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clang-p2996/lldb/source/Plugins/SymbolFile/Breakpad/SymbolFileBreakpad.h
Greg Clayton dd95877958 [lldb] Make only one function that needs to be implemented when searching for types (#74786)
This patch revives the effort to get this Phabricator patch into
upstream:

https://reviews.llvm.org/D137900

This patch was accepted before in Phabricator but I found some
-gsimple-template-names issues that are fixed in this patch.

A fixed up version of the description from the original patch starts
now.

This patch started off trying to fix Module::FindFirstType() as it
sometimes didn't work. The issue was the SymbolFile plug-ins didn't do
any filtering of the matching types they produced, and they only looked
up types using the type basename. This means if you have two types with
the same basename, your type lookup can fail when only looking up a
single type. We would ask the Module::FindFirstType to lookup "Foo::Bar"
and it would ask the symbol file to find only 1 type matching the
basename "Bar", and then we would filter out any matches that didn't
match "Foo::Bar". So if the SymbolFile found "Foo::Bar" first, then it
would work, but if it found "Baz::Bar" first, it would return only that
type and it would be filtered out.

Discovering this issue lead me to think of the patch Alex Langford did a
few months ago that was done for finding functions, where he allowed
SymbolFile objects to make sure something fully matched before parsing
the debug information into an AST type and other LLDB types. So this
patch aimed to allow type lookups to also be much more efficient.

As LLDB has been developed over the years, we added more ways to to type
lookups. These functions have lots of arguments. This patch aims to make
one API that needs to be implemented that serves all previous lookups:

- Find a single type
- Find all types
- Find types in a namespace

This patch introduces a `TypeQuery` class that contains all of the state
needed to perform the lookup which is powerful enough to perform all of
the type searches that used to be in our API. It contain a vector of
CompilerContext objects that can fully or partially specify the lookup
that needs to take place.

If you just want to lookup all types with a matching basename,
regardless of the containing context, you can specify just a single
CompilerContext entry that has a name and a CompilerContextKind mask of
CompilerContextKind::AnyType.

Or you can fully specify the exact context to use when doing lookups
like: CompilerContextKind::Namespace "std"
CompilerContextKind::Class "foo"
CompilerContextKind::Typedef "size_type"

This change expands on the clang modules code that already used a
vector<CompilerContext> items, but it modifies it to work with
expression type lookups which have contexts, or user lookups where users
query for types. The clang modules type lookup is still an option that
can be enabled on the `TypeQuery` objects.

This mirrors the most recent addition of type lookups that took a
vector<CompilerContext> that allowed lookups to happen for the
expression parser in certain places.

Prior to this we had the following APIs in Module:

```
void
Module::FindTypes(ConstString type_name, bool exact_match, size_t max_matches,
                  llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                  TypeList &types);

void
Module::FindTypes(llvm::ArrayRef<CompilerContext> pattern, LanguageSet languages,
                  llvm::DenseSet<lldb_private::SymbolFile *> &searched_symbol_files,
                  TypeMap &types);

void Module::FindTypesInNamespace(ConstString type_name,
                                  const CompilerDeclContext &parent_decl_ctx,
                                  size_t max_matches, TypeList &type_list);
```

The new Module API is much simpler. It gets rid of all three above
functions and replaces them with:

```
void FindTypes(const TypeQuery &query, TypeResults &results);
```
The `TypeQuery` class contains all of the needed settings:

- The vector<CompilerContext> that allow efficient lookups in the symbol
file classes since they can look at basename matches only realize fully
matching types. Before this any basename that matched was fully realized
only to be removed later by code outside of the SymbolFile layer which
could cause many types to be realized when they didn't need to.
- If the lookup is exact or not. If not exact, then the compiler context
must match the bottom most items that match the compiler context,
otherwise it must match exactly
- If the compiler context match is for clang modules or not. Clang
modules matches include a Module compiler context kind that allows types
to be matched only from certain modules and these matches are not needed
when d oing user type lookups.
- An optional list of languages to use to limit the search to only
certain languages

The `TypeResults` object contains all state required to do the lookup
and store the results:
- The max number of matches
- The set of SymbolFile objects that have already been searched
- The matching type list for any matches that are found

