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/*
* 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 SKSL_INLINER
#define SKSL_INLINER
#include <memory>
#include <unordered_map>
#include "src/sksl/SkSLMangler.h"
#include "src/sksl/ir/SkSLProgram.h"
#include "src/sksl/ir/SkSLVariableReference.h"
namespace SkSL {
class Block;
class Context;
class Expression;
class FunctionCall;
class FunctionDefinition;
struct InlineCandidate;
struct InlineCandidateList;
class ModifiersPool;
class Statement;
class SymbolTable;
class Variable;
/**
* Converts a FunctionCall in the IR to a set of statements to be injected ahead of the function
* call, and a replacement expression. Can also detect cases where inlining isn't cleanly possible
* (e.g. return statements nested inside of a loop construct). The inliner isn't able to guarantee
* identical-to-GLSL execution order if the inlined function has visible side effects.
*/
class Inliner {
public:
Inliner(const Context* context) : fContext(context) {}
void reset();
/** Inlines any eligible functions that are found. Returns true if any changes are made. */
bool analyze(const std::vector<std::unique_ptr<ProgramElement>>& elements,
std::shared_ptr<SymbolTable> symbols,
ProgramUsage* usage);
private:
using VariableRewriteMap = std::unordered_map<const Variable*, std::unique_ptr<Expression>>;
enum class ReturnComplexity {
kSingleSafeReturn,
kScopedReturns,
kEarlyReturns,
};
const Program::Settings& settings() const { return fContext->fConfig->fSettings; }
void buildCandidateList(const std::vector<std::unique_ptr<ProgramElement>>& elements,
std::shared_ptr<SymbolTable> symbols, ProgramUsage* usage,
InlineCandidateList* candidateList);
std::unique_ptr<Expression> inlineExpression(int line,
VariableRewriteMap* varMap,
SymbolTable* symbolTableForExpression,
const Expression& expression);
std::unique_ptr<Statement> inlineStatement(int line,
VariableRewriteMap* varMap,
SymbolTable* symbolTableForStatement,
std::unique_ptr<Expression>* resultExpr,
ReturnComplexity returnComplexity,
const Statement& statement,
bool isBuiltinCode);
/**
* Searches the rewrite map for an rewritten Variable* for the passed-in one. Asserts if the
* rewrite map doesn't contain the variable, or contains a different type of expression.
*/
static const Variable* RemapVariable(const Variable* variable,
const VariableRewriteMap* varMap);
/** Determines if a given function has multiple and/or early returns. */
static ReturnComplexity GetReturnComplexity(const FunctionDefinition& funcDef);
using InlinabilityCache = std::unordered_map<const FunctionDeclaration*, bool>;
bool candidateCanBeInlined(const InlineCandidate& candidate,
const ProgramUsage& usage,
InlinabilityCache* cache);
using FunctionSizeCache = std::unordered_map<const FunctionDeclaration*, int>;
int getFunctionSize(const FunctionDeclaration& fnDecl, FunctionSizeCache* cache);
/**
* Processes the passed-in FunctionCall expression. The FunctionCall expression should be
* replaced with `fReplacementExpr`. If non-null, `fInlinedBody` should be inserted immediately
* above the statement containing the inlined expression.
*/
struct InlinedCall {
std::unique_ptr<Block> fInlinedBody;
std::unique_ptr<Expression> fReplacementExpr;
};
InlinedCall inlineCall(FunctionCall*,
std::shared_ptr<SymbolTable>,
const ProgramUsage&,
const FunctionDeclaration* caller);
/** Adds a scope to inlined bodies returned by `inlineCall`, if one is required. */
void ensureScopedBlocks(Statement* inlinedBody, Statement* parentStmt);
/** Checks whether inlining is viable for a FunctionCall, modulo recursion and function size. */
bool isSafeToInline(const FunctionDefinition* functionDef, const ProgramUsage& usage);
const Context* fContext = nullptr;
int fInlinedStatementCounter = 0;
};
} // namespace SkSL
#endif // SKSL_INLINER