1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SKSL_METALCODEGENERATOR
9 #define SKSL_METALCODEGENERATOR
10 
11 #include <stack>
12 #include <tuple>
13 #include <unordered_map>
14 
15 #include "SkSLCodeGenerator.h"
16 #include "SkSLStringStream.h"
17 #include "ir/SkSLBinaryExpression.h"
18 #include "ir/SkSLBoolLiteral.h"
19 #include "ir/SkSLConstructor.h"
20 #include "ir/SkSLDoStatement.h"
21 #include "ir/SkSLExtension.h"
22 #include "ir/SkSLFloatLiteral.h"
23 #include "ir/SkSLIfStatement.h"
24 #include "ir/SkSLIndexExpression.h"
25 #include "ir/SkSLInterfaceBlock.h"
26 #include "ir/SkSLIntLiteral.h"
27 #include "ir/SkSLFieldAccess.h"
28 #include "ir/SkSLForStatement.h"
29 #include "ir/SkSLFunctionCall.h"
30 #include "ir/SkSLFunctionDeclaration.h"
31 #include "ir/SkSLFunctionDefinition.h"
32 #include "ir/SkSLPrefixExpression.h"
33 #include "ir/SkSLPostfixExpression.h"
34 #include "ir/SkSLProgramElement.h"
35 #include "ir/SkSLReturnStatement.h"
36 #include "ir/SkSLSetting.h"
37 #include "ir/SkSLStatement.h"
38 #include "ir/SkSLSwitchStatement.h"
39 #include "ir/SkSLSwizzle.h"
40 #include "ir/SkSLTernaryExpression.h"
41 #include "ir/SkSLVarDeclarations.h"
42 #include "ir/SkSLVarDeclarationsStatement.h"
43 #include "ir/SkSLVariableReference.h"
44 #include "ir/SkSLWhileStatement.h"
45 
46 namespace SkSL {
47 
48 #define kLast_Capability SpvCapabilityMultiViewport
49 
50 /**
51  * Converts a Program into Metal code.
52  */
53 class MetalCodeGenerator : public CodeGenerator {
54 public:
55     enum Precedence {
56         kParentheses_Precedence    =  1,
57         kPostfix_Precedence        =  2,
58         kPrefix_Precedence         =  3,
59         kMultiplicative_Precedence =  4,
60         kAdditive_Precedence       =  5,
61         kShift_Precedence          =  6,
62         kRelational_Precedence     =  7,
63         kEquality_Precedence       =  8,
64         kBitwiseAnd_Precedence     =  9,
65         kBitwiseXor_Precedence     = 10,
66         kBitwiseOr_Precedence      = 11,
67         kLogicalAnd_Precedence     = 12,
68         kLogicalXor_Precedence     = 13,
69         kLogicalOr_Precedence      = 14,
70         kTernary_Precedence        = 15,
71         kAssignment_Precedence     = 16,
72         kSequence_Precedence       = 17,
73         kTopLevel_Precedence       = kSequence_Precedence
74     };
75 
76     MetalCodeGenerator(const Context* context, const Program* program, ErrorReporter* errors,
77                       OutputStream* out)
78     : INHERITED(program, errors, out)
79     , fLineEnding("\n")
80     , fContext(*context) {}
81 
82     bool generateCode() override;
83 
84 protected:
85     typedef int Requirements;
86     static constexpr Requirements kNo_Requirements      = 0;
87     static constexpr Requirements kInputs_Requirement   = 1 << 0;
88     static constexpr Requirements kOutputs_Requirement  = 1 << 1;
89     static constexpr Requirements kUniforms_Requirement = 1 << 2;
90 
91     void write(const char* s);
92 
93     void writeLine();
94 
95     void writeLine(const char* s);
96 
97     void write(const String& s);
98 
99     void writeLine(const String& s);
100 
101     void writeHeader();
102 
103     void writeUniformStruct();
104 
105     void writeInputStruct();
106 
107     void writeOutputStruct();
108 
109     void writePrecisionModifier();
110 
111     void writeType(const Type& type);
112 
113     void writeExtension(const Extension& ext);
114 
115     void writeInterfaceBlock(const InterfaceBlock& intf);
116 
117     void writeFunctionStart(const FunctionDeclaration& f);
118 
