This reapplies r207235 with an additional bugfixes caught by the msan

buildbot - do not insert debug intrinsics before phi nodes.

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@207269 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/test/DebugInfo/X86/dbg-value-const-byref.ll b/test/DebugInfo/X86/dbg-value-const-byref.ll
index 2f808786a8..baba0cdb31 100644
--- a/test/DebugInfo/X86/dbg-value-const-byref.ll
+++ b/test/DebugInfo/X86/dbg-value-const-byref.ll
@@ -37,6 +37,10 @@
 ; CHECK: Beginning address offset: [[C2]]
 ; CHECK:    Ending address offset: [[R1:.*]]
 ; CHECK:     Location description: 50 93 04
+;         rdi+0
+; CHECK: Beginning address offset: [[R1]]
+; CHECK:    Ending address offset: [[R2:.*]]
+; CHECK:     Location description: 75 00
 ;
 target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-apple-macosx10.9.0"
@@ -51,6 +55,7 @@ entry:
   %call1 = call i32 (...)* @f1() #3, !dbg !19
   call void @llvm.dbg.value(metadata !{i32 %call1}, i64 0, metadata !10), !dbg !19
   store i32 %call1, i32* %i, align 4, !dbg !19, !tbaa !20
+  call void @llvm.dbg.value(metadata !{i32* %i}, i64 0, metadata !10), !dbg !24
   call void @f2(i32* %i) #3, !dbg !24
   ret i32 0, !dbg !25
 }