Introduce DebugScope which gets embedded into the machine instructions' DebugLoc.
DebugScope refers to a debug region, function or block.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72191 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/DebugLoc.cpp b/lib/CodeGen/DebugLoc.cpp
new file mode 100644
index 0000000..bc1a5b1
--- /dev/null
+++ b/lib/CodeGen/DebugLoc.cpp
@@ -0,0 +1,38 @@
+//===-- DebugLoc.cpp ------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation for DebugScopeTracker.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/DebugLoc.h"
+#include "llvm/CodeGen/MachineFunction.h"
+using namespace llvm;
+
+/// EnterDebugScope - Start a new debug scope. ScopeGV can be a DISubprogram
+/// or a DIBlock.
+void DebugScopeTracker::EnterDebugScope(GlobalVariable *ScopeGV,
+                                        MachineFunction &MF) {
+  assert(ScopeGV && "GlobalVariable for scope is null!");
+  CurScope = MF.CreateDebugScope(ScopeGV, CurScope);
+}
+
+/// ExitDebugScope - "Pop" a DISubprogram or a DIBlock.
+void DebugScopeTracker::ExitDebugScope(GlobalVariable *ScopeGV,
+                                       MachineFunction &MF) {
+  assert(ScopeGV && "GlobalVariable for scope is null!");
+  assert(!CurScope.isInvalid() && "Mismatched region.end ?");
+  // We may have skipped a region.end because it was in an unreachable block.
+  // Go up the scope chain until we reach the scope that ScopeGV points to.
+  DebugScopeInfo DSI;
+  do {
+    DSI =  MF.getDebugScopeInfo(CurScope);
+    CurScope = DSI.Parent;
+  } while (!DSI.Parent.isInvalid() && DSI.GV != ScopeGV);
+}