projects / platform / upstream / llvm.git / commitdiff
? search:
summary | shortlog | log | commit | commitdiff | tree
raw | patch | inline | side by side (parent: 62e91bf)
[LLDB] Fix how ValueObjectVariable handles DW_AT_const_value when the DWARFExpression...
authorshafik <syaghmour@apple.com>
Mon, 24 Aug 2020 21:38:55 +0000 (14:38 -0700)
committershafik <syaghmour@apple.com>
Mon, 24 Aug 2020 22:17:27 +0000 (15:17 -0700)
In some cases when we have a DW_AT_const_value and the data can be found in the
DWARFExpression then ValueObjectVariable does not handle it properly and we end
up with an extracting data from value failed error.

The test is a very stripped down assembly file since reproducing this relies on the results of compiling with -O1 which may not be stable over time.

Differential Revision: https://reviews.llvm.org/D86311

lldb/source/Core/ValueObjectVariable.cpp patch | blob | history
lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s [new file with mode: 0644] patch | blob

diff --git a/lldb/source/Core/ValueObjectVariable.cpp b/lldb/source/Core/ValueObjectVariable.cpp
index ab67e30..43e888a 100644 (file)
--- a/lldb/source/Core/ValueObjectVariable.cpp
+++ b/lldb/source/Core/ValueObjectVariable.cpp
@@ -132,8 +132,11 @@ bool ValueObjectVariable::UpdateValue() {
   if (variable->GetLocationIsConstantValueData()) {
     // expr doesn't contain DWARF bytes, it contains the constant variable
     // value bytes themselves...
-    if (expr.GetExpressionData(m_data))
+    if (expr.GetExpressionData(m_data)) {
+       if (m_data.GetDataStart() && m_data.GetByteSize())
+        m_value.SetBytes(m_data.GetDataStart(), m_data.GetByteSize());
       m_value.SetContext(Value::eContextTypeVariable, variable);
+    }
     else
       m_error.SetErrorString("empty constant data");
     // constant bytes can't be edited - sorry
diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s
new file mode 100644 (file)
index 0000000..09c369f
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s
@@ -0,0 +1,409 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-apple-macosx10.15.0 %s
+# RUN: %lldb %t -o "target variable constant" -b | FileCheck %s
+
+# CHECK: (lldb) target variable constant
+# CHECK: (U) constant = {
+# CHECK:   raw = 1688469761
+# CHECK:    = (a = 1, b = 1, c = 36, d = 2, e = 36, f = 1)
+# CHECK: }
+
+# Test we are able to display a variable whose value is given by DW_AT_const_value.
+# Compiling at -O1 allows us to capture this case. Below is the code used
+# to generate the assembly:
+#
+# typedef union
+# {
+#   unsigned raw;
+#   struct
+#   {
+#     unsigned a : 8;
+#     unsigned b : 8;
+#     unsigned c : 6;
+#     unsigned d : 2;
+#     unsigned e : 6;
+#     unsigned f : 2;
+#   } ;
+# } U;
+#
+# static U __attribute__((used)) _type_anchor;
+# static const int constant = 0x64A40101;
+#
+# int g() { return constant; }
+#
+# int main() {
+#   U u;
+#   u.raw = 0x64A40101;
+# }
+#
+# Compiled as follows:
+#
+#   clang -gdwarf-4 -O1 dw_at_const_value_bug.c -S -o dw_at_const_value_bug.s
+#
+# I was not able to obtain a global of type U with DW_AT_const_value but was able
+# to using int. This required modifying the DW_AT_type of constant to be type
+# U. After that stripping as much of the assembly as possible to give us a
+# smaller reproducer.
