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Cleanup fixed form sizes. 

The fix form sizes use to have two arrays: one for 4 byte addresses and in for 8 byte addresses. The table had an issue where DW_FORM_flag_present wasn't being represented as a fixed size form because its actual size _is_ zero and zero was used to indicate the form isn't fixed in size. Any code that needed to quickly access the DWARF had to get a FixedFormSizes instance using the address byte size.

This fix cleans things up by adding a DWARFFormValue::GetFixedSize() both as a static method and as a member function on DWARFFormValue. It correctly can indicate if a form size is zero. This cleanup is a precursor to a follow up patch where I hope to speed up DWARF parsing.

I verified performance doesn't regress by loading hundreds of DWARF files and setting a breakpoint by file and line and by name in files that do not have DWARF indexes. Performance remained consistent between the two approaches.


Differential Revision: https://reviews.llvm.org/D62416

llvm-svn: 361675
This commit is contained in:
Greg Clayton 2019-05-24 22:08:50 +00:00
parent b4c756dc1c
commit 6aad81cd96
11 changed files with 87 additions and 162 deletions
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8
lldb/lldb.xcodeproj/xcshareddata/xcschemes/desktop.xcscheme
View File

@ -45,7 +45,7 @@
buildConfiguration = "DebugClang"
selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
launchStyle = "1"
launchStyle = "0"
useCustomWorkingDirectory = "NO"
ignoresPersistentStateOnLaunch = "NO"
debugDocumentVersioning = "YES"
@ -61,6 +61,12 @@
ReferencedContainer = "container:lldb.xcodeproj">
</BuildableReference>
</BuildableProductRunnable>
<CommandLineArguments>
<CommandLineArgument
argument = "~/Documents/src/args/a.out "
isEnabled = "YES">
</CommandLineArgument>
</CommandLineArguments>
<AdditionalOptions>
</AdditionalOptions>
</LaunchAction>

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

@ -136,10 +136,8 @@ bool DWARFBaseDIE::Supports_DW_AT_APPLE_objc_complete_type() const {
size_t DWARFBaseDIE::GetAttributes(DWARFAttributes &attributes,
uint32_t depth) const {
if (IsValid()) {
return m_die->GetAttributes(m_cu, m_cu->GetFixedFormSizes(), attributes,
depth);
}
if (IsValid())
return m_die->GetAttributes(m_cu, attributes, depth);
if (depth == 0)
attributes.Clear();
return 0;

21
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
View File

@ -33,7 +33,6 @@ extern int g_verbose;
bool DWARFDebugInfoEntry::FastExtract(
const DWARFDataExtractor &debug_info_data, const DWARFUnit *cu,
const DWARFFormValue::FixedFormSizes &fixed_form_sizes,
lldb::offset_t *offset_ptr) {
m_offset = *offset_ptr;
m_parent_idx = 0;
@ -69,9 +68,9 @@ bool DWARFDebugInfoEntry::FastExtract(
for (i = 0; i < numAttributes; ++i) {
form = abbrevDecl->GetFormByIndexUnchecked(i);
const uint8_t fixed_skip_size = fixed_form_sizes.GetSize(form);
llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
if (fixed_skip_size)
offset += fixed_skip_size;
offset += *fixed_skip_size;
else {
bool form_is_indirect = false;
do {
@ -723,8 +722,8 @@ void DWARFDebugInfoEntry::DumpAttribute(
// results. Any duplicate attributes will have the first instance take
// precedence (this can happen for declaration attributes).
size_t DWARFDebugInfoEntry::GetAttributes(
const DWARFUnit *cu, DWARFFormValue::FixedFormSizes fixed_form_sizes,
DWARFAttributes &attributes, uint32_t curr_depth) const {
const DWARFUnit *cu, DWARFAttributes &attributes,
uint32_t curr_depth) const {
const DWARFAbbreviationDeclaration *abbrevDecl = nullptr;
lldb::offset_t offset = 0;
if (cu)
@ -733,10 +732,6 @@ size_t DWARFDebugInfoEntry::GetAttributes(
if (abbrevDecl) {
const DWARFDataExtractor &debug_info_data = cu->GetData();
if (fixed_form_sizes.Empty())
fixed_form_sizes = DWARFFormValue::GetFixedFormSizesForAddressSize(
cu->GetAddressByteSize());
const uint32_t num_attributes = abbrevDecl->NumAttributes();
for (uint32_t i = 0; i < num_attributes; ++i) {
DWARFFormValue form_value(cu);
@ -769,9 +764,9 @@ size_t DWARFDebugInfoEntry::GetAttributes(
spec_die.GetAttributes(attributes, curr_depth + 1);
}
} else {
const uint8_t fixed_skip_size = fixed_form_sizes.GetSize(form);
llvm::Optional<uint8_t> fixed_skip_size = DWARFFormValue::GetFixedSize(form, cu);
if (fixed_skip_size)
offset += fixed_skip_size;
offset += *fixed_skip_size;
else
DWARFFormValue::SkipValue(form, debug_info_data, &offset, cu);
}
@ -1120,7 +1115,7 @@ bool DWARFDebugInfoEntry::MatchesDWARFDeclContext(
DWARFDIE
DWARFDebugInfoEntry::GetParentDeclContextDIE(DWARFUnit *cu) const {
DWARFAttributes attributes;
GetAttributes(cu, DWARFFormValue::FixedFormSizes(), attributes);
GetAttributes(cu, attributes);
return GetParentDeclContextDIE(cu, attributes);
}
@ -1170,7 +1165,7 @@ DWARFDebugInfoEntry::GetParentDeclContextDIE(
const char *DWARFDebugInfoEntry::GetQualifiedName(DWARFUnit *cu,
std::string &storage) const {
DWARFAttributes attributes;
GetAttributes(cu, DWARFFormValue::FixedFormSizes(), attributes);
GetAttributes(cu, attributes);
return GetQualifiedName(cu, attributes, storage);
}

