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      1 
      2 /*--------------------------------------------------------------------*/
      3 /*--- Basic definitions and helper functions for DWARF3.           ---*/
      4 /*---                                                   d3basics.c ---*/
      5 /*--------------------------------------------------------------------*/
      6 
      7 /*
      8    This file is part of Valgrind, a dynamic binary instrumentation
      9    framework.
     10 
     11    Copyright (C) 2008-2012 OpenWorks LLP
     12       info (at) open-works.co.uk
     13 
     14    This program is free software; you can redistribute it and/or
     15    modify it under the terms of the GNU General Public License as
     16    published by the Free Software Foundation; either version 2 of the
     17    License, or (at your option) any later version.
     18 
     19    This program is distributed in the hope that it will be useful, but
     20    WITHOUT ANY WARRANTY; without even the implied warranty of
     21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     22    General Public License for more details.
     23 
     24    You should have received a copy of the GNU General Public License
     25    along with this program; if not, write to the Free Software
     26    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
     27    02111-1307, USA.
     28 
     29    The GNU General Public License is contained in the file COPYING.
     30 
     31    Neither the names of the U.S. Department of Energy nor the
     32    University of California nor the names of its contributors may be
     33    used to endorse or promote products derived from this software
     34    without prior written permission.
     35 */
     36 
     37 #include "pub_core_basics.h"
     38 #include "pub_core_debuginfo.h"
     39 #include "pub_core_libcassert.h"
     40 #include "pub_core_libcprint.h"
     41 #include "pub_core_options.h"
     42 #include "pub_core_xarray.h"
     43 
     44 #include "pub_core_vki.h"       /* VKI_PROT_READ */
     45 #include "pub_core_aspacemgr.h" /* VG_(is_valid_for_client) */
     46 
     47 #include "priv_misc.h"
     48 #include "priv_d3basics.h"      /* self */
     49 #include "priv_storage.h"
     50 
     51 HChar* ML_(pp_DW_children) ( DW_children hashch )
     52 {
     53    switch (hashch) {
     54       case DW_children_no:  return "no children";
     55       case DW_children_yes: return "has children";
     56    }
     57    return "DW_children_???";
     58 }
     59 
     60 HChar* ML_(pp_DW_TAG) ( DW_TAG tag )
     61 {
     62    switch (tag) {
     63       case DW_TAG_padding:            return "DW_TAG_padding";
     64       case DW_TAG_array_type:         return "DW_TAG_array_type";
     65       case DW_TAG_class_type:         return "DW_TAG_class_type";
     66       case DW_TAG_entry_point:        return "DW_TAG_entry_point";
     67       case DW_TAG_enumeration_type:   return "DW_TAG_enumeration_type";
     68       case DW_TAG_formal_parameter:   return "DW_TAG_formal_parameter";
     69       case DW_TAG_imported_declaration:
     70          return "DW_TAG_imported_declaration";
     71       case DW_TAG_label:              return "DW_TAG_label";
     72       case DW_TAG_lexical_block:      return "DW_TAG_lexical_block";
     73       case DW_TAG_member:             return "DW_TAG_member";
     74       case DW_TAG_pointer_type:       return "DW_TAG_pointer_type";
     75       case DW_TAG_reference_type:     return "DW_TAG_reference_type";
     76       case DW_TAG_compile_unit:       return "DW_TAG_compile_unit";
     77       case DW_TAG_string_type:        return "DW_TAG_string_type";
     78       case DW_TAG_structure_type:     return "DW_TAG_structure_type";
     79       case DW_TAG_subroutine_type:    return "DW_TAG_subroutine_type";
     80       case DW_TAG_typedef:            return "DW_TAG_typedef";
     81       case DW_TAG_union_type:         return "DW_TAG_union_type";
     82       case DW_TAG_unspecified_parameters:
     83          return "DW_TAG_unspecified_parameters";
     84       case DW_TAG_variant:            return "DW_TAG_variant";
     85       case DW_TAG_common_block:       return "DW_TAG_common_block";
     86       case DW_TAG_common_inclusion:   return "DW_TAG_common_inclusion";
     87       case DW_TAG_inheritance:        return "DW_TAG_inheritance";
     88       case DW_TAG_inlined_subroutine:
     89          return "DW_TAG_inlined_subroutine";
     90       case DW_TAG_module:             return "DW_TAG_module";
     91       case DW_TAG_ptr_to_member_type: return "DW_TAG_ptr_to_member_type";
     92       case DW_TAG_set_type:           return "DW_TAG_set_type";
     93       case DW_TAG_subrange_type:      return "DW_TAG_subrange_type";
     94       case DW_TAG_with_stmt:          return "DW_TAG_with_stmt";
     95       case DW_TAG_access_declaration: return "DW_TAG_access_declaration";
     96       case DW_TAG_base_type:          return "DW_TAG_base_type";
     97       case DW_TAG_catch_block:        return "DW_TAG_catch_block";
     98       case DW_TAG_const_type:         return "DW_TAG_const_type";
     99       case DW_TAG_constant:           return "DW_TAG_constant";
    100       case DW_TAG_enumerator:         return "DW_TAG_enumerator";
    101       case DW_TAG_file_type:          return "DW_TAG_file_type";
    102       case DW_TAG_friend:             return "DW_TAG_friend";
    103       case DW_TAG_namelist:           return "DW_TAG_namelist";
    104       case DW_TAG_namelist_item:      return "DW_TAG_namelist_item";
    105       case DW_TAG_packed_type:        return "DW_TAG_packed_type";
    106       case DW_TAG_subprogram:         return "DW_TAG_subprogram";
    107       case DW_TAG_template_type_param:
    108          return "DW_TAG_template_type_param";
    109       case DW_TAG_template_value_param:
    110          return "DW_TAG_template_value_param";
    111       case DW_TAG_thrown_type:        return "DW_TAG_thrown_type";
    112       case DW_TAG_try_block:          return "DW_TAG_try_block";
    113       case DW_TAG_variant_part:       return "DW_TAG_variant_part";
    114       case DW_TAG_variable:           return "DW_TAG_variable";
    115       case DW_TAG_volatile_type:      return "DW_TAG_volatile_type";
    116       /* DWARF 3.  */
    117       case DW_TAG_dwarf_procedure:    return "DW_TAG_dwarf_procedure";
    118       case DW_TAG_restrict_type:      return "DW_TAG_restrict_type";
    119       case DW_TAG_interface_type:     return "DW_TAG_interface_type";
    120       case DW_TAG_namespace:          return "DW_TAG_namespace";
    121       case DW_TAG_imported_module:    return "DW_TAG_imported_module";
    122       case DW_TAG_unspecified_type:   return "DW_TAG_unspecified_type";
    123       case DW_TAG_partial_unit:       return "DW_TAG_partial_unit";
    124       case DW_TAG_imported_unit:      return "DW_TAG_imported_unit";
