lldb/source/Plugins/InstrumentationRuntime/ThreadSanitizer/ThreadSanitizerRuntime.cpp

//===-- ThreadSanitizerRuntime.cpp ------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "ThreadSanitizerRuntime.h"

#include "lldb/Breakpoint/StoppointCallbackContext.h"
#include "lldb/Core/Debugger.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ModuleList.h"
#include "lldb/Core/RegularExpression.h"
#include "lldb/Core/PluginInterface.h"
#include "lldb/Core/PluginManager.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/StreamFile.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Expression/UserExpression.h"
#include "lldb/Interpreter/CommandReturnObject.h"
#include "lldb/Symbol/Symbol.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Target/InstrumentationRuntimeStopInfo.h"
#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/StopInfo.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"
#include "Plugins/Process/Utility/HistoryThread.h"

using namespace lldb;
using namespace lldb_private;

lldb::InstrumentationRuntimeSP
ThreadSanitizerRuntime::CreateInstance (const lldb::ProcessSP &process_sp)
{
    return InstrumentationRuntimeSP(new ThreadSanitizerRuntime(process_sp));
}

void
ThreadSanitizerRuntime::Initialize()
{
    PluginManager::RegisterPlugin (GetPluginNameStatic(),
                                   "ThreadSanitizer instrumentation runtime plugin.",
                                   CreateInstance,
                                   GetTypeStatic);
}

void
ThreadSanitizerRuntime::Terminate()
{
    PluginManager::UnregisterPlugin (CreateInstance);
}

lldb_private::ConstString
ThreadSanitizerRuntime::GetPluginNameStatic()
{
    return ConstString("ThreadSanitizer");
}

lldb::InstrumentationRuntimeType
ThreadSanitizerRuntime::GetTypeStatic()
{
    return eInstrumentationRuntimeTypeThreadSanitizer;
}

ThreadSanitizerRuntime::ThreadSanitizerRuntime(const ProcessSP &process_sp) :
m_is_active(false),
m_runtime_module_wp(),
m_process_wp(),
m_breakpoint_id(0)
{
    if (process_sp)
        m_process_wp = process_sp;
}

ThreadSanitizerRuntime::~ThreadSanitizerRuntime()
{
    Deactivate();
}

static bool
ModuleContainsTSanRuntime(ModuleSP module_sp)
{
    static ConstString g_tsan_get_current_report("__tsan_get_current_report");
    const Symbol* symbol = module_sp->FindFirstSymbolWithNameAndType(g_tsan_get_current_report, lldb::eSymbolTypeAny);
    return symbol != nullptr;
}

void
ThreadSanitizerRuntime::ModulesDidLoad(lldb_private::ModuleList &module_list)
{
    if (IsActive())
        return;
    
    if (GetRuntimeModuleSP()) {
        Activate();
        return;
    }
    
    module_list.ForEach ([this](const lldb::ModuleSP module_sp) -> bool
    {
        const FileSpec & file_spec = module_sp->GetFileSpec();
        if (! file_spec)
            return true; // Keep iterating through modules
        
        llvm::StringRef module_basename(file_spec.GetFilename().GetStringRef());
        if (module_sp->IsExecutable() || module_basename.startswith("libclang_rt.tsan_"))
        {
            if (ModuleContainsTSanRuntime(module_sp))
            {
                m_runtime_module_wp = module_sp;
                Activate();
                return false; // Stop iterating
            }
        }

