summaryrefslogtreecommitdiffstats
path: root/gfx/angle/src/compiler/translator/RemoveDynamicIndexing.cpp
blob: 37955e7360b98e4113b36e0ec107fa0a42031a5e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
//
// Copyright (c) 2002-2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// RemoveDynamicIndexing is an AST traverser to remove dynamic indexing of vectors and matrices,
// replacing them with calls to functions that choose which component to return or write.
//

#include "compiler/translator/RemoveDynamicIndexing.h"

#include "compiler/translator/InfoSink.h"
#include "compiler/translator/IntermNode.h"
#include "compiler/translator/IntermNodePatternMatcher.h"
#include "compiler/translator/SymbolTable.h"

namespace
{

TName GetIndexFunctionName(const TType &type, bool write)
{
    TInfoSinkBase nameSink;
    nameSink << "dyn_index_";
    if (write)
    {
        nameSink << "write_";
    }
    if (type.isMatrix())
    {
        nameSink << "mat" << type.getCols() << "x" << type.getRows();
    }
    else
    {
        switch (type.getBasicType())
        {
            case EbtInt:
                nameSink << "ivec";
                break;
            case EbtBool:
                nameSink << "bvec";
                break;
            case EbtUInt:
                nameSink << "uvec";
                break;
            case EbtFloat:
                nameSink << "vec";
                break;
            default:
                UNREACHABLE();
        }
        nameSink << type.getNominalSize();
    }
    TString nameString = TFunction::mangleName(nameSink.c_str());
    TName name(nameString);
    name.setInternal(true);
    return name;
}

TIntermSymbol *CreateBaseSymbol(const TType &type, TQualifier qualifier)
{
    TIntermSymbol *symbol = new TIntermSymbol(0, "base", type);
    symbol->setInternal(true);
    symbol->getTypePointer()->setQualifier(qualifier);
    return symbol;
}

TIntermSymbol *CreateIndexSymbol()
{
    TIntermSymbol *symbol = new TIntermSymbol(0, "index", TType(EbtInt, EbpHigh));
    symbol->setInternal(true);
    symbol->getTypePointer()->setQualifier(EvqIn);
    return symbol;
}

TIntermSymbol *CreateValueSymbol(const TType &type)
{
    TIntermSymbol *symbol = new TIntermSymbol(0, "value", type);
    symbol->setInternal(true);
    symbol->getTypePointer()->setQualifier(EvqIn);
    return symbol;
}

TIntermConstantUnion *CreateIntConstantNode(int i)
{
    TConstantUnion *constant = new TConstantUnion();
    constant->setIConst(i);
    return new TIntermConstantUnion(constant, TType(EbtInt, EbpHigh));
}

TIntermBinary *CreateIndexDirectBaseSymbolNode(const TType &indexedType,
                                               const TType &fieldType,
                                               const int index,
                                               TQualifier baseQualifier)
{
    TIntermBinary *indexNode = new TIntermBinary(EOpIndexDirect);
    indexNode->setType(fieldType);
    TIntermSymbol *baseSymbol = CreateBaseSymbol(indexedType, baseQualifier);
    indexNode->setLeft(baseSymbol);
    indexNode->setRight(CreateIntConstantNode(index));
    return indexNode;
}

TIntermBinary *CreateAssignValueSymbolNode(TIntermTyped *targetNode, const TType &assignedValueType)
{
    TIntermBinary *assignNode = new TIntermBinary(EOpAssign);
    assignNode->setType(assignedValueType);
    assignNode->setLeft(targetNode);
    assignNode->setRight(CreateValueSymbol(assignedValueType));
    return assignNode;
}

TIntermTyped *EnsureSignedInt(TIntermTyped *node)
{
    if (node->getBasicType() == EbtInt)
        return node;

    TIntermAggregate *convertedNode = new TIntermAggregate(EOpConstructInt);
    convertedNode->setType(TType(EbtInt));
    convertedNode->getSequence()->push_back(node);
    convertedNode->setPrecisionFromChildren();
    return convertedNode;
}

