| /* |
| * Copyright 2020 Google LLC |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #ifndef SkSLAnalysis_DEFINED |
| #define SkSLAnalysis_DEFINED |
| |
| #include "include/private/SkSLSampleUsage.h" |
| #include "include/private/base/SkTArray.h" |
| |
| #include <cstdint> |
| #include <memory> |
| #include <set> |
| #include <vector> |
| |
| namespace SkSL { |
| |
| class Context; |
| class ErrorReporter; |
| class Expression; |
| class FunctionDeclaration; |
| class FunctionDefinition; |
| class Position; |
| class ProgramElement; |
| class ProgramUsage; |
| class Statement; |
| class SymbolTable; |
| class Variable; |
| class VariableReference; |
| enum class VariableRefKind : int8_t; |
| struct ForLoopPositions; |
| struct LoopUnrollInfo; |
| struct Module; |
| struct Program; |
| |
| /** |
| * Provides utilities for analyzing SkSL statically before it's composed into a full program. |
| */ |
| namespace Analysis { |
| |
| /** |
| * Determines how `program` samples `child`. By default, assumes that the sample coords |
| * (SK_MAIN_COORDS_BUILTIN) might be modified, so `child.eval(sampleCoords)` is treated as |
| * Explicit. If writesToSampleCoords is false, treats that as PassThrough, instead. |
| * If elidedSampleCoordCount is provided, the pointed to value will be incremented by the |
| * number of sample calls where the above rewrite was performed. |
| */ |
| SampleUsage GetSampleUsage(const Program& program, |
| const Variable& child, |
| bool writesToSampleCoords = true, |
| int* elidedSampleCoordCount = nullptr); |
| |
| bool ReferencesBuiltin(const Program& program, int builtin); |
| |
| bool ReferencesSampleCoords(const Program& program); |
| bool ReferencesFragCoords(const Program& program); |
| |
| bool CallsSampleOutsideMain(const Program& program); |
| |
| bool CallsColorTransformIntrinsics(const Program& program); |
| |
| /** |
| * Determines if `function` always returns an opaque color (a vec4 where the last component is known |
| * to be 1). This is conservative, and based on constant expression analysis. |
| */ |
| bool ReturnsOpaqueColor(const FunctionDefinition& function); |
| |
| /** |
| * Checks for recursion or overly-deep function-call chains, and rejects programs which have them. |
| * Also, computes the size of the program in a completely flattened state--loops fully unrolled, |
| * function calls inlined--and rejects programs that exceed an arbitrary upper bound. This is |
| * intended to prevent absurdly large programs from overwhemling SkVM. Only strict-ES2 mode is |
| * supported; complex control flow is not SkVM-compatible (and this becomes the halting problem) |
| */ |
| bool CheckProgramStructure(const Program& program, bool enforceSizeLimit); |
| |
| /** Determines if `expr` contains a reference to the variable sk_RTAdjust. */ |
| bool ContainsRTAdjust(const Expression& expr); |
| |
| /** Determines if `expr` has any side effects. (Is the expression state-altering or pure?) */ |
| bool HasSideEffects(const Expression& expr); |
| |
| /** Determines if `expr` is a compile-time constant (composed of just constructors and literals). */ |
| bool IsCompileTimeConstant(const Expression& expr); |
| |
| /** |
| * Detect an orphaned variable declaration outside of a scope, e.g. if (true) int a;. Returns |
| * true if an error was reported. |
| */ |
| bool DetectVarDeclarationWithoutScope(const Statement& stmt, ErrorReporter* errors = nullptr); |
| |
| int NodeCountUpToLimit(const FunctionDefinition& function, int limit); |
| |
| /** |
| * Finds unconditional exits from a switch-case. Returns true if this statement unconditionally |
| * causes an exit from this switch (via continue, break or return). |
| */ |
| bool SwitchCaseContainsUnconditionalExit(Statement& stmt); |
| |
| /** |
| * Finds conditional exits from a switch-case. Returns true if this statement contains a |
| * conditional that wraps a potential exit from the switch (via continue, break or return). |
| */ |
| bool SwitchCaseContainsConditionalExit(Statement& stmt); |
| |
| std::unique_ptr<ProgramUsage> GetUsage(const Program& program); |
| std::unique_ptr<ProgramUsage> GetUsage(const Module& module); |
| |
| bool StatementWritesToVariable(const Statement& stmt, const Variable& var); |
| |
| /** |
| * Returns true if the expression can be assigned-into. Pass `info` if you want to know the |
| * VariableReference that will be written to. Pass `errors` to report an error for expressions that |
| * are not actually writable. |
| */ |
| struct AssignmentInfo { |
| VariableReference* fAssignedVar = nullptr; |
| }; |
| bool IsAssignable(Expression& expr, AssignmentInfo* info = nullptr, |
| ErrorReporter* errors = nullptr); |
| |
| /** |
| * Updates the `refKind` field of the VariableReference at the top level of `expr`. |
