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[lldb][ELF] Return address class map changes from symbol table parsing methods #91585

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Merged
merged 2 commits into from
May 10, 2024
Merged

[lldb][ELF] Return address class map changes from symbol table parsing methods #91585

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34c5ac8
[lldb][ELF] Return address class map from symbol table parsing methods
DavidSpickett May 9, 2024
d165a1a
Still update the address map for the original object.
DavidSpickett May 9, 2024
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77 changes: 49 additions & 28 deletions lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2060,13 +2060,17 @@ static char FindArmAarch64MappingSymbol(const char *symbol_name) {
#define IS_MICROMIPS(ST_OTHER) (((ST_OTHER)&STO_MIPS_ISA) == STO_MICROMIPS)

// private
unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
SectionList *section_list,
const size_t num_symbols,
const DataExtractor &symtab_data,
const DataExtractor &strtab_data) {
std::pair<unsigned, ObjectFileELF::FileAddressToAddressClassMap>
ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
SectionList *section_list, const size_t num_symbols,
const DataExtractor &symtab_data,
const DataExtractor &strtab_data) {
ELFSymbol symbol;
lldb::offset_t offset = 0;
// The changes these symbols would make to the class map. We will also update
// m_address_class_map but need to tell the caller what changed because the
// caller may be another object file.
FileAddressToAddressClassMap address_class_map;

static ConstString text_section_name(".text");
static ConstString init_section_name(".init");
Expand Down Expand Up @@ -2213,18 +2217,18 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
switch (mapping_symbol) {
case 'a':
// $a[.<any>]* - marks an ARM instruction sequence
m_address_class_map[symbol.st_value] = AddressClass::eCode;
address_class_map[symbol.st_value] = AddressClass::eCode;
break;
case 'b':
case 't':
// $b[.<any>]* - marks a THUMB BL instruction sequence
// $t[.<any>]* - marks a THUMB instruction sequence
m_address_class_map[symbol.st_value] =
address_class_map[symbol.st_value] =
AddressClass::eCodeAlternateISA;
break;
case 'd':
// $d[.<any>]* - marks a data item sequence (e.g. lit pool)
m_address_class_map[symbol.st_value] = AddressClass::eData;
address_class_map[symbol.st_value] = AddressClass::eData;
break;
}
}
Expand All @@ -2238,11 +2242,11 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
switch (mapping_symbol) {
case 'x':
// $x[.<any>]* - marks an A64 instruction sequence
m_address_class_map[symbol.st_value] = AddressClass::eCode;
address_class_map[symbol.st_value] = AddressClass::eCode;
break;
case 'd':
// $d[.<any>]* - marks a data item sequence (e.g. lit pool)
m_address_class_map[symbol.st_value] = AddressClass::eData;
address_class_map[symbol.st_value] = AddressClass::eData;
break;
}
}
Expand All @@ -2260,11 +2264,11 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
// conjunction with symbol.st_value to produce the final
// symbol_value that we store in the symtab.
symbol_value_offset = -1;
m_address_class_map[symbol.st_value ^ 1] =
address_class_map[symbol.st_value ^ 1] =
AddressClass::eCodeAlternateISA;
} else {
// This address is ARM
m_address_class_map[symbol.st_value] = AddressClass::eCode;
address_class_map[symbol.st_value] = AddressClass::eCode;
}
}
}
Expand All @@ -2285,17 +2289,17 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
*/
if (arch.IsMIPS()) {
if (IS_MICROMIPS(symbol.st_other))
m_address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
else if ((symbol.st_value & 1) && (symbol_type == eSymbolTypeCode)) {
symbol.st_value = symbol.st_value & (~1ull);
m_address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
address_class_map[symbol.st_value] = AddressClass::eCodeAlternateISA;
} else {
if (symbol_type == eSymbolTypeCode)
m_address_class_map[symbol.st_value] = AddressClass::eCode;
address_class_map[symbol.st_value] = AddressClass::eCode;
else if (symbol_type == eSymbolTypeData)
m_address_class_map[symbol.st_value] = AddressClass::eData;
address_class_map[symbol.st_value] = AddressClass::eData;
else
m_address_class_map[symbol.st_value] = AddressClass::eUnknown;
address_class_map[symbol.st_value] = AddressClass::eUnknown;
}
}
}
Expand Down Expand Up @@ -2392,24 +2396,33 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
dc_symbol.SetIsWeak(true);
symtab->AddSymbol(dc_symbol);
}
return i;

