coroutine.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2013 CERN
 * Copyright (C) 2016-2020 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * @author Tomasz Wlostowski <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
#ifndef __COROUTINE_H
#define __COROUTINE_H
 
#include <cassert>
#include <cstdlib>
#include <type_traits>
 
#ifdef KICAD_USE_VALGRIND
#include <valgrind/valgrind.h>
#endif
#ifdef KICAD_SANITIZE_THREADS
#include <sanitizer/tsan_interface.h>
#endif
#ifdef KICAD_SANITIZE_ADDRESS
#include <sanitizer/asan_interface.h>
#endif
 
#include <libcontext.h>
#include <functional>
#include <optional>
#include <memory>
#include <advanced_config.h>
 
#include <trace_helpers.h>
#include <wx/log.h>
 
#ifdef _WIN32
#include <windows.h>
#else // Linux, BSD, MacOS
#include <unistd.h> // getpagesize
#include <sys/mman.h> // mmap, mprotect, munmap
#endif
 
template <typename ReturnType, typename ArgType>
class COROUTINE
{
private:
 class CALL_CONTEXT;
 
 struct INVOCATION_ARGS
 {
 enum
 {
 FROM_ROOT, // a stub was called/a coroutine was resumed from the main-stack context
 FROM_ROUTINE, // a stub was called/a coroutine was resumed from a coroutine context
 CONTINUE_AFTER_ROOT // a function sent a request to invoke a function on the main
 // stack context
 } type; // invocation type
 COROUTINE* destination; // stores the coroutine pointer for the stub OR the coroutine
 // ptr for the coroutine to be resumed if a
 // root(main-stack)-call-was initiated.
 CALL_CONTEXT* context; // pointer to the call context of the current callgraph this
 // call context holds a reference to the main stack context
 };
 
 struct CONTEXT_T
 {
 libcontext::fcontext_t ctx; // The context itself
#ifdef KICAD_SANITIZE_THREADS
 void* tsan_fiber; // The TSAN fiber for this context
 bool own_tsan_fiber; // Do we own this TSAN fiber? (we only delete fibers we own)
#endif
 
 CONTEXT_T() :
 ctx( nullptr )
#ifdef KICAD_SANITIZE_THREADS
 ,tsan_fiber( nullptr )
 ,own_tsan_fiber( true )
#endif
 {}
 
 ~CONTEXT_T()
 {
#ifdef KICAD_SANITIZE_THREADS
 // Only destroy the fiber when we own it
 if( own_tsan_fiber )
 __tsan_destroy_fiber( tsan_fiber );
#endif
 }
 };
 
 class CALL_CONTEXT
 {
 public:
 CALL_CONTEXT() :
 m_mainStackContext( nullptr )
 {
 }
 
 ~CALL_CONTEXT()
 {
 if( m_mainStackContext )
 libcontext::release_fcontext( m_mainStackContext->ctx );
 }
 
 
 void SetMainStack( CONTEXT_T* aStack )
 {
 m_mainStackContext = aStack;
 }
 
 void RunMainStack( COROUTINE* aCor, std::function<void()> aFunc )
 {
 m_mainStackFunction = std::move( aFunc );
 INVOCATION_ARGS args{ INVOCATION_ARGS::CONTINUE_AFTER_ROOT, aCor, this };
 
#ifdef KICAD_SANITIZE_THREADS
 // Tell TSAN we are changing fibers
 __tsan_switch_to_fiber( m_mainStackContext->tsan_fiber, 0 );
#endif
 
 libcontext::jump_fcontext( &( aCor->m_callee.ctx ), m_mainStackContext->ctx,
 reinterpret_cast<intptr_t>( &args ) );
 }
 
 void Continue( INVOCATION_ARGS* args )
 {
 while( args->type == INVOCATION_ARGS::CONTINUE_AFTER_ROOT )
 {
 m_mainStackFunction();
 args->type = INVOCATION_ARGS::FROM_ROOT;
 args = args->destination->doResume( args );
 }
 }
 
 private:
 CONTEXT_T* m_mainStackContext;
 std::function<void()> m_mainStackFunction;
 };
 
public:
 COROUTINE() :
 COROUTINE( nullptr )
 {
 }
 
 template <class T>
 COROUTINE( T* object, ReturnType(T::*ptr)( ArgType ) ) :
 COROUTINE( std::bind( ptr, object, std::placeholders::_1 ) )
 {
 }
 
 COROUTINE( std::function<ReturnType( ArgType )> aEntry ) :
 m_func( std::move( aEntry ) ),
 m_running( false ),
 m_args( nullptr ),
 m_caller(),
 m_callContext( nullptr ),
 m_callee(),
 m_retVal( 0 )
#ifdef KICAD_USE_VALGRIND
 ,m_valgrind_stack( 0 )
#endif
#ifdef KICAD_SANITIZE_ADDRESS
 ,asan_stack( nullptr )
#endif
 {
 m_stacksize = ADVANCED_CFG::GetCfg().m_CoroutineStackSize;
 }
 