| * If `expr` can be assigned to (`IsAssignable`), true is returned and no errors are reported. |
| * If not, false is returned. and an error is reported if `errors` is non-null. |
| */ |
| bool UpdateVariableRefKind(Expression* expr, VariableRefKind kind, ErrorReporter* errors = nullptr); |
| |
| /** |
| * A "trivial" expression is one where we'd feel comfortable cloning it multiple times in |
| * the code, without worrying about incurring a performance penalty. Examples: |
| * - true |
| * - 3.14159265 |
| * - myIntVariable |
| * - myColor.rgb |
| * - myArray[123] |
| * - myStruct.myField |
| * - half4(0) |
| * |
| * Trivial-ness is stackable. Somewhat large expressions can occasionally make the cut: |
| * - half4(myColor.a) |
| * - myStruct.myArrayField[7].xzy |
| */ |
| bool IsTrivialExpression(const Expression& expr); |
| |
| /** |
| * Returns true if both expression trees are the same. Used by the optimizer to look for self- |
| * assignment or self-comparison; won't necessarily catch complex cases. Rejects expressions |
| * that may cause side effects. |
| */ |
| bool IsSameExpressionTree(const Expression& left, const Expression& right); |
| |
| /** |
| * Returns true if expr is a constant-expression, as defined by GLSL 1.0, section 5.10. |
| * A constant expression is one of: |
| * - A literal value |
| * - A global or local variable qualified as 'const', excluding function parameters |
| * - An expression formed by an operator on operands that are constant expressions, including |
| * getting an element of a constant vector or a constant matrix, or a field of a constant |
| * structure |
| * - A constructor whose arguments are all constant expressions |
| * - A built-in function call whose arguments are all constant expressions, with the exception |
| * of the texture lookup functions |
| */ |
| bool IsConstantExpression(const Expression& expr); |
| |
| /** |
| * Returns true if expr is a valid constant-index-expression, as defined by GLSL 1.0, Appendix A, |
| * Section 5. A constant-index-expression is: |
| * - A constant-expression |
| * - Loop indices (as defined in Appendix A, Section 4) |
| * - Expressions composed of both of the above |
| */ |
| bool IsConstantIndexExpression(const Expression& expr, |
| const std::set<const Variable*>* loopIndices); |
| |
| /** |
| * Ensures that a for-loop meets the strict requirements of The OpenGL ES Shading Language 1.00, |
| * Appendix A, Section 4. |
| * If the requirements are met, information about the loop's structure is returned. |
| * If the requirements are not met, the problem is reported via `errors` (if not nullptr), and |
| * null is returned. |
| */ |
| std::unique_ptr<LoopUnrollInfo> GetLoopUnrollInfo(Position pos, |
| const ForLoopPositions& positions, |
| const Statement* loopInitializer, |
| const Expression* loopTest, |
| const Expression* loopNext, |
| const Statement* loopStatement, |
| ErrorReporter* errors); |
| |
| void ValidateIndexingForES2(const ProgramElement& pe, ErrorReporter& errors); |
| |
| /** Detects functions that fail to return a value on at least one path. */ |
| bool CanExitWithoutReturningValue(const FunctionDeclaration& funcDecl, const Statement& body); |
| |
| /** Determines if a given function has multiple and/or early returns. */ |
| enum class ReturnComplexity { |
| kSingleSafeReturn, |
| kScopedReturns, |
| kEarlyReturns, |
| }; |
| ReturnComplexity GetReturnComplexity(const FunctionDefinition& funcDef); |
| |
| /** |
| * Runs at finalization time to perform any last-minute correctness checks: |
| * - Reports dangling FunctionReference or TypeReference expressions |
| * - Reports function `out` params which are never written to (structs are currently exempt) |
| */ |
| void DoFinalizationChecks(const Program& program); |
| |
| /** |
| * Error checks compute shader in/outs and returns a vector containing them ordered by location. |
| */ |
| SkTArray<const SkSL::Variable*> GetComputeShaderMainParams(const Context& context, |
| const Program& program); |
| |
| /** |
| * Tracks the symbol table stack, in conjunction with a ProgramVisitor. Inside `visitStatement`, |
| * pass the current statement and a symbol-table vector to a SymbolTableStackBuilder and the symbol |
| * table stack will be maintained automatically. |
| */ |
| class SymbolTableStackBuilder { |
| public: |
| // If the passed-in statement holds a symbol table, adds it to the stack. |
| SymbolTableStackBuilder(const Statement* stmt, |
| std::vector<std::shared_ptr<SymbolTable>>* stack); |
| |
| // If a symbol table was added to the stack earlier, removes it from the stack. |
| ~SymbolTableStackBuilder(); |
| |
| private: |
| std::vector<std::shared_ptr<SymbolTable>>* fStackToPop = nullptr; |
| }; |
| |
| } // namespace Analysis |
| } // namespace SkSL |
| |
| #endif |