        return true; // Keep iterating through modules
    });
}

bool
ThreadSanitizerRuntime::IsActive()
{
    return m_is_active;
}

#define RETRIEVE_REPORT_DATA_FUNCTION_TIMEOUT_USEC 2*1000*1000

const char *
thread_sanitizer_retrieve_report_data_prefix = R"(
extern "C"
{
    void *__tsan_get_current_report();
    int __tsan_get_report_data(void *report, const char **description, int *count,
                               int *stack_count, int *mop_count, int *loc_count,
                               int *mutex_count, int *thread_count,
                               int *unique_tid_count, void **sleep_trace,
                               unsigned long trace_size);
    int __tsan_get_report_stack(void *report, unsigned long idx, void **trace,
                                unsigned long trace_size);
    int __tsan_get_report_mop(void *report, unsigned long idx, int *tid, void **addr,
                              int *size, int *write, int *atomic, void **trace,
                              unsigned long trace_size);
    int __tsan_get_report_loc(void *report, unsigned long idx, const char **type,
                              void **addr, unsigned long *start, unsigned long *size, int *tid,
                              int *fd, int *suppressable, void **trace,
                              unsigned long trace_size);
    int __tsan_get_report_mutex(void *report, unsigned long idx, unsigned long *mutex_id, void **addr,
                                int *destroyed, void **trace, unsigned long trace_size);
    int __tsan_get_report_thread(void *report, unsigned long idx, int *tid, unsigned long *pid,
                                 int *running, const char **name, int *parent_tid,
                                 void **trace, unsigned long trace_size);
    int __tsan_get_report_unique_tid(void *report, unsigned long idx, int *tid);
}

const int REPORT_TRACE_SIZE = 128;
const int REPORT_ARRAY_SIZE = 4;

struct data {
    void *report;
    const char *description;
    int report_count;
    
    void *sleep_trace[REPORT_TRACE_SIZE];
    
    int stack_count;
    struct {
        int idx;
        void *trace[REPORT_TRACE_SIZE];
    } stacks[REPORT_ARRAY_SIZE];
    
    int mop_count;
    struct {
        int idx;
        int tid;
        int size;
        int write;
        int atomic;
        void *addr;
        void *trace[REPORT_TRACE_SIZE];
    } mops[REPORT_ARRAY_SIZE];
    
    int loc_count;
    struct {
        int idx;
        const char *type;
        void *addr;
        unsigned long start;
        unsigned long size;
        int tid;
        int fd;
        int suppressable;
        void *trace[REPORT_TRACE_SIZE];
    } locs[REPORT_ARRAY_SIZE];
    
    int mutex_count;
    struct {
        int idx;
        unsigned long mutex_id;
        void *addr;
        int destroyed;
        void *trace[REPORT_TRACE_SIZE];
    } mutexes[REPORT_ARRAY_SIZE];
    
    int thread_count;
    struct {
        int idx;
        int tid;
        unsigned long pid;
        int running;
        const char *name;
        int parent_tid;
        void *trace[REPORT_TRACE_SIZE];
    } threads[REPORT_ARRAY_SIZE];
    
    int unique_tid_count;
    struct {
        int idx;
        int tid;
    } unique_tids[REPORT_ARRAY_SIZE];
};
)";

const char *
thread_sanitizer_retrieve_report_data_command = R"(
data t = {0};

t.report = __tsan_get_current_report();
__tsan_get_report_data(t.report, &t.description, &t.report_count, &t.stack_count, &t.mop_count, &t.loc_count, &t.mutex_count, &t.thread_count, &t.unique_tid_count, t.sleep_trace, REPORT_TRACE_SIZE);

if (t.stack_count > REPORT_ARRAY_SIZE) t.stack_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.stack_count; i++) {
    t.stacks[i].idx = i;
    __tsan_get_report_stack(t.report, i, t.stacks[i].trace, REPORT_TRACE_SIZE);
}

if (t.mop_count > REPORT_ARRAY_SIZE) t.mop_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.mop_count; i++) {
    t.mops[i].idx = i;
    __tsan_get_report_mop(t.report, i, &t.mops[i].tid, &t.mops[i].addr, &t.mops[i].size, &t.mops[i].write, &t.mops[i].atomic, t.mops[i].trace, REPORT_TRACE_SIZE);
}

if (t.loc_count > REPORT_ARRAY_SIZE) t.loc_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.loc_count; i++) {
    t.locs[i].idx = i;
    __tsan_get_report_loc(t.report, i, &t.locs[i].type, &t.locs[i].addr, &t.locs[i].start, &t.locs[i].size, &t.locs[i].tid, &t.locs[i].fd, &t.locs[i].suppressable, t.locs[i].trace, REPORT_TRACE_SIZE);
}