m_address_class_map.merge(address_class_map);
return {i, address_class_map};
}

unsigned ObjectFileELF::ParseSymbolTable(Symtab *symbol_table,
user_id_t start_id,
lldb_private::Section *symtab) {
std::pair<unsigned, ObjectFileELF::FileAddressToAddressClassMap>
ObjectFileELF::ParseSymbolTable(Symtab *symbol_table, user_id_t start_id,
lldb_private::Section *symtab) {
if (symtab->GetObjectFile() != this) {
// If the symbol table section is owned by a different object file, have it
// do the parsing.
ObjectFileELF *obj_file_elf =
static_cast<ObjectFileELF *>(symtab->GetObjectFile());
return obj_file_elf->ParseSymbolTable(symbol_table, start_id, symtab);
auto [num_symbols, address_class_map] =
obj_file_elf->ParseSymbolTable(symbol_table, start_id, symtab);

// The other object file returned the changes it made to its address
// class map, make the same changes to ours.
m_address_class_map.merge(address_class_map);

return {num_symbols, address_class_map};
}

// Get section list for this object file.
SectionList *section_list = m_sections_up.get();
if (!section_list)
return 0;
return {};

user_id_t symtab_id = symtab->GetID();
const ELFSectionHeaderInfo *symtab_hdr = GetSectionHeaderByIndex(symtab_id);
Expand All @@ -2435,7 +2448,7 @@ unsigned ObjectFileELF::ParseSymbolTable(Symtab *symbol_table,
}
}

return 0;
return {0, {}};
}

size_t ObjectFileELF::ParseDynamicSymbols() {
Expand Down Expand Up @@ -2972,8 +2985,12 @@ void ObjectFileELF::ParseSymtab(Symtab &lldb_symtab) {
// while the reverse is not necessarily true.
Section *symtab =
section_list->FindSectionByType(eSectionTypeELFSymbolTable, true).get();
if (symtab)
symbol_id += ParseSymbolTable(&lldb_symtab, symbol_id, symtab);
if (symtab) {
auto [num_symbols, address_class_map] =
ParseSymbolTable(&lldb_symtab, symbol_id, symtab);
m_address_class_map.merge(address_class_map);
symbol_id += num_symbols;
}

// The symtab section is non-allocable and can be stripped, while the
// .dynsym section which should always be always be there. To support the
Expand All @@ -2986,8 +3003,12 @@ void ObjectFileELF::ParseSymtab(Symtab &lldb_symtab) {
Section *dynsym =
section_list->FindSectionByType(eSectionTypeELFDynamicSymbols, true)
.get();
if (dynsym)
symbol_id += ParseSymbolTable(&lldb_symtab, symbol_id, dynsym);
if (dynsym) {
auto [num_symbols, address_class_map] =
ParseSymbolTable(&lldb_symtab, symbol_id, dynsym);
symbol_id += num_symbols;
m_address_class_map.merge(address_class_map);
}
}

// DT_JMPREL
Expand Down
21 changes: 11 additions & 10 deletions lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.h
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Original file line number Diff line number Diff line change
Expand Up @@ -285,18 +285,19 @@ class ObjectFileELF : public lldb_private::ObjectFile {

/// Populates the symbol table with all non-dynamic linker symbols. This
/// method will parse the symbols only once. Returns the number of symbols
/// parsed.
unsigned ParseSymbolTable(lldb_private::Symtab *symbol_table,
lldb::user_id_t start_id,
lldb_private::Section *symtab);
/// parsed and a map of address types (used by targets like Arm that have
/// an alternative ISA mode like Thumb).
std::pair<unsigned, FileAddressToAddressClassMap>
ParseSymbolTable(lldb_private::Symtab *symbol_table, lldb::user_id_t start_id,
lldb_private::Section *symtab);

/// Helper routine for ParseSymbolTable().
unsigned ParseSymbols(lldb_private::Symtab *symbol_table,
lldb::user_id_t start_id,
lldb_private::SectionList *section_list,
const size_t num_symbols,
const lldb_private::DataExtractor &symtab_data,
const lldb_private::DataExtractor &strtab_data);
std::pair<unsigned, FileAddressToAddressClassMap>
ParseSymbols(lldb_private::Symtab *symbol_table, lldb::user_id_t start_id,
lldb_private::SectionList *section_list,
const size_t num_symbols,
const lldb_private::DataExtractor &symtab_data,
const lldb_private::DataExtractor &strtab_data);

/// Scans the relocation entries and adds a set of artificial symbols to the
/// given symbol table for each PLT slot. Returns the number of symbols
Expand Down