#ifndef GO_BACKEND_H
#define GO_BACKEND_H
-class Function_type;
-class Struct_type;
-class Interface_type;
-
// Pointers to these types are created by the backend, passed to the
// frontend, and passed back to the backend. The types must be
// defined by the backend using these names.
// The backend representation of a label.
class Blabel;
-// A list of backend types.
-typedef std::vector<Btype*> Btypes;
-
// The backend interface. This is a pure abstract class that a
// specific backend will implement.
public:
virtual ~Backend() { }
+ // Name/type/location. Used for function parameters, struct fields,
+ // interface methods.
+ struct Btyped_identifier
+ {
+ std::string name;
+ Btype* btype;
+ Location location;
+
+ Btyped_identifier()
+ : name(), btype(NULL), location(UNKNOWN_LOCATION)
+ { }
+
+ Btyped_identifier(const std::string& a_name, Btype* a_btype,
+ Location a_location)
+ : name(a_name), btype(a_btype), location(a_location)
+ { }
+ };
+
// Types.
// Produce an error type. Actually the backend could probably just
virtual Btype*
integer_type(bool is_unsigned, int bits) = 0;
- // Get an unnamed floating point type with the given number of bits.
+ // Get an unnamed floating point type with the given number of bits
+ // (32 or 64).
virtual Btype*
float_type(int bits) = 0;
- // Get an unnamed complex type with the given number of bits.
+ // Get an unnamed complex type with the given number of bits (64 or 128).
virtual Btype*
complex_type(int bits) = 0;
- // Get the unnamed string type.
- virtual Btype*
- string_type() = 0;
-
// Get a pointer type.
virtual Btype*
- pointer_type(const Btype* to_type) = 0;
+ pointer_type(Btype* to_type) = 0;
// Get a function type. The receiver, parameter, and results are
// generated from the types in the Function_type. The Function_type
// is provided so that the names are available.
virtual Btype*
- function_type(const Function_type*, Btype* receiver,
- const Btypes* parameters,
- const Btypes* results) = 0;
+ function_type(const Btyped_identifier& receiver,
+ const std::vector<Btyped_identifier>& parameters,
+ const std::vector<Btyped_identifier>& results,
+ Location location) = 0;
- // Get a struct type. The Struct_type is provided to get the field
- // names.
+ // Get a struct type.
virtual Btype*
- struct_type(const Struct_type*, const Btypes* field_types) = 0;
+ struct_type(const std::vector<Btyped_identifier>& fields) = 0;
// Get an array type.
virtual Btype*
- array_type(const Btype* element_type, const Bexpression* length) = 0;
-
- // Get a slice type.
+ array_type(Btype* element_type, Bexpression* length) = 0;
+
+ // Create a placeholder pointer type. This is used for a named
+ // pointer type, since in Go a pointer type may refer to itself.
+ // NAME is the name of the type, and the location is where the named
+ // type is defined. This function is also used for unnamed function
+ // types with multiple results, in which case the type has no name
+ // and NAME will be empty. FOR_FUNCTION is true if this is for a Go
+ // function type, which corresponds to a C/C++ pointer to function
+ // type. The return value will later be passed as the first
+ // parameter to set_placeholder_pointer_type or
+ // set_placeholder_function_type.
virtual Btype*
- slice_type(const Btype* element_type) = 0;
-
- // Get a map type.
+ placeholder_pointer_type(const std::string& name, Location,
+ bool for_function) = 0;
+
+ // Fill in a placeholder pointer type as a pointer. This takes a
+ // type returned by placeholder_pointer_type and arranges for it to
+ // point to to_type. Returns true on success, false on failure.
+ virtual bool
+ set_placeholder_pointer_type(Btype* placeholder, Btype* to_type) = 0;
+
+ // Fill in a placeholder pointer type as a function. This takes a
+ // type returned by placeholder_pointer_type and arranges for it to
+ // become a real Go function type (which corresponds to a C/C++
+ // pointer to function type). FT will be something returned by the
+ // function_type method. Returns true on success, false on failure.
+ virtual bool
+ set_placeholder_function_type(Btype* placeholder, Btype* ft) = 0;
+
+ // Create a placeholder struct type. This is used for a named
+ // struct type, as with placeholder_pointer_type.
virtual Btype*
- map_type(const Btype* key_type, const Btype* value_type, source_location) = 0;
-
- // Get a channel type.
+ placeholder_struct_type(const std::string& name, Location) = 0;
+
+ // Fill in a placeholder struct type. This takes a type returned by
+ // placeholder_struct_type and arranges for it to become a real
+ // struct type. The parameter is as for struct_type. Returns true
+ // on success, false on failure.
