/*
This file is part of cpp-ethereum.
cpp-ethereum 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 3 of the License, or
(at your option) any later version.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2014
* Routines used by both the compiler and the expression compiler.
*/
#pragma once
#include <libsolidity/CompilerContext.h>
#include <libsolidity/ASTForward.h>
namespace dev {
namespace solidity {
class Type; // forward
class CompilerUtils
{
public:
CompilerUtils(CompilerContext& _context): m_context(_context) {}
/// Stores the initial value of the free-memory-pointer at its position;
void initialiseFreeMemoryPointer();
/// Copies the free memory pointer to the stack.
void fetchFreeMemoryPointer();
/// Stores the free memory pointer from the stack.
void storeFreeMemoryPointer();
/// Allocates a number of bytes in memory as given on the stack.
/// Stack pre: <size>
/// Stack post: <mem_start>
void allocateMemory();
/// Appends code that transforms memptr to (memptr - free_memptr) memptr
void toSizeAfterFreeMemoryPointer();
/// Loads data from memory to the stack.
/// @param _offset offset in memory (or calldata)
/// @param _type data type to load
/// @param _fromCalldata if true, load from calldata, not from memory
/// @param _padToWordBoundaries if true, assume the data is padded to word (32 byte) boundaries
/// @returns the number of bytes consumed in memory.
unsigned loadFromMemory(
unsigned _offset,
Type const& _type = IntegerType(256),
bool _fromCalldata = false,
bool _padToWordBoundaries = false
);
/// Dynamic version of @see loadFromMemory, expects the memory offset on the stack.
/// Stack pre: memory_offset
/// Stack post: value... (memory_offset+length)
void loadFromMemoryDynamic(
Type const& _type,
bool _fromCalldata = false,
bool _padToWordBoundaries = true,
bool _keepUpdatedMemoryOffset = true
);
/// Stores a 256 bit integer from stack in memory.
/// @param _offset offset in memory
/// @param _type type of the data on the stack
void storeInMemory(unsigned _offset);
/// Dynamic version of @see storeInMemory, expects the memory offset below the value on the stack
/// and also updates that. For reference types, only copies the data pointer. Fails for
/// non-memory-references.
/// @param _padToWordBoundaries if true, adds zeros to pad to multiple of 32 bytes. Array elements
/// are always padded (except for byte arrays), regardless of this parameter.
/// Stack pre: memory_offset value...
/// Stack post: (memory_offset+length)
void storeInMemoryDynamic(Type const& _type, bool _padToWordBoundaries = true);
/// Copies values (of types @a _givenTypes) given on the stack to a location in memory given
/// at the stack top, encoding them according to the ABI as the given types @a _targetTypes.
/// Removes the values from the stack and leaves the updated memory pointer.
/// Stack pre: <v1> <v2> ... <vn> <memptr>
/// Stack post: <memptr_updated>
/// Does not touch the memory-free pointer.
/// @param _padToWordBoundaries if false, all values are concatenated without padding.
/// @param _copyDynamicDataInPlace if true, dynamic types is stored (without length)
/// together with fixed-length data.
/// @note the locations of target reference types are ignored, because it will always be
/// memory.
void encodeToMemory(
TypePointers const& _givenTypes = {},
TypePointers const& _targetTypes = {},
bool _padToWordBoundaries = true,
bool _copyDynamicDataInPlace = false
);
/// Uses a CALL to the identity contract to perform a memory-to-memory copy.
/// Stack pre: <size> <target> <source>
/// Stack post:
void memoryCopy();
/// Appends code for an implicit or explicit type conversion. This includes erasing higher
/// order bits (@see appendHighBitCleanup) when widening integer but also copy to memory
/// if a reference type is converted from calldata or storage to memory.
/// If @a _cleanupNeeded, high order bits cleanup is also done if no type conversion would be
/// necessary.
void convertType(Type const& _typeOnStack, Type const& _targetType, bool _cleanupNeeded = false);
/// Creates a zero-value for the given type and puts it onto the stack. This might allocate
/// memory for memory references.
void pushZeroValue(Type const& _type);
/// Moves the value that is at the top of the stack to a stack variable.
void moveToStackVariable(VariableDeclaration const& _variable);
/// Copies an item that occupies @a _itemSize stack slots from a stack depth of @a _stackDepth
/// to the top of the stack.
void copyToStackTop(unsigned _stackDepth, unsigned _itemSize);
/// Moves a single stack element (with _stackDepth items on top of it) to the top of the stack.
void moveToStackTop(unsigned _stackDepth);
/// Moves a single stack element past @a _stackDepth other stack elements
void moveIntoStack(unsigned _stackDepth);
/// Removes the current value from the top of the stack.
void popStackElement(Type const& _type);
/// Removes element from the top of the stack _amount times.
void popStackSlots(size_t _amount);
template <class T>
static unsigned getSizeOnStack(std::vector<T> const& _variables);
static unsigned getSizeOnStack(std::vector<std::shared_ptr<Type const>> const& _variableTypes);
/// Appends code that computes tha SHA3 hash of the topmost stack element of 32 byte type.
void computeHashStatic();
/// Bytes we need to the start of call data.
/// - The size in bytes of the function (hash) identifier.
static const unsigned dataStartOffset;
/// Position of the free-memory-pointer in memory;
static const size_t freeMemoryPointer;
private:
/// Address of the precompiled identity contract.
static const unsigned identityContractAddress;
/// Stores the given string in memory.
/// Stack pre: mempos
/// Stack post:
void storeStringData(bytesConstRef _data);
/// Appends code that cleans higher-order bits for integer types.
void cleanHigherOrderBits(IntegerType const& _typeOnStack);
/// Prepares the given type for storing in memory by shifting it if necessary.
unsigned prepareMemoryStore(Type const& _type, bool _padToWordBoundaries) const;
/// Loads type from memory assuming memory offset is on stack top.
unsigned loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWordBoundaries);
CompilerContext& m_context;
};
template <class T>
unsigned CompilerUtils::getSizeOnStack(std::vector<T> const& _variables)
{
unsigned size = 0;
for (T const& variable: _variables)
size += variable->getType()->getSizeOnStack();
return size;
}
}
}