    125       case DW_TAG_condition:          return "DW_TAG_condition";
    126       case DW_TAG_shared_type:        return "DW_TAG_shared_type";
    127       /* DWARF 4.  */
    128       case DW_TAG_type_unit:          return "DW_TAG_type_unit";
    129       case DW_TAG_rvalue_reference_type: return "DW_TAG_rvalue_reference_type";
    130       case DW_TAG_template_alias:     return "DW_TAG_template_alias";
    131       /* SGI/MIPS Extensions.  */
    132       case DW_TAG_MIPS_loop:          return "DW_TAG_MIPS_loop";
    133       /* HP extensions.  See:
    134          ftp://ftp.hp.com/pub/lang/tools/WDB/wdb-4.0.tar.gz .  */
    135       case DW_TAG_HP_array_descriptor:
    136          return "DW_TAG_HP_array_descriptor";
    137       /* GNU extensions.  */
    138       case DW_TAG_format_label:       return "DW_TAG_format_label";
    139       case DW_TAG_function_template:  return "DW_TAG_function_template";
    140       case DW_TAG_class_template:     return "DW_TAG_class_template";
    141       case DW_TAG_GNU_BINCL:          return "DW_TAG_GNU_BINCL";
    142       case DW_TAG_GNU_EINCL:          return "DW_TAG_GNU_EINCL";
    143       /* Extensions for UPC.  See: http://upc.gwu.edu/~upc.  */
    144       case DW_TAG_upc_shared_type:    return "DW_TAG_upc_shared_type";
    145       case DW_TAG_upc_strict_type:    return "DW_TAG_upc_strict_type";
    146       case DW_TAG_upc_relaxed_type:   return "DW_TAG_upc_relaxed_type";
    147       /* PGI (STMicroelectronics) extensions.  No documentation available.  */
    148       case DW_TAG_PGI_kanji_type:     return "DW_TAG_PGI_kanji_type";
    149       case DW_TAG_PGI_interface_block:
    150          return "DW_TAG_PGI_interface_block";
    151    }
    152    return "DW_TAG_???";
    153 }
    154 
    155 HChar* ML_(pp_DW_FORM) ( DW_FORM form )
    156 {
    157    switch (form) {
    158       case DW_FORM_addr:      return "DW_FORM_addr";
    159       case DW_FORM_block2:    return "DW_FORM_block2";
    160       case DW_FORM_block4:    return "DW_FORM_block4";
    161       case DW_FORM_data2:     return "DW_FORM_data2";
    162       case DW_FORM_data4:     return "DW_FORM_data4";
    163       case DW_FORM_data8:     return "DW_FORM_data8";
    164       case DW_FORM_string:    return "DW_FORM_string";
    165       case DW_FORM_block:     return "DW_FORM_block";
    166       case DW_FORM_block1:    return "DW_FORM_block1";
    167       case DW_FORM_data1:     return "DW_FORM_data1";
    168       case DW_FORM_flag:      return "DW_FORM_flag";
    169       case DW_FORM_sdata:     return "DW_FORM_sdata";
    170       case DW_FORM_strp:      return "DW_FORM_strp";
    171       case DW_FORM_udata:     return "DW_FORM_udata";
    172       case DW_FORM_ref_addr:  return "DW_FORM_ref_addr";
    173       case DW_FORM_ref1:      return "DW_FORM_ref1";
    174       case DW_FORM_ref2:      return "DW_FORM_ref2";
    175       case DW_FORM_ref4:      return "DW_FORM_ref4";
    176       case DW_FORM_ref8:      return "DW_FORM_ref8";
    177       case DW_FORM_ref_udata: return "DW_FORM_ref_udata";
    178       case DW_FORM_indirect:  return "DW_FORM_indirect";
    179       case DW_FORM_sec_offset:return "DW_FORM_sec_offset";
    180       case DW_FORM_exprloc:   return "DW_FORM_exprloc";
    181       case DW_FORM_flag_present:return "DW_FORM_flag_present";
    182       case DW_FORM_ref_sig8:  return "DW_FORM_ref_sig8";
    183       case DW_FORM_GNU_ref_alt:return "DW_FORM_GNU_ref_alt";
    184       case DW_FORM_GNU_strp_alt:return "DW_FORM_GNU_strp_alt";
    185    }
    186    return "DW_FORM_???";
    187 }
    188 
    189 HChar* ML_(pp_DW_AT) ( DW_AT attr )
    190 {
    191    switch (attr) {
    192       case DW_AT_sibling:             return "DW_AT_sibling";
    193       case DW_AT_location:            return "DW_AT_location";
    194       case DW_AT_name: return "DW_AT_name";
    195       case DW_AT_ordering: return "DW_AT_ordering";
    196       case DW_AT_subscr_data: return "DW_AT_subscr_data";
    197       case DW_AT_byte_size: return "DW_AT_byte_size";
    198       case DW_AT_bit_offset: return "DW_AT_bit_offset";
    199       case DW_AT_bit_size: return "DW_AT_bit_size";
    200       case DW_AT_element_list: return "DW_AT_element_list";
    201       case DW_AT_stmt_list: return "DW_AT_stmt_list";
    202       case DW_AT_low_pc: return "DW_AT_low_pc";
    203       case DW_AT_high_pc: return "DW_AT_high_pc";
    204       case DW_AT_language: return "DW_AT_language";
    205       case DW_AT_member: return "DW_AT_member";
    206       case DW_AT_discr: return "DW_AT_discr";
    207       case DW_AT_discr_value: return "DW_AT_discr_value";
    208       case DW_AT_visibility: return "DW_AT_visibility";
    209       case DW_AT_import: return "DW_AT_import";
    210       case DW_AT_string_length: return "DW_AT_string_length";
    211       case DW_AT_common_reference: return "DW_AT_common_reference";
    212       case DW_AT_comp_dir: return "DW_AT_comp_dir";
    213       case DW_AT_const_value: return "DW_AT_const_value";
    214       case DW_AT_containing_type: return "DW_AT_containing_type";
    215       case DW_AT_default_value: return "DW_AT_default_value";
    216       case DW_AT_inline: return "DW_AT_inline";
    217       case DW_AT_is_optional: return "DW_AT_is_optional";
    218       case DW_AT_lower_bound: return "DW_AT_lower_bound";
    219       case DW_AT_producer: return "DW_AT_producer";
    220       case DW_AT_prototyped: return "DW_AT_prototyped";
    221       case DW_AT_return_addr: return "DW_AT_return_addr";
    222       case DW_AT_start_scope: return "DW_AT_start_scope";
    223       case DW_AT_stride_size: return "DW_AT_stride_size";
    224       case DW_AT_upper_bound: return "DW_AT_upper_bound";
    225       case DW_AT_abstract_origin: return "DW_AT_abstract_origin";
    226       case DW_AT_accessibility: return "DW_AT_accessibility";
    227       case DW_AT_address_class: return "DW_AT_address_class";
    228       case DW_AT_artificial: return "DW_AT_artificial";
    229       case DW_AT_base_types: return "DW_AT_base_types";
    230       case DW_AT_calling_convention: return "DW_AT_calling_convention";
    231       case DW_AT_count: return "DW_AT_count";
    232       case DW_AT_data_member_location: return "DW_AT_data_member_location";
    233       case DW_AT_decl_column: return "DW_AT_decl_column";
    234       case DW_AT_decl_file: return "DW_AT_decl_file";
    235       case DW_AT_decl_line: return "DW_AT_decl_line";
    236       case DW_AT_declaration: return "DW_AT_declaration";
    237       case DW_AT_discr_list: return "DW_AT_discr_list";
    238       case DW_AT_encoding: return "DW_AT_encoding";
    239       case DW_AT_external: return "DW_AT_external";
    240       case DW_AT_frame_base: return "DW_AT_frame_base";
    241       case DW_AT_friend: return "DW_AT_friend";
    242       case DW_AT_identifier_case: return "DW_AT_identifier_case";
    243       case DW_AT_macro_info: return "DW_AT_macro_info";
