Files
clang-p2996/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
Michael Buch 28d14904c0 [lldb][SymbolFileDWARF] Share GetDIEToType between SymbolFiles of a SymbolFileDWARFDebugMap (#120569)
The problem here manifests as follows:
1. We are stopped in main.o, so the first `ParseTypeFromDWARF` on
`FooImpl<char>` gets called on `main.o`'s SymbolFile. This adds a
mapping from *declaration die* -> `TypeSP` into `main.o`'s
`GetDIEToType` map.
2. We then `CompleteType(FooImpl<char>)`. Depending on the order of
entries in the debug-map, this might call `CompleteType` on `lib.o`'s
SymbolFile. In which case, `GetDIEToType().lookup(decl_die)` will return
a `nullptr`. This is already a bit iffy because some of the surrounding
code assumes we don't call `CompleteTypeFromDWARF` with a `nullptr`
`Type*`. E.g., `CompleteEnumType` blindly dereferences it (though enums
will never encounter this because their definition is fetched in
ParseEnum, unlike for structures).
3. While in `CompleteTypeFromDWARF`, we call `ParseTypeFromDWARF` again.
This will parse the member function `FooImpl::Create` and its return
type which is a typedef to `FooImpl*`. But now we're inside `lib.o`'s
SymbolFile, so we call it on the definition DIE. In step (2) we just
inserted a `nullptr` into `GetDIEToType` for the definition DIE, so we
trivially return a `nullptr` from `ParseTypeFromDWARF`. Instead of
reporting back this parse failure to the user LLDB trucks on and marks
`FooImpl::Ref` to be `void*`.

This test-case will trigger an assert in `TypeSystemClang::VerifyDecl`
even if we just `frame var` (but only in debug-builds). In release
builds where this function is a no-op, we'll create an incorrect Clang
AST node for the `Ref` typedef.

The proposed fix here is to share the `GetDIEToType` map between
SymbolFiles if a debug-map exists.

**Alternatives considered**
* Check the `GetDIEToType` map of the `SymbolFile` that the declaration
DIE belongs to. The assumption here being that if we called
`ParseTypeFromDWARF` on a declaration, the `GetDIEToType` map that the
result was inserted into was the one on that DIE's SymbolFile. This was
the first version of this patch, but that felt like a weaker version
sharing the map. It complicates the code in `CompleteType` and is less
consistent with the other bookkeeping structures we already share
between SymbolFiles
* Return from `SymbolFileDWARF::CompleteType` if there is no type in the
current `GetDIEToType`. Then `SymbolFileDWARFDebugMap::CompleteType`
could continue to the next `SymbolFile` which does own the type. But
that didn't quite work because we remove the
`GetForwardCompilerTypeToDie` entry in `SymbolFile::CompleteType`, which
`SymbolFileDWARFDebugMap::CompleteType` relies upon for iterating
2024-12-23 11:51:28 +00:00

