[Lldb-commits] [lldb] 25bbceb - [LLDB] Fix how ValueObjectChild handles bit-fields stored in a Scalar in UpdateValue()
via lldb-commits
lldb-commits at lists.llvm.org
Thu Aug 13 11:53:23 PDT 2020
Author: shafik
Date: 2020-08-13T11:53:14-07:00
New Revision: 25bbceb047a3ce85394d510a16bd3fcfd69b8c75
URL: https://github.com/llvm/llvm-project/commit/25bbceb047a3ce85394d510a16bd3fcfd69b8c75
DIFF: https://github.com/llvm/llvm-project/commit/25bbceb047a3ce85394d510a16bd3fcfd69b8c75.diff
LOG: [LLDB] Fix how ValueObjectChild handles bit-fields stored in a Scalar in UpdateValue()
When bit-field data was stored in a Scalar in ValueObjectChild during UpdateValue()
it was extracting the bit-field value. Later on in lldb_private::DumpDataExtractor(…)
we were again attempting to extract the bit-field. Which would then not obtain the
correct value. This will remove the extra extraction in UpdateValue().
We hit this specific case when values are passed in registers, which we could only
reproduce in an optimized build.
Differential Revision: https://reviews.llvm.org/D85376
Added:
lldb/test/Shell/SymbolFile/DWARF/DW_AT_data_bit_offset-DW_OP_stack_value.s
Modified:
lldb/source/Core/ValueObjectChild.cpp
Removed:
################################################################################
diff --git a/lldb/source/Core/ValueObjectChild.cpp b/lldb/source/Core/ValueObjectChild.cpp
index 28cb49328f34..1059c8f34b3b 100644
--- a/lldb/source/Core/ValueObjectChild.cpp
+++ b/lldb/source/Core/ValueObjectChild.cpp
@@ -199,11 +199,7 @@ bool ValueObjectChild::UpdateValue() {
// try to extract the child value from the parent's scalar value
{
Scalar scalar(m_value.GetScalar());
- if (m_bitfield_bit_size)
- scalar.ExtractBitfield(m_bitfield_bit_size,
- m_bitfield_bit_offset);
- else
- scalar.ExtractBitfield(8 * m_byte_size, 8 * m_byte_offset);
+ scalar.ExtractBitfield(8 * m_byte_size, 8 * m_byte_offset);
m_value.GetScalar() = scalar;
}
break;
diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_data_bit_offset-DW_OP_stack_value.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_data_bit_offset-DW_OP_stack_value.s
new file mode 100644
index 000000000000..074da09bc61e
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_data_bit_offset-DW_OP_stack_value.s
@@ -0,0 +1,312 @@
+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-apple-macosx10.15.0 %s
+# RUN: %lldb %t -o "target variable ug" -b | FileCheck %s
+
+# CHECK: (lldb) target variable ug
+# CHECK: (U) ug = {
+# CHECK: raw = 1688469761
+# CHECK: = (a = 1, b = 1, c = 36, d = 2, e = 36, f = 1)
+# CHECK: }
+
+# We are testing how ValueObject deals with bit-fields when an argument is
+# passed by register. Compiling at -O1 allows us to capture this case and
+# test it.
+#
+# typedef union {
+# unsigned raw;
+# struct {
+# unsigned a : 8;
+# unsigned b : 8;
+# unsigned c : 6;
+# unsigned d : 2;
+# unsigned e : 6;
+# unsigned f : 2;
+# };
+# } U;
+#
+# // This appears first in the debug info and pulls the type definition in...
+# static U __attribute__((used)) _type_anchor;
+# // ... then our useful variable appears last in the debug info and we can
+# // tweak the assembly without needing to edit a lot of offsets by hand.
+# static U ug;
+#
+# extern void f(U);
+#
+# // Omit debug info for main.
+# __attribute__((nodebug))
+# int main() {
+# ug.raw = 0x64A40101;
+# f(ug);
+# f((U)ug.raw);
+# }
+#
+# Compiled as follows:
+#
+# clang -O1 -gdwarf-4 weird.c -S -o weird.s
+#
+# Then the DWARF was hand modified to get DW_AT_LOCATION for ug from:
+#
+# DW_AT_location (DW_OP_addr 0x3f8, DW_OP_deref, DW_OP_constu 0x64a40101, DW_OP_mul, DW_OP_lit0, DW_OP_plus, DW_OP_stack_value)
+#
+# to this:
+#
+# DW_AT_location (DW_OP_constu 0x64a40101, DW_OP_stack_value)
+#
+# to work-around a seperate bug.
