1 //
2 // Copyright (c) 2002-2012 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/VersionGLSL.h"
8
9 static const int GLSL_VERSION_110 = 110;
10 static const int GLSL_VERSION_120 = 120;
11
12 // We need to scan for the following:
13 // 1. "invariant" keyword: This can occur in both - vertex and fragment shaders
14 // but only at the global scope.
15 // 2. "gl_PointCoord" built-in variable: This can only occur in fragment shader
16 // but inside any scope.
17 // 3. Call to a matrix constructor with another matrix as argument.
18 // (These constructors were reserved in GLSL version 1.10.)
19 // 4. Arrays as "out" function parameters.
20 // GLSL spec section 6.1.1: "When calling a function, expressions that do
21 // not evaluate to l-values cannot be passed to parameters declared as
22 // out or inout."
23 // GLSL 1.1 section 5.8: "Other binary or unary expressions,
24 // non-dereferenced arrays, function names, swizzles with repeated fields,
25 // and constants cannot be l-values."
26 // GLSL 1.2 relaxed the restriction on arrays, section 5.8: "Variables that
27 // are built-in types, entire structures or arrays... are all l-values."
28 //
29 // TODO(alokp): The following two cases of invariant decalaration get lost
30 // during parsing - they do not get carried over to the intermediate tree.
31 // Handle these cases:
32 // 1. When a pragma is used to force all output variables to be invariant:
33 // - #pragma STDGL invariant(all)
34 // 2. When a previously decalared or built-in variable is marked invariant:
35 // - invariant gl_Position;
36 // - varying vec3 color; invariant color;
37 //
TVersionGLSL(ShShaderType type)38 TVersionGLSL::TVersionGLSL(ShShaderType type)
39 : mShaderType(type),
40 mVersion(GLSL_VERSION_110)
41 {
42 }
43
visitSymbol(TIntermSymbol * node)44 void TVersionGLSL::visitSymbol(TIntermSymbol* node)
45 {
46 if (node->getSymbol() == "gl_PointCoord")
47 updateVersion(GLSL_VERSION_120);
48 }
49
visitConstantUnion(TIntermConstantUnion *)50 void TVersionGLSL::visitConstantUnion(TIntermConstantUnion*)
51 {
52 }
53
visitBinary(Visit,TIntermBinary *)54 bool TVersionGLSL::visitBinary(Visit, TIntermBinary*)
55 {
56 return true;
57 }
58
visitUnary(Visit,TIntermUnary *)59 bool TVersionGLSL::visitUnary(Visit, TIntermUnary*)
60 {
61 return true;
62 }
63
visitSelection(Visit,TIntermSelection *)64 bool TVersionGLSL::visitSelection(Visit, TIntermSelection*)
65 {
66 return true;
67 }
68
visitAggregate(Visit,TIntermAggregate * node)69 bool TVersionGLSL::visitAggregate(Visit, TIntermAggregate* node)
70 {
71 bool visitChildren = true;
72
73 switch (node->getOp()) {
74 case EOpSequence:
75 // We need to visit sequence children to get to global or inner scope.
76 visitChildren = true;
77 break;
78 case EOpDeclaration: {
79 const TIntermSequence& sequence = node->getSequence();
80 TQualifier qualifier = sequence.front()->getAsTyped()->getQualifier();
81 if ((qualifier == EvqInvariantVaryingIn) ||
82 (qualifier == EvqInvariantVaryingOut)) {
83 updateVersion(GLSL_VERSION_120);
84 }
85 break;
86 }
87 case EOpParameters: {
88 const TIntermSequence& params = node->getSequence();
89 for (TIntermSequence::const_iterator iter = params.begin();
90 iter != params.end(); ++iter)
91 {
92 const TIntermTyped* param = (*iter)->getAsTyped();
93 if (param->isArray())
94 {
95 TQualifier qualifier = param->getQualifier();
96 if ((qualifier == EvqOut) || (qualifier == EvqInOut))
97 {
98 updateVersion(GLSL_VERSION_120);
99 break;
100 }
101 }
102 }
103 // Fully processed. No need to visit children.
104 visitChildren = false;
105 break;
106 }
107 case EOpConstructMat2:
108 case EOpConstructMat3:
109 case EOpConstructMat4: {
110 const TIntermSequence& sequence = node->getSequence();
111 if (sequence.size() == 1) {
112 TIntermTyped* typed = sequence.front()->getAsTyped();
113 if (typed && typed->isMatrix()) {
114 updateVersion(GLSL_VERSION_120);
115 }
116 }
117 break;
118 }
119
120 default: break;
121 }
122
123 return visitChildren;
124 }
125
visitLoop(Visit,TIntermLoop *)126 bool TVersionGLSL::visitLoop(Visit, TIntermLoop*)
127 {
128 return true;
129 }
130
visitBranch(Visit,TIntermBranch *)131 bool TVersionGLSL::visitBranch(Visit, TIntermBranch*)
132 {
133 return true;
134 }
135
updateVersion(int version)136 void TVersionGLSL::updateVersion(int version)
137 {
138 mVersion = std::max(version, mVersion);
139 }
140
141