HackStudio: Reorganize debugger-related files

The debugger's files are now placed under HackStudio/Debugger

DevTools/HackStudio/Debugger/Debugger.cpp

@@ -0,0 +1,179 @@
+/*
+ * Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "Debugger.h"
+
+static Debugger* s_the;
+
+Debugger& Debugger::the()
+{
+    ASSERT(s_the);
+    return *s_the;
+}
+
+void Debugger::initialize(
+    Function<HasControlPassedToUser(const PtraceRegisters&)> on_stop_callback,
+    Function<void()> on_continue_callback,
+    Function<void()> on_exit_callback)
+{
+    s_the = new Debugger(move(on_stop_callback), move(on_continue_callback), move(on_exit_callback));
+}
+
+bool Debugger::is_initialized()
+{
+    return s_the;
+}
+
+Debugger::Debugger(
+    Function<HasControlPassedToUser(const PtraceRegisters&)> on_stop_callback,
+    Function<void()> on_continue_callback,
+    Function<void()> on_exit_callback)
+    : m_on_stopped_callback(move(on_stop_callback))
+    , m_on_continue_callback(move(on_continue_callback))
+    , m_on_exit_callback(move(on_exit_callback))
+{
+    pthread_mutex_init(&m_continue_mutex, nullptr);
+    pthread_cond_init(&m_continue_cond, nullptr);
+}
+
+void Debugger::on_breakpoint_change(const String& file, size_t line, BreakpointChange change_type)
+{
+    auto position = create_source_position(file, line);
+
+    if (change_type == BreakpointChange::Added) {
+        Debugger::the().m_breakpoints.append(position);
+    } else {
+        Debugger::the().m_breakpoints.remove_all_matching([&](DebugInfo::SourcePosition val) { return val == position; });
+    }
+
+    auto session = Debugger::the().session();
+    if (!session)
+        return;
+
+    auto address = session->debug_info().get_instruction_from_source(position.file_path, position.line_number);
+    if (!address.has_value())
+        return;
+
+    if (change_type == BreakpointChange::Added) {
+        bool success = session->insert_breakpoint(reinterpret_cast<void*>(address.value()));
+        ASSERT(success);
+    } else {
+        bool success = session->remove_breakpoint(reinterpret_cast<void*>(address.value()));
+        ASSERT(success);
+    }
+}
+
+DebugInfo::SourcePosition Debugger::create_source_position(const String& file, size_t line)
+{
+    return { String::format("./%s", file.characters()), line + 1 };
+}
+
+int Debugger::start_static()
+{
+    Debugger::the().start();
+    return 0;
+}
+
+void Debugger::start()
+{
+    m_debug_session = DebugSession::exec_and_attach(m_executable_path);
+    ASSERT(!!m_debug_session);
+
+    for (const auto& breakpoint : m_breakpoints) {
+        dbg() << "insertig breakpoint at: " << breakpoint.file_path << ":" << breakpoint.line_number;
+        auto address = m_debug_session->debug_info().get_instruction_from_source(breakpoint.file_path, breakpoint.line_number);
+        if (address.has_value()) {
+            bool success = m_debug_session->insert_breakpoint(reinterpret_cast<void*>(address.value()));
+            ASSERT(success);
+        } else {
+            dbg() << "couldn't insert breakpoint";
+        }
+    }
+
+    debugger_loop();
+}
+
+int Debugger::debugger_loop()
+{
+    bool in_single_step_mode = false;
+    Vector<void*> temporary_breakpoints;
+
+    m_debug_session->run([&](DebugSession::DebugBreakReason reason, Optional<PtraceRegisters> optional_regs) {
+        if (reason == DebugSession::DebugBreakReason::Exited) {
+            dbg() << "Program exited";
+            m_on_exit_callback();
+            return DebugSession::DebugDecision::Detach;
+        }
+        ASSERT(optional_regs.has_value());
+        const PtraceRegisters& regs = optional_regs.value();
+
+        if (in_single_step_mode) {
+            for (auto address : temporary_breakpoints) {
+                m_debug_session->remove_breakpoint(address);
+            }
+            temporary_breakpoints.clear();
+            in_single_step_mode = false;
+        }
+
+        auto control_passed_to_user = m_on_stopped_callback(regs);
+
+        if (control_passed_to_user == HasControlPassedToUser::Yes) {
+            pthread_mutex_lock(&m_continue_mutex);
+            pthread_cond_wait(&m_continue_cond, &m_continue_mutex);
+            pthread_mutex_unlock(&m_continue_mutex);
+
+            m_on_continue_callback();
+        } else {
+            m_continue_type = ContinueType::Continue;
+        }
+
+        if (m_continue_type == ContinueType::Continue) {
+            return DebugSession::DebugDecision::Continue;
+        }
+
+        if (m_continue_type == ContinueType::SourceSingleStep) {
+            // A possible method for source level single stepping is to single step
+            // in assembly level, until the current instruction's source position has changed.
+            // However, since we do not currently generate debug symbols for library code,
+            // we may have to single-step over lots of library code instructions until we get back to our code,
+            // which is very slow.
+            // So the current method is to insert a temporary breakpoint at every known statement in our source code,
+            // continue execution, and remove the temporary breakpoints once we hit the first breakpoint.
+            m_debug_session->debug_info().for_each_source_position([&](DebugInfo::SourcePosition position) {
+                auto address = (void*)position.address_of_first_statement;
+                if ((u32)address != regs.eip && !m_debug_session->breakpoint_exists(address)) {
+                    m_debug_session->insert_breakpoint(address);
+                    temporary_breakpoints.append(address);
+                }
+            });
+            in_single_step_mode = true;
+            return DebugSession::DebugDecision::Continue;
+        }
+        ASSERT_NOT_REACHED();
+    });
+    m_debug_session.clear();
+    return 0;
+}