HackStudio: Implement "Step Out" debugging action

The "Step Out" action continues execution until the current function
returns.

Also, LibDebug/StackFrameUtils was introduced to eliminate the
duplication of stack frame inspection logic between the "Step Out"
action and the BacktraceModel.

3 files changed, 83 insertions, 0 deletions

diff --git a/Libraries/LibDebug/CMakeLists.txt b/Libraries/LibDebug/CMakeLists.txt
index ad2f1bfb15..f4c4277436 100644
--- a/Libraries/LibDebug/CMakeLists.txt
+++ b/Libraries/LibDebug/CMakeLists.txt
@@ -7,6 +7,7 @@ set(SOURCES
     Dwarf/DwarfInfo.cpp
     Dwarf/Expression.cpp
     Dwarf/LineProgram.cpp
+    StackFrameUtils.cpp
 )
 
 serenity_lib(LibDebug debug)
diff --git a/Libraries/LibDebug/StackFrameUtils.cpp b/Libraries/LibDebug/StackFrameUtils.cpp
new file mode 100644
index 0000000000..e85fce6754
--- /dev/null
+++ b/Libraries/LibDebug/StackFrameUtils.cpp
@@ -0,0 +1,40 @@
+/*
+ * 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 "StackFrameUtils.h"
+
+namespace StackFrameUtils {
+Optional<StackFrameInfo> get_info(const DebugSession& session, FlatPtr current_ebp)
+{
+    auto return_address = session.peek(reinterpret_cast<u32*>(current_ebp + sizeof(FlatPtr)));
+    auto next_ebp = session.peek(reinterpret_cast<u32*>(current_ebp));
+    if (!return_address.has_value() || !next_ebp.has_value())
+        return {};
+
+    StackFrameInfo info = { return_address.value(), next_ebp.value() };
+    return info;
+}
+}
diff --git a/Libraries/LibDebug/StackFrameUtils.h b/Libraries/LibDebug/StackFrameUtils.h
new file mode 100644
index 0000000000..9948ee04a7
--- /dev/null
+++ b/Libraries/LibDebug/StackFrameUtils.h
@@ -0,0 +1,42 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <AK/Optional.h>
+#include <AK/Types.h>
+
+#include "LibDebug/DebugSession.h"
+
+namespace StackFrameUtils {
+struct StackFrameInfo {
+    FlatPtr return_address;
+    FlatPtr next_ebp;
+};
+
+Optional<StackFrameInfo> get_info(const DebugSession&, FlatPtr current_ebp);
+
+}