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, 4 insertions, 1 deletions

diff --git a/llvm/test/DebugInfo/namespace_inline_function_definition.ll b/llvm/test/DebugInfo/namespace_inline_function_definition.ll
index 109994f8bd9..f186ed48c5a 100644
--- a/llvm/test/DebugInfo/namespace_inline_function_definition.ll
+++ b/llvm/test/DebugInfo/namespace_inline_function_definition.ll
@@ -42,7 +42,7 @@ entry:
   store i32 0, i32* %retval
   %0 = load i32, i32* @x, align 4, !dbg !16
   store i32 %0, i32* %i.addr.i, align 4
-  call void @llvm.dbg.declare(metadata i32* %i.addr.i, metadata !17, metadata !MDExpression()), !dbg !18
+  call void @llvm.dbg.declare(metadata i32* %i.addr.i, metadata !117, metadata !MDExpression()), !dbg !18
   %1 = load i32, i32* %i.addr.i, align 4, !dbg !18
   %mul.i = mul nsw i32 %1, 2, !dbg !18
   ret i32 %mul.i, !dbg !16
@@ -88,5 +88,8 @@ attributes #2 = { nounwind readnone }
 !15 = !{!"clang version 3.5.0 "}
 !16 = !MDLocation(line: 5, scope: !4)
 !17 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "i", line: 6, arg: 1, scope: !9, file: !5, type: !8)
+
+!117 = !MDLocalVariable(tag: DW_TAG_arg_variable, name: "i", line: 6, arg: 1, scope: !9, file: !5, type: !8, inlinedAt: !16)
+
 !18 = !MDLocation(line: 6, scope: !9, inlinedAt: !16)
 !19 = !MDLocation(line: 6, scope: !9)