    244       case DW_AT_namelist_items: return "DW_AT_namelist_items";
    245       case DW_AT_priority: return "DW_AT_priority";
    246       case DW_AT_segment: return "DW_AT_segment";
    247       case DW_AT_specification: return "DW_AT_specification";
    248       case DW_AT_static_link: return "DW_AT_static_link";
    249       case DW_AT_type: return "DW_AT_type";
    250       case DW_AT_use_location: return "DW_AT_use_location";
    251       case DW_AT_variable_parameter: return "DW_AT_variable_parameter";
    252       case DW_AT_virtuality: return "DW_AT_virtuality";
    253       case DW_AT_vtable_elem_location: return "DW_AT_vtable_elem_location";
    254       /* DWARF 3 values.  */
    255       case DW_AT_allocated: return "DW_AT_allocated";
    256       case DW_AT_associated: return "DW_AT_associated";
    257       case DW_AT_data_location: return "DW_AT_data_location";
    258       case DW_AT_stride: return "DW_AT_stride";
    259       case DW_AT_entry_pc: return "DW_AT_entry_pc";
    260       case DW_AT_use_UTF8: return "DW_AT_use_UTF8";
    261       case DW_AT_extension: return "DW_AT_extension";
    262       case DW_AT_ranges: return "DW_AT_ranges";
    263       case DW_AT_trampoline: return "DW_AT_trampoline";
    264       case DW_AT_call_column: return "DW_AT_call_column";
    265       case DW_AT_call_file: return "DW_AT_call_file";
    266       case DW_AT_call_line: return "DW_AT_call_line";
    267       case DW_AT_description: return "DW_AT_description";
    268       case DW_AT_binary_scale: return "DW_AT_binary_scale";
    269       case DW_AT_decimal_scale: return "DW_AT_decimal_scale";
    270       case DW_AT_small: return "DW_AT_small";
    271       case DW_AT_decimal_sign: return "DW_AT_decimal_sign";
    272       case DW_AT_digit_count: return "DW_AT_digit_count";
    273       case DW_AT_picture_string: return "DW_AT_picture_string";
    274       case DW_AT_mutable: return "DW_AT_mutable";
    275       case DW_AT_threads_scaled: return "DW_AT_threads_scaled";
    276       case DW_AT_explicit: return "DW_AT_explicit";
    277       case DW_AT_object_pointer: return "DW_AT_object_pointer";
    278       case DW_AT_endianity: return "DW_AT_endianity";
    279       case DW_AT_elemental: return "DW_AT_elemental";
    280       case DW_AT_pure: return "DW_AT_pure";
    281       case DW_AT_recursive: return "DW_AT_recursive";
    282       /* DWARF 4 values.  */
    283       case DW_AT_signature: return "DW_AT_signature";
    284       case DW_AT_main_subprogram: return "DW_AT_main_subprogram";
    285       case DW_AT_data_bit_offset: return "DW_AT_data_bit_offset";
    286       case DW_AT_const_expr: return "DW_AT_const_expr";
    287       case DW_AT_enum_class: return "DW_AT_enum_class";
    288       case DW_AT_linkage_name: return "DW_AT_linkage_name";
    289       /* SGI/MIPS extensions.  */
    290       /* case DW_AT_MIPS_fde: return "DW_AT_MIPS_fde"; */
    291       /* DW_AT_MIPS_fde == DW_AT_HP_unmodifiable */
    292       case DW_AT_MIPS_loop_begin: return "DW_AT_MIPS_loop_begin";
    293       case DW_AT_MIPS_tail_loop_begin: return "DW_AT_MIPS_tail_loop_begin";
    294       case DW_AT_MIPS_epilog_begin: return "DW_AT_MIPS_epilog_begin";
    295       case DW_AT_MIPS_loop_unroll_factor: return "DW_AT_MIPS_loop_unroll_factor";
    296       case DW_AT_MIPS_software_pipeline_depth: return "DW_AT_MIPS_software_pipeline_depth";
    297       case DW_AT_MIPS_linkage_name: return "DW_AT_MIPS_linkage_name";
    298       case DW_AT_MIPS_stride: return "DW_AT_MIPS_stride";
    299       case DW_AT_MIPS_abstract_name: return "DW_AT_MIPS_abstract_name";
    300       case DW_AT_MIPS_clone_origin: return "DW_AT_MIPS_clone_origin";
    301       case DW_AT_MIPS_has_inlines: return "DW_AT_MIPS_has_inlines";
    302       /* HP extensions.  */
    303       case DW_AT_HP_block_index: return "DW_AT_HP_block_index";
    304       case DW_AT_HP_unmodifiable: return "DW_AT_HP_unmodifiable";
    305       case DW_AT_HP_actuals_stmt_list: return "DW_AT_HP_actuals_stmt_list";
    306       case DW_AT_HP_proc_per_section: return "DW_AT_HP_proc_per_section";
    307       case DW_AT_HP_raw_data_ptr: return "DW_AT_HP_raw_data_ptr";
    308       case DW_AT_HP_pass_by_reference: return "DW_AT_HP_pass_by_reference";
    309       case DW_AT_HP_opt_level: return "DW_AT_HP_opt_level";
    310       case DW_AT_HP_prof_version_id: return "DW_AT_HP_prof_version_id";
    311       case DW_AT_HP_opt_flags: return "DW_AT_HP_opt_flags";
    312       case DW_AT_HP_cold_region_low_pc: return "DW_AT_HP_cold_region_low_pc";
    313       case DW_AT_HP_cold_region_high_pc: return "DW_AT_HP_cold_region_high_pc";
    314       case DW_AT_HP_all_variables_modifiable: return "DW_AT_HP_all_variables_modifiable";
    315       case DW_AT_HP_linkage_name: return "DW_AT_HP_linkage_name";
    316       case DW_AT_HP_prof_flags: return "DW_AT_HP_prof_flags";
    317       /* GNU extensions.  */
    318       case DW_AT_sf_names: return "DW_AT_sf_names";
    319       case DW_AT_src_info: return "DW_AT_src_info";
    320       case DW_AT_mac_info: return "DW_AT_mac_info";
    321       case DW_AT_src_coords: return "DW_AT_src_coords";
    322       case DW_AT_body_begin: return "DW_AT_body_begin";
    323       case DW_AT_body_end: return "DW_AT_body_end";
    324       case DW_AT_GNU_vector: return "DW_AT_GNU_vector";
    325       /* VMS extensions.  */
    326       case DW_AT_VMS_rtnbeg_pd_address: return "DW_AT_VMS_rtnbeg_pd_address";
    327       /* UPC extension.  */
    328       case DW_AT_upc_threads_scaled: return "DW_AT_upc_threads_scaled";
    329       /* PGI (STMicroelectronics) extensions.  */
    330       case DW_AT_PGI_lbase: return "DW_AT_PGI_lbase";
    331       case DW_AT_PGI_soffset: return "DW_AT_PGI_soffset";
    332       case DW_AT_PGI_lstride: return "DW_AT_PGI_lstride";
    333    }
    334    return "DW_AT_???";
    335 }
    336 
    337 
    338 /* ------ To do with evaluation of Dwarf expressions ------ */
    339 
    340 /* FIXME: duplicated in readdwarf.c */
    341 static
    342 ULong read_leb128 ( UChar* data, Int* length_return, Int sign )
    343 {
    344   ULong  result = 0;
    345   UInt   num_read = 0;
    346   Int    shift = 0;
    347   UChar  byte;
    348 
    349   vg_assert(sign == 0 || sign == 1);
    350 
    351   do
    352     {
    353       byte = * data ++;
    354       num_read ++;
    355 
    356       result |= ((ULong)(byte & 0x7f)) << shift;
    357 
    358       shift += 7;
    359 
    360     }
    361   while (byte & 0x80);
    362 
    363   if (length_return != NULL)
    364     * length_return = num_read;
    365 
    366   if (sign && (shift < 64) && (byte & 0x40))
    367     result |= -(1ULL << shift);
    368 
    369   return result;
    370 }
    371 
    372 /* Small helper functions easier to use
    373  * value is returned and the given pointer is
    374  * moved past end of leb128 data */
    375 /* FIXME: duplicated in readdwarf.c */