 ~COROUTINE()
 {
#ifdef KICAD_USE_VALGRIND
 VALGRIND_STACK_DEREGISTER( m_valgrind_stack );
#endif
 
 if( m_caller.ctx )
 libcontext::release_fcontext( m_caller.ctx );
 
 if( m_callee.ctx )
 libcontext::release_fcontext( m_callee.ctx );
 }
 
public:
 void KiYield()
 {
 jumpOut();
 }
 
 void KiYield( ReturnType& aRetVal )
 {
 m_retVal = aRetVal;
 jumpOut();
 }
 
 void RunMainStack( std::function<void()> func )
 {
 assert( m_callContext );
 m_callContext->RunMainStack( this, std::move( func ) );
 }
 
 bool Call( ArgType aArg )
 {
 CALL_CONTEXT ctx;
 INVOCATION_ARGS args{ INVOCATION_ARGS::FROM_ROOT, this, &ctx };
 
#ifdef KICAD_SANITIZE_THREADS
 // Get the TSAN fiber for the current stack here
 m_caller.tsan_fiber = __tsan_get_current_fiber();
 m_caller.own_tsan_fiber = false;
#endif
 
 wxLogTrace( kicadTraceCoroutineStack, "COROUTINE::Call (from root)" );
 
 ctx.Continue( doCall( &args, aArg ) );
 
 return Running();
 }
 
 bool Call( const COROUTINE& aCor, ArgType aArg )
 {
 INVOCATION_ARGS args{ INVOCATION_ARGS::FROM_ROUTINE, this, aCor.m_callContext };
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::Call (from routine)" ) );
 
 doCall( &args, aArg );
 // we will not be asked to continue
 
 return Running();
 }
 
 bool Resume()
 {
 CALL_CONTEXT ctx;
 INVOCATION_ARGS args{ INVOCATION_ARGS::FROM_ROOT, this, &ctx };
 
#ifdef KICAD_SANITIZE_THREADS
 // Get the TSAN fiber for the current stack here
 m_caller.tsan_fiber = __tsan_get_current_fiber();
 m_caller.own_tsan_fiber = false;
#endif
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::Resume (from root)" ) );
 
 ctx.Continue( doResume( &args ) );
 
 return Running();
 }
 
 bool Resume( const COROUTINE& aCor )
 {
 INVOCATION_ARGS args{ INVOCATION_ARGS::FROM_ROUTINE, this, aCor.m_callContext };
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::Resume (from routine)" ) );
 
 doResume( &args );
 // we will not be asked to continue
 
 return Running();
 }
 
 const ReturnType& ReturnValue() const
 {
 return m_retVal;
 }
 
 bool Running() const
 {
 return m_running;
 }
 
private:
 INVOCATION_ARGS* doCall( INVOCATION_ARGS* aInvArgs, ArgType aArgs )
 {
 assert( m_func );
 assert( !( m_callee.ctx ) );
 
 m_args = &aArgs;
 
 std::size_t stackSize = m_stacksize;
 void* sp = nullptr;
 
#ifndef LIBCONTEXT_HAS_OWN_STACK
 assert( !m_stack );
 
 const std::size_t systemPageSize = SystemPageSize();
 
 // calculate the correct number of pages to allocate based on request stack size
 std::size_t pages = ( m_stacksize + systemPageSize - 1 ) / systemPageSize;
 
 // we allocate an extra page for the guard
 stackSize = ( pages + 1 ) * systemPageSize;
 
 m_stack.reset( static_cast<char*>( MapMemory( stackSize ) ) );
 m_stack.get_deleter().SetSize( stackSize );
 
 // now configure the first page (by only specifying a single page_size from vp)
 // that will act as the guard page
 // the stack will grow from the end and hopefully never into this guarded region
 GuardMemory( m_stack.get(), systemPageSize );
 
 sp = static_cast<char*>( m_stack.get() ) + stackSize;
 
#ifdef KICAD_USE_VALGRIND
 m_valgrind_stack = VALGRIND_STACK_REGISTER( sp, m_stack.get() );
#endif
#endif
 
#ifdef KICAD_SANITIZE_THREADS
 // Create a new fiber to go with the new context
 m_callee.tsan_fiber = __tsan_create_fiber( 0 );
 m_callee.own_tsan_fiber = true;
 
 __tsan_set_fiber_name( m_callee.tsan_fiber, "Coroutine fiber" );
#endif
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::doCall" ) );
 
 m_callee.ctx = libcontext::make_fcontext( sp, stackSize, callerStub );
 m_running = true;
 