The benefits of this approach are:
- Simpler API, and only one API to implement in SymbolFile classes
- Replaces the FindTypesInNamespace that used a CompilerDeclContext as a
way to limit the search, but this only worked if the TypeSystem matched
the current symbol file's type system, so you couldn't use it to lookup
a type in another module
- Fixes a serious bug in our FindFirstType functions where if we were
searching for "foo::bar", and we found a "baz::bar" first, the basename
would match and we would only fetch 1 type using the basename, only to
drop it from the matching list and returning no results
2023-12-12 16:51:49 -08:00

238 lines
8.4 KiB
C++

//===-- SymbolFileBreakpad.h ------------------------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_BREAKPAD_SYMBOLFILEBREAKPAD_H
#define LLDB_SOURCE_PLUGINS_SYMBOLFILE_BREAKPAD_SYMBOLFILEBREAKPAD_H
#include "Plugins/ObjectFile/Breakpad/BreakpadRecords.h"
#include "lldb/Symbol/LineTable.h"
#include "lldb/Symbol/PostfixExpression.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/UnwindPlan.h"
#include "lldb/Utility/FileSpecList.h"
#include <optional>
namespace lldb_private {
namespace breakpad {
class SymbolFileBreakpad : public SymbolFileCommon {
/// LLVM RTTI support.
static char ID;
public:
/// LLVM RTTI support.
/// \{
bool isA(const void *ClassID) const override {
return ClassID == &ID || SymbolFileCommon::isA(ClassID);
}
static bool classof(const SymbolFile *obj) { return obj->isA(&ID); }
/// \}
// Static Functions
static void Initialize();
static void Terminate();
static void DebuggerInitialize(Debugger &debugger) {}
static llvm::StringRef GetPluginNameStatic() { return "breakpad"; }
static llvm::StringRef GetPluginDescriptionStatic() {
return "Breakpad debug symbol file reader.";
}
static SymbolFile *CreateInstance(lldb::ObjectFileSP objfile_sp) {
return new SymbolFileBreakpad(std::move(objfile_sp));
}
// Constructors and Destructors
SymbolFileBreakpad(lldb::ObjectFileSP objfile_sp)
: SymbolFileCommon(std::move(objfile_sp)) {}
~SymbolFileBreakpad() override = default;
uint32_t CalculateAbilities() override;
void InitializeObject() override {}
// Compile Unit function calls
lldb::LanguageType ParseLanguage(CompileUnit &comp_unit) override {
return lldb::eLanguageTypeUnknown;
}
lldb::FunctionSP GetOrCreateFunction(CompileUnit &comp_unit);
size_t ParseFunctions(CompileUnit &comp_unit) override;
bool ParseLineTable(CompileUnit &comp_unit) override;
bool ParseDebugMacros(CompileUnit &comp_unit) override { return false; }
bool ParseSupportFiles(CompileUnit &comp_unit,
FileSpecList &support_files) override;
size_t ParseTypes(CompileUnit &cu) override { return 0; }
bool ParseImportedModules(
const SymbolContext &sc,
std::vector<lldb_private::SourceModule> &imported_modules) override {
return false;
}
size_t ParseBlocksRecursive(Function &func) override;
void FindGlobalVariables(ConstString name,
const CompilerDeclContext &parent_decl_ctx,
uint32_t max_matches,
VariableList &variables) override {}
size_t ParseVariablesForContext(const SymbolContext &sc) override {
return 0;
}
Type *ResolveTypeUID(lldb::user_id_t type_uid) override { return nullptr; }
std::optional<ArrayInfo> GetDynamicArrayInfoForUID(
lldb::user_id_t type_uid,
const lldb_private::ExecutionContext *exe_ctx) override {
return std::nullopt;
}
bool CompleteType(CompilerType &compiler_type) override { return false; }
uint32_t ResolveSymbolContext(const Address &so_addr,
lldb::SymbolContextItem resolve_scope,
SymbolContext &sc) override;
uint32_t ResolveSymbolContext(const SourceLocationSpec &src_location_spec,
lldb::SymbolContextItem resolve_scope,
SymbolContextList &sc_list) override;
void GetTypes(SymbolContextScope *sc_scope, lldb::TypeClass type_mask,
TypeList &type_list) override {}
void FindFunctions(const Module::LookupInfo &lookup_info,
const CompilerDeclContext &parent_decl_ctx,
bool include_inlines, SymbolContextList &sc_list) override;
void FindFunctions(const RegularExpression &regex, bool include_inlines,