+
+
+.zerofill __DATA,__bss,__type_anchor,4,2 ## @_type_anchor
+       .no_dead_strip  __type_anchor
+       .section        __DWARF,__debug_str,regular,debug
+Linfo_string:
+  .zero 90
+       .asciz  "constant"              ## string offset=90
+       .asciz  "int"                   ## string offset=99
+       .asciz  "_type_anchor"          ## string offset=103
+       .asciz  "U"                     ## string offset=116
+       .asciz  "raw"                   ## string offset=118
+       .asciz  "unsigned int"          ## string offset=122
+       .asciz  "a"                     ## string offset=135
+       .asciz  "b"                     ## string offset=137
+       .asciz  "c"                     ## string offset=139
+       .asciz  "d"                     ## string offset=141
+       .asciz  "e"                     ## string offset=143
+       .asciz  "f"                     ## string offset=145
+       .asciz  "g"                     ## string offset=147
+       .asciz  "main"                  ## string offset=149
+       .asciz  "u"                     ## string offset=154
+       .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
+       .byte   66                      ## DW_AT_stmt_list
+       .byte   23                      ## DW_FORM_sec_offset
+       .byte   27                      ## DW_AT_comp_dir
+       .byte   14                      ## DW_FORM_strp
+       .ascii  "\264B"                 ## DW_AT_GNU_pubnames
+       .byte   25                      ## DW_FORM_flag_present
+       .ascii  "\341\177"              ## DW_AT_APPLE_optimized
+       .byte   25                      ## DW_FORM_flag_present
+       .byte   17                      ## DW_AT_low_pc
+       .byte   1                       ## DW_FORM_addr
+       .byte   18                      ## DW_AT_high_pc
+       .byte   6                       ## DW_FORM_data4
+       .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   28                      ## DW_AT_const_value
+       .byte   15                      ## DW_FORM_udata
+       .byte   0                       ## EOM(1)
+       .byte   0                       ## EOM(2)
+       .byte   3                       ## 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   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   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   6                       ## 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   7                       ## 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   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   56                      ## DW_AT_data_member_location
+       .byte   11                      ## DW_FORM_data1
+       .byte   0                       ## EOM(1)
+       .byte   0                       ## EOM(2)
+       .byte   9                       ## 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   10                      ## 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   11                      ## 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   12                      ## Abbreviation Code
+       .byte   46                      ## DW_TAG_subprogram
+       .byte   0                       ## DW_CHILDREN_no
+       .byte   17                      ## DW_AT_low_pc
+       .byte   1                       ## DW_FORM_addr
+       .byte   18                      ## DW_AT_high_pc
+       .byte   6                       ## DW_FORM_data4
+       .byte   64                      ## DW_AT_frame_base
+       .byte   24                      ## DW_FORM_exprloc
+       .byte   122                     ## DW_AT_call_all_calls
+       .byte   25                      ## DW_FORM_flag_present
+       .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   73                      ## DW_AT_type
+       .byte   19                      ## DW_FORM_ref4
+       .byte   63                      ## DW_AT_external
+       .byte   25                      ## DW_FORM_flag_present
+       .ascii  "\341\177"              ## DW_AT_APPLE_optimized
+       .byte   25                      ## DW_FORM_flag_present
+       .byte   0                       ## EOM(1)
+       .byte   0                       ## EOM(2)
+       .byte   13                      ## Abbreviation Code
+       .byte   46                      ## DW_TAG_subprogram
+       .byte   1                       ## DW_CHILDREN_yes
+       .byte   17                      ## DW_AT_low_pc
+       .byte   1                       ## DW_FORM_addr
+       .byte   18                      ## DW_AT_high_pc
+       .byte   6                       ## DW_FORM_data4
+       .byte   64                      ## DW_AT_frame_base
+       .byte   24                      ## DW_FORM_exprloc
+       .byte   122                     ## DW_AT_call_all_calls
+       .byte   25                      ## DW_FORM_flag_present
+       .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   73                      ## DW_AT_type
+       .byte   19                      ## DW_FORM_ref4
+       .byte   63                      ## DW_AT_external
+       .byte   25                      ## DW_FORM_flag_present
+       .ascii  "\341\177"              ## DW_AT_APPLE_optimized
+       .byte   25                      ## DW_FORM_flag_present
+       .byte   0                       ## EOM(1)
+       .byte   0                       ## EOM(2)
+       .byte   14                      ## Abbreviation Code
+       .byte   52                      ## DW_TAG_variable
+       .byte   0                       ## DW_CHILDREN_no
+       .byte   28                      ## DW_AT_const_value
+       .byte   15                      ## DW_FORM_udata
+       .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   73                      ## DW_AT_type
+       .byte   19                      ## DW_FORM_ref4