182 lines
6.5 KiB
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//===-- SymbolFileDWARFDwo.cpp --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "SymbolFileDWARFDwo.h"
#include "lldb/Core/Section.h"
#include "lldb/Expression/DWARFExpression.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Utility/LLDBAssert.h"
#include "llvm/Support/Casting.h"
#include "DWARFCompileUnit.h"
#include "DWARFDebugInfo.h"
#include "DWARFUnit.h"
#include <optional>
using namespace lldb;
using namespace lldb_private;
using namespace lldb_private::plugin::dwarf;
char SymbolFileDWARFDwo::ID;
SymbolFileDWARFDwo::SymbolFileDWARFDwo(SymbolFileDWARF &base_symbol_file,
ObjectFileSP objfile, uint32_t id)
: SymbolFileDWARF(objfile, objfile->GetSectionList(
/*update_module_section_list*/ false)),
m_base_symbol_file(base_symbol_file) {
SetFileIndex(id);
// Parsing of the dwarf unit index is not thread-safe, so we need to prime it
// to enable subsequent concurrent lookups.
m_context.GetAsLLVM().getCUIndex();
}
DWARFCompileUnit *SymbolFileDWARFDwo::GetDWOCompileUnitForHash(uint64_t hash) {
if (const llvm::DWARFUnitIndex &index = m_context.GetAsLLVM().getCUIndex()) {
if (const llvm::DWARFUnitIndex::Entry *entry = index.getFromHash(hash)) {
if (auto *unit_contrib = entry->getContribution())
return llvm::dyn_cast_or_null<DWARFCompileUnit>(
DebugInfo().GetUnitAtOffset(DIERef::Section::DebugInfo,
unit_contrib->getOffset()));
}
return nullptr;
}
DWARFCompileUnit *cu = FindSingleCompileUnit();
if (!cu)
return nullptr;
std::optional<uint64_t> dwo_id = cu->GetDWOId();
if (!dwo_id || hash != *dwo_id)
return nullptr;
return cu;
}
DWARFCompileUnit *SymbolFileDWARFDwo::FindSingleCompileUnit() {
DWARFDebugInfo &debug_info = DebugInfo();
// Right now we only support dwo files with one compile unit. If we don't have
// type units, we can just check for the unit count.
if (!debug_info.ContainsTypeUnits() && debug_info.GetNumUnits() == 1)
return llvm::cast<DWARFCompileUnit>(debug_info.GetUnitAtIndex(0));
// Otherwise, we have to run through all units, and find the compile unit that
// way.
DWARFCompileUnit *cu = nullptr;
for (size_t i = 0; i < debug_info.GetNumUnits(); ++i) {
if (auto *candidate =
llvm::dyn_cast<DWARFCompileUnit>(debug_info.GetUnitAtIndex(i))) {
if (cu)
return nullptr; // More that one CU found.
cu = candidate;
}
}
return cu;
}
lldb::offset_t SymbolFileDWARFDwo::GetVendorDWARFOpcodeSize(
const lldb_private::DataExtractor &data, const lldb::offset_t data_offset,
const uint8_t op) const {
return GetBaseSymbolFile().GetVendorDWARFOpcodeSize(data, data_offset, op);
}
uint64_t SymbolFileDWARFDwo::GetDebugInfoSize(bool load_all_debug_info) {
// Directly get debug info from current dwo object file's section list
// instead of asking SymbolFileCommon::GetDebugInfo() which parses from
// owning module which is wrong.
SectionList *section_list =
m_objfile_sp->GetSectionList(/*update_module_section_list=*/false);
if (section_list)
return section_list->GetDebugInfoSize();
return 0;
}
bool SymbolFileDWARFDwo::ParseVendorDWARFOpcode(
uint8_t op, const lldb_private::DataExtractor &opcodes,
lldb::offset_t &offset, std::vector<lldb_private::Value> &stack) const {
return GetBaseSymbolFile().ParseVendorDWARFOpcode(op, opcodes, offset, stack);
}
llvm::DenseMap<const DWARFDebugInfoEntry *, Type *> &
SymbolFileDWARFDwo::GetDIEToType() {
return GetBaseSymbolFile().GetDIEToType();
}
SymbolFileDWARF::DIEToVariableSP &SymbolFileDWARFDwo::GetDIEToVariable() {
return GetBaseSymbolFile().GetDIEToVariable();
}
llvm::DenseMap<lldb::opaque_compiler_type_t, DIERef> &
SymbolFileDWARFDwo::GetForwardDeclCompilerTypeToDIE() {
return GetBaseSymbolFile().GetForwardDeclCompilerTypeToDIE();
}
void SymbolFileDWARFDwo::GetObjCMethods(
lldb_private::ConstString class_name,
llvm::function_ref<bool(DWARFDIE die)> callback) {
GetBaseSymbolFile().GetObjCMethods(class_name, callback);
}
UniqueDWARFASTTypeMap &SymbolFileDWARFDwo::GetUniqueDWARFASTTypeMap() {
return GetBaseSymbolFile().GetUniqueDWARFASTTypeMap();
}
DWARFDIE SymbolFileDWARFDwo::FindDefinitionDIE(const DWARFDIE &die) {
return GetBaseSymbolFile().FindDefinitionDIE(die);
}
lldb::TypeSP SymbolFileDWARFDwo::FindCompleteObjCDefinitionTypeForDIE(
const DWARFDIE &die, lldb_private::ConstString type_name,
bool must_be_implementation) {
return GetBaseSymbolFile().FindCompleteObjCDefinitionTypeForDIE(
die, type_name, must_be_implementation);
}
llvm::Expected<lldb::TypeSystemSP>
SymbolFileDWARFDwo::GetTypeSystemForLanguage(LanguageType language) {
return GetBaseSymbolFile().GetTypeSystemForLanguage(language);
}
DWARFDIE
SymbolFileDWARFDwo::GetDIE(const DIERef &die_ref) {
if (die_ref.file_index() == GetFileIndex())
return DebugInfo().GetDIE(die_ref.section(), die_ref.die_offset());
return GetBaseSymbolFile().GetDIE(die_ref);
}
void SymbolFileDWARFDwo::FindGlobalVariables(
ConstString name, const CompilerDeclContext &parent_decl_ctx,
uint32_t max_matches, VariableList &variables) {
GetBaseSymbolFile().FindGlobalVariables(name, parent_decl_ctx, max_matches,
variables);
}
bool SymbolFileDWARFDwo::GetDebugInfoIndexWasLoadedFromCache() const {
return GetBaseSymbolFile().GetDebugInfoIndexWasLoadedFromCache();
}
void SymbolFileDWARFDwo::SetDebugInfoIndexWasLoadedFromCache() {
GetBaseSymbolFile().SetDebugInfoIndexWasLoadedFromCache();
}
bool SymbolFileDWARFDwo::GetDebugInfoIndexWasSavedToCache() const {
return GetBaseSymbolFile().GetDebugInfoIndexWasSavedToCache();
}
void SymbolFileDWARFDwo::SetDebugInfoIndexWasSavedToCache() {
GetBaseSymbolFile().SetDebugInfoIndexWasSavedToCache();
}
bool SymbolFileDWARFDwo::GetDebugInfoHadFrameVariableErrors() const {
return GetBaseSymbolFile().GetDebugInfoHadFrameVariableErrors();
}
void SymbolFileDWARFDwo::SetDebugInfoHadFrameVariableErrors() {
return GetBaseSymbolFile().SetDebugInfoHadFrameVariableErrors();
}
SymbolFileDWARF *
SymbolFileDWARFDwo::GetDIERefSymbolFile(const DIERef &die_ref) {
return GetBaseSymbolFile().GetDIERefSymbolFile(die_ref);
}