mirror of
https://github.com/fadden/6502bench.git
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d3670c48e8
Correct handling of local variables. We now correctly uniquify them with regard to non-unique labels. Because local vars can effectively have global scope we mostly want to treat them as global, but they're uniquified relative to other globals very late in the process, so we can't just throw them in the symbol table and be done. Fortunately local variables exist in a separate namespace, so we just need to uniquify the variables relative to the post-localization symbol table. In other words, we take the symbol table, apply the label map, and rename any variable that clashes. This also fixes an older problem where we weren't masking the leading '_' on variable labels when generating 64tass output. The code list now makes non-unique labels obvious, but you can't tell the difference between unique global and unique local. What's more, the default type value in Edit Label is now adjusted to Global for unique locals that were auto-generated. To make it a bit easier to figure out what's what, the Info panel now has a "label type" line that reports the type. The 2023-non-unique-labels test had some additional tests added to exercise conflicts with local variables. The 2019-local-variables test output changed slightly because the de-duplicated variable naming convention was simplified.
450 lines
20 KiB
C#
450 lines
20 KiB
C#
/*
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* Copyright 2019 faddenSoft
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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namespace SourceGen {
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/// <summary>
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/// Given a list of LocalVariableTables, this determines the mapping of values to symbols
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/// at a specific offset.
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/// </summary>
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/// <remarks>
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/// We guarantee that the label will be unique within its scope. This happens at two
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/// different levels:
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/// (1) If the local variable label is present in the main symbol table, we use the
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/// "de-duplication" table to remap it. We try not to let this happen, but it can.
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/// The symbol table is latched when the object is constructed.
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/// (2) If the assembler doesn't define a way to re-use variable names, we make them
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/// globally unique. [currently not needed]
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/// </remarks>
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public class LocalVariableLookup {
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/// <summary>
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/// List of tables. The table's file offset is used as the key.
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/// </summary>
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private SortedList<int, LocalVariableTable> mLvTables;
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/// <summary>
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/// Reference to project, so we can query the Anattrib array to identify "hidden" tables.
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/// </summary>
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private DisasmProject mProject;
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/// <summary>
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/// Set to true when generating symbols for assemblers like 64tass, which assign a
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/// special meaning to labels with leading underscores.
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/// </summary>
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private bool mMaskLeadingUnderscores;
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/// <summary>
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/// Set to true if we want all variables to be globally unique (because the assembler
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/// can't redefine them).
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/// </summary>
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private bool mDoUniquify;
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/// <summary>
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/// List of all non-variable symbols, for uniquification. This is generated from the
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/// project symbol table. When generating assembly sources, the labels are transformed
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/// through the label map.
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/// </summary>
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private Dictionary<string, Symbol> mAllNvSymbols;
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/// <summary>
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/// Label uniquification helper.
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///
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/// The BaseLabel does not change, but Label is updated by MakeUnique.
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/// </summary>
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/// <remarks>
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/// LvLookup is run multiple times, and can be restarted in the middle of a run. It's
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/// essential that UniqueLabel behaves deterministically. For this to happen, the
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/// contents of SymbolTable can't change in a way that affects the outcome unless it
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/// also causes us to redo the uniquification. This mostly means that we have to be
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/// very careful about creating duplicate symbols, so that we don't get halfway through
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/// the analysis pass and invalidate our previous work. It's best to leave
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/// uniquification disabled until we're generating assembly source code.
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///
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/// The issues also make it hard to do the uniquification once, rather than every time we
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/// walk the code. Not all symbol changes cause a re-analysis (e.g. renaming a user
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/// label does not), and we don't want to fill the symbol table with the uniquified
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/// names because it could block user labels that would otherwise be valid.
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/// </remarks>
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private class UniqueLabel {
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public string BaseLabel { get; private set; }
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public string Label { get; private set; }
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private int Counter { get; set; }
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public UniqueLabel(string baseLabel) {
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Label = BaseLabel = baseLabel;
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Counter = 0;
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}
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/// <summary>
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/// Updates the Label to be unique. Call this when a symbol is defined or
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/// re-defined.
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/// </summary>
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/// <param name="symbolTable">Symbol table, for uniqueness check.</param>
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public void MakeUnique(Dictionary<string, Symbol> allNvSymbols) {
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// The main symbol table might have user-supplied labels like "ptr_2", so we
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// need to keep testing against that. However, it should not be possible for
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// us to clash with other uniquified variables. So we don't need to check
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// for clashes in the UniqueLabel list.
