This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG9f5927e42bf4: [lldb/DWARF] Fix handling of variables with
both location and const_value… (authored by labath).
Changed prior to commit:
https://reviews.llvm.org/D86615?vs=287940&id=288303#toc
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D86615/new/
https://reviews.llvm.org/D86615
Files:
lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
lldb/test/Shell/SymbolFile/DWARF/DW_AT_location-DW_AT_const_value.s
Index: lldb/test/Shell/SymbolFile/DWARF/DW_AT_location-DW_AT_const_value.s
===================================================================
--- /dev/null
+++ lldb/test/Shell/SymbolFile/DWARF/DW_AT_location-DW_AT_const_value.s
@@ -0,0 +1,144 @@
+## Test that we don't get confused by variables with both location and
+## const_value attributes. Such values are produced in C++ for class-level
+## static constexpr variables.
+
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux %s -o %t
+# RUN: %lldb %t -o "target variable A::x A::y" -o exit | FileCheck %s
+
+# CHECK-LABEL: target variable
+# CHECK: (const int) A::x = 142
+# CHECK: (const int) A::y = 242
+
+ .section .rodata,"a",@progbits
+ .p2align 2
+_ZN1A1xE:
+ .long 142
+_ZN1A1yE:
+ .long 242
+
+ .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 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 3 # Abbreviation Code
+ .byte 19 # DW_TAG_structure_type
+ .byte 1 # DW_CHILDREN_yes
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 11 # DW_AT_byte_size
+ .byte 11 # DW_FORM_data1
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+ .byte 4 # Abbreviation Code
+ .byte 13 # DW_TAG_member
+ .byte 0 # DW_CHILDREN_no
+ .byte 3 # DW_AT_name
+ .byte 8 # DW_FORM_string
+ .byte 73 # DW_AT_type
+ .byte 19 # DW_FORM_ref4
+ .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
+ .byte 8 # DW_FORM_string
+ .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 7 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 71 # DW_AT_specification
+ .byte 19 # DW_FORM_ref4
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 110 # DW_AT_linkage_name
+ .byte 8 # DW_FORM_string
+ .byte 0 # EOM(1)
+ .byte 0 # EOM(2)
+## This deliberately inverts the order of the specification and location
+## attributes.
+ .byte 8 # Abbreviation Code
+ .byte 52 # DW_TAG_variable
+ .byte 0 # DW_CHILDREN_no
+ .byte 2 # DW_AT_location
+ .byte 24 # DW_FORM_exprloc
+ .byte 71 # DW_AT_specification
+ .byte 19 # DW_FORM_ref4
+ .byte 110 # DW_AT_linkage_name
+ .byte 8 # DW_FORM_string
+ .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 DW_TAG_compile_unit
+ .asciz "Hand-written DWARF" # DW_AT_producer
+ .asciz "a.cc" # DW_AT_name
+ .byte 7 # Abbrev DW_TAG_variable
+ .long .LA__x-.Lcu_begin0 # DW_AT_specification
+ .byte 9 # DW_AT_location
+ .byte 3
+ .quad _ZN1A1xE
+ .asciz "_ZN1A1xE" # DW_AT_linkage_name
+ .byte 8 # Abbrev DW_TAG_variable
+ .byte 9 # DW_AT_location
+ .byte 3
+ .quad _ZN1A1yE
+ .long .LA__y-.Lcu_begin0 # DW_AT_specification
+ .asciz "_ZN1A1yE" # DW_AT_linkage_name
+ .byte 3 # Abbrev DW_TAG_structure_type
+ .asciz "A" # DW_AT_name
+ .byte 1 # DW_AT_byte_size
+.LA__x:
+ .byte 4 # Abbrev DW_TAG_member
+ .asciz "x" # DW_AT_name
+ .long .Lconst_int-.Lcu_begin0 # DW_AT_type
+ # DW_AT_declaration
+ .sleb128 147 # DW_AT_const_value
+.LA__y:
+ .byte 4 # Abbrev DW_TAG_member
+ .asciz "y" # DW_AT_name
+ .long .Lconst_int-.Lcu_begin0 # DW_AT_type
+ # DW_AT_declaration
+ .sleb128 247 # DW_AT_const_value
