//
// codegen.cs: The code generator
//
// Author:
// Miguel de Icaza (miguel@ximian.com)
//
// (C) 2001 Ximian, Inc.
//
using System;
using System.Collections;
using System.Reflection;
using System.Reflection.Emit;
using System.Diagnostics.SymbolStore;
namespace Mono.CSharp {
///
/// Code generator class.
///
public class CodeGen {
AppDomain current_domain;
AssemblyBuilder assembly_builder;
ModuleBuilder module_builder;
public ISymbolWriter SymbolWriter;
public static string Basename (string name)
{
int pos = name.LastIndexOf ("/");
if (pos != -1)
return name.Substring (pos + 1);
pos = name.LastIndexOf ("\\");
if (pos != -1)
return name.Substring (pos + 1);
return name;
}
string TrimExt (string name)
{
int pos = name.LastIndexOf (".");
return name.Substring (0, pos);
}
public string FileName;
public CodeGen (string name, string output, bool want_debugging_support)
{
AssemblyName an;
FileName = output;
an = new AssemblyName ();
an.Name = TrimExt (Basename (name));
current_domain = AppDomain.CurrentDomain;
assembly_builder = current_domain.DefineDynamicAssembly (
an, AssemblyBuilderAccess.RunAndSave);
//
// Pass a path-less name to DefineDynamicModule. Wonder how
// this copes with output in different directories then.
// FIXME: figure out how this copes with --output /tmp/blah
//
// If the third argument is true, the ModuleBuilder will dynamically
// load the default symbol writer.
module_builder = assembly_builder.DefineDynamicModule (
Basename (name), Basename (output), want_debugging_support);
// If we want debugging support, get the default symbol writer
// from the ModuleBuilder, it has already been dynamically loaded
// by the ModuleBuilder's constructor.
if (want_debugging_support)
SymbolWriter = module_builder.GetSymWriter ();
// If we got an ISymbolWriter instance, initialize it.
if (SymbolWriter != null) {
// Due to lacking documentation about the first argument of the
// Initialize method, we cannot use Microsoft's default symbol
// writer yet.
//
// If we're using the mono symbol writer, the SymbolWriter object
// is of type MonoSymbolWriter - but that's defined in a dynamically
// loaded DLL - that's why we're doing a comparision based on the type
// name here instead of using `SymbolWriter is MonoSymbolWriter'.
if (SymbolWriter.GetType ().Name != "MonoSymbolWriter")
Report.Error (16, "Cannot generate debugging information " +
"on this platform");
string symbol_output = an.Name + "-debug.s";
// Mono's default symbol writer ignores the first and third argument
// of this method.
SymbolWriter.Initialize (new IntPtr (0), symbol_output, true);
}
}
public AssemblyBuilder AssemblyBuilder {
get {
return assembly_builder;
}
}
public ModuleBuilder ModuleBuilder {
get {
return module_builder;
}
}
public void Save (string name)
{
try {
assembly_builder.Save (Basename (name));
} catch (System.IO.IOException io){
Report.Error (16, "Coult not write to file `"+name+"', cause: " + io.Message);
}
if (SymbolWriter != null) {
// If we have a symbol writer, call its Close() method to write
// the symbol file to disk.
//
// When using Mono's default symbol writer, the Close() method must
// be called after the assembly has already been written to disk since
// it opens the assembly and reads its metadata.
SymbolWriter.Close ();
}
}
}
///
/// An Emit Context is created for each body of code (from methods,
/// properties bodies, indexer bodies or constructor bodies)
///
public class EmitContext {
public DeclSpace DeclSpace;
public TypeContainer TypeContainer;
public ILGenerator ig;
///
/// This variable tracks the `checked' state of the compilation,
/// it controls whether we should generate code that does overflow
/// checking, or if we generate code that ignores overflows.
///
/// The default setting comes from the command line option to generate
/// checked or unchecked code plus any source code changes using the
/// checked/unchecked statements or expressions. Contrast this with
/// the ConstantCheckState flag.
///
public bool CheckState;
///
/// The constant check state is always set to `true' and cant be changed
/// from the command line. The source code can change this setting with
/// the `checked' and `unchecked' statements and expressions.
///
public bool ConstantCheckState;
///
/// Whether we are emitting code inside a static or instance method
///
public bool IsStatic;
///
/// The value that is allowed to be returned or NULL if there is no
/// return type.
