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Codechange: use std::allocator over malloc/free for Squirrel memory management

pull/13331/head
Rubidium 2025-02-21 18:42:49 +01:00 committed by rubidium42
parent c5e01c1907
commit 3790f29156
3 changed files with 60 additions and 105 deletions
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1
src/3rdparty/squirrel/squirrel/CMakeLists.txt vendored
View File

@ -13,7 +13,6 @@ add_files(
sqfuncstate.h
sqlexer.cpp
sqlexer.h
sqmem.cpp
sqobject.cpp
sqobject.h
sqopcodes.h

18
src/3rdparty/squirrel/squirrel/sqmem.cpp vendored
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@ -1,18 +0,0 @@
/*
* see copyright notice in squirrel.h
*/
#include "../../../stdafx.h"
#include "sqpcheader.h"
#include "../../../core/alloc_func.hpp"
#include "../../../safeguards.h"
#ifdef SQUIRREL_DEFAULT_ALLOCATOR
void *sq_vm_malloc(SQUnsignedInteger size) { return MallocT<char>((size_t)size); }
void *sq_vm_realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size) { return ReallocT<char>(static_cast<char*>(p), (size_t)size); }
void sq_vm_free(void *p, SQUnsignedInteger size) { free(p); }
#endif

146
src/script/squirrel.cpp
View File

@ -10,6 +10,7 @@
#include "../stdafx.h"
#include "../debug.h"
#include "squirrel_std.hpp"
#include "../error_func.h"
#include "../fileio_func.h"
#include "../string_func.h"
#include "script_fatalerror.hpp"
@ -17,15 +18,8 @@
#include <sqstdaux.h>
#include <../squirrel/sqpcheader.h>
#include <../squirrel/sqvm.h>
#include "../core/alloc_func.hpp"
/**
* In the memory allocator for Squirrel we want to directly use malloc/realloc, so when the OS
* does not have enough memory the game does not go into unrecoverable error mode and kill the
* whole game, but rather let the AI die though then we need to circumvent MallocT/ReallocT.
*
* So no #include "../safeguards.h" here as is required, but after the allocator's implementation.
*/
#include "../safeguards.h"
/*
* If changing the call paths into the scripting engine, define this symbol to enable full debugging of allocations.
@ -34,7 +28,9 @@
*/
struct ScriptAllocator {
size_t allocated_size; ///< Sum of allocated data size
private:
std::allocator<uint8_t> allocator;
size_t allocated_size = 0; ///< Sum of allocated data size
size_t allocation_limit; ///< Maximum this allocator may use before allocations fail
/**
* Whether the error has already been thrown, so to not throw secondary errors in
@ -42,7 +38,7 @@ struct ScriptAllocator {
* throw a Squirrel error so the Squirrel stack can be dumped, however that gets
* allocated by this allocator and then you might end up in an infinite loop.
*/
bool error_thrown;
bool error_thrown = false;
static const size_t SAFE_LIMIT = 0x8000000; ///< 128 MiB, a safe choice for almost any situation
@ -50,42 +46,51 @@ struct ScriptAllocator {
std::map<void *, size_t> allocations;
#endif
void CheckLimit() const
/**
* Checks whether an allocation is allowed by the memory limit set for the script.
* @param requested_size The requested size that was requested to be allocated.
* @throws Script_FatalError When memory may not be allocated (limit reached, except for error handling).
*/
void CheckAllocationAllowed(size_t requested_size)
{
if (this->allocated_size > this->allocation_limit) throw Script_FatalError("Maximum memory allocation exceeded");
/* When an error has been thrown, we are allocating just a bit of memory for the stack trace. */
if (this->error_thrown) return;
if (this->allocated_size + requested_size <= this->allocation_limit) return;
/* Do not allow allocating more than the allocation limit. */
this->error_thrown = true;
std::string msg = fmt::format("Maximum memory allocation exceeded by {} bytes when allocating {} bytes",
this->allocated_size + requested_size - this->allocation_limit, requested_size);
throw Script_FatalError(msg);
}
/**
* Catch all validation for the allocation; did it allocate too much memory according
* to the allocation limit or did the allocation at the OS level maybe fail? In those
* error situations a Script_FatalError is thrown, but once that has been done further
* allocations are allowed to make it possible for Squirrel to throw the error and
* clean everything up.
* @param requested_size The requested size that was requested to be allocated.
* @param p The pointer to the allocated object, or null if allocation failed.
* Internal helper to allocate the given amount of bytes.
* @param requested_size The requested size.
* @return The allocated memory.
* @throws Script_FatalError When memory could not be allocated.
*/
void CheckAllocation(size_t requested_size, void *p)
void *DoAlloc(SQUnsignedInteger requested_size)
{
if (this->allocated_size + requested_size > this->allocation_limit && !this->error_thrown) {
/* Do not allow allocating more than the allocation limit, except when an error is
