[SelectionDAG] Support multiple dangling debug info for one value

Summary:
When building the selection DAG we sometimes need to postpone
the handling of a dbg.value until the value it should refer to
is created. This is done by using the DanglingDebugInfoMap.
In the past this map has been limited to hold one dangling
dbg.value per value. This patch removes that restriction.

Reviewers: aprantl, rnk, probinson, vsk

Reviewed By: aprantl

Subscribers: Ka-Ka, llvm-commits, JDevlieghere

Tags: #debug-info

Differential Revision: https://reviews.llvm.org/D44610

llvm-svn: 328084

1 files changed, 9 insertions, 15 deletions

diff --git a/llvm/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll b/llvm/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll
index a8ef9565718..0a75f74a5b3 100644
--- a/llvm/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll
+++ b/llvm/test/DebugInfo/X86/sdag-dangling-dbgvalue.ll
@@ -50,8 +50,8 @@
 ; CHECK:  ![[BAR3:.*]] = !DILocalVariable(name: "foo3"
 ; CHECK:  ![[FOO4:.*]] = !DILocalVariable(name: "foo4"
 ; CHECK:  ![[BAR4:.*]] = !DILocalVariable(name: "bar4"
-; CHECK:  ![[FOO5:.*]] = !DILocalVariable(name: "bar5"
-; CHECK:  ![[BAR5:.*]] = !DILocalVariable(name: "foo5"
+; CHECK:  ![[BAR5:.*]] = !DILocalVariable(name: "bar5"
+; CHECK:  ![[FOO5:.*]] = !DILocalVariable(name: "foo5"
 
 
 source_filename = "sdag-dangling-dbgvalue.c"
@@ -74,13 +74,11 @@ entry1:
   ret i32 ptrtoint (%struct.SS* @S to i32), !dbg !25
 }
 
-; Verify that the def comes before the debug-use for bar2.
-; TODO: Currently dbg.value for foo2 is dropped. Seems to be a bug. The
-;       SelectionDAGBuilder should support several dangling dbg.value for the
-;       same value.
+; Verify that the def comes before the debug-use for foo2 and bar2.
 define i32 @test2() local_unnamed_addr #0 !dbg !26 {
 ; CHECK-LABEL: bb.0.entry2
 ; CHECK-NEXT:    [[REG2:%[0-9]+]]:gr64 =
+; CHECK-NEXT:    DBG_VALUE debug-use [[REG2]], debug-use $noreg, ![[FOO2]], !DIExpression()
 ; CHECK-NEXT:    DBG_VALUE debug-use [[REG2]], debug-use $noreg, ![[BAR2]], !DIExpression()
 entry2:
   call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !28, metadata !DIExpression()), !dbg !30
@@ -88,13 +86,11 @@ entry2:
   ret i32 add (i32 ptrtoint (%struct.SS* @S to i32), i32 ptrtoint (%struct.SS* @S to i32)), !dbg !32
 }
 
-; Verify that the def comes before the debug-use for foo3.
-; TODO: Currently dbg.value for bar3 is dropped. Seems to be a bug. The
-;       SelectionDAGBuilder should support several dangling dbg.value for the
-;       same value.
+; Verify that the def comes before the debug-use for foo3 and bar3.
 define i32 @test3() local_unnamed_addr #0 !dbg !33 {
 ; CHECK-LABEL: bb.0.entry3
 ; CHECK-NEXT:    [[REG3:%[0-9]+]]:gr64 =
+; CHECK-NEXT:    DBG_VALUE debug-use [[REG3]], debug-use $noreg, ![[BAR3]], !DIExpression()
 ; CHECK-NEXT:    DBG_VALUE debug-use [[REG3]], debug-use $noreg, ![[FOO3]], !DIExpression()
 entry3:
   call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !36, metadata !DIExpression()), !dbg !38
@@ -118,15 +114,13 @@ entry4:
 }
 
 ; Verify that we do not get a DBG_VALUE that maps foo5 to @S here.
-; TODO: At the moment we do not get any DBG_VALUE at all here. If
-;       SelectionDAGBuilder should support several dangling dbg.value for the
-;       same value it would be possible to at least get a DBG_VALUE for
-;       bar5.
 ; TODO: foo5 is set to null, and it is not really used. Just like in test1 it
 ;       can be discussed if there should be a DBG_VALUE for foo5 here.
 define i32 @test5() local_unnamed_addr #0 !dbg !47 {
 ; CHECK-LABEL: bb.0.entry5:
-; CHECK-NOT:     DBG_VALUE
+; CHECK-NEXT:    [[REG5:%[0-9]+]]:gr64 =
+; CHECK-NEXT:    DBG_VALUE debug-use [[REG5]], debug-use $noreg, ![[BAR5]], !DIExpression()
+; CHECK-NOT:     DBG_VALUE debug-use [[REG5]], debug-use $noreg, ![[FOO5]], !DIExpression()
 ; CHECK:         RET
 entry5:
   call void @llvm.dbg.value(metadata %struct.SS* @S, metadata !49, metadata !DIExpression()), !dbg !51