2
lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
View File

@ -69,7 +69,6 @@ public:
bool FastExtract(const lldb_private::DWARFDataExtractor &debug_info_data,
const DWARFUnit *cu,
const DWARFFormValue::FixedFormSizes &fixed_form_sizes,
lldb::offset_t *offset_ptr);
bool Extract(const DWARFUnit *cu, lldb::offset_t *offset_ptr);
@ -79,7 +78,6 @@ public:
DWARFDebugInfoEntry **block_die);
size_t GetAttributes(const DWARFUnit *cu,
DWARFFormValue::FixedFormSizes fixed_form_sizes,
DWARFAttributes &attrs,
uint32_t curr_depth = 0)
const; // "curr_depth" for internal use only, don't set this yourself!!!

139
lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.cpp
View File

@ -21,92 +21,6 @@ class DWARFUnit;
using namespace lldb_private;
static uint8_t g_form_sizes_addr4[] = {
0, // 0x00 unused
4, // 0x01 DW_FORM_addr
0, // 0x02 unused
0, // 0x03 DW_FORM_block2
0, // 0x04 DW_FORM_block4
2, // 0x05 DW_FORM_data2
4, // 0x06 DW_FORM_data4
8, // 0x07 DW_FORM_data8
0, // 0x08 DW_FORM_string
0, // 0x09 DW_FORM_block
0, // 0x0a DW_FORM_block1
1, // 0x0b DW_FORM_data1
1, // 0x0c DW_FORM_flag
0, // 0x0d DW_FORM_sdata
4, // 0x0e DW_FORM_strp
0, // 0x0f DW_FORM_udata
0, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes for
// DWARF32, 8 bytes for DWARF32 in DWARF 3 and later
1, // 0x11 DW_FORM_ref1
2, // 0x12 DW_FORM_ref2
4, // 0x13 DW_FORM_ref4
8, // 0x14 DW_FORM_ref8
0, // 0x15 DW_FORM_ref_udata
0, // 0x16 DW_FORM_indirect
4, // 0x17 DW_FORM_sec_offset
0, // 0x18 DW_FORM_exprloc
0, // 0x19 DW_FORM_flag_present
0, // 0x1a
0, // 0x1b
0, // 0x1c
0, // 0x1d
0, // 0x1e
0, // 0x1f
8, // 0x20 DW_FORM_ref_sig8
};
static uint8_t g_form_sizes_addr8[] = {
0, // 0x00 unused
8, // 0x01 DW_FORM_addr
0, // 0x02 unused
0, // 0x03 DW_FORM_block2
0, // 0x04 DW_FORM_block4
2, // 0x05 DW_FORM_data2
4, // 0x06 DW_FORM_data4
8, // 0x07 DW_FORM_data8
0, // 0x08 DW_FORM_string
0, // 0x09 DW_FORM_block
0, // 0x0a DW_FORM_block1
1, // 0x0b DW_FORM_data1
1, // 0x0c DW_FORM_flag
0, // 0x0d DW_FORM_sdata
4, // 0x0e DW_FORM_strp
0, // 0x0f DW_FORM_udata
0, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes for
// DWARF32, 8 bytes for DWARF32 in DWARF 3 and later
1, // 0x11 DW_FORM_ref1
2, // 0x12 DW_FORM_ref2
4, // 0x13 DW_FORM_ref4
8, // 0x14 DW_FORM_ref8
0, // 0x15 DW_FORM_ref_udata