if (t.mutex_count > REPORT_ARRAY_SIZE) t.mutex_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.mutex_count; i++) {
    t.mutexes[i].idx = i;
    __tsan_get_report_mutex(t.report, i, &t.mutexes[i].mutex_id, &t.mutexes[i].addr, &t.mutexes[i].destroyed, t.mutexes[i].trace, REPORT_TRACE_SIZE);
}

if (t.thread_count > REPORT_ARRAY_SIZE) t.thread_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.thread_count; i++) {
    t.threads[i].idx = i;
    __tsan_get_report_thread(t.report, i, &t.threads[i].tid, &t.threads[i].pid, &t.threads[i].running, &t.threads[i].name, &t.threads[i].parent_tid, t.threads[i].trace, REPORT_TRACE_SIZE);
}

if (t.unique_tid_count > REPORT_ARRAY_SIZE) t.unique_tid_count = REPORT_ARRAY_SIZE;
for (int i = 0; i < t.unique_tid_count; i++) {
    t.unique_tids[i].idx = i;
    __tsan_get_report_unique_tid(t.report, i, &t.unique_tids[i].tid);
}

t;
)";

static StructuredData::Array *
CreateStackTrace(ValueObjectSP o, std::string trace_item_name = ".trace") {
    StructuredData::Array *trace = new StructuredData::Array();
    ValueObjectSP trace_value_object = o->GetValueForExpressionPath(trace_item_name.c_str());
    for (int j = 0; j < 8; j++) {
        addr_t trace_addr = trace_value_object->GetChildAtIndex(j, true)->GetValueAsUnsigned(0);
        if (trace_addr == 0)
            break;
        trace->AddItem(StructuredData::ObjectSP(new StructuredData::Integer(trace_addr)));
    }
    return trace;
}

static StructuredData::Array *
ConvertToStructuredArray(ValueObjectSP return_value_sp, std::string items_name, std::string count_name, std::function <void(ValueObjectSP o, StructuredData::Dictionary *dict)> const &callback)
{
    StructuredData::Array *array = new StructuredData::Array();
    unsigned int count = return_value_sp->GetValueForExpressionPath(count_name.c_str())->GetValueAsUnsigned(0);
    ValueObjectSP objects = return_value_sp->GetValueForExpressionPath(items_name.c_str());
    for (unsigned int i = 0; i < count; i++) {
        ValueObjectSP o = objects->GetChildAtIndex(i, true);
        StructuredData::Dictionary *dict = new StructuredData::Dictionary();
        
        callback(o, dict);
        
        array->AddItem(StructuredData::ObjectSP(dict));
    }
    return array;
}

static std::string
RetrieveString(ValueObjectSP return_value_sp, ProcessSP process_sp, std::string expression_path)
{
    addr_t ptr = return_value_sp->GetValueForExpressionPath(expression_path.c_str())->GetValueAsUnsigned(0);
    std::string str;
    Error error;
    process_sp->ReadCStringFromMemory(ptr, str, error);
    return str;
}

StructuredData::ObjectSP
ThreadSanitizerRuntime::RetrieveReportData(ExecutionContextRef exe_ctx_ref)
{
    ProcessSP process_sp = GetProcessSP();
    if (!process_sp)
        return StructuredData::ObjectSP();
    
    ThreadSP thread_sp = exe_ctx_ref.GetThreadSP();
    StackFrameSP frame_sp = thread_sp->GetSelectedFrame();
    
    if (!frame_sp)
        return StructuredData::ObjectSP();
    
    EvaluateExpressionOptions options;
    options.SetUnwindOnError(true);
    options.SetTryAllThreads(true);
    options.SetStopOthers(true);
    options.SetIgnoreBreakpoints(true);
    options.SetTimeoutUsec(RETRIEVE_REPORT_DATA_FUNCTION_TIMEOUT_USEC);
    options.SetPrefix(thread_sanitizer_retrieve_report_data_prefix);
    