    376 static ULong read_leb128U( UChar **data )
    377 {
    378   Int len;
    379   ULong val = read_leb128( *data, &len, 0 );
    380   *data += len;
    381   return val;
    382 }
    383 
    384 /* Same for signed data */
    385 /* FIXME: duplicated in readdwarf.c */
    386 static Long read_leb128S( UChar **data )
    387 {
    388    Int len;
    389    ULong val = read_leb128( *data, &len, 1 );
    390    *data += len;
    391    return (Long)val;
    392 }
    393 
    394 /* FIXME: duplicates logic in readdwarf.c: copy_convert_CfiExpr_tree
    395    and {FP,SP}_REG decls */
    396 static Bool get_Dwarf_Reg( /*OUT*/Addr* a, Word regno, RegSummary* regs )
    397 {
    398    vg_assert(regs);
    399 #  if defined(VGP_x86_linux) || defined(VGP_x86_darwin)
    400    if (regno == 5/*EBP*/) { *a = regs->fp; return True; }
    401    if (regno == 4/*ESP*/) { *a = regs->sp; return True; }
    402 #  elif defined(VGP_amd64_linux) || defined(VGP_amd64_darwin)
    403    if (regno == 6/*RBP*/) { *a = regs->fp; return True; }
    404    if (regno == 7/*RSP*/) { *a = regs->sp; return True; }
    405 #  elif defined(VGP_ppc32_linux)
    406    if (regno == 1/*SP*/) { *a = regs->sp; return True; }
    407 #  elif defined(VGP_ppc64_linux)
    408    if (regno == 1/*SP*/) { *a = regs->sp; return True; }
    409 #  elif defined(VGP_arm_linux)
    410    if (regno == 13) { *a = regs->sp; return True; }
    411    if (regno == 11) { *a = regs->fp; return True; }
    412 #  elif defined(VGP_s390x_linux)
    413    if (regno == 15) { *a = regs->sp; return True; }
    414    if (regno == 11) { *a = regs->fp; return True; }
    415 #  elif defined(VGP_mips32_linux)
    416    if (regno == 29) { *a = regs->sp; return True; }
    417    if (regno == 30) { *a = regs->fp; return True; }
    418 #  else
    419 #    error "Unknown platform"
    420 #  endif
    421    return False;
    422 }
    423 
    424 /* Convert a stated address to an actual address */
    425 static Bool bias_address( Addr* a, const DebugInfo* di )
    426 {
    427    if (di->text_present
    428        && di->text_size > 0
    429        && *a >= di->text_debug_svma && *a < di->text_debug_svma + di->text_size) {
    430       *a += di->text_debug_bias;
    431    }
    432    else if (di->data_present
    433             && di->data_size > 0
    434             && *a >= di->data_debug_svma && *a < di->data_debug_svma + di->data_size) {
    435       *a += di->data_debug_bias;
    436    }
    437    else if (di->sdata_present
    438             && di->sdata_size > 0
    439             && *a >= di->sdata_debug_svma && *a < di->sdata_debug_svma + di->sdata_size) {
    440       *a += di->sdata_debug_bias;
    441    }
    442    else if (di->rodata_present
    443             && di->rodata_size > 0
    444             && *a >= di->rodata_debug_svma && *a < di->rodata_debug_svma + di->rodata_size) {
    445       *a += di->rodata_debug_bias;
    446    }
    447    else if (di->bss_present
    448             && di->bss_size > 0
    449             && *a >= di->bss_debug_svma && *a < di->bss_debug_svma + di->bss_size) {
    450       *a += di->bss_debug_bias;
    451    }
    452    else if (di->sbss_present
    453             && di->sbss_size > 0
    454             && *a >= di->sbss_debug_svma && *a < di->sbss_debug_svma + di->sbss_size) {
    455       *a += di->sbss_debug_bias;
    456    }
    457    else {
    458       return False;
    459    }
    460 
    461    return True;
    462 }
    463 
    464 
    465 /* Evaluate a standard DWARF3 expression.  See detailed description in
    466    priv_d3basics.h.  Doesn't handle DW_OP_piece/DW_OP_bit_piece yet.  */
    467 GXResult ML_(evaluate_Dwarf3_Expr) ( UChar* expr, UWord exprszB,
    468                                      GExpr* fbGX, RegSummary* regs,
    469                                      const DebugInfo* di,
    470                                      Bool push_initial_zero )
    471 {
    472 #  define N_EXPR_STACK 20
    473 
    474 #  define FAIL(_str)                                          \
    475       do {                                                    \
    476          res.kind = GXR_Failure;                              \
    477          res.word = (UWord)(_str);                            \
    478          return res;                                          \
    479       } while (0)
    480 
    481 #  define PUSH(_arg)                                          \
    482       do {                                                    \
    483          vg_assert(sp >= -1 && sp < N_EXPR_STACK);            \
    484          if (sp == N_EXPR_STACK-1)                            \
    485             FAIL("evaluate_Dwarf3_Expr: stack overflow(1)");  \
    486          sp++;                                                \
    487          stack[sp] = (_arg);                                  \
    488       } while (0)
    489 
    490 #  define POP(_lval)                                          \
    491       do {                                                    \
    492          vg_assert(sp >= -1 && sp < N_EXPR_STACK);            \
    493          if (sp == -1)                                        \
    494             FAIL("evaluate_Dwarf3_Expr: stack underflow(1)"); \
    495          _lval = stack[sp];                                   \
    496          sp--;                                                \
    497       } while (0)
    498 
    499    UChar    opcode;
    500    UChar*   limit;
    501    Int      sp; /* # of top element: valid is -1 .. N_EXPR_STACK-1 */
    502    Addr     stack[N_EXPR_STACK]; /* stack of addresses, as per D3 spec */
    503    GXResult fbval, res;
    504    Addr     a1;
    505    Word     sw1, sw2;
    506    UWord    uw1, uw2;
    507    Bool     ok;
    508 
    509    sp = -1;
    510    vg_assert(expr);
    511    vg_assert(exprszB >= 0);
    512    limit = expr + exprszB;
    513 
    514    /* Deal with the case where the entire expression is a single
    515       Register Name Operation (D3 spec sec 2.6.1).  Then the
    516       denotation of the expression as a whole is a register name. */
    517    if (exprszB == 1
    518        && expr[0] >= DW_OP_reg0 && expr[0] <= DW_OP_reg31) {
    519       res.kind = GXR_RegNo;
    520       res.word = (UWord)(expr[0] - DW_OP_reg0);
    521       return res;
    522    }
    523    if (exprszB > 1
    524        && expr[0] == DW_OP_regx) {
    525       /* JRS: 2008Feb20: I believe the following is correct, but would
    526          like to see a test case show up before enabling it. */
    527       expr++;
    528       res.kind = GXR_RegNo;
    529       res.word = (UWord)read_leb128U( &expr );
    530       if (expr != limit)
    531          FAIL("evaluate_Dwarf3_Expr: DW_OP_regx*: invalid expr size");
    532       else
    533          return res;
    534       /*NOTREACHED*/
    535    }
    536 
    537    /* Evidently this expression denotes a value, not a register name.