119     void writeFunctionDeclaration(const FunctionDeclaration& f);
120 
121     void writeFunction(const FunctionDefinition& f);
122 
123     void writeLayout(const Layout& layout);
124 
125     void writeModifiers(const Modifiers& modifiers, bool globalContext);
126 
127     void writeGlobalVars(const VarDeclaration& vs);
128 
129     void writeVarInitializer(const Variable& var, const Expression& value);
130 
131     void writeVarDeclarations(const VarDeclarations& decl, bool global);
132 
133     void writeFragCoord();
134 
135     void writeVariableReference(const VariableReference& ref);
136 
137     void writeExpression(const Expression& expr, Precedence parentPrecedence);
138 
139     void writeIntrinsicCall(const FunctionCall& c);
140 
141     void writeMinAbsHack(Expression& absExpr, Expression& otherExpr);
142 
143     void writeFunctionCall(const FunctionCall& c);
144 
145     void writeConstructor(const Constructor& c);
146 
147     void writeFieldAccess(const FieldAccess& f);
148 
149     void writeSwizzle(const Swizzle& swizzle);
150 
151     static Precedence GetBinaryPrecedence(Token::Kind op);
152 
153     void writeBinaryExpression(const BinaryExpression& b, Precedence parentPrecedence);
154 
155     void writeTernaryExpression(const TernaryExpression& t, Precedence parentPrecedence);
156 
157     void writeIndexExpression(const IndexExpression& expr);
158 
159     void writePrefixExpression(const PrefixExpression& p, Precedence parentPrecedence);
160 
161     void writePostfixExpression(const PostfixExpression& p, Precedence parentPrecedence);
162 
163     void writeBoolLiteral(const BoolLiteral& b);
164 
165     void writeIntLiteral(const IntLiteral& i);
166 
167     void writeFloatLiteral(const FloatLiteral& f);
168 
169     void writeSetting(const Setting& s);
170 
171     void writeStatement(const Statement& s);
172 
173     void writeStatements(const std::vector<std::unique_ptr<Statement>>& statements);
174 
175     void writeBlock(const Block& b);
176 
177     void writeIfStatement(const IfStatement& stmt);
178 
179     void writeForStatement(const ForStatement& f);
180 
181     void writeWhileStatement(const WhileStatement& w);
182 
183     void writeDoStatement(const DoStatement& d);
184 
185     void writeSwitchStatement(const SwitchStatement& s);
186 
187     void writeReturnStatement(const ReturnStatement& r);
188 
189     void writeProgramElement(const ProgramElement& e);
190 
191     Requirements requirements(const FunctionDeclaration& f);
192 
193     Requirements requirements(const Expression& e);
194 
195     Requirements requirements(const Statement& e);
196 
197     const char* fLineEnding;
198     const Context& fContext;
199     StringStream fHeader;
200     String fFunctionHeader;
201     Program::Kind fProgramKind;
202     int fVarCount = 0;
203     int fIndentation = 0;
204     bool fAtLineStart = false;
205     // Keeps track of which struct types we have written. Given that we are unlikely to ever write
206     // more than one or two structs per shader, a simple linear search will be faster than anything
207     // fancier.
208     std::vector<const Type*> fWrittenStructs;
209     // true if we have run into usages of dFdx / dFdy
210     bool fFoundDerivatives = false;
211     bool fFoundImageDecl = false;
212     std::unordered_map<const FunctionDeclaration*, Requirements> fRequirements;
213     bool fSetupFragPositionGlobal = false;
214     bool fSetupFragPositionLocal = false;
215     int fUniformBuffer = -1;
216 
217     typedef CodeGenerator INHERITED;
218 };
219 
220 }
221 
222 #endif
223