    ValueObjectSP main_value;
    ExecutionContext exe_ctx;
    Error eval_error;
    frame_sp->CalculateExecutionContext(exe_ctx);
    ExpressionResults result = UserExpression::Evaluate (exe_ctx,
                              options,
                              thread_sanitizer_retrieve_report_data_command,
                              "",
                              main_value,
                              eval_error);
    if (result != eExpressionCompleted) {
        process_sp->GetTarget().GetDebugger().GetAsyncOutputStream()->Printf("Warning: Cannot evaluate ThreadSanitizer expression:\n%s\n", eval_error.AsCString());
        return StructuredData::ObjectSP();
    }
    
    StructuredData::Dictionary *dict = new StructuredData::Dictionary();
    dict->AddStringItem("instrumentation_class", "ThreadSanitizer");
    dict->AddStringItem("issue_type", RetrieveString(main_value, process_sp, ".description"));
    dict->AddIntegerItem("report_count", main_value->GetValueForExpressionPath(".report_count")->GetValueAsUnsigned(0));
    dict->AddItem("sleep_trace", StructuredData::ObjectSP(CreateStackTrace(main_value, ".sleep_trace")));
    
    StructuredData::Array *stacks = ConvertToStructuredArray(main_value, ".stacks", ".stack_count", [] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddItem("trace", StructuredData::ObjectSP(CreateStackTrace(o)));
    });
    dict->AddItem("stacks", StructuredData::ObjectSP(stacks));
    
    StructuredData::Array *mops = ConvertToStructuredArray(main_value, ".mops", ".mop_count", [] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("thread_id", o->GetValueForExpressionPath(".tid")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("size", o->GetValueForExpressionPath(".size")->GetValueAsUnsigned(0));
        dict->AddBooleanItem("is_write", o->GetValueForExpressionPath(".write")->GetValueAsUnsigned(0));
        dict->AddBooleanItem("is_atomic", o->GetValueForExpressionPath(".atomic")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("address", o->GetValueForExpressionPath(".addr")->GetValueAsUnsigned(0));
        dict->AddItem("trace", StructuredData::ObjectSP(CreateStackTrace(o)));
    });
    dict->AddItem("mops", StructuredData::ObjectSP(mops));
    
    StructuredData::Array *locs = ConvertToStructuredArray(main_value, ".locs", ".loc_count", [process_sp] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddStringItem("type", RetrieveString(o, process_sp, ".type"));
        dict->AddIntegerItem("address", o->GetValueForExpressionPath(".addr")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("start", o->GetValueForExpressionPath(".start")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("size", o->GetValueForExpressionPath(".size")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("thread_id", o->GetValueForExpressionPath(".tid")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("file_descriptor", o->GetValueForExpressionPath(".fd")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("suppressable", o->GetValueForExpressionPath(".suppressable")->GetValueAsUnsigned(0));
        dict->AddItem("trace", StructuredData::ObjectSP(CreateStackTrace(o)));
    });
    dict->AddItem("locs", StructuredData::ObjectSP(locs));
    
    StructuredData::Array *mutexes = ConvertToStructuredArray(main_value, ".mutexes", ".mutex_count", [] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("mutex_id", o->GetValueForExpressionPath(".mutex_id")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("address", o->GetValueForExpressionPath(".addr")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("destroyed", o->GetValueForExpressionPath(".destroyed")->GetValueAsUnsigned(0));
        dict->AddItem("trace", StructuredData::ObjectSP(CreateStackTrace(o)));
    });
    dict->AddItem("mutexes", StructuredData::ObjectSP(mutexes));
    
    StructuredData::Array *threads = ConvertToStructuredArray(main_value, ".threads", ".thread_count", [process_sp] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("thread_id", o->GetValueForExpressionPath(".tid")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("process_id", o->GetValueForExpressionPath(".pid")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("running", o->GetValueForExpressionPath(".running")->GetValueAsUnsigned(0));
        dict->AddStringItem("name", RetrieveString(o, process_sp, ".name"));
        dict->AddIntegerItem("parent_thread_id", o->GetValueForExpressionPath(".parent_tid")->GetValueAsUnsigned(0));
        dict->AddItem("trace", StructuredData::ObjectSP(CreateStackTrace(o)));
    });
    dict->AddItem("threads", StructuredData::ObjectSP(threads));
    
