[lldb] Skip declaration DIEs in the debug_names index #94744
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This makes sure we try to process declaration DIEs that are erroneously present in the index. Until bd5c636, clang was emitting index entries for declaration DIEs with DW_AT_signature attributes. This makes sure to avoid returning those DIEs as the definitions of a type, but also makes sure to pass through DIEs referring to static constexpr member variables, which is a (probably nonconforming) extension used by dsymutil. It adds test cases for both of the scenarios. It is essentially a recommit of llvm#91808.
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@llvm/pr-subscribers-lldb Author: Pavel Labath (labath) ChangesThis makes sure we try to process declaration DIEs that are erroneously present in the index. Until bd5c636, clang was emitting index entries for declaration DIEs with DW_AT_signature attributes. This makes sure to avoid returning those DIEs as the definitions of a type, but also makes sure to pass through DIEs referring to static constexpr member variables, which is a (probably nonconforming) extension used by dsymutil. It adds test cases for both of the scenarios. It is essentially a recommit of #91808. Patch is 26.03 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/94744.diff 3 Files Affected:
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp
index 90e42be7202d8..1d17f20670eed 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp
@@ -85,6 +85,11 @@ bool DebugNamesDWARFIndex::ProcessEntry(
DWARFDIE die = GetDIE(entry);
if (!die)
return true;
+ // Clang used to erroneously emit index entries for declaration DIEs in case
+ // when the definition is in a type unit (llvm.org/pr77696).
+ if (die.IsStructUnionOrClass() &&
+ die.GetAttributeValueAsUnsigned(DW_AT_declaration, 0))
+ return true;
return callback(die);
}
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-signature.s b/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-signature.s
new file mode 100644
index 0000000000000..7b845a72bbed4
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-signature.s
@@ -0,0 +1,265 @@
+## Test that we can correctly complete types even if the debug_names index
+## contains entries referring to declaration dies (clang emitted entries like
+## that until bd5c6367bd7).
+##
+## This test consists of two compile units and one type unit. CU1 has the
+## definition of a variable, but only a forward-declaration of its type. When
+## attempting to find a definition, the debug_names lookup will return the DIE
+## in CU0, which is also a forward-declaration (with a reference to a type
+## unit). LLDB needs to find the definition of the type within the type unit.
+
+# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t
+# RUN: %lldb %t -o "target variable s" -o exit | FileCheck %s
+
+# CHECK: (lldb) target variable s
+# CHECK-NEXT: (Struct) s = (member = 47)
+
+ .data
+ .p2align 2, 0x0
+ .long 0
+s:
+ .long 47 # 0x2f
+
+ .section .debug_abbrev,"",@progbits
+ .byte 1 # Abbreviation Code
+ .byte 65 # DW_TAG_type_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 2 # Abbreviation Code
+ .byte 19 # DW_TAG_structure_type
+ .byte 1 # DW_CHILDREN_yes
+ .byte 54 # DW_AT_calling_convention
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 13 # DW_TAG_member
+ .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 56 # DW_AT_data_member_location
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # 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 5 # Abbreviation Code
+ .byte 17 # DW_TAG_compile_unit
+ .byte 1 # DW_CHILDREN_yes
+ .byte 37 # DW_AT_producer
+ .byte 8 # DW_FORM_string
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 6 # 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 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 7 # Abbreviation Code
+ .byte 19 # DW_TAG_structure_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 60 # DW_AT_declaration
+ .byte 25 # DW_FORM_flag_present
+ .byte 105 # DW_AT_signature
+ .byte 32 # DW_FORM_ref_sig8
