Read template parameters for structure types

Read DW_TAG_template_type_parameter and apply to structure types.

Author: tromey

lldb/include/lldb/Symbol/RustASTContext.h

@@ -132,6 +132,8 @@ class RustASTContext : public TypeSystem {
                         bool is_default, uint64_t discriminant);
   void FinishAggregateInitialization(const CompilerType &type);
 
+  void AddTemplateParameter(const CompilerType &type, const CompilerType &param);
+
   bool TypeHasDiscriminant(const CompilerType &type);
   bool IsTupleType(const CompilerType &type);
 
@@ -327,10 +329,15 @@ class RustASTContext : public TypeSystem {
                                 const char *name, bool omit_empty_base_classes,
                                 std::vector<uint32_t> &child_indexes) override;
 
-  size_t GetNumTemplateArguments(lldb::opaque_compiler_type_t type) override {
-    return 0;
+  lldb::TemplateArgumentKind GetTemplateArgumentKind(lldb::opaque_compiler_type_t type,
+						     size_t idx) override {
+    // Rust currently only has types.
+    return lldb::eTemplateArgumentKindType;
   }
 
+  CompilerType GetTypeTemplateArgument(lldb::opaque_compiler_type_t type, size_t idx) override;
+  size_t GetNumTemplateArguments(lldb::opaque_compiler_type_t type) override;
+
   //----------------------------------------------------------------------
   // Dumping types
   //----------------------------------------------------------------------

lldb/packages/Python/lldbsuite/test/lang/rust/types/TestRustASTContext.py

@@ -26,6 +26,7 @@ def test_with_dsym_and_python_api(self):
         self.check_main_function()
         self.check_structs()
         self.check_enums()
+        self.check_generics()
 
     def setUp(self):
         # Call super's setUp().
@@ -167,7 +168,14 @@ def check_enums(self):
             # See https://github.com/rust-lang-nursery/lldb/issues/24
             # self.assertEqual(name, v.GetType().name)
             self.assertEqual(size, v.GetType().GetByteSize())
+            self.assertEqual(0, v.GetType().num_template_args)
             # Some values can't really be checked.
             if value is not None:
                 expected = "(" + name + ") " + vname + " = " + value
                 self.assertEqual(expected, str(v.dynamic))
+
+    def check_generics(self):
+        t = self.var('vgeneric').GetType()
+        self.assertEqual(1, t.num_template_args)
+        self.assertEqual('T', t.template_args[0].name)
+        self.assertEqual('i32', t.template_args[0].GetTypedefedType().name)

lldb/packages/Python/lldbsuite/test/lang/rust/types/main.rs

@@ -32,6 +32,8 @@ pub enum OptimizedEnum {
     NonNull(Box<u8>)
 }
 
+pub struct Generic<T>(T);
+
 fn main() {
     let vbool: bool = true;
 
@@ -72,5 +74,7 @@ fn main() {
     let voptenum = OptimizedEnum::Null;
     let voptenum2 = OptimizedEnum::NonNull(Box::new(7));
 
+    let vgeneric = Generic(23i32);
+
     do_nothing();               // breakpoint
 }

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserRust.cpp

@@ -491,7 +491,7 @@ std::vector<DWARFASTParserRust::Field>
 DWARFASTParserRust::ParseFields(const DWARFDIE &die, std::vector<size_t> &discriminant_path,
 				bool &is_tuple,
 				uint64_t &discr_offset, uint64_t &discr_byte_size,
-				bool &saw_discr) {
+				bool &saw_discr, std::vector<CompilerType> &template_params) {
   SymbolFileDWARF *dwarf = die.GetDWARF();
 
   // We construct a list of fields and then apply them later so that
@@ -631,8 +631,8 @@ DWARFASTParserRust::ParseFields(const DWARFDIE &die, std::vector<size_t> &discri
       // New-style enum representation -- nothing useful is in the
       // enclosing struct, so we can just recurse here.
       return ParseFields(child_die, discriminant_path, is_tuple,
-			 discr_offset, discr_byte_size, saw_discr);
-    } else {
+			 discr_offset, discr_byte_size, saw_discr, template_params);
+    } else if (child_die.Tag() == DW_TAG_member) {
       if (new_field.is_discriminant) {
 	// Don't check this field name, and don't increment field_index.
 	// When we see a tuple with fields like
@@ -650,6 +650,11 @@ DWARFASTParserRust::ParseFields(const DWARFDIE &die, std::vector<size_t> &discri
       }
 
       fields.push_back(new_field);
+    } else if (child_die.Tag() == DW_TAG_template_type_parameter) {
+      Type *param_type = dwarf->ResolveTypeUID(child_die, true);
+      if (param_type) {
+	template_params.push_back(param_type->GetForwardCompilerType());
+      }
     }
   }
 