    StructuredData::Array *unique_tids = ConvertToStructuredArray(main_value, ".unique_tids", ".unique_tid_count", [] (ValueObjectSP o, StructuredData::Dictionary *dict) {
        dict->AddIntegerItem("index", o->GetValueForExpressionPath(".idx")->GetValueAsUnsigned(0));
        dict->AddIntegerItem("tid", o->GetValueForExpressionPath(".tid")->GetValueAsUnsigned(0));
    });
    dict->AddItem("unique_tids", StructuredData::ObjectSP(unique_tids));
    
    return StructuredData::ObjectSP(dict);
}

std::string
ThreadSanitizerRuntime::FormatDescription(StructuredData::ObjectSP report)
{
    std::string description = report->GetAsDictionary()->GetValueForKey("issue_type")->GetAsString()->GetValue();
    
    if (description == "data-race") {
        return "Data race";
    } else if (description == "data-race-vptr") {
        return "Data race on C++ virtual pointer";
    } else if (description == "heap-use-after-free") {
        return "Use of deallocated memory";
    } else if (description == "heap-use-after-free-vptr") {
        return "Use of deallocated C++ virtual pointer";
    } else if (description == "thread-leak") {
        return "Thread leak";
    } else if (description == "locked-mutex-destroy") {
        return "Destruction of a locked mutex";
    } else if (description == "mutex-double-lock") {
        return "Double lock of a mutex";
    } else if (description == "mutex-invalid-access") {
        return "Use of an invalid mutex (e.g. uninitialized or destroyed)";
    } else if (description == "mutex-bad-unlock") {
        return "Unlock of an unlocked mutex (or by a wrong thread)";
    } else if (description == "mutex-bad-read-lock") {
        return "Read lock of a write locked mutex";
    } else if (description == "mutex-bad-read-unlock") {
        return "Read unlock of a write locked mutex";
    } else if (description == "signal-unsafe-call") {
        return "Signal-unsafe call inside a signal handler";
    } else if (description == "errno-in-signal-handler") {
        return "Overwrite of errno in a signal handler";
    } else if (description == "lock-order-inversion") {
        return "Lock order inversion (potential deadlock)";
    }
    
    // for unknown report codes just show the code
    return description;
}

static std::string
Sprintf(const char *format, ...)
{
    StreamString s;
    va_list args;
    va_start (args, format);
    s.PrintfVarArg(format, args);
    va_end (args);
    return s.GetString();
}

static std::string
GetSymbolNameFromAddress(ProcessSP process_sp, addr_t addr)
{
    lldb_private::Address so_addr;
    if (! process_sp->GetTarget().GetSectionLoadList().ResolveLoadAddress(addr, so_addr))
        return "";
    
    lldb_private::Symbol *symbol = so_addr.CalculateSymbolContextSymbol();
    if (! symbol)
        return "";
    
    std::string sym_name = symbol->GetName().GetCString();
    return sym_name;
}

addr_t
ThreadSanitizerRuntime::GetFirstNonInternalFramePc(StructuredData::ObjectSP trace)
{
    ProcessSP process_sp = GetProcessSP();
    ModuleSP runtime_module_sp = GetRuntimeModuleSP();
    
    addr_t result = 0;
    trace->GetAsArray()->ForEach([process_sp, runtime_module_sp, &result] (StructuredData::Object *o) -> bool {
        addr_t addr = o->GetIntegerValue();
        lldb_private::Address so_addr;
        if (! process_sp->GetTarget().GetSectionLoadList().ResolveLoadAddress(addr, so_addr))
            return true;
        
        if (so_addr.GetModule() == runtime_module_sp)
            return true;
        
        result = addr;
        return false;
    });
    
    return result;
}

std::string
ThreadSanitizerRuntime::GenerateSummary(StructuredData::ObjectSP report)
{
    ProcessSP process_sp = GetProcessSP();
    