+
+.zerofill __DATA,__bss,__type_anchor,4,2 ## @_type_anchor
+.zerofill __DATA,__bss,_ug.0,1,2 ## @ug.0
+ .no_dead_strip __type_anchor
+ .section __DWARF,__debug_str,regular,debug
+Linfo_string:
+ .zero 138
+ .asciz "_type_anchor" ## string offset=138
+ .asciz "U" ## string offset=151
+ .asciz "raw" ## string offset=153
+ .asciz "unsigned int" ## string offset=157
+ .asciz "a" ## string offset=170
+ .asciz "b" ## string offset=172
+ .asciz "c" ## string offset=174
+ .asciz "d" ## string offset=176
+ .asciz "e" ## string offset=178
+ .asciz "f" ## string offset=180
+ .asciz "ug" ## string offset=182
+ .section __DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+ .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
+ .ascii "\202|" ## DW_AT_LLVM_sysroot
+ .byte 14 ## DW_FORM_strp
+ .ascii "\357\177" ## DW_AT_APPLE_sdk
+ .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
+ .ascii "\341\177" ## DW_AT_APPLE_optimized
+ .byte 25 ## DW_FORM_flag_present
+ .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 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 22 ## DW_TAG_typedef
+ .byte 0 ## DW_CHILDREN_no
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 4 ## Abbreviation Code
+ .byte 23 ## DW_TAG_union_type
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 11 ## DW_AT_byte_size
+ .byte 11 ## DW_FORM_data1
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 5 ## 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 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 56 ## DW_AT_data_member_location
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 6 ## Abbreviation Code
+ .byte 13 ## DW_TAG_member
+ .byte 0 ## DW_CHILDREN_no
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 56 ## DW_AT_data_member_location
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 7 ## Abbreviation Code
+ .byte 19 ## DW_TAG_structure_type
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 11 ## DW_AT_byte_size
+ .byte 11 ## DW_FORM_data1
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 8 ## 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 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 13 ## DW_AT_bit_size
+ .byte 11 ## DW_FORM_data1
+ .byte 107 ## DW_AT_data_bit_offset
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 9 ## 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 0 ## EOM(3)
+ .section __DWARF,__debug_info,regular,debug
+Lsection_info:
+Lcu_begin0:
+.set Lset0, Ldebug_info_end0-Ldebug_info_start0 ## Length of Unit
+ .long Lset0
+Ldebug_info_start0:
+ .short 4 ## DWARF version number
+.set Lset1, Lsection_abbrev-Lsection_abbrev ## Offset Into Abbrev. Section
+ .long Lset1
+ .byte 8 ## Address Size (in bytes)
+ .byte 1 ## Abbrev [1] 0xb:0xd0 DW_TAG_compile_unit
+ .long 0 ## DW_AT_producer
+ .short 12 ## DW_AT_language
+ .long 47 ## DW_AT_name
+ .long 60 ## DW_AT_LLVM_sysroot
+ .long 117 ## DW_AT_APPLE_sdk
+ .long 0 ## DW_AT_stmt_list
+ .long 133 ## DW_AT_comp_dir
+ ## DW_AT_APPLE_optimized
+ .byte 2 ## Abbrev [2] 0x26:0x15 DW_TAG_variable
+ .long 138 ## DW_AT_name
+ .long 59 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 14 ## DW_AT_decl_line
+ .byte 9 ## DW_AT_location
+ .byte 3
+ .quad __type_anchor
+ .byte 3 ## Abbrev [3] 0x3b:0xb DW_TAG_typedef
+ .long 70 ## DW_AT_type
+ .long 151 ## DW_AT_name
+ .byte 1 ## DW_AT_decl_file
+ .byte 11 ## DW_AT_decl_line
+ .byte 4 ## Abbrev [4] 0x46:0x6c DW_TAG_union_type
+ .byte 4 ## DW_AT_byte_size
+ .byte 1 ## DW_AT_decl_file
+ .byte 1 ## DW_AT_decl_line
+ .byte 5 ## Abbrev [5] 0x4a:0xc DW_TAG_member
+ .long 153 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 2 ## DW_AT_decl_line
+ .byte 0 ## DW_AT_data_member_location
+ .byte 6 ## Abbrev [6] 0x56:0x8 DW_TAG_member
+ .long 94 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 3 ## DW_AT_decl_line
+ .byte 0 ## DW_AT_data_member_location
+ .byte 7 ## Abbrev [7] 0x5e:0x53 DW_TAG_structure_type
+ .byte 4 ## DW_AT_byte_size
+ .byte 1 ## DW_AT_decl_file
+ .byte 3 ## DW_AT_decl_line
+ .byte 8 ## Abbrev [8] 0x62:0xd DW_TAG_member
+ .long 170 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 4 ## DW_AT_decl_line
+ .byte 8 ## DW_AT_bit_size
+ .byte 0 ## DW_AT_data_bit_offset
+ .byte 8 ## Abbrev [8] 0x6f:0xd DW_TAG_member
+ .long 172 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 5 ## DW_AT_decl_line
+ .byte 8 ## DW_AT_bit_size
+ .byte 8 ## DW_AT_data_bit_offset
+ .byte 8 ## Abbrev [8] 0x7c:0xd DW_TAG_member
+ .long 174 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 6 ## DW_AT_decl_line
+ .byte 6 ## DW_AT_bit_size
+ .byte 16 ## DW_AT_data_bit_offset
+ .byte 8 ## Abbrev [8] 0x89:0xd DW_TAG_member
+ .long 176 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 7 ## DW_AT_decl_line
+ .byte 2 ## DW_AT_bit_size
+ .byte 22 ## DW_AT_data_bit_offset
+ .byte 8 ## Abbrev [8] 0x96:0xd DW_TAG_member
+ .long 178 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 8 ## DW_AT_decl_line
+ .byte 6 ## DW_AT_bit_size
+ .byte 24 ## DW_AT_data_bit_offset
+ .byte 8 ## Abbrev [8] 0xa3:0xd DW_TAG_member
+ .long 180 ## DW_AT_name
+ .long 178 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 9 ## DW_AT_decl_line
+ .byte 2 ## DW_AT_bit_size
+ .byte 30 ## DW_AT_data_bit_offset
+ .byte 0 ## End Of Children Mark
+ .byte 0 ## End Of Children Mark
+ .byte 9 ## Abbrev [9] 0xb2:0x7 DW_TAG_base_type
+ .long 157 ## DW_AT_name
+ .byte 7 ## DW_AT_encoding
+ .byte 4 ## DW_AT_byte_size
+ .byte 2 ## Abbrev [2] 0xb9:0x21 DW_TAG_variable
+ .long 182 ## DW_AT_name
+ .long 59 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 17 ## DW_AT_decl_line
+ .byte 7 ## DW_AT_location
+ .byte 16
+ .ascii "\201\202\220\245\006"
+ .byte 159
+ .byte 0 ## End Of Children Mark
+Ldebug_info_end0:
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