+ .byte 0 # End Of Children Mark
+.Lconst_int:
+ .byte 5 # Abbrev DW_TAG_const_type
+ .long .Lint-.Lcu_begin0 # DW_AT_type
+.Lint:
+ .byte 6 # Abbrev DW_TAG_base_type
+ .asciz "int" # DW_AT_name
+ .byte 5 # DW_AT_encoding
+ .byte 4 # DW_AT_byte_size
+ .byte 0 # End Of Children Mark
+.Ldebug_info_end0:
Index: lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -3111,18 +3111,15 @@
const char *name = nullptr;
const char *mangled = nullptr;
Declaration decl;
- uint32_t i;
DWARFFormValue type_die_form;
DWARFExpression location;
bool is_external = false;
bool is_artificial = false;
- bool location_is_const_value_data = false;
- bool has_explicit_location = false;
- DWARFFormValue const_value;
+ DWARFFormValue const_value_form, location_form;
Variable::RangeList scope_ranges;
// AccessType accessibility = eAccessNone;
- for (i = 0; i < num_attributes; ++i) {
+ for (size_t i = 0; i < num_attributes; ++i) {
dw_attr_t attr = attributes.AttributeAtIndex(i);
DWARFFormValue form_value;
@@ -3152,65 +3149,11 @@
is_external = form_value.Boolean();
break;
case DW_AT_const_value:
- // If we have already found a DW_AT_location attribute, ignore this
- // attribute.
- if (!has_explicit_location) {
- location_is_const_value_data = true;
- // The constant value will be either a block, a data value or a
- // string.
- auto debug_info_data = die.GetData();
- if (DWARFFormValue::IsBlockForm(form_value.Form())) {
- // Retrieve the value as a block expression.
- uint32_t block_offset =
- form_value.BlockData() - debug_info_data.GetDataStart();
- uint32_t block_length = form_value.Unsigned();
- location = DWARFExpression(
- module,
- DataExtractor(debug_info_data, block_offset, block_length),
- die.GetCU());
- } else if (DWARFFormValue::IsDataForm(form_value.Form())) {
- // Constant value size does not have to match the size of the
- // variable. We will fetch the size of the type after we create
- // it.
- const_value = form_value;
- } else if (const char *str = form_value.AsCString()) {
- uint32_t string_length = strlen(str) + 1;
- location = DWARFExpression(
- module,
- DataExtractor(str, string_length,
- die.GetCU()->GetByteOrder(),
- die.GetCU()->GetAddressByteSize()),
- die.GetCU());
- }
- }
+ const_value_form = form_value;
+ break;
+ case DW_AT_location:
+ location_form = form_value;
break;
- case DW_AT_location: {
- location_is_const_value_data = false;
- has_explicit_location = true;
- if (DWARFFormValue::IsBlockForm(form_value.Form())) {
- auto data = die.GetData();
-
- uint32_t block_offset =
- form_value.BlockData() - data.GetDataStart();
- uint32_t block_length = form_value.Unsigned();
- location = DWARFExpression(
- module, DataExtractor(data, block_offset, block_length),
- die.GetCU());
- } else {
- DataExtractor data = die.GetCU()->GetLocationData();
- dw_offset_t offset = form_value.Unsigned();
- if (form_value.Form() == DW_FORM_loclistx)
- offset = die.GetCU()->GetLoclistOffset(offset).getValueOr(-1);
- if (data.ValidOffset(offset)) {
- data = DataExtractor(data, offset, data.GetByteSize() - offset);
- location = DWARFExpression(module, data, die.GetCU());
- assert(func_low_pc != LLDB_INVALID_ADDRESS);
- location.SetLocationListAddresses(
- attributes.CompileUnitAtIndex(i)->GetBaseAddress(),
- func_low_pc);
- }
- }
- } break;
case DW_AT_specification:
spec_die = form_value.Reference();
break;
@@ -3236,6 +3179,66 @@
}
}
+ // Prefer DW_AT_location over DW_AT_const_value. Both can be emitted e.g.