    std::string summary = report->GetAsDictionary()->GetValueForKey("description")->GetAsString()->GetValue();
    addr_t pc = 0;
    if (report->GetAsDictionary()->GetValueForKey("mops")->GetAsArray()->GetSize() > 0)
        pc = GetFirstNonInternalFramePc(report->GetAsDictionary()->GetValueForKey("mops")->GetAsArray()->GetItemAtIndex(0)->GetAsDictionary()->GetValueForKey("trace"));

    if (report->GetAsDictionary()->GetValueForKey("stacks")->GetAsArray()->GetSize() > 0)
        pc = GetFirstNonInternalFramePc(report->GetAsDictionary()->GetValueForKey("stacks")->GetAsArray()->GetItemAtIndex(0)->GetAsDictionary()->GetValueForKey("trace"));

    if (pc != 0) {
        summary = summary + " in " + GetSymbolNameFromAddress(process_sp, pc);
    }
    
    if (report->GetAsDictionary()->GetValueForKey("locs")->GetAsArray()->GetSize() > 0) {
        StructuredData::ObjectSP loc = report->GetAsDictionary()->GetValueForKey("locs")->GetAsArray()->GetItemAtIndex(0);
        addr_t addr = loc->GetAsDictionary()->GetValueForKey("address")->GetAsInteger()->GetValue();
        if (addr == 0)
            addr = loc->GetAsDictionary()->GetValueForKey("start")->GetAsInteger()->GetValue();
        
        if (addr != 0) {
            summary = summary + " at " + Sprintf("0x%llx", addr);
        } else {
            int fd = loc->GetAsDictionary()->GetValueForKey("file_descriptor")->GetAsInteger()->GetValue();
            if (fd != 0) {
                summary = summary + " on file descriptor " + Sprintf("%d", fd);
            }
        }
    }
    
    return summary;
}

addr_t
ThreadSanitizerRuntime::GetMainRacyAddress(StructuredData::ObjectSP report)
{
    addr_t result = (addr_t)-1;
    
    report->GetObjectForDotSeparatedPath("mops")->GetAsArray()->ForEach([&result] (StructuredData::Object *o) -> bool {
        addr_t addr = o->GetObjectForDotSeparatedPath("address")->GetIntegerValue();
        if (addr < result) result = addr;
        return true;
    });

    return (result == (addr_t)-1) ? 0 : result;
}

std::string
ThreadSanitizerRuntime::GetLocationDescription(StructuredData::ObjectSP report)
{
    std::string result = "";
    
    ProcessSP process_sp = GetProcessSP();
    
    if (report->GetAsDictionary()->GetValueForKey("locs")->GetAsArray()->GetSize() > 0) {
        StructuredData::ObjectSP loc = report->GetAsDictionary()->GetValueForKey("locs")->GetAsArray()->GetItemAtIndex(0);
        std::string type = loc->GetAsDictionary()->GetValueForKey("type")->GetStringValue();
        if (type == "global") {
            addr_t addr = loc->GetAsDictionary()->GetValueForKey("address")->GetAsInteger()->GetValue();
            std::string global_name = GetSymbolNameFromAddress(process_sp, addr);
            result = Sprintf("Location is a global '%s'", global_name.c_str());
        } else if (type == "heap") {
            addr_t addr = loc->GetAsDictionary()->GetValueForKey("start")->GetAsInteger()->GetValue();
            long size = loc->GetAsDictionary()->GetValueForKey("size")->GetAsInteger()->GetValue();
            result = Sprintf("Location is a %ld-byte heap object at 0x%llx", size, addr);
        } else if (type == "stack") {
            int tid = loc->GetAsDictionary()->GetValueForKey("thread_id")->GetAsInteger()->GetValue();
            result = Sprintf("Location is stack of thread %d", tid);
        } else if (type == "tls") {
            int tid = loc->GetAsDictionary()->GetValueForKey("thread_id")->GetAsInteger()->GetValue();
            result = Sprintf("Location is TLS of thread %d", tid);
        } else if (type == "fd") {
            int fd = loc->GetAsDictionary()->GetValueForKey("file_descriptor")->GetAsInteger()->GetValue();
            result = Sprintf("Location is file descriptor %d", fd);
        }
    }
    
    return result;
}

bool
ThreadSanitizerRuntime::NotifyBreakpointHit(void *baton, StoppointCallbackContext *context, user_id_t break_id, user_id_t break_loc_id)
{
    assert (baton && "null baton");
    if (!baton)
        return false;
    
