[LanguageRuntime] Move CPPLanguageRuntime into a plugin
Summary: This seems better suited to be in a plugin.
Reviewers: JDevlieghere, clayborg, jingham, compnerd, labath
Subscribers: mgorny, lldb-commits
Differential Revision: https://reviews.llvm.org/D64599
llvm-svn: 365951
diff --git a/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp
new file mode 100644
index 0000000..b392282
--- /dev/null
+++ b/lldb/source/Plugins/LanguageRuntime/CPlusPlus/CPPLanguageRuntime.cpp
@@ -0,0 +1,353 @@
+//===-- CPPLanguageRuntime.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 <string.h>
+
+#include <memory>
+
+#include "CPPLanguageRuntime.h"
+
+#include "llvm/ADT/StringRef.h"
+
+#include "lldb/Symbol/Block.h"
+#include "lldb/Symbol/Variable.h"
+#include "lldb/Symbol/VariableList.h"
+
+#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/UniqueCStringMap.h"
+#include "lldb/Symbol/ClangASTContext.h"
+#include "lldb/Target/ABI.h"
+#include "lldb/Target/ExecutionContext.h"
+#include "lldb/Target/RegisterContext.h"
+#include "lldb/Target/SectionLoadList.h"
+#include "lldb/Target/StackFrame.h"
+#include "lldb/Target/ThreadPlanRunToAddress.h"
+#include "lldb/Target/ThreadPlanStepInRange.h"
+
+using namespace lldb;
+using namespace lldb_private;
+
+static ConstString g_this = ConstString("this");
+
+char CPPLanguageRuntime::ID = 0;
+
+// Destructor
+CPPLanguageRuntime::~CPPLanguageRuntime() {}
+
+CPPLanguageRuntime::CPPLanguageRuntime(Process *process)
+ : LanguageRuntime(process) {}
+
+bool CPPLanguageRuntime::IsWhitelistedRuntimeValue(ConstString name) {
+ return name == g_this;
+}
+
+bool CPPLanguageRuntime::GetObjectDescription(Stream &str,
+ ValueObject &object) {
+ // C++ has no generic way to do this.
+ return false;
+}
+
+bool CPPLanguageRuntime::GetObjectDescription(
+ Stream &str, Value &value, ExecutionContextScope *exe_scope) {
+ // C++ has no generic way to do this.
+ return false;
+}
+
+CPPLanguageRuntime::LibCppStdFunctionCallableInfo
+CPPLanguageRuntime::FindLibCppStdFunctionCallableInfo(
+ lldb::ValueObjectSP &valobj_sp) {
+ LibCppStdFunctionCallableInfo optional_info;
+
+ if (!valobj_sp)
+ return optional_info;
+
+ // Member __f_ has type __base*, the contents of which will hold:
+ // 1) a vtable entry which may hold type information needed to discover the
+ // lambda being called
+ // 2) possibly hold a pointer to the callable object
+ // e.g.
+ //
+ // (lldb) frame var -R f_display
+ // (std::__1::function<void (int)>) f_display = {
+ // __buf_ = {
+ // …
+ // }
+ // __f_ = 0x00007ffeefbffa00
+ // }
+ // (lldb) memory read -fA 0x00007ffeefbffa00
+ // 0x7ffeefbffa00: ... `vtable for std::__1::__function::__func<void (*) ...
+ // 0x7ffeefbffa08: ... `print_num(int) at std_function_cppreference_exam ...
+ //
+ // We will be handling five cases below, std::function is wrapping:
+ //
+ // 1) a lambda we know at compile time. We will obtain the name of the lambda
+ // from the first template pameter from __func's vtable. We will look up
+ // the lambda's operator()() and obtain the line table entry.
+ // 2) a lambda we know at runtime. A pointer to the lambdas __invoke method
+ // will be stored after the vtable. We will obtain the lambdas name from
+ // this entry and lookup operator()() and obtain the line table entry.
+ // 3) a callable object via operator()(). We will obtain the name of the
+ // object from the first template parameter from __func's vtable. We will
+ // look up the objectc operator()() and obtain the line table entry.
+ // 4) a member function. A pointer to the function will stored after the
+ // we will obtain the name from this pointer.
+ // 5) a free function. A pointer to the function will stored after the vtable
+ // we will obtain the name from this pointer.