+ // for static constexpr member variables -- DW_AT_const_value will be
+ // present in the class declaration and DW_AT_location in the DIE defining
+ // the member.
+ bool location_is_const_value_data = false;
+ bool has_explicit_location = false;
+ bool use_type_size_for_value = false;
+ if (location_form.IsValid()) {
+ has_explicit_location = true;
+ if (DWARFFormValue::IsBlockForm(location_form.Form())) {
+ const DWARFDataExtractor &data = die.GetData();
+
+ uint32_t block_offset =
+ location_form.BlockData() - data.GetDataStart();
+ uint32_t block_length = location_form.Unsigned();
+ location = DWARFExpression(
+ module, DataExtractor(data, block_offset, block_length),
+ die.GetCU());
+ } else {
+ DataExtractor data = die.GetCU()->GetLocationData();
+ dw_offset_t offset = location_form.Unsigned();
+ if (location_form.Form() == DW_FORM_loclistx)
+ offset = die.GetCU()->GetLoclistOffset(offset).getValueOr(-1);
+ if (data.ValidOffset(offset)) {
+ data = DataExtractor(data, offset, data.GetByteSize() - offset);
+ location = DWARFExpression(module, data, die.GetCU());
+ assert(func_low_pc != LLDB_INVALID_ADDRESS);
+ location.SetLocationListAddresses(
+ location_form.GetUnit()->GetBaseAddress(), func_low_pc);
+ }
+ }
+ } else if (const_value_form.IsValid()) {
+ location_is_const_value_data = true;
+ // The constant value will be either a block, a data value or a
+ // string.
+ const DWARFDataExtractor &debug_info_data = die.GetData();
+ if (DWARFFormValue::IsBlockForm(const_value_form.Form())) {
+ // Retrieve the value as a block expression.
+ uint32_t block_offset =
+ const_value_form.BlockData() - debug_info_data.GetDataStart();
+ uint32_t block_length = const_value_form.Unsigned();
+ location = DWARFExpression(
+ module,
+ DataExtractor(debug_info_data, block_offset, block_length),
+ die.GetCU());
+ } else if (DWARFFormValue::IsDataForm(const_value_form.Form())) {
+ // Constant value size does not have to match the size of the
+ // variable. We will fetch the size of the type after we create
+ // it.
+ use_type_size_for_value = true;
+ } else if (const char *str = const_value_form.AsCString()) {
+ uint32_t string_length = strlen(str) + 1;
+ location = DWARFExpression(
+ module,
+ DataExtractor(str, string_length, die.GetCU()->GetByteOrder(),
+ die.GetCU()->GetAddressByteSize()),
+ die.GetCU());
+ }
+ }
+
const DWARFDIE parent_context_die = GetDeclContextDIEContainingDIE(die);
const dw_tag_t parent_tag = die.GetParent().Tag();
bool is_static_member =
@@ -3415,12 +3418,12 @@
}
if (symbol_context_scope) {
- SymbolFileTypeSP type_sp(
- new SymbolFileType(*this, GetUID(type_die_form.Reference())));
+ auto type_sp = std::make_shared<SymbolFileType>(
+ *this, GetUID(type_die_form.Reference()));
- if (const_value.Form() && type_sp && type_sp->GetType())
+ if (use_type_size_for_value && type_sp->GetType())
location.UpdateValue(
- const_value.Unsigned(),
+ const_value_form.Unsigned(),
type_sp->GetType()->GetByteSize(nullptr).getValueOr(0),
die.GetCU()->GetAddressByteSize());
Index: lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
+++ lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
@@ -42,6 +42,7 @@
DWARFFormValue(const DWARFUnit *unit) : m_unit(unit) {}
DWARFFormValue(const DWARFUnit *unit, dw_form_t form)
: m_unit(unit), m_form(form) {}
+ const DWARFUnit *GetUnit() const { return m_unit; }
void SetUnit(const DWARFUnit *unit) { m_unit = unit; }
dw_form_t Form() const { return m_form; }
dw_form_t& FormRef() { return m_form; }
_______________________________________________
lldb-commits mailing list
lldb-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