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//
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// It *is* possible to clash with other variable base names, so we can't
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// exclude variables from our SymbolTable lookup.
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string testLabel;
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do {
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Counter++;
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testLabel = BaseLabel + "_" + Counter;
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} while (allNvSymbols.TryGetValue(testLabel, out Symbol unused));
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Label = testLabel;
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}
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}
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private Dictionary<string, UniqueLabel> mUniqueLabels;
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/// <summary>
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/// Duplicate label re-map. This is applied before uniquification.
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/// </summary>
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/// <remarks>
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/// It's hard to do this as part of uniquification because the remapped base name ends
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/// up in the symbol table, and the uniquifier isn't able to tell that the entry in the
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/// symbol table is itself. The logic is simpler if we just rename the label before
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/// the uniquifier ever sees it.
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///
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/// I feel like there has to be a simpler way to do this. This'll do for now.
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/// </remarks>
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private Dictionary<string, string> mDupRemap;
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/// <summary>
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/// Most recently processed offset.
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/// </summary>
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private int mRecentOffset;
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/// <summary>
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/// Symbols defined at mRecentOffset.
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/// </summary>
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private List<DefSymbol> mRecentSymbols;
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/// <summary>
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/// Cumulative symbols defined at the current offset.
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/// </summary>
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private LocalVariableTable mCurrentTable;
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// Next point of interest.
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private int mNextLvtIndex;
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private int mNextLvtOffset;
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/// <summary>
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/// Constructor.
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/// </summary>
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/// <param name="lvTables">List of tables from the DisasmProject.</param>
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/// <param name="project">Project reference.</param>
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/// <param name="labelMap">Label map dictionary, used to rename the labels in
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/// the project symbol table. May be null.</param>
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/// <param name="maskLeadingUnderscores">If true, labels with leading underscores
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/// will be prefixed.</param>
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/// <param name="uniquify">Set to true if variable names cannot be redefined.</param>
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public LocalVariableLookup(SortedList<int, LocalVariableTable> lvTables,
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DisasmProject project, Dictionary<string, string> labelMap,
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bool maskLeadingUnderscores, bool uniquify) {
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mLvTables = lvTables;
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mProject = project;
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mMaskLeadingUnderscores = maskLeadingUnderscores;
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mDoUniquify = uniquify;
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mCurrentTable = new LocalVariableTable();
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mDupRemap = new Dictionary<string, string>();
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if (uniquify) {
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mUniqueLabels = new Dictionary<string, UniqueLabel>();
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}
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CreateAllSymbolsDict(labelMap);
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Reset();
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}
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private void CreateAllSymbolsDict(Dictionary<string, string> labelMap) {
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SymbolTable symTab = mProject.SymbolTable;
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mAllNvSymbols = new Dictionary<string, Symbol>(symTab.Count);
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foreach (Symbol sym in symTab) {
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if (sym.SymbolSource == Symbol.Source.Variable) {
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continue;
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}
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if (labelMap != null && labelMap.TryGetValue(sym.Label, out string newLabel)) {
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// Non-unique labels may map multiple entries to a single entry. That's
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// fine; our goal here is just to avoid duplication. Besides, any symbols
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// being output as locals will have the local prefix character and won't
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// be a match.
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mAllNvSymbols[newLabel] = sym;
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} else {
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mAllNvSymbols[sym.Label] = sym;
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}
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}
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}
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public void Reset() {
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mRecentOffset = -1;
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mRecentSymbols = null;
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mCurrentTable.Clear();
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mUniqueLabels?.Clear();
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mDupRemap.Clear();
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if (mLvTables.Count == 0) {
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mNextLvtIndex = -1;
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mNextLvtOffset = mProject.FileDataLength;
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} else {
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mNextLvtIndex = 0;
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mNextLvtOffset = mLvTables.Keys[0];
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}
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}
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/// <summary>
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/// Gets the symbol associated with the operand of an instruction.
