You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 

130 lines
3.9 KiB

#pragma once
#include <vector>
#include "Common.h"
#include "Stack.h"
namespace dev
{
namespace eth
{
namespace jit
{
using instr_idx = uint64_t;
class BasicBlock
{
public:
class LocalStack
{
public:
/// Pushes value on stack
void push(llvm::Value* _value);
/// Pops and returns top value
llvm::Value* pop();
/// Duplicates _index'th value on stack
void dup(size_t _index);
/// Swaps _index'th value on stack with a value on stack top.
/// @param _index Index of value to be swaped. Must be > 0.
void swap(size_t _index);
size_t getMaxSize() const { return m_maxSize; }
int getDiff() const { return m_bblock.m_tosOffset; }
private:
LocalStack(BasicBlock& _owner);
LocalStack(LocalStack const&) = delete;
void operator=(LocalStack const&) = delete;
friend BasicBlock;
/// Gets _index'th value from top (counting from 0)
llvm::Value* get(size_t _index);
/// Sets _index'th value from top (counting from 0)
void set(size_t _index, llvm::Value* _value);
std::vector<llvm::Value*>::iterator getItemIterator(size_t _index);
private:
BasicBlock& m_bblock;
size_t m_maxSize = 0; ///< Max size reached by the stack.
};
explicit BasicBlock(instr_idx _firstInstrIdx, code_iterator _begin, code_iterator _end, llvm::Function* _mainFunc, llvm::IRBuilder<>& _builder, bool isJumpDest);
explicit BasicBlock(std::string _name, llvm::Function* _mainFunc, llvm::IRBuilder<>& _builder, bool isJumpDest);
BasicBlock(const BasicBlock&) = delete;
BasicBlock& operator=(const BasicBlock&) = delete;
llvm::BasicBlock* llvm() { return m_llvmBB; }
instr_idx firstInstrIdx() const { return m_firstInstrIdx; }
code_iterator begin() const { return m_begin; }
code_iterator end() const { return m_end; }
bool isJumpDest() const { return m_isJumpDest; }
llvm::Value* getJumpTarget() const { return m_jumpTarget; }
void setJumpTarget(llvm::Value* _jumpTarget) { m_jumpTarget = _jumpTarget; }
LocalStack& localStack() { return m_stack; }
/// Optimization: propagates values between local stacks in basic blocks
/// to avoid excessive pushing/popping on the EVM stack.
static void linkLocalStacks(std::vector<BasicBlock*> _basicBlocks, llvm::IRBuilder<>& _builder);
/// Synchronize current local stack with the EVM stack.
void synchronizeLocalStack(Stack& _evmStack);
/// Prints local stack and block instructions to stderr.
/// Useful for calling in a debugger session.
void dump();
void dump(std::ostream& os, bool _dotOutput = false);
private:
instr_idx const m_firstInstrIdx = 0; ///< Code index of first instruction in the block
code_iterator const m_begin = {}; ///< Iterator pointing code beginning of the block
code_iterator const m_end = {}; ///< Iterator pointing code end of the block
llvm::BasicBlock* const m_llvmBB;
/// Basic black state vector (stack) - current/end values and their positions on stack
/// @internal Must be AFTER m_llvmBB
LocalStack m_stack;
llvm::IRBuilder<>& m_builder;
/// This stack contains LLVM values that correspond to items found at
/// the EVM stack when the current basic block starts executing.
/// Location 0 corresponds to the top of the EVM stack, location 1 is
/// the item below the top and so on. The stack grows as the code
/// accesses more items on the EVM stack but once a value is put on
/// the stack, it will never be replaced.
std::vector<llvm::Value*> m_initialStack;
/// This stack tracks the contents of the EVM stack as the basic block
/// executes. It may grow on both sides, as the code pushes items on
/// top of the stack or changes existing items.
std::vector<llvm::Value*> m_currentStack;
/// How many items higher is the current stack than the initial one.
/// May be negative.
int m_tosOffset = 0;
/// Is the basic block a valid jump destination.
/// JUMPDEST is the first instruction of the basic block.
bool const m_isJumpDest = false;
/// If block finishes with dynamic jump target index is stored here
llvm::Value* m_jumpTarget = nullptr;
};
}
}
}