+ ValueObjectSP member__f_(
+ valobj_sp->GetChildMemberWithName(ConstString("__f_"), true));
+
+ if (member__f_) {
+ ValueObjectSP sub_member__f_(
+ member__f_->GetChildMemberWithName(ConstString("__f_"), true));
+
+ if (sub_member__f_)
+ member__f_ = sub_member__f_;
+ }
+
+ lldb::addr_t member__f_pointer_value = member__f_->GetValueAsUnsigned(0);
+
+ optional_info.member__f_pointer_value = member__f_pointer_value;
+
+ ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
+ Process *process = exe_ctx.GetProcessPtr();
+
+ if (process == nullptr)
+ return optional_info;
+
+ uint32_t address_size = process->GetAddressByteSize();
+ Status status;
+
+ // First item pointed to by __f_ should be the pointer to the vtable for
+ // a __base object.
+ lldb::addr_t vtable_address =
+ process->ReadPointerFromMemory(member__f_pointer_value, status);
+
+ if (status.Fail())
+ return optional_info;
+
+ lldb::addr_t address_after_vtable = member__f_pointer_value + address_size;
+ // As commened above we may not have a function pointer but if we do we will
+ // need it.
+ lldb::addr_t possible_function_address =
+ process->ReadPointerFromMemory(address_after_vtable, status);
+
+ if (status.Fail())
+ return optional_info;
+
+ Target &target = process->GetTarget();
+
+ if (target.GetSectionLoadList().IsEmpty())
+ return optional_info;
+
+ Address vtable_addr_resolved;
+ SymbolContext sc;
+ Symbol *symbol;
+
+ if (!target.GetSectionLoadList().ResolveLoadAddress(vtable_address,
+ vtable_addr_resolved))
+ return optional_info;
+
+ target.GetImages().ResolveSymbolContextForAddress(
+ vtable_addr_resolved, eSymbolContextEverything, sc);
+ symbol = sc.symbol;
+
+ if (symbol == nullptr)
+ return optional_info;
+
+ llvm::StringRef vtable_name(symbol->GetName().GetCString());
+ bool found_expected_start_string =
+ vtable_name.startswith("vtable for std::__1::__function::__func<");
+
+ if (!found_expected_start_string)
+ return optional_info;
+
+ // Given case 1 or 3 we have a vtable name, we are want to extract the first
+ // template parameter
+ //
+ // ... __func<main::$_0, std::__1::allocator<main::$_0> ...
+ // ^^^^^^^^^
+ //
+ // We do this by find the first < and , and extracting in between.
+ //
+ // This covers the case of the lambda known at compile time.
+ size_t first_open_angle_bracket = vtable_name.find('<') + 1;
+ size_t first_comma = vtable_name.find(',');
+
+ llvm::StringRef first_template_parameter =
+ vtable_name.slice(first_open_angle_bracket, first_comma);
+
+ Address function_address_resolved;
+
+ // Setup for cases 2, 4 and 5 we have a pointer to a function after the
+ // vtable. We will use a process of elimination to drop through each case
+ // and obtain the data we need.
+ if (target.GetSectionLoadList().ResolveLoadAddress(
+ possible_function_address, function_address_resolved)) {
+ target.GetImages().ResolveSymbolContextForAddress(
+ function_address_resolved, eSymbolContextEverything, sc);
+ symbol = sc.symbol;
+ }
+
+ auto get_name = [&first_template_parameter, &symbol]() {
+ // Given case 1:
+ //
+ // main::$_0
+ //
+ // we want to append ::operator()()
+ if (first_template_parameter.contains("$_"))
+ return llvm::Regex::escape(first_template_parameter.str()) +
+ R"(::operator\(\)\(.*\))";
+
+ if (symbol != nullptr &&
+ symbol->GetName().GetStringRef().contains("__invoke")) {
+
+ llvm::StringRef symbol_name = symbol->GetName().GetStringRef();
+ size_t pos2 = symbol_name.find_last_of(':');
+
+ // Given case 2:
+ //
+ // main::$_1::__invoke(...)