SymbolContextList &sc_list) override;
llvm::Expected<lldb::TypeSystemSP>
GetTypeSystemForLanguage(lldb::LanguageType language) override {
return llvm::make_error<llvm::StringError>(
"SymbolFileBreakpad does not support GetTypeSystemForLanguage",
llvm::inconvertibleErrorCode());
}
CompilerDeclContext FindNamespace(ConstString name,
const CompilerDeclContext &parent_decl_ctx,
bool only_root_namespaces) override {
return CompilerDeclContext();
}
void AddSymbols(Symtab &symtab) override;
llvm::Expected<lldb::addr_t> GetParameterStackSize(Symbol &symbol) override;
lldb::UnwindPlanSP
GetUnwindPlan(const Address &address,
const RegisterInfoResolver &resolver) override;
llvm::StringRef GetPluginName() override { return GetPluginNameStatic(); }
uint64_t GetDebugInfoSize() override;
private:
// A class representing a position in the breakpad file. Useful for
// remembering the position so we can go back to it later and parse more data.
// Can be converted to/from a LineIterator, but it has a much smaller memory
// footprint.
struct Bookmark {
uint32_t section;
size_t offset;
friend bool operator<(const Bookmark &lhs, const Bookmark &rhs) {
return std::tie(lhs.section, lhs.offset) <
std::tie(rhs.section, rhs.offset);
}
};
// At iterator class for simplifying algorithms reading data from the breakpad
// file. It iterates over all records (lines) in the sections of a given type.
// It also supports saving a specific position (via the GetBookmark() method)
// and then resuming from it afterwards.
class LineIterator;
// Return an iterator range for all records in the given object file of the
// given type.
llvm::iterator_range<LineIterator> lines(Record::Kind section_type);
// Breakpad files do not contain sufficient information to correctly
// reconstruct compile units. The approach chosen here is to treat each
// function as a compile unit. The compile unit name is the name if the first
// line entry belonging to this function.
// This class is our internal representation of a compile unit. It stores the
// CompileUnit object and a bookmark pointing to the FUNC record of the
// compile unit function. It also lazily construct the list of support files
// and line table entries for the compile unit, when these are needed.
class CompUnitData {
public:
CompUnitData(Bookmark bookmark) : bookmark(bookmark) {}
CompUnitData() = default;
CompUnitData(const CompUnitData &rhs) : bookmark(rhs.bookmark) {}
CompUnitData &operator=(const CompUnitData &rhs) {
bookmark = rhs.bookmark;
support_files.reset();
line_table_up.reset();
return *this;
}
friend bool operator<(const CompUnitData &lhs, const CompUnitData &rhs) {
return lhs.bookmark < rhs.bookmark;
}
Bookmark bookmark;
std::optional<FileSpecList> support_files;
std::unique_ptr<LineTable> line_table_up;
};
uint32_t CalculateNumCompileUnits() override;
lldb::CompUnitSP ParseCompileUnitAtIndex(uint32_t index) override;
lldb::addr_t GetBaseFileAddress();
void ParseFileRecords();
void ParseCUData();
void ParseLineTableAndSupportFiles(CompileUnit &cu, CompUnitData &data);
void ParseUnwindData();
llvm::ArrayRef<uint8_t> SaveAsDWARF(postfix::Node &node);
lldb::UnwindPlanSP ParseCFIUnwindPlan(const Bookmark &bookmark,
const RegisterInfoResolver &resolver);
bool ParseCFIUnwindRow(llvm::StringRef unwind_rules,
const RegisterInfoResolver &resolver,
UnwindPlan::Row &row);
lldb::UnwindPlanSP ParseWinUnwindPlan(const Bookmark &bookmark,
const RegisterInfoResolver &resolver);
void ParseInlineOriginRecords();
using CompUnitMap = RangeDataVector<lldb::addr_t, lldb::addr_t, CompUnitData>;
std::optional<std::vector<FileSpec>> m_files;
std::optional<CompUnitMap> m_cu_data;
std::optional<std::vector<llvm::StringRef>> m_inline_origins;
using UnwindMap = RangeDataVector<lldb::addr_t, lldb::addr_t, Bookmark>;
struct UnwindData {
UnwindMap cfi;
UnwindMap win;
};
std::optional<UnwindData> m_unwind_data;
llvm::BumpPtrAllocator m_allocator;
};
} // namespace breakpad
} // namespace lldb_private
#endif