Verifier: Check that inlined-at locations agree

Check that the `MDLocalVariable::getInlinedAt()` in a debug info
intrinsic's variable always matches the `MDLocation::getInlinedAt()` of
its `!dbg` attachment.

The goal here is to get rid of `MDLocalVariable::getInlinedAt()`
entirely (PR22778), since it's expensive and unnecessary, but I'll let
this verifier check bake for a while (a week maybe?) first.  I've
updated the testcases that had the wrong value for `inlinedAt:`.

This checks that things are sane in the IR, but currently things go out
of whack in a few places in the backend.  I'll follow shortly with
assertions in the backend (with code fixes).

If you have out-of-tree testcases that just started failing, here's how
I updated these ones:

 1. The verifier check gives you the basic block, function, instruction,
    and relevant metadata arguments (metadata numbering doesn't
    necessarily match the source file, unfortunately).
 2. Look at the `@llvm.dbg.*()` instruction, and compare the
    `inlinedAt:` fields of the variable argument (second `metadata`
    argument) and the `!dbg` attachment.
 3. Figure out based on the variable `scope:` chain and the functions in
    the file whether the variable has been inlined (and into what), so
    you can determine which `inlinedAt:` is actually correct.  In all of
    the in-tree testcases, the `!MDLocation()` was correct and the
    `!MDLocalVariable()` was wrong, but YMMV.
 4. Duplicate the metadata that you're going to change, and add/drop the
    `inlinedAt:` field from one of them.  Be careful that the other
    references to the same metadata node point at the correct one.

llvm-svn: 234021

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll b/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
index c5be61f78f8..223daadfd77 100644
--- a/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
+++ b/llvm/test/DebugInfo/X86/InlinedFnLocalVar.ll
@@ -15,8 +15,8 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon
 define i32 @bar() nounwind ssp {
 entry:
   %0 = load i32, i32* @i, align 4, !dbg !17            ; <i32> [#uses=2]
-  tail call void @llvm.dbg.value(metadata i32 %0, i64 0, metadata !9, metadata !MDExpression()), !dbg !19
-  tail call void @llvm.dbg.declare(metadata !29, metadata !10, metadata !MDExpression()), !dbg !21
+  tail call void @llvm.dbg.value(metadata i32 %0, i64 0, metadata !109, metadata !MDExpression()), !dbg !19
+  tail call void @llvm.dbg.declare(metadata !29, metadata !110, metadata !MDExpression()), !dbg !21
   %1 = mul nsw i32 %0, %0, !dbg !22               ; <i32> [#uses=2]
   store i32 %1, i32* @i, align 4, !dbg !17
   ret i32 %1, !dbg !23
@@ -36,6 +36,10 @@ entry:
 !8 = !{!5}
 !9 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "j", line: 9, arg: 0, scope: !0, file: !1, type: !5)
 !10 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "xyz", line: 10, scope: !11, file: !1, type: !12)
+
+!109 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "j", line: 9, arg: 0, scope: !0, file: !1, type: !5, inlinedAt: !17)
+!110 = !MDLocalVariable(tag: DW_TAG_auto_variable, name: "xyz", line: 10, scope: !11, file: !1, type: !12, inlinedAt: !17)
+
 !11 = distinct !MDLexicalBlock(line: 9, column: 0, file: !1, scope: !0)
 !12 = !MDCompositeType(tag: DW_TAG_structure_type, name: "X", line: 10, size: 64, align: 32, file: !27, scope: !0, elements: !13)
 !13 = !{!14, !15}