Read macro info from .debug_macro section and use it for expression evaluation.

Summary:
DWARF 5 proposes a reinvented .debug_macro section. This change follows
that spec.

Currently, only GCC produces the .debug_macro section and hence
the added test is annottated with expectedFailureClang.

Reviewers: spyffe, clayborg, tberghammer

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D15437

llvm-svn: 255729
diff --git a/lldb/source/Symbol/DebugMacros.cpp b/lldb/source/Symbol/DebugMacros.cpp
new file mode 100644
index 0000000..88a28ba
--- /dev/null
+++ b/lldb/source/Symbol/DebugMacros.cpp
@@ -0,0 +1,65 @@
+//===-- DebugMacros.cpp -----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Symbol/DebugMacros.h"
+
+#include "lldb/Symbol/CompileUnit.h"
+
+using namespace lldb_private;
+
+DebugMacroEntry::DebugMacroEntry(EntryType type,
+                                 uint32_t line,
+                                 uint32_t debug_line_file_idx,
+                                 const char *str)
+    : m_type(type),
+      m_line(line),
+      m_debug_line_file_idx(debug_line_file_idx),
+      m_str(str)
+{ }
+
+DebugMacroEntry::DebugMacroEntry(EntryType type,
+                                 const DebugMacrosSP &debug_macros_sp)
+    : m_type(type), m_line(0), m_debug_line_file_idx(0), m_debug_macros_sp(debug_macros_sp)
+{ }
+
+const FileSpec&
+DebugMacroEntry::GetFileSpec(CompileUnit *comp_unit) const
+{
+    return comp_unit->GetSupportFiles().GetFileSpecAtIndex(m_debug_line_file_idx);
+}
+
+DebugMacroEntry
+DebugMacroEntry::CreateDefineEntry(uint32_t line, const char *str)
+{
+    return DebugMacroEntry(DebugMacroEntry::DEFINE, line, 0, str);
+}
+
+DebugMacroEntry
+DebugMacroEntry::CreateUndefEntry(uint32_t line, const char *str)
+{
+    return DebugMacroEntry(DebugMacroEntry::UNDEF, line, 0, str);
+}
+
+DebugMacroEntry
+DebugMacroEntry::CreateStartFileEntry(uint32_t line, uint32_t debug_line_file_idx)
+{
+    return DebugMacroEntry(DebugMacroEntry::START_FILE, line, debug_line_file_idx, nullptr);
+}
+
+DebugMacroEntry
+DebugMacroEntry::CreateEndFileEntry()
+{
+    return DebugMacroEntry(DebugMacroEntry::END_FILE, 0, 0, nullptr);
+}
+
+DebugMacroEntry
+DebugMacroEntry::CreateIndirectEntry(const DebugMacrosSP &debug_macros_sp)
+{
+    return DebugMacroEntry(DebugMacroEntry::INDIRECT, debug_macros_sp);
+}