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/// </summary>
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/// <param name="offset">Offset of start of instruction.</param>
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/// <param name="operandValue">Operand value.</param>
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/// <param name="type">Operand type. Should be ExternalAddress for DP ops, or
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/// Constant for StackRel ops.</param>
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/// <returns>Symbol, or null if no match found.</returns>
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public DefSymbol GetSymbol(int offset, int operandValue, Symbol.Type type) {
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AdvanceToOffset(offset);
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return mCurrentTable.GetByValueRange(operandValue, 1, type);
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}
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/// <summary>
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/// Gets the symbol associated with a symbol reference. If uniquification is enabled,
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/// the unique-label map for the specified offset will be used to transform the
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/// symbol reference.
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/// </summary>
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/// <param name="offset">Offset of start of instruction.</param>
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/// <param name="symRef">Reference to symbol.</param>
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/// <returns>Symbol, or null if no match found.</returns>
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public DefSymbol GetSymbol(int offset, WeakSymbolRef symRef) {
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AdvanceToOffset(offset);
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// The symRef uses the non-uniquified symbol, so we need to get the unique value at
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// the current offset. We may need to do this even when variables can be
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// redefined, because we might have a variable that's a duplicate of a user label
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// or project symbol.
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// Start by applying the de-duplication map.
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string label = symRef.Label;
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if (mDupRemap.TryGetValue(symRef.Label, out string remap)) {
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label = remap;
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}
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//Debug.WriteLine("GetSymbol " + symRef.Label + " -> " + label);
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if (mUniqueLabels != null && mUniqueLabels.TryGetValue(label, out UniqueLabel ulab)) {
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//Debug.WriteLine(" Unique var " + symRef.Label + " -> " + ulab.Label);
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label = ulab.Label;
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}
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DefSymbol defSym = mCurrentTable.GetByLabel(label);
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// In theory this is okay, but in practice the only things asking for symbols are
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// entirely convinced that the symbol exists here. So this is probably a bug.
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Debug.Assert(defSym != null);
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return defSym;
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}
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/// <summary>
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/// Identifies the LocalVariableTable that defined the symbol reference.
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/// </summary>
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/// <param name="offset">Offset at which the symbol was referenced.</param>
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/// <param name="symRef">Reference to symbol.</param>
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/// <returns>Table index, or -1 if not found.</returns>
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public int GetDefiningTableOffset(int offset, WeakSymbolRef symRef) {
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// symRef is the non-uniquified, non-de-duplicated symbol that was generated
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// during the analysis pass. This matches the contents of the tables, so we don't
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// need to transform it at all.
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//
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// Walk backward through the list of tables until we find a match.
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IList<int> keys = mLvTables.Keys;
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for (int i = keys.Count - 1; i >= 0; i--) {
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if (keys[i] > offset) {
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// table comes after the point of reference
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continue;
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}
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if (mLvTables.Values[i].GetByLabel(symRef.Label) != null) {
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// found it
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return keys[i];
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}
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}
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// if we didn't find it, it doesn't exist... right?
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Debug.Assert(mCurrentTable.GetByLabel(symRef.Label) == null);
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return -1;
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}
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/// <summary>
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/// Gets a LocalVariableTable that is the result of merging all tables up to this point.
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/// </summary>
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/// <param name="offset">Target offset.</param>
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/// <returns>Combined table.</returns>
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public LocalVariableTable GetMergedTableAtOffset(int offset) {
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AdvanceToOffset(offset);
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return mCurrentTable;
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}
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/// <summary>
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/// Finds the closest table that is defined at or before the specified offset. Will
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/// attempt to only return un-hidden tables, but will return a hidden table if no
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/// others are available.
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/// </summary>
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/// <param name="offset">Target offset.</param>
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/// <returns>The table's definition offset, or -1 if no tables were defined before this
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/// point.</returns>
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public int GetNearestTableOffset(int offset) {
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int nearest = -1;
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int nearestUnhidden = -1;
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// Could do a smarter search, but I'm expecting the set to be small.
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foreach (KeyValuePair<int, LocalVariableTable> kvp in mLvTables) {
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if (kvp.Key > offset) {
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break;
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}
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nearest = kvp.Key;
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if (mProject.GetAnattrib(nearest).IsStart) {
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nearestUnhidden = nearest;
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}
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}
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if (nearestUnhidden >= 0) {
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return nearestUnhidden;
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} else {
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return nearest;
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}
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}
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/// <summary>
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/// Generates a list of variables defined at the specified offset, if a table is
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/// associated with that offset.