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 8 # Abbreviation Code
+ .byte 19 # DW_TAG_structure_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 60 # DW_AT_declaration
+ .byte 25 # DW_FORM_flag_present
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 0 # EOM(3)
+
+ .section .debug_info,"",@progbits
+.Ltu_begin0:
+ .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit
+.Ldebug_info_start0:
+ .short 5 # DWARF version number
+ .byte 2 # DWARF Unit Type
+ .byte 8 # Address Size (in bytes)
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .quad 4878254330033667422 # Type Signature
+ .long .LStruct_def-.Ltu_begin0 # Type DIE Offset
+ .byte 1 # Abbrev [1] 0x18:0x20 DW_TAG_type_unit
+ .short 33 # DW_AT_language
+.LStruct_def:
+ .byte 2 # Abbrev [2] 0x23:0x10 DW_TAG_structure_type
+ .byte 5 # DW_AT_calling_convention
+ .long .Linfo_string6 # DW_AT_name
+ .byte 4 # DW_AT_byte_size
+ .byte 3 # Abbrev [3] 0x29:0x9 DW_TAG_member
+ .long .Linfo_string4 # DW_AT_name
+ .long .Lint-.Ltu_begin0 # DW_AT_type
+ .byte 0 # DW_AT_data_member_location
+ .byte 0 # End Of Children Mark
+.Lint:
+ .byte 4 # Abbrev [4] 0x33:0x4 DW_TAG_base_type
+ .long .Linfo_string5 # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end0:
+
+.Lcu_begin0:
+ .long .Ldebug_info_end1-.Ldebug_info_start1 # Length of Unit
+.Ldebug_info_start1:
+ .short 5 # DWARF version number
+ .byte 1 # DWARF Unit Type
+ .byte 8 # Address Size (in bytes)
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 5 # Abbrev [5] 0xc:0x27 DW_TAG_compile_unit
+ .asciz "Hand-written DWARF" # DW_AT_producer
+ .short 33 # DW_AT_language
+.Ls:
+ .byte 6 # Abbrev [6] 0x1e:0xb DW_TAG_variable
+ .long .Linfo_string3 # DW_AT_name
+ .long .LStruct_decl2-.Lcu_begin0 # DW_AT_type
+ .byte 9 # DW_AT_location
+ .byte 3
+ .quad s
+.LStruct_decl2:
+ .byte 8 # Abbrev [8] 0x29:0x9 DW_TAG_structure_type
+ .long .Linfo_string6 # DW_AT_name
+ # DW_AT_declaration
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end1:
+
+.Lcu_begin1:
+ .long .Ldebug_info_end2-.Ldebug_info_start2 # Length of Unit
+.Ldebug_info_start2:
+ .short 5 # DWARF version number
+ .byte 1 # DWARF Unit Type
+ .byte 8 # Address Size (in bytes)
+ .long .debug_abbrev # Offset Into Abbrev. Section
+ .byte 5 # Abbrev [5] 0xc:0x27 DW_TAG_compile_unit
+ .asciz "Hand-written DWARF" # DW_AT_producer
+ .short 33 # DW_AT_language
+.LStruct_decl:
+ .byte 7 # Abbrev [7] 0x29:0x9 DW_TAG_structure_type
+ # DW_AT_declaration
+ .quad 4878254330033667422 # DW_AT_signature
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end2:
+
+ .section .debug_str,"MS",@progbits,1
+.Linfo_string3:
+ .asciz "s" # string offset=60
+.Linfo_string4:
+ .asciz "member" # string offset=62
+.Linfo_string5:
+ .asciz "int" # string offset=69
+.Linfo_string6:
+ .asciz "Struct" # string offset=73
+
+ .section .debug_names,"",@progbits
+ .long .Lnames_end0-.Lnames_start0 # Header: unit length
+.Lnames_start0:
+ .short 5 # Header: version
+ .short 0 # Header: padding
+ .long 2 # Header: compilation unit count
+ .long 1 # Header: local type unit count
+ .long 0 # Header: foreign type unit count
+ .long 0 # Header: bucket count
+ .long 3 # Header: name count
+ .long .Lnames_abbrev_end0-.Lnames_abbrev_start0 # Header: abbreviation table size
+ .long 8 # Header: augmentation string size
+ .ascii "LLVM0700" # Header: augmentation string
+ .long .Lcu_begin0 # Compilation unit 0
+ .long .Lcu_begin1 # Compilation unit 1
+ .long .Ltu_begin0 # Type unit 0
+ .long .Linfo_string6 # String in Bucket 0: Struct
+ .long .Linfo_string3 # String in Bucket 1: s
+ .long .Linfo_string5 # String in Bucket 2: int
+ .long .Lnames1-.Lnames_entries0 # Offset in Bucket 0
+ .long .Lnames2-.Lnames_entries0 # Offset in Bucket 1
+ .long .Lnames0-.Lnames_entries0 # Offset in Bucket 2
+.Lnames_abbrev_start0:
+ .byte 1 # Abbrev code
+ .byte 19 # DW_TAG_structure_type
+ .byte 2 # DW_IDX_type_unit
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_IDX_die_offset
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # End of abbrev
+ .byte 0 # End of abbrev
+ .byte 2 # Abbrev code
+ .byte 52 # DW_TAG_variable