    538       So evaluate it accordingly. */
    539 
    540    if (push_initial_zero)
    541       PUSH(0);
    542 
    543    while (True) {
    544 
    545       vg_assert(sp >= -1 && sp < N_EXPR_STACK);
    546 
    547       if (expr > limit)
    548          /* overrun - something's wrong */
    549          FAIL("evaluate_Dwarf3_Expr: ran off end of expr");
    550 
    551       if (expr == limit) {
    552          /* end of expr - return expr on the top of stack. */
    553          if (sp == -1)
    554             /* stack empty.  Bad. */
    555             FAIL("evaluate_Dwarf3_Expr: stack empty at end of expr");
    556          else
    557             break;
    558       }
    559 
    560       opcode = *expr++;
    561       switch (opcode) {
    562          case DW_OP_addr:
    563             /* Presumably what is given in the Dwarf3 is a SVMA (how
    564                could it be otherwise?)  So we add the appropriate bias
    565                on before pushing the result. */
    566             a1 = ML_(read_Addr)(expr);
    567             if (bias_address(&a1, di)) {
    568                PUSH( a1 );
    569                expr += sizeof(Addr);
    570             }
    571             else {
    572                FAIL("evaluate_Dwarf3_Expr: DW_OP_addr with address "
    573                     "in unknown section");
    574             }
    575             break;
    576          case DW_OP_fbreg:
    577             if (!fbGX)
    578                FAIL("evaluate_Dwarf3_Expr: DW_OP_fbreg with "
    579                     "no expr for fbreg present");
    580             fbval = ML_(evaluate_GX)(fbGX, NULL, regs, di);
    581             /* Convert fbval into something we can use.  If we got a
    582                Value, no problem.  However, as per D3 spec sec 3.3.5
    583                (Low Level Information) sec 2, we could also get a
    584                RegNo, and that is taken to mean the value in the
    585                indicated register.  So we have to manually
    586                "dereference" it. */
    587             a1 = 0;
    588             switch (fbval.kind) {
    589                case GXR_Failure:
    590                   return fbval; /* propagate failure */
    591                case GXR_Addr:
    592                   a1 = fbval.word; break; /* use as-is */
    593                case GXR_RegNo:
    594                   ok = get_Dwarf_Reg( &a1, fbval.word, regs );
    595                   if (!ok) return fbval; /* propagate failure */
    596                   break;
    597                case GXR_Value:
    598                   FAIL("evaluate_Dwarf3_Expr: DW_OP_{implicit,stack}_value "
    599                        "in DW_AT_frame_base");
    600                default:
    601                   vg_assert(0);
    602             }
    603             sw1 = (Word)read_leb128S( &expr );
    604             PUSH( a1 + sw1 );
    605             break;
    606          /* DW_OP_breg* denotes 'contents of specified register, plus
    607             constant offset'.  So provided we know what the register's
    608             value is, we can evaluate this.  Contrast DW_OP_reg*,
    609             which indicates that denoted location is in a register
    610             itself.  If DW_OP_reg* shows up here the expression is
    611             malformed, since we are evaluating for value now, and
    612             DW_OP_reg* denotes a register location, not a value.  See
    613             D3 Spec sec 2.6.1 ("Register Name Operations") for
    614             details. */
    615          case DW_OP_breg0 ... DW_OP_breg31:
    616             if (!regs)
    617                FAIL("evaluate_Dwarf3_Expr: DW_OP_breg* but no reg info");
    618             a1 = 0;
    619             if (!get_Dwarf_Reg( &a1, opcode - DW_OP_breg0, regs ))
    620                FAIL("evaluate_Dwarf3_Expr: unhandled DW_OP_breg*");
    621             sw1 = (Word)read_leb128S( &expr );
    622             a1 += sw1;
    623             PUSH( a1 );
    624             break;
    625          case DW_OP_bregx:
    626             if (!regs)
    627                FAIL("evaluate_Dwarf3_Expr: DW_OP_bregx but no reg info");
    628             a1 = 0;
    629             uw1 = (UWord)read_leb128U( &expr );
    630             if (!get_Dwarf_Reg( &a1, uw1, regs ))
    631                FAIL("evaluate_Dwarf3_Expr: unhandled DW_OP_bregx reg value");
    632             sw1 = (Word)read_leb128S( &expr );
    633             a1 += sw1;
    634             PUSH( a1 );
    635             break;
    636          /* As per comment on DW_OP_breg*, the following denote that
    637             the value in question is in a register, not in memory.  So
    638             we simply return failure. (iow, the expression is
    639             malformed). */
    640          case DW_OP_reg0 ... DW_OP_reg31:
    641          case DW_OP_regx:
    642             FAIL("evaluate_Dwarf3_Expr: DW_OP_reg* "
    643                  "whilst evaluating for a value");
    644             break;
    645          case DW_OP_plus_uconst:
    646             POP(uw1);
    647             uw1 += (UWord)read_leb128U( &expr );
    648             PUSH(uw1);
    649             break;
    650          case DW_OP_GNU_push_tls_address:
    651             /* GDB contains the following cryptic comment: */
    652             /* Variable is at a constant offset in the thread-local
    653             storage block into the objfile for the current thread and
    654             the dynamic linker module containing this expression. Here
    655             we return returns the offset from that base.  The top of the
    656             stack has the offset from the beginning of the thread
    657             control block at which the variable is located.  Nothing
    658             should follow this operator, so the top of stack would be
    659             returned.  */
    660             /* But no spec resulting from Googling.  Punt for now. */
    661             FAIL("warning: evaluate_Dwarf3_Expr: unhandled "
    662                  "DW_OP_GNU_push_tls_address");
    663             /*NOTREACHED*/
    664          case DW_OP_deref:
    665             POP(uw1);
    666             if (VG_(am_is_valid_for_client)( (Addr)uw1, sizeof(Addr),
    667                                              VKI_PROT_READ )) {
    668                uw1 = ML_(read_UWord)((void *)uw1);
    669                PUSH(uw1);
    670             } else {
    671                FAIL("warning: evaluate_Dwarf3_Expr: DW_OP_deref: "
    672                     "address not valid for client");
    673             }
    674             break;
    675          case DW_OP_deref_size:
    676             POP(uw1);
    677             uw2 = *expr++;
    678             if (VG_(am_is_valid_for_client)( (Addr)uw1, uw2,