TType GetFieldType(const TType &indexedType)
{
    if (indexedType.isMatrix())
    {
        TType fieldType = TType(indexedType.getBasicType(), indexedType.getPrecision());
        fieldType.setPrimarySize(static_cast<unsigned char>(indexedType.getRows()));
        return fieldType;
    }
    else
    {
        return TType(indexedType.getBasicType(), indexedType.getPrecision());
    }
}

// Generate a read or write function for one field in a vector/matrix.
// Out-of-range indices are clamped. This is consistent with how ANGLE handles out-of-range
// indices in other places.
// Note that indices can be either int or uint. We create only int versions of the functions,
// and convert uint indices to int at the call site.
// read function example:
// float dyn_index_vec2(in vec2 base, in int index)
// {
//    switch(index)
//    {
//      case (0):
//        return base[0];
//      case (1):
//        return base[1];
//      default:
//        break;
//    }
//    if (index < 0)
//      return base[0];
//    return base[1];
// }
// write function example:
// void dyn_index_write_vec2(inout vec2 base, in int index, in float value)
// {
//    switch(index)
//    {
//      case (0):
//        base[0] = value;
//        return;
//      case (1):
//        base[1] = value;
//        return;
//      default:
//        break;
//    }
//    if (index < 0)
//    {
//      base[0] = value;
//      return;
//    }
//    base[1] = value;
// }
// Note that else is not used in above functions to avoid the RewriteElseBlocks transformation.
TIntermAggregate *GetIndexFunctionDefinition(TType type, bool write)
{
    ASSERT(!type.isArray());
    // Conservatively use highp here, even if the indexed type is not highp. That way the code can't
    // end up using mediump version of an indexing function for a highp value, if both mediump and
    // highp values are being indexed in the shader. For HLSL precision doesn't matter, but in
    // principle this code could be used with multiple backends.
    type.setPrecision(EbpHigh);
    TIntermAggregate *indexingFunction = new TIntermAggregate(EOpFunction);
    indexingFunction->setNameObj(GetIndexFunctionName(type, write));

    TType fieldType = GetFieldType(type);
    int numCases = 0;
    if (type.isMatrix())
    {
        numCases = type.getCols();
    }
    else
    {
        numCases = type.getNominalSize();
    }
    if (write)
    {
        indexingFunction->setType(TType(EbtVoid));
    }
    else
    {
        indexingFunction->setType(fieldType);
    }

    TIntermAggregate *paramsNode = new TIntermAggregate(EOpParameters);
    TQualifier baseQualifier = EvqInOut;
    if (!write)
        baseQualifier        = EvqIn;
    TIntermSymbol *baseParam = CreateBaseSymbol(type, baseQualifier);
    paramsNode->getSequence()->push_back(baseParam);
    TIntermSymbol *indexParam = CreateIndexSymbol();
    paramsNode->getSequence()->push_back(indexParam);
    if (write)
    {
        TIntermSymbol *valueParam = CreateValueSymbol(fieldType);
        paramsNode->getSequence()->push_back(valueParam);
    }
    indexingFunction->getSequence()->push_back(paramsNode);

    TIntermAggregate *statementList = new TIntermAggregate(EOpSequence);
    for (int i = 0; i < numCases; ++i)
    {
        TIntermCase *caseNode = new TIntermCase(CreateIntConstantNode(i));
        statementList->getSequence()->push_back(caseNode);

        TIntermBinary *indexNode =
            CreateIndexDirectBaseSymbolNode(type, fieldType, i, baseQualifier);
        if (write)
        {
            TIntermBinary *assignNode = CreateAssignValueSymbolNode(indexNode, fieldType);
            statementList->getSequence()->push_back(assignNode);
            TIntermBranch *returnNode = new TIntermBranch(EOpReturn, nullptr);
            statementList->getSequence()->push_back(returnNode);
        }
        else
        {
            TIntermBranch *returnNode = new TIntermBranch(EOpReturn, indexNode);
            statementList->getSequence()->push_back(returnNode);
        }
    }