 // off we go!
 return jumpIn( aInvArgs );
 }
 
#ifndef LIBCONTEXT_HAS_OWN_STACK
 struct STACK_DELETER
 {
#ifdef _WIN32
 void SetSize( std::size_t ) {}
 void operator()( void* aMem ) noexcept { ::VirtualFree( aMem, 0, MEM_RELEASE ); }
#else
 std::size_t m_size = 0;
 
 void SetSize( std::size_t aSize ) { m_size = aSize; }
 void operator()( void* aMem ) noexcept { ::munmap( aMem, m_size ); }
#endif
 };
 
 static inline size_t SystemPageSize()
 {
 static std::optional<size_t> systemPageSize;
 if( !systemPageSize.has_value() )
 {
#ifdef _WIN32
 SYSTEM_INFO si;
 ::GetSystemInfo( &si );
 systemPageSize = static_cast<size_t>( si.dwPageSize );
#else
 int size = getpagesize();
 systemPageSize = static_cast<size_t>( size );
#endif
 }
 return systemPageSize.value();
 }
 
 static inline void* MapMemory( size_t aAllocSize )
 {
#ifdef _WIN32
 void* mem = ::VirtualAlloc( 0, aAllocSize, MEM_COMMIT, PAGE_READWRITE );
 if( !mem )
 throw std::bad_alloc();
#else
 void* mem = ::mmap( 0, aAllocSize, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0 );
 if( mem == (void*) -1 )
 throw std::bad_alloc();
#endif
 return mem;
 }
 
 static inline void GuardMemory( void* aAddress, size_t aGuardSize )
 {
#ifdef _WIN32
 DWORD old_prot; // dummy var since the arg cannot be NULL
 BOOL res = ::VirtualProtect( aAddress, aGuardSize,
 PAGE_READWRITE | PAGE_GUARD, &old_prot );
#else
 bool res = ( 0 == ::mprotect( aAddress, aGuardSize, PROT_NONE ) );
#endif
 if( !res )
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::GuardMemory has failes" ) );
 }
#endif // LIBCONTEXT_HAS_OWN_STACK
 
 INVOCATION_ARGS* doResume( INVOCATION_ARGS* args )
 {
 return jumpIn( args );
 }
 
 /* real entry point of the coroutine */
 static void callerStub( intptr_t aData )
 {
 INVOCATION_ARGS& args = *reinterpret_cast<INVOCATION_ARGS*>( aData );
 
 // get pointer to self
 COROUTINE* cor = args.destination;
 cor->m_callContext = args.context;
 
 if( args.type == INVOCATION_ARGS::FROM_ROOT )
 cor->m_callContext->SetMainStack( &cor->m_caller );
 
 // call the coroutine method
 cor->m_retVal = cor->m_func( *(cor->m_args) );
 cor->m_running = false;
 
 // go back to wherever we came from.
 cor->jumpOut();
 }
 
 INVOCATION_ARGS* jumpIn( INVOCATION_ARGS* args )
 {
#ifdef KICAD_SANITIZE_THREADS
 // Tell TSAN we are changing fibers to the callee
 __tsan_switch_to_fiber( m_callee.tsan_fiber, 0 );
#endif
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::jumpIn" ) );
 
 args = reinterpret_cast<INVOCATION_ARGS*>(
 libcontext::jump_fcontext( &( m_caller.ctx ), m_callee.ctx,
 reinterpret_cast<intptr_t>( args ) )
 );
 
 return args;
 }
 
 void jumpOut()
 {
 INVOCATION_ARGS args{ INVOCATION_ARGS::FROM_ROUTINE, nullptr, nullptr };
 INVOCATION_ARGS* ret;
 
#ifdef KICAD_SANITIZE_THREADS
 // Tell TSAN we are changing fibers back to the caller
 __tsan_switch_to_fiber( m_caller.tsan_fiber, 0 );
#endif
 
 wxLogTrace( kicadTraceCoroutineStack, wxT( "COROUTINE::jumpOut" ) );
 
 ret = reinterpret_cast<INVOCATION_ARGS*>(
 libcontext::jump_fcontext( &( m_callee.ctx ), m_caller.ctx,
 reinterpret_cast<intptr_t>( &args ) )
 );
 
 m_callContext = ret->context;
 
 if( ret->type == INVOCATION_ARGS::FROM_ROOT )
 {
 m_callContext->SetMainStack( &m_caller );
 }
 }
 
#ifndef LIBCONTEXT_HAS_OWN_STACK
 std::unique_ptr<char[], struct STACK_DELETER> m_stack;
#endif
 
 int m_stacksize;
 
 std::function<ReturnType( ArgType )> m_func;
 
 bool m_running;
 
 typename std::remove_reference<ArgType>::type* m_args;
 
 CONTEXT_T m_caller;
 
 CALL_CONTEXT* m_callContext;
 
 CONTEXT_T m_callee;
 
 ReturnType m_retVal;
 
#ifdef KICAD_USE_VALGRIND
 uint32_t m_valgrind_stack;
#endif
#ifdef KICAD_SANITIZE_ADDRESS
 void* asan_stack;
#endif
};
 
#endif