///
public Type ReturnType;
///
/// Points to the Type (extracted from the TypeContainer) that
/// declares this body of code
///
public Type ContainerType;
///
/// Whether this is generating code for a constructor
///
public bool IsConstructor;
///
/// Keeps track of the Type to LocalBuilder temporary storage created
/// to store structures (used to compute the address of the structure
/// value on structure method invocations)
///
public Hashtable temporary_storage;
public Block CurrentBlock;
///
/// The location where we store the return value.
///
LocalBuilder return_value;
///
/// The location where return has to jump to return the
/// value
///
public Label ReturnLabel;
///
/// Whether we are in a Finally block
///
public bool InFinally;
///
/// Whether we are in a Try block
///
public bool InTry;
///
/// Whether we are in a Catch block
///
public bool InCatch;
///
/// Whether we are inside an unsafe block
///
public bool InUnsafe;
///
/// Location for this EmitContext
///
public Location loc;
///
/// Used to "flag" the resolution process to only lookup types,
/// and nothing else. This is an out-of-band communication
/// path to SimpleName from the cast operation.
///
public bool OnlyLookupTypes;
public EmitContext (TypeContainer parent, DeclSpace ds, Location l, ILGenerator ig,
Type return_type, int code_flags, bool is_constructor)
{
this.ig = ig;
TypeContainer = parent;
DeclSpace = ds;
CheckState = RootContext.Checked;
ConstantCheckState = true;
IsStatic = (code_flags & Modifiers.STATIC) != 0;
ReturnType = return_type;
IsConstructor = is_constructor;
CurrentBlock = null;
ContainerType = parent.TypeBuilder;
InUnsafe = ((parent.ModFlags | code_flags) & Modifiers.UNSAFE) != 0;
OnlyLookupTypes = false;
loc = l;
if (ReturnType == TypeManager.void_type)
ReturnType = null;
}
public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
Type return_type, int code_flags, bool is_constructor)
: this (tc, tc, l, ig, return_type, code_flags, is_constructor)
{
}
public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
Type return_type, int code_flags)
: this (tc, tc, l, ig, return_type, code_flags, false)
{
}
public void EmitTopBlock (Block block, Location loc)
{
bool has_ret = false;
// Console.WriteLine ("Emitting: " + loc);
if (block != null){
int errors = Report.Errors;
block.EmitMeta (this, block);
if (Report.Errors == errors){
has_ret = block.Emit (this);
if (Report.Errors == errors){
if (RootContext.WarningLevel >= 3)
block.UsageWarning ();
}
}
}
if (ReturnType != null && !has_ret){
//
// FIXME: we need full flow analysis to implement this
// correctly and emit an error instead of a warning.
//
//
Report.Error (161, loc, "Not all code paths return a value");
return;
}
if (return_value != null){
ig.MarkLabel (ReturnLabel);
ig.Emit (OpCodes.Ldloc, return_value);
ig.Emit (OpCodes.Ret);
} else {
if (!has_ret){
if (!InTry)
ig.Emit (OpCodes.Ret);
}
}
}
///
/// Returns a temporary storage for a variable of type t as
/// a local variable in the current body.
///
public LocalBuilder GetTemporaryStorage (Type t)
{
LocalBuilder location;
if (temporary_storage != null){
location = (LocalBuilder) temporary_storage [t];
if (location != null)
return location;
}
location = ig.DeclareLocal (t);
return location;
}
public void FreeTemporaryStorage (LocalBuilder b)
{
// Empty for now.
}
///
/// Current loop begin and end labels.
///
public Label LoopBegin, LoopEnd;
///
/// Whether we are inside a loop and break/continue are possible.
///
public bool InLoop;
///
/// Default target in a switch statement. Only valid if
/// InSwitch is true
///
public Label DefaultTarget;
///
/// If this is non-null, points to the current switch statement
///
public Switch Switch;
///
/// ReturnValue creates on demand the LocalBuilder for the
/// return value from the function. By default this is not
/// used. This is only required when returns are found inside
/// Try or Catch statements.
///
public LocalBuilder TemporaryReturn ()
{
if (return_value == null){
return_value = ig.DeclareLocal (ReturnType);
ReturnLabel = ig.DefineLabel ();
}
return return_value;
}
///
/// A dynamic This that is shared by all variables in a emitcontext.
/// Created on demand.
///
public Expression my_this;
public Expression This {
get {
if (my_this == null)
my_this = new This (loc).Resolve (this);
return my_this;
}
}
}
}