[clangd] Add dlog()s for SelectionTree, enabling -debug-only=SelectionTree.cpp
Summary:
SelectionTree is a RecursiveASTVisitor which processes getSourceRange() for
every node. This is a lot of surface area with the AST, as getSourceRange()
is specialized for *many* node types.
And the resulting SelectionTree depends on the source ranges of many
visited nodes, and the order of traversal.
Put together, this means we really need a traversal log to debug when we
get an unexpected SelectionTree. I've built this ad-hoc a few times, now
it's time to check it in.
Example output:
```
D[14:07:44.184] Computing selection for </usr/local/google/home/sammccall/test.cc:1:7, col:8>
D[14:07:44.184] push: VarDecl const auto x = 42
D[14:07:44.184] claimRange: </usr/local/google/home/sammccall/test.cc:1:12, col:13>
D[14:07:44.184] push: NestedNameSpecifierLoc (empty NestedNameSpecifierLoc)
D[14:07:44.184] pop: NestedNameSpecifierLoc (empty NestedNameSpecifierLoc)
D[14:07:44.184] push: QualifiedTypeLoc const auto
D[14:07:44.184] pop: QualifiedTypeLoc const auto
D[14:07:44.184] claimRange: </usr/local/google/home/sammccall/test.cc:1:7, col:11>
D[14:07:44.184] hit selection: </usr/local/google/home/sammccall/test.cc:1:7, col:8>
D[14:07:44.184] skip: IntegerLiteral 42
D[14:07:44.184] skipped range = </usr/local/google/home/sammccall/test.cc:1:16>
D[14:07:44.184] pop: VarDecl const auto x = 42
D[14:07:44.184] claimRange: </usr/local/google/home/sammccall/test.cc:1:1, col:18>
D[14:07:44.184] skip: VarDecl int y = 43
D[14:07:44.184] skipped range = </usr/local/google/home/sammccall/test.cc:2:1, col:9>
D[14:07:44.184] Built selection tree
TranslationUnitDecl
VarDecl const auto x = 42
.QualifiedTypeLoc const auto
```
Reviewers: hokein
Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65073
git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@366698 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
