Author: labath Date: Thu Dec 27 01:25:34 2018 New Revision: 350086 URL: http://llvm.org/viewvc/llvm-project?rev=350086&view=rev Log: DWARF: Fix a bug in array size computation
Summary: r346165 introduced a bug, where we would fail to parse the size of an array if that size happened to match an existing die offset. The logic was: if (DWARFDIE count = die.GetReferencedDie(DW_AT_count)) num_elements = compute_vla_size(count); else num_elements = die.GetUsigned(DW_AT_count); // a fixed-size array The problem with this logic was that GetReferencedDie did not take the form class of the attribute into account, and would happily return a die reference for any form, if its value happened to match some die. As this behavior is inconsistent with how llvm's DWARFFormValue class operates, I chose to fix the problem by making our version of this class match the llvm behavior. For this to work, I had to add an explicit form class check to the .apple_XXX tables parsing code, because they do (incorrectly?) use data forms as die references. Reviewers: aprantl, clayborg Subscribers: JDevlieghere, lldb-commits Differential Revision: https://reviews.llvm.org/D55991 Added: lldb/trunk/lit/SymbolFile/DWARF/array-sizes.s Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp lldb/trunk/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp Added: lldb/trunk/lit/SymbolFile/DWARF/array-sizes.s URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/lit/SymbolFile/DWARF/array-sizes.s?rev=350086&view=auto ============================================================================== --- lldb/trunk/lit/SymbolFile/DWARF/array-sizes.s (added) +++ lldb/trunk/lit/SymbolFile/DWARF/array-sizes.s Thu Dec 27 01:25:34 2018 @@ -0,0 +1,147 @@ +# This tests a bug where we would incorrectly parse the size of an array if that +# size happened to match an existing DIE offset. This happened because we +# misinterpreted that value as a reference to a DIE specifying the VLA size even +# though the form was a data form (as it should be). + +# REQUIRES: lld + +# RUN: llvm-mc -triple x86_64-pc-linux %s -filetype=obj > %t.o +# RUN: ld.lld %t.o -o %t +# RUN: lldb-test symbols %t | FileCheck %s + +# CHECK: Variable{0xffffffff0000001e}, name = "X" +# CHECK-SAME: type = {ffffffff00000033} 0x{{[0-9a-f]*}} (char [56]) + + +# Generated from "char X[47];" +# The array size was modified by hand. + + .text + .file "-" + .file 1 "/tmp" "<stdin>" + .type X,@object # @X + .comm X,63,16 + .section .debug_str,"MS",@progbits,1 +.Linfo_string0: + .asciz "clang version 8.0.0 (trunk 349604) (llvm/trunk 349608)" # string offset=0 +.Linfo_string1: + .asciz "-" # string offset=55 +.Linfo_string2: + .asciz "/tmp" # string offset=57 +.Linfo_string3: + .asciz "X" # string offset=62 +.Linfo_string4: + .asciz "char" # string offset=64 +.Linfo_string5: + .asciz "__ARRAY_SIZE_TYPE__" # string offset=69 + .section .debug_abbrev,"",@progbits + .byte 1 # Abbreviation Code + .byte 17 # DW_TAG_compile_unit + .byte 1 # DW_CHILDREN_yes + .byte 37 # DW_AT_producer + .byte 14 # DW_FORM_strp + .byte 19 # DW_AT_language + .byte 5 # DW_FORM_data2 + .byte 3 # DW_AT_name + .byte 14 # DW_FORM_strp + .byte 16 # DW_AT_stmt_list + .byte 23 # DW_FORM_sec_offset + .byte 27 # DW_AT_comp_dir + .byte 14 # DW_FORM_strp + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 2 # Abbreviation Code + .byte 52 # DW_TAG_variable + .byte 0 # DW_CHILDREN_no + .byte 3 # DW_AT_name + .byte 14 # DW_FORM_strp + .byte 73 # DW_AT_type + .byte 19 # DW_FORM_ref4 + .byte 63 # DW_AT_external + .byte 25 # DW_FORM_flag_present + .byte 58 # DW_AT_decl_file + .byte 11 # DW_FORM_data1 + .byte 59 # DW_AT_decl_line + .byte 11 # DW_FORM_data1 + .byte 2 # DW_AT_location + .byte 24 # DW_FORM_exprloc + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 3 # Abbreviation Code + .byte 1 # DW_TAG_array_type + .byte 1 # DW_CHILDREN_yes + .byte 73 # DW_AT_type + .byte 19 # DW_FORM_ref4 + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 4 # Abbreviation Code + .byte 33 # DW_TAG_subrange_type + .byte 0 # DW_CHILDREN_no + .byte 73 # DW_AT_type + .byte 19 # DW_FORM_ref4 + .byte 55 # DW_AT_count + .byte 11 # DW_FORM_data1 + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 5 # Abbreviation Code + .byte 36 # DW_TAG_base_type + .byte 0 # DW_CHILDREN_no + .byte 3 # DW_AT_name + .byte 14 # DW_FORM_strp + .byte 62 # DW_AT_encoding + .byte 11 # DW_FORM_data1 + .byte 11 # DW_AT_byte_size + .byte 11 # DW_FORM_data1 + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 6 # Abbreviation Code + .byte 36 # DW_TAG_base_type + .byte 0 # DW_CHILDREN_no + .byte 3 # DW_AT_name + .byte 14 # DW_FORM_strp + .byte 11 # DW_AT_byte_size + .byte 11 # DW_FORM_data1 + .byte 62 # DW_AT_encoding + .byte 11 # DW_FORM_data1 + .byte 0 # EOM(1) + .byte 0 # EOM(2) + .byte 0 # EOM(3) + .section .debug_info,"",@progbits +.Lcu_begin0: + .