2 // codegen.cs: The code generator
5 // Miguel de Icaza (miguel@ximian.com)
7 // (C) 2001 Ximian, Inc.
12 using System.Collections;
13 using System.Reflection;
14 using System.Reflection.Emit;
16 namespace Mono.CSharp {
19 /// Code generator class.
21 public class CodeGen {
22 static AppDomain current_domain;
23 public static AssemblyBuilder AssemblyBuilder;
24 public static ModuleBuilder ModuleBuilder;
26 static public SymbolWriter SymbolWriter;
28 public static string Basename (string name)
30 int pos = name.LastIndexOf ('/');
33 return name.Substring (pos + 1);
35 pos = name.LastIndexOf ('\\');
37 return name.Substring (pos + 1);
42 public static string Dirname (string name)
44 int pos = name.LastIndexOf ('/');
47 return name.Substring (0, pos);
49 pos = name.LastIndexOf ('\\');
51 return name.Substring (0, pos);
56 static string TrimExt (string name)
58 int pos = name.LastIndexOf ('.');
60 return name.Substring (0, pos);
63 static public string FileName;
66 // Initializes the symbol writer
68 static void InitializeSymbolWriter ()
70 SymbolWriter = SymbolWriter.GetSymbolWriter (ModuleBuilder);
73 // If we got an ISymbolWriter instance, initialize it.
75 if (SymbolWriter == null) {
77 -18, "Could not find the symbol writer assembly (Mono.CSharp.Debugger.dll). This is normally an installation problem. Please make sure to compile and install the mcs/class/Mono.CSharp.Debugger directory.");
83 // Initializes the code generator variables
85 static public void Init (string name, string output, bool want_debugging_support)
90 an = new AssemblyName ();
91 an.Name = Path.GetFileNameWithoutExtension (name);
93 current_domain = AppDomain.CurrentDomain;
94 AssemblyBuilder = current_domain.DefineDynamicAssembly (
95 an, AssemblyBuilderAccess.Save, Dirname (name));
98 // Pass a path-less name to DefineDynamicModule. Wonder how
99 // this copes with output in different directories then.
100 // FIXME: figure out how this copes with --output /tmp/blah
102 // If the third argument is true, the ModuleBuilder will dynamically
103 // load the default symbol writer.
105 ModuleBuilder = AssemblyBuilder.DefineDynamicModule (
106 Basename (name), Basename (output), want_debugging_support);
108 if (want_debugging_support)
109 InitializeSymbolWriter ();
112 static public void Save (string name)
115 AssemblyBuilder.Save (Basename (name));
116 } catch (System.IO.IOException io){
117 Report.Error (16, "Could not write to file `"+name+"', cause: " + io.Message);
123 // Provides "local" store across code that can yield: locals
124 // or fields, notice that this should not be used by anonymous
125 // methods to create local storage, those only require
128 public class VariableStorage {
135 public VariableStorage (EmitContext ec, Type t)
139 fb = IteratorHandler.Current.MapVariable ("s_", count.ToString (), t);
141 local = ec.ig.DeclareLocal (t);
145 public void EmitThis ()
148 ig.Emit (OpCodes.Ldarg_0);
151 public void EmitStore ()
154 ig.Emit (OpCodes.Stloc, local);
156 ig.Emit (OpCodes.Stfld, fb);
159 public void EmitLoad ()
162 ig.Emit (OpCodes.Ldloc, local);
164 ig.Emit (OpCodes.Ldfld, fb);
169 /// An Emit Context is created for each body of code (from methods,
170 /// properties bodies, indexer bodies or constructor bodies)
172 public class EmitContext {
173 public DeclSpace DeclSpace;
174 public DeclSpace TypeContainer;
175 public ILGenerator ig;
178 /// This variable tracks the `checked' state of the compilation,
179 /// it controls whether we should generate code that does overflow
180 /// checking, or if we generate code that ignores overflows.
182 /// The default setting comes from the command line option to generate
183 /// checked or unchecked code plus any source code changes using the
184 /// checked/unchecked statements or expressions. Contrast this with
185 /// the ConstantCheckState flag.
