[Lldb-commits] [PATCH] D129078: WIP: [LLDB][ClangExpression] Allow expression evaluation from within C++ Lambdas

[Michael Buch via Phabricator via lldb-commits]

Michael137 created this revision.
Michael137 added reviewers: aprantl, jingham.
Herald added a project: All.
Michael137 requested review of this revision.
Herald added a reviewer: jdoerfert.
Herald added subscribers: lldb-commits, sstefan1.
Herald added a project: LLDB.

This patch adds support for evaluating expressions which reference
a captured `this` from within the context of a C++ lambda expression.
Currently LLDB doesn't provide Clang with enough information to
determine that we're inside a lambda expression and are allowed to
access variables on a captured `this`; instead Clang simply fails
to parse the expression.

There are two problems to solve here:

1. Make sure `clang::Sema` doesn't reject the expression due to illegal member access.
2. Materialize all the necessary captured variables/member variables required to evaluate the expression.

To address (1), we currently import the outer structure's AST context
onto `$__lldb_class`, making the `contextClass` and the `NamingClass`
match, a requirement by `clang::Sema::BuildPossibleImplicitMemberExpr`.

To address (2), we inject all captured variables as locals into the
expression source code.

**Testing**

- Added API test


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D129078

Files:
  lldb/include/lldb/Expression/Materializer.h
  lldb/include/lldb/Expression/UserExpression.h
  lldb/source/Expression/Materializer.cpp
  lldb/source/Expression/UserExpression.cpp
  lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.cpp
  lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionDeclMap.h
  lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.cpp
  lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionSourceCode.h
  lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionVariable.h
  lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
  lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.h
  lldb/test/API/commands/expression/expr_inside_lambda/Makefile
  lldb/test/API/commands/expression/expr_inside_lambda/TestExprInsideLambdas.py
  lldb/test/API/commands/expression/expr_inside_lambda/main.cpp

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