    679                                              VKI_PROT_READ )) {
    680                switch (uw2) {
    681                  case 1: uw1 = ML_(read_UChar)((void*)uw1); break;
    682                  case 2: uw1 = ML_(read_UShort)((void*)uw1); break;
    683                  case 4: uw1 = ML_(read_UInt)((void*)uw1); break;
    684                  case 8: uw1 = ML_(read_ULong)((void*)uw1); break;
    685                  default:
    686                     FAIL("warning: evaluate_Dwarf3_Expr: unhandled "
    687                          "DW_OP_deref_size size");
    688                }
    689                PUSH(uw1);
    690             } else {
    691                FAIL("warning: evaluate_Dwarf3_Expr: DW_OP_deref_size: "
    692                     "address not valid for client");
    693             }
    694             break;
    695          case DW_OP_lit0 ... DW_OP_lit31:
    696             PUSH(opcode - DW_OP_lit0);
    697             break;
    698          case DW_OP_const1u:
    699 	    uw1 = *expr++;
    700 	    PUSH(uw1);
    701             break;
    702          case DW_OP_const2u:
    703 	    uw1 = ML_(read_UShort)(expr);
    704 	    expr += 2;
    705 	    PUSH(uw1);
    706 	    break;
    707          case DW_OP_const4u:
    708 	    uw1 = ML_(read_UInt)(expr);
    709 	    expr += 4;
    710 	    PUSH(uw1);
    711 	    break;
    712          case DW_OP_const8u:
    713 	    uw1 = ML_(read_ULong)(expr);
    714 	    expr += 8;
    715 	    PUSH(uw1);
    716 	    break;
    717          case DW_OP_constu:
    718             uw1 = read_leb128U( &expr );
    719             PUSH(uw1);
    720             break;
    721          case DW_OP_const1s:
    722 	    uw1 = *(Char *)expr;
    723 	    expr++;
    724 	    PUSH(uw1);
    725             break;
    726          case DW_OP_const2s:
    727 	    uw1 = ML_(read_Short)(expr);
    728 	    expr += 2;
    729 	    PUSH(uw1);
    730 	    break;
    731          case DW_OP_const4s:
    732 	    uw1 = ML_(read_Int)(expr);
    733 	    expr += 4;
    734 	    PUSH(uw1);
    735 	    break;
    736          case DW_OP_const8s:
    737 	    uw1 = ML_(read_Long)(expr);
    738 	    expr += 8;
    739 	    PUSH(uw1);
    740 	    break;
    741          case DW_OP_consts:
    742             uw1 = read_leb128S( &expr );
    743             PUSH(uw1);
    744             break;
    745          case DW_OP_dup:
    746 	    POP(uw1);
    747 	    PUSH(uw1);
    748 	    PUSH(uw1);
    749 	    break;
    750 	 case DW_OP_drop:
    751 	    POP(uw1);
    752 	    break;
    753          case DW_OP_over:
    754             uw1 = 1;
    755             goto do_pick;
    756 	 case DW_OP_pick:
    757 	    uw1 = *expr++;
    758          do_pick:
    759             if (sp < (Int)uw1)
    760                FAIL("evaluate_Dwarf3_Expr: stack underflow");
    761             uw1 = stack[sp - uw1];
    762             PUSH(uw1);
    763             break;
    764          case DW_OP_swap:
    765             if (sp < 1)
    766                FAIL("evaluate_Dwarf3_Expr: stack underflow");
    767             uw1 = stack[sp];
    768             stack[sp] = stack[sp - 1];
    769             stack[sp - 1] = uw1;
    770             break;
    771          case DW_OP_rot:
    772             if (sp < 2)
    773                FAIL("evaluate_Dwarf3_Expr: stack underflow");
    774             uw1 = stack[sp];
    775             stack[sp] = stack[sp - 1];
    776             stack[sp - 1] = stack[sp - 2];
    777             stack[sp - 2] = uw1;
    778             break;
    779          case DW_OP_abs:
    780             POP(sw1);
    781             if (sw1 < 0)
    782                sw1 = -sw1;
    783             PUSH(sw1);
    784             break;
    785          case DW_OP_div:
    786             POP(sw2);
    787             if (sw2 == 0)
    788                FAIL("evaluate_Dwarf3_Expr: division by zero");
    789             POP(sw1);
    790             sw1 /= sw2;
    791             PUSH(sw1);
    792             break;
    793          case DW_OP_mod:
    794             POP(uw2);
    795             if (uw2 == 0)
    796                FAIL("evaluate_Dwarf3_Expr: division by zero");
    797             POP(uw1);
    798             uw1 %= uw2;
    799             PUSH(uw1);
    800             break;
    801 #define BINARY(name, op, s) \
    802          case DW_OP_##name:		\
    803             POP(s##w2);			\
    804             POP(s##w1);			\
    805             s##w1 = s##w1 op s##w2;	\
    806             PUSH(s##w1);		\
    807             break
    808 #define UNARY(name, op, s) \
    809          case DW_OP_##name:		\
    810             POP(s##w1);			\
    811             s##w1 = op s##w1;		\
    812             PUSH(s##w1);		\
    813             break
    814          BINARY (and, &, u);
    815          BINARY (minus, -, u);
    816          BINARY (mul, *, u);
    817          UNARY (neg, -, u);
    818          UNARY (not, ~, u);
    819          BINARY (or, |, u);
    820          BINARY (plus, +, u);
    821          BINARY (shl, <<, u);
    822          BINARY (shr, >>, u);
    823          BINARY (shra, >>, s);
    824          BINARY (xor, ^, u);
    825          BINARY (le, <=, s);
    826          BINARY (lt, <, s);
    827          BINARY (ge, >=, s);
    828          BINARY (gt, >, s);
    829          BINARY (ne, !=, u);
    830          BINARY (eq, ==, u);
    831 #undef UNARY
    832 #undef BINARY
    833          case DW_OP_skip:
    834             sw1 = ML_(read_Short)(expr);
    835             expr += 2;
    836             if (expr + sw1 < limit - exprszB)
    837                FAIL("evaluate_Dwarf3_Expr: DW_OP_skip before start of expr");
    838             if (expr + sw1 >= limit)
    839                FAIL("evaluate_Dwarf3_Expr: DW_OP_skip after end of expr");
    840             expr += sw1;
    841             break;
    842          case DW_OP_bra:
    843             sw1 = ML_(read_Short)(expr);
    844             expr += 2;
    845             if (expr + sw1 < limit - exprszB)
    846                FAIL("evaluate_Dwarf3_Expr: DW_OP_bra before start of expr");
    847             if (expr + sw1 >= limit)
    848                FAIL("evaluate_Dwarf3_Expr: DW_OP_bra after end of expr");
    849             POP(uw1);
    850             if (uw1)
    851                expr += sw1;
    852             break;
    853          case DW_OP_nop:
    854             break;
    855          case DW_OP_call_frame_cfa:
    856             if (!regs)
    857                FAIL("evaluate_Dwarf3_Expr: "
    858                     "DW_OP_call_frame_cfa but no reg info");
    859 #if defined(VGP_ppc32_linux) || defined(VGP_ppc64_linux)
    860             /* Valgrind on ppc32/ppc64 currently doesn't use unwind info. */
    861             uw1 = ML_(read_Addr)((UChar*)regs->sp);
    862 #else
