Commit Graph

3 Commits

Author SHA1 Message Date
Duncan P. N. Exon Smith
9b18dbfe83 Optimize metadata node fields for CHECK-ability
While gaining practical experience hand-updating CHECK lines (for moving
the new debug info hierarchy into place),  I learnt a few things about
CHECK-ability of the specialized node assembly output.

  - The first part of a `CHECK:` is to identify the "right" node (this
    is especially true if you intend to use the new `CHECK-SAME`
    feature, since the first CHECK needs to identify the node correctly
    before you can split the line).
      - If there's a `tag:`, it should go first.
      - If there's a `name:`, it should go next (followed by the
        `linkageName:`, if any).
      - If there's a `scope:`, it should follow after that.
  - When a node type supports multiple DW_TAGs, but one is implied by
    its name and is overwhelmingly more common, the `tag:` field is
    terribly uninteresting unless it's different.
      - `MDBasicType` is almost always `DW_TAG_base_type`.
      - `MDTemplateValueParameter` is almost always
        `DW_TAG_template_value_parameter`.
  - Printing `name: ""` doesn't improve CHECK-ability, and there are far
    more nodes than I realized that are commonly nameless.
  - There are a few other fields that similarly aren't very interesting
    when they're empty.

This commit updates the `AsmWriter` as suggested above (and makes
necessary changes in `LLParser` for round-tripping).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230877 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-28 23:21:38 +00:00
Duncan P. N. Exon Smith
99f12691dd IR: Change MDFile to directly store the filename/directory
In the old (well, current) schema, there are two types of file
references: untagged and tagged (the latter references the former).

    !0 = !{!"filename", !"/directory"}
    !1 = !{!"0x29", !1} ; DW_TAG_file_type [filename] [/directory]

The interface to `DIBuilder` universally takes the tagged version,
described by `DIFile`.  However, most `file:` references actually use
the untagged version directly.

In the new hierarchy, I'm merging this into a single node: `MDFile`.

Originally I'd planned to keep the old schema unchanged until after I
moved the new hierarchy into place.

However, it turns out to be trivial to make `MDFile` match both nodes at
the same time.

  - Anyone referencing !1 does so through `DIFile`, whose implementation
    I need to gut anyway (as I do the rest of the `DIDescriptor`s).
  - Anyone referencing !0 just references an `MDNode`, and expects a
    node with two `MDString` operands.

This commit achieves that, and updates all the testcases for the parts
of the new hierarchy that used the two-node schema (I've replaced the
untagged nodes with `distinct !{}` to make the diff clear (otherwise the
metadata all gets renumbered); it might be worthwhile to come back and
delete those nodes and renumber the world, not sure).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230057 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-20 20:35:17 +00:00
Duncan P. N. Exon Smith
fbc547da81 AsmWriter/Bitcode: MDGlobalVariable
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229020 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-13 01:35:40 +00:00