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Make enum symbol tables standalone (no parent table)

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Fixes cases where symbol lookup inside an enum would be allowed to
resolve things from the outer scope.

Bug: oss-fuzz:24674
Change-Id: I841224a7449d2a4f97e41a9d2edd4631ba888a7d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/315602
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
This commit is contained in:
Brian Osman 2020-09-08 10:34:30 -04:00 committed by Skia Commit-Bot
parent d849a75ad3
commit 1313d1aa7a
5 changed files with 52 additions and 43 deletions
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75
src/sksl/SkSLIRGenerator.cpp
View File

@ -1265,7 +1265,8 @@ void IRGenerator::convertEnum(const ASTNode& e) {
ASTNode::TypeData(e.getString(), false, false));
const Type* type = this->convertType(enumType);
Modifiers modifiers(layout, Modifiers::kConst_Flag);
AutoSymbolTable table(this);
std::shared_ptr<SymbolTable> oldTable = fSymbolTable;
fSymbolTable = std::make_shared<SymbolTable>(fSymbolTable);
for (auto iter = e.begin(); iter != e.end(); ++iter) {
const ASTNode& child = *iter;
SkASSERT(child.fKind == ASTNode::Kind::kEnumCase);
@ -1273,10 +1274,12 @@ void IRGenerator::convertEnum(const ASTNode& e) {
if (child.begin() != child.end()) {
value = this->convertExpression(*child.begin());
if (!value) {
fSymbolTable = oldTable;
return;
}
if (!this->getConstantInt(*value, &currentValue)) {
fErrors.error(value->fOffset, "enum value must be a constant integer");
fSymbolTable = oldTable;
return;
}
}
@ -1287,8 +1290,11 @@ void IRGenerator::convertEnum(const ASTNode& e) {
Variable::kGlobal_Storage, value.get()));
fSymbolTable->takeOwnershipOfIRNode(std::move(value));
}
// Now we orphanize the Enum's symbol table, so that future lookups in it are strict
fSymbolTable->fParent = nullptr;
fProgramElements->push_back(std::unique_ptr<ProgramElement>(
new Enum(e.fOffset, e.getString(), fSymbolTable, fIsBuiltinCode)));
fSymbolTable = oldTable;
}
const Type* IRGenerator::convertType(const ASTNode& type) {
@ -2626,38 +2632,41 @@ std::unique_ptr<Expression> IRGenerator::getCap(int offset, String name) {
found->second.literal(fContext, offset)));
}
std::unique_ptr<Expression> IRGenerator::findEnumRef(
int offset,
const Type& type,
StringFragment field,
std::vector<std::unique_ptr<ProgramElement>>& elements) {
for (const auto& e : elements) {
if (e->kind() == ProgramElement::Kind::kEnum && type.name() == e->as<Enum>().fTypeName) {
std::shared_ptr<SymbolTable> old = fSymbolTable;
fSymbolTable = e->as<Enum>().fSymbols;
std::unique_ptr<Expression> result = convertIdentifier(ASTNode(&fFile->fNodes, offset,
ASTNode::Kind::kIdentifier,
field));
if (result) {
const Variable& v = result->as<VariableReference>().fVariable;
SkASSERT(v.fInitialValue);
result = std::make_unique<IntLiteral>(
offset, v.fInitialValue->as<IntLiteral>().fValue, &type);
}
fSymbolTable = old;
return result;
}
}
return nullptr;
}
std::unique_ptr<Expression> IRGenerator::convertTypeField(int offset, const Type& type,
StringFragment field) {
std::unique_ptr<Expression> result = this->findEnumRef(offset, type, field, *fProgramElements);
if (fInherited && !result) {
result = this->findEnumRef(offset, type, field, *fInherited);
// Find the Enum element that this type refers to (if any)
auto findEnum = [=](std::vector<std::unique_ptr<ProgramElement>>& elements) -> ProgramElement* {
for (const auto& e : elements) {
if (e->is<Enum>() && type.name() == e->as<Enum>().fTypeName) {
return e.get();
}
}
return nullptr;
};
const ProgramElement* enumElement = findEnum(*fProgramElements);
if (fInherited && !enumElement) {
enumElement = findEnum(*fInherited);
}
if (!result) {
if (enumElement) {
// We found the Enum element. Look for 'field' as a member.
std::shared_ptr<SymbolTable> old = fSymbolTable;
fSymbolTable = enumElement->as<Enum>().fSymbols;
std::unique_ptr<Expression> result = convertIdentifier(
ASTNode(&fFile->fNodes, offset, ASTNode::Kind::kIdentifier, field));
if (result) {
const Variable& v = result->as<VariableReference>().fVariable;
SkASSERT(v.fInitialValue);
result = std::make_unique<IntLiteral>(
offset, v.fInitialValue->as<IntLiteral>().fValue, &type);
} else {
fErrors.error(offset,
"type '" + type.fName + "' does not have a field named '" + field + "'");
}
fSymbolTable = old;
return result;
} else {
// No Enum element? Check the intrinsics, clone it into the program, try again.
auto found = fIntrinsics->find(type.fName);
if (found != fIntrinsics->end()) {
SkASSERT(!found->second.fAlreadyIncluded);
@ -2665,10 +2674,10 @@ std::unique_ptr<Expression> IRGenerator::convertTypeField(int offset, const Type
fProgramElements->push_back(found->second.fIntrinsic->clone());
return this->convertTypeField(offset, type, field);
}
fErrors.error(offset, "type '" + type.fName + "' does not have a field named '" + field +
"'");
fErrors.error(offset,
"type '" + type.fName + "' does not have a field named '" + field + "'");
return nullptr;
}
return result;
}
std::unique_ptr<Expression> IRGenerator::convertIndexExpression(const ASTNode& index) {

