Kamensky * dwarf2loc.c (read_pieced_value): Do big endian processing only if gdb_regnum is not -1. (write_pieced_value): Ditto. --- gdb/dwarf2loc.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c index 71adc896e99..6e461bcdccf 100644 --- a/gdb/dwarf2loc.c +++ b/gdb/dwarf2loc.c @@ -1683,21 +1683,21 @@ read_pieced_value (struct value *v) { struct gdbarch *arch = get_frame_arch (frame); int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno); - int reg_offset = source_offset; - - if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG - && this_size < register_size (arch, gdb_regnum)) - { - /* Big-endian, and we want less than full size. */ - reg_offset = register_size (arch, gdb_regnum) - this_size; - /* We want the lower-order THIS_SIZE_BITS of the bytes - we extract from the register. */ - source_offset_bits += 8 * this_size - this_size_bits; - } if (gdb_regnum != -1) { int optim, unavail; + int reg_offset = source_offset; + + if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG + && this_size < register_size (arch, gdb_regnum)) + { + /* Big-endian, and we want less than full size. */ + reg_offset = register_size (arch, gdb_regnum) - this_size; + /* We want the lower-order THIS_SIZE_BITS of the bytes + we extract from the register. */ + source_offset_bits += 8 * this_size - this_size_bits; + } if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset, this_size, buffer, @@ -1875,15 +1875,18 @@ write_pieced_value (struct value *to, struct value *from) { struct gdbarch *arch = get_frame_arch (frame); int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno); - int reg_offset = dest_offset; - - if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG - && this_size <= register_size (arch, gdb_regnum)) - /* Big-endian, and we want less than full size. */ - reg_offset = register_size (arch, gdb_regnum) - this_size; if (gdb_regnum != -1) { + int reg_offset = dest_offset; + + if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG + && this_size <= register_size (arch, gdb_regnum)) + { + /* Big-endian, and we want less than full size. */ + reg_offset = register_size (arch, gdb_regnum) - this_size; + } + if (need_bitwise) { int optim, unavail; -- 2.30.2