    ThreadSanitizerRuntime *const instance = static_cast<ThreadSanitizerRuntime*>(baton);
    
    StructuredData::ObjectSP report = instance->RetrieveReportData(context->exe_ctx_ref);
    std::string stop_reason_description;
    if (report) {
        std::string issue_description = instance->FormatDescription(report);
        report->GetAsDictionary()->AddStringItem("description", issue_description);
        stop_reason_description = issue_description + " detected";
        report->GetAsDictionary()->AddStringItem("stop_description", stop_reason_description);
        std::string summary = instance->GenerateSummary(report);
        report->GetAsDictionary()->AddStringItem("summary", summary);
        addr_t main_address = instance->GetMainRacyAddress(report);
        report->GetAsDictionary()->AddIntegerItem("memory_address", main_address);
        std::string location_description = instance->GetLocationDescription(report);
        report->GetAsDictionary()->AddStringItem("location_description", location_description);
    }
    
    ProcessSP process_sp = instance->GetProcessSP();
    // Make sure this is the right process
    if (process_sp && process_sp == context->exe_ctx_ref.GetProcessSP())
    {
        ThreadSP thread_sp = context->exe_ctx_ref.GetThreadSP();
        if (thread_sp)
            thread_sp->SetStopInfo(InstrumentationRuntimeStopInfo::CreateStopReasonWithInstrumentationData(*thread_sp, stop_reason_description.c_str(), report));
        
        StreamFileSP stream_sp (process_sp->GetTarget().GetDebugger().GetOutputFile());
        if (stream_sp)
        {
            stream_sp->Printf ("ThreadSanitizer report breakpoint hit. Use 'thread info -s' to get extended information about the report.\n");
        }
        return true;    // Return true to stop the target
    }
    else
        return false;   // Let target run
}

void
ThreadSanitizerRuntime::Activate()
{
    if (m_is_active)
        return;
    
    ProcessSP process_sp = GetProcessSP();
    if (!process_sp)
        return;
    
    ConstString symbol_name ("__tsan_on_report");
    const Symbol *symbol = GetRuntimeModuleSP()->FindFirstSymbolWithNameAndType (symbol_name, eSymbolTypeCode);
    
    if (symbol == NULL)
        return;
    
    if (!symbol->ValueIsAddress() || !symbol->GetAddressRef().IsValid())
        return;
    
    Target &target = process_sp->GetTarget();
    addr_t symbol_address = symbol->GetAddressRef().GetOpcodeLoadAddress(&target);
    
    if (symbol_address == LLDB_INVALID_ADDRESS)
        return;
    
    bool internal = true;
    bool hardware = false;
    Breakpoint *breakpoint = process_sp->GetTarget().CreateBreakpoint(symbol_address, internal, hardware).get();
    breakpoint->SetCallback (ThreadSanitizerRuntime::NotifyBreakpointHit, this, true);
    breakpoint->SetBreakpointKind ("thread-sanitizer-report");
    m_breakpoint_id = breakpoint->GetID();
    
    StreamFileSP stream_sp (process_sp->GetTarget().GetDebugger().GetOutputFile());
    if (stream_sp)
    {
        stream_sp->Printf ("ThreadSanitizer debugger support is active.\n");
    }
    
    m_is_active = true;
}

void
ThreadSanitizerRuntime::Deactivate()
{
    if (m_breakpoint_id != LLDB_INVALID_BREAK_ID)
    {
        ProcessSP process_sp = GetProcessSP();
        if (process_sp)
        {
            process_sp->GetTarget().RemoveBreakpointByID(m_breakpoint_id);
            m_breakpoint_id = LLDB_INVALID_BREAK_ID;
        }
    }
    m_is_active = false;
}

static std::string
GenerateThreadName(std::string path, StructuredData::Object *o) {
    std::string result = "additional information";
    