    863             uw1 = ML_(get_CFA)(regs->ip, regs->sp, regs->fp, 0, ~(UWord) 0);
    864 #endif
    865             /* we expect this to fail on arm-linux, since ML_(get_CFA)
    866                always returns zero at present. */
    867             if (!uw1)
    868                FAIL("evaluate_Dwarf3_Expr: Could not resolve "
    869                     "DW_OP_call_frame_cfa");
    870             PUSH(uw1);
    871             break;
    872          case DW_OP_implicit_value:
    873             sw1 = (Word)read_leb128S( &expr );
    874             uw1 = 0;
    875             switch (sw1) {
    876                case 1:
    877                   uw1 = ML_(read_UChar)(expr);
    878                   expr += 1;
    879                   break;
    880                case 2:
    881                   uw1 = ML_(read_UShort)(expr);
    882                   expr += 2;
    883                   break;
    884                case 4:
    885                   uw1 = ML_(read_UInt)(expr);
    886                   expr += 4;
    887                   break;
    888                case 8:
    889                   uw1 = ML_(read_ULong)(expr);
    890                   expr += 8;
    891                   break;
    892                default:
    893                   FAIL("evaluate_Dwarf3_Expr: Unhandled "
    894                        "DW_OP_implicit_value size");
    895             }
    896             if (expr != limit)
    897                FAIL("evaluate_Dwarf3_Expr: DW_OP_implicit_value "
    898                     "does not terminate expression");
    899             res.word = uw1;
    900             res.kind = GXR_Value;
    901             return res;
    902          case DW_OP_stack_value:
    903             POP (uw1);
    904             res.word = uw1;
    905             res.kind = GXR_Value;
    906             if (expr != limit)
    907                FAIL("evaluate_Dwarf3_Expr: DW_OP_stack_value "
    908                     "does not terminate expression");
    909             break;
    910          default:
    911             if (!VG_(clo_xml))
    912                VG_(message)(Vg_DebugMsg,
    913                             "warning: evaluate_Dwarf3_Expr: unhandled "
    914                             "DW_OP_ 0x%x\n", (Int)opcode);
    915             FAIL("evaluate_Dwarf3_Expr: unhandled DW_OP_");
    916             /*NOTREACHED*/
    917       }
    918 
    919    }
    920 
    921    vg_assert(sp >= 0 && sp < N_EXPR_STACK);
    922    res.word = stack[sp];
    923    res.kind = GXR_Addr;
    924    return res;
    925 
    926 #  undef POP
    927 #  undef PUSH
    928 #  undef FAIL
    929 #  undef N_EXPR_STACK
    930 }
    931 
    932 
    933 /* Evaluate a so-called Guarded (DWARF3) expression.  See detailed
    934    description in priv_d3basics.h. */
    935 GXResult ML_(evaluate_GX)( GExpr* gx, GExpr* fbGX,
    936                            RegSummary* regs, const DebugInfo* di )
    937 {
    938    GXResult res;
    939    Addr     aMin, aMax;
    940    UChar    uc;
    941    UShort   nbytes;
    942    UWord    nGuards = 0;
    943    UChar* p = &gx->payload[0];
    944    uc = *p++; /*biasMe*/
    945    vg_assert(uc == 0 || uc == 1);
    946    /* in fact it's senseless to evaluate if the guards need biasing.
    947       So don't. */
    948    vg_assert(uc == 0);
    949    while (True) {
    950       uc = *p++;
    951       if (uc == 1) { /*isEnd*/
    952          /* didn't find any matching range. */
    953          res.kind = GXR_Failure;
    954          res.word = (UWord)"no matching range";
    955          return res;
    956       }
    957       vg_assert(uc == 0);
    958       aMin   = ML_(read_Addr)(p);   p += sizeof(Addr);
    959       aMax   = ML_(read_Addr)(p);   p += sizeof(Addr);
    960       nbytes = ML_(read_UShort)(p); p += sizeof(UShort);
    961       nGuards++;
    962       if (0) VG_(printf)("           guard %d: %#lx %#lx\n",
    963                          (Int)nGuards, aMin,aMax);
    964       if (regs == NULL) {
    965          vg_assert(aMin == (Addr)0);
    966          vg_assert(aMax == ~(Addr)0);
    967          /* Assert this is the first guard. */
    968          vg_assert(nGuards == 1);
    969          res = ML_(evaluate_Dwarf3_Expr)(
    970                   p, (UWord)nbytes, fbGX, regs, di,
    971                   False/*push_initial_zero*/ );
    972          /* Now check there are no more guards. */
    973          p += (UWord)nbytes;
    974          vg_assert(*p == 1); /*isEnd*/
    975          return res;
    976       } else {
    977          if (aMin <= regs->ip && regs->ip <= aMax) {
    978             /* found a matching range.  Evaluate the expression. */
    979             return ML_(evaluate_Dwarf3_Expr)(
    980                       p, (UWord)nbytes, fbGX, regs, di,
    981                       False/*push_initial_zero*/ );
    982          }
    983       }
    984       /* else keep searching */
    985       p += (UWord)nbytes;
    986    }
    987 }
    988 
    989 
    990 /* Evaluate a very simple Guarded (DWARF3) expression.  The expression
    991    is expected to denote a constant, with no reference to any
    992    registers nor to any frame base expression.  The expression is
    993    expected to have at least one guard.  If there is more than one
    994    guard, all the sub-expressions are evaluated and compared.  The
    995    address ranges on the guards are ignored.  GXR_Failure is returned
    996    in the following circumstances:
    997    * no guards
    998    * any of the subexpressions require a frame base expression
    999    * any of the subexpressions denote a register location
   1000    * any of the subexpressions do not produce a manifest constant
   1001    * there's more than one subexpression, all of which successfully
   1002      evaluate to a constant, but they don't all produce the same constant.
   1003    JRS 23Jan09: the special-casing in this function is a nasty kludge.
   1004    Really it ought to be pulled out and turned into a general
   1005    constant- expression evaluator.
   1006 */
   1007 GXResult ML_(evaluate_trivial_GX)( GExpr* gx, const DebugInfo* di )
   1008 {
   1009    GXResult   res;
   1010    Addr       aMin, aMax;
   1011    UChar      uc;
   1012    UShort     nbytes;
   1013    Word       i, nGuards;
   1014    MaybeULong *mul, *mul2;
   1015 
   1016    HChar*  badness = NULL;
   1017    UChar*  p       = &gx->payload[0]; /* must remain unsigned */
   1018    XArray* results = VG_(newXA)( ML_(dinfo_zalloc), "di.d3basics.etG.1",
   1019                                  ML_(dinfo_free),
   1020                                  sizeof(MaybeULong) );
   1021 
   1022    uc = *p++; /*biasMe*/
   1023    vg_assert(uc == 0 || uc == 1);
   1024    /* in fact it's senseless to evaluate if the guards need biasing.