    // Default case
    TIntermCase *defaultNode = new TIntermCase(nullptr);
    statementList->getSequence()->push_back(defaultNode);
    TIntermBranch *breakNode = new TIntermBranch(EOpBreak, nullptr);
    statementList->getSequence()->push_back(breakNode);

    TIntermSwitch *switchNode = new TIntermSwitch(CreateIndexSymbol(), statementList);

    TIntermAggregate *bodyNode = new TIntermAggregate(EOpSequence);
    bodyNode->getSequence()->push_back(switchNode);

    TIntermBinary *cond = new TIntermBinary(EOpLessThan);
    cond->setType(TType(EbtBool, EbpUndefined));
    cond->setLeft(CreateIndexSymbol());
    cond->setRight(CreateIntConstantNode(0));

    // Two blocks: one accesses (either reads or writes) the first element and returns,
    // the other accesses the last element.
    TIntermAggregate *useFirstBlock = new TIntermAggregate(EOpSequence);
    TIntermAggregate *useLastBlock = new TIntermAggregate(EOpSequence);
    TIntermBinary *indexFirstNode =
        CreateIndexDirectBaseSymbolNode(type, fieldType, 0, baseQualifier);
    TIntermBinary *indexLastNode =
        CreateIndexDirectBaseSymbolNode(type, fieldType, numCases - 1, baseQualifier);
    if (write)
    {
        TIntermBinary *assignFirstNode = CreateAssignValueSymbolNode(indexFirstNode, fieldType);
        useFirstBlock->getSequence()->push_back(assignFirstNode);
        TIntermBranch *returnNode = new TIntermBranch(EOpReturn, nullptr);
        useFirstBlock->getSequence()->push_back(returnNode);

        TIntermBinary *assignLastNode = CreateAssignValueSymbolNode(indexLastNode, fieldType);
        useLastBlock->getSequence()->push_back(assignLastNode);
    }
    else
    {
        TIntermBranch *returnFirstNode = new TIntermBranch(EOpReturn, indexFirstNode);
        useFirstBlock->getSequence()->push_back(returnFirstNode);

        TIntermBranch *returnLastNode = new TIntermBranch(EOpReturn, indexLastNode);
        useLastBlock->getSequence()->push_back(returnLastNode);
    }
    TIntermSelection *ifNode = new TIntermSelection(cond, useFirstBlock, nullptr);
    bodyNode->getSequence()->push_back(ifNode);
    bodyNode->getSequence()->push_back(useLastBlock);

    indexingFunction->getSequence()->push_back(bodyNode);

    return indexingFunction;
}

class RemoveDynamicIndexingTraverser : public TLValueTrackingTraverser
{
  public:
    RemoveDynamicIndexingTraverser(const TSymbolTable &symbolTable, int shaderVersion);

    bool visitBinary(Visit visit, TIntermBinary *node) override;

    void insertHelperDefinitions(TIntermNode *root);

    void nextIteration();

    bool usedTreeInsertion() const { return mUsedTreeInsertion; }

  protected:
    // Sets of types that are indexed. Note that these can not store multiple variants
    // of the same type with different precisions - only one precision gets stored.
    std::set<TType> mIndexedVecAndMatrixTypes;
    std::set<TType> mWrittenVecAndMatrixTypes;

    bool mUsedTreeInsertion;

    // When true, the traverser will remove side effects from any indexing expression.
    // This is done so that in code like
    //   V[j++][i]++.
    // where V is an array of vectors, j++ will only be evaluated once.
    bool mRemoveIndexSideEffectsInSubtree;
};

