/*
This file is part of solidity.
solidity 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.
solidity 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 solidity. 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/codegen/CompilerContext.h>
#include <libsolidity/ast/ASTForward.h>
namespace dev {
namespace solidity {
class Type; // forward
class CompilerUtils
{
public:
explicit 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.
/// Stack pre:
/// Stack post: <mem_start>
void fetchFreeMemoryPointer();
/// Stores the free memory pointer from the stack.
/// Stack pre: <mem_end>
/// Stack post:
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
/// Stack pre: <mem_end>
/// Stack post: <size> <mem_start>
void toSizeAfterFreeMemoryPointer();
/// Appends code that performs a revert, providing the given string data.
/// Will also append an error signature corresponding to Error(string).
/// @param _argumentType the type of the string argument, will be converted to memory string.
/// Stack pre: string data
/// Stack post:
void revertWithStringData(Type const& _argumentType);
/// 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 _padToWords if true, assume the data is padded to full words (32 bytes)
/// @returns the number of bytes consumed in memory.
unsigned loadFromMemory(
unsigned _offset,
Type const& _type = IntegerType(256),
bool _fromCalldata = false,
bool _padToWords = 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 _padToWords = 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 _padToWords 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 _padToWords = true);
/// Creates code that unpacks the arguments according to their types specified by a vector of TypePointers.
/// From memory if @a _fromMemory is true, otherwise from call data.
/// Calls revert if the supplied size is shorter than the static data requirements
/// or if dynamic data pointers reach outside of the area.
/// Also has a hard cap of 0x100000000 for any given length/offset field.
/// Stack pre: <source_offset> <length>
/// Stack post: <value0> <value1> ... <valuen>
void abiDecode(TypePointers const& _typeParameters, bool _fromMemory = false);
/// 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 _padToWords if false, all values are concatenated without padding.
/// @param _copyDynamicDataInPlace if true, dynamic types is stored (without length)
/// together with fixed-length data.
/// @param _encodeAsLibraryTypes if true, encodes for a library function, e.g. does not
/// convert storage pointer types to memory types.
/// @note the locations of target reference types are ignored, because it will always be
/// memory.
void encodeToMemory(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _padToWords,
bool _copyDynamicDataInPlace,
bool _encodeAsLibraryTypes = false
);
/// Special case of @a encodeToMemory which assumes tight packing, e.g. no zero padding
/// and dynamic data is encoded in-place.
/// Stack pre: <value0> <value1> ... <valueN-1> <head_start>
/// Stack post: <mem_ptr>
void packedEncode(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _encodeAsLibraryTypes = false
)
{
encodeToMemory(_givenTypes, _targetTypes, false, true, _encodeAsLibraryTypes);
}
/// Special case of @a encodeToMemory which assumes that everything is padded to words
/// and dynamic data is not copied in place (i.e. a proper ABI encoding).
/// Stack pre: <value0> <value1> ... <valueN-1> <head_start>
/// Stack post: <mem_ptr>
void abiEncode(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _encodeAsLibraryTypes = false
)
{
encodeToMemory(_givenTypes, _targetTypes, true, false, _encodeAsLibraryTypes);
}
/// Special case of @a encodeToMemory which assumes that everything is padded to words
/// and dynamic data is not copied in place (i.e. a proper ABI encoding).
/// Uses a new, less tested encoder implementation.
/// Stack pre: <value0> <value1> ... <valueN-1> <head_start>
/// Stack post: <mem_ptr>
void abiEncodeV2(
TypePointers const& _givenTypes,
TypePointers const& _targetTypes,
bool _encodeAsLibraryTypes = false
);
/// Decodes data from ABI encoding into internal encoding. If @a _fromMemory is set to true,
/// the data is taken from memory instead of from calldata.
/// Can allocate memory.
/// Stack pre: <source_offset> <length>
/// Stack post: <value0> <value1> ... <valuen>
void abiDecodeV2(TypePointers const& _parameterTypes, bool _fromMemory = false);
/// Zero-initialises (the data part of) an already allocated memory array.
/// Length has to be nonzero!