@@ -728,8 +733,10 @@ TypeSP DWARFASTParserRust::ParseStructureType(const DWARFDIE &die) {
   bool saw_discr = false;
   uint64_t discr_offset, discr_byte_size;
   std::vector<size_t> discriminant_path;
+  std::vector<CompilerType> template_params;
   std::vector<Field> fields = ParseFields(die, discriminant_path, is_tuple,
-					  discr_offset, discr_byte_size, saw_discr);
+					  discr_offset, discr_byte_size, saw_discr,
+					  template_params);
 
   // This is true if this is a union, there are multiple fields and
   // each field's type has a discriminant.
@@ -834,6 +841,9 @@ TypeSP DWARFASTParserRust::ParseStructureType(const DWARFDIE &die) {
     }
   }
 
+  for (const CompilerType &param_type : template_params)
+    m_ast.AddTemplateParameter(compiler_type, param_type);
+
   m_ast.FinishAggregateInitialization(compiler_type);
 
   // Add our type to the unique type map so we don't

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserRust.h

@@ -104,7 +104,8 @@ class DWARFASTParserRust : public DWARFASTParser {
 				 std::vector<size_t> &discriminant_path,
 				 bool &is_tuple,
 				 uint64_t &discr_offset, uint64_t &discr_byte_size,
-				 bool &saw_discr);
+				 bool &saw_discr,
+				 std::vector<lldb_private::CompilerType> &template_params);
 
   lldb_private::RustASTContext &m_ast;
 

lldb/source/Symbol/RustASTContext.cpp

@@ -400,6 +400,10 @@ class RustAggregateBase : public RustType {
     m_fields.emplace_back(name, type, offset);
   }
 
+  void AddTemplateParameter(const CompilerType &ctype) {
+    m_template_args.push_back(ctype);
+  }
+
   virtual void FinishInitialization() {
   }
 
@@ -423,6 +427,14 @@ class RustAggregateBase : public RustType {
     return &m_fields[idx];
   }
 
+  size_t GetNumTemplateArguments() const {
+    return m_template_args.size();
+  }
+
+  CompilerType GetTypeTemplateArgument(size_t idx) const {
+    return m_template_args[idx];
+  }
+
   typedef std::vector<Field>::const_iterator const_iterator;
 
   const_iterator begin() const {
@@ -472,6 +484,7 @@ class RustAggregateBase : public RustType {
   uint64_t m_byte_size;
   std::vector<Field> m_fields;
   bool m_has_discriminant;
+  std::vector<CompilerType> m_template_args;
 };
 
 class RustTuple : public RustAggregateBase {
@@ -2148,3 +2161,36 @@ bool RustASTContext::GetCABITypeDeclaration(CompilerType type, const std::string
   *result = rtype->GetCABITypeDeclaration(name_map, varname);
   return true;
 }
+
+CompilerType RustASTContext::GetTypeTemplateArgument(lldb::opaque_compiler_type_t type,
+						     size_t idx) {
+  if (type) {
+    RustType *t = static_cast<RustType *>(type);
+    if (RustAggregateBase *a = t->AsAggregate()) {
+      return a->GetTypeTemplateArgument(idx);
+    }
+  }
+  return CompilerType();
+}
+
+size_t RustASTContext::GetNumTemplateArguments(lldb::opaque_compiler_type_t type) {
+  if (type) {
+    RustType *t = static_cast<RustType *>(type);
+    if (RustAggregateBase *a = t->AsAggregate()) {
+      return a->GetNumTemplateArguments();
+    }
+  }
+  return 0;
+}
+
+void RustASTContext::AddTemplateParameter(const CompilerType &type, const CompilerType &param) {
+  if (!type)
+    return;
+  RustASTContext *ast = llvm::dyn_cast_or_null<RustASTContext>(type.GetTypeSystem());
+  if (!ast)
+    return;
+  RustType *t = static_cast<RustType *>(type.GetOpaqueQualType());
+  if (RustAggregateBase *a = t->AsAggregate()) {
+    a->AddTemplateParameter(param);
+  }
+}