RemoveDynamicIndexingTraverser::RemoveDynamicIndexingTraverser(const TSymbolTable &symbolTable,
                                                               int shaderVersion)
    : TLValueTrackingTraverser(true, false, false, symbolTable, shaderVersion),
      mUsedTreeInsertion(false),
      mRemoveIndexSideEffectsInSubtree(false)
{
}

void RemoveDynamicIndexingTraverser::insertHelperDefinitions(TIntermNode *root)
{
    TIntermAggregate *rootAgg = root->getAsAggregate();
    ASSERT(rootAgg != nullptr && rootAgg->getOp() == EOpSequence);
    TIntermSequence insertions;
    for (TType type : mIndexedVecAndMatrixTypes)
    {
        insertions.push_back(GetIndexFunctionDefinition(type, false));
    }
    for (TType type : mWrittenVecAndMatrixTypes)
    {
        insertions.push_back(GetIndexFunctionDefinition(type, true));
    }
    mInsertions.push_back(NodeInsertMultipleEntry(rootAgg, 0, insertions, TIntermSequence()));
}

// Create a call to dyn_index_*() based on an indirect indexing op node
TIntermAggregate *CreateIndexFunctionCall(TIntermBinary *node,
                                          TIntermTyped *indexedNode,
                                          TIntermTyped *index)
{
    ASSERT(node->getOp() == EOpIndexIndirect);
    TIntermAggregate *indexingCall = new TIntermAggregate(EOpFunctionCall);
    indexingCall->setLine(node->getLine());
    indexingCall->setUserDefined();
    indexingCall->setNameObj(GetIndexFunctionName(indexedNode->getType(), false));
    indexingCall->getSequence()->push_back(indexedNode);
    indexingCall->getSequence()->push_back(index);

    TType fieldType = GetFieldType(indexedNode->getType());
    indexingCall->setType(fieldType);
    return indexingCall;
}

TIntermAggregate *CreateIndexedWriteFunctionCall(TIntermBinary *node,
                                                 TIntermTyped *index,
                                                 TIntermTyped *writtenValue)
{
    // Deep copy the left node so that two pointers to the same node don't end up in the tree.
    TIntermNode *leftCopy = node->getLeft()->deepCopy();
    ASSERT(leftCopy != nullptr && leftCopy->getAsTyped() != nullptr);
    TIntermAggregate *indexedWriteCall =
        CreateIndexFunctionCall(node, leftCopy->getAsTyped(), index);
    indexedWriteCall->setNameObj(GetIndexFunctionName(node->getLeft()->getType(), true));
    indexedWriteCall->setType(TType(EbtVoid));
    indexedWriteCall->getSequence()->push_back(writtenValue);
    return indexedWriteCall;
}

bool RemoveDynamicIndexingTraverser::visitBinary(Visit visit, TIntermBinary *node)
{
    if (mUsedTreeInsertion)
        return false;

    if (node->getOp() == EOpIndexIndirect)
    {
        if (mRemoveIndexSideEffectsInSubtree)
        {
            ASSERT(node->getRight()->hasSideEffects());
            // In case we're just removing index side effects, convert
            //   v_expr[index_expr]
            // to this:
            //   int s0 = index_expr; v_expr[s0];
            // Now v_expr[s0] can be safely executed several times without unintended side effects.

            // Init the temp variable holding the index
            TIntermAggregate *initIndex = createTempInitDeclaration(node->getRight());
            insertStatementInParentBlock(initIndex);
            mUsedTreeInsertion = true;

            // Replace the index with the temp variable
            TIntermSymbol *tempIndex = createTempSymbol(node->getRight()->getType());
            queueReplacementWithParent(node, node->getRight(), tempIndex, OriginalNode::IS_DROPPED);
        }
        else if (IntermNodePatternMatcher::IsDynamicIndexingOfVectorOrMatrix(node))
        {
            bool write = isLValueRequiredHere();

#if defined(ANGLE_ENABLE_ASSERTS)
            // Make sure that IntermNodePatternMatcher is consistent with the slightly differently
            // implemented checks in this traverser.
            IntermNodePatternMatcher matcher(
                IntermNodePatternMatcher::kDynamicIndexingOfVectorOrMatrixInLValue);
            ASSERT(matcher.match(node, getParentNode(), isLValueRequiredHere()) == write);
#endif

