Refactor GetNextPersistentVariableName into a non-virtual method

that takes a prefix string. This simplifies the implementation and
allows plugins such as the Swift plugin to supply different prefixes
for return and error variables.

rdar://problem/39299889

Differential Revision: https://reviews.llvm.org/D46088

llvm-svn: 331235

5 files changed, 13 insertions, 32 deletions

diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
index 34fc7a19f110..bb73d55a9a41 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.cpp
@@ -53,15 +53,6 @@ void ClangPersistentVariables::RemovePersistentVariable(
     m_next_persistent_variable_id--;
 }
 
-ConstString
-ClangPersistentVariables::GetNextPersistentVariableName(Target &target) {
-  char name_cstr[256];
-  ::snprintf(name_cstr, sizeof(name_cstr), "$%u",
-             target.GetNextPersistentVariableIndex());
-  ConstString name(name_cstr);
-  return name;
-}
-
 void ClangPersistentVariables::RegisterPersistentDecl(const ConstString &name,
                                                       clang::NamedDecl *decl) {
   m_persistent_decls.insert(
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
index a9a4a3c1a5f3..1432fae711ed 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangPersistentVariables.h
@@ -54,16 +54,11 @@ public:
       const CompilerType &compiler_type, lldb::ByteOrder byte_order,
       uint32_t addr_byte_size) override;
 
-  //----------------------------------------------------------------------
-  /// Return the next entry in the sequence of strings "$0", "$1", ... for
-  /// use naming persistent expression convenience variables.
-  ///
-  /// @return
-  ///     A string that contains the next persistent variable name.
-  //----------------------------------------------------------------------
-  ConstString GetNextPersistentVariableName(Target &target) override;
-
   void RemovePersistentVariable(lldb::ExpressionVariableSP variable) override;
+  llvm::StringRef
+  GetPersistentVariablePrefix(bool is_error) const override {
+    return "$";
+  }
 
   void RegisterPersistentDecl(const ConstString &name, clang::NamedDecl *decl);
 
diff --git a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
index 0062bb8661e5..4da5492b14d3 100644
--- a/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Clang/ClangUserExpression.cpp
@@ -665,7 +665,9 @@ void ClangUserExpression::ClangUserExpressionHelper::CommitPersistentDecls() {
 }
 
 ConstString ClangUserExpression::ResultDelegate::GetName() {
-  return m_persistent_state->GetNextPersistentVariableName(*m_target_sp);
+  auto prefix = m_persistent_state->GetPersistentVariablePrefix();
+  return m_persistent_state->GetNextPersistentVariableName(*m_target_sp,
+                                                           prefix);
 }
 
 void ClangUserExpression::ResultDelegate::DidDematerialize(
diff --git a/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.cpp b/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.cpp
index 43ac4c6747a0..9212e18bd84d 100644
--- a/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.cpp
+++ b/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.cpp
@@ -272,7 +272,8 @@ GoUserExpression::DoExecute(DiagnosticManager &diagnostic_manager,
   PersistentExpressionState *pv =
       target->GetPersistentExpressionStateForLanguage(eLanguageTypeGo);
   if (pv != nullptr) {
-    result->SetName(pv->GetNextPersistentVariableName(*target));
+    result->SetName(pv->GetNextPersistentVariableName(
+        *target, pv->GetPersistentVariablePrefix()));
     pv->AddVariable(result);
   }
   return lldb::eExpressionCompleted;
@@ -650,16 +651,6 @@ ValueObjectSP GoUserExpression::GoInterpreter::VisitCallExpr(
 GoPersistentExpressionState::GoPersistentExpressionState()
     : PersistentExpressionState(eKindGo) {}
 
-ConstString
-GoPersistentExpressionState::GetNextPersistentVariableName(Target &target) {
-  char name_cstr[256];
-  // We can't use the same variable format as clang.
-  ::snprintf(name_cstr, sizeof(name_cstr), "$go%u",
-             target.GetNextPersistentVariableIndex());
-  ConstString name(name_cstr);
-  return name;
-}
-
 void GoPersistentExpressionState::RemovePersistentVariable(
     lldb::ExpressionVariableSP variable) {
   RemoveVariable(variable);
diff --git a/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.h b/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.h
index 28c00215ed72..5d55b296ed34 100644
--- a/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.h
+++ b/lldb/source/Plugins/ExpressionParser/Go/GoUserExpression.h
@@ -29,8 +29,10 @@ class GoPersistentExpressionState : public PersistentExpressionState {
 public:
   GoPersistentExpressionState();
 
-  ConstString GetNextPersistentVariableName(Target &target) override;
-
+  llvm::StringRef
+  GetPersistentVariablePrefix(bool is_error) const override {
+    return "$go";
+  }
   void RemovePersistentVariable(lldb::ExpressionVariableSP variable) override;
 
   lldb::addr_t LookupSymbol(const ConstString &name) override {