Use the DWARF linkage name when importing C++ methods.

When importing C++ methods into clang AST nodes from the DWARF symbol
table, preserve the DW_AT_linkage_name and use it as the linker
("asm") name for the symbol.

Concretely, this enables `expression` to call into names that use the
GNU `abi_tag` extension, and enables lldb to call into code using
std::string or std::list from recent versions of libstdc++. See
https://bugs.llvm.org/show_bug.cgi?id=35310 . It also seems broadly
more robust than relying on the DWARF->clang->codegen pipeline to
roundtrip properly, but I'm not immediately aware of any other cases
in which it makes a difference.

Patch by Nelson Elhage!

Differential Revision:  https://reviews.llvm.org/D40283

1 files changed, 6 insertions, 1 deletions

diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
index df2d25c8d1e..56aa3f71b2b 100644
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -7889,7 +7889,7 @@ clang::VarDecl *ClangASTContext::AddVariableToRecordType(
 }
 
 clang::CXXMethodDecl *ClangASTContext::AddMethodToCXXRecordType(
-    lldb::opaque_compiler_type_t type, const char *name,
+    lldb::opaque_compiler_type_t type, const char *name, const char *mangled_name,
     const CompilerType &method_clang_type, lldb::AccessType access,
     bool is_virtual, bool is_static, bool is_inline, bool is_explicit,
     bool is_attr_used, bool is_artificial) {
@@ -8009,6 +8009,11 @@ clang::CXXMethodDecl *ClangASTContext::AddMethodToCXXRecordType(
   if (is_attr_used)
     cxx_method_decl->addAttr(clang::UsedAttr::CreateImplicit(*getASTContext()));
 
+  if (mangled_name != NULL) {
+    cxx_method_decl->addAttr(
+        clang::AsmLabelAttr::CreateImplicit(*getASTContext(), mangled_name));
+  }
+
   // Populate the method decl with parameter decls
 
   llvm::SmallVector<clang::ParmVarDecl *, 12> params;