+       .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:0x112 DW_TAG_compile_unit
+       .long   0                       ## DW_AT_producer
+       .short  12                      ## DW_AT_language
+       .long   47                      ## DW_AT_name
+       .long 0                       ## DW_AT_stmt_list
+       .long   71                      ## DW_AT_comp_dir
+                                        ## DW_AT_GNU_pubnames
+                                        ## DW_AT_APPLE_optimized
+       .quad   0            ## DW_AT_low_pc
+       .long 0
+       .byte   2                       ## Abbrev [2] 0x2a:0x10 DW_TAG_variable
+       .long   90                      ## DW_AT_name
+       .long   91                      ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   16                      ## DW_AT_decl_line
+       .ascii  "\201\202\220\245\006"  ## DW_AT_const_value
+       .byte   3                       ## Abbrev [3] 0x3a:0x5 DW_TAG_const_type
+       .long   63                      ## DW_AT_type
+       .byte   4                       ## Abbrev [4] 0x3f:0x7 DW_TAG_base_type
+       .long   99                      ## DW_AT_name
+       .byte   5                       ## DW_AT_encoding
+       .byte   4                       ## DW_AT_byte_size
+       .byte   5                       ## Abbrev [5] 0x46:0x15 DW_TAG_variable
+       .long   103                     ## DW_AT_name
+       .long   91                      ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   15                      ## DW_AT_decl_line
+       .byte   9                       ## DW_AT_location
+       .byte   3
+       .quad   __type_anchor
+       .byte   6                       ## Abbrev [6] 0x5b:0xb DW_TAG_typedef
+       .long   102                     ## DW_AT_type
+       .long   116                     ## DW_AT_name
+       .byte   1                       ## DW_AT_decl_file
+       .byte   13                      ## DW_AT_decl_line
+       .byte   7                       ## Abbrev [7] 0x66:0x6c DW_TAG_union_type
+       .byte   4                       ## DW_AT_byte_size
+       .byte   1                       ## DW_AT_decl_file
+       .byte   1                       ## DW_AT_decl_line
+       .byte   8                       ## Abbrev [8] 0x6a:0xc DW_TAG_member
+       .long   118                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   3                       ## DW_AT_decl_line
+       .byte   0                       ## DW_AT_data_member_location
+       .byte   9                       ## Abbrev [9] 0x76:0x8 DW_TAG_member
+       .long   126                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   4                       ## DW_AT_decl_line
+       .byte   0                       ## DW_AT_data_member_location
+       .byte   10                      ## Abbrev [10] 0x7e:0x53 DW_TAG_structure_type
+       .byte   4                       ## DW_AT_byte_size
+       .byte   1                       ## DW_AT_decl_file
+       .byte   4                       ## DW_AT_decl_line
+       .byte   11                      ## Abbrev [11] 0x82:0xd DW_TAG_member
+       .long   135                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   6                       ## DW_AT_decl_line
+       .byte   8                       ## DW_AT_bit_size
+       .byte   0                       ## DW_AT_data_bit_offset
+       .byte   11                      ## Abbrev [11] 0x8f:0xd DW_TAG_member
+       .long   137                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   7                       ## DW_AT_decl_line
+       .byte   8                       ## DW_AT_bit_size
+       .byte   8                       ## DW_AT_data_bit_offset
+       .byte   11                      ## Abbrev [11] 0x9c:0xd DW_TAG_member
+       .long   139                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   8                       ## DW_AT_decl_line
+       .byte   6                       ## DW_AT_bit_size
+       .byte   16                      ## DW_AT_data_bit_offset
+       .byte   11                      ## Abbrev [11] 0xa9:0xd DW_TAG_member
+       .long   141                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   9                       ## DW_AT_decl_line
+       .byte   2                       ## DW_AT_bit_size
+       .byte   22                      ## DW_AT_data_bit_offset
+       .byte   11                      ## Abbrev [11] 0xb6:0xd DW_TAG_member
+       .long   143                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   10                      ## DW_AT_decl_line
+       .byte   6                       ## DW_AT_bit_size
+       .byte   24                      ## DW_AT_data_bit_offset
+       .byte   11                      ## Abbrev [11] 0xc3:0xd DW_TAG_member
+       .long   145                     ## DW_AT_name
+       .long   210                     ## DW_AT_type
+       .byte   1                       ## DW_AT_decl_file
+       .byte   11                      ## 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   4                       ## Abbrev [4] 0xd2:0x7 DW_TAG_base_type
+       .long   122                     ## DW_AT_name
+       .byte   7                       ## DW_AT_encoding
+       .byte   4                       ## DW_AT_byte_size
+       .byte   14                      ## Abbrev [14] 0x10b:0x10 DW_TAG_variable
+       .ascii  "\201\202\220\245\006"  ## DW_AT_const_value
+       .long   154                     ## DW_AT_name
+       .byte   1                       ## DW_AT_decl_file
+       .byte   21                      ## DW_AT_decl_line
+       .long   91                      ## DW_AT_type
+       .byte   0                       ## End Of Children Mark
+       .byte   0                       ## End Of Children Mark
+Ldebug_info_end0:
Domain: System / Toolchain;