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit +.Ldebug_info_start0: + .short 4 # DWARF version number + .long .debug_abbrev # Offset Into Abbrev. Section + .byte 8 # Address Size (in bytes) + .byte 1 # Abbrev [1] 0xb:0x43 DW_TAG_compile_unit + .long .Linfo_string0 # DW_AT_producer + .short 12 # DW_AT_language + .long .Linfo_string1 # DW_AT_name + .long 0 # DW_AT_stmt_list + .long .Linfo_string2 # DW_AT_comp_dir + .byte 2 # Abbrev [2] 0x1e:0x15 DW_TAG_variable + .long .Linfo_string3 # DW_AT_name + .long 51 # DW_AT_type + # DW_AT_external + .byte 1 # DW_AT_decl_file + .byte 1 # DW_AT_decl_line + .byte 9 # DW_AT_location + .byte 3 + .quad X + .byte 3 # Abbrev [3] 0x33:0xc DW_TAG_array_type + .long 63 # DW_AT_type +.Ldie: + .byte 4 # Abbrev [4] 0x38:0x6 DW_TAG_subrange_type + .long 70 # DW_AT_type + .byte .Ldie-.Lcu_begin0 # DW_AT_count - should match the offset of an existing die + .byte 0 # End Of Children Mark + .byte 5 # Abbrev [5] 0x3f:0x7 DW_TAG_base_type + .long .Linfo_string4 # DW_AT_name + .byte 6 # DW_AT_encoding + .byte 1 # DW_AT_byte_size + .byte 6 # Abbrev [6] 0x46:0x7 DW_TAG_base_type + .long .Linfo_string5 # DW_AT_name + .byte 8 # DW_AT_byte_size + .byte 7 # DW_AT_encoding + .byte 0 # End Of Children Mark +.Ldebug_info_end0: Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp?rev=350086&r1=350085&r2=350086&view=diff ============================================================================== --- lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp (original) +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp Thu Dec 27 01:25:34 2018 @@ -604,7 +604,7 @@ dw_addr_t DWARFFormValue::Address() cons } uint64_t DWARFFormValue::Reference() const { - uint64_t die_offset = m_value.value.uval; + uint64_t value = m_value.value.uval; switch (m_form) { case DW_FORM_ref1: case DW_FORM_ref2: @@ -613,32 +613,36 @@ uint64_t DWARFFormValue::Reference() con case DW_FORM_ref_udata: assert(m_cu); // CU must be valid for DW_FORM_ref forms that are compile // unit relative or we will get this wrong - die_offset += m_cu->GetOffset(); - break; + return value + m_cu->GetOffset(); + + case DW_FORM_ref_addr: + case DW_FORM_ref_sig8: + case DW_FORM_GNU_ref_alt: + return value; default: - break; + return DW_INVALID_OFFSET; } - - return die_offset; } uint64_t DWARFFormValue::Reference(dw_offset_t base_offset) const { - uint64_t die_offset = m_value.value.uval; + uint64_t value = m_value.value.uval; switch (m_form) { case DW_FORM_ref1: case DW_FORM_ref2: case DW_FORM_ref4: case DW_FORM_ref8: case DW_FORM_ref_udata: - die_offset += base_offset; - break; + return value + base_offset; + + case DW_FORM_ref_addr: + case DW_FORM_ref_sig8: + case DW_FORM_GNU_ref_alt: + return value; default: - break; + return DW_INVALID_OFFSET; } - - return die_offset; } const uint8_t *DWARFFormValue::BlockData() const { return m_value.data; } Modified: lldb/trunk/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp?rev=350086&r1=350085&r2=350086&view=diff ============================================================================== --- lldb/trunk/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp (original) +++ lldb/trunk/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp Thu Dec 27 01:25:34 2018 @@ -279,7 +279,9 @@ bool DWARFMappedHash::Header::Read(const switch (header_data.atoms[i].type) { case eAtomTypeDIEOffset: // DIE offset, check form for encoding hash_data.offset = - (dw_offset_t)form_value.Reference(header_data.die_base_offset); + DWARFFormValue::IsDataForm(form_value.Form()) + ? form_value.Unsigned() + : form_value.Reference(header_data.die_base_offset); break; case eAtomTypeTag: // DW_TAG value for the DIE _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