188 public bool CheckState;
191 /// The constant check state is always set to `true' and cant be changed
192 /// from the command line. The source code can change this setting with
193 /// the `checked' and `unchecked' statements and expressions.
195 public bool ConstantCheckState;
198 /// Whether we are emitting code inside a static or instance method
200 public bool IsStatic;
203 /// Whether we are emitting a field initializer
205 public bool IsFieldInitializer;
208 /// The value that is allowed to be returned or NULL if there is no
211 public Type ReturnType;
214 /// Points to the Type (extracted from the TypeContainer) that
215 /// declares this body of code
217 public Type ContainerType;
220 /// Whether this is generating code for a constructor
222 public bool IsConstructor;
225 /// Whether we're control flow analysis enabled
227 public bool DoFlowAnalysis;
230 /// Keeps track of the Type to LocalBuilder temporary storage created
231 /// to store structures (used to compute the address of the structure
232 /// value on structure method invocations)
234 public Hashtable temporary_storage;
236 public Block CurrentBlock;
238 public int CurrentFile;
241 /// The location where we store the return value.
243 LocalBuilder return_value;
246 /// The location where return has to jump to return the
249 public Label ReturnLabel;
252 /// If we already defined the ReturnLabel
254 public bool HasReturnLabel;
257 /// Whether we are inside an iterator block.
259 public bool InIterator;
261 public bool IsLastStatement;
264 /// Whether remapping of locals, parameters and fields is turned on.
265 /// Used by iterators and anonymous methods.
267 public bool RemapToProxy;
270 /// Whether we are inside an unsafe block
272 public bool InUnsafe;
275 /// Whether we are in a `fixed' initialization
277 public bool InFixedInitializer;
280 /// Whether we are inside an anonymous method.
282 public bool InAnonymousMethod;
285 /// Location for this EmitContext
290 /// Used to flag that it is ok to define types recursively, as the
291 /// expressions are being evaluated as part of the type lookup
292 /// during the type resolution process
294 public bool ResolvingTypeTree;
297 /// Inside an enum definition, we do not resolve enumeration values
298 /// to their enumerations, but rather to the underlying type/value
299 /// This is so EnumVal + EnumValB can be evaluated.
301 /// There is no "E operator + (E x, E y)", so during an enum evaluation
302 /// we relax the rules
304 public bool InEnumContext;
306 FlowBranching current_flow_branching;
308 public EmitContext (DeclSpace parent, DeclSpace ds, Location l, ILGenerator ig,
309 Type return_type, int code_flags, bool is_constructor)
313 TypeContainer = parent;
315 CheckState = RootContext.Checked;
316 ConstantCheckState = true;
318 IsStatic = (code_flags & Modifiers.STATIC) != 0;
319 InIterator = (code_flags & Modifiers.METHOD_YIELDS) != 0;
320 RemapToProxy = InIterator;
321 ReturnType = return_type;
322 IsConstructor = is_constructor;
327 // Can only be null for the ResolveType contexts.
328 ContainerType = parent.TypeBuilder;
329 if (parent.UnsafeContext)
332 InUnsafe = (code_flags & Modifiers.UNSAFE) != 0;
336 if (ReturnType == TypeManager.void_type)
340 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
341 Type return_type, int code_flags, bool is_constructor)
342 : this (tc, tc, l, ig, return_type, code_flags, is_constructor)
346 public EmitContext (TypeContainer tc, Location l, ILGenerator ig,
347 Type return_type, int code_flags)
348 : this (tc, tc, l, ig, return_type, code_flags, false)
352 public FlowBranching CurrentBranching {
354 return current_flow_branching;
359 // Starts a new code branching. This inherits the state of all local
360 // variables and parameters from the current branching.
362 public FlowBranching StartFlowBranching (FlowBranching.BranchingType type, Location loc)
364 current_flow_branching = FlowBranching.CreateBranching (CurrentBranching, type, null, loc);
365 return current_flow_branching;
369 // Starts a new code branching for block `block'.
