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[lldb/DWARF] Fix mixed v4+v5 location lists

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Summary:
Our code was expecting that a single (symbol) file contains only one
kind of location lists. This is not correct (on non-apple platforms, at
least) as a file can compile units with different dwarf versions.

This patch moves the deteremination of location list flavour down to the
compile unit level, fixing this problem. I have also tried to rougly
align the code with the llvm DWARFUnit. Fully matching the API is not
possible because of how lldb's DWARFExpression lives separately from the
rest of the DWARF code, but this is at least a step in the right
direction.

Reviewers: JDevlieghere, aprantl, clayborg

Subscribers: dblaikie, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71751
This commit is contained in:
Pavel Labath 2019-12-20 09:42:37 +01:00
parent 9bb01efa49
commit cd5da94d80
10 changed files with 184 additions and 75 deletions
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9
lldb/include/lldb/Expression/DWARFExpression.h
View File

@ -34,15 +34,6 @@ namespace lldb_private {
/// location expression or a location list and interprets it.
class DWARFExpression {
public:
enum LocationListFormat : uint8_t {
NonLocationList, // Not a location list
RegularLocationList, // Location list format used in non-split dwarf files
SplitDwarfLocationList, // Location list format used in pre-DWARF v5 split
// dwarf files (.debug_loc.dwo)
LocLists, // Location list format used in DWARF v5
// (.debug_loclists/.debug_loclists.dwo).
};
DWARFExpression();
/// Constructor

35
lldb/source/Expression/DWARFExpression.cpp
View File

@ -54,29 +54,6 @@ ReadAddressFromDebugAddrSection(const DWARFUnit *dwarf_cu,
return LLDB_INVALID_ADDRESS;
}
/// Return the location list parser for the given format.
static std::unique_ptr<llvm::DWARFLocationTable>
GetLocationTable(DWARFExpression::LocationListFormat format, const DataExtractor &data) {
llvm::DWARFDataExtractor llvm_data(
toStringRef(data.GetData()),
data.GetByteOrder() == lldb::eByteOrderLittle, data.GetAddressByteSize());
switch (format) {
case DWARFExpression::NonLocationList:
return nullptr;
// DWARF<=4 .debug_loc
case DWARFExpression::RegularLocationList:
return std::make_unique<llvm::DWARFDebugLoc>(llvm_data);
// Non-standard DWARF 4 extension (fission) .debug_loc.dwo
case DWARFExpression::SplitDwarfLocationList:
// DWARF 5 .debug_loclists(.dwo)
case DWARFExpression::LocLists:
return std::make_unique<llvm::DWARFDebugLoclists>(
llvm_data, format == DWARFExpression::LocLists ? 5 : 4);
}
llvm_unreachable("Invalid LocationListFormat!");
}
// DWARFExpression constructor
DWARFExpression::DWARFExpression()
: m_module_wp(), m_data(), m_dwarf_cu(nullptr),
@ -157,10 +134,8 @@ void DWARFExpression::GetDescription(Stream *s, lldb::DescriptionLevel level,
if (IsLocationList()) {
// We have a location list
lldb::offset_t offset = 0;
std::unique_ptr<llvm::DWARFLocationTable> loctable_up = GetLocationTable(
m_dwarf_cu->GetSymbolFileDWARF().GetLocationListFormat(), m_data);
if (!loctable_up)
return;
std::unique_ptr<llvm::DWARFLocationTable> loctable_up =
m_dwarf_cu->GetLocationTable(m_data);
llvm::MCRegisterInfo *MRI = abi ? &abi->GetMCRegisterInfo() : nullptr;
@ -2812,10 +2787,8 @@ DWARFExpression::GetLocationExpression(addr_t load_function_start,
addr_t addr) const {
Log *log = GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS);
std::unique_ptr<llvm::DWARFLocationTable> loctable_up = GetLocationTable(
m_dwarf_cu->GetSymbolFileDWARF().GetLocationListFormat(), m_data);
if (!loctable_up)
return llvm::None;
std::unique_ptr<llvm::DWARFLocationTable> loctable_up =
m_dwarf_cu->GetLocationTable(m_data);
llvm::Optional<DataExtractor> result;
uint64_t offset = 0;
auto lookup_addr =

6
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
View File

@ -344,7 +344,7 @@ bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
*frame_base = DWARFExpression(
module, DataExtractor(data, block_offset, block_length), cu);
} else {
DataExtractor data = dwarf.DebugLocData();
DataExtractor data = cu->GetLocationData();
const dw_offset_t offset = form_value.Unsigned();
if (data.ValidOffset(offset)) {
data = DataExtractor(data, offset, data.GetByteSize() - offset);
@ -478,8 +478,6 @@ void DWARFDebugInfoEntry::DumpAttribute(
s.PutCString("( ");
SymbolFileDWARF &dwarf = cu->GetSymbolFileDWARF();
// Check to see if we have any special attribute formatters
switch (attr) {
case DW_AT_stmt_list:
@ -509,7 +507,7 @@ void DWARFDebugInfoEntry::DumpAttribute(
// We have a location list offset as the value that is the offset into
// the .debug_loc section that describes the value over it's lifetime
uint64_t debug_loc_offset = form_value.Unsigned();
DWARFExpression::PrintDWARFLocationList(s, cu, dwarf.DebugLocData(),
DWARFExpression::PrintDWARFLocationList(s, cu, cu->GetLocationData(),
debug_loc_offset);
}
} break;

