This reapplies r207130 with an additional testcase+and a missing check for

AllocaInst that was missing in one location.
Debug info for optimized code: Support variables that are on the stack and
described by DBG_VALUEs during their lifetime.

Previously, when a variable was at a FrameIndex for any part of its
lifetime, this would shadow all other DBG_VALUEs and only a single
fbreg location would be emitted, which in fact is only valid for a small
range and not the entire lexical scope of the variable. The included
dbg-value-const-byref testcase demonstrates this.

This patch fixes this by
Local
- emitting dbg.value intrinsics for allocas that are passed by reference
- dropping all dbg.declares (they are now fully lowered to dbg.values)
SelectionDAG
- renamed constructors for SDDbgValue for better readability.
- fix UserValue::match() to handle indirect values correctly
- not inserting an MMI table entries for dbg.values that describe allocas.
- lowering dbg.values that describe allocas into *indirect* DBG_VALUEs.
CodeGenPrepare
- leaving dbg.values for an alloca were they are (see comment)
Other
- regenerated/updated instcombine.ll testcase and included source

rdar://problem/16679879
http://reviews.llvm.org/D3374

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207165 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 5 deletions

diff --git a/include/llvm/CodeGen/SelectionDAG.h b/include/llvm/CodeGen/SelectionDAG.h
index b827c5147a..a13d104d23 100644
--- a/include/llvm/CodeGen/SelectionDAG.h
+++ b/include/llvm/CodeGen/SelectionDAG.h
@@ -928,12 +928,15 @@ public:
 
   /// getDbgValue - Creates a SDDbgValue node.
   ///
-  SDDbgValue *getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R, uint64_t Off,
-                          DebugLoc DL, unsigned O);
-  SDDbgValue *getDbgValue(MDNode *MDPtr, const Value *C, uint64_t Off,
-                          DebugLoc DL, unsigned O);
-  SDDbgValue *getDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
+  SDDbgValue *getDbgValue(MDNode *MDPtr, SDNode *N, unsigned R,
+			  bool IsIndirect, uint64_t Off,
                           DebugLoc DL, unsigned O);
+  /// Constant.
+  SDDbgValue *getConstantDbgValue(MDNode *MDPtr, const Value *C, uint64_t Off,
+				  DebugLoc DL, unsigned O);
+  /// Frame index.
+  SDDbgValue *getFrameIndexDbgValue(MDNode *MDPtr, unsigned FI, uint64_t Off,
+				    DebugLoc DL, unsigned O);
 
   /// RemoveDeadNode - Remove the specified node from the system. If any of its
   /// operands then becomes dead, remove them as well. Inform UpdateListener