96601ec28b
Summary: This patch fixes a crash encountered when debugging optimized code. If some variable has been completely optimized out, but it's value is nonetheless known, the compiler can replace it with a DWARF expression computing its value. The evaluating these expressions results in a eValueTypeHostAddress Value object, as it's contents are computed into an lldb buffer. However, any value that is obtained by dereferencing pointers in this object should no longer have the "host" address type. Lldb had code to account for this, but it was only present in the ValueObjectVariable class. This wasn't enough when the object being described was a struct, as then the object holding the actual pointer was a ValueObjectChild. This caused lldb to dereference the contained pointer in the context of the host process and crash. Though I am not an expert on ValueObjects, it seems to me that this children address type logic should apply to all types of objects (and indeed, applying applying the same logic to ValueObjectChild fixes the crash). Therefore, I move this code to the base class, and arrange it to be run everytime the value is updated. The test case is a reduced and simplified version of the original debug info triggering the crash. Originally we were dealing with a local variable, but as these require a running process to display, I changed it to use a global one instead. Reviewers: jingham, clayborg Subscribers: aprantl, lldb-commits Differential Revision: https://reviews.llvm.org/D69273
114 lines
5.6 KiB
ArmAsm
114 lines
5.6 KiB
ArmAsm
# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-pc-linux %s
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# RUN: %lldb %t -o "target variable reset" -b | FileCheck %s
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# CHECK: (lldb) target variable reset
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# CHECK: (auto_reset) reset = {
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# CHECK: ptr = 0xdeadbeefbaadf00d
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# CHECK: prev = false
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# CHECK: }
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.section .debug_abbrev,"",@progbits
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.byte 1 # Abbreviation Code
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.byte 17 # DW_TAG_compile_unit
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.byte 1 # DW_CHILDREN_yes
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 2 # Abbreviation Code
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.byte 52 # DW_TAG_variable
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.byte 0 # DW_CHILDREN_no
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.byte 3 # DW_AT_name
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.byte 8 # DW_FORM_string
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.byte 73 # DW_AT_type
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.byte 19 # DW_FORM_ref4
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.byte 2 # DW_AT_location
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.byte 24 # DW_FORM_exprloc
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 3 # Abbreviation Code
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.byte 36 # DW_TAG_base_type
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.byte 0 # DW_CHILDREN_no
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.byte 3 # DW_AT_name
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.byte 8 # DW_FORM_string
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.byte 62 # DW_AT_encoding
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.byte 11 # DW_FORM_data1
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.byte 11 # DW_AT_byte_size
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.byte 11 # DW_FORM_data1
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 4 # Abbreviation Code
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.byte 19 # DW_TAG_structure_type
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.byte 1 # DW_CHILDREN_yes
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.byte 3 # DW_AT_name
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.byte 8 # DW_FORM_string
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.byte 11 # DW_AT_byte_size
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.byte 11 # DW_FORM_data1
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 5 # Abbreviation Code
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.byte 13 # DW_TAG_member
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.byte 0 # DW_CHILDREN_no
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.byte 3 # DW_AT_name
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.byte 8 # DW_FORM_string
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.byte 73 # DW_AT_type
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.byte 19 # DW_FORM_ref4
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.byte 56 # DW_AT_data_member_location
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.byte 11 # DW_FORM_data1
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 6 # Abbreviation Code
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.byte 15 # DW_TAG_pointer_type
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.byte 0 # DW_CHILDREN_no
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.byte 73 # DW_AT_type
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.byte 19 # DW_FORM_ref4
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.byte 0 # EOM(1)
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.byte 0 # EOM(2)
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.byte 0 # EOM(3)
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.section .debug_info,"",@progbits
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.Lcu_begin0:
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.long .Lcu_end-.Lcu_start # Length of Unit
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.Lcu_start:
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.short 4 # DWARF version number
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.long .debug_abbrev # Offset Into Abbrev. Section
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.byte 8 # Address Size (in bytes)
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.byte 1 # Abbrev [1] 0xb:0x6c DW_TAG_compile_unit
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.Lbool:
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.byte 3 # Abbrev [3] 0x33:0x7 DW_TAG_base_type
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.asciz "bool" # DW_AT_name
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.byte 2 # DW_AT_encoding
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.byte 1 # DW_AT_byte_size
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.byte 2 # Abbrev [2] 0x3a:0x15 DW_TAG_variable
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.asciz "reset" # DW_AT_name
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.long .Lstruct # DW_AT_type
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.byte 2f-1f # DW_AT_location
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1:
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.byte 0xe # DW_OP_constu
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.quad 0xdeadbeefbaadf00d
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.byte 0x9f # DW_OP_stack_value
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.byte 0x93 # DW_OP_piece
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.uleb128 8
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.byte 0xe # DW_OP_constu
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.quad 0
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.byte 0x9f # DW_OP_stack_value
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.byte 0x93 # DW_OP_piece
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.uleb128 8
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2:
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.Lstruct:
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.byte 4 # Abbrev [4] 0x4f:0x22 DW_TAG_structure_type
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.asciz "auto_reset" # DW_AT_name
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.byte 16 # DW_AT_byte_size
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.byte 5 # Abbrev [5] 0x58:0xc DW_TAG_member
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.asciz "ptr" # DW_AT_name
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.long .Lbool_ptr # DW_AT_type
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.byte 0 # DW_AT_data_member_location
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.byte 5 # Abbrev [5] 0x64:0xc DW_TAG_member
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.asciz "prev" # DW_AT_name
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.long .Lbool # DW_AT_type
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.byte 8 # DW_AT_data_member_location
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.byte 0 # End Of Children Mark
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.Lbool_ptr:
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.byte 6 # Abbrev [6] 0x71:0x5 DW_TAG_pointer_type
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.long .Lbool # DW_AT_type
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.byte 0 # End Of Children Mark
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.Lcu_end:
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