16
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
View File

@ -462,6 +462,22 @@ void DWARFUnit::SetLoclistsBase(dw_addr_t loclists_base) {
}
}
std::unique_ptr<llvm::DWARFLocationTable>
DWARFUnit::GetLocationTable(const DataExtractor &data) const {
llvm::DWARFDataExtractor llvm_data(
toStringRef(data.GetData()),
data.GetByteOrder() == lldb::eByteOrderLittle, data.GetAddressByteSize());
if (m_is_dwo || GetVersion() >= 5)
return std::make_unique<llvm::DWARFDebugLoclists>(llvm_data, GetVersion());
return std::make_unique<llvm::DWARFDebugLoc>(llvm_data);
}
const DWARFDataExtractor &DWARFUnit::GetLocationData() const {
return GetVersion() >= 5 ? GetSymbolFileDWARF().get_debug_loclists_data()
: GetSymbolFileDWARF().get_debug_loc_data();
}
void DWARFUnit::SetRangesBase(dw_addr_t ranges_base) {
m_ranges_base = ranges_base;

7
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
View File

@ -243,6 +243,13 @@ public:
return *Offset + m_loclists_base;
}
/// Return the location table for parsing the given location list data. The
/// format is chosen according to the unit type. Never returns null.
std::unique_ptr<llvm::DWARFLocationTable>
GetLocationTable(const lldb_private::DataExtractor &data) const;
const lldb_private::DWARFDataExtractor &GetLocationData() const;
protected:
DWARFUnit(SymbolFileDWARF &dwarf, lldb::user_id_t uid,
const DWARFUnitHeader &header,

16
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
View File

@ -597,13 +597,6 @@ void SymbolFileDWARF::LoadSectionData(lldb::SectionType sect_type,
m_objfile_sp->ReadSectionData(section_sp.get(), data);
}
const DWARFDataExtractor &SymbolFileDWARF::DebugLocData() {
const DWARFDataExtractor &debugLocData = get_debug_loc_data();
if (debugLocData.GetByteSize() > 0)
return debugLocData;
return get_debug_loclists_data();
}
const DWARFDataExtractor &SymbolFileDWARF::get_debug_loc_data() {
return GetCachedSectionData(eSectionTypeDWARFDebugLoc, m_data_debug_loc);
}
@ -3361,7 +3354,7 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
module, DataExtractor(data, block_offset, block_length),
die.GetCU());
} else {
DataExtractor data = DebugLocData();
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);
@ -3978,13 +3971,6 @@ SymbolFileDWARFDebugMap *SymbolFileDWARF::GetDebugMapSymfile() {
return m_debug_map_symfile;
}
DWARFExpression::LocationListFormat
SymbolFileDWARF::GetLocationListFormat() const {
if (m_data_debug_loclists.m_data.GetByteSize() > 0)
return DWARFExpression::LocLists;
return DWARFExpression::RegularLocationList;
}
SymbolFileDWARFDwp *SymbolFileDWARF::GetDwpSymbolFile() {
llvm::call_once(m_dwp_symfile_once_flag, [this]() {
ModuleSpec module_spec;

6
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
View File

@ -21,7 +21,6 @@
#include "lldb/Core/UniqueCStringMap.h"
#include "lldb/Core/dwarf.h"
#include "lldb/Expression/DWARFExpression.h"
#include "lldb/Symbol/DebugMacros.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/SymbolFile.h"
@ -236,8 +235,6 @@ public:
DWARFDebugRanges *GetDebugRanges();
const lldb_private::DWARFDataExtractor &DebugLocData();
static bool SupportedVersion(uint16_t version);
DWARFDIE
@ -260,9 +257,6 @@ public:
virtual lldb::CompUnitSP ParseCompileUnit(DWARFCompileUnit &dwarf_cu);
virtual lldb_private::DWARFExpression::LocationListFormat
GetLocationListFormat() const;
lldb::ModuleSP GetExternalModule(lldb_private::ConstString name);
typedef std::map<lldb_private::ConstString, lldb::ModuleSP>

7
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
View File

@ -137,13 +137,6 @@ SymbolFileDWARF &SymbolFileDWARFDwo::GetBaseSymbolFile() {
return m_base_dwarf_cu.GetSymbolFileDWARF();
}
DWARFExpression::LocationListFormat
SymbolFileDWARFDwo::GetLocationListFormat() const {
return m_base_dwarf_cu.GetVersion() >= 5
? DWARFExpression::LocLists
: DWARFExpression::SplitDwarfLocationList;
}
llvm::Expected<TypeSystem &>
SymbolFileDWARFDwo::GetTypeSystemForLanguage(LanguageType language) {
return GetBaseSymbolFile().GetTypeSystemForLanguage(language);

