[lldb] Add option to retry Fix-Its multiple times to failed expressions

Summary:
Usually when Clang emits an error Fix-It it does two things. It emits the diagnostic and then it fixes the
currently generated AST to reflect the applied Fix-It. While emitting the diagnostic is easy to implement,
fixing the currently generated AST is often tricky. That causes that some Fix-Its just keep the AST as-is or
abort the parsing process entirely. Once the parser stopped, any Fix-Its for the rest of the expression are
not detected and when the user manually applies the Fix-It, the next expression will just produce a new
Fix-It.

This is often occurring with quickly made Fix-Its that are just used to bridge temporary API changes
and that often are not worth implementing a proper API fixup in addition to the diagnostic. To still
give some kind of reasonable user-experience for users that have these Fix-Its and rely on them to
fix their expressions, this patch adds the ability to retry parsing with applied Fix-Its multiple time to
give the normal Fix-It experience where things Clang knows how to fix are not causing actual expression
error (at least when automatically applying Fix-Its is activated).

The way this is implemented is just by having another setting in the expression options that specify how
often we should try applying Fix-Its and then reparse the expression. The default setting is still 1 for everyone
so this should not affect the speed in which we fail to parse expressions.

Reviewers: jingham, JDevlieghere, friss, shafik

Reviewed By: shafik

Subscribers: shafik, abidh

Differential Revision: https://reviews.llvm.org/D77214

1 files changed, 1 insertions, 0 deletions

diff --git a/lldb/source/Commands/CommandObjectExpression.cpp b/lldb/source/Commands/CommandObjectExpression.cpp
index 9a314c2..7cec714 100644
--- a/lldb/source/Commands/CommandObjectExpression.cpp
+++ b/lldb/source/Commands/CommandObjectExpression.cpp
@@ -385,6 +385,7 @@ CommandObjectExpression::GetEvalOptions(const Target &target) {
     auto_apply_fixits = m_command_options.auto_apply_fixits == eLazyBoolYes;
 
   options.SetAutoApplyFixIts(auto_apply_fixits);
+  options.SetRetriesWithFixIts(target.GetNumberOfRetriesWithFixits());
 
   if (m_command_options.top_level)
     options.SetExecutionPolicy(eExecutionPolicyTopLevel);