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// Copyright 2021 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 "Pragma.hpp"
#include "PragmaInternals.hpp"
#include "Debug.hpp"
// The CLANG_NO_SANITIZE_MEMORY macro suppresses MemorySanitizer checks for
// use-of-uninitialized-data. It is used to decorate functions with known
// false positives.
#ifdef __clang__
# define CLANG_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory))
#else
# define CLANG_NO_SANITIZE_MEMORY
#endif
namespace {
struct PragmaState
{
bool memorySanitizerInstrumentation = true;
bool initializeLocalVariables = false;
int optimizationLevel = 2; // Default
};
// The initialization of static thread-local data is not observed by MemorySanitizer
// when inside a shared library, leading to false-positive use-of-uninitialized-data
// errors: https://github.com/google/sanitizers/issues/1409
// We work around this by assigning an initial value to it ourselves on first use.
// Note that since the flag to check whether this initialization has already been
// done is itself a static thread-local, we must suppress the MemorySanitizer check
// with a function attribute.
CLANG_NO_SANITIZE_MEMORY PragmaState &getPragmaState()
{
static thread_local bool initialized = false;
static thread_local PragmaState state;
if(!initialized)
{
state = {};
initialized = true;
}
return state;
}
} // namespace
namespace rr {
void Pragma(BooleanPragmaOption option, bool enable)
{
PragmaState &state = ::getPragmaState();
switch(option)
{
case MemorySanitizerInstrumentation:
state.memorySanitizerInstrumentation = enable;
break;
case InitializeLocalVariables:
state.initializeLocalVariables = enable;
break;
default:
UNSUPPORTED("Unknown Boolean pragma option %d", int(option));
}
}
void Pragma(IntegerPragmaOption option, int value)
{
PragmaState &state = ::getPragmaState();
switch(option)
{
case OptimizationLevel:
state.optimizationLevel = value;
break;
default:
UNSUPPORTED("Unknown integer pragma option %d", int(option));
}
}
bool getPragmaState(BooleanPragmaOption option)
{
PragmaState &state = ::getPragmaState();
switch(option)
{
case MemorySanitizerInstrumentation:
return state.memorySanitizerInstrumentation;
case InitializeLocalVariables:
return state.initializeLocalVariables;
default:
UNSUPPORTED("Unknown Boolean pragma option %d", int(option));
return false;
}
}
int getPragmaState(IntegerPragmaOption option)
{
PragmaState &state = ::getPragmaState();
switch(option)
{
case OptimizationLevel:
return state.optimizationLevel;
default:
UNSUPPORTED("Unknown integer pragma option %d", int(option));
return 0;
}
}
ScopedPragma::ScopedPragma(BooleanPragmaOption option, bool enable)
{
oldState = BooleanPragma{ option, getPragmaState(option) };
Pragma(option, enable);
}
ScopedPragma::ScopedPragma(IntegerPragmaOption option, int value)
{
oldState = IntegerPragma{ option, getPragmaState(option) };
Pragma(option, value);
}
ScopedPragma::~ScopedPragma()
{
if(std::holds_alternative<BooleanPragma>(oldState))
{
auto &restore = std::get<BooleanPragma>(oldState);
Pragma(restore.option, restore.enable);
}
else
{
auto &restore = std::get<IntegerPragma>(oldState);
Pragma(restore.option, restore.value);
}
}
} // namespace rr