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, 2 insertions, 2 deletions

diff --git a/llvm/test/DebugInfo/X86/inline-member-function.ll b/llvm/test/DebugInfo/X86/inline-member-function.ll
index c1a367e7e0f..c0b4ab28fb8 100644
--- a/llvm/test/DebugInfo/X86/inline-member-function.ll
+++ b/llvm/test/DebugInfo/X86/inline-member-function.ll
@@ -88,8 +88,8 @@ attributes #1 = { nounwind readnone }
 !21 = !{i32 1, !"Debug Info Version", i32 3}
 !22 = !{!"clang version 3.5.0 "}
 !23 = !MDLocation(line: 8, scope: !13)
-!24 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "this", arg: 1, flags: DIFlagArtificial | DIFlagObjectPointer, scope: !17, type: !25)
+!24 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "this", arg: 1, flags: DIFlagArtificial | DIFlagObjectPointer, scope: !17, type: !25, inlinedAt: !23)
 !25 = !MDDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: !"_ZTS3foo")
 !26 = !MDLocation(line: 0, scope: !17, inlinedAt: !23)
-!27 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "x", line: 2, arg: 2, scope: !17, file: !14, type: !9)
+!27 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "x", line: 2, arg: 2, scope: !17, file: !14, type: !9, inlinedAt: !23)
 !28 = !MDLocation(line: 2, scope: !17, inlinedAt: !23)