371 public FlowBranching StartFlowBranching (Block block)
373 FlowBranching.BranchingType type;
375 if (CurrentBranching.Type == FlowBranching.BranchingType.Switch)
376 type = FlowBranching.BranchingType.SwitchSection;
378 type = FlowBranching.BranchingType.Block;
380 current_flow_branching = FlowBranching.CreateBranching (CurrentBranching, type, block, block.StartLocation);
381 return current_flow_branching;
385 // Ends a code branching. Merges the state of locals and parameters
386 // from all the children of the ending branching.
388 public FlowBranching.UsageVector DoEndFlowBranching ()
390 FlowBranching old = current_flow_branching;
391 current_flow_branching = current_flow_branching.Parent;
393 return current_flow_branching.MergeChild (old);
397 // Ends a code branching. Merges the state of locals and parameters
398 // from all the children of the ending branching.
400 public FlowBranching.Reachability EndFlowBranching ()
402 FlowBranching.UsageVector vector = DoEndFlowBranching ();
404 return vector.Reachability;
408 // Kills the current code branching. This throws away any changed state
409 // information and should only be used in case of an error.
411 public void KillFlowBranching ()
413 current_flow_branching = current_flow_branching.Parent;
416 public void EmitTopBlock (Block block, InternalParameters ip, Location loc)
418 bool unreachable = false;
420 if (!Location.IsNull (loc))
421 CurrentFile = loc.File;
425 int errors = Report.Errors;
427 block.EmitMeta (this, ip);
429 if (Report.Errors == errors){
430 bool old_do_flow_analysis = DoFlowAnalysis;
431 DoFlowAnalysis = true;
433 current_flow_branching = FlowBranching.CreateBranching (
434 null, FlowBranching.BranchingType.Block, block, loc);
436 if (!block.Resolve (this)) {
437 current_flow_branching = null;
438 DoFlowAnalysis = old_do_flow_analysis;
442 FlowBranching.Reachability reachability = current_flow_branching.MergeTopBlock ();
443 current_flow_branching = null;
445 DoFlowAnalysis = old_do_flow_analysis;
449 if (reachability.AlwaysReturns ||
450 reachability.AlwaysThrows ||
451 reachability.IsUnreachable)
454 } catch (Exception e) {
455 Console.WriteLine ("Exception caught by the compiler while compiling:");
456 Console.WriteLine (" Block that caused the problem begin at: " + loc);
458 if (CurrentBlock != null){
459 Console.WriteLine (" Block being compiled: [{0},{1}]",
460 CurrentBlock.StartLocation, CurrentBlock.EndLocation);
462 Console.WriteLine (e.GetType ().FullName + ": " + e.Message);
463 Console.WriteLine (Report.FriendlyStackTrace (e));
465 Environment.Exit (1);
469 if (ReturnType != null && !unreachable){
471 Report.Error (161, loc, "Not all code paths return a value");
477 ig.MarkLabel (ReturnLabel);
478 if (return_value != null){
479 ig.Emit (OpCodes.Ldloc, return_value);
480 ig.Emit (OpCodes.Ret);
483 // If `HasReturnLabel' is set, then we already emitted a
484 // jump to the end of the method, so we must emit a `ret'
487 // Unfortunately, System.Reflection.Emit automatically emits
488 // a leave to the end of a finally block. This is a problem
489 // if no code is following the try/finally block since we may
490 // jump to a point after the end of the method.
491 // As a workaround, we're always creating a return label in
495 if ((block != null) && block.IsDestructor) {
496 // Nothing to do; S.R.E automatically emits a leave.
497 } else if (HasReturnLabel || (!unreachable && !InIterator)) {
498 if (ReturnType != null)
499 ig.Emit (OpCodes.Ldloc, TemporaryReturn ());
500 ig.Emit (OpCodes.Ret);
506 /// This is called immediately before emitting an IL opcode to tell the symbol
507 /// writer to which source line this opcode belongs.
509 public void Mark (Location loc, bool check_file)
511 if ((CodeGen.SymbolWriter == null) || Location.IsNull (loc))
514 if (check_file && (CurrentFile != loc.File))
517 ig.MarkSequencePoint (null, loc.Row, 0, 0, 0);
521 /// Returns a temporary storage for a variable of type t as
522 /// a local variable in the current body.
524 public LocalBuilder GetTemporaryLocal (Type t)
526 LocalBuilder location = null;
528 if (temporary_storage != null){
529 object o = temporary_storage [t];
532 ArrayList al = (ArrayList) o;
534 for (int i = 0; i < al.Count; i++){
536 location = (LocalBuilder) al [i];
542 location = (LocalBuilder) o;
543 if (location != null)
548 return ig.DeclareLocal (t);
551 public void FreeTemporaryLocal (LocalBuilder b, Type t)
553 if (temporary_storage == null){
554 temporary_storage = new Hashtable ();
555 temporary_storage [t] = b;
558 object o = temporary_storage [t];
560 temporary_storage [t] = b;
564 ArrayList al = (ArrayList) o;
565 for (int i = 0; i < al.Count; i++){
574 ArrayList replacement = new ArrayList ();
576 temporary_storage.Remove (t);
577 temporary_storage [t] = replacement;
581 /// Current loop begin and end labels.
583 public Label LoopBegin, LoopEnd;
586 /// Default target in a switch statement. Only valid if
589 public Label DefaultTarget;
592 /// If this is non-null, points to the current switch statement
594 public Switch Switch;
597 /// ReturnValue creates on demand the LocalBuilder for the
598 /// return value from the function. By default this is not
599 /// used. This is only required when returns are found inside
600 /// Try or Catch statements.
602 public LocalBuilder TemporaryReturn ()
604 if (return_value == null){
605 return_value = ig.DeclareLocal (ReturnType);
606 ReturnLabel = ig.DefineLabel ();
607 HasReturnLabel = true;
613 public void NeedReturnLabel ()
615 if (!HasReturnLabel) {
616 ReturnLabel = ig.DefineLabel ();
617 HasReturnLabel = true;
622 // Creates a field `name' with the type `t' on the proxy class
624 public FieldBuilder MapVariable (string name, Type t)
627 return IteratorHandler.Current.MapVariable ("v_", name, t);
630 throw new Exception ("MapVariable for an unknown state");
634 // Invoke this routine to remap a VariableInfo into the
635 // proper MemberAccess expression
637 public Expression RemapLocal (LocalInfo local_info)
639 FieldExpr fe = new FieldExpr (local_info.FieldBuilder, loc);
640 fe.InstanceExpression = new ProxyInstance ();
641 return fe.DoResolve (this);
644 public Expression RemapLocalLValue (LocalInfo local_info, Expression right_side)
646 FieldExpr fe = new FieldExpr (local_info.FieldBuilder, loc);
647 fe.InstanceExpression = new ProxyInstance ();
648 return fe.DoResolveLValue (this, right_side);
651 public Expression RemapParameter (int idx)
653 FieldExpr fe = new FieldExprNoAddress (IteratorHandler.Current.parameter_fields [idx], loc);
654 fe.InstanceExpression = new ProxyInstance ();
655 return fe.DoResolve (this);
658 public Expression RemapParameterLValue (int idx, Expression right_side)
660 FieldExpr fe = new FieldExprNoAddress (IteratorHandler.Current.parameter_fields [idx], loc);
661 fe.InstanceExpression = new ProxyInstance ();
662 return fe.DoResolveLValue (this, right_side);
666 // Emits the proper object to address fields on a remapped
667 // variable/parameter to field in anonymous-method/iterator proxy classes.
669 public void EmitThis ()
671 ig.Emit (OpCodes.Ldarg_0);
675 ig.Emit (OpCodes.Ldfld, IteratorHandler.Current.this_field);
677 throw new Exception ("EmitThis for an unknown state");
681 public Expression GetThis (Location loc)
684 if (CurrentBlock != null)
685 my_this = new This (CurrentBlock, loc);
687 my_this = new This (loc);
689 if (!my_this.ResolveBase (this))