+ virtual bool
+ set_placeholder_struct_type(Btype* placeholder,
+ const std::vector<Btyped_identifier>& fields)
+ = 0;
+
+ // Create a placeholder array type. This is used for a named array
+ // type, as with placeholder_pointer_type, to handle cases like
+ // type A []*A.
virtual Btype*
- channel_type(const Btype* element_type) = 0;
-
- // Get an interface type. The Interface_type is provided to get the
- // method names.
+ placeholder_array_type(const std::string& name, Location) = 0;
+
+ // Fill in a placeholder array type. This takes a type returned by
+ // placeholder_array_type and arranges for it to become a real array
+ // type. The parameters are as for array_type. Returns true on
+ // success, false on failure.
+ virtual bool
+ set_placeholder_array_type(Btype* placeholder, Btype* element_type,
+ Bexpression* length) = 0;
+
+ // Return a named version of a type. The location is the location
+ // of the type definition. This will not be called for a type
+ // created via placeholder_pointer_type, placeholder_struct_type, or
+ // placeholder_array_type.. (It may be called for a pointer,
+ // struct, or array type in a case like "type P *byte; type Q P".)
virtual Btype*
- interface_type(const Interface_type*, const Btypes* method_types) = 0;
+ named_type(const std::string& name, Btype*, Location) = 0;
+
+ // Create a marker for a circular pointer type. Go pointer and
+ // function types can refer to themselves in ways that are not
+ // permitted in C/C++. When a circular type is found, this function
+ // is called for the circular reference. This permits the backend
+ // to decide how to handle such a type. PLACEHOLDER is the
+ // placeholder type which has already been created; if the backend
+ // is prepared to handle a circular pointer type, it may simply
+ // return PLACEHOLDER. FOR_FUNCTION is true if this is for a
+ // function type.
+ //
+ // For "type P *P" the sequence of calls will be
+ // bt1 = placeholder_pointer_type();
+ // bt2 = circular_pointer_type(bt1, false);
+ // set_placeholder_pointer_type(bt1, bt2);
+ virtual Btype*
+ circular_pointer_type(Btype* placeholder, bool for_function) = 0;
+
+ // Return whether the argument could be a special type created by
+ // circular_pointer_type. This is used to introduce explicit type
+ // conversions where needed. If circular_pointer_type returns its
+ // PLACEHOLDER parameter, this may safely always return false.
+ virtual bool
+ is_circular_pointer_type(Btype*) = 0;
+
+ // Return the size of a type.
+ virtual size_t
+ type_size(Btype*) = 0;
+
+ // Return the alignment of a type.
+ virtual size_t
+ type_alignment(Btype*) = 0;
+
+ // Return the alignment of a struct field of this type. This is
+ // normally the same as type_alignment, but not always.
+ virtual size_t
+ type_field_alignment(Btype*) = 0;
+
+ // Return the offset of field INDEX in a struct type. INDEX is the
+ // entry in the FIELDS std::vector parameter of struct_type or
+ // set_placeholder_struct_type.
+ virtual size_t
+ type_field_offset(Btype*, size_t index) = 0;
+
+ // Expressions.
+
+ // Return an expression for a zero value of the given type. This is
+ // used for cases such as local variable initialization and
+ // converting nil to other types.
+ virtual Bexpression*
+ zero_expression(Btype*) = 0;
// Statements.
// Create an assignment statement.
virtual Bstatement*
assignment_statement(Bexpression* lhs, Bexpression* rhs,
- source_location) = 0;
+ Location) = 0;
// Create a return statement, passing the representation of the
// function and the list of values to return.
virtual Bstatement*
return_statement(Bfunction*, const std::vector<Bexpression*>&,
- source_location) = 0;
+ Location) = 0;
// Create an if statement. ELSE_BLOCK may be NULL.
virtual Bstatement*
if_statement(Bexpression* condition, Bblock* then_block, Bblock* else_block,
- source_location) = 0;
+ Location) = 0;
// Create a switch statement where the case values are constants.
// CASES and STATEMENTS must have the same number of entries. If
switch_statement(Bexpression* value,
const std::vector<std::vector<Bexpression*> >& cases,
const std::vector<Bstatement*>& statements,
- source_location) = 0;
+ Location) = 0;
// Create a single statement from two statements.
virtual Bstatement*
virtual Bblock*
block(Bfunction* function, Bblock* enclosing,
const std::vector<Bvariable*>& vars,
- source_location start_location, source_location end_location) = 0;
+ Location start_location, Location end_location) = 0;
// Add the statements to a block. The block is created first. Then
// the statements are created. Then the statements are added to the
Btype* btype,
bool is_external,
bool is_hidden,
- source_location location) = 0;
+ Location location) = 0;
// A global variable will 1) be initialized to zero, or 2) be
// initialized to a constant value, or 3) be initialized in the init
// Create a local variable. The frontend will create the local
// variables first, and then create the block which contains them.