            TType type = node->getLeft()->getType();
            mIndexedVecAndMatrixTypes.insert(type);

            if (write)
            {
                // Convert:
                //   v_expr[index_expr]++;
                // to this:
                //   int s0 = index_expr; float s1 = dyn_index(v_expr, s0); s1++;
                //   dyn_index_write(v_expr, s0, s1);
                // This works even if index_expr has some side effects.
                if (node->getLeft()->hasSideEffects())
                {
                    // If v_expr has side effects, those need to be removed before proceeding.
                    // Otherwise the side effects of v_expr would be evaluated twice.
                    // The only case where an l-value can have side effects is when it is
                    // indexing. For example, it can be V[j++] where V is an array of vectors.
                    mRemoveIndexSideEffectsInSubtree = true;
                    return true;
                }
                // TODO(oetuaho@nvidia.com): This is not optimal if the expression using the value
                // only writes it and doesn't need the previous value. http://anglebug.com/1116

                mWrittenVecAndMatrixTypes.insert(type);
                TType fieldType = GetFieldType(type);

                TIntermSequence insertionsBefore;
                TIntermSequence insertionsAfter;

                // Store the index in a temporary signed int variable.
                TIntermTyped *indexInitializer = EnsureSignedInt(node->getRight());
                TIntermAggregate *initIndex = createTempInitDeclaration(indexInitializer);
                initIndex->setLine(node->getLine());
                insertionsBefore.push_back(initIndex);

                TIntermAggregate *indexingCall = CreateIndexFunctionCall(
                    node, node->getLeft(), createTempSymbol(indexInitializer->getType()));

                // Create a node for referring to the index after the nextTemporaryIndex() call
                // below.
                TIntermSymbol *tempIndex = createTempSymbol(indexInitializer->getType());

                nextTemporaryIndex();  // From now on, creating temporary symbols that refer to the
                                       // field value.
                insertionsBefore.push_back(createTempInitDeclaration(indexingCall));

                TIntermAggregate *indexedWriteCall =
                    CreateIndexedWriteFunctionCall(node, tempIndex, createTempSymbol(fieldType));
                insertionsAfter.push_back(indexedWriteCall);
                insertStatementsInParentBlock(insertionsBefore, insertionsAfter);
                queueReplacement(node, createTempSymbol(fieldType), OriginalNode::IS_DROPPED);
                mUsedTreeInsertion = true;
            }
            else
            {
                // The indexed value is not being written, so we can simply convert
                //   v_expr[index_expr]
                // into
                //   dyn_index(v_expr, index_expr)
                // If the index_expr is unsigned, we'll convert it to signed.
                ASSERT(!mRemoveIndexSideEffectsInSubtree);
                TIntermAggregate *indexingCall = CreateIndexFunctionCall(
                    node, node->getLeft(), EnsureSignedInt(node->getRight()));
                queueReplacement(node, indexingCall, OriginalNode::IS_DROPPED);
            }
        }
    }
    return !mUsedTreeInsertion;
}

void RemoveDynamicIndexingTraverser::nextIteration()
{
    mUsedTreeInsertion               = false;
    mRemoveIndexSideEffectsInSubtree = false;
    nextTemporaryIndex();
}

}  // namespace

void RemoveDynamicIndexing(TIntermNode *root,
                           unsigned int *temporaryIndex,
                           const TSymbolTable &symbolTable,
                           int shaderVersion)
{
    RemoveDynamicIndexingTraverser traverser(symbolTable, shaderVersion);
    ASSERT(temporaryIndex != nullptr);
    traverser.useTemporaryIndex(temporaryIndex);
    do
    {
        traverser.nextIteration();
        root->traverse(&traverser);
        traverser.updateTree();
    } while (traverser.usedTreeInsertion());
    traverser.insertHelperDefinitions(root);
    traverser.updateTree();
}