    if (path == "mops") {
        int size = o->GetObjectForDotSeparatedPath("size")->GetIntegerValue();
        int thread_id = o->GetObjectForDotSeparatedPath("thread_id")->GetIntegerValue();
        bool is_write = o->GetObjectForDotSeparatedPath("is_write")->GetBooleanValue();
        bool is_atomic = o->GetObjectForDotSeparatedPath("is_atomic")->GetBooleanValue();
        addr_t addr = o->GetObjectForDotSeparatedPath("address")->GetIntegerValue();
        
        result = Sprintf("%s%s of size %d at 0x%llx by thread %d", is_atomic ? "atomic " : "", is_write ? "write" : "read", size, addr, thread_id);
    }
    
    if (path == "threads") {
        int thread_id = o->GetObjectForDotSeparatedPath("thread_id")->GetIntegerValue();
        int parent_thread_id = o->GetObjectForDotSeparatedPath("parent_thread_id")->GetIntegerValue();
        
        result = Sprintf("thread %d created by thread %d at", thread_id, parent_thread_id);
    }
    
    if (path == "locs") {
        std::string type = o->GetAsDictionary()->GetValueForKey("type")->GetStringValue();
        int thread_id = o->GetObjectForDotSeparatedPath("thread_id")->GetIntegerValue();
        int fd = o->GetObjectForDotSeparatedPath("file_descriptor")->GetIntegerValue();
        if (type == "heap") {
            result = Sprintf("Heap block allocated by thread %d at", thread_id);
        } else if (type == "fd") {
            result = Sprintf("File descriptor %d created by thread %t at", fd, thread_id);
        }
    }
    
    if (path == "mutexes") {
        int mutex_id = o->GetObjectForDotSeparatedPath("mutex_id")->GetIntegerValue();
        
        result = Sprintf("mutex M%d created at", mutex_id);
    }
    
    if (path == "stacks") {
        result = "happened at";
    }
    
    result[0] = toupper(result[0]);
    
    return result;
}

static void
AddThreadsForPath(std::string path, ThreadCollectionSP threads, ProcessSP process_sp, StructuredData::ObjectSP info)
{
    info->GetObjectForDotSeparatedPath(path)->GetAsArray()->ForEach([process_sp, threads, path] (StructuredData::Object *o) -> bool {
        std::vector<lldb::addr_t> pcs;
        o->GetObjectForDotSeparatedPath("trace")->GetAsArray()->ForEach([&pcs] (StructuredData::Object *pc) -> bool {
            pcs.push_back(pc->GetAsInteger()->GetValue());
            return true;
        });
        
        if (pcs.size() == 0)
            return true;
        
        StructuredData::ObjectSP thread_id_obj = o->GetObjectForDotSeparatedPath("thread_id");
        tid_t tid = thread_id_obj ? thread_id_obj->GetIntegerValue() : 0;
        
        uint32_t stop_id = 0;
        bool stop_id_is_valid = false;
        HistoryThread *history_thread = new HistoryThread(*process_sp, tid, pcs, stop_id, stop_id_is_valid);
        ThreadSP new_thread_sp(history_thread);
        new_thread_sp->SetName(GenerateThreadName(path, o).c_str());
        
        // Save this in the Process' ExtendedThreadList so a strong pointer retains the object
        process_sp->GetExtendedThreadList().AddThread(new_thread_sp);
        threads->AddThread(new_thread_sp);
        
        return true;
    });
}

lldb::ThreadCollectionSP
ThreadSanitizerRuntime::GetBacktracesFromExtendedStopInfo(StructuredData::ObjectSP info)
{
    ThreadCollectionSP threads;
    threads.reset(new ThreadCollection());

    if (info->GetObjectForDotSeparatedPath("instrumentation_class")->GetStringValue() != "ThreadSanitizer")
        return threads;
    
    ProcessSP process_sp = GetProcessSP();
    
    AddThreadsForPath("stacks", threads, process_sp, info);
    AddThreadsForPath("mops", threads, process_sp, info);
    AddThreadsForPath("locs", threads, process_sp, info);
    AddThreadsForPath("mutexes", threads, process_sp, info);
    AddThreadsForPath("threads", threads, process_sp, info);
    
    return threads;
}