+ //
+ // We want to slice off __invoke(...) and append operator()()
+ std::string lambda_operator =
+ llvm::Regex::escape(symbol_name.slice(0, pos2 + 1).str()) +
+ R"(operator\(\)\(.*\))";
+
+ return lambda_operator;
+ }
+
+ // Case 3
+ return first_template_parameter.str() + R"(::operator\(\)\(.*\))";
+ ;
+ };
+
+ std::string func_to_match = get_name();
+
+ SymbolContextList scl;
+
+ target.GetImages().FindSymbolsMatchingRegExAndType(
+ RegularExpression{R"(^)" + func_to_match}, eSymbolTypeAny, scl, true);
+
+ // Case 1,2 or 3
+ if (scl.GetSize() >= 1) {
+ SymbolContext sc2 = scl[0];
+
+ AddressRange range;
+ sc2.GetAddressRange(eSymbolContextEverything, 0, false, range);
+
+ Address address = range.GetBaseAddress();
+
+ Address addr;
+ if (target.ResolveLoadAddress(address.GetCallableLoadAddress(&target),
+ addr)) {
+ LineEntry line_entry;
+ addr.CalculateSymbolContextLineEntry(line_entry);
+
+ if (first_template_parameter.contains("$_") ||
+ (symbol != nullptr &&
+ symbol->GetName().GetStringRef().contains("__invoke"))) {
+ // Case 1 and 2
+ optional_info.callable_case = LibCppStdFunctionCallableCase::Lambda;
+ } else {
+ // Case 3
+ optional_info.callable_case =
+ LibCppStdFunctionCallableCase::CallableObject;
+ }
+
+ optional_info.callable_symbol = *symbol;
+ optional_info.callable_line_entry = line_entry;
+ optional_info.callable_address = addr;
+ return optional_info;
+ }
+ }
+
+ // Case 4 or 5
+ if (symbol && !symbol->GetName().GetStringRef().startswith("vtable for")) {
+ optional_info.callable_case =
+ LibCppStdFunctionCallableCase::FreeOrMemberFunction;
+ optional_info.callable_address = function_address_resolved;
+ optional_info.callable_symbol = *symbol;
+
+ return optional_info;
+ }
+
+ return optional_info;
+}
+
+lldb::ThreadPlanSP
+CPPLanguageRuntime::GetStepThroughTrampolinePlan(Thread &thread,
+ bool stop_others) {
+ ThreadPlanSP ret_plan_sp;
+
+ lldb::addr_t curr_pc = thread.GetRegisterContext()->GetPC();
+
+ TargetSP target_sp(thread.CalculateTarget());
+
+ if (target_sp->GetSectionLoadList().IsEmpty())
+ return ret_plan_sp;
+
+ Address pc_addr_resolved;
+ SymbolContext sc;
+ Symbol *symbol;
+
+ if (!target_sp->GetSectionLoadList().ResolveLoadAddress(curr_pc,
+ pc_addr_resolved))
+ return ret_plan_sp;
+
+ target_sp->GetImages().ResolveSymbolContextForAddress(
+ pc_addr_resolved, eSymbolContextEverything, sc);
+ symbol = sc.symbol;
+
+ if (symbol == nullptr)
+ return ret_plan_sp;
+
+ llvm::StringRef function_name(symbol->GetName().GetCString());
+
+ // Handling the case where we are attempting to step into std::function.
+ // The behavior will be that we will attempt to obtain the wrapped
+ // callable via FindLibCppStdFunctionCallableInfo() and if we find it we
+ // will return a ThreadPlanRunToAddress to the callable. Therefore we will
+ // step into the wrapped callable.
+ //
+ bool found_expected_start_string =
+ function_name.startswith("std::__1::function<");
+
+ if (!found_expected_start_string)
+ return ret_plan_sp;
+
+ AddressRange range_of_curr_func;
+ sc.GetAddressRange(eSymbolContextEverything, 0, false, range_of_curr_func);
+
+ StackFrameSP frame = thread.GetStackFrameAtIndex(0);
+
+ if (frame) {
+ ValueObjectSP value_sp = frame->FindVariable(g_this);
+
+ CPPLanguageRuntime::LibCppStdFunctionCallableInfo callable_info =
+ FindLibCppStdFunctionCallableInfo(value_sp);
+
+ if (callable_info.callable_case != LibCppStdFunctionCallableCase::Invalid &&
+ value_sp->GetValueIsValid()) {
+ // We found the std::function wrapped callable and we have its address.
+ // We now create a ThreadPlan to run to the callable.
+ ret_plan_sp = std::make_shared<ThreadPlanRunToAddress>(
+ thread, callable_info.callable_address, stop_others);
+ return ret_plan_sp;
+ } else {
+ // We are in std::function but we could not obtain the callable.
+ // We create a ThreadPlan to keep stepping through using the address range
+ // of the current function.
+ ret_plan_sp = std::make_shared<ThreadPlanStepInRange>(
+ thread, range_of_curr_func, sc, eOnlyThisThread, eLazyBoolYes,
+ eLazyBoolYes);
+ return ret_plan_sp;
+ }
+ }
+
+ return ret_plan_sp;
+}