/// Stack pre: <length> <memptr>
/// Stack post: <updated_memptr>
void zeroInitialiseMemoryArray(ArrayType const& _type);
/// Copies full 32 byte words in memory (regions cannot overlap), i.e. may copy more than length.
/// Length can be zero, in this case, it copies nothing.
/// Stack pre: <size> <target> <source>
/// Stack post:
void memoryCopy32();
/// Copies data in memory (regions cannot overlap).
/// Length can be zero, in this case, it copies nothing.
/// Stack pre: <size> <target> <source>
/// Stack post:
void memoryCopy();
/// Converts the combined and left-aligned (right-aligned if @a _rightAligned is true)
/// external function type <address><function identifier> into two stack slots:
/// address (right aligned), function identifier (right aligned)
void splitExternalFunctionType(bool _rightAligned);
/// Performs the opposite operation of splitExternalFunctionType(_rightAligned)
void combineExternalFunctionType(bool _rightAligned);
/// Appends code that combines the construction-time (if available) and runtime function
/// entry label of the given function into a single stack slot.
/// Note: This might cause the compilation queue of the runtime context to be extended.
/// If @a _runtimeOnly, the entry label will include the runtime assembly tag.
void pushCombinedFunctionEntryLabel(Declaration const& _function, bool _runtimeOnly = true);
/// 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.
/// If @a _chopSignBits, the function resets the signed bits out of the width of the signed integer.
/// If @a _asPartOfArgumentDecoding is true, failed conversions are flagged via REVERT,
/// otherwise they are flagged with INVALID.
void convertType(
Type const& _typeOnStack,
Type const& _targetType,
bool _cleanupNeeded = false,
bool _chopSignBits = false,
bool _asPartOfArgumentDecoding = 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);
/// Pushes a pointer to the stack that points to a (potentially shared) location in memory
/// that always contains a zero. It is not allowed to write there.
void pushZeroPointer();
/// 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 an item that occupies @a _itemSize stack slots and has items occupying @a _stackDepth
/// slots above it to the top of the stack.
void moveToStackTop(unsigned _stackDepth, unsigned _itemSize = 1);
/// Moves @a _itemSize elements past @a _stackDepth other stack elements
void moveIntoStack(unsigned _stackDepth, unsigned _itemSize = 1);
/// Rotates the topmost @a _items items on the stack, such that the previously topmost element
/// is bottom-most.
void rotateStackUp(unsigned _items);
/// Rotates the topmost @a _items items on the stack, such that the previously bottom-most element
/// is now topmost.
void rotateStackDown(unsigned _items);
/// 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);
/// Pops slots from the stack such that its height is _toHeight.
/// Adds jump to _jumpTo.
/// Readjusts the stack offset to the original value.
void popAndJump(unsigned _toHeight, eth::AssemblyItem const& _jumpTo);
template <class T>
static unsigned sizeOnStack(std::vector<T> const& _variables);
static unsigned sizeOnStack(std::vector<std::shared_ptr<Type const>> const& _variableTypes);
/// Helper function to shift top value on the stack to the left.
/// Stack pre: <value> <shift_by_bits>
/// Stack post: <shifted_value>
void leftShiftNumberOnStack(unsigned _bits);
/// Helper function to shift top value on the stack to the right.
/// Stack pre: <value> <shift_by_bits>
/// Stack post: <shifted_value>
void rightShiftNumberOnStack(unsigned _bits);
/// Appends code that computes tha Keccak-256 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;
/// Position of the memory slot that is always zero.
static const size_t zeroPointer;
/// Starting offset for memory available to the user (aka the contract).
static const size_t generalPurposeMemoryStart;
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 _padToWords);
/// Loads type from memory assuming memory offset is on stack top.
unsigned loadFromMemoryHelper(Type const& _type, bool _fromCalldata, bool _padToWords);
CompilerContext& m_context;
};
template <class T>
unsigned CompilerUtils::sizeOnStack(std::vector<T> const& _variables)
{
unsigned size = 0;
for (T const& variable: _variables)
size += variable->annotation().type->sizeOnStack();
return size;
}
}
}
