[all-commits] [llvm/llvm-project] a13aa0: [lldb] Fix dwim-print's arrow-operator check to ma...

[Yao Qi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a13aa07af6d0527a14cdc2e2f3fe4ec3d0ccb362
      https://github.com/llvm/llvm-project/commit/a13aa07af6d0527a14cdc2e2f3fe4ec3d0ccb362
  Author: Yao Qi <yao_qi at apple.com>
  Date:   2026-09-23 (Wed, 23 Sep 2026)

  Changed paths:
    M lldb/source/Commands/CommandObjectDWIMPrint.cpp
    M lldb/test/API/commands/dwim-print/TestDWIMPrint.py

  Log Message:
  -----------
  [lldb] Fix dwim-print's arrow-operator check to match the substring (#225778)

`CommandObjectDWIMPrint::DoExecute` decides whether to try `expr` as a
limited, dot-only frame variable path before falling back to full
expression evaluation. The comment above the check says a variable
path is not attempted if `expr` contains the arrow operator (`->`) or
the subscript operator (`[]`), or a bare `*` or `&`:
```
    const bool try_variable_path =
        expr.find_first_of("*&->[]") == StringRef::npos;
```
`find_first_of` treats its argument as a set of characters so this also
matches a lone `-` or a lone `>` anywhere in `expr`, not only the
two-character `->` sequence the comment describes.

Fix the check to test for the `->` substring directly with
`StringRef::contains`, keeping `find_first_of` only for the four
characters that are genuinely excluded one at a time (`*`, `&`, `[`,
`]`).

By itself, this widens which expressions attempt the variable-path
fast path (anything with a lone `-` or `>` now does).
Ordinary arithmetic and comparison expressions containing a lone `-`
or `>` now correctly attempt, and correctly fail, the variable-path
fast path before falling through to `expression`, shown here
```
    frame #0: liblldb.24.0git.dylib`lldb_private::CommandObjectDWIMPrint::DoExecute(this=<unavailable>, command=<unavailable>, result=<unavailable>) at CommandObjectDWIMPrint.cpp:169:13 [opt]
    (lldb) settings set dwim-print-verbosity full
    (lldb) dwim-print expr
    note: ran `frame variable expr`
    (llvm::StringRef)  (Data = "1+1", Length = 3)
    (lldb) dwim-print expr.Length-1
    warning: `this' is not accessible (substituting 0). Couldn't load 'this' because its value couldn't be evaluated
    note: ran `expression expr.Length-1`
    (size_t) 2
    (lldb) dwim-print expr.Length>0
    warning: `this' is not accessible (substituting 0). Couldn't load 'this' because its value couldn't be evaluated
    note: ran `expression expr.Length>0`
    (bool) true
    (lldb) dwim-print frame->m_frame_index
    warning: `this' is not accessible (substituting 0). Couldn't load 'this' because its value couldn't be evaluated
    note: ran `expression frame->m_frame_index`
    (uint32_t) 0
```
Add more expressions in `TestDWIMPrint.test_expressions`, to cover
expressions
containing a lone `-` or `>`.  Note that these tests can't tell "the
expression is evaluated by DIL but failed" and "expression isn't
evaluated by DIL at all".



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