Commit 7f7b2966 authored by Raphael Isemann's avatar Raphael Isemann
Browse files

[lldb] Reland "Refactor guard variable checks in IRForTarget" 

It seems the broken guard variable check for Windows was a feature(TM)
and not a bug, so let's keep add a flag to the guard check that keeps
the old behavior in the places where we ignored guard variables before.

llvm-svn: 368688
parent 73f702ff

lldb/source/Plugins/ExpressionParser/Clang/IRForTarget.cpp

+19 −14
Original line number Diff line number Diff line
@@ -155,6 +155,15 @@ clang::NamedDecl *IRForTarget::DeclForGlobal(GlobalValue *global_val) { 
  return DeclForGlobal(global_val, m_module);

}



/// Returns true iff the mangled symbol is for a static guard variable.

static bool isGuardVariableSymbol(llvm::StringRef mangled_symbol,

                                  bool check_ms_abi = true) {

  bool result = mangled_symbol.startswith("_ZGV"); // Itanium ABI guard variable

  if (check_ms_abi)

    result |= mangled_symbol.startswith("@4IA"); // Microsoft ABI

  return result;

}



bool IRForTarget::CreateResultVariable(llvm::Function &llvm_function) {

  lldb_private::Log *log(

      lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_EXPRESSIONS));
@@ -172,15 +181,17 @@ bool IRForTarget::CreateResultVariable(llvm::Function &llvm_function) { 
  for (StringMapEntry<llvm::Value *> &value_symbol : value_symbol_table) {

    result_name = value_symbol.first();



    if (result_name.contains("$__lldb_expr_result_ptr") &&

        !result_name.startswith("_ZGV")) {

    // Check if this is a guard variable. It seems this causes some hiccups

    // on Windows, so let's only check for Itanium guard variables.

    bool is_guard_var = isGuardVariableSymbol(result_name, /*MS ABI*/ false);



    if (result_name.contains("$__lldb_expr_result_ptr") && !is_guard_var) {

      found_result = true;

      m_result_is_pointer = true;

      break;

    }



    if (result_name.contains("$__lldb_expr_result") &&

        !result_name.startswith("_ZGV")) {

    if (result_name.contains("$__lldb_expr_result") && !is_guard_var) {

      found_result = true;

      m_result_is_pointer = false;

      break;
@@ -1528,14 +1539,12 @@ bool IRForTarget::ResolveExternals(Function &llvm_function) { 
}



static bool isGuardVariableRef(Value *V) {

  Constant *Old = nullptr;

  Constant *Old = dyn_cast<Constant>(V);



  if (!(Old = dyn_cast<Constant>(V)))

  if (!Old)

    return false;



  ConstantExpr *CE = nullptr;



  if ((CE = dyn_cast<ConstantExpr>(V))) {

  if (auto CE = dyn_cast<ConstantExpr>(V)) {

    if (CE->getOpcode() != Instruction::BitCast)

      return false;
@@ -1544,12 +1553,8 @@ static bool isGuardVariableRef(Value *V) { 


  GlobalVariable *GV = dyn_cast<GlobalVariable>(Old);



  if (!GV || !GV->hasName() ||

      (!GV->getName().startswith("_ZGV") && // Itanium ABI guard variable

       !GV->getName().endswith("@4IA")))    // Microsoft ABI guard variable

  {

  if (!GV || !GV->hasName() || !isGuardVariableSymbol(GV->getName()))

    return false;

  }



  return true;

}