0, // 0x16 DW_FORM_indirect
4, // 0x17 DW_FORM_sec_offset
0, // 0x18 DW_FORM_exprloc
0, // 0x19 DW_FORM_flag_present
0, // 0x1a
0, // 0x1b
0, // 0x1c
0, // 0x1d
0, // 0x1e
0, // 0x1f
8, // 0x20 DW_FORM_ref_sig8
};
DWARFFormValue::FixedFormSizes
DWARFFormValue::GetFixedFormSizesForAddressSize(uint8_t addr_size) {
switch (addr_size) {
case 4:
return FixedFormSizes(g_form_sizes_addr4, sizeof(g_form_sizes_addr4));
case 8:
return FixedFormSizes(g_form_sizes_addr8, sizeof(g_form_sizes_addr8));
}
return FixedFormSizes();
}
void DWARFFormValue::Clear() {
m_unit = nullptr;
m_form = 0;
@ -231,6 +145,59 @@ bool DWARFFormValue::ExtractValue(const DWARFDataExtractor &data,
return true;
}
struct FormSize {
uint8_t valid:1, size:7;
};
static FormSize g_form_sizes[] = {
{0,0}, // 0x00 unused
{0,0}, // 0x01 DW_FORM_addr
{0,0}, // 0x02 unused
{0,0}, // 0x03 DW_FORM_block2
{0,0}, // 0x04 DW_FORM_block4
{1,2}, // 0x05 DW_FORM_data2
{1,4}, // 0x06 DW_FORM_data4
{1,8}, // 0x07 DW_FORM_data8
{0,0}, // 0x08 DW_FORM_string
{0,0}, // 0x09 DW_FORM_block
{0,0}, // 0x0a DW_FORM_block1
{1,1}, // 0x0b DW_FORM_data1
{1,1}, // 0x0c DW_FORM_flag
{0,0}, // 0x0d DW_FORM_sdata
{1,4}, // 0x0e DW_FORM_strp
{0,0}, // 0x0f DW_FORM_udata
{0,0}, // 0x10 DW_FORM_ref_addr (addr size for DWARF2 and earlier, 4 bytes for
// DWARF32, 8 bytes for DWARF32 in DWARF 3 and later
{1,1}, // 0x11 DW_FORM_ref1
{1,2}, // 0x12 DW_FORM_ref2
{1,4}, // 0x13 DW_FORM_ref4
{1,8}, // 0x14 DW_FORM_ref8
{0,0}, // 0x15 DW_FORM_ref_udata
{0,0}, // 0x16 DW_FORM_indirect
{1,4}, // 0x17 DW_FORM_sec_offset
{0,0}, // 0x18 DW_FORM_exprloc
{1,0}, // 0x19 DW_FORM_flag_present
{0,0}, // 0x1a
{0,0}, // 0x1b
{0,0}, // 0x1c
{0,0}, // 0x1d
{0,0}, // 0x1e
{0,0}, // 0x1f
{1,8}, // 0x20 DW_FORM_ref_sig8
};
llvm::Optional<uint8_t>
DWARFFormValue::GetFixedSize(dw_form_t form, const DWARFUnit *u) {
if (form <= DW_FORM_ref_sig8 && g_form_sizes[form].valid)
return g_form_sizes[form].size;
if (form == DW_FORM_addr && u)
return u->GetAddressByteSize();
return llvm::None;
}
llvm::Optional<uint8_t> DWARFFormValue::GetFixedSize() const {
return GetFixedSize(m_form, m_unit);
}
bool DWARFFormValue::SkipValue(const DWARFDataExtractor &debug_info_data,
lldb::offset_t *offset_ptr) const {
return DWARFFormValue::SkipValue(m_form, debug_info_data, offset_ptr, m_unit);

