blob: 5de60d1da947e56430b5c32a1511e65c04968f53 [file] [log] [blame]
* Copyright 2010, The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <list>
#include <stack>
#include "clang/AST/StmtVisitor.h"
#include "slang_assert.h"
#include "slang_rs_export_type.h"
namespace clang {
class Expr;
class Stmt;
namespace slang {
// Recursive check
bool HasRSObjectType(const clang::Type *T);
// This class provides the overall reference counting mechanism for handling
// local variables of RS object types (rs_font, rs_allocation, ...). This
// class ensures that appropriate functions (rsSetObject, rsClearObject) are
// called at proper points in the object's lifetime.
// 1) Each local object of appropriate type must be zero-initialized to
// prevent corruption during subsequent rsSetObject()/rsClearObject() calls.
// 2) Assignments using these types must also be converted into the
// appropriate (possibly a series of) rsSetObject() calls.
// 3) Finally, rsClearObject() must be called for each local object when it goes
// out of scope.
class RSObjectRefCount : public clang::StmtVisitor<RSObjectRefCount> {
class Scope {
clang::CompoundStmt *mCS; // Associated compound statement ({ ... })
clang::Stmt *mCurrent; // The statement currently being analyzed
std::list<clang::VarDecl*> mRSO; // Declared RS objects in this scope (but
// not any scopes nested)
explicit Scope(clang::CompoundStmt *CS) : mCS(CS) {
bool hasRSObject() const { return !mRSO.empty(); }
inline void addRSObject(clang::VarDecl* VD) {
void ReplaceRSObjectAssignment(clang::BinaryOperator *AS);
void AppendRSObjectInit(clang::VarDecl *VD,
clang::DeclStmt *DS,
DataType DT,
clang::Expr *InitExpr);
// Inserts rsClearObject() calls at the end and at all exiting points of the
// current scope. At each statement that exits the current scope -- e.g.,
// a return, break, or continue statement in the current or a nested scope
// -- rsClearObject() calls are inserted for local variables defined in the
// current scope before that point.
// Note goto statements are not handled. (See the DestructorVisitor class in
// the .cpp file.)
// Also note this function is called for every nested scope. As a result, for a
// return statement, each rsObject declared in all its (nested) enclosing
// scopes would have a rsClearObject() call properly inserted before
// the return statement.
void InsertLocalVarDestructors();
// Sets the current statement being analyzed
void setCurrentStmt(clang::Stmt *S) { mCurrent = S; }
// Inserts a statement before the current statement
void InsertStmt(const clang::ASTContext &C, clang::Stmt *NewStmt);
// Replaces the current statement with NewStmt;
void ReplaceStmt(const clang::ASTContext &C, clang::Stmt *NewStmt);
// Replaces OldExpr with NewExpr in the current statement
void ReplaceExpr(const clang::ASTContext& C, clang::Expr* OldExpr,
clang::Expr* NewExpr);
static clang::Stmt *ClearRSObject(clang::VarDecl *VD,
clang::DeclContext *DC);
clang::ASTContext &mCtx;
std::deque<Scope*> mScopeStack; // A deque used as a stack to store scopes, but also
// accessed through its iterator in read-only mode.
clang::DeclContext* mCurrentDC;
bool RSInitFD;
unsigned mTempID; // A unique id that can be used to distinguish temporary variables
// RSSetObjectFD and RSClearObjectFD holds FunctionDecl of rsSetObject()
// and rsClearObject() in the current ASTContext.
static clang::FunctionDecl *RSSetObjectFD[];
static clang::FunctionDecl *RSClearObjectFD[];
inline bool emptyScope() const { return mScopeStack.empty(); }
inline Scope *getCurrentScope() {
return mScopeStack.back();
// Returns the next available unique id for temporary variables
unsigned getNextID() { return mTempID++; }
// Initialize RSSetObjectFD and RSClearObjectFD.
static void GetRSRefCountingFunctions(clang::ASTContext &C);
// Return false if the type of variable declared in VD does not contain
// an RS object type.
static bool InitializeRSObject(clang::VarDecl *VD,
DataType *DT,
clang::Expr **InitExpr);
// Return an empty list initializer expression at the appropriate location.
// This construct can then be used to cheaply construct a zero-initializer
// for any RenderScript objects (like rs_allocation) or rs_matrix* types
// (possibly even embedded within other types). These types are expected to
// be zero-initialized always, and so we can use this helper to ensure that
// they at least have an empty initializer.
static clang::Expr *CreateEmptyInitListExpr(
clang::ASTContext &C,
const clang::SourceLocation &Loc);
// Given a return statement RS that returns an rsObject, creates a temporary
// variable, and sets it to the original return expression using rsSetObject().
// Creates a new return statement that returns the temporary variable.
// Returns a new compound statement that contains the new variable declaration,
// the rsSetOjbect() call, and the new return statement.
static clang::CompoundStmt* CreateRetStmtWithTempVar(
clang::ASTContext& C,
clang::DeclContext* DC,
clang::ReturnStmt* RS,
const unsigned id);
explicit RSObjectRefCount(clang::ASTContext &C)
: mCtx(C), RSInitFD(false), mTempID(0) {
void Init() {
if (!RSInitFD) {
RSInitFD = true;
static clang::FunctionDecl *GetRSSetObjectFD(DataType DT) {
if (DT >= 0 && DT < DataTypeMax) {
return RSSetObjectFD[DT];
} else {
slangAssert(false && "incorrect type");
return nullptr;
static clang::FunctionDecl *GetRSSetObjectFD(const clang::Type *T) {
return GetRSSetObjectFD(RSExportPrimitiveType::GetRSSpecificType(T));
static clang::FunctionDecl *GetRSClearObjectFD(DataType DT) {
if (DT >= 0 && DT < DataTypeMax) {
return RSClearObjectFD[DT];
} else {
slangAssert(false && "incorrect type");
return nullptr;
static clang::FunctionDecl *GetRSClearObjectFD(const clang::Type *T) {
return GetRSClearObjectFD(RSExportPrimitiveType::GetRSSpecificType(T));
void SetDeclContext(clang::DeclContext* DC) { mCurrentDC = DC; }
clang::DeclContext* GetDeclContext() const { return mCurrentDC; }
void VisitStmt(clang::Stmt *S);
void VisitCallExpr(clang::CallExpr *CE);
void VisitDeclStmt(clang::DeclStmt *DS);
void VisitCompoundStmt(clang::CompoundStmt *CS);
void VisitBinAssign(clang::BinaryOperator *AS);
void VisitReturnStmt(clang::ReturnStmt *RS);
// We believe that RS objects are never involved in CompoundAssignOperator.
// I.e., rs_allocation foo; foo += bar;
// Emit a global destructor to clean up RS objects.
clang::FunctionDecl *CreateStaticGlobalDtor();
} // namespace slang