   1025       So don't. */
   1026    vg_assert(uc == 0);
   1027 
   1028    nGuards = 0;
   1029    while (True) {
   1030       MaybeULong thisResult;
   1031       uc = *p++;
   1032       if (uc == 1) /*isEnd*/
   1033          break;
   1034       vg_assert(uc == 0);
   1035       aMin   = ML_(read_Addr)(p);   p += sizeof(Addr);
   1036       aMax   = ML_(read_Addr)(p);   p += sizeof(Addr);
   1037       nbytes = ML_(read_UShort)(p); p += sizeof(UShort);
   1038       nGuards++;
   1039       if (0) VG_(printf)("           guard %ld: %#lx %#lx\n",
   1040                          nGuards, aMin,aMax);
   1041 
   1042       thisResult.b  = False;
   1043       thisResult.ul = 0;
   1044 
   1045       /* Peer at this particular subexpression, to see if it's
   1046          obviously a constant. */
   1047       if (nbytes == 1 + sizeof(Addr) && *p == DW_OP_addr) {
   1048          /* DW_OP_addr a */
   1049          Addr a = ML_(read_Addr)((p+1));
   1050          if (bias_address(&a, di)) {
   1051             thisResult.b = True;
   1052             thisResult.ul = (ULong)a;
   1053          } else {
   1054             if (!badness)
   1055                badness = "trivial GExpr denotes constant address "
   1056                          "in unknown section (1)";
   1057          }
   1058       }
   1059       else
   1060       if (nbytes == 1 + sizeof(Addr) + 1 + 1
   1061           /* 11 byte block: 3 c0 b6 2b 0 0 0 0 0 23 4
   1062              (DW_OP_addr: 2bb6c0; DW_OP_plus_uconst: 4)
   1063              This is really a nasty kludge - only matches if the
   1064              trailing ULEB denotes a number in the range 0 .. 127
   1065              inclusive. */
   1066           && p[0] == DW_OP_addr
   1067           && p[1 + sizeof(Addr)] == DW_OP_plus_uconst
   1068           && p[1 + sizeof(Addr) + 1] < 0x80 /*1-byte ULEB*/) {
   1069          Addr a = ML_(read_Addr)(&p[1]);
   1070          if (bias_address(&a, di)) {
   1071             thisResult.b = True;
   1072             thisResult.ul = (ULong)a + (ULong)p[1 + sizeof(Addr) + 1];
   1073          } else {
   1074             if (!badness)
   1075                badness = "trivial GExpr denotes constant address "
   1076                          "in unknown section (2)";
   1077          }
   1078       }
   1079       else
   1080       if (nbytes == 2 + sizeof(Addr)
   1081           && *p == DW_OP_addr
   1082           && *(p + 1 + sizeof(Addr)) == DW_OP_GNU_push_tls_address) {
   1083          if (!badness)
   1084             badness = "trivial GExpr is DW_OP_addr plus trailing junk";
   1085       }
   1086       else if (nbytes >= 1 && *p >= DW_OP_reg0 && *p <= DW_OP_reg31) {
   1087          if (!badness)
   1088             badness = "trivial GExpr denotes register (1)";
   1089       }
   1090       else if (nbytes >= 1 && *p == DW_OP_fbreg) {
   1091          if (!badness)
   1092             badness = "trivial GExpr requires fbGX";
   1093       }
   1094       else if (nbytes >= 1 && *p >= DW_OP_breg0 && *p <= DW_OP_breg31) {
   1095          if (!badness)
   1096             badness = "trivial GExpr requires register value";
   1097       }
   1098       else if (nbytes >= 1 && *p == DW_OP_regx) {
   1099          if (!badness)
   1100             badness = "trivial GExpr denotes register (2)";
   1101       }
   1102       else if (0) {
   1103          VG_(printf)(" ML_(evaluate_trivial_GX): unhandled:\n   ");
   1104          ML_(pp_GX)( gx );
   1105          VG_(printf)("\n");
   1106          tl_assert(0);
   1107       }
   1108       else
   1109          if (!badness)
   1110             badness = "non-trivial GExpr";
   1111 
   1112       VG_(addToXA)( results, &thisResult );
   1113 
   1114       p += (UWord)nbytes;
   1115    }
   1116 
   1117    res.kind = GXR_Failure;
   1118 
   1119    tl_assert(nGuards == VG_(sizeXA)( results ));
   1120    tl_assert(nGuards >= 0);
   1121    if (nGuards == 0) {
   1122       tl_assert(!badness);
   1123       res.word = (UWord)"trivial GExpr has no guards (!)";
   1124       VG_(deleteXA)( results );
   1125       return res;
   1126    }
   1127 
   1128    for (i = 0; i < nGuards; i++) {
   1129       mul = VG_(indexXA)( results, i );
   1130       if (mul->b == False)
   1131          break;
   1132    }
   1133 
   1134    vg_assert(i >= 0 && i <= nGuards);
   1135    if (i < nGuards) {
   1136       /* at least one subexpression failed to produce a manifest constant. */
   1137       vg_assert(badness);
   1138       res.word = (UWord)badness;
   1139       VG_(deleteXA)( results );
   1140       return res;
   1141    }
   1142 
   1143    /* All the subexpressions produced a constant, but did they all produce
   1144       the same one? */
   1145    mul = VG_(indexXA)( results, 0 );
   1146    tl_assert(mul->b == True); /* we just established that all exprs are ok */
   1147 
   1148    for (i = 1; i < nGuards; i++) {
   1149       mul2 = VG_(indexXA)( results, i );
   1150       tl_assert(mul2->b == True);
   1151       if (mul2->ul != mul->ul) {
   1152          res.word = (UWord)"trivial GExpr: subexpressions disagree";
   1153          VG_(deleteXA)( results );
   1154          return res;
   1155       }
   1156    }
   1157 
   1158    /* Well, we have success.  All subexpressions evaluated, and
   1159       they all agree.  Hurrah. */
   1160    res.kind = GXR_Addr;
   1161    res.word = (UWord)mul->ul; /* NB: narrowing from ULong */
   1162    VG_(deleteXA)( results );
   1163    return res;
   1164 }
   1165 
   1166 
   1167 void ML_(pp_GXResult) ( GXResult res )
   1168 {
   1169    switch (res.kind) {
   1170       case GXR_Failure:
   1171          VG_(printf)("GXR_Failure(%s)", (HChar*)res.word); break;
   1172       case GXR_Addr:
   1173          VG_(printf)("GXR_Addr(0x%lx)", res.word); break;
   1174       case GXR_Value:
   1175          VG_(printf)("GXR_Value(0x%lx)", res.word); break;
   1176       case GXR_RegNo:
   1177          VG_(printf)("GXR_RegNo(%lu)", res.word); break;
   1178       default:
   1179          VG_(printf)("GXR_???"); break;
   1180    }
   1181 }
   1182 
   1183 
   1184 void ML_(pp_GX) ( GExpr* gx ) {
   1185    Addr   aMin, aMax;
   1186    UChar  uc;
   1187    UShort nbytes;
   1188    UChar* p = &gx->payload[0];
   1189    uc = *p++;
   1190    VG_(printf)("GX(%s){", uc == 0 ? "final" : "Breqd" );
   1191    vg_assert(uc == 0 || uc == 1);
   1192    while (True) {
   1193       uc = *p++;
   1194       if (uc == 1)
   1195          break; /*isEnd*/
   1196       vg_assert(uc == 0);
   1197       aMin   = ML_(read_Addr)(p);  p += sizeof(Addr);
   1198       aMax   = ML_(read_Addr)(p);  p += sizeof(Addr);
   1199       nbytes = ML_(read_UShort)(p); p += sizeof(UShort);
   1200       VG_(printf)("[%#lx,%#lx]=", aMin, aMax);
   1201       while (nbytes > 0) {
   1202          VG_(printf)("%02x", (UInt)*p++);
   1203          nbytes--;
   1204       }
   1205       if (*p == 0)
   1206          VG_(printf)(",");
   1207    }
   1208    VG_(printf)("}");
   1209 }
   1210 
   1211 
   1212 /*--------------------------------------------------------------------*/
   1213 /*--- end                                               d3basics.c ---*/
   1214 /*--------------------------------------------------------------------*/
   1215