// FUNCTION is the function in which the variable is defined. NAME
- // is the name of the variable. TYPE is the type. LOCATION is
- // where the variable is defined. For each local variable the
- // frontend will call init_statement to set the initial value.
+ // is the name of the variable. TYPE is the type. IS_ADDRESS_TAKEN
+ // is true if the address of this variable is taken (this implies
+ // that the address does not escape the function, as otherwise the
+ // variable would be on the heap). LOCATION is where the variable
+ // is defined. For each local variable the frontend will call
+ // init_statement to set the initial value.
virtual Bvariable*
local_variable(Bfunction* function, const std::string& name, Btype* type,
- source_location location) = 0;
+ bool is_address_taken, Location location) = 0;
// Create a function parameter. This is an incoming parameter, not
// a result parameter (result parameters are treated as local
// variables). The arguments are as for local_variable.
virtual Bvariable*
parameter_variable(Bfunction* function, const std::string& name,
- Btype* type, source_location location) = 0;
+ Btype* type, bool is_address_taken,
+ Location location) = 0;
// Create a temporary variable. A temporary variable has no name,
// just a type. We pass in FUNCTION and BLOCK in case they are
// *PSTATEMENT to a statement which initializes the variable.
virtual Bvariable*
temporary_variable(Bfunction*, Bblock*, Btype*, Bexpression* init,
- bool address_is_taken, source_location location,
+ bool address_is_taken, Location location,
Bstatement** pstatement) = 0;
+ // Create a named immutable initialized data structure. This is
+ // used for type descriptors and map descriptors. This returns a
+ // Bvariable because it corresponds to an initialized const global
+ // variable in C.
+ //
+ // NAME is the name to use for the initialized global variable which
+ // this call will create.
+ //
+ // IS_COMMON is true if NAME may be defined by several packages, and
+ // the linker should merge all such definitions. If IS_COMMON is
+ // false, NAME should be defined in only one file. In general
+ // IS_COMMON will be true for the type descriptor of an unnamed type
+ // or a builtin type.
+ //
+ // TYPE will be a struct type; the type of the returned expression
+ // must be a pointer to this struct type.
+ //
+ // We must create the named structure before we know its
+ // initializer, because the initializer may refer to its own
+ // address. After calling this the frontend will call
+ // immutable_struct_set_init.
+ virtual Bvariable*
+ immutable_struct(const std::string& name, bool is_common, Btype* type,
+ Location) = 0;
+
+ // Set the initial value of a variable created by immutable_struct.
+ // The NAME, IS_COMMON, TYPE, and location parameters are the same
+ // ones passed to immutable_struct. INITIALIZER will be a composite
+ // literal of type TYPE. It will not contain any function calls or
+ // anything else which can not be put into a read-only data section.
+ // It may contain the address of variables created by
+ // immutable_struct.
+ virtual void
+ immutable_struct_set_init(Bvariable*, const std::string& name,
+ bool is_common, Btype* type, Location,
+ Bexpression* initializer) = 0;
+
+ // Create a reference to a named immutable initialized data
+ // structure defined in some other package. This will be a
+ // structure created by a call to immutable_struct with the same
+ // NAME and TYPE and with IS_COMMON passed as false. This
+ // corresponds to an extern const global variable in C.
+ virtual Bvariable*
+ immutable_struct_reference(const std::string& name, Btype* type,
+ Location) = 0;
+
// Labels.
// Create a new label. NAME will be empty if this is a label
// created by the frontend for a loop construct. The location is
// where the the label is defined.
virtual Blabel*
- label(Bfunction*, const std::string& name, source_location) = 0;
+ label(Bfunction*, const std::string& name, Location) = 0;
// Create a statement which defines a label. This statement will be
// put into the codestream at the point where the label should be
// Create a goto statement to a label.
virtual Bstatement*
- goto_statement(Blabel*, source_location) = 0;
+ goto_statement(Blabel*, Location) = 0;
// Create an expression for the address of a label. This is used to
// get the return address of a deferred function which may call
// recover.
virtual Bexpression*
- label_address(Blabel*, source_location) = 0;
+ label_address(Blabel*, Location) = 0;
};
// The backend interface has to define this function.
OSDN Git Service