23
lldb/source/Plugins/SymbolFile/DWARF/DWARFFormValue.h
View File

@ -11,6 +11,7 @@
#include "DWARFDataExtractor.h"
#include <stddef.h>
#include "llvm/ADT/Optional.h"
class DWARFUnit;
class SymbolFileDWARF;
@ -29,24 +30,6 @@ public:
const uint8_t *data;
} ValueType;
class FixedFormSizes {
public:
FixedFormSizes() : m_fix_sizes(nullptr), m_size(0) {}
FixedFormSizes(const uint8_t *fix_sizes, size_t size)
: m_fix_sizes(fix_sizes), m_size(size) {}
uint8_t GetSize(uint32_t index) const {
return index < m_size ? m_fix_sizes[index] : 0;
}
bool Empty() const { return m_size == 0; }
private:
const uint8_t *m_fix_sizes;
size_t m_size;
};
enum {
eValueTypeInvalid = 0,
eValueTypeUnsigned,
@ -71,6 +54,9 @@ public:
bool ExtractValue(const lldb_private::DWARFDataExtractor &data,
lldb::offset_t *offset_ptr);
const uint8_t *BlockData() const;
static llvm::Optional<uint8_t> GetFixedSize(dw_form_t form,
const DWARFUnit *u);
llvm::Optional<uint8_t> GetFixedSize() const;
DWARFDIE Reference() const;
uint64_t Reference(dw_offset_t offset) const;
bool Boolean() const { return m_value.value.uval != 0; }
@ -88,7 +74,6 @@ public:
lldb::offset_t *offset_ptr, const DWARFUnit *unit);
static bool IsBlockForm(const dw_form_t form);
static bool IsDataForm(const dw_form_t form);
static FixedFormSizes GetFixedFormSizesForAddressSize(uint8_t addr_size);
static int Compare(const DWARFFormValue &a, const DWARFFormValue &b);
void Clear();
static bool FormIsSupported(dw_form_t form);

13
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
View File

@ -60,10 +60,8 @@ void DWARFUnit::ExtractUnitDIEIfNeeded() {
// We are in our compile unit, parse starting at the offset we were told to
// parse
const DWARFDataExtractor &data = GetData();
DWARFFormValue::FixedFormSizes fixed_form_sizes =
DWARFFormValue::GetFixedFormSizesForAddressSize(GetAddressByteSize());
if (offset < GetNextUnitOffset() &&
m_first_die.FastExtract(data, this, fixed_form_sizes, &offset)) {
m_first_die.FastExtract(data, this, &offset)) {
AddUnitDIE(m_first_die);
return;
}
@ -167,10 +165,7 @@ void DWARFUnit::ExtractDIEsRWLocked() {
die_index_stack.reserve(32);
die_index_stack.push_back(0);
bool prev_die_had_children = false;
DWARFFormValue::FixedFormSizes fixed_form_sizes =
DWARFFormValue::GetFixedFormSizesForAddressSize(GetAddressByteSize());
while (offset < next_cu_offset &&
die.FastExtract(data, this, fixed_form_sizes, &offset)) {
while (offset < next_cu_offset && die.FastExtract(data, this, &offset)) {
const bool null_die = die.IsNULL();
if (depth == 0) {
assert(m_die_array.empty() && "Compile unit DIE already added");
@ -415,10 +410,6 @@ TypeSystem *DWARFUnit::GetTypeSystem() {
return nullptr;
}
DWARFFormValue::FixedFormSizes DWARFUnit::GetFixedFormSizes() {
return DWARFFormValue::GetFixedFormSizesForAddressSize(GetAddressByteSize());
}
void DWARFUnit::SetBaseAddress(dw_addr_t base_addr) { m_base_addr = base_addr; }
// Compare function DWARFDebugAranges::Range structures

