Fix broken builtin functions in the expression command

Summary:
Calling any non-libc builtin function in the expression command currently just causes Clang
to state that the function is not known. The reason for this is that we actually never
initialize the list of builtin functions in the Builtin::Context.

This patch just calls the initializer for the builtins in the preprocessor. Also adds some tests
for the new builtins.

It also gets rid of the extra list of builtins in the ClangExpressionParser, as we can just reuse
the existing list in the Preprocessor for the ASTContext. Having just one list of builtins around
is also closer to the standard Clang behavior.

Reviewers: #lldb, vsk

Reviewed By: vsk

Subscribers: sgraenitz, clayborg, vsk, lldb-commits

Differential Revision: https://reviews.llvm.org/D50481

llvm-svn: 340571

2 files changed, 11 insertions, 4 deletions

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
index c5406fcc334..26dad943aef 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
@@ -508,12 +508,21 @@ ClangExpressionParser::ClangExpressionParser(ExecutionContextScope *exe_scope,
   // 8. Most of this we get from the CompilerInstance, but we also want to give
   // the context an ExternalASTSource.
   m_selector_table.reset(new SelectorTable());
-  m_builtin_context.reset(new Builtin::Context());
+
+  // We enable all builtin functions beside the builtins from libc/libm (e.g.
+  // 'fopen'). Those libc functions are already correctly handled by LLDB, and
+  // additionally enabling them as expandable builtins is breaking Clang.
+  m_compiler->getLangOpts().NoBuiltin = true;
+
+  auto &PP = m_compiler->getPreprocessor();
+  auto &builtin_context = PP.getBuiltinInfo();
+  builtin_context.initializeBuiltins(PP.getIdentifierTable(),
+                                     m_compiler->getLangOpts());
 
   std::unique_ptr<clang::ASTContext> ast_context(
       new ASTContext(m_compiler->getLangOpts(), m_compiler->getSourceManager(),
                      m_compiler->getPreprocessor().getIdentifierTable(),
-                     *m_selector_table.get(), *m_builtin_context.get()));
+                     *m_selector_table.get(), builtin_context));
 
   ast_context->InitBuiltinTypes(m_compiler->getTarget());
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
index 4058ec1270b..42106579e37 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
@@ -149,8 +149,6 @@ private:
       m_file_manager; ///< The Clang file manager object used by the compiler
   std::unique_ptr<clang::CompilerInstance>
       m_compiler; ///< The Clang compiler used to parse expressions into IR
-  std::unique_ptr<clang::Builtin::Context>
-      m_builtin_context; ///< Context for Clang built-ins
   std::unique_ptr<clang::SelectorTable>
       m_selector_table; ///< Selector table for Objective-C methods
   std::unique_ptr<clang::CodeGenerator>