+ .byte 1 # DW_IDX_compile_unit
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_IDX_die_offset
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # End of abbrev
+ .byte 0 # End of abbrev
+ .byte 3 # Abbrev code
+ .byte 36 # DW_TAG_base_type
+ .byte 2 # DW_IDX_type_unit
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_IDX_die_offset
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # End of abbrev
+ .byte 0 # End of abbrev
+ .byte 4 # Abbrev code
+ .byte 19 # DW_TAG_structure_type
+ .byte 1 # DW_IDX_compile_unit
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_IDX_die_offset
+ .byte 19 # DW_FORM_ref4
+ .byte 0 # End of abbrev
+ .byte 0 # End of abbrev
+ .byte 0 # End of abbrev list
+.Lnames_abbrev_end0:
+.Lnames_entries0:
+.Lnames1:
+ .byte 4 # Abbreviation code
+ .byte 1 # DW_IDX_compile_unit
+ .long .LStruct_decl-.Lcu_begin1 # DW_IDX_die_offset
+ .byte 1 # Abbreviation code
+ .byte 0 # DW_IDX_type_unit
+ .long .LStruct_def-.Ltu_begin0 # DW_IDX_die_offset
+ .byte 0
+ # End of list: Struct
+.Lnames2:
+ .byte 2 # Abbreviation code
+ .byte 0 # DW_IDX_compile_unit
+ .long .Ls-.Lcu_begin0 # DW_IDX_die_offset
+ .byte 0
+ # End of list: s
+.Lnames0:
+ .byte 3 # Abbreviation code
+ .byte 0 # DW_IDX_type_unit
+ .long .Lint-.Ltu_begin0 # DW_IDX_die_offset
+ .byte 0
+ # End of list: int
+ .p2align 2, 0x0
+.Lnames_end0:
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-static-constexpr-member.s b/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-static-constexpr-member.s
new file mode 100644
index 0000000000000..9cb534207c3d1
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/x86/debug-names-static-constexpr-member.s
@@ -0,0 +1,169 @@
+## Check that lldb can locate a static constant variable when its declaration is
+## referenced by a debug_names index. This is a non-conforming extension used by
+## dsymutil.
+
+# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t
+# RUN: %lldb %t -o "target variable Class::constant" \
+# RUN: -o "expr -l c++ -- Class::constant" -o exit | FileCheck %s
+
+# CHECK: (lldb) target variable Class::constant
+# CHECK-NEXT: (const int) Class::constant = 47
+# CHECK: (lldb) expr -l c++ -- Class::constant
+# CHECK-NEXT: (const int) $0 = 47
+
+ .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 8 # DW_FORM_string
+ .byte 19 # DW_AT_language
+ .byte 5 # DW_FORM_data2
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 2 # DW_TAG_class_type
+ .byte 1 # DW_CHILDREN_yes
+ .byte 54 # DW_AT_calling_convention
+ .byte 11 # DW_FORM_data1
+ .byte 3 # DW_AT_name
+ .byte 14 # DW_FORM_strp
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # 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 60 # DW_AT_declaration
+ .byte 25 # DW_FORM_flag_present
+ .byte 28 # DW_AT_const_value
+ .byte 13 # DW_FORM_sdata
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 5 # Abbreviation Code
+ .byte 38 # DW_TAG_const_type
+ .byte 0 # DW_CHILDREN_no
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .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
+ ...
[truncated]
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I should add that I'm pretty sure the index entries pointing to signature declaration DIEs were not the cause of crashes in @ZequanWu's PR, after creating the test case (what I think is the worst possible situation) and stepping through the code, I realized that these DIEs would get filtered out anyway on line DWARFIndex.cpp:126 (because |
Michael137
approved these changes
Jun 7, 2024
Closed
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This makes sure we try to process declaration DIEs that are erroneously present in the index. Until bd5c636, clang was emitting index entries for declaration DIEs with DW_AT_signature attributes. This makes sure to avoid returning those DIEs as the definitions of a type, but also makes sure to pass through DIEs referring to static constexpr member variables, which is a (probably nonconforming) extension used by dsymutil.
It adds test cases for both of the scenarios. It is essentially a recommit of #91808.