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// Copyright 2016 The SwiftShader Authors. All Rights Reserved.
//
// 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
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "ValidateSwitch.h"
#include "ParseHelper.h"
bool ValidateSwitch::validate(TBasicType switchType, TParseContext *context,
TIntermAggregate *statementList, const TSourceLoc &loc)
{
ValidateSwitch validate(switchType, context);
ASSERT(statementList);
statementList->traverse(&validate);
return validate.validateInternal(loc);
}
ValidateSwitch::ValidateSwitch(TBasicType switchType, TParseContext *context)
: TIntermTraverser(true, false, true),
mSwitchType(switchType),
mContext(context),
mCaseTypeMismatch(false),
mFirstCaseFound(false),
mStatementBeforeCase(false),
mLastStatementWasCase(false),
mControlFlowDepth(0),
mCaseInsideControlFlow(false),
mDefaultCount(0),
mDuplicateCases(false)
{}
void ValidateSwitch::visitSymbol(TIntermSymbol *)
{
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
}
void ValidateSwitch::visitConstantUnion(TIntermConstantUnion *)
{
// Conditions of case labels are not traversed, so this is some other constant
// Could be just a statement like "0;"
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
}
bool ValidateSwitch::visitBinary(Visit, TIntermBinary *)
{
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
return true;
}
bool ValidateSwitch::visitUnary(Visit, TIntermUnary *)
{
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
return true;
}
bool ValidateSwitch::visitSelection(Visit visit, TIntermSelection *)
{
if (visit == PreVisit)
++mControlFlowDepth;
if (visit == PostVisit)
--mControlFlowDepth;
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
return true;
}
bool ValidateSwitch::visitSwitch(Visit, TIntermSwitch *)
{
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
// Don't go into nested switch statements
return false;
}
bool ValidateSwitch::visitCase(Visit, TIntermCase *node)
{
const char *nodeStr = node->hasCondition() ? "case" : "default";
if (mControlFlowDepth > 0)
{
mContext->error(node->getLine(), "label statement nested inside control flow", nodeStr);
mCaseInsideControlFlow = true;
}
mFirstCaseFound = true;
mLastStatementWasCase = true;
if (!node->hasCondition())
{
++mDefaultCount;
if (mDefaultCount > 1)
{
mContext->error(node->getLine(), "duplicate default label", nodeStr);
}
}
else
{
TIntermConstantUnion *condition = node->getCondition()->getAsConstantUnion();
if (condition == nullptr)
{
// This can happen in error cases.
return false;
}
TBasicType conditionType = condition->getBasicType();
if (conditionType != mSwitchType)
{
mContext->error(condition->getLine(),
"case label type does not match switch init-expression type", nodeStr);
mCaseTypeMismatch = true;
}
if (conditionType == EbtInt)
{
int iConst = condition->getIConst(0);
if (mCasesSigned.find(iConst) != mCasesSigned.end())
{
mContext->error(condition->getLine(), "duplicate case label", nodeStr);
mDuplicateCases = true;
}
else
{
mCasesSigned.insert(iConst);
}
}
else if (conditionType == EbtUInt)
{
unsigned int uConst = condition->getUConst(0);
if (mCasesUnsigned.find(uConst) != mCasesUnsigned.end())
{
mContext->error(condition->getLine(), "duplicate case label", nodeStr);
mDuplicateCases = true;
}
else
{
mCasesUnsigned.insert(uConst);
}
}
// Other types are possible only in error cases, where the error has already been generated
// when parsing the case statement.
}
// Don't traverse the condition of the case statement
return false;
}
bool ValidateSwitch::visitAggregate(Visit visit, TIntermAggregate *)
{
if (getParentNode() != nullptr)
{
// This is not the statementList node, but some other node.
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
}
return true;
}
bool ValidateSwitch::visitLoop(Visit visit, TIntermLoop *)
{
if (visit == PreVisit)
++mControlFlowDepth;
if (visit == PostVisit)
--mControlFlowDepth;
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
return true;
}
bool ValidateSwitch::visitBranch(Visit, TIntermBranch *)
{
if (!mFirstCaseFound)
mStatementBeforeCase = true;
mLastStatementWasCase = false;
return true;
}
bool ValidateSwitch::validateInternal(const TSourceLoc &loc)
{
if (mStatementBeforeCase)
{
mContext->error(loc,
"statement before the first label", "switch");
}
if (mLastStatementWasCase)
{
mContext->error(loc,
"no statement between the last label and the end of the switch statement", "switch");
}
return !mStatementBeforeCase && !mLastStatementWasCase && !mCaseInsideControlFlow &&
!mCaseTypeMismatch && mDefaultCount <= 1 && !mDuplicateCases;
}