* already as then the allocation is for throwing that error in Squirrel, the
* associated stack trace information and while cleaning up the AI. */
this->error_thrown = true;
std::string msg = fmt::format("Maximum memory allocation exceeded by {} bytes when allocating {} bytes",
this->allocated_size + requested_size - this->allocation_limit, requested_size);
/* Don't leak the rejected allocation. */
free(p);
throw Script_FatalError(msg);
}
try {
void *p = this->allocator.allocate(requested_size);
assert(p != nullptr);
this->allocated_size += requested_size;
if (p == nullptr) {
#ifdef SCRIPT_DEBUG_ALLOCATIONS
assert(this->allocations.find(p) == this->allocations.end());
this->allocations[p] = requested_size;
#endif
return p;
} catch (const std::bad_alloc &) {
/* The OS did not have enough memory to allocate the object, regardless of the
* limit imposed by OpenTTD on the amount of memory that may be allocated. */
if (this->error_thrown) {
/* The allocation is called in the error handling of a memory allocation
* failure, then not being able to allocate that small amount of memory
* means there is no other choice than to bug out completely. */
MallocError(requested_size);
FatalError("Out of memory. Cannot allocate {} bytes", requested_size);
}
this->error_thrown = true;
@ -94,21 +99,24 @@ struct ScriptAllocator {
}
}
public:
size_t GetAllocatedSize() const { return this->allocated_size; }
void CheckLimit() const
{
if (this->allocated_size > this->allocation_limit) throw Script_FatalError("Maximum memory allocation exceeded");
}
void Reset()
{
assert(this->allocated_size == 0);
this->error_thrown = false;
}
void *Malloc(SQUnsignedInteger size)
{
void *p = malloc(size);
this->CheckAllocation(size, p);
this->allocated_size += size;
#ifdef SCRIPT_DEBUG_ALLOCATIONS
assert(p != nullptr);
assert(this->allocations.find(p) == this->allocations.end());
this->allocations[p] = size;
#endif
return p;
this->CheckAllocationAllowed(size);
return this->DoAlloc(size);
}
void *Realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size)
@ -121,30 +129,11 @@ struct ScriptAllocator {
return nullptr;
}
#ifdef SCRIPT_DEBUG_ALLOCATIONS
assert(this->allocations[p] == oldsize);
this->allocations.erase(p);
#endif
/* Can't use realloc directly because memory limit check.
* If memory exception is thrown, the old pointer is expected
* to be valid for engine cleanup.
*/
void *new_p = malloc(size);
this->CheckAllocationAllowed(size - oldsize);
this->CheckAllocation(size - oldsize, new_p);
/* Memory limit test passed, we can copy data and free old pointer. */
void *new_p = this->DoAlloc(size);
memcpy(new_p, p, std::min(oldsize, size));
free(p);
this->allocated_size -= oldsize;
this->allocated_size += size;
#ifdef SCRIPT_DEBUG_ALLOCATIONS
assert(new_p != nullptr);
assert(this->allocations.find(p) == this->allocations.end());
this->allocations[new_p] = size;
#endif
this->Free(p, oldsize);
return new_p;
}
@ -152,7 +141,7 @@ struct ScriptAllocator {
void Free(void *p, SQUnsignedInteger size)
{
if (p == nullptr) return;
free(p);
this->allocator.deallocate(reinterpret_cast<uint8_t*>(p), size);
this->allocated_size -= size;
#ifdef SCRIPT_DEBUG_ALLOCATIONS
@ -163,10 +152,8 @@ struct ScriptAllocator {
ScriptAllocator()
{
this->allocated_size = 0;
this->allocation_limit = static_cast<size_t>(_settings_game.script.script_max_memory_megabytes) << 20;
if (this->allocation_limit == 0) this->allocation_limit = SAFE_LIMIT; // in case the setting is somehow zero
this->error_thrown = false;
}
~ScriptAllocator()
@ -177,27 +164,16 @@ struct ScriptAllocator {
}
};
/**
* In the memory allocator for Squirrel we want to directly use malloc/realloc, so when the OS
* does not have enough memory the game does not go into unrecoverable error mode and kill the
* whole game, but rather let the AI die though then we need to circumvent MallocT/ReallocT.
* For the rest of this code, the safeguards should be in place though!
*/
#include "../safeguards.h"
ScriptAllocator *_squirrel_allocator = nullptr;
/* See 3rdparty/squirrel/squirrel/sqmem.cpp for the default allocator implementation, which this overrides */
#ifndef SQUIRREL_DEFAULT_ALLOCATOR
void *sq_vm_malloc(SQUnsignedInteger size) { return _squirrel_allocator->Malloc(size); }
void *sq_vm_realloc(void *p, SQUnsignedInteger oldsize, SQUnsignedInteger size) { return _squirrel_allocator->Realloc(p, oldsize, size); }
void sq_vm_free(void *p, SQUnsignedInteger size) { _squirrel_allocator->Free(p, size); }
#endif
size_t Squirrel::GetAllocatedMemory() const noexcept
{
assert(this->allocator != nullptr);
return this->allocator->allocated_size;
return this->allocator->GetAllocatedSize();
}
@ -761,10 +737,8 @@ void Squirrel::Uninitialize()
sq_pop(this->vm, 1);
sq_close(this->vm);
assert(this->allocator->allocated_size == 0);
/* Reset memory allocation errors. */
this->allocator->error_thrown = false;
this->allocator->Reset();
}
void Squirrel::Reset()