4
src/sksl/SkSLIRGenerator.h
View File

@ -144,10 +144,6 @@ private:
std::unique_ptr<Expression> convertFieldExpression(const ASTNode& expression);
std::unique_ptr<Expression> convertIndexExpression(const ASTNode& expression);
std::unique_ptr<Expression> convertPostfixExpression(const ASTNode& expression);
std::unique_ptr<Expression> findEnumRef(int offset,
const Type& type,
StringFragment field,
std::vector<std::unique_ptr<ProgramElement>>& elements);
std::unique_ptr<Expression> convertTypeField(int offset, const Type& type,
StringFragment field);
std::unique_ptr<Expression> convertField(std::unique_ptr<Expression> base,

10
src/sksl/SkSLRehydrator.cpp
View File

@ -265,7 +265,7 @@ std::unique_ptr<ProgramElement> Rehydrator::element() {
switch (kind) {
case Rehydrator::kEnum_Command: {
StringFragment typeName = this->readString();
std::shared_ptr<SymbolTable> symbols = this->symbolTable();
std::shared_ptr<SymbolTable> symbols = this->symbolTable(/*inherit=*/false);
for (auto& s : symbols->fOwnedSymbols) {
SkASSERT(s->kind() == Symbol::Kind::kVariable);
Variable& v = (Variable&) *s;
@ -560,14 +560,16 @@ std::unique_ptr<Expression> Rehydrator::expression() {
}
}
std::shared_ptr<SymbolTable> Rehydrator::symbolTable() {
std::shared_ptr<SymbolTable> Rehydrator::symbolTable(bool inherit) {
int command = this->readU8();
if (command == kVoid_Command) {
return nullptr;
}
SkASSERT(command == kSymbolTable_Command);
uint16_t ownedCount = this->readU16();
std::shared_ptr<SymbolTable> result(new SymbolTable(fSymbolTable));
std::shared_ptr<SymbolTable> oldTable = fSymbolTable;
std::shared_ptr<SymbolTable> result = inherit ? std::make_shared<SymbolTable>(fSymbolTable)
: std::make_shared<SymbolTable>(fErrors);
fSymbolTable = result;
std::vector<const Symbol*> ownedSymbols;
ownedSymbols.reserve(ownedCount);
@ -582,7 +584,7 @@ std::shared_ptr<SymbolTable> Rehydrator::symbolTable() {
int index = this->readU16();
fSymbolTable->addWithoutOwnership(name, ownedSymbols[index]);
}
fSymbolTable = fSymbolTable->fParent;
fSymbolTable = oldTable;
return result;
}

4
src/sksl/SkSLRehydrator.h
View File

@ -143,6 +143,7 @@ public:
Rehydrator(Context* context, std::shared_ptr<SymbolTable> symbolTable,
ErrorReporter* errorReporter, const uint8_t* src, size_t length)
: fContext(*context)
, fErrors(errorReporter)
, fSymbolTable(std::move(symbolTable))
, fStart(src)
SkDEBUGCODE(, fEnd(fStart + length)) {
@ -154,7 +155,7 @@ public:
std::vector<std::unique_ptr<ProgramElement>> elements();
std::shared_ptr<SymbolTable> symbolTable();
std::shared_ptr<SymbolTable> symbolTable(bool inherit = true);
private:
int8_t readS8() {
@ -224,6 +225,7 @@ private:
const Type* type();
Context& fContext;
ErrorReporter* fErrors;
std::shared_ptr<SymbolTable> fSymbolTable;
std::vector<const Symbol*> fSymbols;

2
src/sksl/ir/SkSLSymbolTable.h
View File

@ -63,7 +63,7 @@ public:
std::unordered_map<StringFragment, const Symbol*>::iterator end();
const std::shared_ptr<SymbolTable> fParent;
std::shared_ptr<SymbolTable> fParent;
std::vector<std::unique_ptr<const Symbol>> fOwnedSymbols;