3
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
View File

@ -35,9 +35,6 @@ public:
DWARFUnit *
GetDWARFCompileUnit(lldb_private::CompileUnit *comp_unit) override;
lldb_private::DWARFExpression::LocationListFormat
GetLocationListFormat() const override;
size_t GetObjCMethodDIEOffsets(lldb_private::ConstString class_name,
DIEArray &method_die_offsets) override;

154
lldb/test/Shell/SymbolFile/DWARF/debug_loc_and_loclists.s Normal file
View File

@ -0,0 +1,154 @@
# Test that we can handle DWARF 4 and 5 location lists in the same object file
# (but different compile units).
# REQUIRES: x86
# RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj %s > %t
# RUN: %lldb %t -o "image lookup -v -s loc" -o "image lookup -v -s loclists" \
# RUN: -o exit | FileCheck %s
# CHECK-LABEL: image lookup -v -s loc
# CHECK: Variable: {{.*}}, name = "x0", type = "int", location = DW_OP_reg5 RDI,
# CHECK-LABEL: image lookup -v -s loclists
# CHECK: Variable: {{.*}}, name = "x1", type = "int", location = DW_OP_reg0 RAX,
loc:
nop
.Lloc_end:
loclists:
nop
.Lloclists_end:
.section .debug_loc,"",@progbits
.Lloc_list:
.quad loc-loc
.quad .Lloc_end-loc
.short 1
.byte 85 # super-register DW_OP_reg5
.quad 0
.quad 0
.section .debug_loclists,"",@progbits
.long .Ldebug_loclist_table_end0-.Ldebug_loclist_table_start0 # Length
.Ldebug_loclist_table_start0:
.short 5 # Version
.byte 8 # Address size
.byte 0 # Segment selector size
.long 0 # Offset entry count
.Lloclists_list:
.byte 4 # DW_LLE_offset_pair
.uleb128 loclists-loclists
.uleb128 .Lloclists_end-loclists
.uleb128 1
.byte 80 # super-register DW_OP_reg0
.byte 0 # DW_LLE_end_of_list
.Ldebug_loclist_table_end0:
.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 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 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 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 73 # DW_AT_type
.byte 16 # DW_FORM_ref_addr
.byte 0 # EOM(1)
.byte 0 # EOM(2)
.byte 3 # Abbreviation Code
.byte 5 # DW_TAG_formal_parameter
.byte 0 # DW_CHILDREN_no
.byte 2 # DW_AT_location
.byte 23 # DW_FORM_sec_offset
.byte 3 # DW_AT_name
.byte 8 # DW_FORM_string
.byte 73 # DW_AT_type
.byte 16 # DW_FORM_ref_addr
.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 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 0 # EOM(3)
.section .debug_info,"",@progbits
.long .Lloc_cu_end-.Lloc_cu_start # Length of Unit
.Lloc_cu_start:
.short 4 # DWARF version number
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 8 # Address Size (in bytes)
.byte 1 # Abbrev [1] 0xb:0x50 DW_TAG_compile_unit
.asciz "Hand-written DWARF" # DW_AT_producer
.short 12 # DW_AT_language
.quad loc # DW_AT_low_pc
.long .Lloc_end-loc # DW_AT_high_pc
.byte 2 # Abbrev [2] 0x2a:0x29 DW_TAG_subprogram
.quad loc # DW_AT_low_pc
.long .Lloc_end-loc # DW_AT_high_pc
.asciz "loc" # DW_AT_name
.long .Lint # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long .Lloc_list # DW_AT_location
.asciz "x0" # DW_AT_name
.long .Lint # DW_AT_type
.byte 0 # End Of Children Mark
.Lint:
.byte 4 # Abbrev [4] 0x53:0x7 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
.Lloc_cu_end:
.long .Lloclists_cu_end-.Lloclists_cu_start # Length of Unit
.Lloclists_cu_start:
.short 5 # DWARF version number
.byte 1 # DWARF Unit Type
.byte 8 # Address Size (in bytes)
.long .debug_abbrev # Offset Into Abbrev. Section
.byte 1 # Abbrev [1] 0xb:0x50 DW_TAG_compile_unit
.asciz "Hand-written DWARF" # DW_AT_producer
.short 12 # DW_AT_language
.quad loclists # DW_AT_low_pc
.long .Lloclists_end-loclists # DW_AT_high_pc
.byte 2 # Abbrev [2] 0x2a:0x29 DW_TAG_subprogram
.quad loclists # DW_AT_low_pc
.long .Lloclists_end-loclists # DW_AT_high_pc
.asciz "loclists" # DW_AT_name
.long .Lint # DW_AT_type
.byte 3 # Abbrev [3] DW_TAG_formal_parameter
.long .Lloclists_list # DW_AT_location
.asciz "x1" # DW_AT_name
.long .Lint # DW_AT_type
.byte 0 # End Of Children Mark
.byte 0 # End Of Children Mark
.Lloclists_cu_end: