Initial import.

T0/WordInterpreted.cs

@@ -0,0 +1,283 @@
+/*
+ * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+using System;
+using System.Collections.Generic;
+
+/*
+ * The implementation for interpreted words.
+ */
+
+class WordInterpreted : Word {
+
+	/*
+	 * Get the number of local variables for this word.
+	 */
+	internal int NumLocals {
+		get; private set;
+	}
+
+	/*
+	 * Get the sequence of opcodes for this word.
+	 */
+	internal Opcode[] Code {
+		get; private set;
+	}
+
+	string[] toResolve;
+
+	internal WordInterpreted(T0Comp owner, string name,
+		int numLocals, Opcode[] code, string[] toResolve)
+		: base(owner, name)
+	{
+		this.Code = code;
+		this.toResolve = toResolve;
+		NumLocals = numLocals;
+	}
+
+	internal override void Resolve()
+	{
+		if (toResolve == null) {
+			return;
+		}
+		for (int i = 0; i < toResolve.Length; i ++) {
+			string tt = toResolve[i];
+			if (tt == null) {
+				continue;
+			}
+			Code[i].ResolveTarget(TC.Lookup(tt));
+		}
+		toResolve = null;
+	}
+
+	internal override void Run(CPU cpu)
+	{
+		Resolve();
+		cpu.Enter(Code, NumLocals);
+	}
+
+	internal override List<Word> GetReferences()
+	{
+		Resolve();
+		List<Word> r = new List<Word>();
+		foreach (Opcode op in Code) {
+			Word w = op.GetReference(TC);
+			if (w != null) {
+				r.Add(w);
+			}
+		}
+		return r;
+	}
+
+	internal override List<ConstData> GetDataBlocks()
+	{
+		Resolve();
+		List<ConstData> r = new List<ConstData>();
+		foreach (Opcode op in Code) {
+			ConstData cd = op.GetDataBlock(TC);
+			if (cd != null) {
+				r.Add(cd);
+			}
+		}
+		return r;
+	}
+
+	internal override void GenerateCodeElements(List<CodeElement> dst)
+	{
+		Resolve();
+		int n = Code.Length;
+		CodeElement[] gcode = new CodeElement[n];
+		for (int i = 0; i < n; i ++) {
+			gcode[i] = Code[i].ToCodeElement();
+		}
+		for (int i = 0; i < n; i ++) {
+			Code[i].FixUp(gcode, i);
+		}
+		dst.Add(new CodeElementUInt((uint)NumLocals));
+		for (int i = 0; i < n; i ++) {
+			dst.Add(gcode[i]);
+		}
+	}
+
+	int flowAnalysis;
+	int maxDataStack;
+	int maxReturnStack;
+
+	bool MergeSA(int[] sa, int j, int c)
+	{
+		if (sa[j] == Int32.MinValue) {
+			sa[j] = c;
+			return true;
+		} else if (sa[j] != c) {
+			throw new Exception(string.Format(
+				"In word '{0}', offset {1}:"
+				+ " stack action mismatch ({2} / {3})",
+				Name, j, sa[j], c));
+		} else {
+			return false;
+		}
+	}
+
+	internal override void AnalyseFlow()
+	{
+		switch (flowAnalysis) {
+		case 0:
+			break;
+		case 1:
+			return;
+		default:
+			throw new Exception("recursive call detected in '"
+				+ Name + "'");
+		}
+		flowAnalysis = 2;
+		int n = Code.Length;
+		int[] sa = new int[n];
+		for (int i = 0; i < n; i ++) {
+			sa[i] = Int32.MinValue;
+		}
+		sa[0] = 0;
+		int[] toExplore = new int[n];
+		int tX = 0, tY = 0;
+		int off = 0;
+
+		int exitSA = Int32.MinValue;
+		int mds = 0;
+		int mrs = 0;
+
+		int maxDepth = 0;
+
+		for (;;) {
+			Opcode op = Code[off];
+			bool mft = op.MayFallThrough;
+			int c = sa[off];
+			int a;
+			if (op is OpcodeCall) {
+				Word w = op.GetReference(TC);
+				w.AnalyseFlow();
+				SType se = w.StackEffect;
+				if (!se.IsKnown) {
+					throw new Exception(string.Format(
+						"call from '{0}' to '{1}'"
+						+ " with unknown stack effect",
+						Name, w.Name));
+				}
+				if (se.NoExit) {
+					mft = false;
+					a = 0;
+				} else {
+					a = se.DataOut - se.DataIn;
+				}
+				mds = Math.Max(mds, c + w.MaxDataStack);
+				mrs = Math.Max(mrs, w.MaxReturnStack);
+				maxDepth = Math.Min(maxDepth, c - se.DataIn);
+			} else if (op is OpcodeRet) {
+				if (exitSA == Int32.MinValue) {
+					exitSA = c;
+				} else if (exitSA != c) {
+					throw new Exception(string.Format(
+						"'{0}': exit stack action"
+						+ " mismatch: {1} / {2}"
+						+ " (offset {3})",
+						Name, exitSA, c, off));
+				}
+				a = 0;
+			} else {
+				a = op.StackAction;
+				mds = Math.Max(mds, c + a);
+			}
+			c += a;
+			maxDepth = Math.Min(maxDepth, c);
+
+			int j = op.JumpDisp;
+			if (j != 0) {
+				j += off + 1;
+				toExplore[tY ++] = j;
+				MergeSA(sa, j, c);
+			}
+			off ++;
+			if (!mft || !MergeSA(sa, off, c)) {
+				if (tX < tY) {
+					off = toExplore[tX ++];
+				} else {
+					break;
+				}
+			}
+		}
+
+		maxDataStack = mds;
+		maxReturnStack = 1 + NumLocals + mrs;
+
+		/*
+		 * TODO: see about this warning. Usage of a 'fail'
+		 * word (that does not exit) within a 'case..endcase'
+		 * structure will make an unreachable opcode. In a future
+		 * version we might want to automatically remove dead
+		 * opcodes.
+		for (int i = 0; i < n; i ++) {
+			if (sa[i] == Int32.MinValue) {
+				Console.WriteLine("warning: word '{0}',"
+					+ " offset {1}: unreachable opcode",
+					Name, i);
+				continue;
+			}
+		}
+		 */
+
+		SType computed;
+		if (exitSA == Int32.MinValue) {
+			computed = new SType(-maxDepth, -1);
+		} else {
+			computed = new SType(-maxDepth, -maxDepth + exitSA);
+		}
+
+		if (StackEffect.IsKnown) {
+			if (!computed.IsSubOf(StackEffect)) {
+				throw new Exception(string.Format(
+					"word '{0}':"
+					+ " computed stack effect {1}"
+					+ " does not match declared {2}",
+					Name, computed.ToString(),
+					StackEffect.ToString()));
+			}
+		} else {
+			StackEffect = computed;
+		}
+
+		flowAnalysis = 1;
+	}
+
+	internal override int MaxDataStack {
+		get {
+			AnalyseFlow();
+			return maxDataStack;
+		}
+	}
+
+	internal override int MaxReturnStack {
+		get {
+			AnalyseFlow();
+			return maxReturnStack;
+		}
+	}
+}