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/// </summary>
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/// <param name="offset">File data offset.</param>
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/// <returns>List of symbols, uniquified if desired, or null if no LocalVariableTable
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/// exists at the specified offset.</returns>
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public List<DefSymbol> GetVariablesDefinedAtOffset(int offset) {
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AdvanceToOffset(offset);
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if (mRecentOffset == offset) {
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return mRecentSymbols;
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}
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return null;
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}
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/// <summary>
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/// Updates internal state to reflect the state of the world at the specified offset.
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/// </summary>
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/// <remarks>
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/// When the offset is greater than or equal to its value on a previous call, we can
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/// do an incremental update. If the offset moves backward, we have to reset and walk
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/// forward again.
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/// </remarks>
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/// <param name="targetOffset">Target offset.</param>
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private void AdvanceToOffset(int targetOffset) {
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if (mNextLvtIndex < 0) {
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return;
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}
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if (targetOffset < mRecentOffset) {
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// We went backwards.
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Reset();
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}
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while (mNextLvtOffset <= targetOffset) {
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if (!mProject.GetAnattrib(mNextLvtOffset).IsStart) {
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// Hidden table, ignore it.
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Debug.WriteLine("Ignoring LvTable at +" + mNextLvtOffset.ToString("x6"));
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} else {
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// Process this table.
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LocalVariableTable lvt = mLvTables.Values[mNextLvtIndex];
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if (lvt.ClearPrevious) {
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mCurrentTable.Clear();
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}
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// Create a list for GetVariablesDefinedAtOffset
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mRecentSymbols = new List<DefSymbol>();
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mRecentOffset = mNextLvtOffset;
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// Merge the new entries into the work table. This automatically
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// discards entries that clash by name or value.
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for (int i = 0; i < lvt.Count; i++) {
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DefSymbol defSym = lvt[i];
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string newLabel = defSym.Label;
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if (mMaskLeadingUnderscores && newLabel[0] == '_') {
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newLabel = AsmGen.LabelLocalizer.NO_UNDER_PFX + newLabel;
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}
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// Look for non-variable symbols with the same label. Ordinarily the
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// editor prevents this from happening, but there are ways to trick
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// the system (e.g. add a symbol while the LvTable is hidden, or have
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// a non-unique local promoted to global). We deal with it here.
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//
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// TODO(someday): this is not necessary for assemblers like Merlin 32
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// that put variables in a separate namespace.
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if (mAllNvSymbols.TryGetValue(newLabel, out Symbol unused)) {
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Debug.WriteLine("Detected duplicate non-var label " + newLabel +
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" at +" + mNextLvtOffset.ToString("x6"));
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newLabel = DeDupLabel(newLabel);
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}
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if (newLabel != defSym.Label) {
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mDupRemap[defSym.Label] = newLabel;
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defSym = new DefSymbol(defSym, newLabel);
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}
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if (mDoUniquify) {
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if (mUniqueLabels.TryGetValue(defSym.Label, out UniqueLabel ulab)) {
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// We've seen this label before; generate a unique version by
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// increasing the appended number.
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ulab.MakeUnique(mAllNvSymbols);
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defSym = new DefSymbol(defSym, ulab.Label);
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} else {
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// Haven't seen this before. Add it to the unique-labels table.
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mUniqueLabels.Add(defSym.Label, new UniqueLabel(defSym.Label));
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}
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}
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mCurrentTable.AddOrReplace(defSym);
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mRecentSymbols.Add(defSym);
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}
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//mCurrentTable.DebugDump(mNextLvtOffset);
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}
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// Update state to look for next table.
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mNextLvtIndex++;
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if (mNextLvtIndex < mLvTables.Keys.Count) {
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mNextLvtOffset = mLvTables.Keys[mNextLvtIndex];
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} else {
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mNextLvtOffset = mProject.FileDataLength; // never reached
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}
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}
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}
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/// <summary>
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/// Generates a unique label for the duplicate remap table.
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/// </summary>
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private string DeDupLabel(string baseLabel) {
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string testLabel;
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int counter = 0;
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do {
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counter++;
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testLabel = baseLabel + "_" + counter;
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} while (mAllNvSymbols.TryGetValue(testLabel, out Symbol unused));
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return testLabel;
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}
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public static bool IsTableHidden(int offset, DisasmProject project) {
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return !project.GetAnattrib(offset).IsStart;
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}
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}
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}
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