2
lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
View File

@ -157,8 +157,6 @@ public:
const DWARFDebugAranges &GetFunctionAranges();
DWARFFormValue::FixedFormSizes GetFixedFormSizes();
void SetBaseAddress(dw_addr_t base_addr);
DWARFBaseDIE GetUnitDIEOnly() { return DWARFDIE(this, GetUnitDIEPtrOnly()); }

9
lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
View File

@ -100,20 +100,18 @@ void ManualDWARFIndex::IndexUnit(DWARFUnit &unit, IndexSet &set) {
}
const LanguageType cu_language = unit.GetLanguageType();
DWARFFormValue::FixedFormSizes fixed_form_sizes = unit.GetFixedFormSizes();
IndexUnitImpl(unit, cu_language, fixed_form_sizes, unit.GetOffset(), set);
IndexUnitImpl(unit, cu_language, unit.GetOffset(), set);
SymbolFileDWARFDwo *dwo_symbol_file = unit.GetDwoSymbolFile();
if (dwo_symbol_file && dwo_symbol_file->GetCompileUnit()) {
IndexUnitImpl(*dwo_symbol_file->GetCompileUnit(), cu_language,
fixed_form_sizes, unit.GetOffset(), set);
unit.GetOffset(), set);
}
}
void ManualDWARFIndex::IndexUnitImpl(
DWARFUnit &unit, const LanguageType cu_language,
const DWARFFormValue::FixedFormSizes &fixed_form_sizes,
const dw_offset_t cu_offset, IndexSet &set) {
for (const DWARFDebugInfoEntry &die : unit.dies()) {
const dw_tag_t tag = die.Tag();
@ -150,8 +148,7 @@ void ManualDWARFIndex::IndexUnitImpl(
bool is_global_or_static_variable = false;
DWARFFormValue specification_die_form;
const size_t num_attributes =
die.GetAttributes(&unit, fixed_form_sizes, attributes);
const size_t num_attributes = die.GetAttributes(&unit, attributes);
if (num_attributes > 0) {
for (uint32_t i = 0; i < num_attributes; ++i) {
dw_attr_t attr = attributes.AttributeAtIndex(i);

1
lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
View File

@ -59,7 +59,6 @@ private:
static void
IndexUnitImpl(DWARFUnit &unit, const lldb::LanguageType cu_language,
const DWARFFormValue::FixedFormSizes &fixed_form_sizes,
const dw_offset_t cu_offset, IndexSet &set);
/// Non-null value means we haven't built the index yet.

25
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
View File

@ -3166,13 +3166,11 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
block_length);
} else if (DWARFFormValue::IsDataForm(form_value.Form())) {
// Retrieve the value as a data expression.
DWARFFormValue::FixedFormSizes fixed_form_sizes =
DWARFFormValue::GetFixedFormSizesForAddressSize(
attributes.CompileUnitAtIndex(i)->GetAddressByteSize());
uint32_t data_offset = attributes.DIEOffsetAtIndex(i);
uint32_t data_length =
fixed_form_sizes.GetSize(form_value.Form());
if (data_length == 0) {
if (auto data_length = form_value.GetFixedSize())
location.CopyOpcodeData(module, debug_info_data, data_offset,
*data_length);
else {
const uint8_t *data_pointer = form_value.BlockData();
if (data_pointer) {
form_value.Unsigned();
@ -3181,21 +3179,14 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
// create the variable
const_value = form_value;
}
} else
location.CopyOpcodeData(module, debug_info_data, data_offset,
data_length);
}
} else {
// Retrieve the value as a string expression.
if (form_value.Form() == DW_FORM_strp) {
DWARFFormValue::FixedFormSizes fixed_form_sizes =
DWARFFormValue::GetFixedFormSizesForAddressSize(
attributes.CompileUnitAtIndex(i)
->GetAddressByteSize());
uint32_t data_offset = attributes.DIEOffsetAtIndex(i);
uint32_t data_length =
fixed_form_sizes.GetSize(form_value.Form());
location.CopyOpcodeData(module, debug_info_data, data_offset,
data_length);
if (auto data_length = form_value.GetFixedSize())
location.CopyOpcodeData(module, debug_info_data,
data_offset, *data_length);
} else {
const char *str = form_value.AsCString();
uint32_t string_offset =