1 //
2 // Copyright 2002 The ANGLE Project Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style license that can be
4 // found in the LICENSE file.
5 //
6
7 #include "compiler/translator/tree_ops/gl/RegenerateStructNames.h"
8
9 #include "common/debug.h"
10 #include "compiler/translator/Compiler.h"
11 #include "compiler/translator/ImmutableStringBuilder.h"
12 #include "compiler/translator/SymbolTable.h"
13 #include "compiler/translator/tree_util/IntermTraverse.h"
14
15 #include <set>
16
17 namespace sh
18 {
19
20 namespace
21 {
22 constexpr const ImmutableString kPrefix("_webgl_struct_");
23 } // anonymous namespace
24
25 class RegenerateStructNamesTraverser : public TIntermTraverser
26 {
27 public:
RegenerateStructNamesTraverser(TSymbolTable * symbolTable)28 RegenerateStructNamesTraverser(TSymbolTable *symbolTable)
29 : TIntermTraverser(true, false, false, symbolTable), mScopeDepth(0)
30 {}
31
32 protected:
33 void visitSymbol(TIntermSymbol *) override;
34 bool visitBlock(Visit, TIntermBlock *block) override;
35
36 private:
37 // Indicating the depth of the current scope.
38 // The global scope is 1.
39 int mScopeDepth;
40
41 // If a struct is declared globally, push its ID in this set.
42 std::set<int> mDeclaredGlobalStructs;
43 };
44
visitSymbol(TIntermSymbol * symbol)45 void RegenerateStructNamesTraverser::visitSymbol(TIntermSymbol *symbol)
46 {
47 ASSERT(symbol);
48 const TType &type = symbol->getType();
49 const TStructure *userType = type.getStruct();
50 if (!userType)
51 return;
52
53 if (userType->symbolType() == SymbolType::BuiltIn ||
54 userType->symbolType() == SymbolType::Empty)
55 {
56 // Built-in struct or nameless struct, do not touch it.
57 return;
58 }
59
60 int uniqueId = userType->uniqueId().get();
61
62 ASSERT(mScopeDepth > 0);
63 if (mScopeDepth == 1)
64 {
65 // If a struct is defined at global scope, we don't map its name.
66 // This is because at global level, the struct might be used to
67 // declare a uniform, so the same name needs to stay the same for
68 // vertex/fragment shaders. However, our mapping uses internal ID,
69 // which will be different for the same struct in vertex/fragment
70 // shaders.
71 // This is OK because names for any structs defined in other scopes
72 // will begin with "_webgl", which is reserved. So there will be
73 // no conflicts among unmapped struct names from global scope and
74 // mapped struct names from other scopes.
75 // However, we need to keep track of these global structs, so if a
76 // variable is used in a local scope, we don't try to modify the
77 // struct name through that variable.
78 mDeclaredGlobalStructs.insert(uniqueId);
79 return;
80 }
81 if (mDeclaredGlobalStructs.count(uniqueId) > 0)
82 return;
83 // Map {name} to _webgl_struct_{uniqueId}_{name}.
84 if (userType->name().beginsWith(kPrefix))
85 {
86 // The name has already been regenerated.
87 return;
88 }
89 ImmutableStringBuilder tmp(kPrefix.length() + sizeof(uniqueId) * 2u + 1u +
90 userType->name().length());
91 tmp << kPrefix;
92 tmp.appendHex(uniqueId);
93 tmp << '_' << userType->name();
94
95 // TODO(oetuaho): Add another mechanism to change symbol names so that the const_cast is not
96 // needed.
97 const_cast<TStructure *>(userType)->setName(tmp);
98 }
99
visitBlock(Visit,TIntermBlock * block)100 bool RegenerateStructNamesTraverser::visitBlock(Visit, TIntermBlock *block)
101 {
102 ++mScopeDepth;
103 TIntermSequence &sequence = *(block->getSequence());
104 for (TIntermNode *node : sequence)
105 {
106 node->traverse(this);
107 }
108 --mScopeDepth;
109 return false;
110 }
111
RegenerateStructNames(TCompiler * compiler,TIntermBlock * root,TSymbolTable * symbolTable)112 bool RegenerateStructNames(TCompiler *compiler, TIntermBlock *root, TSymbolTable *symbolTable)
113 {
114 RegenerateStructNamesTraverser traverser(symbolTable);
115 root->traverse(&traverser);
116 return compiler->validateAST(root);
117 }
118
119 } // namespace sh
120